基于热-水-力-损伤耦合数值模型的高地温水工高压隧洞围岩承载特性  

Load-bearing characteristics of surrounding rock of hydraulic tunnels under high temperature and hydraulic pressure conditions using coupled thermo-hydro-mechanical-damage numerical model

作　　者：苏国韶[1,2] 秦子华 彭立锋[1,2] 邹亚峰 胡小川[1,2] 

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004

出　　处：《岩土力学》2018年第1期308-319,330,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51369007)~~

摘　　要：针对高地温水工高压隧洞围岩的力学行为特点,在考虑岩体的渗透系数、热传导系数随岩体损伤发生变化的基础上,基于多物理场耦合理论,提出一种考虑硬岩强度力学参数劣化的含损伤演化的热-水-力-损伤耦合模型,并给出了该模型的FLAC3D数值实现方法。通过与物理模型试验结果对比,验证了模型的可靠性,进而利用该模型推演了高地温水工高压隧洞的多物理场耦合演化过程,分析了不同影响因素下的承载特性。研究结果表明:隧洞充水运行后,高地温水工高压隧洞的多场耦合效应显著,尤其高地温梯度和高内水压力联合作用下产生的迭加拉应力对围岩的承载安全具有不利影响;温度梯度、内水压力以及岩体线膨胀系数越大,隧洞围岩的损伤程度与开裂深度越大;当隧洞横断面的侧压力系数趋向于1时,洞周出现的宏观裂缝较多,且出现方位不确定;当隧洞横断面侧压力系数小于1/3时,洞周出现的宏观裂缝相对较少,且主要出现在与初始地应力的最大主应力方向相平行的方向上。常规锚喷支护对高地温水工高压隧洞的加固效果不佳。To reveal the mechanical behavior characteristics of surrounding rock of hydraulic tunnels under high temperature and hydraulic pressure conditions, this paper proposes a coupled thermo-hydro-mechanical-damage （THMD） model which considers change of hard rock strength parameters involving damage evolution based on multi-field coupling theory with permeability coefficient and heat transfer coefficient varying with rock damage. The implementation of THMD numerical simulation is conducted by the FLAC3u soRware. The model is proved to be feasible by validation of a physical modeling test, and then the THMD model is employed to deduce the evolution process of multi-field coupling of hydraulic tunnels with high temperature and hydraulic pressure. The evolution process is used to analyze the load-bearing characteristics influenced by different factors. The multi-field coupling effects are very significant in hydraulic tunnels with high temperature and hydraulic pressure after water-filling operation. The complex tensile stress generated by combined load of high temperature gradient and hydraulic pressure contributes to adverse impacts on safe performance of surrounding rock. The damage and crack depth of surrounding rock are larger if the temperature gradient, hydraulic pressure and thermal expansion coefficient are larger. If the lateral pressure coefficient is close to 1, more cracks around the tunnel with random directions tend to form. If the lateral pressure coefficient is less than 1/3, fewer cracks appear around the tunnel and the directions of the cracks are mostly parallel to the direction of the maximum initial stress. The general bolt-shotcrete support does not have good performance in reinforcement of hydraulic tunnels.

关 键 词：岩石力学 水工隧洞 高地温 多场耦合 数值模拟 

分 类 号：TV314[水利工程—水工结构工程]