考虑瓦斯压力的煤体三轴抗压强度研究

摘要

从煤体强度的角度来分析含瓦斯煤岩的破坏行为，通过实验分析了考虑瓦斯压力的含瓦斯煤岩的抗压强度。研究表明：在三向应力状态下，煤样的破坏形态受侧压的影响；煤样的残余变形与试验的侧压及本身的强度有关，煤样的强度越大，残余变形就越小；在试验侧压的范围内，煤样的弹性模量随侧压的增大而增大。与单轴压缩相比，含瓦斯煤的抗压强度和弹性模量都有所降低。原因在于：煤样制备的时候较为松散及瓦斯压力的影响。煤的强度受其中瓦斯气体的影响较大，煤体吸附瓦斯后体积膨胀强度降低，而煤体释放瓦斯后强度增加。%The destruction behavior of gassy coal - rock is analyzed from the perspective of coal mass strength, compressive strength of gassy coal - rock considered gas pressure is analyzed by the experiments. The research result shows that lateral pressure effects on fail- ure mode of gassy coal in three - dimensional stress state; residual deformation of gassy coal is related to experimental lateral pressure and coal strength ; the greater of the gassy coal strength is, the smaller of the residual deformation is ; the elastic modulus of coal increa- ses with the increasing of lateral pressure within the experimental lateral pressure. Both of the compressive strength and elastic modulus decrease compared with uniaxial compression because of the loose gassy coal in the stage of preparation and the effect of gas pressure. The gas has a great effect on strength of coal. Coal strength decreases when it adsorbs gas, and it enhances when gas is released from coal.