To reasonably capture the magnitude

distribution

resultant force

and action point height of lateral earth pressure with depth on retaining structures for a circular foundation pit in unsaturated soils

the inclination angle of the soil sliding surface behind retaining structures was first derived. The derivation

suitable for both uniform and linear profiles of suction stress

was based on the suction stress theory of unsaturated soils and the limit equilibrium method. Subsequently

a method for calculating lateral earth pressure on retaining structures of circular foundation pits in unsaturated soils was introduced by integrating the characteristics of vertical and circumferential soil arches to account for the spatial soil arching effect. Additionally

the proposed calculation method was validated by comparing it with existing theoretical solutions and model test data

and the influence of relevant factors was analyzed. The results show that the proposed calculation method not only demonstrates excellent consistency with existing theoretical solutions and model test data

confirming its accuracy and rationality

but also effectively addresses the comprehensive effects of unsaturated formation

spatial soil arching

and structure-soil contact parameters on the lateral earth pressure of circular foundation pits. This contributes to optimizing the design and construction of circular foundation pits. Consequently

the proposed calculation method holds theoretical significance and promising practical applications. The resultant force of lateral earth pressure for a foundation pit significantly decreases with an increase in absolute value of surface suction stress

circumferential stress coefficient

and external cohesion. However

the variation in the action point height of the resultant force remains relatively minor. Lateral earth pressure under a linear profile of suction stress is greater than under a uniform profile. However

the variation in lateral earth pressure is more pronounced under the uniform profile of suction stress