神东矿区煤系地层岩石物理力学性质

岩石物理力学参数是数值计算、相似模拟、顶板分类、支架选型等理论分析和现场安全生产管理的基础性工作。分别从补连塔煤矿、大柳塔煤矿及布尔台煤矿采集岩芯并进行了单轴压缩、三轴压缩和巴西劈裂实验,分析了不同沉积时期的密度、RQD值、抗拉强度、抗压强度、弹性模量、黏聚力及内摩擦角等参数。根据试验矿井地层情况,将3个试验矿井的岩层划分为8个沉积时期,分别为白垩系、侏罗系安定组、侏罗系直罗组、侏罗系延安组1-2煤、侏罗系延安组2-2煤、侏罗系延安组粉砂岩、侏罗系延安组4号煤及侏罗系延安组底部。神东矿区岩层以砂岩为主,尤其是白垩系岩层主要为砂岩层。按沉积时期分组试验结果表明:随着沉积时间的增加,岩石的密度呈增大趋势,但是增大幅度不明显;岩石的抗拉强度、抗压强度、弹性模量及黏聚力与沉积时间呈现出一定的正相关关系;RQD值及内摩擦角与生成时间无明显的关系。生成时间对岩石的力学参数影响较大,其中,沉积时间对中粒砂岩抗拉强度的影响最大,最大值是最小值的31.2倍;沉积时间对中粒砂岩抗压强度及弹性模量的影响最大,单轴抗压强度最大值是最小值的12.4倍;弹性模量最大值是最小值的32.8倍;白垩系及侏罗系安定组的物理力学参数相对其它沉积时期要小很多。

Physical and mechanical properties of the coal-bearing strata rock in Shendong coal field

The physical and mechanical parameters of rock are the basic data for numerical simulation,similar simulation,key layer judgment,roof classification,support selection.Therefore,the test drilling holes were drilled from the ground to the floor of coal seam in the coal mine of the Bulianta,Daliuta and Buertai.Brazil splitting,uniaxial compression and three axis compression tests were carried out.Finally,the parameters of density,RQD value,tensile strength,compressive strength,elastic modulus,cohesion and internal friction angle in different sedimentary periods were analyzed.The results indicate that the strata of three test mines can be divided into eight depositional periods,cretaceous and Jurassic diazepam group,Jurassic Zhiluo formation,Jurassic Yanan group 1-2 coal,Jurassic Yanan group 2-2 coal,Jurassic Yanan group siltstone,Jurassic Yanan group 4 coal and at the bottom of Jurassic Yanan group,respectively.The sandstone is the main rock in the strata of Shendong coal field,especially in Cretaceous,sandy mudstone and mudstone did not appear.With the increase of deposition time,the density of the rock has an increasing trend.However,the increase is not obvious.The tensile strength,compressive strength,elastic modulus and cohesion of the rock show a positive relationship with the deposition time.But there is no significant relationship among the RQD value,the internal friction angle and the deposition time.The deposition time has great influence on the mechanical parameters of the rock.The effect of deposition time on the tensile strength of mean-grained sandstone is the largest.The maximum value is 31.2 times of the minimum value.The effect of deposition time on the compressive strength and elastic modulus of mean-grained sandstone is the largest.The maximum value of compressive strength is 12.4 times of the minimum value.The maximum value of elastic modulus is 32.8 times of the minimum value.The physical and mechanical parameters of rock in the Cretaceous and Jurassic diazepam group are much smaller than other sedimentary periods.