3D Finite Elements Analysis of Pipe-Soil Interaction-Effects of Groundwater

摘要

This work is an extension of the study on 3D Finite Element Analysis of Pipe/Soil Interaction, and is aimed at analyzing the effects of groundwater on the soil-pipe interaction forces, for various loading conditions, and assuming either drained or undrained conditions. Back analyses of large scale tests of lateral loading of a rigid pipe in dry and saturated sand are used to infer the changes in the shear strength of sands induced by soil saturation. Besides changes in frictional strength induced by reduction of effective confining stresses, it is found that soil saturation also affects the apparent cohesion. Those findings are used for simulating several situations analysed in the original study, and obtaining the force-displacement relations for saturated conditions. A theoretical study is performed to infer the effects of soil saturation on pipe-soil interaction forces for pipes buried in clay. A relation accounting for changes in the failure mechanism with undrained shear strength is introduced for the case of lateral loading, and a method for estimating the interaction forces for pipes buried in saturated clays and subjected to complex loading is proposed.