View allAll Photos Tagged Backfill
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
Backfilling in Jersey City, NJ with control density fill (CDF) as an added safety measure. Spectra Energy’s NJ-NY Expansion Project is being built to meet growing natural gas demand in the nation’s largest metropolitan area. 12/2012
Day143
Still backfilling uploads... but I have been keeping up with my photo-a-day, even throughout my long time abroad :) so watch this space...
FGR: live free or die!
Showcasing my new hair cut.
Texture by playingwithbrushes
Very much in the style of boy wonder
Fidalgo Bay.
Phase III, 2019: Final phase of remedial action for approximately 10.4 acres of subtidal sediments; 4.7 acres of those sediments support eelgrass. The planned Phase III remedial action, as proposed, consists of:
Placement of a thin layer cap (between 2 to 8-inch thickness) over approximately 10 acres of subtidal sediments with dioxin concentration greater than 10 nanograms per kilogram (ppt) TEC (but less than 25 ppt) Dredging and backfilling 0.46 acres of sediment in excess of 25 ppt dioxins and wood waste accumulation greater than 1-foot below the mud line within eelgrass beds.
Eelgrass mitigation using advanced mitigation plantings from Phase II along with additional mitigation efforts to compensate for the loss of eelgrass bed due to dredging (0.38 acres out of 0.46 acre dredge footprint supports eelgrass)
Phase II, 2013: the Department of Ecology removed old creosote dock pilings and other in-water concrete and metal structures. Dug up and dredged about 10 acres of sediment contaminated with dioxins and wood waste. Disposed of contaminated sediment off-site.Improve the near-shore habitat by reshaping an existing spit and jetty. Connected Fidalgo Bay with the wetland area that was created in 2011. The site was vacant property (2013) with abandoned building remnants and debris. A sawmill and wood-box factory, and then a plywood mill, operated on the site for almost a century. Mill features included a hog-fuel boiler, drum storage tank area, transformer yard, above-ground storage tanks containing fuel oil, gasoline, diesel and/or propane, phenolic formaldehyde resin and caustic storage tanks (both used in making plywood glue), a machine shop, a metal shop, and an area for spraying paint and oil.
Phase I, 2011: work focused on cleaning up about 6 upland acres. It included removing pilings and other structures to allow excavation of about 33,600 tons of contaminated soil; off-site disposal of the soil, structures and pilings; and backfilling the site with about 39,000 tons of clean soil. Site soil contains elevated concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, zinc, oil-range petroleum hydrocarbons, dioxins, and furans. Groundwater beneath the site does not meet drinking water standards. The water also contains elevated concentrations of arsenic, copper and nickel. Dioxins and wood debris contaminate Marine sediments are found to be contaminated with dioxins and wood debris.
Please feel free to use this photo but be sure to credit ArmchairBuilder.com and provide this link...
armchairbuilder.com/resources/how-to-build-your-own-home
Thanks,
Michael
ArmchairBuilder.com
As designed, spring snowmelt carried by the Columbia River backfills into the historic floodplain at Steigerwald Lake National Wildlife Refuge in southwest Washington, June 20, 2022. USFWS video: Toshio Suzuki
After years of restoration work, Steigerwald Lake National Wildlife Refuge reopened in May of 2022 and is doing exactly what it was designed to do: Allow spring snowmelt from the Columbia River to fill the historic flood plain.
The massive, 960-acre project included levee deconstruction, fish relocations, the raising of a highway, and the planting of more than 500,000 trees and shrubs at the refuge east of Vancouver, Washington.
The two-year project, referred to as the largest habitat restoration project ever on the lower Columbia River, is already creating new space for wildlife.
- How to visit: www.fws.gov/refuge/steigerwald-lake
Hitachi Zaxis ZX160 with engcon EC-Oil Automatic Quick Hitch System, EC219 Tiltrotator, Compactor Plate and a Rammer breaker. Contractor: Sundsvalls Grävteknik. Operator: Patrik Garefelt. Photo: Sten Strömgren
As designed, spring snowmelt carried by the Columbia River backfills into the historic floodplain at Steigerwald Lake National Wildlife Refuge in southwest Washington, June 20, 2022. USFWS video: Toshio Suzuki
After years of restoration work, Steigerwald Lake National Wildlife Refuge reopened in May of 2022 and is doing exactly what it was designed to do: Allow spring snowmelt from the Columbia River to fill the historic flood plain.
The massive, 960-acre project included levee deconstruction, fish relocations, the raising of a highway, and the planting of more than 500,000 trees and shrubs at the refuge east of Vancouver, Washington.
The two-year project, referred to as the largest habitat restoration project ever on the lower Columbia River, is already creating new space for wildlife.
- How to visit: www.fws.gov/refuge/steigerwald-lake
Hitachi Zaxis ZX160 with engcon EC-Oil Automatic Quick Hitch System, EC219 Tiltrotator, Compactor Plate and a Rammer breaker. Contractor: Sundsvalls Grävteknik. Operator: Patrik Garefelt. Photo: Sten Strömgren
Fidalgo Bay.
Phase III, 2019: Final phase of remedial action for approximately 10.4 acres of subtidal sediments; 4.7 acres of those sediments support eelgrass. The planned Phase III remedial action, as proposed, consists of:
Placement of a thin layer cap (between 2 to 8-inch thickness) over approximately 10 acres of subtidal sediments with dioxin concentration greater than 10 nanograms per kilogram (ppt) TEC (but less than 25 ppt) Dredging and backfilling 0.46 acres of sediment in excess of 25 ppt dioxins and wood waste accumulation greater than 1-foot below the mud line within eelgrass beds.
Eelgrass mitigation using advanced mitigation plantings from Phase II along with additional mitigation efforts to compensate for the loss of eelgrass bed due to dredging (0.38 acres out of 0.46 acre dredge footprint supports eelgrass)
Phase II, 2013: the Department of Ecology removed old creosote dock pilings and other in-water concrete and metal structures. Dug up and dredged about 10 acres of sediment contaminated with dioxins and wood waste. Disposed of contaminated sediment off-site.Improve the near-shore habitat by reshaping an existing spit and jetty. Connected Fidalgo Bay with the wetland area that was created in 2011. The site was vacant property (2013) with abandoned building remnants and debris. A sawmill and wood-box factory, and then a plywood mill, operated on the site for almost a century. Mill features included a hog-fuel boiler, drum storage tank area, transformer yard, above-ground storage tanks containing fuel oil, gasoline, diesel and/or propane, phenolic formaldehyde resin and caustic storage tanks (both used in making plywood glue), a machine shop, a metal shop, and an area for spraying paint and oil.
Phase I, 2011: work focused on cleaning up about 6 upland acres. It included removing pilings and other structures to allow excavation of about 33,600 tons of contaminated soil; off-site disposal of the soil, structures and pilings; and backfilling the site with about 39,000 tons of clean soil. Site soil contains elevated concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, zinc, oil-range petroleum hydrocarbons, dioxins, and furans. Groundwater beneath the site does not meet drinking water standards. The water also contains elevated concentrations of arsenic, copper and nickel. Dioxins and wood debris contaminate Marine sediments are found to be contaminated with dioxins and wood debris.
Backfilling the sheet piling wall - approximately 2,000 cubic yard fo sand was trucked in for this part of the project.
Hitachi Zaxis ZX160 with engcon EC-Oil Automatic Quick Hitch System, EC219 Tiltrotator, Compactor Plate and a Rammer breaker. Contractor: Sundsvalls Grävteknik. Operator: Patrik Garefelt. Photo: Sten Strömgren
Fidalgo Bay.
Phase III, 2019: Final phase of remedial action for approximately 10.4 acres of subtidal sediments; 4.7 acres of those sediments support eelgrass. The planned Phase III remedial action, as proposed, consists of:
Placement of a thin layer cap (between 2 to 8-inch thickness) over approximately 10 acres of subtidal sediments with dioxin concentration greater than 10 nanograms per kilogram (ppt) TEC (but less than 25 ppt) Dredging and backfilling 0.46 acres of sediment in excess of 25 ppt dioxins and wood waste accumulation greater than 1-foot below the mud line within eelgrass beds.
Eelgrass mitigation using advanced mitigation plantings from Phase II along with additional mitigation efforts to compensate for the loss of eelgrass bed due to dredging (0.38 acres out of 0.46 acre dredge footprint supports eelgrass)
Phase II, 2013: the Department of Ecology removed old creosote dock pilings and other in-water concrete and metal structures. Dug up and dredged about 10 acres of sediment contaminated with dioxins and wood waste. Disposed of contaminated sediment off-site.Improve the near-shore habitat by reshaping an existing spit and jetty. Connected Fidalgo Bay with the wetland area that was created in 2011. The site was vacant property (2013) with abandoned building remnants and debris. A sawmill and wood-box factory, and then a plywood mill, operated on the site for almost a century. Mill features included a hog-fuel boiler, drum storage tank area, transformer yard, above-ground storage tanks containing fuel oil, gasoline, diesel and/or propane, phenolic formaldehyde resin and caustic storage tanks (both used in making plywood glue), a machine shop, a metal shop, and an area for spraying paint and oil.
Phase I, 2011: work focused on cleaning up about 6 upland acres. It included removing pilings and other structures to allow excavation of about 33,600 tons of contaminated soil; off-site disposal of the soil, structures and pilings; and backfilling the site with about 39,000 tons of clean soil. Site soil contains elevated concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, zinc, oil-range petroleum hydrocarbons, dioxins, and furans. Groundwater beneath the site does not meet drinking water standards. The water also contains elevated concentrations of arsenic, copper and nickel. Dioxins and wood debris contaminate Marine sediments are found to be contaminated with dioxins and wood debris.
Filey Holiday camp was the biggest of Billy Butlin's camps. It extended to some 400 acres and eventually accommodating nearly 11,000 campers.When the station opened most holiday makers traveled to the camp by train but as the years went by more and more people came by car until it was uneconomic to keep the station open. The last train ran on Saturday 17th July 1977.
All platforms, concourse, exit steps, fencing and concrete lampposts are still in situ - the lampposts even still have the public address speakers attached. The site now derelict, with the once vital passenger subway backfilled and flooded.
Springline Construction Services crew backfilling installed casing pipes under Seymour Parkway westbound off-ramp, July 14 2021.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
Fidalgo Bay.
Phase III, 2019: Final phase of remedial action for approximately 10.4 acres of subtidal sediments; 4.7 acres of those sediments support eelgrass. The planned Phase III remedial action, as proposed, consists of:
Placement of a thin layer cap (between 2 to 8-inch thickness) over approximately 10 acres of subtidal sediments with dioxin concentration greater than 10 nanograms per kilogram (ppt) TEC (but less than 25 ppt) Dredging and backfilling 0.46 acres of sediment in excess of 25 ppt dioxins and wood waste accumulation greater than 1-foot below the mud line within eelgrass beds.
Eelgrass mitigation using advanced mitigation plantings from Phase II along with additional mitigation efforts to compensate for the loss of eelgrass bed due to dredging (0.38 acres out of 0.46 acre dredge footprint supports eelgrass)
Phase II, 2013: the Department of Ecology removed old creosote dock pilings and other in-water concrete and metal structures. Dug up and dredged about 10 acres of sediment contaminated with dioxins and wood waste. Disposed of contaminated sediment off-site.Improve the near-shore habitat by reshaping an existing spit and jetty. Connected Fidalgo Bay with the wetland area that was created in 2011. The site was vacant property (2013) with abandoned building remnants and debris. A sawmill and wood-box factory, and then a plywood mill, operated on the site for almost a century. Mill features included a hog-fuel boiler, drum storage tank area, transformer yard, above-ground storage tanks containing fuel oil, gasoline, diesel and/or propane, phenolic formaldehyde resin and caustic storage tanks (both used in making plywood glue), a machine shop, a metal shop, and an area for spraying paint and oil.
Phase I, 2011: work focused on cleaning up about 6 upland acres. It included removing pilings and other structures to allow excavation of about 33,600 tons of contaminated soil; off-site disposal of the soil, structures and pilings; and backfilling the site with about 39,000 tons of clean soil. Site soil contains elevated concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, zinc, oil-range petroleum hydrocarbons, dioxins, and furans. Groundwater beneath the site does not meet drinking water standards. The water also contains elevated concentrations of arsenic, copper and nickel. Dioxins and wood debris contaminate Marine sediments are found to be contaminated with dioxins and wood debris.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
Grindstone found in 11th/12th century backfill of pit in medieval enclosure.
To find out more visit: www.wessexarch.co.uk/projects/kent/margate
River Dargle Flood Defence Scheme.
These images were taken towards the end of the second week of February 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
And, at the same time, the guys are clearing away material used to build access ramps down into the riverbed.
The thought crossed my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
Was on a quest to do an Alice In Wonderland photo... defeated, I went home and started on the garden.... then my daughter agreed to snap a few.
Red snoot from below camera right. green backfill against against intruding leaves. Beauty light camera left - Jeez, I can't remember... 1/2, 1/2/ 1/2 respectively.... hopefully EXIF data is there for you.
Backfilled and forgotten, the Butterhouse tunnel was dug in the early 1880's, opening for freight traffic in 1885. It closed for good in 1966. 329 yards in length, the tunnel incorporates a gentle curve to the south towards its western end. It boasts a patchwork of red and engineering brick, with refuges provided for platelayers and ceramic tablets in the north sidewall to benefit the local ganger's note-taking. A high-level row of cable hangers is also apparent, together with hundreds of short stalactites. Today, a low mist hung in the the tunnel on our arrival, but only to a height of about two metres or so. Climbing above it, we were rewarded with a wonderful green river of mist which made for some super photo opportunities.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
Crews use a large steel container to bring material into the headhouse used to temporarily backfill the approach to the cross-cut cavern, so heavy machinery can more easily move in and out during drilling operations.
The backfilling of the MacArthur Ditch is part of the larger Kissimmee River Restoration project. The U.S. Army Corps of Engineers project will eliminate an artificial drainage feature in the floodplain that was created more than 50 years ago by the MacArthur family to protect their property from flooding.
A small borrow canal resulting from the construction of a levee around this property has grown to almost 3 miles in length and up to 60 feet wide as a result of the reintroduction of flow to the Phase I restoration area in 2001. This dated feature drains the floodplain quickly while it continues to grow in length and width. If not backfilled, it would decrease the inundation depth and duration of water in the floodplain wetlands and impact the quality of fish and wildlife habitat.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.
If this tram tunnel's construction dates back to the 1750s, which is when the limekilns this tunnel serves were built, then it could well be the oldest railway tunnel in Scotland at ~260 years old. Even if it's not quite that old then I'd imagine it's still a very old structure and it's in brilliant condition considering that it's basically been buried. Both portals have been backfilled, although enough of a gap exists at the southern portal to squeeze inside.
I'd say the tunnel is around 25 to 35 yards in length, lined with stone and it's dry throughout. There is also a distinct gradient with the tunnel climbing to the north. If you track the tramway up to the quarries, you'll see that it has a long way to climb before it reaches the former quarries.
When I first came to this tunnel at the beginning of 2013, we more or less found it by accident. The only clue to it's existence was a tunnel shown on the tourist board at the bottom of the limekilns. Thankfully, the relatively secretive nature of the tunnel means that it's not been vandalised.
The tunnel has seen a lot of backfill since it's closure but if you walk down the middle, you can just about stand up properly. This photo was taken from the completely backfilled northern portal and looks down towards the light you can see intruding from the mostly backfilled southern portal.
Scaffolding has been erected inside the partially-backfilled cross-cut cavern to aid workers drilling pilot holes for future soil grouting pipes ahead of station cavern excavation.
Looking south at construction of the MacArthur Ditch backfill project. The initial work of a spoil plug has been placed on the south end of the ditch and the backfill continues northward.
River Dargle Flood Defence Scheme.
These images were taken towards the end of the second week of February 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
And, at the same time, the guys are clearing away material used to build access ramps down into the riverbed.
The thought crossed my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
River Dargle Flood Defence Scheme.
These images were taken towards the end of the second week of February 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
And, at the same time, the guys are clearing away material used to build access ramps down into the riverbed.
The thought crossed my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
River Dargle Flood Defence Scheme.
These images were taken during the second week of March 2017.
These are the critical stabilisation works at the Silverbridge site, adjacent to the N11 dual-carriageway:
Back in November 2014, we'd observed bank stabilisation works here involving excavation, repair and building of a support wall structure -- carried out by JONS Construction on behalf of the National Roads Authority.
We would occasionally catch sight of this work in the distance. Quite an impressive little piece of structural engineering.
Having built a retaining concave wall, backfilled for solidity, they were also drilling, fixing and sealing ground anchors to pin the entire structure together.
Now we see that further works are being undertaken.
Word has it that extra ‘stabilisation work’ had to be done to protect the integrity of the riverbank.
At the section here we can see that there’s not much space between the edge of the rock face and the Armco at the side of the dual-carriageway.
Have yet to determine what precisely that will entail. Serious work to reinforce the side access ramp down to the river.
The N11 carriageway runs adjacent to this sunken side of the riverbank -- barely 2 (large) paces divide the two. Even with twin strips of Armco along the roadside, it's perilously close. Traffic speeds along this stretch (maximum speed 100 kmp). Only needs a touch from a heavy vehicle to cause secondary impact, which (worst possible scenario) could result in something going airborne.
Working in these confined spaces puts a premium of safety and communication.
The guys have hard-filled a working shelf on the riverbed, to allow machinery access to the rockface. Obviously some serious drilling is called for before a form of extra 'pinning' is put in place.
They have sunk a series of hollowed tubes/casings -- obviously to form the foundations of a more extensive structure.
And some investigative work around the transverse buttress of the access bridge, parallel to the heavy-duty pipeline carrying water down from the Vartry reservoir.
At a (rough) guess -- I'd say the foundations were sunk to a depth of approx 4+m.
With such secure foundations in place, they would then look to construct a substantial bank of material, and/or retaining wall (similar to that in place further along the roadside bank).
=================================================
Previously the guys drilled and sunk 4+metre deep reinforced tubing and rods along a newly laid concrete base. Those stubs were then used to attach steel rod cradles -- which, in turn, were filled with poured concrete. Result - the wall quickly rises. Variation on the method they've used elsewhere along this stretch of the river.
A continuous stretch of protective wall has now been poured, and joined up with the section originally erected back in 2014.
As we can see from the side-on shot, the base of the wall has pre-cut openings for the retaining pins that have been driven into the side wall of the roadside cliff. These have been sealed and capped.
Progress has been rapid, the full stretch of wall is completed, and the guys are now working on back-filling the empty space between the protective wall and the roadside rock face. You don't just throw in a few trucks loads of soil and hope for the best. You load, layer, level and compress.
By now the guys had clearing away material used to build access ramps down into the riverbed.
The thought crossed had my mind -- in doing so (removing the stone-filled gabions etc,) are they potentially exposing the river bank on that side to erosion, slippage etc?
We know the destructive force of fast running waters. Hell, this is precisely why the protective works have been carried out along the rest of the stretch, down to the Bray Harbour. Unless they have other plans to stabilise it, what is going to be left here is loose soil -- very close to the access road into the halting site itself.
Now that we can see the cleaned, exposed riverbank, we can see a substantial bedrock. Clearly this is not liable to subsidence. And there evidence that sections of the slope had already been 'nailed' * to prevent slippage. But, in talking to the guys there, it would seem that further 'nailing' might be required later in the year.
Some repair/reinforcing work is going on here to protect the (old) buttress that supports the pipework carrying water to the Bray region.
*
Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes.
The technique involves the insertion of relatively slender reinforcing elements into the slope – often general purpose reinforcing bars (rebar) although proprietary solid or hollow-system bars are also available.
Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses.