深厚软土地区基坑开挖主要工程地质问题与对策

在东南沿海地区的城市建设中为了节约土地资源,缓解城市生活和交通拥挤状况,高层建筑的基坑开挖深度越来越大,同时城市地铁结点工程(车站、特别是换乘站)建设也多采用深基坑施工方法,而且呈现多层开发的趋势,城市地下工程建设已进入快速发展时期。然而这一地区广泛分布全新世新近沉积的淤泥质软土,由于其土体的性质软弱,在基坑施工中难度很大,易发生基坑边坡失稳、坑底隆起、突泥突水和支护结构失效等工程地质问题,诱发基坑周围地面沉陷、不均沉降及相邻建筑物开裂、破坏等不良环境效应。本文针对软土地区深基坑施工中可能出现的工程地质问题及不良环境效应问题进行深入研究,分析影响基坑安全的主要影响因素,提出了一些具体处置方案和防治措施,通过软土区实际基坑施工验证,是成功有效的,具有示范意义。

The Research of Main Engineering Geological Problems and Prevention Measures in the Pit Construction of Soft Soil Areas

In order to solve the problem of city residents live and heavy traffic, the underground engineering construction have entered a rapid development period in the city of southeast coastal regions. The excavation depth of high rise building pit is more and more, the pit is a kind of common construction method in the node projects construction of the subway, and the pit presents a multilayer development trend. However, muddy soft soil of the Holocene is widely distributed in coastal area. Because the properties of soft soil is poor, the construction of pit is very difficult, it is easy to occur some engineering geological problems, such as instability of pit slope, bursting mud and water and the failure of supporting structure, etc. Which bring out some adverse environmental effects, such as ground subsidence, uneven settlement, buildings cracking and damage around the pit. Some engineering geological problems and adverse environmental effects in deep pit construction had intensively been studied in soft soil area, the main factors of affecting foundation pit safety had been analyzed, and the specific prevention measures had put forward in this paper. The prevention measures is successful by the verification of construction of practical foundation pit in soft soil area.