三轴循环载荷下砂岩的力学特性与能量演化规律  

Mechanical properties and energy evolution law behind sandstone under triaxial cyclic loading

作　　者：刘海涛[1] 杨心浩 Liu Haitao;Yang Xinhao(Key Laboratory of Mining Engineering of Heilongjiang Province College,Heilongjiang University of Science&Technology,Harbin 150022,China)

机构地区：[1]黑龙江科技大学黑龙江省普通高等学校采矿工程重点实验室,哈尔滨150022

出　　处：《黑龙江科技大学学报》2023年第1期18-23,39,共7页Journal of Heilongjiang University of Science And Technology

基　　金：黑龙江省揭榜挂帅科技攻关项目(2021ZXJ02A03)。

摘　　要：为探究粗砂岩在循环载荷条件下的力学特性和能量演化规律,开展了室内单轴压缩、常规三轴压缩和三轴分级循环加卸载试验,对比分析砂岩的力学特性。结果表明:循环加卸载试验下,砂岩试样峰值强度略低于常规三轴试验,与常规三轴相比循环载荷加大了裂纹的扩展,裂纹扩展发育情况复杂;三轴循环加卸载会提高砂岩试样的弹性模量,单次循环中卸载弹性模量总是高于加载弹性模量,循环载荷上限应力越大,塑性破坏越高;从能量角度可知,随循环应力上限的增大,滞回环面积越大,砂岩试样的总能量、弹性能和耗散能也随之增大,砂岩试样破坏前以弹性应变能储能为主。随着循环加载应力上限的增大损伤变量也相应增大,尤其在裂纹扩展阶段和破坏阶段。This paper intends to explore the mechanical properties and energy evolution law behind coarse sandstone under cyclic loading conditions. The study involves conducting loading and unloading tests including indoor uniaxial compression, conventional triaxial compression and triaxial graded cyclic to compare and analyze the mechanical properties of sandstone. The results show that the peak strength of sandstone samples under cyclic loading and unloading test is slightly lower than that of conventional triaxial test, and compared with the conventional triaxial test, cyclic loading makes the cracks larger and more complexed. Triaxial cyclic loading and unloading will increase the elastic modulus of sandstone samples, and the unloading elastic modulus is always higher than the loading elastic modulus in a single cycle. The greater the upper limit stress of cyclic load, the higher the plastic failure. From the energy point of view, with the increase of the upper limit of cyclic stress, the larger the hysteresis loop area, the higher total energy, elastic energy and dissipated energy of the sandstone sample also increase, and the sandstone sample is mainly stored by elastic strain energy before failure. With the increase of the upper limit of cyclic loading stress, the damage variable increases accordingly, especially in the crack propagation stage and failure stage.

关 键 词：砂岩 循环加卸载 力学特性 能量 损伤 

分 类 号：TD315[矿业工程—矿井建设]