有限元强度折减法在底板突水风险评价中的应用  

Application of finite element strength reduction method to risk assessment of groundwater inrush from coal seam floor

作　　者：胡巍[1] 徐德金[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室资源与地球科学学院,江苏徐州221008

出　　处：《煤炭学报》2013年第1期27-32,共6页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(41172291);江苏高校优势学科建设工程资助项目;江苏省普通高校研究生科研创新计划资助项目(CX10B_146Z)

摘　　要：介绍了有限元强度折减法在FLAC3D中的实现方法。在分析煤层底板突水的有限元计算判断依据的基础上,阐明了底板安全系数Fs1的意义,即底板实际岩体强度与折减后底板破坏贯通时的岩体强度的比值定义为底板安全系数,它反映了承压水体上底板岩体抵抗破坏贯通的能力。通过有限元强度折减的实例计算验证了将该方法应用于煤层开采底板突水评价的可行性。计算结果表明:案例中工作面底板破坏的计算深度在15 m左右,与实测结果一致,底板安全系数Fs1为1.38;强度折减法揭示了底板突水的两条潜在的突水路径;底板安全系数Fs1随着工作面推进距离、工作面斜长及地应力的增大而减小。相较于突水系数,底板安全系数Fs1考虑因素更多,可信度更高。Introduced the finite element strength reduction method to the risk assessment for groundwater inrush from coal seam floor. On the basis of analyzing the groundwater inrush criterion of finite element calculation, the meaning of coal floor safety coefficient Fs1 was clarified. And the implementation approach of finite element strength reduction method in FLAC3D was introduced briefly. At last, the feasibility of this method using in groundwater inrush risk assess- ment was proved by a calculation of a case. The ratio of the actual rock mechanicals parameters to breaking mechani- cals parameters after strength reduction can be seen as the safety coefficient. The numerical results indicate that the depth of fractured floor is about 15 m in the example＇ s panel and the safety coefficient is 1.38. The safety coefficient reduces with the advance of the working face, the increase of the face length and in-situ stress. Two different water in- rush paths are demonstrated by the strength reduction method. Safety coefficient Fs1 is more credible because it consid- ers more factors than the traditional water bursting coefficient.

关 键 词：底板 突水 风险评价 有限元强度折减法 底板安全系数 

分 类 号：TD745[矿业工程—矿井通风与安全]