论文部分内容阅读
在砂砾石地层中,围岩土体及隧道结构的变形与力学行为主要受控于开挖扰动程度及开挖扰动范围内块石细观结构的影响.结合土石混合体的细观结构分布特征,基于尺度分离与尺度耦合相结合的思想,提出了砂砾石地层隧道开挖多尺度分析方法及分析模型,继而对该分析方法中的3个关键问题,即核心区域与非核心区域的划分,核心区域内关键粒径的确定及土石混合体宏观等效物理力学参数的确定方法进行了探讨.该多尺度分析方法的基本思想是:将砂砾石地层隧道开挖模型划分为核心区域与非核心区域,在核心区域内从细观上考虑土石混合体的分布特征,在非核心区域将土石混合体视为宏观均质材料,在此基础上进行砂砾石地层隧道开挖的宏细观模拟与分析.采用该分析方法对砂砾石地层隧道开挖过程进行了多尺度模拟,从围岩土体变形与围岩压力两个角度,与砂砾石地层隧道开挖细观分析模型及宏观分析模型得到的结果进行了对比,发现本文多尺度分析方法与细观分析模型的结果吻合较好,验证了多尺度分析方法的有效性,且该方法大大减少了计算量与建模工作量,提高了计算效率.
In sand and gravel stratum, the deformation and mechanical behavior of surrounding rock mass and tunnel structure are mainly controlled by the degree of excavation disturbance and the influence of rock mass mesostructure within the excavation disturbance range.Combined with the distribution characteristics of meso-structure of soil-rock mixture Based on the idea of combining scale separation and scale coupling, a multi-scale analysis method and analysis model for tunnel excavation in gravel stratum are proposed. Then three key problems in the analysis method, namely, the division of core area and non-core area, The determination of the key particle size in the core region and the determination method of macroscopic equivalent physical and mechanical parameters of the soil-rock mixture are discussed.The basic idea of this multi-scale analysis method is that the tunnel excavation model of sand and gravel stratum is divided into core area and non-core In the core area, the distribution characteristics of the soil-rock mixture are considered in the meso-scale, and the soil-rock mixture is regarded as the macroscopically homogeneous material in the non-core area. Based on the analysis, the macroscopic and microcosmic simulation of tunnel excavation in gravel stratum and This method is used to simulate the tunnel excavation process in gravel stratum. From the perspectives of deformation of surrounding rock and surrounding rock pressure, The comparison of the results obtained by the macroscopic analysis model and the results obtained by the macroscopic analysis model shows that the multi-scale analysis method in this paper is in good agreement with the results of the mesoscopic analysis model, and the validity of the multi-scale analysis method is verified. Greatly reduce the amount of computation and modeling workload, improve the computational efficiency.