含瓦斯煤孔隙率和有效应力影响因素试验研究

Experimental study of of influencing factor of porosity and effective stress of gas-filled coal

以孔隙率基本定义和力学平衡原理为出发点,充分考虑由煤层瓦斯的吸附膨胀和解吸收缩、温度效应的热胀冷缩和煤体骨架受孔隙瓦斯压力的压缩共同引起的本体变形,建立了在压缩条件下(扩容前)的含瓦斯煤孔隙率动态演化模型和以吸附热力学参数及瓦斯压力表达的有效应力方程,并分别根据现场实测孔隙率数据和含瓦斯煤三轴应力试验数据,对所建立的理论模型进行了验证。结果表明,理论计算值与实测资料和试验结论一致性较好,理论模型拟合精度较好,误差不大,所得结论对煤层气开采和矿井瓦斯灾害防治具有一定的指导意义。

According to the basic definition of porosity and mechanical equilibrium principle,and fully considering the primary deformation caused by the three aspects：the expansion of gas adsorption and shrinkage of desorption of coal seam,the expansion and shrinkage caused by the temperature effect,and the compression of the coal skeleton caused by the gas pressure of pore,a porosity dynamic evolution model of gas-filled coal under the compression condition（before expansion） and an effective stress equation expressed by adsorption thermodynamic parameters and gas pressure,are established According to the experimental data of porosity and triaxial stress test of gas-filled coal,the theoretical formula established above is verifed.The results show that the theoretical calculation results are consistent with the measured data and test conclusions.Fitting accuracy of theoretical model is good and the error is small.The research results have some guidance significance to the gas exploitation in coal seam and mining gas disaster prevention.