The embedment depth equations of a rigid retaining wall,which can meet different anti-overturning stability coefficients,was derived by using the unified solution of shear strength in the plane strain condition for the unsaturated soils.The effects of the unsaturated characteristics and the intermediate principal stress on the shear strength were also taken into consideration.Direct use of these equations can plot the influences of the intermediate principal stress,the matric suction,and the stability coefficient on the embedment depth of a rigid retaining wall. The closed-form solutions are an orderly set of new results and these solutions provide more choices and optimizations for the design of foundation pits with different types and features.The results showed that both the intermediate principal stress and the matric suction have obvious influences on the embedment depth of a retaining wall,i.e.,the embedment depth decreases remarkably with the increase of the intermediate principal stress or matric suction.In addition,different failure criteria have an obvious effect on the anti-overturning design of a retaining wall;the greater stability coefficient designed,the greater is the embedment depth,which is also related to the excavation depth of a foundation pit.Finally,the results provide a theoretical basis for the analysis and evaluation about the work performance and the safety reserve of the retaining wall of a foundation pit in the unsaturated soils.
