Analytical Prediction Method of Ground Settlement Deformation of Tunnel Under Structure

Abstract:

The analytical prediction method for ground settlement deformation of underground tunnels considering the surface building (structure) load-induced ground settlement due to tunnel excavation takes the structural load as an equivalent distributed load. It establishes analytical models for the deformation field of surrounding rock under the action of half-space structural load and the buried tunnel under the condition of no load in the half-space. Based on the calculation results of the two models, the ground settlement deformation under the condition of structure-underpass tunnels is predicted. For the deformation field of the surrounding rock under the action of the half-space structural load, the integral of the uniformly distributed force applied to the surface is used to obtain the stress distribution formula of the half-space, and then the displacement field distribution caused by the building load in the half-space is calculated. For the buried tunnel under the condition of no load in the half-space, the Airy stress function is used to obtain the displacement field expression of the tunnel excavation in the semi-infinite space based on the simplified form of the shallow-buried tunnel problem. On the basis of the two solutions, the analytical solution for the ground settlement deformation caused by the underpass tunnel under the influence of surface building loads is obtained. Through this analytical prediction, the ground settlement characteristics under the combined action of structural load and tunnel excavation are analyzed, and the settlement curve is drawn to analyze the surface settlement pattern. The calculated settlement deformation and the measured settlement data are compared, and the result shows that the relative error between the calculated value and the measured value is 3.9%, which proves that the calculation model can well describe the coupling effect of building load and tunnel excavation, and verifies the accuracy and applicability of the calculation model.