上海地区的淤泥质粘性土,一般埋深地下3～20米。具有不良的工程地质条件,是造成建筑物地基变形的主要土层。长期来上海市区因过量抽汲地下水造成承压水的压力下降,各土层排水固结,市区地面急剧下沉。根据东区劳动公园土层分层沉降标的测量资料,在大量开采地下水时期,如1964～1966年,地面标总沉降量为46毫米,其中淤泥质粘性土的压缩量为27毫米,占总沉降量的59%。 Muddy cohesive soils in Shanghai are usually buried 3 to 20 meters deep underground. Poor engineering geological conditions are the main soil layers that cause deformation of the foundations of buildings. In the long-term Shanghai area, the pressure of confined water was reduced due to excessive water pumping of groundwater, drainage of the soil layers was consolidated, and the ground in the urban area drastically sank. According to the measurement data of stratified subsidence targets in the Labor Park of Dong District, in the period of large-scale exploitation of groundwater, such as 1964-1966, the total subsidence on the ground surface was 46 mm, of which the compressive capacity of silty clay soil was 27 mm, which accounted for the total settlement. 59%.