Study on mechanical analysis model and settlement law of overburden layer of shallow buried highway tunnel arch during operation period
When the shallow buried shield tunnel passes through the existing highway,the soil overburden layer at different depths of the tunnel vault will be settled under the action of vehicle load.For this problem,a two-stage settlement analysis model for the overburden layer of the vault in the process of shield tunneling was proposed,and the ABAQUS numerical simulation(FEM)was used to verify the correctness of the settlement model.The results show that the equivalent two-stage settlement model,which is modified by the soil volume loss parameter in Peck's formula and based on the Boussinesq solution under nonlinear loading,is effective in predicting the development of the settlement of the overburden layer at the end of the shield vault under the coupling of cyclic loading of the vehicle and the tunnel shield.During the shield construction process,the increasing settlement disturbance zone of the overburden layer at the top of the shield tail arch is located from the approach zone to the first 2/5 of the underpass zone.Then the settlement disturbance is slowed down after the settlement peak in the underpass zone,and the settlement disturbance decreases in the away zone.The settlement development law is in accordance with the Protodyakonov pressure arch theory,and the settlement increase mainly occurs during the pressure arch damage.After the completion of the shield,the vehicle cyclic load affects the settlement of the overburden layer at a depth of about 5 m,and the vehicle load at a depth of 5 m or more occurs as stress diffusion.The main influencing factor of settlement is the volume loss of soil caused by tunnel excavation.
万方数据
维普
