摘要
研究高填方地基在降雨条件下的入渗规律和增湿变形问题,对黄土沟壑区高填方的工后沉降形成机制探索和防排水设计具有重要意义。以某黄土高填方工程为背景,开展了填方区原位沉降监测和非饱和土的水–力特性室内试验,并基于流–固耦合数值方法,研究了不同降雨类型和不同压实度下高填方地基的入渗规律和增湿变形特性。结果表明:①黄土高填方地基因压实度不均和降雨类型差异,降雨影响深度为地表下2.0~7.0 m;②强降雨(暴雨、大雨)引起的增湿变形比为1.6%,大于中雨的1.2%和小雨的0.3%,不同压实度下(λ为0.88,0.93,0.98)强降雨引起的填方体增湿变形比分别为1.8%,1.5%,1.3%,采取适当的防排水措施对减小高填方地基增湿沉降的具有重要意义;③强降雨会引起填挖方交界面处产生过量的差异增湿沉降和剪切应变突变,这是导致填挖方交界处出现开裂和水毁的主要根源。
Investigating the infiltration law and moistening deformation(MD) of high fill embankment(HFE) under rainfall infiltration(RI) conditions is of great significance for the exploration of the formation mechanism of post-construction settlement and the design of water drainage for high fill in the loess gully area. Based on a loess high fill project, the in-situ settlement monitoring of the fill area and the water-force characteristic experiments of unsaturated soil are carried out. The fluid-solid coupling numerical method is employed to study the infiltration law and MD characteristics of HFE under different rainfall types and compaction degrees. The results show that:(1) Because of the unevenness of compaction degree and rainfall type, the RI depth below the surface of HFE changes from 2.0 m to 7.0 m.(2) The MD ratio caused by heavy RI(storm, heavy rain) is 1.6%, which is greater than 1.2% of moderate rain and 0.3% of light rain. The MD ratios caused by heavy rainfall under different compaction degrees(λ=0.88, 0.93 and 0.98) are 1.8%, 1.5% and 1.3%, respectively. It indicates that the appropriate waterproofing and drainage measures are important to reduce the MD of HFE.(3) Heavy RI can cause excessive MD differences and shear strain mutations at the interface of the fill and the original foundation, which are the main sources of cracking and water damage at the junction of the fill and the original foundation.
作者
朱才辉
李宁
ZHU Cai-hui;LI Ning(Institute of Geotechnical Engineering,Xi'an University of Technology,Xi'an 710048,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第5期845-854,共10页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51678484)
国家留学基金委项目(CSC:201808610061)
西安理工大学省部共建西北旱区生态水利国家重点实验室(2019KJCXTD-12)。
关键词
高填方地基
黄土沟壑区
降雨入渗
增湿变形
high-fill embankment
loess gully region
rainfall infiltration
moistening deformation
