Research On Ground Settlement Controls Of Shallow And Large Section Loess Tunnel Through High Speed Highway

In engineering geology, loess occupies a special status because of the special ingredients and nature. Engineering characteristics show considerable differences between the loess tunnels and ordinary rock tunnel. Loess tunnels in Zhengzhou-Xi'an passenger dedicated railway line are representative because of the V-Q3 new loess, shallow-buried, large-section and more under-pass characteristics. It shows how to solve the questions about ground settlement controls, excavation and support methods.This paper discussed the mechanism of the effective application that control ground settlement of the shallow and large section Loess tunnel through highway on the basis of the Chinese and foreign literature in a wide range of research, analyzed the coordinating role among the tunnel, pipe roof, grouting and other auxiliary supporting structures based on the interaction between the rock and supporting structures. This paper applied K.H.Park analytic method to forecast the ground settlement, and applied the FLAC and ANSYS software to numerical simulation in different excavation method, different excavation footage, different grouting shelf parameters, different advancing supporting forms and different initial supporting modulus of elasticity conditions. The software simulated the ground settlement, the vault settlement and the rock deformation to analyze and optimize the parameters of advancing supporting and reasonable safety excavation method. Crossing Wenxiang tunnel in Zhengzhou-Xi'an passenger dedicated railway line as an example, the paper compared the anticipated results, the numerical results and the measured field data to verify the correctness and feasibility, and obtained the surface subsidence control standards of loess tunnels, and provided the analysis, design and construction experience.