采动应力与采空区压实承载耦合分析方法研究

采空区垮落带在覆岩沉降作用下的应力恢复对采动应力场有显著影响。基于围岩应力与采空区压实承载的耦合作用,研究了垮落带岩体压实承载的力学特性及参数反演方法,分析了裂隙带岩体的拉伸劣化力学特性,提出了采动应力场与采空区压实承载耦合分析方法,通过实例仿真模拟分析进行了验证。研究表明:垮落带渐进压实承载的力学特性是指数型表达式,压缩刚度随压缩应变呈非线性增长。由双屈服本构模型反演得到与理论解拟合度较好的垮落带力学参数,实现了垮落带压实承载特性的仿真模拟。裂隙岩体劣化系数表达式反映了模量劣化特性,应变软化本构模型增加模量劣化算法组成岩体劣化本构模型,实现了应变软化和裂隙岩体模量劣化的动态分析,较真实严谨的反映裂隙带岩体的力学特性。基于垮落带与裂隙带特征的仿真模拟,实现了采动应力场与采空区覆岩"两带"特征的耦合分析。通过工作面支承压力场演化特征的实例仿真分析,验证了采动应力场与采空区压实承载耦合分析方法的可行性和正确性,提高了采动应力场和围岩采动响应研究的严谨性和可靠性。

Numerical simulation on coupling method between mining induced stress and goaf compression

The goaf stress recovery under the effect of overlying strata subsidence has notable effect on mining induced stress field.Based on the coupling effect between ground stress and goaf compression，the mechanical characteristics and properties back analysis method of caved rock are studied，the tension weakening characteristics of rock mass in fractured zone are analyzed，and hereby the coupling simulation method between mining induced stress and goaf compression is proposed and verified using a simulation case study.The results show that the mechanical behavior of the compressed caved zone follows an exponential growth，the compression stiffness nonlinearly increases with the compression strain.The mechanical properties of caved zone obtained from back analysis agree with the analytical results，which contribute to the simulation of the mechanical behavior of goaf.The tension weakening model，which is developed from strain softening model by adding the tension weakening algorithm，can describe the weakening of Young’s modulus，hereby achieve to describe the mechanical behavior of fractured rock mass rigorously.Based on the mechanical behavior simulation of caved and fractured zone，the proposed method can conduct the coupling numerical simulation of mining induced stress field and the overlying “two zone”.