摘要
为了分析多层结构土质边坡在不同降雨条件下的渗流过程以及稳定性变化规律,基于降雨入渗机理以及均质土体降雨入渗深度理论计算公式,提出了多层结构土质边坡降雨入渗深度及其稳定性计算方法,利用该计算方法分析不同降雨条件下雨水的入渗深度,同时应用数值分析方法计算多层结构土质边坡降雨入渗深度及其稳定性。研究结果表明:建立的降雨强度与降雨时间共同影响下的多层结构土质边坡雨水入渗深度理论计算公式的计算结果与数值分析得到的结果基本一致,表明该公式能较好地反应多层结构土层边坡降雨入渗过程;降雨入渗过程中靠近坡面的土层体积含水率、孔隙水压力增长速度较快,并且在土层交界面处,土层体积含水率、孔隙水压力变化幅度比较大,且靠近坡面的土层体积含水率首先达到饱和状态,随后第2层土体的含水率也逐渐达到饱和状态;降雨入渗过程中边坡安全系数随着降雨入渗深度的增加而不断降低,并且在湿润锋到达土层分界面时,安全系数有突变现象,由于不同土层之间渗透系数的差异性,使得雨水在土层分界面处易形成平行于坡面的渗流,进而导致边坡安全系数出现较大范围的波动,此时边坡最容易发生失稳破坏。
In order to analyze the infiltration process and stability variation of soil slope with multilayer structure under different rainfall conditions, a method for calculating the rainfall infiltration depth and stability of multilayer soil slope were proposed based on rainfall infiltration mechanism and theoretical calculation formula of rainfall infiltration depth of homogeneous soil. The proposed method and numerical analysis method were used to calculate the depth and stability of rainfall infiltration and stability of soil slope with multilayer structure. The results show that the formula for calculating the infiltration depth of multilayer slope under the influence of rainfall intensity and rainfall time duration is established. The results obtained from theformula are basically consistent agree with the numerical analysis results. That is to say, the formula can better reflect the rainfall infiltration process of the multilayer soil slope. In the process of rainfall infiltration, the volumetric water content and pore water pressure near the slope surface dramatically increase and change greatly at the interface of soil layer. Meanwhile, the slope surface reaches saturation firstly, and the volume water content of second layer soil reaches saturation subsequently. The safety factor of slope decreases with the increase of rainfall infiltration depth in the process of the rainfall infiltration. The safety factor changes suddenly when the wetting front reaches the soil interface. On account of the difference of permeability coefficients between different soil layers, it is easy to form seepage flow parallel to the slope surface at the interface of the soil layer, thus causing a wide range of fluctuation of the slope safety factor. The slope is prone to be failure this moment.
作者
胡庆国
袁宁
刘登生
何忠明
HU Qing-guo, YUAN Ning, LIU Deng-sheng, HE Zhong-ming(School of Civil Engineering and Architecture, Changsha University of Science ~ Technology, Changsha 410114, Hunan, Chin)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2018年第2期67-74,共8页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51678073
51508042)
湖南省重点研发计划项目(2016SK2023)
关键词
道路工程
降雨入渗
数值分析
土质边坡
稳定性
road engineering
rainfall infiltration
numerical analysis
soil slop
stability
