Reinforced embankments for the causeway for a North Wales bridge project PROJECT: PONT BRIWET TR13-518 V3 PROJECT: PONT BRIWET DATE: 22/07/2013 TR13-518 V3 DATE: 22/07/2013 RESULTS - ANALYSIS WITH RESSA RESULTSCH240 - ANALYSISEmbankment WITH RESSA- access road SECTION SECTION CH240 Embankment - access road Loading Nominal value Factor (kPa) Nominal Factor 368 value 1.35 (kPa) 368 1.35 368 258 1.35 368 1.35 258 258 1.35 NA NA 258 1.35 NA NA 5.20 m OD 1.10 m OD 5.20 m OD 4.10m 1.10 m OD 4.25 4.10m 1.00 m 4.25 m OD 1V:2H 1.00 m 3 layers Tenax HM3 @ 300mm ; L = 20m (tbc) 61V:2H layers Tenax TT045 @ 500mm ; L = 10 m (tbc) 3 layers Tenax- CH240) HM3 @ (tbc 300mm ; L = 20m (tbc) 50 m (CH190 for quantities) 6 layers Tenax TT045 @ 500mm ; L = 10 m (tbc) 50 m (CH190 - CH240) (tbc for quantities) Temporary access road - causeway Loading Rig (1) Rig (2) Rig (1) (1) LR1100 Rig (2) (2) LR1100 LR1100 (1) LTM 1750 LR1100 (2) LTMlevel: 1750 Top Toe level: Top level: Height: Toe level: Water level: Height: surcharge Distance: Water level:face: from slope Distance: surcharge Slope: from slope face: Reinforcement: Slope: Reinforcement: Assumed length: 4a Assumed length: SECTION CH380 (CH380 - CH440) SECTION CH380 (CH380 - CH440) Loading Loading Rig (1) Rig (2) Rig (1) (1) LR1100 Rig (2) (2) LR1100 LR1100 (1) LTM 1750 LR1100 (2) LTMlevel: 1750 Top Toe level: Top level: Height: Toe level: Water level: Height: surcharge Distance: Water level:face: from slope Distance: surcharge Slope: from slope face: Reinforcement: Slope: Reinforcement: Assumed length: Assumed length: Distance to edge of emb D = 1.00m to edge of Track Length Distance FS FSemb D = 1.00m (m) Slope 1:1.5 Slope 1:2 Track Length FS FS 2.95 0.96 1.03 (m) Slope 1:1.5 Slope 1:2 0.80 1.11 2.95 0.96 1.03 4.30 1.06 0.80 1.11 0.90 1.28 4.30 1.06 NA 0.90 1.28 NA Temporary access road - causeway Distance to edge of emb D = 1.00m to edge of Track Length Distance FS FSemb D = 1.00m (m) Slope 1:1.5 Slope 1:2 Track Length FS FS 2.95 0.97 1.02 (m) Slope 1:1.5 Slope 1:2 0.80 1.12 2.95 0.97 1.02 4.30 1.07 0.80 1.12 0.90 1.31 4.30 1.07 NA 0.90 1.31 NA Nominal value Factor (kPa) Nominal Factor 368 value 1.15 (kPa) 368 1.15 368 258 1.15 368 258 1.15 258 1.15 NA NA 258 1.15 NA NA 3.20 m OD 1.062 m OD 3.20 m OD 2.14 1.062mmOD OD 2.36 2.14 m 1.00 m 2.36 m OD 1V:2H 1.00 m 3 layers Tenax HM3 @ 300mm ; L = 20m (tbc) 1V:2H 3 layers Tenax TT045 @ 500mm ; L = 10 m (tbc) 3 layers Tenax- CH440) HM3 @ (tbc 300mm ; L = 20m (tbc) 60 m (CH380 for quantities) 3 layers Tenax TT045 @ 500mm ; L = 10 m (tbc) 60 m (CH380 - CH440) (tbc for quantities) 4b FIGURE 4a and 4b Results: Stability analysis Section CH240 (4a) and CH380 (4b) 14 fines, and the embankment fill was designed with a locally modified Class 6N material (classifications according to the Specifications for Highways Works, Series 600). * Reinforced fill properties: ¶ Class 6B: Selected coarse granular material used for starter layer, with no fines (Particle sizes: 11.8 inches (300 mm) to 4.9 inches (125 mm) ¶ Class 6N: Selected well-graded granular material to use for embankment fill ¶ Friction angle Φ'=40˚ ¶ Unit weight γ=129 pounds per cubic foot (20 kN/m3) ¶ Cohesion C'=0 psf (0 kPa) Ground conditions in the estuary comprised deep loose sands over dense gravels incorporating cobbles overlying rock. * Foundation soil properties: ¶ MD Sand ¶ Friction angle Φ'=33˚ ¶ Unit weight γ=122 pounds per cubic foot (19 kN/m3) Reinforced embankments Design standards The reinforced embankments were designed based on the limit equilibrium analysis in accordance with BS80061:2010 for the internal stability and Eurocode 7 (BS EN 1997-1:2004) for the global stability. We used the method from Rowe and Soderman (1985) to estimate the stability of a reinforcement embankment for bearing capacity and the methods of reinforcement proposed by Giroud, Holtz and Bonaparte (1985), modified here in conjunction with the properties of the geogrids (Figure 5). For the working platforms, we used the BRE470 guidance with a modified method based on bearing capacity and loading distribution to incorporate the biaxial geogrids for reinforcement. Geosynthetics | October November 2020 1020GS_p10-17.indd 14 9/22/20 12:21 AM