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Numerical analysis of stone column supported foundations
203A 875249 Clay contamination of road layers on glacial till subgrades Cochrane. S R Proc International Conference on Construction in Glacial Tills and Boulder Clays, Edinburgh, 12-14 March 1985 P87-91. Puhl Edinburgh Engineering Technics Press. 1985 Stone penetration into clay subgrades and consequent upward flow of clay. or a pumping action caused by dynamic loading, result in clay contamination and weakening of granular stone sub-bases. Static and dynamic laboratory tests have modelled this phenomenon. Glacial tills with large clay fractions and moisture content above optimum produce conditions where contamination is likely. Geotextiles with appropriate opening size reduce clay contamination and stone penetration. Sand filled geotextile composites were particularly suitable and provided an effective drainage filter.
Foundations See also: 875111, 875154 875250
Flexibility coefficient and interaction factors for pile group analysis E1 Sharnouby. B: Novak, M Can Geoteeh J V23. N4. ,Voc 1986, P441-450
875253
Foundation engineering: grounds for inno,,ation Buttfield, A Cit, Engng, London ..tpril 1987. P17-24 Improvements in continuous flight auger piling to prevent pile necking, a new method of trimming to length for cast in situ concrete piles, a nev,' method of construction of stone columns for site improvement, the shear tube anchor, and in situ deep stabilisation of v,'atcrlogged silty sands with cement or grout are described. 875254
Numerical analysis of stone column supported foundations Schweiger, H F: Pande, G N Comput Geotech 1"2, N6. 1986. P347-3"2 Failure loads are evaluated for rafts resting on stone column reinforced clays. It is assumed that the influence of the columns is uniform and homogeneous and that no slip occurs at the soil-column interface. An eqt, ivalent material model is formulated, combining the critical state model t'or clay and the Mohr-Coulomb criterion for gravels. Results of finite element analysis of flexible and rigid circular footings are presented. The influence on the dilatancy of the columns and the difference in behaviour of columns at the centre and the edge of the raft are evident. 875255
Many analyses using interaction factors to describe the behaviour of pile groups are not sufficiently accurate for practical use. An analysis is presented which removes some of the limitations of previous work and provides flexibility coefficients and interaction factors which facilitate the analysis of pile groups. Rigid or flexible caps, a wide range of pile-soil parameters and soil profiles, and pile separation from the soil can be accommodated. The analysis is, in this case, limited to static horizontal loading of pile groups and assumes a linear soil and small displacements.
A method for the design of footings subjected to horizontal or inclined loads is presented. It is derived from experimental results. Two bearing capacity diagrams illustrate the relationship established between the method and known shear failure analysis methods.
875251
875256
Behaviour of rigid piles in layered soils under eccentric and inclined loads
Experience with the application of jet-grouting for underpinning in southern Germany (In German)
Sastry, V V R N: Meyerhof. G G; Koumoto, T Can Geotech J V23. N4. Nor 1986. P451-457
Schubert, A Geotechnik V9, :V4, 1986, P181-196
An instrumented, rigid model pile, jacked through clay into sand, was subjected to vertical eccentric and central inclined loads. Lateral soil pressures on the shaft, base load, and pile cap displacement were measured. Earlier analyses for pile behaviour in homogeneous soils are extended to describe piles in a layered system. Calculated bearing capacity and displacements are in reasonable agreement with observed behaviour.
Case histories of underpinning using jet grouting are presented, with a general description of the technique, some specific advantages, and testing procedures. Some cases of failure are illustrated, and their causes and remedial measures discussed.
Bearing capacity of footings on sand, subjected to horizontal loads (In German) Foik, G Geoteehnik V9. N3. 1986. P125-I36
875257
Plastic collapse of long piles under inclined loading. Technical note on practical applications
875252
Foundations of the Annacis cable-stayed bridge Bazett, D J: McCammon, N R Can Geotech J V23, N4. Not 1986. P458-471
Murff, J D lnt J Num Anal ~leth Geomech VI 1, ,V2. March-.4pril 1987, P185-192
Support for this bridge in British Columbia, Canada. is provided by piles driven into dense overconsolidated Quaternary sediments. On the south bank they are close to the surface, but on the north bank they are overlain by 80-85m of weak aliuvial and deltaic materials. The site investigation, design considerations taking into account impact loads, earthquakeinduced liquefaction, and permitted settlement, test pile program, and final design are presented. The north main pier was founded on unusually deep piles about 85m long.
Offshore pile foundations are often required to resist axial and lateral loads, and a means for estimating the stren~_th of a pile tinder combined loading is required. The method presented is based on the upper bound method of plasticity. The incorporation of plastic yield interaction between axial load and moment for the pile is a key feature of the method. The solution can be represented as a graph representing axial and lateral load interaction and can be incorporated into analysis of pile groups.
(~ 1987 Pergamon Journals Ltd. Reproduction not permitted
Foundations See also: 875111, 875154 875250
Flexibility coefficient and interaction factors for pile group analysis E1 Sharnouby. B: Novak, M Can Geoteeh J V23. N4. ,Voc 1986, P441-450
875253
Foundation engineering: grounds for inno,,ation Buttfield, A Cit, Engng, London ..tpril 1987. P17-24 Improvements in continuous flight auger piling to prevent pile necking, a new method of trimming to length for cast in situ concrete piles, a nev,' method of construction of stone columns for site improvement, the shear tube anchor, and in situ deep stabilisation of v,'atcrlogged silty sands with cement or grout are described. 875254
Numerical analysis of stone column supported foundations Schweiger, H F: Pande, G N Comput Geotech 1"2, N6. 1986. P347-3"2 Failure loads are evaluated for rafts resting on stone column reinforced clays. It is assumed that the influence of the columns is uniform and homogeneous and that no slip occurs at the soil-column interface. An eqt, ivalent material model is formulated, combining the critical state model t'or clay and the Mohr-Coulomb criterion for gravels. Results of finite element analysis of flexible and rigid circular footings are presented. The influence on the dilatancy of the columns and the difference in behaviour of columns at the centre and the edge of the raft are evident. 875255
Many analyses using interaction factors to describe the behaviour of pile groups are not sufficiently accurate for practical use. An analysis is presented which removes some of the limitations of previous work and provides flexibility coefficients and interaction factors which facilitate the analysis of pile groups. Rigid or flexible caps, a wide range of pile-soil parameters and soil profiles, and pile separation from the soil can be accommodated. The analysis is, in this case, limited to static horizontal loading of pile groups and assumes a linear soil and small displacements.
A method for the design of footings subjected to horizontal or inclined loads is presented. It is derived from experimental results. Two bearing capacity diagrams illustrate the relationship established between the method and known shear failure analysis methods.
875251
875256
Behaviour of rigid piles in layered soils under eccentric and inclined loads
Experience with the application of jet-grouting for underpinning in southern Germany (In German)
Sastry, V V R N: Meyerhof. G G; Koumoto, T Can Geotech J V23. N4. Nor 1986. P451-457
Schubert, A Geotechnik V9, :V4, 1986, P181-196
An instrumented, rigid model pile, jacked through clay into sand, was subjected to vertical eccentric and central inclined loads. Lateral soil pressures on the shaft, base load, and pile cap displacement were measured. Earlier analyses for pile behaviour in homogeneous soils are extended to describe piles in a layered system. Calculated bearing capacity and displacements are in reasonable agreement with observed behaviour.
Case histories of underpinning using jet grouting are presented, with a general description of the technique, some specific advantages, and testing procedures. Some cases of failure are illustrated, and their causes and remedial measures discussed.
Bearing capacity of footings on sand, subjected to horizontal loads (In German) Foik, G Geoteehnik V9. N3. 1986. P125-I36
875257
Plastic collapse of long piles under inclined loading. Technical note on practical applications
875252
Foundations of the Annacis cable-stayed bridge Bazett, D J: McCammon, N R Can Geotech J V23, N4. Not 1986. P458-471
Murff, J D lnt J Num Anal ~leth Geomech VI 1, ,V2. March-.4pril 1987, P185-192
Support for this bridge in British Columbia, Canada. is provided by piles driven into dense overconsolidated Quaternary sediments. On the south bank they are close to the surface, but on the north bank they are overlain by 80-85m of weak aliuvial and deltaic materials. The site investigation, design considerations taking into account impact loads, earthquakeinduced liquefaction, and permitted settlement, test pile program, and final design are presented. The north main pier was founded on unusually deep piles about 85m long.
Offshore pile foundations are often required to resist axial and lateral loads, and a means for estimating the stren~_th of a pile tinder combined loading is required. The method presented is based on the upper bound method of plasticity. The incorporation of plastic yield interaction between axial load and moment for the pile is a key feature of the method. The solution can be represented as a graph representing axial and lateral load interaction and can be incorporated into analysis of pile groups.
(~ 1987 Pergamon Journals Ltd. Reproduction not permitted