构造应力场作用下覆岩结构演化与冲击地压机理研究

The rockburst is caused by sudden releasing energy, and tectonic stress field and overlying structure evolution are important energy source. The project propose the tectonic movement influence factors combined with the weight and magnitude , and determine the distribution characteristics of the tectonic stress field. According to the triaxial cyclic loading and unloading test, the functional relationship between elastic modulus, poisson's ratio and plastic strain will be determined. Based on the analysis of dynamic boundary condition and constitutive relation , the nonlinear dynamic mathematical-mechanical model of the overburden structure considering the tectonic stress is established. The "interface" unit and the "damage" unit are used to describe the "fissure" and "collapsing rock". The risk of impact rockburst is described by the rockburst impact index. The overlying strata spatial structure evolution numerical model will be established. The influence mechanism of tectonic stress on formation and evolution of overlying strata structure will be analyzed, and the intrinsic relationship between rockburst and tectonic stress and corresponding overlying strata structure feature will be determine. The coal and rock dynamical system of rockburst is put forward, the background energy and the energy trigger condition of the rockburst will be clearly defined. The relationship between the different rock burst failure appearance and the dynamic system dissipative structure characteristics will be studied. The purpose of this project is to elucidate the rockburst induced mechanism of overburden structure evolution under tectonic stress field, and guide the prevention and control of rockburst.

冲击地压源于能量的突然释放，构造应力场和覆岩结构演化是冲击地压重要的能量来源。项目提出构造运动各因素权重与量值相结合的活动构造影响因子，确定煤岩体构造应力场的分布特征；根据三轴循环加卸载试验，确定弹性模量、泊松比与塑性应变的函数关系；基于动态边界条件和本构关系相关分析，建立考虑构造应力的覆岩结构非线性动态数学-力学模型；采用“接触面”单元和“损伤”单元描述开采产生的“裂隙”和“垮落岩层”，采用冲击地压危险指数描述冲击地压的危险性，建立覆岩空间结构演化的数值模型；分析构造应力对覆岩结构形成和演化的影响机制，确定构造应力及其相应的覆岩结构特征与冲击地压失稳的内在联系；提出冲击地压的煤岩动力系统，明确冲击地压发生的背景能量以及煤岩动力系统失稳的能量触发条件，研究不同动力显现特征与煤岩动力系统耗散结构演化之间的内在联系。旨在阐明构造应力场下覆岩结构演化的诱冲机制，指导冲击地压的防治工作。

诱发冲击地压弹性变形势能来源主要为两个方面，即现代构造运动和人为开采扰动。现代构造运动产生的巨大能量，经过逐级传递将传入井田范围内，使煤岩体的构造应力和能量升高。而开采扰动下形成覆岩结构对采动应力和能量的分布具有重要影响。在高构造应力环境的影响下，坚硬顶板控制下的覆岩结构使得岩体应力高度集中，二者共同作用下易诱发冲击地压等矿井动力灾害。项目研究了构造运动对煤岩体应力分布的影响作用，确定了构造运动影响下煤岩体构造应力场的分布特征。建立了工作面回采过程的覆岩结构模型，研究了开挖过程的覆岩结构动态变化与失稳过程的煤岩体应力场和能量场的演化规律。分析了不同构造应力场作用下覆岩结构顶板垮落特征和覆岩位移演化规律，确定构造应力对覆岩结构形成和演化的影响机制。确定冲击地压发生的能量触发条件，分析了不同动力显现特征与煤岩动力系统耗散结构演化之间的内在联系。分析了工作面开采过程的覆岩结构和采动应力演化规律，预测冲击地压的发生位置和强度，提出冲击地压的防治方案.本项目的研究，不仅对冲击地压机制和机理具有重要理论意义，而且能够为冲击地压危险性的预测及预警防治对策的系统研究提供理论基础和科学依据。