Experimental study on influence of ground rebound on tunnels caused by groundwater restoration

Abstract

In recent years, regional ground rebound phenomenon caused by the rising of groundwater level has been observed in an urban area in Japan such as Tokyo. This phenomenon might affect the underground structures constructed in those areas. In this study a centrifuge model test was carried out to investigate the fundamental mechanism of tunnel deformation and ground rebound during water rising process. In the centrifuge model test, two model tunnels were installed in different depths of clay ground in order to investigate the influence of ground depth on tunnel deformation. It is found that the relationship between ground surface displacement and elapsed time obtained from centrifuge model test shows similar tendency to the field measurement data. It is confirmed that deformation patterns of the two tunnels were different in the water rising process. This is considered to be due to the difference in deformation and pore water pressure in different layers of clay ground. Detail discussions on deformation mechanism of the two tunnels and pore water pressure distribution in clay are presented in this paper.