破碎煤岩高分子材料注浆固结体流变特性与破坏机理研究

Polymer material grouting has achieved good results in mining surrounding rock control under severe conditions. Influenced by harsh geomechanics conditions and mining induced stress, part of the roadways in deep coal mines show large deformation and rheological behavior even with grouting support. The rheology of grouted surrounding rock have become an important factor affecting the stability of some soft rock roadways. In this project, coal and rock grouting geocomposite creep experiments will be conducted to obtain the mechanical properties, deformation laws, and viscoelastic-plastic strain characteristics at different creep stages. Coal and rock grouting geocomposite shear creep experiments will be carried out to study the creep mechanical properties and deformation laws of the cemented fracture surface at different creep stages. This project will combine theoretical analysis with laboratory testing, from the perspective of the combination of meso and macro, to obtain the mechanism of creep damage of grouting geocomposite. The relationship between the anisotropic characteristics and the nonlinear mechanical response mechanism of grouting geocomposite during creep failure will be revealed. The damage initiation mechanism under different failure modes will be analyzed, and the relationship between fracture evolution and macroscopic deformation failure will be studied. A non-linear constitutive model of grouting geocomposite can be established. The grouting geocomposite creep calculation module in discrete element software will be developed. The CT scan image will be used to accurately construct the three-dimensional numerical model of the grouting geocomposite for numerical simulation. Therefore, the constitutive model and the calculation module can be verified and improved. The project results can provide a scientific basis for grouting reinforcement of polymer materials in deep soft rock roadways.

高分子材料注浆在困难条件下的围岩控制中取得了良好的效果。在深部地质力学环境及采掘扰动影响下，部分巷道注浆加固后，仍呈现出大变形特征和显著的流变特性。注浆围岩的流变已经成为影响部分软岩巷道稳定性的重要因素。本项目拟研究蠕变不同阶段注浆固结体蠕变的力学性质、变形规律、弹粘塑性应变特征；测试分析蠕变不同阶段胶结裂隙面的蠕变力学性质、变形规律。综合理论分析与实验室测试，从细观和宏观相结合的角度，揭示蠕变破坏过程中固结体各向异性特征与非线性力学响应机制关系、分析不同破坏模式情况下的损伤起裂机制、研究破裂演化与宏观变形破坏的关系，得出固结体蠕变破坏机理。建立注浆固结体蠕变非线性本构模型，开发离散元软件中注浆固结体蠕变计算模块，利用CT扫描图像精准构建固结体三维数值模型并进行数值模拟，以验证并改进本构模型及计算模块。项目研究成果可以为深井软岩巷道高分子材料注浆加固提供科学依据。

高分子材料注浆在困难条件下的围岩控制中取得了良好的效果。在深部地质力学环境及采掘扰动影响下，部分巷道注浆加固后，仍呈现出大变形特征和显著的流变特性。注浆围岩的流变已经成为影响部分软岩巷道稳定性的重要因素。研究破碎煤岩高分子材料注浆固结体的流变特性、分析注浆固结体破坏机理，对深井巷道围岩控制具有重要意义。本项目中制作破裂砂岩注浆固结体试件，测试破碎煤岩及其注浆固结体的各项基本力学参数，对比分析注浆加固对破碎煤岩力学参数的提高效果。研究结果表明随着围压的增大，破碎砂岩注浆固结体的本构模型由应变软化向应变硬化过渡，呈现出典型的延性破坏特征。试件内部裂隙衍生、发育与延展节点同声发射累计能量计数的变化节点对应。基于声发射能量计数，推导出了破碎砂岩注浆固结体试件损伤变量，损伤变量曲线与应力应变曲线、体积应变曲线和能量演变有着良好的对应关系。对破裂砂岩注浆固结体试件进行CT扫描，通过处理得到注浆固结体试件内部的浆液与裂隙模型，导入FLAC3D中进行数值模拟试验，分析注浆固结体试件破坏机理。数值试验中注浆固结体试件破裂方式与声发射空间定位结果一致，试件沿浆液裂隙面发生剪切破坏。在三轴压缩蠕变实验的基础上，采用不同的蠕变本构模型，对完整砂岩和破碎砂岩注浆固结体试样的实验结果进行了拟合。Burgers模型比广义Kelvin模型更为准确地描述砂岩及其注浆固结体瞬时弹性变形、衰减蠕变以及等速蠕变变形，能够有效的反映不同围压下砂岩注浆固结体黏弹性蠕变特征。引入了一种能够表征试样加速蠕变阶段的非线性蠕变模型，同Burgers模型进行串联组成新的黏弹塑性模型，用新的蠕变本构模型对试样非线性蠕变阶段进行了拟合，并对参数进行辨识，获得了较好的拟合效果。本课题研究成果对深井软岩巷道高分子材料注浆加固技术具有理论价值和实践意义。