摘要
为探究水-力耦合作用下岩石的流固耦合反馈特征,采用岩石力学多功能试验系统对饱水砂岩进行三轴及孔隙水压加载试验;共设置10、15、20 MPa 3组围压,每组围压下设置占比为0、20%、40%、60%的孔隙水压,分析了各级围压和孔隙水压对砂岩力学参数的影响程度;通过对比声发射响应特征分析了水-力加载下试件的损伤演化特性,获得了全应力应变过程中的渗透率变化曲线,并结合砂岩变形破坏特征进行了岩体裂隙-渗流耦合分析,得出了水-力耦合作用下岩石自破裂角发生剪切破坏的临界应力条件。试验结果表明:砂岩的峰值强度、弹性模量随着围压的增大而增大,且与孔隙水压呈负相关关系;砂岩的泊松比与孔隙水压呈正相关关系,围压越大,其线性关系服从性越强;砂岩峰值强度随围压、孔隙水压的变化规律遵循Mohr-Cou-lomb强度准则;在线弹性与伺服稳压阶段的交界处陆续发生较高能级的声发射事件,累计振铃计数和能量曲线呈现与应力同频率的阶梯状上升趋势;渗透率演化曲线表现为“先快速降低,再稳中带减,后快速上升,再急剧升降,后基本平稳”;高围压、低水压的渗透率最低,高围压试件渗透率随水压的增大呈正指数型增大,中低围压则呈负指数型增大;水-力耦合作用下岩石自身破裂角随水压的增大而增加。
In order to explore the fluid-solid coupling feedback characteristics of rock under the action of hydro-mechanical coupling,the triaxial and pore water pressure loading tests of saturated sandstone were carried out by using the rock mechanics multifunctional test system.Three groups of confining pressures of 10,15,20 MPa were set up,and the pore water pressures of 0,20%,40%and 60%were set up under each group of confining pressures.Then,the influence of confining pressure and pore water pressure on the mechanical parameters of sandstone is analyzed.The damage evolution characteristics of the specimen under hydro-mechanical loading were analyzed by comparing the acoustic emission response characteristics.The permeability variation curve in the whole stress-strain process is obtained,and the fracture-seepage coupling analysis of rock mass is carried out in combination with the deformation and failure characteristics of sandstone.The test results show that:the peak strength and elastic modulus of sandstone increase with the increase of confining pressure,and are negatively correlated with pore water pressure,and Poisson’s ratio is positively correlated with pore water pressure.The greater the confining pressure,the stronger the compliance of the linear relationship.The variation of the peak strength of sandstone with confining pressure and pore water pressure follows the Mohr-Coulomb strength criterion.The acoustic emission events with higher energy levels occurred at the junction of the on-line elasticity and servo voltage stabilization stages,and the cumulative ringing count and energy curve showed a stepwise upward trend with the same frequency as the stress.The permeability evolution curve shows that“the permeability decreases rapidly at first,then decreases steadily in the middle zone,then rises rapidly,then rises sharply,and then is basically stable”.The permeability of high confining pressure specimens increases exponentially with the increase of water pressure,while the permeability of medium and low confining pressure specimens increases exponentially with the increase of water pressure.The critical stress condition of shear failure of rock self-rupture angle under hydro-mechanical coupling is given,and the rupture angle increases with the increase of water pressure.
作者
李嘉伟
张玉军
肖杰
李友伟
张志巍
LI Jiawei;ZHANG Yujun;XIAO Jie;LI Youwei;ZHANG Zhiwei(Coal Mining Branch,China Coal Research Institute,Beijing 100013,China;China Coal Technology and Engineering Group Coal Mining Research Institute,Beijing 100013,China;Coal Mining and Designing Department,Tiandi Science and Technology Co.,Ltd.,Beijing 100013,China;State Key Laboratory of Intelligent Coal Mining and Strata Control,Beijing 100013,China)
出处
《煤矿安全》
北大核心
2025年第4期183-194,共12页
Safety in Coal Mines
基金
国家自然科学基金面上资助项目(52174079)
中国煤炭科工集团有限公司创新基金重点资助项目(2024-TD-ZD019)。
关键词
水-力耦合
孔隙水压
力学特性
声发射响应
渗透性-裂隙演化关系
hydro-mechanical coupling
pore water pressure
mechanical properties
acoustic emission response
permeability-fracture evolution relationship
