Study And Application Of Joint Mechanical Parameters Of Broken Compaction Rock Mass

The failure of crushing and compaction of rock mass is often caused by the cracking or sliding of the joint surface between rock blocks.The rock block itself does not break down.The mechanical parameters of the joint face between rocks are studied to ensure the safety of coal under crushing and compaction rock mass.Mining is of great significance.In this paper,laboratory tests,theoretical analysis and numerical simulation are used to determine and study the mechanical parameters of the overall joint surface of the crushing and compaction rock mass.The main results are as follows:(1)Compressed solid bodies with different particle size ranges and different compression ratios were prepared.The uniaxial compression test was performed on the compacted body to obtain the stress-strain curve of the compacted body.Tests showed that the smaller the particle size and the higher the compression ratio,the compacted body The higher the compressive strength,the reverse is also true;the statistical probability and the mathematical method were used to determine the probability distribution of the compressive body node trace length as a negative exponential distribution.The number of compression joints in each particle size range was calculated and the random joint was determined.The basic joint geometry parameters required for the network.(2)The mechanical parameters of the joints of nine compressional solids were designed by orthogonal test method.According to the joint geometric parameters determined by the test,a random joint network was generated based on the Monte Carlo principle,and then the 3DEC numerical model of the compacted body was generated.The uniaxial compression of the compacted body was numerically simulated,and nine kinds of mechanical parameters of the joint were substituted to obtain the uniaxial compressive stress-strain curve.Compared with the results of the indoor test,the intrinsic stiffness,tangential stiffness,and stickiness of the joint face of the four compressive solids were obtained.Mechanical parameters such as cohesion force and internal friction,etc.;Sensitivity study of the mechanical parameters of the compression solid joint surface were determined,and the influence degree of each parameter on compressive strength and elastic modulus of the compression body was determined.(3)According to the mechanical parameters of the four compressive solid joints obtained,a 3DEC numerical model of crushing and compaction rock mass was established.The settlement of the roof of the roadway,the distribution characteristics of normal stress on the joint and the effect of bolt support were analyzed.The results show that the top of the middle joint surface of roadway roof is squeezed and the bottom has cracking tendency;the bottom of the joint surface is under pressure,the top has cracking tendency,the top plate of the roadway middle layer appears the phenomenon of stratification,and the bolting effect of the roadway in the roadway is significant.The settlement of the roof plate decreased significantly,and the collapse of the irregular roof plate disappeared.