隧道与溶洞间复合围岩抗水压能力数值模拟研究

针对平行导洞扩挖施工导致隧道与溶洞间围岩安全厚度不足问题，将围岩与注浆结石体、衬砌结构与注浆结石体视为复合围岩，采用岩石真实破裂过程分析软件（Rock Failure Process Analysis, RFPA）软件对复合围岩破裂突水演化过程进行数值模拟，探讨了不同厚度和类型复合围岩的抗水压能力。结果表明：复合围岩破坏分为外层注浆结石体破坏和内层围岩破坏两个阶段；围岩、注浆结石体厚度越大，复合围岩抗水压能力越高；施作初期支护和二次衬砌将显著提升复合围岩抗水压能力，当二次衬砌厚度为1.2 m时，抗水压能力可提高至4.44 MPa，为新圆梁山隧道穿越2#溶洞施工合理选择临时二次衬砌参数提供依据。

Numerical simulation on water pressure resistance of composite surrounding rock between tunnel and karst cave

In view of the insufficient safety thickness of surrounding rock between tunnel and karst cave due to parallel pilot tunnel expansion excavation, the surrounding rock and grouting-reinforced rock mass, lining structure and grouting-reinforced rock mass are regarded as composite surrounding rock respectively. Numerical simulation on the evolution process of water inrush due to composite surrounding rock failure is analyzed by using Rock Failure Process Analysis (RFPA) software. The water pressure resistance of different thickness and types of composite surrounding rock are discussed. The results show that the failure of the composite surrounding rock can be divided into two stages, that is, outer grouting-reinforced rock mass failure and inner surrounding rock failure. The larger the thickness of surrounding rock and grouting-reinforced rock mass, the higher the water pressure resistance. Initial support and secondary lining can significantly improve the water pressure resistance of composite surrounding rock. When the thickness of the secondary lining is 1.2 m, the water pressure resistance of composite surrounding rock is 4.44 MPa. which The result provides a basis for the reasonable selection of temporary secondary lining parameters when the New Yuanliangshan tunnel passed through the No.2 karst cave.