Deformation and Collapse Mechanisms of Water-Rich Soil Tunnels

This paper presents the Kuyu tunnel as an example to study the deformation characteristics and collapse mechanisms of Water-Rich Soil Tunnels (WRST) by means of field monitoring and numerical simulation. The obtained results indicated that deformation of the surrounding soil occurs mainly when the excavating face is between 2.0 and 0.5 of tunnel's diameter from the observation section. The deformation and collapse of WRST are controlled by the geological conditions (poor lithology and seepage-induced decrease in soil strength) and construction factors (overlong cyclic footage and delayed supporting enlarge the disturbance area). This study provides some useful information for the design and construction of WRST.