基于水压致裂法的岩石抗拉强度研究  

Research on tensile strength of rock based on hydraulic fracturing method

作　　者：刘跃东[1,2,3] 林健[1,2,3] 冯彦军[1] 司林坡[1] LIU Yue-dong;LIN Jian;FENG Yan-jun;SI Lin-po(Coal Mining and Design Branch, China Coal Research Institute, Beijing 100013, China;Coal Mining and Design Department, Tiandi Science ＆ Technology Co., Ltd., Beijing 100013, China;State Key Laboratory of Coal Mining and Clean Utilization, China Coal Research Institute, Beijing 100013, China)

机构地区：[1]煤炭科学研究总院开采设计研究分院,北京100013 [2]天地科技股份有限公司开采设计事业部,北京100013 [3]煤炭科学研究总院煤炭资源高效开采与洁净利用国家重点实验室,北京100013

出　　处：《岩土力学》2018年第5期1781-1788,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金煤炭联合基金重点支持项目(No.U1261211);中国煤炭科工集团重点项目(No.2014ZD001)~~

摘　　要：为了揭示水压致裂法和巴西劈裂法测量岩石抗拉强度的关系,开展了理论和现场试验研究。基于经典的水压致裂法理论,推导了不同围压下钻孔破裂压力和抗拉强度。利用断裂力学理论建立了水压致裂法和巴西劈裂法测得抗拉强度的关系。利用预制切槽方法模拟天然裂纹,对水力裂缝的起裂压力进行了研究。结果表明:围压为最大主应力等于3倍最小主应力测得的抗拉强度大于围压为0测得的抗拉强度;水压致裂法和巴西劈裂法测量抗拉强度关系与应力场、裂纹长度、断裂韧度3个变量有关;通过在晋城矿区王台铺矿的预制切槽试验,运用断裂力学建立的抗拉强度计算式更为符合现场实际。研究结果可为坚硬难垮落顶板预制切槽的水力压裂设计提供参考。Theoretical and field experiments were carried out to reveal the relationship between the hydraulic fracturing method and the Brazilian splitting method for measuring the tensile strength of rock. Based on the classical hydraulic fracturing theory, borehole rupture pressure and tensile strength of rock were deduced under different confining pressures. The fracture mechanics theory was applied to establish the relationship between these two methods. Meanwhile, the crack initiation pressure of the hydraulic fracture was studied by using the prefabricated crack method to simulate natural crack. The results show that when the maximum principal stress was three times the minimum principal stress, its measured tensile strength was higher than that without confining pressure. The relationship between these two methods was related to three variables, including stress field, crack length and fracture toughness. The prefabricated crack experiment was performed at Wangtaipu Mine in Jincheng mine area. It was proved that the tensile strength formula established by fracture mechanics was more suitable for practical applications. The research results can provide references for the hydraulic fracturing design of prefabricated cracks in the hard and stable roof.

关 键 词：水压致裂 抗拉强度 断裂力学 预制切槽 

分 类 号：TU452[建筑科学—岩土工程]