加卸载条件下煤样能量与渗透特性试验研究

Experimental study on energy and permeability characteristics of coal samples under loading and unloading conditions

为了研究煤样在开采影响下的动态演化过程,基于含瓦斯煤热流固耦合三轴伺服渗流装置,进行了常规三轴加载试验和加卸载试验,分析煤样的能量演化规律和渗透特性。研究结果表明,加卸载试验较加载试验下试样的扩容起始点发生提前。加卸载试验中总能量比加载试验中的总能量要大,耗散能演化更加剧烈,而弹性能可以更早达到储能极限;在加卸载试验中耗散能超越弹性能占比的特征点发生提前。渗透率均表现出先快速下降后缓慢下降的规律。该研究对煤与瓦斯共采具有重要指导意义。

In order to study the dynamic evolution process of coal samples under the influence of actual mining,based on triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing methane,conventional triaxial loading test and loading-unloading test were conducted to analyze the energy evolution law and permeability characteristics of coal samples.The results of the study showed that the onset of dilation of the specimens in the volumetric strain occurred earlier in the loading and unloading tests than in the loading test.The total energy in the loading-unloading test is larger than that in the loading test,and the dissipative energy evolves more drastically,while the elastic energy can reach the storage limit earlier;the characteristic point where the dissipative energy exceeds the elastic energy share in the loading-unloading test occurs earlier.The permeability of different tests all show a pattern of rapid decrease first and then slow decrease.The above study has important guiding significance for coal and gas co-mining.