煤矿冲击矿压动静载叠加原理及其防治

Rock burst prevention methods based on theory of dynamic and static combined load induced in coal mine

煤矿冲击矿压动力灾害日趋严重,且浅部也出现了该现象。理论研究了动载与静载叠加诱发冲击矿压的能量和应力条件,系统地提出了动静载叠加诱发冲击矿压的原理,并分析了煤矿动静载特征,根据应变率对煤矿载荷状态进行了界定,试验研究了煤岩力学特性与应变率的关系以及动静叠加作用下煤的破坏形态。结果表明:随着应变率增大,煤岩强度、弹性模量呈指数关系增大,当静载占比较大时,煤岩呈剪切破坏;当动载占比较大时,煤岩呈现劈裂甚至爆裂破坏。当动静叠加接近煤岩强度时,单轮或多轮动载作用可诱发煤岩冲击破坏;当动静叠加远小于煤岩强度时,多轮动载虽然能使煤岩产生损伤但难以诱发冲击破坏。动静叠加诱发冲击矿压表现为2种类型:1高静载型,深部开采时,围岩静载较高,矿震产生的微小动载增量可使叠加载荷超过煤岩冲击破坏临界而诱发煤岩冲击破坏;2强动载型,浅部开采时,围岩静载较小,强矿震的冲击动载较大,叠加载荷超过煤岩冲击破坏临界导致煤岩冲击破坏。基于冲击矿压的动静载叠加诱发原理,讨论了冲击矿压监测及防治思路和方法。

Rock burst is becoming more and more serious in coal mine,and the scene of action of which is becoming much shallower. Theoretically studied rock burst energy and stress conditions under dynamic and static combined load,and the theory of dynamic and static combined load inducing rock burst was systematically put forward,and the dynamic and static load characteristics of coal mine were analyzed. According to the loading strain rate,the loading state was defined of coal mine. The experimental research on the mechanical characteristics of coal and rock samples under different strain rate and destruction shape of coal and rock under dynamic and static combined load was carried out.The results show that,with strain rate increasing,the coal and rock strength and elastic modulus exponentially increa-ses,and when the static load is predominant,coal rock shows shear failure,and when the dynamic load is predominant,the coal rock shows splitting or even bursting damage,and when the combined load closes to coal strength,during the single or multi wheel dynamic loading the coal can be induced dynamic failure,and when the combined load is far less than the coal strength,multi wheel dynamic loading can make the coal damage but cannot induce it to dynamic failure. Combined dynamic and static load induced rock burst can be divided into two types. The first is high static loading type. When it is deep mining,the static load is very high originally,although the load has not yet reached the critical value of rock burst,the micro dynamic load increment generated by mine micro seismicity can make the combined load exceeds the critical value and resulting in rock burst; The second is strong dynamic loading type. When it is shallow mining,although the static load is small,the strong mining earthquake caused fierce dynamic load,and the combined load exceeds the rock burst critical value,the rock burst can be induced. Finally,based on the dynamic and static combined load inducing rock burst principle,the ideas and methods of monitoring and prevention of rock burst was proposed.