Deformation Characteristics and Influence Factors of a Shallow Tunnel Excavated in Soft Clay with High Plasticity

Advances in Civil Engineering

Zhu

et al. 2021

Self Cite

The problems faced by subway stations in the construction process are more complex than those by overground buildings. Therefore, the construction risk for such structures is highly unpredictable and the risk management is difficult. Building information modeling (BIM) technology has strong visualization, simulation, and integration characteristics that make it conducive to the development of a risk early warning system for underground engineering. According to the functional requirements of risk early warning for subway stations, a risk early warning system based on a BIM real-time construction model is designed in this study for a subway station construction. The operation process of the risk early warning system is established through the grey prediction method to propose the operation method of the early warning system. The early warning system is applied to the Xiangjiang New Town Station of Changsha Metro Line 4 in China to verify its feasibility.

Section: Information Integration Managementmentioning

confidence: 99%

Design and Application of Risk Early Warning System for Subway Station Construction Based on Building Information Modeling Real‐Time Model

Tang

Advances in Civil Engineering

Zhu

et al. 2021

Self Cite

“…Assume that the required s w is approximately 8 m and the maximum permeability coefficient of a confined aquifer k is 36 m/d based on field conditions. The influence radius R is calculated as 480 m using Equation (5). The model range is supposed to extend to more than 480 m from the pit center.…”

Section: Initial/boundary Conditionsmentioning

confidence: 99%

“…Most excavation depths in urban areas have reached more than 20 m at present [2,3]. In the eastern coastal areas of China (e.g., Shanghai, Tianjin, and Hangzhou), considerable amounts of Quaternary marine and estuarine sediments have been alternately deposited, forming an alternating multi-aquifer system (MAS) composed of low-permeability clay, silt, saturated sand, and gravel layers [4][5][6][7]. Besides, these deposits frequently have high water tables as approaching the coast [8,9].…”

Section: Introductionmentioning

confidence: 99%

Dewatering Characteristics and Inflow Prediction of Deep Foundation Pits with Partial Penetrating Curtains in Sand and Gravel Strata

Liu

Cao

et al. 2019

Water

Self Cite

The dewatering of deep foundation pits excavated in highly permeable geology usually requires waterproofing technologies to relieve groundwater flow. However, no effective prediction formula is yet available for determining water inflow in the presence of partial penetrating curtains. In this study, a dewatering project with partial penetrating curtains is analyzed via a finite difference method to show evident three-dimensional (3D) seepage characteristics. The standard curve and distortion functions are established under the assumption of an equivalent well by quantifying the blocking effects; thus, the empirical inflow prediction formulas for steady flow are further developed. Moreover, a dewatering design method based on the prediction formulas is proposed and applied to the field dewatering project in sand and gravel strata. Measured results show that dewatering efficiency is considerably enhanced by 3D flow, forming appropriate pressure distributions for dewatering construction. The uplift pressure below the pit bottom is controlled within a 25% safety margin to verify the reliability of the design method.

“…erefore, it is of great significance to predict ground movements induced by tunneling, especially for the cases of tunneling under intense buildings, in order to assess the potential correlated damage of surface structures [1,[10][11][12]. e development of prediction methods to calculate tunnel-induced ground movement is among the hottest topics in tunnel engineering [13]. A large number of research efforts have been paid with respect to methods for predicting tunneling-induced ground movements.…”

Section: Introductionmentioning

confidence: 99%

Study on the Generalized Displacement Boundary and Its Analytical Prediction for Ground Movements Induced by Shield Tunneling

Tang

Chen

Advances in Civil Engineering

et al. 2021

Self Cite

The process of shield tunnel excavation would inevitably cause surrounding ground movement, and excessive displacement in the soil could lead to large deformation and even collapse of the tunnel. The methods estimating convergence deformation around tunnel opening is summarized. Then, a universal pattern of displacement boundary condition around the tunnel cavity is originally introduced, which is solved as the combination of three fundamental deformation modes, namely, uniform convergence, vertical translation, and ovalization. The expression for the above-mentioned displacement boundary condition is derived, by imposing which the analytical solution for ground movements, based on the stress function method, is proposed. The reliability and applicability of this proposed solution are verified by comparing the observed data in terms of surface settlement, underground settlement, and horizontal displacement. Further parametric analyses indicate the following: (1) the maximum settlement increases linearly with the gap parameter and the tunnel radius, while it is negatively related to the tunnel depth; (2) the trough width parameter is independent of the gap parameter and the radius, while it is proportional to the tunnel depth. This study provides a new simple and reliable method for predicting ground movements induced by shield tunneling.