公路隧道进口滑坡分析与治理方案比选

Analysis and Comparison of Treatment Plans About Landslide of Highway Tunnel Entrance

以桐梓至新浦高速公路舒家岩隧道进口滑坡为工程背景,先进行滑坡成因分析,再进行稳定性分析和治理方案比选。为了获得较准确的计算参数,参考《公路滑坡防治设计规范》,先根据监测数据和钻探判断第一滑面上部坡体处于蠕滑阶段,稳定系数Fs取0.98;而第二滑面无明显滑动迹象,稳定系数Fs取1.05;结合土工试验,采用极限平衡法反算滑坡力学参数值,并通过传递系数法计算第一滑面处坡体的剩余下滑力(1449.10 kN/m),边坡急需采取抗滑措施。为了提高滑坡治理后隧道进洞施工的安全性,根据滑坡发展情况,对抗滑桩支挡与回填反压方案进行了方案比选,结果表明,抗滑桩方案工程费用较小,有利于运行期间山体的稳定性,对环境影响较小;回填反压方案工程费用大,易诱发次生滑坡的发生,故选择抗滑桩方案,并取得良好的治理效果。

Taking the landslide at the entrance of the Shujiayan Tunnel of Tongzi-Xinpu expressway as the engineering background,the cause of the landslide was analyzed first,and then the landslide stability evaluation and treatment scheme screening were carried out.In order to obtain more accurate calculation parameters,refer to the Design Specification for Highway Landslide Prevention and Control,based on monitoring data and drilling verification,it was determined that the upper slope of the first sliding surface was in the creep stage,and the stability coefficient Fs was taken as 0.98.The second sliding surface shown no obvious signs of sliding,and the stability coefficient Fs=1.05.Through soil test and back analysis,the mechanical parameters of the landslide were analyzed,and the surplus glide force of the landslide was calculated as 1449.10 kN/m.The anti-slip measures were urgently needed for the slope.Finally,aiming to improve the safety of tunnel construction after landslide treatment,based on the development of the landslide,a scheme of anti-slide pile and back pressure was developed,and a comparison of the scheme was made.Considering the low engineering cost of the anti-slip pile scheme,it was beneficial for the stability of the mountain during operation and had a small impact on the environment.The backfilling and backpressure scheme had high engineering costs,which could induce the occurrence of secondary landslides.The anti-slip pile scheme was chosen and achieved good governance results.