The Research Of Dynamic Dewatering During Metro Station Construction Under Watered Sandy Conditon

The subway gradually becomes indispensable to people’s transportation along with the accelerating urbanization pace of China, which results in increased congestion of urban traffic. Many cities in China have or to be built new metro project, straining to meet soaring demand. As underground water affects the construction tremendously, It is very important to study the dynamic dewatering technology in the geological condition of watered sandy stratum. In this paper, taking Shenyang metro line two Shenyang station north as engineering background, subway station construction dynamic dewatering of watered sandy stratum in specific engineering geological and hydrogeological conditions had been studied, employing theoretical derivation, field test and numerical method. A series results had been obtained as the following.The decline of groundwater level in the process of water discharge calculation method, water level recovery process water discharge calculation method and the dewatering area in the plane change water discharge calculation method had been obtained, according to the principles of groundwater seepage and various types of single well and wells group dewatering process to maintain the stable water level water discharge calculation formula.Dewatering method had been determined, considering the geological condition of Shenyang north station, site construction conditions and economy benefit. Using the numerical method of fender pile on the influence of groundwater seepage, determined the precipitation correction coefficient. Subway station construction dewatering optimization design method had been obtained by using object function method, and Shenyang North Station dewatering scheme had been optimized, basing on this method. Three precipitation stage dewatering into stable time, steady precipitation and steady dewatering well number had been obtained, by introducing calculation and analysis in the dewatering process.Based on numerical method, three precipitation stages dewatering into stable time, ground subsidence reached stability requires time and stability after the subsidence value had been obtained by employing simulation analysis in dynamic precipitation process. And the fender pile effect on groundwater seepage path had been also considered as an influence factor.Dynamic dewatering management measures of subway station construction had been proposed, including including construction management organization, precipitation well dewatering operation management, real-time monitoring the entire dewatering process by establishing dynamic monitoring network.