摘要
核废料储存、地热开发等岩体施工过程中经常遇到液-力耦合(H-M)问题,给安全施工带来了巨大挑战。开展液-力耦合相关模拟问题的研究对岩体工程领域发展具有一定的现实指导意义与参考价值。FRACOD软件中的H-M耦合采用位移不连续法计算裂隙的变形和张度、用立方定律等方法依次对相邻裂隙单元之间流量、水压进行计算,再通过力学部分及液体流动部分的动态时步迭代循环,进而获得最终岩体破裂状态。为进一步验证FRACOD中液-力耦合模块的模拟效果,以地热开发中水力压裂及节理岩体中裂纹传播过程为例进行分析。模拟结果表明,在高应力环境中,天然裂隙岩体在水压及原岩应力共同作用下发生了明显的剪切滑移,受裂纹剪切的影响天然裂隙的水力孔径增加了80%,裂隙内部流体流动明显增强;在液-力耦合作用下,液体驱动的裂纹与岩石节理贯通且贯通后的节理继续向最大主应力方向扩展,模型结果直观地展现了耦合裂纹的起裂、扩展和贯通全过程以及应力场、声发射等物理场信息的分布规律。FRACOD中液-力耦合模块的开发,可成为研究岩体液-力耦合问题的工具,进而为岩体工程领域提供一种新的模拟方法和手段。
The hydro-mechanical coupling(H-M)problems frequently encountered in the process of rock mass construction,such as nuclear waste storage and geothermal development,bring great challenges to the engineering safety.It is of practical significance for the development of rock mass engineering to study the H-M coupling related problems.Displacement discontinuity method was adopted in H-M coupling in FRACOD to calculate the fracture deformation and aperture changes,and the cubic law was used to calculate the flow and water pressure of adjacent fracture units.The ultimate fracture state of rock mass was obtained by dynamic time-marching explicit iteration of the mechanical and fluid flow processes.In order to further verify the simulation effect of the hydro-mechanical coupling function in FRACOD,the hydraulic fracturing and crack propagation in jointed rock mass in geothermal development were analyzed as an example.The simulation results show that in a high-stress environment,naturally fractured rock mass undergoes significant shear slip under the combined action of water pressure and original rock stress;the hydraulic aperture of natural fractures is increased by 80%due to crack shearing;and the hydraulic conductivity inside the fracture is thus significantly enhanced.Under the condition of hydro-mechanical coupling,the hydraulically driven cracks coalesce with the pre-existing rock joints,which continue to propagate in the direction of the maximum principal stress.The result of the model shows directly the whole process of crack initiation,propagation and coalescence as well as the distribution of physical field information such as stress field and acoustic emission.Therefore,the hydro-mechanical coupling function in FRACOD can be used as a tool for studying hydro-mechanical coupling problems in rock masses and provides a new simulation method and means for rock mass engineering.
作者
沈宝堂
柴顺杰
张士川
陈兵
SHEN Baotang;CHAI Shunjie;ZHANG Shichuan;CHEN Bing(State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, Shandong 266590, China;CSIRO Mineral Resources, Queensland Centre for Advanced Technologies, Brisbane, Queensland 4069, Australia)
出处
《山东科技大学学报（自然科学版）》
CAS
北大核心
2021年第3期26-34,共9页
Journal of Shandong University of Science and Technology(Natural Science)
基金
国家自然科学基金项目(51974173,52004147)
山东省重点研发计划项目(2019GSF111024)
山东省自然科学基金项目(ZR2020QE129)。
关键词
FRACOD
位移不连续法
液-力耦合
水力压裂
裂纹扩展
FRACOD
displacement discontinuity method
hydro-mechanical coupling
hydraulic fracturing
crack propagation
