An examination of some theories of earth pressure on shaft linings

Abstract

Various theories for determining the earth pressure on shaft linings in cohesionless soils are discussed, and results are presented for a Coulomb-type analysis with a conical sliding surface. The assumed shape of the failure surface approximates closely the one given in published results obtained by the method of characteristics. The simplicity of the cone permits an investigation of a number of parameters, e.g. the earth pressure coefficient on radial planes, which turns out to be a decisive parameter in the analysis, and accounts for the widely differing published values for earth pressures on shaft linings. Certain theories could lead, especially at greater depths, to rather conservative designs.A similar theory is also presented for earth pressures on shafts in cohesive soils. In this case the possibility of base failure must be considered as well, and it is shown that this might be the deciding failure mechanism.