煤岩体水射流破碎机理

假设非均质岩体微元的弹性模量和抗压强度均服从Weibull分布，用愈渗理论推导了非均质岩体的水射流破坏准则和水射流破碎非均质岩体的门槛压力；数值模拟了水射流在非均质煤层中的连续钻孔过程；并进行了水射流的破煤实验.研究表明，在水射流作用下，煤岩体中强度较弱的一系列微元首先破坏，形成裂隙.进入裂隙空间的水射流对裂隙发生的水楔作用，使裂隙尖端产生拉应力集中，导致裂隙迅速发展和扩大，裂隙与裂隙连通后使得大块的煤岩体脱落，形成破碎坑.当水射流压力为60 MPa时，煤体破碎距离达到0.5 m以上.

Mechanical of breaking coal by water jet

Supposed that the elastic modulus and compressive strength of inhomogeneity rock mess cells conform to Weibull distribution.Deduced breaking rule of inhomogeneity rock mess by water jet and the threshold pressure of water jet with percolation theory,numerical simulated continuous drilling in the inhomogeneity coal by water jet with finite elements method and the experiment of breaking coal by water jet was carried out.The study indicates that under water jet,the low strength cells in inhomogeneity rock mess are first destroyed,a crack is created under water jet,the effect of the water wedge occurring by water jet which enters the crack space producing tensile stress concentration at the tip of a crack,so the cracks expand rapidly and converge gradually,eventually the rocks mess are fragmented,a cracked pit is formed.The cracked distance of coal by water jet at 60 MPa is more than 0.5 m.