An analytical model to evalulate the static soil pressure on a buried structure

A discrete-continuous model to analyze a buried structure response to static surface loading as well as the soil gravitational load at ‘service-state’ conditions is presented. A two-degree-of-freedom model represents the structure above which a continuous vertical column represents the soil. The proposed model simulates the soil-buried structure interaction affected by the structure’s roof displacement as well as the rigid body displacement of the whole structure relative to that of the free field. The model can represent positive and negative arching and provides an understanding of the effects that various variables have on the arching type and on the structure response. Other soil-structure parameters that are included in the model are the soil and structure material properties, roof span and thickness, the structure’s height, and the depth of burial and external pressure. Simulations of a rectangular buried conduit performed by both the proposed model and by a finite element analysis yielded similar interface loads and similar influence of the problem parameters on the results. This example demonstrates the effect of the structure’s stiffness and height on the soil arching above it and on the average interface load acting on its roof. Thus, the proposed model can be used in preliminary stages of the design process to easily evaluate the effect of variables such as the structure properties on the response.