隧道穿越溶洞及断层突水机理与防控对策研究

Study on Water Inrush Mechanism and Prevention and Treatment Measures of Tunnel Crossing Karst Area and Fault Zone

硬质岩地区的岩溶区和断层带突水防治的关键在于突水判据的建立。先从理论研究出发,以材料力学、结构力学和理论力学为基础,建立了“有效隔水岩层(柱)”的突水力学结构模型;采用了构建函数的方法,得到了“有效隔水岩层(柱)”的总势能函数表达式;基于突变理论,构建了岩溶区及断层带突水的尖点突变模型,获得了“有效隔水岩层(柱)”厚度、长度、水压力及岩石力学参数之间的函数关系;基于断裂力学,建立了一种硬质岩地区的岩溶区和断层带突水损伤力学判据,并以正在施工的广西某隧道为例,开展了应用研究,提出了隧道穿越硬质岩地区的岩溶区及断层带突水防控对策。结果表明:突水临界厚度值按计算突水临界厚度值的1.5倍取用,能较为有效地指导施工,验证了理论方法较为合理;提出的岩溶区或断层带突水防控对策,为解决隧道岩溶区和断层带突水问题提供一种新的理论支持。

The key of water inrush prevention in karst area and fault zone in hard rock area lies in the establishment of water inrush criterion.A water inrush mechanical structural model of"effective water-resisting rock(column)"was established based on material,structural,and theoretical mechanics.By using the method of constructing function,the total potential energy function expression of"effective water-resisting strata(columns)"was obtained.Based on catastrophe theory and the expression form of total potential energy function,the cusp catastrophe model of water inrush in karst area and fault zone was constructed.The functional relationship among the thickness,length,water pressure and rock mechanics parameters of"effective water-resisting strata(columns)"was obtained.Based on fracture mechanics,the mechanical criterion of water inrush damage in the karst area and fault zone was established.Tunnel under construction in Guangxi was taken as an example to study,according to the geological and hydrogeological conditions of the tunnel,the prevention and control measures of water inrush in karst area and fault zone where the tunnel through hard rock area were put forward.The research results show that:The critical thickness of water inrush was 1.5 times of the calculated critical thickness of water inrush,which can effectively guide the construction and verify that the theoretical method was reasonable.The prevention and control measures of water inrush in karst area or fault zone are put forward,which had certain guiding significance for construction and provides a new theoretical support for solving the problem of water inrush in karst area and fault zone of tunnel.