变透水边界与起始坡降下软土路基固结模型  

Consolidation Model for Soft Soil Subgrade Considering the Threshold Hydraulic Gradient and Variable Permeable Boundary

作　　者：杨强 魏征 YANG Qiang;WEI Zheng(China Railway Design Corporation,Tianjin 300308,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308

出　　处：《铁道工程学报》2024年第6期40-44,51,共6页Journal of Railway Engineering Society

摘　　要：研究目的:路基沉降问题是引起铁路、公路等基础设施发生工程事故的主要原因。为提高软土地区路基土沉降预测水平,本文考虑土体的非达西渗流效应、土体边界透水能力的变化以及变形非线性特征,建立相应的分段线性化固结模型。其中,起始坡降渗透模型用来反映土体的非达西渗流过程,连续排水边界用来描述土体边界透水性能的变化,e-lg(av0)关系用来表示土体的非线性变形特征。然后,应用一些算例分析探讨边界透水性能变化、土体非线性变形以及非达西效应下土体的固结行为,以期为软土路基工程工后沉降预测提供理论支撑。研究结论:(1)土体的非达西效应越强(即起始坡降值越大),边界透水性能越差(即连续排水界面参数越小),相同时刻下的固结滞后现象越明显;(2)起始坡降值能同时影响固结过程及最终结果;(3)连续排水边界和起始坡降下初始压缩系数对沉降过程的影响比较显著;(4)本文固结模型可模拟深厚软土路基的沉降过程,相关结论可应用于深厚软土的堆载排水加固过程。Research purposes:The problem of roadbed settlement is the main cause of engineering accidents in infrastructure such as railways and highways.In order to improve the settlement prediction level of roadbed soil in soft soil areas,considering the non-Darcian flow of soil,the variable drainage boundary,and the nonlinear deformation characteristics,this paper proposes the corresponding piecewise-linear consolidation model.Among them,the seepage model with the threshold hydraulic gradient is used to reflect the effect of non-Darcian flow,the continuous drainage boundary is used to describe the changes in the permeability performance of soil boundaries,and the relationship of e-lg(av0)is used to represent the nonlinear deformation characteristics of soil.Then,some examples are used to analyze the change of boundary permeability,nonlinear deformation of soil and consolidation behavior of soil under non-Darcian effect,in order to provide theoretical support for the prediction of settlement after construction of soft soil roadbed.Research conclusions:(1)The stronger the non-Darcian effect of soil(i.e.the larger the value of the threshold hydraulic gradient),the worse the boundary permeability(i.e.the smaller the interface parameter),and the more obvious the phenomenon of consolidation hysteresis at the same time.(2)The value of the threshold hydraulic gradient can simultaneously affect the consolidation process and the final result.(3)The initial compression coefficient considering the threshold hydraulic gradient and the continuous drainage boundary has a significant impact on the settlement process.(4)The proposed consolidation model can simulate the settlement process of deep soft soil subgrade,and the relevant conclusions can be applied to the process of pile loading drainage reinforcement of deep soft soil.

关 键 词：软土 路基 固结 起始坡降 连续排水边界 

分 类 号：TU43[建筑科学—岩土工程]