硫酸腐蚀填土地基的勘察与地基处理

EXPLORATION AND TREATMENT OF A SULPHURIC ACID-CORRODED FILLING GROUND

本文为一硫酸腐蚀填土地基勘察、设计、施工实例总结。受硫酸腐蚀填土厚6—10m,松密不均,强度低,容许承载力值(6—13)×10kPa,不宜作天然地基土。填土下为不透水亚粘土层,pH为3.7的酸性废水被滞留在填土中,地下水位离地表最浅处仅1.5m。酸性地下水具结晶及分解性复合侵蚀性。对于这种地基土地基处理目前尚无章可循。该地基处理采用强夯加固填土、挖砂石盲沟降低地下水位、疏通排污管道,切断地下水补给来源等方案。地基处理后施工勘察,进行动力触探,静力触探、标准贯入试验及现场荷载试验,搜集各种数据,提供设计依据。经采用防腐措施、基础浅埋进行建筑施工,建筑物经4年仍无异常变化。

This paper presents a case study of the exploration, design and construction of a sulphuric acid-corroded filling ground. The sulphuric acid-corroded fill is 6-10 m thick, not evenly condensed, poor in strength, its allowable load-bearing capacity ranging from 60 to 130kPa, and it is not appropriate to treat as natural ground. Under the filling soil is unpermeable loam, acidic waste water with pH value being 3.7 is detained in the fi11ing soil, and the underground water table is only 1.5 m below the surface in the most shallow position. The acidic underground water is of decompositional and crystallizable composite erosion. There is no rule and regulation to follow on the treatment of such ground. For the treatment of this ground, following steps are taken: strong ramming to reinforce the fill,digging sand ditches to lower the ground water level, dredging drainage pipeline to cut off the recharge source of underground water etc. After the ground has been treated, exploration is conducted while construction, including static sounding, dynamic sounding, standard penetration test and live loading test etc, various kinds of data are collected to support the designation. When construction is carried, anticorrosive measures are taken, the foundations are laid shallowly. The buildings on this ground have. undergone through 4 years without abnormal changes.