摘要
通过MTS815岩石力学试验系统对锦屏深埋大理岩开展常规三轴加载试验和不同初始围压、不同卸荷速率卸载试验,依托不同应力路径下深埋大理岩变形破坏过程中的能量演化特征进行渐进破坏阶段划分,并深入探究岩石渐进破坏过程中各特征应力对应的能量变化规律,以期为地下岩土工程设计及动力灾害预防提供参考。研究表明:不同应力路径下深埋大理岩能量演化曲线具有明显的阶段性,可分为弹性、塑性、屈服扩容、峰后4个渐进破坏阶段。大理岩渐进破坏过程中特征应力、特征能量均具有明显的围压效应,随围压增大特征应力线性增加,特征总能量、弹性应变能、耗散能均有所增加;较25,50 MPa,初始围压为80 MPa时,峰值弹性能最大,破坏时释放的能量更多,表现为中岩爆倾向;卸载条件下峰值应力更小,大理岩的承载能力降低,峰值总能量、弹性应变能、耗散能也减小。相同初始围压下,深埋大理岩的起裂应力、峰值应力与卸荷速率呈非线性关系,损伤应力随卸荷速率增大而线性增加;与加载相反,峰值总能量、耗散能随卸荷速率增大而减小;不同卸荷速率下大理岩均表现为无岩爆倾向,卸荷速率为1 MPa/s时,峰值耗散能最小,峰值弹性能最大,岩石损伤程度较小,破坏时释放的能量更多。
Through the MTS815 rock mechanics test system,conventional triaxial loading test and unloading tests with different initial confining pressures and different unloading rates were carried out on the deep-buried marble in Jinping.Based on the energy evolution characteristics of the marble deformation and failure process under different stress paths,the progressive failure stages are divided.The energy change law corresponding to each characteristic stress in the process of rock progressive failure is further explored.It can provide reference for underground geotechnical engineering design and dynamic disaster prevention.The research shows that energy evolution curve of deep-buried marble under different stress paths have obvious stages.It can be divided into four progressive failure stages:elasticity,plasticity,yield expansion and post-peak.During the progressive failure process of marble,the characteristic stress and characteristic energy have obvious confining pressure effects.With the increase of confining pressure,the characteristic stress increases linearly.At the same time,the total characteristic energy,elastic strain energy and dissipation energy are increased.Compared with 25 and 50 MPa,the peak elastic energy at 80 MPa is the largest.The energy released is more at failure.It is manifested as a tendency to explode in the middle rock.Under unloading conditions,the peak stress is smaller.The marble’s carrying capacity is reduced.The peak total energy,elastic strain energy,and dissipation energy also decrease.Under the same initial confining pressure,the crack initiation stress,peak stress and unloading rate of deep-buried marble show nonlinear relationship.The damage stress increases linearly with the increase of unloading rate.Contrary to loading,peak total energy,dissipated energy decreases with increasing unloading rate.Marble exhibit no rock explosion tendency at different unloading rates.When the unloading rate is 1 MPa/s,the peak dissipated energy is the smallest.In contrast,the peak elastic energy is the largest.The degree of rock damage is small,and more energy is released during failure.
作者
李泓颖
刘晓辉
郑钰
肖文根
LI Hongying;LIU Xiaohui;ZHENG Yu;XIAO Wengen(School of Energy and Power Engineering,Xihua University,Chengdu,Sichuan 610039,China;Key Laboratory of Fluid and Power Machinery,Ministry of Education,Xihua University,Chengdu,Sichuan 610039,China;Key Laboratory of Deep Earth Science and Engineering,Ministry of Education,Sichuan University,Chengdu,Sichuan 610065,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2022年第S02期3229-3239,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
西华大学重点科研基金(Z17113)
西华大学研究生创新基金(YCJJ2021056)
深地科学与工程教育部重点实验室(四川大学)开放基金(DESE202003)
关键词
岩石力学
能量演化
渐进破坏
特征应力
围压
卸荷速率
rock mechanics
energy evolution
progressive failure
characteristic stress
confining pressures
unloading rates
作者简介
李泓颖(1998-),女,2020年毕业于西华大学水利水电工程专业,现为硕士研究生,主要从事岩土工程方面的研究工作。E-mail:lihongying@stu.xhu.edu.cn;通讯作者:刘晓辉(1977-),女,博士,现任副教授。E-mail:liuxh@mail.xhu.edu.cn
