盐渍土地层隧道底部衬砌厚度缺陷对衬砌安全性影响分析

盐渍土地层隧道在运营期间底部结构产生的病害层出不穷，隧底的病害缺陷直接影响衬砌结构承载力。在全面调查新疆某隧道底部病害的基础上，运用ANSYS软件建立“荷载-结构”模型，改变隧底不同位置的衬砌厚度值，模拟衬砌厚度缺陷，分析典型截面安全系数的演变规律。结果表明:墙脚作为应力集中的部位，是隧道衬砌受力的最不利部位；隧底厚度缺陷值，围岩条件直接影响隧道衬砌结构的安全性能。拱顶安全系数随隧底厚度缺陷的增加而增大；左墙脚、右墙脚同时发生厚度缺陷时，拱顶安全系数上升最明显。

Analysis on the Influence of the Thickness Defect of the Lining at the Bottom of the Saline Soil Layer Tunnel on the Safety of Lining

Endless diseases are produced at the bottom structure of the saline soil layer tunnel during operation, which directly affects the bearing capacity of lining structure. Based on the overall investigation of the bottom diseases of Xinjiang Yanshuigou Tunnel and by virtue of ANSYS software, load-structure model is established, the lining thickness values of different positions at the bottom of the tunnel are changed, the lining thickness defects are simulated and the evolvement rules of the safety factor of typical sections is analyzed. The results show that the foot of wall, as the stress concentration part, is the unfavorable part for lining force; the thickness defect of the tunnel bottom and conditions of the surrounding rock affect the safty of the lining of the tunnel; the safety factor of the crown is increased with the increase of the defect of the tunnel bottom; when the left and right wall foot have the thickness defect simultaneously, the safety factor of the crown is increased most significantly.