Abstract: In recent years,several new subway lines have been added in Nanjing,in order to explore the hidden problems of subsidence along the lines and surrounding areas caused by subway construction and operation,this paper utilizes the time series InSAR technique to obtain the subsidence rate field,cumulative subsidence and time series of subsidence in Nanjing,combines with the precipitation data to study the influence on the subsidence area,and conducts a detailed analysis of the typical subsidence areas of subway lines and their surroundings. The study shows that: Nanjing presents uneven subsidence,located in the Yangtze River diffuse zone,concentrated in the city center areas such as the coast of Jiangning district,Jianye district,Gulou district,etc., in which the subsidence is the most obvious along the central coast of Pukou district,with the highest annual subsidence of -55.9mm,covering an area of about 15.6km²; the subsidence of some lines of Metro Lines 2,4,7,and 10 is more obvious,and in the case of the Tingshan street in Pukou district and the Linjiang-Qingyao Sports park station in Pukou district for example,the highest cumulative settlement of -172.8mm; There is a relationship between Nanjing subway along the rate of settlement and precipitation. Under the impact of heavy rainfall,the pore water in the soil and the pore pressure of the gas contained increases to affect the settlement.

Key words: time series InSAR, Nanjing, settlement rate, subway