深井分区破裂围岩在爆炸荷载下的含损伤动态本构模型及应力波传播规律

Based on the background of zonal disintegrated rocks instability in deep coal mines of great strata stress in Huainan and Huaibei Coal Mining Areas, focused on damage forms and stress wave propagation in zonal disintegrated surrounding rocks under great strata stress, dynamic mechanical character of zonal disintegration of surrounding rocks at different transverse isotropy and transverse anisotropy, which are caused by blasting, are investigated by using material testing machine, split Hankinson pressure bar(SHPB), light gas gun(LGG), triaxial rock material testing machine, synchrotron radiation light. Anisotropic damage evolution equation and dynamic constitutive relationship are established which include nonlinearity, strain rate effect and damage softening effect. The concise forms and embedded processes suitable for stress wave analysis and numerical calculation are obtained according to established constitutive equations. Aiming at shockwave recognition, elastic-plastic interface tracking and stress wave interaction at different material interface, in the study the theory of singular surface and characteristic theory of stress wave propagation are to be improved and developed. Based on the combination of advantages of characteristic theory, difference method and finite element method, Quasi-Characteristics Algorithm of generalized characteristic theory are obtained to improve high-precision algorithm and format, which improve the recognition accuracy of stress wave propagation and damage effect of zonal disintegration of surrounding rocks. According to the established constitutive relationship of dynamic damage evolution, numerical method, field and laboratory experiments, physical nature of stress wave propagation, attenuation and damage effect can be revealed. Reasonable application of the research results provides a scientific basis for improving basting quality and surrounding rock stability.

以两淮矿区深部高应力矿井分区破裂围岩在爆破荷载下失稳为背景，紧密围绕高应力围岩交替破裂区域在强动荷载作用下的损伤破坏形式和强应力波传播特征，基于霍普金森压杆、岩石三轴实验机、同步辐射光等实验方法，研究爆炸荷载下横观各向同性和正交各向异性分区围岩的动态力学特性，建立反映其非线性效应、应变率效应和损伤软化效应的各向异性含损伤动态本构关系，给出适合应力波分析和数值计算的简明形式和嵌入流程；以冲击波识别、拉压交界面波相互作用和界面跟踪为目标，完善和发展波传播的奇异面理论和特征理论，将特征理论和差分及有限元方法各自优点相结合，建立广义特征理论的拟特征混合算法, 发展高精度算法和格式以提高应力波传播及损伤破坏效应的识别精度。 根据建立的动态损伤本构模型和数值方法结合模型实验、现场试验揭示深井分区破裂围岩中爆炸应力波传播、衰减及破坏效应物理本质，为改善爆破效果和提高围岩稳定性提供科学依据。

进行了不同应变率下的单轴冲击压缩实验，成功采集了实验波形、煤岩破碎程度等数据，利用三波法对原始数据进行处理，得到了煤岩动态应力应变曲线。实验结果表明：煤岩的动态强度、动态弹性模量及破碎程度均具有较强的应变率敏感性，煤岩应力应变曲线表现出显著的应变硬化和应变率硬化等动态力学特性。.采用霍普金森拉杆（SHTB）装置法进行煤岩直接拉伸试验。实验结果表明：在135s-1 ~ 253s-1区间内得出了煤体直接拉伸的应力应变关系；煤体在拉伸荷载作用下存在应变率效应且动态拉伸强度与应变率呈幂函数关系。.针对煤岩的动态力学特性，根据粘弹性理论和损伤力学理论，简化朱-王-唐方程并引入动态损伤因子，建立了较好反映煤岩峰值应力前动态应力应变关系的本构方程。由单轴压缩实验和数据拟合得到全部本构方程的未知参数。. 设计可以实现可控双脉冲加载装置并利用该装置对煤体在重复冲击荷载下的动态力学响应进行了相关实验研究，实验结果表明：煤体是一种应变率相关材料，但随着应变率的升高和破碎强度的增强煤体的应变率效应会逐渐钝化，即中高应变率条件下煤体的动态破碎强度基本维持在90MPa左右；煤体在双脉冲荷载下的动态力学响应与首次脉冲荷载的强度有关，当首次脉冲强度较低时煤体破碎强度会随第二次脉冲作用而升高但应变率会降低，此时第二次冲击时会在前期已有活化裂纹数目的基础上穿过既有裂纹饱和密度向更高裂纹层次发展。当首次脉冲强度较高时，煤体在首次脉冲作用下已经破碎二次脉冲的能量很少能够穿过破碎煤体，此时第二道脉冲荷载只是加速了裂纹在扩展阶段的破裂使得裂纹朝着尺寸更小的方向演化。. 对于C30混凝土，当装药比例埋深为0.25 m/kg1/3≤h≤1.0m/kg1/3时，随着装药比例埋深的增加，爆炸冲击质点加速度峰值随之增大，但加速度随比例埋深的衰减规律基本一致；对于不同强度的混凝土触地爆（h=0m/kg1/3），随着混凝土强度的增大，爆炸冲击质点加速度峰值随之增大，加速度衰减规律基本一致；给出了C30混凝土不同埋深爆炸冲击加速度精度较高的预估公式。