项目名称： 车辆动载和变温作用水平碎石沟风积沙硫酸盐盐渍土路基变形机理研究

项目编号： No.51508579

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑环境与结构工程学科

项目作者： 樊玲

作者单位： 中南大学

项目金额： 23万元

中文摘要： 实测西部风积沙硫酸盐盐渍土路基毛细水区含水量长时间饱和且含盐量较大，在车辆动载和变温作用下易发生一定程度液化、盐胀和溶陷。这是路基路面破坏的一个重要原因。依据振动固结排水理论提出盐渍土路基内增设水平碎石沟。水平碎石沟可加速路基振动排水，减小路基盐分富集和液化趋势，提高风积沙路基承载力。为此拟试验研究车辆动载和变温作用下风积沙硫酸盐盐渍土盐胀机理。基于颗粒流离散元PFC，结合传热传质理论和结晶动力学开发PFC-THMC 多场耦合模拟程序并对其进行数值模拟研究；拟模型试验研究车辆动载和变温作用下，水平碎石沟风积沙硫酸盐盐渍土路基排盐水、盐胀和压缩变形规律。拟采用PFC-THMC 和FLAC 耦合数值模拟研究水平碎石沟布置形式、间距、截面尺寸和埋深等参数对路基变形影响规律，获得水平碎石沟理论最优参数。本项目成果对西部盐渍土路基结构研究具有重要理论价值。

中文关键词： 盐渍土路；PFC-THMC；多场耦合；水平碎石沟；车辆动载；变温作用

英文摘要： In western China，There was measured saturated moisture content and high salt content in aeolian sulfate saline sand (ASSA) roadbed. Under vehicle dynamic load and temperature (VDLT) coupling action, the liquefaction, the salt expansion and salt dissolving happend easily. This is an important reason for the roadbed and pavement damage.It has been put forward that level gravel ditch is set in the saline soil roadbed according to the vibration consolidation drainage theory. For the level gravel ditch could increase roadbed water permeability and drainage, reduce roadbed salt concentration，improve the bearing capacity of the ASSA roadbed. Based on PFC, heat and mass theory and crystallization kinetics, the PFC-THMC coupling simulation program will be developed. Through VDLT coupling action, test and PFC-THMC numerical simulation, the salt expansion mechanism of the ASSA will be finished. Under VDLT coupling action, the Salt drainage, salt expansion and compression deformation rule will be researched by the level gravel ditch ASSA roadbed model test.By the PFC-THMC and FLAC coupling numerical simulation, the parameters of the level gravel ditch will be presented such as decorate form, spacing, setion size, buried depth etc.Then the optimum parameter will be suggested.In conclusion, the results have important theoretical value in western saline soil roadbed structure research.

英文关键词： saline soil roadbed;PFC-THMC coupling;Level gravel ditch;vehicle dynamic load;temperature coupling action