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Horizontal soil stress changes around displacement piles. Short communication
295A well suited to small computers. Factors affecting the accuracy of the solution are discussed. Finite strip solutions are shown to be in good agreement with analytical solutions.
9O533O Negative skin friction on pile groups Chow, Y K; Chin, J T; Lee, S L int J Num Anal Meth Geomech VI4, N2, March 1990, P7591
905326 Evaluation of allowable pressure under foundations. Technical note Reznik, Y M Geotech Test J V13, NI, March 1990, P53-57
Downdrag analysis for group piles which penetrate a consolidating upper layer to socket in a firm bearing stratum is presented. Settlement of the upper layer under surcharge is estimated using Terzaghi's one dimensional consolidation theory. Parametric studies indicate the influence of various geometric and material properties on downdrag and associated pile head settlement. In general, downdrag forces on pile groups are smaller than for single piles, provided full slippage at the interface does not occur. Reasonable agreement is found between theory and field observations.
Plate bearing tests were carried out on water saturated loessial soils in open pits and boreholes in order to investigate the effect of surcharge on plate bearing results. Surcharge around the bearing plate of area 600 sq cm was simulated using a specially designed device. Results indicate the limit of proportionality without surcharge was at least 25°/. lower than when surcharge is applied.
905327 Theoretical study of pile heave Chow, Y K; Teh, C I Geotecimique V40, N1, March 1990, PI-14 Ground displacement when a pile is driven causes heave of piles already installed. A study of vertical soil movement and pile heave during pile driving in a clay deposit idealised as a homogeneous, isotropic, incompressible, linear elastic half space is presented. Numerical results illustrate how soil movements are affected by the dimensions of the penetrating pile. Pile heave is influenced by ratio of Young's modulus of the pile and soil, pile dimensions and pile spacings. Results are in good agreement with field observations.
905328 Bearing capacity of reinforced horizontal sandy ground Huang, C C; Tatsuoka, F Gcorext Geomem V9, NI, 1990, P51-82 Plane strain model tests were carried out using a footing of sand with horizontal reinforcement. Effects of length, arrangement, strength, and rigidity of the reinforcement were evaluated, and strain field in the sand, tensile forces in the reinforcement, and footing contact pressure distribution measured. Bearing capacity was markedly increased by reinforcement of similar length to the footing, but increased length had little extra effect. Bearing capacity was controlled by failure in the reinforced zone immediately beneath the footing or failure of the sand beneath the reinforced zone, whichever was weaker. A method of stability analysis based on the limit equilibrium method is presented.
905329 Downdrng and axial load on piles Kog, Y C Ground Engng V23, N3, April 1990, P24-30 Detailed examination of a failure of piles due to combined axial load and negative skin friction at a recent fill site with 817m layers of soft clay over dense clayey sand (Kalang Formation, Singapore) is presented. Interaction of downdrag and axial load and the combined effect of pile force distribution along the shaft are discussed. Not all piles in the group need to be designed for negative skin friction, even where large settlements are expected. A governing criterion relating axial force and downdrag is developed to indicate where downdrag must be taken into account.
905331 Horizontal soil stress changes around displacement piles. Short communication Sayed, S M; Clemente, J L M lnt d Num Anal Meth Geomech V14, N2, March 1990, P131138 A simplified analysis of horizonal soil stress changes caused by placement of a pile is presented. Assumptions include only horizontal soil displacement occurs and a weightless nonlinear elastic soil. The derived expression is used to predict stress changes around single and group piles and to estimate ultimate load and efficiency of pile groups. Comparison is made between output of the simplified analysis and results of full scale load tests in sand.
905332 Shaft resistance of piles in clay Azzouz, A S; Baligh, M M; Whittle, A J J Geotech Engng Div ASCE VII6, N2, Feb 1990, P205-221 A new method for evaluation of axial capacity of friction piles in moderately overconsolidated (OCR less than 4) clay is presented. The analysis assumes single, vertical, rigid piles in deep deposits exhibiting normalised behaviour, undrained penetration, excess pore pressure dissipation, and undrained loading conditions. Limiting skin friction is expressed as a product of lateral earth pressure coefficient at the end of consolidation and a skin friction ratio (skin friction/effective horizontal stress after pore pressure dissipation). Kc is affected by both OCR and sensitivity of the deposit.
905333 Finite element simulation of belutviour of laterally loaded pries in pernmfrost Foriero, A; Ladanyi, B J Geotech Engng Div ASCE V116, N2, Feb 1990, P266-284 The computer code RDPIL.FOR for laterally loaded piles in a viscoelastic soil is described. It uses a Maxwell model to accommodate the time-independent initial elastic modulus, k. Input requirements are Poisson's ratio, creep parameters (from pressuremeter or triaxial tests), and k (preferably from pile tests). Predictions of the program are compared to displacements, deflections, bending moments, and soil reactions from lateral loading tests in permafrost.
© 1990 Pergamon Press plc. Reproduction not permitted
9O533O Negative skin friction on pile groups Chow, Y K; Chin, J T; Lee, S L int J Num Anal Meth Geomech VI4, N2, March 1990, P7591
905326 Evaluation of allowable pressure under foundations. Technical note Reznik, Y M Geotech Test J V13, NI, March 1990, P53-57
Downdrag analysis for group piles which penetrate a consolidating upper layer to socket in a firm bearing stratum is presented. Settlement of the upper layer under surcharge is estimated using Terzaghi's one dimensional consolidation theory. Parametric studies indicate the influence of various geometric and material properties on downdrag and associated pile head settlement. In general, downdrag forces on pile groups are smaller than for single piles, provided full slippage at the interface does not occur. Reasonable agreement is found between theory and field observations.
Plate bearing tests were carried out on water saturated loessial soils in open pits and boreholes in order to investigate the effect of surcharge on plate bearing results. Surcharge around the bearing plate of area 600 sq cm was simulated using a specially designed device. Results indicate the limit of proportionality without surcharge was at least 25°/. lower than when surcharge is applied.
905327 Theoretical study of pile heave Chow, Y K; Teh, C I Geotecimique V40, N1, March 1990, PI-14 Ground displacement when a pile is driven causes heave of piles already installed. A study of vertical soil movement and pile heave during pile driving in a clay deposit idealised as a homogeneous, isotropic, incompressible, linear elastic half space is presented. Numerical results illustrate how soil movements are affected by the dimensions of the penetrating pile. Pile heave is influenced by ratio of Young's modulus of the pile and soil, pile dimensions and pile spacings. Results are in good agreement with field observations.
905328 Bearing capacity of reinforced horizontal sandy ground Huang, C C; Tatsuoka, F Gcorext Geomem V9, NI, 1990, P51-82 Plane strain model tests were carried out using a footing of sand with horizontal reinforcement. Effects of length, arrangement, strength, and rigidity of the reinforcement were evaluated, and strain field in the sand, tensile forces in the reinforcement, and footing contact pressure distribution measured. Bearing capacity was markedly increased by reinforcement of similar length to the footing, but increased length had little extra effect. Bearing capacity was controlled by failure in the reinforced zone immediately beneath the footing or failure of the sand beneath the reinforced zone, whichever was weaker. A method of stability analysis based on the limit equilibrium method is presented.
905329 Downdrng and axial load on piles Kog, Y C Ground Engng V23, N3, April 1990, P24-30 Detailed examination of a failure of piles due to combined axial load and negative skin friction at a recent fill site with 817m layers of soft clay over dense clayey sand (Kalang Formation, Singapore) is presented. Interaction of downdrag and axial load and the combined effect of pile force distribution along the shaft are discussed. Not all piles in the group need to be designed for negative skin friction, even where large settlements are expected. A governing criterion relating axial force and downdrag is developed to indicate where downdrag must be taken into account.
905331 Horizontal soil stress changes around displacement piles. Short communication Sayed, S M; Clemente, J L M lnt d Num Anal Meth Geomech V14, N2, March 1990, P131138 A simplified analysis of horizonal soil stress changes caused by placement of a pile is presented. Assumptions include only horizontal soil displacement occurs and a weightless nonlinear elastic soil. The derived expression is used to predict stress changes around single and group piles and to estimate ultimate load and efficiency of pile groups. Comparison is made between output of the simplified analysis and results of full scale load tests in sand.
905332 Shaft resistance of piles in clay Azzouz, A S; Baligh, M M; Whittle, A J J Geotech Engng Div ASCE VII6, N2, Feb 1990, P205-221 A new method for evaluation of axial capacity of friction piles in moderately overconsolidated (OCR less than 4) clay is presented. The analysis assumes single, vertical, rigid piles in deep deposits exhibiting normalised behaviour, undrained penetration, excess pore pressure dissipation, and undrained loading conditions. Limiting skin friction is expressed as a product of lateral earth pressure coefficient at the end of consolidation and a skin friction ratio (skin friction/effective horizontal stress after pore pressure dissipation). Kc is affected by both OCR and sensitivity of the deposit.
905333 Finite element simulation of belutviour of laterally loaded pries in pernmfrost Foriero, A; Ladanyi, B J Geotech Engng Div ASCE V116, N2, Feb 1990, P266-284 The computer code RDPIL.FOR for laterally loaded piles in a viscoelastic soil is described. It uses a Maxwell model to accommodate the time-independent initial elastic modulus, k. Input requirements are Poisson's ratio, creep parameters (from pressuremeter or triaxial tests), and k (preferably from pile tests). Predictions of the program are compared to displacements, deflections, bending moments, and soil reactions from lateral loading tests in permafrost.
© 1990 Pergamon Press plc. Reproduction not permitted