Lateral extrusion analysis of sandwiched weak soil in slurry trench

This paper presents a method to analyze the problem of lateral extrusion of sandwiched weak soil in a slurry trench. This problem is modeled as weak material compressed between rough plates. Theoretical solutions are derived on the basis of the limiting plasticity theory. The arching effect due to the finite length of the trench is taken into account in the computation of vertical pressure being exerted upon the weak soil. The derived theoretical solutions are reduced to simple forms that can be used in practice. The stability of sandwiched weak soil is evaluated using a factor of stability that represents a measurement of the effectiveness of slurry pressure on preventing weak soil from lateral extrusion. This factor is defined as a ratio of slurry pressure to lateral extrusion pressure at the level of weak soil. Validity of the proposed method is examined using a field case study.