随着四个现代化的发展,高层建筑不断兴建,根据高层建筑的特点和要求进行沉降观测,已愈来愈为人们重视。高层建筑的基础有桩基础、箱形基础和桩基加箱基三种,上海地区软土地基多采用后两种。上海地区软土地基上建造箱形基础高层建筑一般有三个特点:1)箱形基础埋置较深,一般为5米或更深些;2)由于上海地区地下水位较高,平均常年地下水水位在地表面以下70厘米,因而基础施工均采用井点降水来降低地下水水位,以便开挖基坑和基 With the development of four modernizations, the construction of high-rise buildings has continued, and settlement observations based on the characteristics and requirements of high-rise buildings have become more and more important. The basis of high-rise buildings is pile foundations, box foundations, and pile foundations plus box foundations. The latter two types of soft soil foundations are used in Shanghai. The construction of box-shaped high-rise buildings on soft soil foundations in Shanghai generally has three characteristics: 1) The box-shaped foundations are buried deeper, generally 5 meters or more; 2) Due to the high groundwater level in Shanghai, the average annual groundwater level is 70 cm below the surface of the ground, so the foundation construction uses well-point precipitation to reduce the groundwater level in order to excavate foundation pits and foundations.