土质边坡数值模型稳定性的求解精度研究  

Study on Solution Accuracy of Numerical Model Stability with Soil Slope

作　　者：武博强 王勇 张葆永 程振全 杨德宏 WU Bo-qiang;WANG Yong;ZHANG Bao-yong;CHENG Zhen-quan;YANG De-hong(CCCC First Highway Consultants Co.,Ltd.,Xi’an Shaanxi 710065;China Railway First Survey and Design Institute Group Co.,Ltd.,Xi’an Shaanxi 710043)

机构地区：[1]中交第一公路勘察设计研究院有限公司,陕西西安710065 [2]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《公路交通科技》2024年第1期71-78,共8页Journal of Highway and Transportation Research and Development

基　　金：国家重点研发计划课题项目(2016YFC0802203)。

摘　　要：为尽可能提高土质边坡模型在数值模拟求解过程中的精度,在前人研究的基础上引申了3个影响边坡模型稳定性精度的主要问题,一是模型边界尺寸应该如何确定,二是初始应力场的求解方法应该如何选择,三是边坡模型的网格划分应遵循什么原则可以满足模型的计算精度。基于此,以多个学者研究的典型边坡案例为研究对象,采用FLAC3D对以上3个问题进行了分析并解决。首先,讨论了目前模型边界尺寸确定存在的问题,引入数值模型的复合位移作为判据之一与边坡稳定系数共同确定新的模型边界尺寸原则,在前人基础成果上对边界尺寸原则进行了局部优化,精简了计算模型,并通过实例验证其正确性;其次,讨论了目前初始应力场搭建存在的问题,通过模型稳定系数云图、塑性区应变增量、坡顶位移综合分析弹性求解与弹塑性求解初始应力场的区别,确定了不同的适用情况;最后,分析了目前网格尺寸划分存在的问题,建立不同高度不同网格密度的边坡模型,确定了一种较为合理的网格划分原则。以上3种情况均采用大量边坡模型进行了准确性验证,并采用极限平衡法中的Corps of Engieers#1法及Bishop法作为校核,结果显示,边坡模型计算结果与极限平衡法计算结果极为接近,并且复合位移、最大剪应变增量等判据均满足应力应变分布规律,在一定程度上提高了土质边坡模型在数值模拟求解过程中的精度,具有普遍适用性。In order to enhance the precision of the soil slope model in the process of numerical analysis as far as possible,3 major problems impacting the stability precision are extended on the basis of previous studies.One is how to determine the boundary size of the model,the other is how to choose the methods to solve the primary stress field,and the third is what principle should be followed in the grid division of the slope model to satisfy the computational precision.Based on this,the typical slope cases studied by many scholars are taken as the study object,and the 3 problems are analyzed and solved by using Flac3D.Firstly,the existing problems in determining the boundary size of the model are discussed,and the composite displacement of the numerical model is introduced as one of the criteria to determine the new model boundary size principle together with the slope stability coefficient.On the basis of previous results,the boundary size principle is locally optimized,the computational model is simplified,and its correctness is verified by case.Secondly,the problems existing in the construction of initial stress field are discussed,and the difference between elastic solution and elastic-plastic solution of primary stress field is determined by comprehensive analysis of model stability coefficient cloud chart,plastic zone strain increment and slope top displacement.Finally,the existing problems of mesh size division are analyzed,and a reasonable mesh division principle is determined by establishing slope models with different heights and mesh densities.A large number of slope models are used to verify the accuracy of the above 3 cases,and the Corps of Engieers#1 method and Bishop method of the ultimate equilibrium method are adopted as verification.The result shows that the slope model computation are consistent with the ultimate equilibrium method.

关 键 词：道路工程 精度研究 FLAC3D 土质边坡 边界尺寸 初始应力场 

分 类 号：TU452[建筑科学—岩土工程]