富水板岩隧道围岩泥化临界判据研究

Under the influence of groundwater, argillization of surrounding rock in slate tunnel will happen. However, the current specification on lining structure design and surrounding rock deformation calculation in water-rich slate tunnel regarded two kinds of state (before and after argillization) as one state and ignored the influence of argillization. The project takes Yaojia tunnel in Shanghai-Kunming Passenger Dedicated Line Chang-Kun Hunan Section as the engineering background and slate as the research object. The argillitization evolution of slate mineral content, microstructure and pore geometry is explored using mico-meso test. The argillitization swelling constitutive equation is established, and the evolution characteristics of the plasticity index and the particle size for disintegration product in the mudding process is researched based on hydro-physical test. The degradation effect of the hydro-chemical parameters, water pressure, water absorption and the structural plane occurrence on the mechanical parameters is studied, and the influence of stress path on slate argillitization is analyzed through triaxial compression test and water-rock chemical experiment. Then the catastrophe and chaos theory are used to establish the argillitization critical model of surrounding rock in water-rich slate tunnel, providing the basis for revising calculation of lining structure and surrounding rock deformation in water-rich slate tunnel.

在地下水的影响下，板岩隧道围岩会发生泥化作用，然而目前规范中在对富水板岩隧道进行衬砌结构设计和围岩变形计算时，将泥化前后两种状态视为一种状态，忽略了泥化的影响。课题以沪昆客运专线长昆湖南段姚家隧道为工程依托，以板岩为研究对象，借助微细观试验探寻板岩矿物成分、微观组构和孔隙结构的泥化演变规律；基于水理性试验建立板岩泥化膨胀本构方程及研究其泥化过程中崩解产物塑性指数和颗粒粒度的变化特征；通过三轴压缩和水岩化学试验研究水化学参数、水压力、吸水率和结构面产状对板岩力学参数的劣化效应，分析应力路径对板岩泥化的影响。在此基础上运用突变理论和混沌理论建立富水板岩隧道围岩泥化临界模型，为修正计算富水板岩隧道衬砌结构和围岩变形提供依据。

在地下水的影响下，板岩隧道围岩会发生泥化作用，然而目前规范中在对富水板岩隧道进行衬砌结构设计和围岩变形计算时，将泥化前后两种状态视为一种状态，忽略了泥化的影响。针对富水板岩隧道围岩泥化问题，项目以沪昆客运专线长昆湖南段姚家隧道为工程依托，以板岩为研究对象，采用电镜扫描、核磁共振及压汞试验，得出了板岩矿物成分、微观组构和孔隙结构的泥化演变规律。基于膨胀特性试验建立了板岩泥化膨胀本构模型，该模型考虑了时间因子，以最大体积膨胀率对应的时间为临界泥化膨胀时间，当吸水时间小于或等于临界泥化膨胀时间时，体积膨胀率服从含时间效应的三维膨胀本构模型；当吸水时间大于临界泥化膨胀时间时，体积膨胀率不再服从本构模型，等于定值（最大体积膨胀率）。通过单轴压缩和水岩化学试验得出了板岩力学特性发生改变的临界时间点，并得出了吸水率对单轴抗压强度和弹性模量等力学参数的劣化效应。以非线性分析与物理反演分析理论为基础，建立了考虑板岩孔隙形状分维值、孔隙度、单轴抗压强度和弹性模量等影响因素的板岩泥化演变物理化学模型，该模型可较好的预测板岩在泥化过程中微观结构和力学参数的演变规律。该项目通过三年研究，发表论文6篇，其中EI检索4篇，出版专著1部。