摘要
本文以沈阳地区典型的非饱和粉质黏土基坑作为研究对象,以降雨期内现场实测数据为基础,分析土体的负孔隙水压力及含水量的动态变化情况,并拟合土水特征曲线(SWCC)数学模型,最后将水土特征曲线引入到非饱和土抗剪强度理论模型中。研究结果表明:降雨对粉质黏土基坑土水特性的主要影响范围为表层0.9m左右,且该地区粉质黏土应用VG模型拟合效果最好。降雨期间,基坑安全系数前期下降较快,后期趋于平缓,且下降速度随着降雨强度的增加而减小,当降雨强度大于粉质黏土的渗透系数时,安全系数趋于一致。降雨量相同时,均匀型降雨较不均匀降雨对基坑的稳定性影响更大,安全系数下降速度快且持续时间长,但各种类型降雨的最小安全系数大致相同。
The deep excavation in the typical unsaturated silty clay in Shenyang area is studied in this paper. The dynamic changes of negative pore water pressure and moisture content in the soil were analyzed based on the monitoring data during the rainfall period, soil and water characteristic curve(SWCC) mathematical model was fitted, and finally, the SWCC was introduced into the theoretical shear strength model of unsaturated soils. The results show that the main influence depth of rainfall on soil and water characteristics of silty clay excavation pit is about 0.9 m in the surface layer, and the VG model is most suitable for the silty clay in this area. The safety factor of excavation pit decreases rapidly in the early stage and tends to be gentle in the later stage during the rainfall period, and the decline rate decreases with the increase of rainfall intensity;when the rainfall intensity is greater than the permeability coefficient of silty clay, the safety factor tends to be the same. With the same rainfall quantity, uniform rainfall has a greater impact on the stability of the pit than non-uniform rainfall, and the safety factor decreases faster and lasts longer. However, the minimum safety factor of all types of rainfall is roughly the same.
作者
孙振华
姜闯
辛全明
邵凌峰
Sun Zhenhua;Jiang Chuang;Xin Quanming;Shao Lingfeng(China Northeast Architecture Design&Research Institute Co.,Ltd.,Shenyang 110000,China;Shenyang Geotechnical Investigation&Surveying Research Institute Co.,Ltd.,Shenyang 110000,China;Geotechnical Engineering and Underground Space Research Center of Liaoning Province,Shenyang 110000,China)
出处
《工程勘察》
2021年第11期6-12,47,共8页
Geotechnical Investigation & Surveying
基金
中建股份科技研发计划资助项目(CECEC-2014-Z-16,CSCEC-2017-Z-37)
东北院科技研发计划资助项目(DBY-KY-05)。
关键词
基坑边坡
降雨入渗
非饱和粉质粘土
土水特征曲线
安全系数
excavation pit slope
rainfall infiltration
unsaturated silty clay
soil and water characteristic curve(SWCC)
safety factor
作者简介
孙振华(1981-),男(汉族),辽宁沈阳人,博士研究生,高级工程师.
