Study on Excavation Sequence of Pilot Tunnels for a Rectangular Tunnel Using Numerical Simulation and Field Monitoring Method

Li, Shuobiao; Zhang, Yonggang; Cao, Mingyang; Wang, Zenian

doi:10.1007/s00603-022-02814-x

Cited by 35 publications

(15 citation statements)

References 31 publications

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“…Formation Mechanism. Landslides are a natural disaster resulting from rainfall, specific lithological characteristics, human activities, earthquakes, hydrology, and other conditions [9,[40][41][42][43][44]. In the "red layer" area, landslides can be divided into low soil strength landslides and high rock strength landslides [45,46].…”

Section: Investigation and Analysismentioning

confidence: 99%

Research on Internal Structure and Mechanism of Landslide Based on Hydrogeophysical Investigation (Quan’an Landslide, Southwest China)

Wang

et al. 2022

Geofluids

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The survey area is located in the planning area of Longquan national urban park, with frequent human activities, numerous water conservancy, transportation projects, and frequent geological disasters such as landslides. The Red Mudstone has low strength and easy to soften in the case of water, and it is very prone to landslide in rainy season. At present, there are many studies on Red Mudstone Landslides, but most of them are analyzed by geological means, and the monitoring process is also dominated by surface deformation and settlement; there is less analysis with hydrogeological that is caused by rainfall and human activities. For Red Mudstone Landslides, to effectively reveal and analyze the process of the Slip Mechanism, we need to carry out the characteristics of hydrogeological structure and underground physical structure, and compare with surface monitoring and point geological structure. In this study, a one-year field survey and hydrogeophysical survey were carried out. Combined with the characteristics of environmental geology, the geophysical forward modeling problem based on finite element method was used to verify the influence of rainfall on the electrical characteristics of underground media. The smoothness constrained least square method and three-dimensional unstructured grid method are used to interpret the ERT data, analyze the abnormal patterns of electrical structure of landslide in different seasons, and correspond well with the GPR data. According to the characteristics of surface vegetation and weathering, as well as the displacement and settlement monitoring after landslide, the spatial characteristics of red bed landslide are revealed, and the relationship between landslide, rainfall, and human activities is clarified.

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Section: Investigation and Analysismentioning

confidence: 99%

Research on Internal Structure and Mechanism of Landslide Based on Hydrogeophysical Investigation (Quan’an Landslide, Southwest China)

Wang

et al. 2022

Geofluids

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“…The numerical conformal mapping methods include series expansion method, variational method, boundary integral method and Symm's method, etc [7]. The series expansion method is widely used to achieve the approximate conformal mapping [8][9][10]. This type of method expands the conformal mapping functions into finite series.…”

Section: Introductionmentioning

confidence: 99%

Numerical conformal mapping for underground tunnels with arbitrary shapes based on Symm’s method

Chengzhang,

Cheng,

Jiang

2023

Preprint

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Conformal mapping technique is important in theoretical analysis and numerical computation for the fields of stress and displacement, since that these computations for tunnels with arbitrary shapes are always based on it. In general, a tunnel with arbitrary shape has no analytical solution for conformal mapping. Therefore, the study of numerical method for the conformal mapping has great significance. The basic functions of numerical conformal mapping are given based on Symm’s method. Furthermore, the inverse mapping functions were deduced firstly according to the relationships between the boundary nodes in physical and mapped plane. Compared to the other numerical methods, the presented method has some advantages such that, it is simple in concept to be understood, and can give the mapping function without iteration process. The method can be used to the numerical forward and inverse conformal mappings for multiple underground tunnels with arbitrary shapes in finite and infinite domains. With the help of method of fundamental solutions, the interpolation equations were proposed for multiple underground tunnels with arbitrary shapes. Finally, several numerical examples for the groups of U-shaped and rectangle tunnels have been given to verify the effectiveness of this method. The numerical results can convergent to real cases, which show that the proposed method has the properties of high accuracy and strong adaptability.

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“…The quasirectangular shield tunnel has advantage of high utilization rate of tunnel section. It can accommodate the two-way passage of trains by only one tunnel for each line, which greatly saves the construction cost and makes full use of the limited urban underground space, and has significant economic and social benefits [1][2][3]. With the further improvement of quasirectangular shield construction method, those tunnels would have a wide range of application prospects.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling

et al. 2023

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To use urban underground space more efficiently is a research hotspot of urban underground development. Compared with conventional circular tunnels, quasirectangular tunnels have the characteristics of larger space utilization and higher economic benefits, gradually used in urban rail engineering in recent years. But the ground disturbance induced by the quasirectangular tunneling needs further researches. This paper derives the calculation formula of the additional stress of existing shield tunnel below caused by the quasirectangular shield tunneling by mirror image method and Mindlin solution. The existing shield tunnel is simplified as an elastic foundation short beam connected by tensile springs and shear springs. This paper establishes the energy-deformation coupling equation by principle of minimum potential energy so that the disturbance induced by quasirectangular tunneling to the existing shield tunnel below can be analyzed. The FEM is established with the actual engineering as the background. It is by comparing the numerical simulation results and field monitoring data that the theoretical prediction formula is verified. The research results show that the theoretical calculation results consist highly with numerical simulation results and field monitoring data, verifying practicality of formulas in this paper. Calculation results of shear stagger model are more accurate, which can be also used to analyze the staggered and splayed amount between segments. As the tunnel construction proceeds, uplift deformation, segment stagger, shear force, and segment splay of existing shield tunnel gradually increase, which are symmetrical about the central axis of new tunnel. After the shield machine passes through the central axis of the existing shield tunnel for 20 meters, stable disturbance to the existing shield tunnel occurs. Stagger amount and shear force between segments reach the minimum at the position with maximum uplift deformation of existing shield tunnel and reach the maximum at inflection point of the uplift deformation curve.

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Study on Excavation Sequence of Pilot Tunnels for a Rectangular Tunnel Using Numerical Simulation and Field Monitoring Method

Cited by 35 publications

References 31 publications

Research on Internal Structure and Mechanism of Landslide Based on Hydrogeophysical Investigation (Quan’an Landslide, Southwest China)

Research on Internal Structure and Mechanism of Landslide Based on Hydrogeophysical Investigation (Quan’an Landslide, Southwest China)

Numerical conformal mapping for underground tunnels with arbitrary shapes based on Symm’s method

Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling

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