煤层顶板破碎岩石压实特征的试验研究

EXPERIMENT STUDY OF COMPACTION CHARACTERISTICS OF CRUSHED STONES FROM COAL SEAM ROOF

为研究煤层顶板破碎岩石压实特征,对义马新安煤层顶板砂岩、砂质泥岩和泥岩,利用自制装置在RMT-150B电液伺服岩石力学试验系统上进行压实试验,得到3种碎石压实试验的应力-应变关系,分析岩石强度、块径、压实应力对碎石压实特性的影响。结果表明:碎石压实变形过程可分为快速压实、缓慢压实和稳定压固3个阶段;碎胀系数随块径增大而增加,可以采用对数关系描述;碎石经历压实后残余碎胀系数与岩石强度、块径的关系不大,差异性有所减小,碎胀系数减幅与块径相关,块径越大减幅越大;压实度为压实应力的函数,块径越大压实度变化越明显;压实能耗随岩石强度增高而増大,砂岩、砂质泥岩与泥岩平均能耗比约为3.5∶2.2∶1.0,同种岩石块径大于5 mm后压实能耗与块径关系不大。

To study compaction characteristics of crushed stones, the compaction tests on sandstone, mudstone and sandy mudstone from coal seam roof of Yima Xin＇an mine were conducted by using RMT - 150B servo machine. Stress-strain relation of crushed stones is obtained and the effects of rock strength, particle size and compaction stress on compression characteristics are analyzed. The results show that three stages are included by the following order during compaction process： rapid compression deformation stage, slow compaction deformation stage and stable compaction stage. The bulking factor increased with the increase of particle size by the logarithmic relationship. The difference of residual bulking factor after crushed stones experienced close and filling of interstice decreased, which has less to do with rock strength and particle size. The decrease amplitude of bulking factor augmented with the increase of lumpiness. The compactness of crushed stones is a function of compaction stress and the bigger the lumpiness was, the more obvious the change of compactness was. The higher the rock strength is, the greater the energy consumption is; and the average energy consumption ratio of sandstone, sandy mudstone and mudstone is 3.5 ; 2.2 ： 1.0. If the particle size of same stone is larger than 5 mm, the energy consumption is not relevant to the particle size.