Structure Optimization for the Support System in Soft Rock Tunnel Based on Numerical Analysis and Field Monitoring

Gao, Shiming; Chen, Jianping; Zuo, Changqun; Wei, Wang; Sun, Yang

doi:10.1007/s10706-016-0029-3

Cited by 19 publications

(12 citation statements)

References 11 publications

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“…rough on-site monitoring and numerical simulation analysis, Gao et al [26] found that the support structure of soft rock tunnels can be optimized by weakening the anchor while enhancing the initial support stiffness and strength, thereby saving costs. Sun et al [27] studied the system of negative Poisson's ratio (NPR) constant resistance and large deformation anchor cable support.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Stress and Deformation Characteristics of Deep‐Buried Phyllite Tunnel Structure under Different Cross‐Section Forms and Initial Support Parameters

Yang

Cai

et al. 2021

Advances in Civil Engineering

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Deep-buried soft rock tunnels exhibit low strength and easy deformation under the influence of high ground stress. The surrounding rock of the soft rock tunnel may undergo large deformation during the construction process, thereby causing engineering problems such as the collapse of the vault, bottom heave, and damage to the supporting structure. The Chengwu Expressway Tunnel II, considered in this study, is a phyllite tunnel, with weak surrounding rock and poor water stability. Under the original design conditions, the supporting structure exhibits stress concentration and large deformation. To address these issues, three schemes involving the use of the double-layer steel arch to support, weakening of the steel arch close to the excavation surface, and weakening of the steel arch away from the excavation surface to support were proposed. Using these schemes, the inverted radius was varied to explore its influence on different support schemes. For simulation, the values of the inverted radius selected were as follows: 1300 cm, 1000 cm, and 700 cm. The proposed support plan was simulated using FLAC3D, and the changes in the pressure between the initial support and surrounding rock, the settling of the vault, and the surrounding convergence were investigated. The numerical simulation results of monitoring the surrounding rock deformation show that the double-layer steel arch can effectively reduce the large deformation of the soft rock well. When the stiffness of one of the steel arches was weakened, the support’s ability to control the deformation was weakened; however, it still showed reliable performance in controlling deformation. However, changing the radius of the invert had an insignificant effect on the deformation and force of the supporting structure.

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Section: Introductionmentioning

confidence: 99%

Analysis of Stress and Deformation Characteristics of Deep‐Buried Phyllite Tunnel Structure under Different Cross‐Section Forms and Initial Support Parameters

Yang

Cai

et al. 2021

Advances in Civil Engineering

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“…tunnels. At present, there are neither mature experience nor specifications for reference [1][2][3][4][5]. During the construction of large cross-section tunnel, excavation and support structure installation are often carried out continuously.…”

Section: Introductionmentioning

confidence: 99%

Analysis for bearing performance and construction mechanical behavior of supporting structure for the large cross-section tunnel by half bench CD method

Zhao

2021

PLoS ONE

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Based on the engineering practice of large cross-section highway tunnel, this paper reveals the space-time coordinated evolution law of the construction mechanical characteristics and deformation distribution of the support structure in the construction by half bench CD method through field test. At the same time, the mechanical response calculation model of the supporting structure in the partial excavation is constructed, and the mechanical characteristics of the support structure in the partial excavation process are analyzed by above mechanical calculation model. Then, the mechanical and deformation distribution of the feet-reinforcement bolt in the steel frame—foot-reinforcement bolt combined support system is analyzed under different levels of surrounding rock load and different structural parameters of the feet-reinforcement bolt. The research results show that: (1) The internal force of the supporting structure changes most obviously during the excavation of Part Ⅰ, Part Ⅱ and Part Ⅲ, and the internal force of the support structure gradually tends to be stable after a slight increase in the excavation of Part Ⅳ and Part Ⅴ; (2) The horizontal deformation and vertical deformation of the support structure mainly occur in the excavation process of Part Ⅰ, Part Ⅱ and Part Ⅲ, and the excavation of Part Ⅳ and Ⅴ has little effect on the deformation response of the structure. The vertical displacement of the supporting structure is larger than the horizontal displacement, and the dynamic response of the temporary diaphragm structure during tunnel excavation is shrinkage-expansion-shrinkage-expansion; (3) The bending strain of each measuring point decreases with the increase of the distance from the loading point, and the bending strain of section 1 and section 2 is much larger than that of the other three sections; (4) With the increase of the angle, the section position with strain close to 0 gradually moves to the deeper position of the bolt, and the axial strain of each section on the bolt gradually changes from positive strain to negative strain.

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“…Many scholars have studied the characteristics of tunnel support structure and the mechanical laws in the construction process and optimized the design parameters of the support structure [20][21][22][23]. However, these research studies are only limited to the two-lane tunnel, and these parameters are no longer applicable for the superlarge-span tunnel because the stability of the tunnel structure decreases with the excavation span increasing.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Deformation Characteristics and Optimization of Support Parameters for Superlarge‐Span Tunnel: A Case Study from Laohushan Tunnel

Luo

Chen

Shi

et al. 2020

Advances in Civil Engineering

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In the new construction or reconstruction of expressway projects, the number of highway twin tunnels with eight lanes is increasing. However, there are no corresponding design support parameters and measures in the current technical specifications for tunnel design and construction in China. In Laohushan superlarge-span highway tunnel with single hole and four lanes, the deformation behavior and mechanical characteristics of support structures are measured and analyzed. The monitoring results indicated that the deformation of tunnel structure mainly experienced three stages: rapid deformation, slow deformation, and stable deformation, and finally reached a relatively stable state; the structure stress of primary support and secondary lining increases sharply at first and then tends to be stable gradually with the gradual construction of each excavation part in the tunnel; the stress of each measuring point at the steel rib is less than the yield limit of steel rib (235 MPa), and the support structure is safe and stable in the process of tunnel construction. Then, the structure safety of primary support under different support parameters is simulated and calculated by numerical simulation with Grade IV rock mass, and the reasonable support parameters for Laohushan highway tunnel are studied considering the structural safety and engineering economy. It is suggested to use the H175-type steel sets with a distance of 80 cm and C25 shotcrete with a thickness of 26 cm. The results could provide reference for similar tunnel projects and provide a basis for the design specification and construction standards for superlarge-span tunnels.

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Structure Optimization for the Support System in Soft Rock Tunnel Based on Numerical Analysis and Field Monitoring

Cited by 19 publications

References 11 publications

Analysis of Stress and Deformation Characteristics of Deep‐Buried Phyllite Tunnel Structure under Different Cross‐Section Forms and Initial Support Parameters

Analysis of Stress and Deformation Characteristics of Deep‐Buried Phyllite Tunnel Structure under Different Cross‐Section Forms and Initial Support Parameters

Analysis for bearing performance and construction mechanical behavior of supporting structure for the large cross-section tunnel by half bench CD method

Mechanical and Deformation Characteristics and Optimization of Support Parameters for Superlarge‐Span Tunnel: A Case Study from Laohushan Tunnel

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