松散承压含水层下采煤的流固耦合模型试验与 数值分析研究

以松散承压含水层水下采煤为例，通过研制的新型流固耦合相似材料和突涌水物理模拟试验系统真实再现采区突涌水的灾变演化过程，采用光纤光栅技术、声发射技术和电阻率层析成像技术，全程捕捉隔水层围岩应力场、位移场、渗流场、温度场、电场和声发射信息的变化特征及其异常信号，研究突水前兆多元信息的演化规律及其临突特征。采用可考虑多场耦合效应的数值分析方法，研究突水灾变演化过程中应力场、位移场和渗流场的耦合演化规律，分析突水前兆多物理场信息的响应特征。试验和数值分析结果表明：在隔水层破断突水前，围岩应力变化持续增长后发生回跌，但已濒临突水。围岩位移变化持续增长后发生跳跃，在跳跃前出现孕育突水前兆的稳定突升段。围岩渗透压力变化持续降低后发生急剧跌落，在突水前很长时间里出现孕育突水前兆的异常波动段。围岩视电阻率和声发射能量也在突水前产生明显的突升和激增现象，尤其是视电阻率突升段的增长点出现在突水前较长的时间段。通过对多场信息变化规律的内在联系及其对突水预测的有效性分析，发现隔水层的渗透压力、视电阻率以及位移变化信息在突水前具有明显的前兆特征，是松散含水层开采突水灾害预警和监测的重要前兆信息源。研究结果有助于加深对煤矿突水灾变演化过程的认识，为突水前兆信息演化规律及实时监测理论的建立提供科学依据。

Numerical analysis and fluid-solid coupling model tests of coal mining under loose confined aquifer

To study the stability of coal mining under loose confined aquifer, fluid-solid coupling model technology is newly developed, and an extensible geomechanical model system under stress and seepage loading is established. Major improvements in the tests are made in terms of similar materials of fluid-solid and advanced measurement methods/techniques. By using the new similar materials of fluid-solid, true reappearance of catastrophe evolution process for the water inrush induced by mining disturbance is obtained, and multivariate precursor information for real time water inrush is collected by means of the fiber bragg grating technology, acoustic emission technique and resistivity tomography technology. A numerical method considering the coupling effect of multi-physics field is adopted in order to know the coupling evolution law of stress field, displacement field and seepage field in the catastrophe evolution process of water inrush and the response characteristics of precursor information for multi-physics field of water inrush are analyzed. Based on the results of model test and numerical simulation, rock stress suddenly decreases after sustainable growth when the water-resistant key strata rupture, and rock displacement suddenly jumps after sustainable growth, but there exits a stable surging segment in which precursor information of water inrush is contained before jumping appears, and rock seepage suddenly decreases after continuous decrease, but there exits an abnormal fluctuating segment in which precursor information of water inrush is contained long before water inrush happens, and rock apparent resistivity and acoustic