Mechanical analysis method and anti-fracture design of shallow buried subway tunnels under normal fault dislocation
Earthquake damage investigation exhibits that damage to tunnels crossing active fault zones is extremely severe.Here,taking the interval tunnel crossing Jiaocheng fault zone of Taiyuan urban rail transit line 1 phase 1 project as engineering support,a mechanical analysis model was established with Pasternak dual-parameter foundation model,and the analytical solution to longitudinal response of underground pipeline under normal fault dislocation was derived.Then,a 3D refined finite element(FE)model was established using the software ABAQUS.The analytical solution calculation results agreed well with FE numerical simulation results to verify the correctness of the analytical solution.Finally,a combination of segment lining-flexible joints was adopted within the designated key fortification area,effects of segment length,longitudinal position of joints and width of flexible joints on the overall disaster mitigation effect of tunnel structure were analyzed contrastively.The results showed that the analytical solution calculation of longitudinal response of underground pipeline under normal fault dislocation can provide a reference for determination of key fortification area;combination of segmental lining and flexible joints can effectively reduce degree and range of damage to tunnel structure;during normal fault dislocation action,the shorter the segment length,the smaller the range of damage to tunnel structure;increase in width of flexible joint can reduce degree and range of damage to tunnel structure,and damage area can be concentrated at ends of segment lining structure;when using butt joint mode to set flexible joints,the deformation energy-absorption effect of joint can be maximized,and its disaster mitigation effect is the optimal;the study results can provide theoretical basis for anti-fracture design and analysis of tunnel engineering projects crossing active fault zone using a combination of segments and flexible joints.
万方数据
维普
