摘要
高孔隙率砂岩是油气藏、地下水等的重要储层,对其在不同加载条件下破坏模式演化的研究具有重要意义。采用有限元与离散元耦合的分层多尺度模拟方法,对同一种高孔隙率砂岩材料在(排水)双轴压缩试验、钻孔稳定性问题、水岩耦合问题等典型岩土工程边值问题中,破坏模式的演化进行了对比研究。研究表明,高孔隙率砂岩在不同加载条件下可以产生压缩带、含剪切变形带等具有显著不同几何特征的破坏模式;受应力集中、边界条件、孔隙压力变化等因素的影响,不同破坏模式之间可能发生演化,在边值问题中产生复杂的破坏形式;有效平均应力增加可能导致破坏模式从含剪切变形带演化为压缩带,反之,有效平均应力降低也可能导致从压缩带向剪切带的演化。
High-porosity sandstones are important host rocks for hydrocarbon and groundwater reservoirs.It is of significance to investigate their failure pattern transitions under different loading conditions.A hierarchical multiscale modeling approach is employed,coupling the finite element method and the discrete element method,to compare and analyze the failure pattern transition in typical geotechnical boundary value problems,e.g.,(drained)biaxial compression tests,borehole stability problems,hydro-mechanical problems,etc.The failure patterns with distinct geometric features,including pure compaction band and shear-involved deformation band,are formed under different loading conditions.The transitions between different patterns,due to stress concentration,boundary conditions,pore pressure,etc.,complicate the failure patterns in boundary value problems.The increase in the effective mean stress tends to transit the shear-involved band deformation to the compaction band one and the decrease tends to cause the transition from the compaction band deformation to the shear-involved band one.
作者
吴焕然
刘汉龙
赵吉东
肖杨
WU Huan-ran;LIU Han-long;ZHAO Ji-dong;XIAO Yang(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China;Department of Civil and Environmental Engineering,Hong Kong University of Science and Technology,Hong Kong,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第12期2222-2229,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51922024,51679207)
香港研究资助局项目(GRF 16210017)。
关键词
高孔隙率
砂岩
压缩带
剪切带
模式演化
平均应力
多尺度
high porosity
sandstone
compaction band
shear band
pattern transition
mean stress
multiscale
