Soil-water inrush induced shield tunnel lining damage and its stabilization: A case study

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.

Section: Analytical Prediction For Groundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Tang

Chen

Lei

et al. 2021

Self Cite

“…From equation (19), under the condition of space problem, the vertical frost heave displacement of each point on the ground surface caused by the ith freezing pipe can be expressed as…”

Section: Analytical Solution Before the Closure Of The Frozen Wallmentioning

confidence: 99%

“…In the study of Huang et al [15], the analytical solution of circular tunnel frost heaving force is derived on the basis of the nonuniform frost heaving of tunnel surrounding rock. In the study of Cai [16][17][18] based on single-pipe freezing theory, flat-panel freezing theory, and calculation equation of frost heave ratio of soil, considering the formation process of the frozen wall and using stochastic medium theory, a twodimensional analytical solution of ground frost heave in horizontal freezing period of tunnel is established and the analytical solution is improved in this study by considering the freezing point of soil and assuming the constant surface temperature of the freezing pipe, the analytical solution methods for the radius of the freezing front and the outer radius of the expanded area are determined and applied to practical engineering cases, and then, the reliability of the analytical solution was verified by comparing with the field measurement results [19].…”

Section: Introductionmentioning

confidence: 99%

Analytical Solution of Three‐Dimensional Heaving Displacement of Ground Surface during Tunnel Freezing Construction Based on Stochastic Medium Theory

Cai

et al. 2021

Many studies indicate that the heaving displacement during tunnel freezing construction can be regarded as a plane strain problem. However, due to the fact that many of the frozen pipes are placed obliquely in practical engineering, it should be a three-dimensional problem. Therefore, considering stochastic medium theory, the analytical solution of three-dimensional heaving displacement of ground surface during tunnel freezing construction is established, and the analytical solution is applied to the project case in Beijing. The calculation results show that, considering the inclination angle between the freezing pipe and the center axis of the tunnel, the maximum heaving displacement of the ground surface occurs at the tunnel center. When the inclination angle is equal to 0°, the analytical solution of three-dimensional ground surface heaving displacement is in good agreement with that of the two-dimensional prediction model, which further verified the reliability of the established analytical solution of the three-dimensional frost heave prediction model.

“…e urban subway project is often located in complicated geological environments with heavy traffic, intricate underground pipelines, many surrounding structures, and insufficient geological exploration. In addition, there is great uncertainty and high risk during the construction process [1], ascribing to technical limitations in underground construction within hard rock strata. At present, the research progress of construction risk in urban subway projects is relatively slow, and there are multiple problems as follows: (1) lack of information;…”

Section: Introductionmentioning

confidence: 99%

Identification and Assessment of Subway Construction Risk: An Integration of AHP and Experts Grading Method

Liu

et al. 2021

Qing Dao is one of the earliest cities that included the idea of subway construction into the city’s transportation plan. However, the construction period of a subway project is long, and the uncertainties caused by the geological conditions and surrounding environments are huge, thus a risk assessment method in subway construction is essential. To ensure the tunnel safety, many researchers have raised different methods for risk assessment. The process of risk assessment can be characterized in three steps: (1) data acquisition; (2) complete the uncertainty model; (3) evaluate the possible risk during the construction. This paper introduces a novel risk assessment method that combines the Analytic Hierarchy Process (AHP) and Experts Grading Method (EGM). The advantage of AHP is that it can quantify the qualitative factors, inspect and reduce the subjective influence to a certain extent, and make the evaluation more scientific. As for the EGM, simplicity and directness are the main characteristics. Assisted by this method, proper measures can be taken to eliminate the potential risk. The integrated method was implemented during the construction of Taishan Road Station of Qingdao Subway to evaluate the potential risk. With the help of this integrated method, the general risk sources during the construction period are well marked and the control measures corresponding to the risk sources are provided.