天津滨海新区新近沉积土确定及其工程特性研究

基于古海岸线及测年试验分析，对滨海新区上部陆相沉积土的形成年代进行研究，确定了该区新近沉积土的划分原则，并根据成因类型及沉积环境，进一步划分了新近沉积土的类别；根据土层厚度及底板埋深，查清了滨海新区新近沉积土的发育分布规律，并分析评价了该类土的工程特性。结果表明:滨海新区上部陆相沉积土形成年代小于4 000年，应将其划归为新近沉积土，与原新近沉积土共同组成该区新近沉积层；新划分原则下新近沉积土可分为洪泛新近沉积土、古河道新近沉积土及上部陆相新近沉积土三类，其厚度一般在1～2 m，底板埋深一般在3～4 m，工程性质较差，表现为较高含水量、较大孔隙比、较低抗剪强度、较高压缩性，地基承载力普遍在100 kPa左右。

Research on the identification and engineering characteristics of recently deposited soils in the Tianjin Binhai New Area

Based on the analyses of the paleocoast line and the dating test, the formation age of the upper terrestrial sedimentary soil in the Binhai New Area is studied, the principle of the recently deposited soils in the area is determined, and the classification of the recently deposited soils is further divided according to the genetic type and sedimentary environment. Based on the thickness of the soil layer and the depth of the floor, the development and distribution of the recently deposited soils in the Binhai New Area is investigated, and the engineering characteristics of this type of soil are analyzed and evaluated. The results show that formation age of the upper terrestrial sedimentary soil in the Binhai New Area is less than 4000 years. Consequently, the soil should be classified as recently deposited soil. Together with the original recently deposited soil, the recently deposited layer formed in the area. According to new classification principle, the recently deposited soils can be divided into three types: flooded recently deposited soil, ancient channel recently deposited soil and upper terrestrial recently deposited soil. The thickness of the recently deposited layer generally ranges from 1 to 2 m, and the floor depth generally ranges from 3 to 4 m. The engineering properties are poor, and are characterized by higher water content, larger void ratio, lower shear strength and higher compressibility, and the foundation bearing capacity is generally 100 kPa or so.