深厚覆盖层上土质心墙坝防渗墙-心墙接头局部无网格大变形分析  

Local large deformation between cut-off wall and core wall on deep overburden by meshless method

作　　者：邹德高[1,2] 龚瑾 孔宪京[1,2] 屈永倩 刘京茂[1,2] 陈楷 ZOU Degao;GONG Jin;KONG Xianjing;QU Yongqian;LIU Jingmao;CHEN Kai(State Key Laboratory of Coastal&Offshore Engineering,Dalian University of Technology,Dalian 116024,China;School of Hydraulic Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点试验室,辽宁大连116024 [2]大连理工大学建设工程学部水利工程学院,辽宁大连116024

出　　处：《岩土工程学报》2023年第9期1773-1781,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52192674,52109151)。

摘　　要：土质心墙坝作为覆盖层地基上的一种重要坝型,其上部土质心墙与下部混凝土防渗墙直接相连,由于材料刚度差异悬殊,两者在接头区域往往存在防渗墙“贯入”心墙的局部大变形现象。在任意拉格朗日-欧拉(ALE)框架下,开发了无网格大变形弹塑性分析方法,协同发挥了ALE框架在大变形分析中稳定和高精度的优势以及无网格法(Meshless)无需单元拓扑的特点,解决了有限元法因网格扭曲引发的精度降低或复杂重剖分问题。基于面向对象的C++语言,将该方法集成到自主开发的GEODYNA计算系统中,实现无网格大变形方法与有限元(FEM)、比例边界有限元(SBFEM)的无缝耦合。将耦合Meshless-FEM-SBFEM方法应用于某深厚覆盖层上土质心墙坝,联合土体广义弹塑性模型,再现了坝体在填筑过程中防渗墙“贯入”心墙的局部大变形发展过程,发现在竣工期小变形分析低估防渗墙竖向应力约4.1 MPa(占13%),并指出了防渗墙顶部两侧土体间存在剪切带。As a significant type of dam on deep overburden,the earth core rockfill dam connects the concrete cut-off wall and soil core wall directly,and the“penetration”phenomenon with local large deformation may exist between cut-off wall and core wall due to the difference in material stiffness.Using an arbitrary Lagrangian-Euler(ALE)framework,an elastic-plastic meshless large deformation method is developed in this research.The meshless method has the benefit of flexible nodal distribution,and the ALE framework shows the advantage of accuracy and stability in large deformation analysis,thus avoiding the precision reduction or re-meshing procedure in the mesh-based large deformation method.The introduced approach is incorporated into the self-developed calculation platform GEODYNA and combined with the finite element method(FEM)and the scale boundary finite element method(SBFEM).Finally,the coupled meshless-FEM-SBFEM applied to an earth core rockfill dam on deep overburden,and combined with the generalized elasto-plastic model,the“penetration”phenomenon with local large deformation is simulated.The results indicate that the large deformation analysis can capture the stress distribution of the cut-off wall and the soil deformation near the joint zone more reasonably,the vertical stress of the cut-off wall calculated by the small deformation analysis is underestimated by about 4.1 MPa(13%),and a shear zone exists between the soil area at the top of the cut-off wall.

关 键 词：大变形 无网格 任意拉格朗日-欧拉 深厚覆盖层 土质心墙坝 

分 类 号：TV641[水利工程—水利水电工程]