重力坝纵缝非连续接触的数值模拟
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摘要
本文在六参数(法向刚度、切向刚度、粘聚力、摩擦角、剪胀角和抗拉强度)界面单元的基础上,利用给定初始应力模拟裂隙初始宽度,采用变参数法模拟裂隙闭合与张开状态下的力学行为,从而使改进后的界面单元可以模拟非连续接触问题。利用改进后的界面单元,研究了重力坝纵缝张开宽度及其分布形式、坝体并缝措施和缝面键槽对坝体变形和应力的影响。研究表明,纵缝张开宽度及其分布形式对坝体变形和应力影响显著,并缝措施会引起并缝部位应力集中,键槽可以阻止接缝面产生相对滑移。
On the basis of interface element with 6 parameters including the normal stiffness, shear stiffness, cohesion, friction angle, dilatancy angle and tensile strength an improved interface element is suggested. The initial width of the joint opening can be simulated according to the given initial stress. The variable parameters method is used to simulate the mechanical behaviors of the opening. The improved interface element method is adopted to study the effects of width and distribution of longitudinal joints, amalgamation of joints, key grooves on deformation and stress in gravity dam with opened vertical construction joints. The study result shows that the width and distribution of joints have significant effect on the deformation and stress in gravity dam. The measure of amalgamation of joint will induce stress concentration and key grooves will restrain the sliding along the joints.
On the basis of interface element with 6 parameters including the normal stiffness, shear stiffness, cohesion, friction angle, dilatancy angle and tensile strength an improved interface element is suggested. The initial width of the joint opening can be simulated according to the given initial stress. The variable parameters method is used to simulate the mechanical behaviors of the opening. The improved interface element method is adopted to study the effects of width and distribution of longitudinal joints, amalgamation of joints, key grooves on deformation and stress in gravity dam with opened vertical construction joints. The study result shows that the width and distribution of joints have significant effect on the deformation and stress in gravity dam. The measure of amalgamation of joint will induce stress concentration and key grooves will restrain the sliding along the joints.
引文
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[3]Goodman R E,Taylor RL,Brekke TL.Amodel forthe mechanics of jointedrock[J].Journal of the Soil Mechanics and Foundation,1968,194(3):637-659.
[4]Desai C S,Zaman M M,et al.Thin-layer element for interfaces and joints[J].International Journal for Numerical Methods in Geomechanics,1984,8:19-43.
[5]Cundall P A.Distinct element models of rockandsoil structure[A].Analytical and Computational Methodsin Engineering Rock Mechanics[C].London,Allen&Unwin,1987.129-163.
[6]石根华.数值流行方法与非连续变形分析研究[M].北京:清华大学出版社,1997.
[7]栾茂田,黎勇,林皋.非连续变形计算力学模型及其在有缝重力坝静力分析中的应用[J].水利学报,2001,(4):40-46.
[8]Itasca Consulting Group Inc.Online Manual for Fast Lagrangian Analysis of Continua in3Dimensions,Version2·1[M].Minneapolis,Minnesota,USA,Itasca Consulting Group Inc.,2002.
[9]孙广忠.岩体结构力学[M].北京:科学出版社,1988.211-212.
[10]吴媚玲.水工建筑物[M].北京:清华大学出版社,1991.48-49.
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