Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel

This paper studies on a certain highway project which passes through Longmen Shan fault zone, the one triggers 5.12 Wenchuan earthquakes directly. The region where the project resides is characterized by high percentage of soft rock mass, in particular the phyllite. Series of landslide have hitherto happened due to the instability of mountains along the highway which was caused by the great earthquake. Besides, since the phyllite-dominated rock was low-strength and easily soften by water, engineering disasters such as cave-in and large deformation of surrounding rock occurred frequently during the construction of tunnels located along the highway. The existing deformation control criteria fail gradually to fill the requirements of safe tunnelling. The author analyzed monitoring data from different tunnels with different cross-section types and different surrounding rock conditions, referred to relevant norms and eventually proposes new deformation control criteria based on allowable deformation and deformation rate.

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Analysis of Deformation Mechanism and Control Technology of Soft Rock Tunnel with High Geostress

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.794 ◽

2014 ◽

Vol 638-640 ◽

pp. 794-797

Author(s):

Fei Pan ◽

Sheng Guo Cheng

Keyword(s):

Deformation Mechanism ◽

Traffic Engineering ◽

Soft Rock ◽

Control Technology ◽

Engineering Construction ◽

Deformation Control ◽

High Geostress ◽

Rock Tunnels ◽

Rock Tunnel ◽

And Control

With the development of transportation construction, soft rock tunnel with high geostress construction has become a key problem to overcome of traffic engineering construction. In order to explore the deformation mechanism and control technology of soft rock tunnel with high geostress, Xiakou tunnel engineering as an example, the geological characteristics and deformation characteristics of the tunnel were analyzed, to obtain the deformation mechanism of soft rock tunnels with high geostress, and to develop deformation control technology, the results provide a basis and reference for the domestic and foreign the similar engineering construction.

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Support Measures to Prevent the Deformation and Failure of a Carbonaceous Mudstone Tunnel

Advances in Civil Engineering ◽

10.1155/2021/8833502 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Yongdong Wang ◽

Haitao Jiang ◽

Xin Yan ◽

Huiru Liang ◽

Guoan Li ◽

...

Keyword(s):

Soft Rock ◽

Control Measures ◽

Rock Stratum ◽

Deformation And Failure ◽

Pipe System ◽

Deformation Control ◽

Support Measure ◽

Connection System ◽

Prevention And Control Measures ◽

Rock Tunnel

A carbonaceous mudstone tunnel is a type of soft rock tunnel. There is little research on the prevention and control measures for the deformation and failure of carbonaceous mudstone tunnels. In this article, we investigated the construction of the Qiguding carbonaceous mudstone tunnel in Meizhou City, Guangdong Province, China. We monitored and analyzed the deformation and stress characteristics of a section under the original support scheme. The monitoring data showed that this section had large peripheral convergence, vault subsidence, steel arch strain, and concrete strain. The deformations exhibited significant differences in the horizontal and vertical directions, eventually resulting in concrete cracking, steel arch bulging, and distortion in the section. The analysis showed that the primary mechanisms for the failure were the softening characteristics of the carbonaceous mudstone, the plastic rheology, and the shear slip of the rock stratum. Based on a comparative analysis and numerical simulation, we proposed a new support measure called the longitudinal rigid enlarged foundation that consists of a steel arch longitudinal connection system and a locking foot anchor pipe system. Several comparative tests were performed at the tunnel site. The results demonstrated the excellent performance and reliability of the proposed support scheme for the deformation control of the carbonaceous mudstone, providing a reference for similar projects.

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Monitoring and support optimization analysis of surrounding rock pressure and initial supporting stress in deep-buried soft rock tunnel

Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería ◽

10.23967/j.rimni.2021.01.003 ◽

2020 ◽

Vol 36 (4) ◽

Author(s):

Q. Liu ◽

R. Li ◽

W. Tian ◽

Y. Wang ◽

X. Li

Keyword(s):

Rock Pressure ◽

Soft Rock ◽

Northwest China ◽

Surrounding Rock ◽

Steel Frame ◽

Control Effect ◽

Measuring Point ◽

Deformation Control ◽

Surrounding Rock Pressure ◽

Rock Tunnel

Attempting at the problems of surrounding rock pressure and initial supporting stress of deep-buried soft rock tunnel, a soft rock highway tunnel project in Northwest China was monitored on-site for surrounding rock deformation, surrounding rock pressure, initial stress and other items.Discuss the deformation laws and stress characteristics of surrounding rock and steel arch at different construction stages, and compare and analyze the deformation control effect of surrounding rock with different initial lining thickness, different initial elastic modulus and different anchor length through numerical simulation.The results show that the excavation stage of the upper step is a stage where the pressure and deformation of the surrounding rock increase rapidly. The steel arch support is mainly compressed, and the average stress can reach more than 50% of the peak value within 5 days. The stress is mostly higher than the measuring point of the lower step. The initial steel frame support of the upper step and the middle step bears a greater load. The excavation of the upper middle step should be "passed quickly and supported in time", and the construction should adopt The “letting first,then resisting” method appropriately increases the reserved deformation of the surrounding rock to relieve the support stress of the primary steel frame. When the deformation of the surrounding rock and the growth rate of the surrounding rock pressure slow down, the secondary lining can be applied in advance. The research results can provide reference and reference for the design and construction of similar tunnel projects.

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Discussion of Tunnel Displacement Control Reference Group the Relevance of Factors for Earthquake Zone

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.353-356.1446 ◽

2013 ◽

Vol 353-356 ◽

pp. 1446-1450

Author(s):

Yi Zhou ◽

Chuan He ◽

Hai Bin Wu ◽

Jin Hua Xu

Keyword(s):

Reference Group ◽

Soft Rock ◽

Burial Depth ◽

Displacement Control ◽

Factors Affecting ◽

Deformation Control ◽

Construction Methods ◽

Earthquake Zone ◽

Rock Tunnel ◽

Control Criterion

In order to explore the factors affecting the establishment of displacement control criterion for the soft rock tunnel in the earthquake region and then to provide basis for the following establishment of base values, this paper in the context of a highway soft-rock-tunnel passing through the Long-men-shan Fault, summarized the main influencing factors on the basis of the existing deformation control criterion and then proposed the main factors of deformation control criterion suited for the project after combining its own characteristics. The result revealed that: the burial depth of tunnels and the characteristic of the rock masses are critical factors affecting the deformation control criterion of the soft-rock tunnel in earthquake area; the construction methods and the cross-section dimensions are both the important factors for the deformation control criterion.

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Research on Deformation Control Measures of Surrounding Rock in Soft Rock Tunnel

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/636/1/012008 ◽

2021 ◽

Vol 636 ◽

pp. 012008

Author(s):

Junsuo Hao

Keyword(s):

Soft Rock ◽

Surrounding Rock ◽

Control Measures ◽

Deformation Control ◽

Rock Tunnel

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Construction Monitoring and Numerical Simulation of Water-Rich Tuff Soft Rock Tunnel

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/455/1/012163 ◽

2020 ◽

Vol 455 ◽

pp. 012163

Author(s):

Fangliang Chen ◽

Kaihua Zeng ◽

Xuejun Li ◽

Manqing Xu ◽

Hongtao Dai

Keyword(s):

Numerical Simulation ◽

Soft Rock ◽

Construction Monitoring ◽

Rock Tunnel

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Judgement Method for Surrounding Rock Stability of Guanjiao Tunnel Based on Catastrophe Theory

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.2307 ◽

2011 ◽

Vol 90-93 ◽

pp. 2307-2312 ◽

Cited By ~ 2

Author(s):

Wen Jiang Li ◽

Su Min Zhang ◽

Xian Min Han

Keyword(s):

Plastic Strain ◽

Catastrophe Theory ◽

Soft Rock ◽

Surrounding Rock ◽

In Situ Monitoring ◽

Engineering Practice ◽

Stability Of Surrounding Rock ◽

The Stability ◽

Rock Tunnel

The stability judgement of surrounding rock is one of the key jobs in tunnel engineering. Taking the Erlongdong fault bundle section of Guanjiao Tunnel as the background, the stability of surrounding rock during construction of soft rock tunnel was discussed preliminarily. Based on plastic strain catastrophe theory, and combining numerical results and in-situ data, the limit displacements for stability of surrounding rock were analyzed and obtained corresponding to the in-situ monitoring technology. It shows that the limit displacements obtained corresponds to engineering practice primarily. The plastic strain catastrophe theory under unloading condition provides new thought for ground stability of deep soft rock tunnel and can be good guidance and valuable reference to construction decision making and deformation managing of similar tunnels.

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