Predicting Response of Constructed Tunnel to Adjacent Excavation with Dewatering

Abstract

This paper proposes a new method for predicting the displacement and internal force of constructed tunnels induced by adjacent excavation with dewatering. In this method, the total excavation-induced additional stress on the constructed tunnel is derived by superposing the additional stresses induced by excavation unloading and dewatering effects. The additional stress induced by unloading effect is calculated using Mindlin’s solution. The additional stress induced by dewatering effect is calculated using the principle of effective stress and the Dupuit precipitation funnel curve. With the beam on elastic foundation method, the total additional stress is then used for calculating the tunnel displacement and internal force caused by adjacent excavation with dewatering. Based on three well-documented case histories, the performance of the proposed method is verified. Moreover, a parametric analysis is also performed to capture the effects of excavation depth, tunnel-to-excavation distance, initial water level, excavation plan view size, and specific yield on the responses of the constructed tunnels. The results indicate that the effect of excavation depth on the tunnel maximum vertical displacement, maximum bending moment, and maximum shear force is more significant at an excavation depth greater than the cover depth of the constructed tunnel. The tunnel maximum vertical displacement, maximum bending moment, and maximum shear force decrease nonlinearly with an increase in the tunnel-to-excavation distance and the initial water level. Among the investigated parameters, the excavation dimension in the tunnel longitudinal direction affects most the tunnel responses. The effect of specific yield on the tunnel displacement and internal force induced by adjacent excavation with dewatering becomes more obvious as increasing the initial water level and excavation depth.

Temporal-Spatial Characteristics of Ground and Pile Responses to Twin Shield Tunneling in Clays

“…Pile group responses to tunneling can vary slightly, depending on the characteristics of the stratum in which tunneling occurs [34][35][36]. Studies on pile group responses to tunneling in a clay stratum are available in the literature.…”

“…Cattoni et al [38] investigated the coupled hydromechanical processes related to shield tunneling in soft clays. A new method for predicting the displacement and internal force of constructed tunnels induced by adjacent excavation with dewatering was proposed by Guo et al [35]. Using the force relaxation technique and finite difference program, Shiau et al [39] analyzed the ground settlements induced by circular tunneling in soft clay.…”

Experimental Investigation into Limit Void Ratio Characteristics of Calcareous Sands considering Various Factors

“…It is a state parameter indicating how dense a given sand sample or deposit is with respect to its range of possible densities. It has a governing influence on strength and stability of sand in filling engineering, such as embankment, retaining wall, and ground improvement [21][22][23]. Nevertheless, the determination of the maximum and minimum void ratios is the prerequisite for calculating the relative density.…”

Loading Behavior and Soil-Structure Interaction for a Floating Stone Column under Rigid Foundation: A DEM Study

“…Laboratory tests can overcome those disadvantages, which simulate field structure in small scale. Experimental study on behavior of stone column can be carried out by various parameters like shear strength of soft clay, loading conditions, and diameter and spacing of stone columns [16][17][18][19][20][21]. Obvious bulging deformation can be observed when only pile is loaded; the maximum bulging location is 0.5 times the column diameter from the top [20].…”