隧道塌方机制及其影响因素离散元模拟

通过文献查阅及现场调研,统计分析了大量公路、铁路隧道和水工隧洞塌方工程实例,对隧道塌方进行了分类,认为地质条件、隧道埋深、隧道断面形式及大小、地下(表)水、爆破扰动、施工措施不当是隧道塌方的主要影响因素,并采用隧道塌方高度、隧道埋深、地表陷穴宽度等与隧道跨度的比值以及破裂角作为表征隧道塌方程度的参量,全面分析了上述因素对隧道塌方的影响。通过与统计资料塌方量的对比,分析了几种常用隧道松动荷载计算方法的适用性。文中最后运用PFC2D程序模拟了隧道塌方的全过程,分析了隧道塌方影响因素对隧道塌方发生机制的作用,取得了与统计分析相一致的结论。

Tunnel collapse mechanism and numerical analysis of its influencing factors

A large number of engineering facts of tunnel collapse were stated and analyzed through consulting references and field investigation.Through the analysis of the statistical materials,a new classification scheme was proposed,and geological condition,buried depth,form and size of cross section,ground water,blasting disturbance and incorrect construction measures were considered as the main influencing factors of the tunnel collapse.The contributions of these factors to the tunnel collapse were analyzed comprehensively while the ratio of collapse height,buried depth,width of surface subsidence to tunnel span and angle of rupture were taken as the parameters indicating the degree of collapse.The applicability of some calculating methods for determining surrounding rock pressure was studied through the comparison with the statistical materials.The whole process of tunnel collapse was simulated by PFC2D.The contribution of the influencing factors to the tunnel collapse was studied through the results of the numerical simulation which matched the results of statistical materials perfectly.