基于连续-离散耦合的公路拓宽路基变形及换填处治宏细观分析

发布时间：2018-01-20 11:01

本文关键词： 道路工程道路拓宽连续-离散耦合土体变形轻质土　出处：《公路交通科技》2017年10期 　论文类型：期刊论文

【摘要】：公路拓宽改建是适应交通运输能力增长的重要应对措施,而由于新旧路基材料性质不同导致的差异沉降和路基稳定性是该类工程建设过程中需重点关注的关键问题。针对公路拓宽改建的工程问题,采用连续-离散耦合数值分析方法,对路堤边坡断面建立二维模型,连续、离散网格区域分别采用有限差分连续元和颗粒离散元进行建模。基于模型不平衡力变化规律、细观接触力链与宏观变形特征、细观配位数与土体沉降机理等模拟结果,从宏观和细观两个角度协同分析拓宽路堤差异沉降及其对路基变形的影响,并针对采用轻质土方式进行道路拓宽的工程效果进行了模拟分析。结果表明:(1)细观颗粒的不平衡单元面积比参数可与宏观不平衡力共同判定计算模型的收敛性及计算结果的合理性;(2)路基拓宽前后,细观接触力的分布规律可表明土体宏观位移变化的发展方向;(3)模型中细观颗粒在计算过程中的配位数变化可解释土体沉降变形机理;(4)采用轻质土换填方式拓宽路基,可大幅减少路基的沉降变形及新旧路堤的差异沉降,表明该技术应用于软土区域的公路拓宽工程具有显著优势;(5)连续-离散耦合分析方法可反映公路路基变形破坏的力学机制及差异沉降产生的内在本质,可在岩土工程灾害防控措施及其机理研究方面进一步推广应用。
[Abstract]:Road widening is important to measure growth of the transport capacity due to differential settlement of subgrade caused by different material properties and stability of subgrade is the key problem need to focus on the process of the project construction. Aiming at the problems of highway widening engineering reconstruction, the method of continuous and discrete coupling, the embankment slope section is established the two-dimensional model, continuous, discrete and continuous grid divided element particle discrete element modeling using finite difference model. Based on the unbalanced force variation of micro contact force chain and macro deformation characteristics, microscopic mechanism of the simulation results of coordination number and soil settlement, from the macro and micro two aspects of collaborative analysis of widening effect and the deformation of subgrade embankment settlement difference, and the way of light soil road widening project was simulated and analyzed. The results show that: (1) micro particles of unbalanced rationality of unit area ratio can and macro imbalance force to determine the convergence of calculation model and calculation results; (2) before and after the subgrade widening, distribution of micro contact force can indicate direction change of soil macro displacement; (3) in the model of micro particles in the process of calculation of the coordination number changes can explain the settlement deformation mechanism; (4) the use of lightweight soil replacement method of subgrade widening, can significantly reduce the deformation difference between old and new embankment settlement of subgrade settlement, show that the technology is applied in the soft soil area of the highway widening project has significant advantages; (5) continuous discrete coupling the analysis method can reflect the intrinsic mechanism of the settlement and difference of deformation and failure of highway subgrade, can be in the field of geotechnical engineering disaster prevention and control measures and mechanism of further application.

【作者单位】：中电建路桥集团有限公司;交通运输部公路科学研究院;北京科技大学土木与资源工程学院;
【基金】：北京市科委科技北京百名领军人才培养工程项目(Z151100000315014)
【分类号】：U418.5
【正文快照】： 0引言近20年来,我国公路尤其是高速公路建设发展迅速,随着交通流量的显著增加,早期建设的公路工程已很难满足社会经济发展的需要,因此,公路拓宽改建项目越来越多。但新旧公路路基、路堤作为不同时期建设的工程结构,从有效承载及安全运营角度考虑,仍存在一系列必须面对的技术问

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