开洞刚性墙后土体破坏模式运动单元上限分析  

Failure mechanism analysis of soil behind a perforated rigid wall by the upper bound method with rigid translatory moving element

作　　者：盛兴旺[1] 孙焕重 秦傲韩 杨鹰[1] 杨峰[1] 郑纬奇 SHENG Xingwang;SUN Huanzhong;QIN Aohan;YANG Ying;YANG Feng;ZHENG Weiqi(School of Civil Engineering,Central South University,Changsha 410075,China;China Railway 14th Bureau Second Engineering Co.,Ltd.,Tai’an 271000,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中铁十四局集团第二工程有限公司,山东泰安271000

出　　处：《铁道科学与工程学报》2024年第7期2827-2838,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52078488)。

摘　　要：超载作用下开洞地下刚性连续墙后土体稳定性问题具有广泛的工程应用背景。考虑墙体矩形开洞宽度足够大,且刚性墙与土体完全光滑接触等条件,参考构造刚性多块体上限法思路,预设墙后土体极简破坏机构并转化为初始三角网格,提出交替循环式新增节点、单元缩减、对角互换及成层加密等网格更新措施,同步开展基于刚体平动运动单元上限方法的刚性墙后土体破坏分析,通过多层级非线性规划运算获得高精度临界超载系数σ_(s)/c上限解,界定墙后土体滑移线网破坏模式及其定量范围与扩展边界。进一步依前述流程计算获得多参数影响下的临界超载系数σ_(s)/c上限解图表,结果表明:1)刚性墙后土体典型破坏特征表现为土体上方和开洞处的整体下沉刚性区域,开洞前方核心区域以密集滑移线网区隔的刚性滑块群,以及外围主要滑动面;2)临界超载系数σ_(s)/c随土体内摩擦角ϕ增大而增大,且后续增幅显著增加;3)σ_(s)/c随开洞深度比C/D的增大呈现出近似线性增大的趋势;4)相较于ϕ和C/D,土体重度参数γD/c的变化对于σ_(s)/c的影响不甚明显,σ_(s)/c随γD/c增大呈现近似线性减小的趋势;5)σ_(s)/c受剪胀角参数ψ/ϕ的影响与ϕ的增大程度密切相关。本研究结果可为开洞地下刚性连续墙后土体失稳破坏模式定量分析、破坏机理研究及工程措施制定等工作提供有力的数据支持。The stability issue of soil behind the underground rigid continuous wall with openings under overload has broad applications.Considering the width of rectangular opening on the wall is large enough,and the interface between rigid wall and soil is completely smooth,refer to the idea of the rigid block upper bound method to assume simplified failure mechanism of retained soil behind rigid diaphragm wall transformed into an initial triangular mesh.An iterative cyclic approach that involves mesh update such as nodes addition,elements reduction,diagonal swapping,and layered element refinement was proposed.Stability analysis of retained soils behind underground walls with an opening was studied by using upper bound method with rigid translatory moving element.Based on multi-level nonlinear programming,more accurate upper bound solutions for the critical loading factor coefficientσ_(s)/c were obtained.Based on these solutions,slip-line failure mechanisms behind rigid diaphragm wall and quantitative ranges and expanded boundaries were defined.In subsequent computation,the upper bound solutions for the critical overloading coefficientσ_(s)/c in form of charts was generated for various parameters.The results are drawn as follow.1)Typical failure mechanism characteristics behind the rigid wall are characterized by overall subsidence area above soil above and at the opening.The failure area is mainly in rigid block groups of densely slip-line area in the core region in front of the opening,and primary sliding surfaces on the periphery.The critical overloading factorσ_(s)/c increases with an increase in the internal friction angleϕof the soil,with a considerable increase in subsequent procedure.σ_(s)/c exhibits an approximate linear increase with an increase in the ratio of opening depth to width(C/D).Compared toϕand C/D,the variation in soil density parameterγD/c has mild impact onσ_(s)/c.With an increase inγD/c,σ_(s)/c increases.It shows an approximate linear decrease.The influence of the shear dilation angle para

关 键 词：地下刚性墙 临界超载 上限分析 网格更新 破坏模式 滑移线网 

分 类 号：TU443[建筑科学—岩土工程]