韩城地区煤岩力学特性与破坏特征试验

Experimental investigation on mechanics properties and failure of coal in Hancheng

韩城地区二叠系下统的山西组煤岩为含裂隙的低强度高脆性介质,其抗压强度和破坏特性与加载方式和加载速率有密切的关系。利用室内试验方法,对该地区煤层气储层煤岩开展了不同加载方式的力学研究。试验结果表明,煤岩的主裂隙(面割理)走向与加载方向的关系对煤岩的力学特性有较大影响,煤岩裂隙走向与加载方向垂直时的抗压强度是裂隙走向与加载方向平行时抗压强度的1.35倍;而弹性模量和泊松比正好相反,煤岩裂隙走向与加载方向平行时的弹性模量是裂隙走向与加载方向垂直时弹性模量的1.66倍,泊松比为1.15倍;在同等试验条件下,随着加载速率的增大,煤岩强度提高,但脆性增大,易呈脆性破坏。研究成果可为裂隙型煤岩的力学特性认识及在工程中的应用提供参考。

The coal in Shanxi Formation of Lower Permian System in Hancheng is a fissured medium of high brittleness and low strength,and its compression strength and failure have a close relationship with the loading conditions and the loading rates.The paper,using rock mechanics method,carried out the res earch on the m echanical tests through different experimental method for coalbed methane engineering in Hancheng.The experime ntal results demonstrate that the relat ion of the loading directi on with the direction of the m ain fracture（cleat） has an important effect on the mechanical properties.When the fracture strike is vertical to loading direction,the compression strength of coal rock is 1.35 times higher than that when the fracture strike is parallel to loading direction.The magnitudes of the elastic modulus and the Poison’s ratio,however,are just opposite.When the fracture strike is parallel to l oading direction,the elastic modulus of co al rock is 1.66 times higher than t hat when the fracture strike is vertical to loading direction,and Poison’s ratio is about 1.15 times;Under the same experimental conditions,the coal will be more brittle and its strength increases with the loading rate.Thus,the research results may provide some references for recognizing the mechanical properties of fissured coal rock and its applications in engineering.