斜井冻结壁力学特性及设计理论研究

For purpose of getting the change law of stresses and displacements for frozen wall during excavation in inclined shaft, the combination of theoretical analysis, physical experiment and numerical simulation methods will be used based on unloading effect, and the elastic and elastic-plastic analytical solution will be worked out, and getting the variation of deformation in frozen wall by adapting existed field construction parameters. Through theoretical analysis, the theoretical model considering the interaction of circular and irregular frozen wall and ground subjected to non-uniform stresses will be built, basing on unloading effect, the elastic and elastoplastic analytical solutions of stresses and displacements in frozen wall and ground will be obtained, as well as the design formula of frozen wall thickness and the distribution of plastic zone in froze wall. Taking weathered sandstone and mudstone in western region as research objects, the stress-displacement curve of frozen soft rock will be worked out, as well as the deformation and failure regularities under the condition of step unloading lateral stress with constant axial stress, and the condition of step unloading axial stress with constant lateral stress, respectively. By building experiment model close to the practical frozen construction engineering in inclined shaft, and conducting orthogonal design tests considering different factors, analyze the deformation regularities of frozen wall under excavation, and obtain the regression relation among deformation of frozen wall and parameters of frozen wall design and shaft construction.

为了获得斜井冻结法凿井施工中冻结壁的应力和位移变化规律，采用理论分析、物理试验和数值模拟相结合的方法，研究开挖卸载效应下冻结壁的应力和位移场分布规律，给出冻结壁弹性、弹塑性设计理论，并结合现有现场参数，获得冻结壁变形规律。通过理论分析，建立非均匀荷载作用下圆形和非圆形冻结壁与围岩相互作用模型，基于开挖卸载效应，获得冻结壁和围岩的应力和位移场的弹性和弹塑性解析解，给出冻结壁厚度设计理论以及冻结壁塑性区的分布规律。以西部风化砂岩和泥岩为主要研究对象，进行三轴卸载试验，分别研究“恒轴压卸围压”、“恒围压卸轴压”两种不同卸载路径下冻结软岩的变形本构关系，岩样变形破坏机理。建立与实际斜井冻结凿井工程相接近室内试验模型，进行不同因素正交组合试验，分析开挖过程中冻结壁的变形规律，获得冻结壁变形与冻结壁设计参数、井筒施工参数等因素之间的回归关系。

采用理论分析、物理试验和数值模拟相结合的方法，获得了斜井冻结法凿井施工中冻结壁的应力和位移变化规律，得到了开挖卸载效应下冻结壁的应力和位移场分布规律，给出了冻结壁弹性、弹塑性设计理论，并结合现场参数，获得冻结壁变形规律。通过理论分析，建立了非均匀荷载作用下圆形和直墙半圆拱形斜井冻结壁与围岩相互作用模型，基于开挖卸载效应，获得了冻结壁和围岩的应力和位移场的弹性和弹塑性解析解，给出了冻结壁厚度设计理论以及冻结壁塑性区的分布规律。在实验室建立了适用于斜井加载-冻结-掘砌模型试验的三维模拟试验系统，分析获得了掘砌过程中冻结壁的温度场和变形规律，获得了冻结壁温度场、变形与各影响因素之间的回归关系。采用数值模拟方法，建立了弹塑性、粘弹塑性冻土模型，开展了冻结壁温度场和变形规律的单因素和正交分析，获得了各影响因素单独变化和综合变化下，冻结壁的厚度和变形规律，并对试验结果进行补充验证。以西部风化砂岩及固结冻土为主要研究对象，进行了低温单、三轴试验和动态霍普金森杆冲击试验，分别研究了不同加载路径下冻结软岩和固结冻土的应力-应变关系和变形破坏规律。获得了不同含水率、冻结温度、围压等因素下冻结软岩和固结冻土的强度和变形特性，分析了冻结软岩和固结冻土的耗散能演化规律。