A groundwater flow model for excavation of coastal earthen sites: case study Jintoushan site, China

Abstract

Most of the earthen sites in coastal areas of South China are rescue excavations. According to the statistics, the main environmental geological hazards of the protection of original earthen sites is the water seepage caused by groundwater damages, especially during typhoon season (Jun.-Sep.). The article takes the Jingtoushan site of Zhejiang province, China as an example to establish a hydrogeological model, which was formally started excavation on June 3, 2018. The average depth of Neolithic remains in this site is 7m and the scheme is to design a rectangular foundation pit with row pile supporting structure. By collecting and analyzing the local meteorological data (precipitation, evaporation, etc.) and geological conditions of the site, the study simulates Jingtoushan site using the finite difference code of Visual MODFLOW to calculate the distribution of original groundwater and the variation law of seepage field in site area during construction period. The models are calibrated and verified through survey data using permeability and seepage model. The new numerical simulation method can be used to guide the excavation and construction of other earthen sites.