不同围压下深井煤岩短时蠕变试验的细观损伤机制分析
发布时间：2018-07-28 07:05
【摘要】：分析深井煤岩试验断口上矿物、结构、构造等的细观特征,追溯围压对其蠕变损伤机制的影响及调节作用,得到了围压分别为0、10和20 MPa的深井煤岩短时分级加载蠕变试验破坏断口的细观构造,分别对应解理断裂-节理裂隙、沿晶界断裂、沿晶界断裂-穿晶断裂。围压为0 MPa的单轴蠕变试验破坏断口,是煤岩受简单应力环境直接作用的结果,因此,其解理断裂和节理裂隙构造清晰、方向明确、内部新鲜且无夹杂。围压为10 MPa三轴蠕变破坏断口的沿晶界断裂间隙较宽、内部不干净、充填碎屑类夹杂,表明较强环向约束下的晶界较易于克服,且矿物结构以晶粒间的切向运动及力矩作用下的晶粒转动方式调整。围压为20 MPa的三轴蠕变试验,环向强约束使得晶界与晶粒的强度难以克服,最终破坏断口上的沿晶界断裂主要呈现弧形转动,穿晶断裂以剪切位移为主要特征,所以沿晶界断裂构造不太干净、内部充填围压先期作用时原生构造闭合后新产生的少量碎屑类夹杂,穿晶断裂间隙极小、新鲜、干净无夹杂。
[Abstract]:The microscopic characteristics of minerals, structures and structures on the test fracture surface of deep coal and rock are analyzed, and the influence of confining pressure on creep damage mechanism and its regulating action are analyzed. The microstructures of fracture surface destroyed by short-time graded loading creep test of coal and rock in deep wells with confining pressures of 0 ~ 10 and 20 MPa respectively are obtained, which correspond to cleavage fault-joint fracture and grain boundary fracture to transgranular fracture respectively. The failure fracture of uniaxial creep test with confining pressure of 0 MPa is the result of the direct action of coal and rock under simple stress environment. Therefore, the cleavage fracture and joint fracture have clear structure, clear direction, fresh interior and no inclusion. When the confining pressure is 10 MPa, the fracture gap along the grain boundary is wider, the interior is not clean, and the grain boundary is filled with clastic inclusions, which indicates that the grain boundary under strong circumferential constraint is easy to overcome. The mineral structure is adjusted by the tangential movement of the grains and the rotation of the grains under the action of torque. In the triaxial creep test with confining pressure of 20 MPa, the strength of grain boundary and grain is difficult to overcome due to the strong circumferential constraint, and the fracture along grain boundary at the end of the fracture presents an arc rotation, and the transgranular fracture is characterized by shear displacement. Therefore, the fault structure along grain boundary is not very clean, and a small amount of clastic inclusions are produced after the closure of the primary structure when the internal filling pressure is in advance. The transgranular fracture gap is very small, fresh and clean without inclusions.
【作者单位】： 山东农业大学水利土木工程学院;中国科学院武汉岩土力学研究所;
【基金】：山东省自然科学基金项目(No.ZR2014DM019) 国家自然科学基金项目(No.51574156,No.51004098)~~
【分类号】：TD315
本文编号：2149292
[Abstract]:The microscopic characteristics of minerals, structures and structures on the test fracture surface of deep coal and rock are analyzed, and the influence of confining pressure on creep damage mechanism and its regulating action are analyzed. The microstructures of fracture surface destroyed by short-time graded loading creep test of coal and rock in deep wells with confining pressures of 0 ~ 10 and 20 MPa respectively are obtained, which correspond to cleavage fault-joint fracture and grain boundary fracture to transgranular fracture respectively. The failure fracture of uniaxial creep test with confining pressure of 0 MPa is the result of the direct action of coal and rock under simple stress environment. Therefore, the cleavage fracture and joint fracture have clear structure, clear direction, fresh interior and no inclusion. When the confining pressure is 10 MPa, the fracture gap along the grain boundary is wider, the interior is not clean, and the grain boundary is filled with clastic inclusions, which indicates that the grain boundary under strong circumferential constraint is easy to overcome. The mineral structure is adjusted by the tangential movement of the grains and the rotation of the grains under the action of torque. In the triaxial creep test with confining pressure of 20 MPa, the strength of grain boundary and grain is difficult to overcome due to the strong circumferential constraint, and the fracture along grain boundary at the end of the fracture presents an arc rotation, and the transgranular fracture is characterized by shear displacement. Therefore, the fault structure along grain boundary is not very clean, and a small amount of clastic inclusions are produced after the closure of the primary structure when the internal filling pressure is in advance. The transgranular fracture gap is very small, fresh and clean without inclusions.
【作者单位】： 山东农业大学水利土木工程学院;中国科学院武汉岩土力学研究所;
【基金】：山东省自然科学基金项目(No.ZR2014DM019) 国家自然科学基金项目(No.51574156,No.51004098)~~
【分类号】：TD315
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