陕西省西咸新区黄土场地海绵设施渗漏对建筑物的影响

黄土场地近建筑物海绵设施建设时常铺设防渗膜,以避免雨水入渗引起地基变形破坏。施工过程中防渗膜的意外破损时有发生,讨论近建筑物基础防渗膜局部破坏引起的工程风险有助于推进类似地区海绵城市建设。以陕西省西咸新区海绵城市建设中某一典型工程为依托,采用Geo Studio软件对周边建筑物典型海绵设施发生的渗漏问题进行数值模拟分析,得到了渗漏后土体饱和度、基础沉降和地基土应力分布变化特性,分析了渗漏点雨水入渗对地基的影响。结果表明:渗漏会使地基产生不均匀沉降; 渗漏点距基础边缘水平距离越近,所产生的附加沉降越大,渗漏导致的最大沉降量约为4 mm,满足《建筑地基基础设计规范》(GB 50007—2011)要求。另外,当渗漏点距基础边缘水平距离大于1 m时,渗漏对地基强度的影响迅速降低; 当距离大于3 m时,渗漏对地基的影响可以忽略。在本文工程背景下,渗漏导致地基破坏可能性较小。

Impact of Leakage of Sponge Facilities on Building at Loess Site in Xixian New Area of Shaanxi Province,China

It always extends anti-seepage membrane for sponge facilities at loess site to avoid uneven settlement of foundation caused by rainwater infiltration. Accidental damage of anti-seepage membrane occurs in the construction process frequently. Discussing the risk caused by the local damage of anti-seepage membrane near the foundation of buildings is helpful to promote the construction of sponge city in similar areas. Based on a typical practical project in sponge city construction of Xixian new area in Shaanxi province, Geo Studio software was used to simulate leakage impact of sponge facilities near the building and to obtain the characteristics of soil saturation, foundation settlement and variation of soil stress distribution in the foundation after leakage; furthermore, the influence of rainwater infiltration at leakage point on the foundation was appraised. The results show that the leakage could cause uneven settlement of foundation; the closer the horizontal distance between leakage point and foundation edge, the greater the additional settlement; and the maximum settlement is about 4 mm, meeting the requirements of Code for Design of Building Foundation(GB 50007—2011). Besides, the influence of leakage on the foundation strength decreases rapidly when the horizontal distance between leakage point and foundation edge is more than 1 m; while the influence could be ignored once the horizontal distance is larger than 3 m. Under the background of the project, the possibility of foundation failure caused by leakage is small.