大气作用下膨胀土边坡的动态响应数值模拟  

Numerical simulation of dynamic response of expansive soil slope to atmospheric conditions

作　　者：陈建斌[1] 孔令伟[1] 郭爱国[1] 赵艳林[2] 

机构地区：[1]中国科学院武汉岩土力学研究所,湖北武汉430071 [2]广西大学土木建筑工程学院

出　　处：《水利学报》2007年第6期674-682,共9页Journal of Hydraulic Engineering

基　　金：国家重大基础研究前期研究专项(2003CCA02200);交通部西部交通建设科技项目(200631878530);中国科学院武汉岩土力学研究所领域前沿基金项目(Q110301)

摘　　要：采用热湿耦合非等温流方程,结合实际蒸发和植物蒸腾的边界条件,通过考虑水分迁移所引发的非饱和土应力变形行为,建立了大气-非饱和土相互作用模型。采用该模型,分析了在气候变化条件下,不同坡比和不同覆盖条件下非饱和膨胀土边坡的各种动态响应。计算结果表明,该模型能较好分析计算非饱和土表层的蒸发量及草皮对边坡土层含水率和变形的影响;采用分阶段变渗透系数的方法,能有效反映出降雨入渗和蒸发蒸腾过程中膨胀土所表现的不同渗透特性;而边坡的安全系数随气候变化而波动,降雨时边坡的稳定性比蒸发时低,蒸发可提高表层土体吸力,草皮覆盖亦有利于边坡的稳定性。Based on the equations of coupled heat-moisture anisothermal flow and the behaviors of stress- strain of unsaturated soil, a model expressing the interaction between atmosphere and unsaturated soil is established with the actual evaporation and vegetation transpiration adopted as the boundary condition. The model was applied to numerically simulate the dynamic response of expansive soil slope of various slope ratio and coverage to long-term action of atmosphere. It is found that by using this model the unsaturated soil surface evaporation and the effect of grass coverage on soil moisture and slope deformation can be well analyzed and the different infiltration behaviors of expansive soil in the process of rainfall infiltration and evapotranspiration can be reflected if the stage changeable permeabili is adopted. The slope safety factor fluctuates with the changes of climate. Moreover, under the condition of rainfall is lower than that of evaporation due to the increase of and the grass coverage is also helpful to improve the stability of the slope. ty coefficient method the stability of slope surface soil suction, and the grass coverage is also helpful to improve the stability of the slope.

关 键 词：大气-非饱和土相互作用模型 膨胀土边坡 动态响应 变渗透系数 数值模拟 

分 类 号：TU443[建筑科学—岩土工程]