岩土工程连续极限分析方法拓展与验证  

Extension and validation of sequential limit analysis for geotechnical problems

作　　者：王祖乐 孔德琼[1,2] 杜越明 朱斌 WANG Zu-le;KONG De-qiong;DU Yue-ming;ZHU Bin(Center for Hypergravity Experimental and Interdisciplinary Research,Zhejiang University,Hangzhou,Zhejiang 310058,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou,Zhejiang 310058,China)

机构地区：[1]浙江大学超重力研究中心,浙江杭州310058 [2]浙江大学建筑工程学院,浙江杭州310058

出　　处：《岩土力学》2023年第12期3531-3540,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52071289,No.51988101)。

摘　　要：连续极限分析(sequential limit analysis,SLA)方法在近年来被引入岩土工程领域,该方法将大变形岩土工程问题分解为一系列小变形有限元极限分析问题进行求解,已成功应用于平面应变条件下管道等结构物与不排水软黏土大变形相互作用的分析。SLA法具有较高的计算效率与数值稳定性,且计算误差可基于上限解与下限解偏差进行实时评估。将现有平面应变SLA法进行拓展,以适用于球形触探仪、管桩基础、桩靴基础竖向贯入等旋转轴对称问题,并且基于通用数值平台OPTUM进行开发,使该方法更具一般性。同时,改进了原SLA法中对极限上限解所得机动场的更新方法,使其能够适应更为极端的土体变形。通过与一系列经典塑性解案例和模型试验的对比,验证了拓展后SLA法的准确性和有效性。该方法可实现不排水条件下基础、触探装备和管道等设施与软黏土竖向与水平向极端大变形相互作用的高效模拟。Sequential limit analysis(SLA)has been recently introduced into geotechnical engineering,in which a large-deformation problem is discretized into a sequence of small-deformation finite element limit analyses,and has been successfully used for the analysis of soil-structure interactions in undrained soft clay under plane strain condition.SLA method possesses high computational efficiency and numerical stability,and its calculation error can be real-time evaluated based on the deviation between upper-bound and lower-bound solutions.In this paper,the existing plane strain SLA method is extended to be suitable for axisymmetric problems such as vertical loading behavior of spherical probe instruments,pipe piles and spudcans.A new version of SLA is developed on the numerical platform OPTUM to broaden its usage.Additionally,the updating method of the model geometry based on velocity fields obtained from upper-bound solution in the original SLA is improved,so that it can adapt to more extreme soil deformation.A series of classical plastic solution cases and model tests are then used to validate the accuracy and effectiveness of the extended SLA method.It proves that this method can be used to simulate large displacement/deformation problems such as the vertical and lateral interactions between undrained clay and facilities such as foundation,penetration equipment and pipelines.

关 键 词：大变形分析 极限分析 软黏土 海洋岩土工程 

分 类 号：TU454[建筑科学—岩土工程]