Abstract: The foundation excavation of Dongtinghu Road Station of the Suzhou Rail Transit is located on Qianjin East Road, which is one of the main transportation lines of Kunshan City. A thick layer of peaty cohesive soil is deposited at the proposed excavation project site. The monitoring of the response of the supporting structure and the adjacent ground subsidence due to the excavation are of great importance to the safety of the excavation as well as the adjacent utilities. A construction monitoring program was developed based on the site geological, hydrological conditions and the surrounding environment constrains. The following conclusions are obtained: 1) The shape of the horizontal displacement of the retaining structure induced by the foundation excavation is similar to a “shuttle” shape. The maximum horizontal displacement value gradually increases with the excavation depth, and the position of the maximum horizontal displacement gradually shifts to the lower portion; 2) The top of the retaining structure gradually produces an upward vertical displacement (the wall rises), and at the same time produces a roughly outward and symmetrical horizontal displacement; 3) The displacement characteristics of the enclosure wall body and the top of the wall further cause the release of the axial force of the upper support on the enclosure wall and the increase of the axial force of the lower support; 4) The cross-sectional curve of the ground subsidence induced by the excavation is in the shape of a “double bowl”, and the response of the underground utilities within the scope of the "double bowl" should be paid attention to during the construction.

Key words: Foundation Excavation, Peaty Soils, Ground Subsidence, Supporting Walls