Effect of plane strain on pore pressure parameters

A theoretical as well as a laboratory investigation into the effects of plane strain on pore pressure parameters is presented. Other observations relative to stress-strain relationships, intermediate principal stress values and shear strength parameters (c´ø´) in terms of effective stresses are also reported. Experimental work consisted of the following three types of Undrained Triaxial tests with pore pressure measurements: (1) Standard triaxial tests on cylindrical specimens. (2) Triaxial tests on rectangular specimens. (3) Confined tests on rectangular specimens, in which lateral expansion was prevented in one direction, to achieve plane strain condition. A strain-controlled triaxial machine equipped with a non-flow null indicating type pore pressure measuring device was used for all shear tests. The observed data show that for the soil tested the values of pore pressure ,parameter A[subscript]f and shear strength parameter (c´ø´) under plane strain condition are higher than those obtained in corresponding triaxial tests. Failure is observed to occur, in the case of plane strain tests, at strains much smaller than those for the corresponding triaxial tests.Applied Science, Faculty ofCivil Engineering, Department ofGraduat