采动岩体破损力学行为演化与三维动态裂隙形态表征

In mining rock mass, the micro- and the macroscopic states are difficult to observe and quantify. And the mining rock mass internal structure as well as the intrinsic mechanism by which the apparent mechanical behavior of mining rock mass is governed are also hard to correctly and/or vividly capture or quantificationally characterize. The objective of this research project is to study theoretically and experimentally the rock mass scale effect in experiments, and the methods for the visualized and the quantitative representations of the three-dimensional (3D) damaging state within mining rock mass, based on a mining rock mass engineering. Detailed description of the research project plan is presented below. Firstly, by using the borehole television (BTV) technique, the fracturing accumulation and evolution characteristics and the dynamic damaging process are to be analyzed so as to capture the inherent mechanism controlling rock mass progressive damaging evolution. Secondly, based on the DIC technique, identifying, extracting and quantification of the key parameters used to characterize the rock mass two-dimensional (2D) CT damaging process will be performed. This performance, then, will facilitate the proposal of an effective method for identifying and quantifying the rock mass internal damaging structure. Thirdly, it is going to develop the numerical computed tomography (NCT) technique, and to establish a 3D reconstruction (3DR) model for the spatial distribution of the key parameters used to characterize the rock mass 2D damaging process. The established 3DR model exhibits vividly and quantificationally the spatial form characteristics of rock mass internal complex structure. Lastly, it is about to build a quantitative relation between the macroscopical physical quantities and the micro- and macroscopic evolutionary mechanical effects, and to proposal a method for the reconstruction and representation of the spatial distribution form of rock mass internal characteristic parameters. The established models and methods will be challenged by the results from analyzing the fracturing evolution characteristics of the considered mining rock mass, which is expected to further refine these models and methods. This research project is significant for the developments of the cross-scale numerical analysis method, the rock mass failure theory, and the crack-morphology representation method. The research results are beneficial to the design optimizing of rock mass engineering.

采动岩体内部细-宏观状态难以观测和量化、内部结构以及对表观物理力学行为起控制作用的内禀机制无法直观准确展示和定量表征。本项目以开挖扰动岩体工程为背景，特色在于关注岩体实验尺度效应、结构内部破损状态三维直观展示与定量表征问题，联合试验和理论开展研究。采用BTV技术，分析裂纹累积演化特征和破损动态发展过程，揭示岩体渐进破损演化内在力学机理；基于DIC技术，对岩体二维CT破损关键特征参量进行辨识、提取和量化，提出岩体内部破损结构辨识与量化方法；发展NCT技术，构建岩体破损关键特征参量空间分布3DR模型，直观、定量展示内部复杂结构空间形态特征，建立宏观可测物理量与细-宏观演化力学效应的定量关系，提出岩体内部特征参量空间分布形态重构与表征方法；基于案例工程的采动岩体裂隙演化分析，验证和完善成果。研究成果将有益于完善跨尺度数值分析方法、岩体破坏理论、裂隙形态表征方法等，可为工程设计方案优化提供参考。

开挖、爆破震动等工程扰动作用往往引起岩体结构破损，强度进一步弱化，对工程结构稳定性造成不利影响。针对采动岩体内部细-宏观状态难以观测和量化，及对表观物理力学行为起控制作用的内禀机制无法直观展示和定量表征等问题。本项目在拉正压负和主应力次序σ1 ≤ σ2 ≤ σ3（ε1 ≤ ε2 ≤ ε3）条件下，推导了Mohr-Coulomb屈服接近度表达式，得到了用主应变表示的塑性剪应变和极限塑性剪应变的表达式，为破坏接近度计算提供关键判据，完善破坏接近度理论。同时，基于数字图像处理、数值仿真及三维重构等技术，提出了一种数值层位技术，通过对指定数值层位剖面图的损伤区域进行图像辨识和量化，重构岩体内部损伤的三维形态。并将该理论和方法应用于数值实验和工程案例，三维重构工程岩体和岩石试样的内部破损区域，直观展示破损特征参量的空间形态。研究成果对于发展岩体三维细-宏观跨尺度数值分析方法、完善工程岩体破坏理论等具有较好的理论价值，并对于设计和制订井巷、隧洞、硐室、坡体等不良工程地质体的优化加固参数与方案等，具有较强的工程指导意义。