岩溶隧道衬砌结构抗水压能力足尺模型试验研究——以新圆梁山隧道工程为例

Full-Scale Model Tests on Water Pressure Resistance of Karst Tunnel Lining Structure:a Case Study of New Yuanliangshan Tunnel

为验证新圆梁山隧道穿越高压富水岩溶地层时衬砌结构的抗水压能力,提出一种隧道衬砌结构抗水压足尺模型试验方法,将隧道衬砌承受的外水压力问题转换为隧道衬砌承受内水压力问题进行研究。通过岩石破裂过程分析系统开展数值仿真计算,给出不同尺寸和加载方式下衬砌模型抗水压安全系数的换算关系。最后,设计并开展新圆梁山隧道衬砌结构抗水压值足尺模型试验。结果表明:1)隧道衬砌结构在承受外部均布水压和局部水压时的极限抗水压值分别为足尺模型试验极限抗水压值的1.44倍和0.67倍;2)新圆梁山隧道溶洞过渡段衬砌(K2.0型衬砌)的抗水压能力为3.33 MPa,溶洞核心段衬砌(K3.0型衬砌)的抗水压能力不低于5.33 MPa,说明新圆梁山隧道采用K3.0型和K2.0型衬砌施工缝防水构造是合理的,衬砌结构的抗水压能力满足设计要求。

A full-scale model test method for water pressure resistance of lining structure is proposed for New Yuanliangshan tunnel passing through high-pressure water-rich karst areas.To validate the water pressure resistance of the tunnel lining structure,the external water pressure born by tunnel lining is transformed into internal water pressure.Then through numerical simulation results using realistic failure process analysis(RFPA)system,the conversion relation of different models′hydraulic safety factors is established.The results show the following:(1)The ultimate hydraulic resistance of tunnel lining structure under external uniform water pressure and local water pressure is 1.44 and 0.67times of the ultimate hydraulic resistance of full-scale model test,respectively.(2)The water pressure resistance of karst cave transitional section lining(K2.0)is 3.33 MPa,and that of the karst cave section lining(K3.0)is no less than 5.33MPa,indicating the K2.0 and K3.0 lining of construction joints is reasonable for New Yuanliangshan tunnel,and meeting the water pressure resistance of the design requirements.