隧道衬砌背后空洞上方落石对衬砌结构的破坏机理及整治措施

Study on Failure Mechanism and Renovation Measures of Lining Structure Influenced by Falling Rocks Above Cavity Behind the Tunnel Lining

针对某铁路隧道衬砌出现的掉块病害进行了现场勘查以及三维激光扫描,并对隧道衬砌掉块的成因进行了分析。引入混凝土冲切破坏理论计算方法,估算了衬砌抗冲切承载力。同时,借鉴国内外落石冲击力理论、经验计算方法并利用LS-DYNA动力学软件建立了落石冲击衬砌结构动力学分析模型,对落石冲击作用下衬砌结构的破坏机理进行了分析。结果表明:不同方法计算的落石冲击力与有限元分析所得的冲击力差异较大,这主要是因为各种计算方法的试验条件、理论基础不同;衬砌背后空洞上方的落石冲击衬砌时,在短时间内冲击荷载将达到峰值,易导致衬砌结构发生冲切破坏。针对该隧道状况,通过方案比选,提出了预制拼装波纹板的整治技术。

A field investigation and the 3D laser scanning were made for the falling block diseases of one railway tunnel lining,the causes of falling blocks in tunnel lining were analyzed,the punching shear resistance carrying capacity oflining was estimated by introducing the calculation method of concrete punching shear failure theory,a dynamic analysis model of falling rocks impacting the lining structure was established by using LS-DYNA dynamics software based on domestic and foreign theory and the experience calculation method of falling rocks impact force theory,and the failure mechanism oflining structure under action of falling rocks was analyzed. The results showthat the impact force of falling rocks calculated by different methods is different from that calculated by finite element analysis due to the different experimental conditions and theoretical basis of various calculation methods,the impact load will reach the peak value which will lead to the punching shear failure of the lining structure in a relative short time when the lining was impacted by the falling rocks above cavity behind the tunnel lining. According to the condition of the tunnel,this paper put forward the renovation technique of the prefabricated assembled corrugated plate through scheme comparison.