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Rock anchoring on a steep slope
344A
SURFACE STRUCTURES:EARTH RETAINERS
Slopes 957300
Reliabifity appfied to slope stabifity analysis J. T. Christian, C. C. Ladd & G. B. Baecher, Journal o f Geoteehnical Engineering- ASCE, 120(12), 1994, pp 21802207. This paper describes how probabilistic descriptions of soil parameters can be derived from field and laboratory data and applied in stability analysis. The first-order, second-moment approach is explored and applied to the design of embankment dams. The example illustrates the relative contributions of uncertainties about different parameters to the reliability of the embankment. Reliability analysis is especially useful in establishing design values of factors of safety representing consistent risks for different types of failure. (from Authors) 957301
The design and analysis of a marine trial embankment on a landslip in glacial till A. K. C. Smith, Proceedings - ICE: Geoteehnieal Engineering, 113(1), 1995, pp 3-18. The new A55 North Waies Coast Road runs along the foreshore at Llanddulas, east of Colwyn Bay, crossing an area about 1 km long with a history of deep-seated landslips. The landslips occur in glacial deposits overlying limestone. The road runs on a rock-fall embankment which is designed to stabilize the slips by providing a toe loading. It was calculated that, in the long term, the embankment would increase the safety factors of the existing slips by a minimum of 20%. However, short-term safety factors were low. It was therefore decided to test the short-term stability by building a trial embankment, and measuring movements and pore pressures induced by construction. Pore pressures induced by construction of the trial were generally similar to those calculated using simple soil mechanics theory and the results of standard laboratory tests. However, dissipation was slower than indicated by in-situ permeability tests, and safety factors were consequently lower than expected. During the early stages of construction, movements of about 0.5 mm per day were detected near the interface between two clay strata. However, by controlling the rates of construction, it was found possible to complete the trial successfully. The results were used to specify rates of construction for the main works. (from Author)
tensile loads are compared with two proposed methods that consider both force equilibrium and displacement compatibility. An example multiple-layered cover system is used to compare predictions from the four methods. The comparison indicates that displacement compatibility is an important consideration and can influence predictions significantly for tensile load. (from Authors)
957304
Stabifity of compacted clay slopes using a nonlinear faile~e envelope R. W. Day & M. Maksimovic, Bulletin - Association o f Engineering Geologists, 31(4), 1994, pp 516-520. Limiting equilibrium models, which divide the failure mass into vertical slices, are commonly used to determine the factor of safety of a slope. An example of a limiting equilibrium model is the Bishop Simplified Method. In order to determine the factor of safety of the slope, the slope geometry, soil properties (density and shear strength), and groundwater conditions must be known. The shear strength of the soil is commonly represented by a linear shear strength envelope. The objective of this study was to calculate the factor of safety using the conventional linear shear strength envelope and compare that to the factor of safety from the nonlinear effective shear strength envelope for a compacted clay. (from Authors)
957305
Green banks of the futmm G. Shirley, Surveyor, 182(5337), 1995, pp 20-21. Geosynthetics are now widely used in the construction of soft faced reinforced soil embankments. However, many materials are unable to sustain vegetative growth on the face of the reinforced soil mass. A system to overcome this is described. Developed by Phi Group for the retention of steeply sloping banks, soil panel is an assembly of steel lattice modules to provide structural strength to the face, geotextile meshes for stability, and Green fix mats for the containment of soils. This allows for the construction of 'green' retaining walls. The system is soon to be used in Leicestershire. The advantages of using such a system are described. (S.E.Brown)
957302
Rock anchoring on a steep slope ANON, International Construction, 34(2), 1995, p 62. Rock anchoring was one of the techniques used by drilling contractors in mesh stabilisation of a steep road embankment in the UK. The upper slope was formed of soft soils overlying shales with steep slip planes. The lower slopes were hard rock. Hand drilling and duckbill anchors were used on the upper slopes. Percussion drilling and reinforced bars and grouting were used on the lower slopes. Permanent stabilisation works will involve the construction of a retaining wall. (J.M.McLaughlin) 957303
Geosynthetic loads in landfills slopes: displacement compntibifity J. H. Long, R. B. Gilbert & J. J. Daly, Journal o f Geotechnical Engineering - ASCE, 120(11), 1994, pp 20092025. Lining- and cover-system components must be designed to resist tensile loads anticipated. Four methods for determining tensile loads are examined. Two common design methods, called the limit equilibrium method (LEM) and the limit method (LM), that consider only force equilibrium to predict
Earth retaining structures
957306 Collapse of geogrid-reinforced retaining strncture G. A. Leonards, 3. D. Frost & J. D. Bray, Journal o f Performance o f Constructed Facilities - ASCE, 8(4), 1994, pp 274-292. The use of cohesive soils in geogdd-reinforced backfills requires consideration of the performance of these materials under as-compacted and long-term conditions. Depending on the as-compacted conditions, the long-term performance, as a result of in service saturation, can lead to strength loss and failure of such structures. This paper documents the case history of a gcogdd reinforced retaining wail, constructed with cohesive backfill, that failed. The results of extensive field and laboratory testing programs and engineering analyses to investigate the causes of failure are presented. Deficiencies in design and construction quality control are identified. (from Authors)
SURFACE STRUCTURES:EARTH RETAINERS
Slopes 957300
Reliabifity appfied to slope stabifity analysis J. T. Christian, C. C. Ladd & G. B. Baecher, Journal o f Geoteehnical Engineering- ASCE, 120(12), 1994, pp 21802207. This paper describes how probabilistic descriptions of soil parameters can be derived from field and laboratory data and applied in stability analysis. The first-order, second-moment approach is explored and applied to the design of embankment dams. The example illustrates the relative contributions of uncertainties about different parameters to the reliability of the embankment. Reliability analysis is especially useful in establishing design values of factors of safety representing consistent risks for different types of failure. (from Authors) 957301
The design and analysis of a marine trial embankment on a landslip in glacial till A. K. C. Smith, Proceedings - ICE: Geoteehnieal Engineering, 113(1), 1995, pp 3-18. The new A55 North Waies Coast Road runs along the foreshore at Llanddulas, east of Colwyn Bay, crossing an area about 1 km long with a history of deep-seated landslips. The landslips occur in glacial deposits overlying limestone. The road runs on a rock-fall embankment which is designed to stabilize the slips by providing a toe loading. It was calculated that, in the long term, the embankment would increase the safety factors of the existing slips by a minimum of 20%. However, short-term safety factors were low. It was therefore decided to test the short-term stability by building a trial embankment, and measuring movements and pore pressures induced by construction. Pore pressures induced by construction of the trial were generally similar to those calculated using simple soil mechanics theory and the results of standard laboratory tests. However, dissipation was slower than indicated by in-situ permeability tests, and safety factors were consequently lower than expected. During the early stages of construction, movements of about 0.5 mm per day were detected near the interface between two clay strata. However, by controlling the rates of construction, it was found possible to complete the trial successfully. The results were used to specify rates of construction for the main works. (from Author)
tensile loads are compared with two proposed methods that consider both force equilibrium and displacement compatibility. An example multiple-layered cover system is used to compare predictions from the four methods. The comparison indicates that displacement compatibility is an important consideration and can influence predictions significantly for tensile load. (from Authors)
957304
Stabifity of compacted clay slopes using a nonlinear faile~e envelope R. W. Day & M. Maksimovic, Bulletin - Association o f Engineering Geologists, 31(4), 1994, pp 516-520. Limiting equilibrium models, which divide the failure mass into vertical slices, are commonly used to determine the factor of safety of a slope. An example of a limiting equilibrium model is the Bishop Simplified Method. In order to determine the factor of safety of the slope, the slope geometry, soil properties (density and shear strength), and groundwater conditions must be known. The shear strength of the soil is commonly represented by a linear shear strength envelope. The objective of this study was to calculate the factor of safety using the conventional linear shear strength envelope and compare that to the factor of safety from the nonlinear effective shear strength envelope for a compacted clay. (from Authors)
957305
Green banks of the futmm G. Shirley, Surveyor, 182(5337), 1995, pp 20-21. Geosynthetics are now widely used in the construction of soft faced reinforced soil embankments. However, many materials are unable to sustain vegetative growth on the face of the reinforced soil mass. A system to overcome this is described. Developed by Phi Group for the retention of steeply sloping banks, soil panel is an assembly of steel lattice modules to provide structural strength to the face, geotextile meshes for stability, and Green fix mats for the containment of soils. This allows for the construction of 'green' retaining walls. The system is soon to be used in Leicestershire. The advantages of using such a system are described. (S.E.Brown)
957302
Rock anchoring on a steep slope ANON, International Construction, 34(2), 1995, p 62. Rock anchoring was one of the techniques used by drilling contractors in mesh stabilisation of a steep road embankment in the UK. The upper slope was formed of soft soils overlying shales with steep slip planes. The lower slopes were hard rock. Hand drilling and duckbill anchors were used on the upper slopes. Percussion drilling and reinforced bars and grouting were used on the lower slopes. Permanent stabilisation works will involve the construction of a retaining wall. (J.M.McLaughlin) 957303
Geosynthetic loads in landfills slopes: displacement compntibifity J. H. Long, R. B. Gilbert & J. J. Daly, Journal o f Geotechnical Engineering - ASCE, 120(11), 1994, pp 20092025. Lining- and cover-system components must be designed to resist tensile loads anticipated. Four methods for determining tensile loads are examined. Two common design methods, called the limit equilibrium method (LEM) and the limit method (LM), that consider only force equilibrium to predict
Earth retaining structures
957306 Collapse of geogrid-reinforced retaining strncture G. A. Leonards, 3. D. Frost & J. D. Bray, Journal o f Performance o f Constructed Facilities - ASCE, 8(4), 1994, pp 274-292. The use of cohesive soils in geogdd-reinforced backfills requires consideration of the performance of these materials under as-compacted and long-term conditions. Depending on the as-compacted conditions, the long-term performance, as a result of in service saturation, can lead to strength loss and failure of such structures. This paper documents the case history of a gcogdd reinforced retaining wail, constructed with cohesive backfill, that failed. The results of extensive field and laboratory testing programs and engineering analyses to investigate the causes of failure are presented. Deficiencies in design and construction quality control are identified. (from Authors)