scholarly journals Study on the supporting time of the secondary lining of the highway tunnel with weak surrounding rock

2021 ◽  
Vol 643 ◽  
pp. 012042
Author(s):  
Jiaqing Feng ◽  
Xiaoming Wang ◽  
Yongxing Zhou ◽  
Guofeng Liu ◽  
Kaide Liu
Keyword(s):  
Surrounding Rock ◽  
Highway Tunnel ◽  
Secondary Lining ◽  
Weak Surrounding Rock

scholarly journals Study on construction mechanics behavior of weak surrounding rock with four-lane highway tunnel

2018 ◽  
Author(s):  
Fujin Hou ◽  
Shucai Li ◽  
Xinzhi Li ◽  
Wenjiang Li ◽  
Qing Jiang ◽  
...  
Keyword(s):  
Surrounding Rock ◽  
Highway Tunnel ◽  
Construction Mechanics ◽  
Weak Surrounding Rock

scholarly journals New Construction Technology of a Shallow Tunnel in Boulder-Cobble Mixed Grounds

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Tong Liu ◽  
Yujian Zhong ◽  
Zhihua Feng ◽  
Wei Xu ◽  
Feiting Song ◽  
...  
Keyword(s):  
Surrounding Rock ◽  
Construction Technology ◽  
Construction Process ◽  
Tunnel Excavation ◽  
Supporting System ◽  
Highway Tunnel ◽  
Bulk Medium ◽  
New Construction ◽  
Secondary Lining ◽  
Design And Construction

As a typical granular bulk medium, problems are common in boulder-cobble mixed grounds, such as easy collapse and instability and difficult effective support for large-section tunnel excavation. Tunnels constructed in BCM grounds are rare still, and there is a big gap between the design and construction of tunnels. Based on the Nianggaicun highway tunnel crossing the BCM grounds, the construction technology of tunnel in BCM grounds is studied by means of literature investigation and field survey. Here are the main conclusions: the overall deformation of surrounding rock is quite small; the pressure distribution of surrounding rock is small and loose pressure is dominant, and the safety reserve of secondary lining is large. The deformation process of surrounding rock concentrates on the construction stage. During the construction process, there are many problems, such as serious overexcavation, difficulty of bolt penetration, and continuous rock fall. In this paper, a three-bench complementary cyclic excavation method is proposed, which replaces the original CD and CRD methods. Meanwhile, the supporting system is optimized. The results show that the disturbance of surrounding rock is reduced, while the safety of construction process and the reliability of structure are increased. The new excavation method and optimized supporting system are expected to fill the gap between design and construction of tunnel in BCM grounds and provide reference for construction of such tunnels in the future.

Field Monitoring and Numerical Simulation Study on Mechanical Characteristics of Extra-Long Highway Tunnel

2012 ◽  
Vol 170-173 ◽  
pp. 1450-1454
Author(s):  
Xun Li ◽  
Chuan He ◽  
Guo Wen Xu
Keyword(s):  
Numerical Simulation ◽  
Mechanical Characteristics ◽  
Safety Monitoring ◽  
Surrounding Rock ◽  
Tunnel Face ◽  
Highway Tunnel ◽  
Surrounding Rock Pressure ◽  
Secondary Lining ◽  
Monitoring And Measurement ◽  
Monitoring Information

Taking Motianling tunnel in Chongqing as an engineering background, the monitoring and measurement scheme is proposed for the extra-long tunnel under complex condition, and the field data and the numerical simulation results is analyzed. The results indicates that, the selected cross-section reflect overall state of the Motianling tunnel, and the structure safety monitoring during operation is considered; by tunnel internal and external observation, it is found that the tunnel face in F22 fault zone may not stay stability, because the monitoring information receive feedback timely, and the supporting measures is proper, the surrounding rock stay stability when excavating; for the typical section, the surrounding rock contact pressure is greater than interlayer pressure, primary lining sustains most of the load ,and the secondary lining plays an assistant role as safety reservation; the maximum of anchor axial force and surrounding rock pressure occur at tunnel crown. By monitoring and numerical simulation, the dynamic excavation and design is realized, the Motianling tunnel is achieved safely and successfully at last.

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

scholarly journals Deformation Characteristics of the Surrounding Rock of a Six-Lane Multiarch Tunnel under Different Excavation Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lina Luo ◽  
Gang Lei ◽  
Haibo Hu
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Surrounding Rock ◽  
Displacement Rate ◽  
Construction Technology ◽  
Deformation Characteristics ◽  
Highway Traffic ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Secondary Lining

Highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions. Therefore, it is necessary to explore the deformation characteristics of the surrounding rock of a six-lane multiarch tunnel under different excavation conditions. Using the three-dimensional indoor model test and finite element analysis, this paper studies the dynamic mechanical behavior of a six-lane construction, reveals the whole process of the surrounding rock deformation process of class II surrounding rock under different excavation conditions, and puts forward the best construction and excavation method. The results show that the maximum displacement rate of excavation scheme III is the largest, and the maximum displacement rate of excavation scheme I is basically the same as that of excavation scheme II. Therefore, in terms of controlling the displacement rate of the surrounding rock, the effect of excavation scheme I is basically the same as that of excavation scheme II, while that of excavation scheme III is poor. In terms of construction technology, scheme II is simpler than scheme I and can ensure the integrity of the secondary lining. Therefore, in class II surrounding rock of the supporting project, it is recommended to adopt scheme II for construction.

Mutual influence of long-span urban highway tunnel and rail transit construction

2021 ◽  
pp. 1-15
Author(s):  
Honglin Yu ◽  
Shiyang Liu ◽  
Chun Zheng ◽  
Yun Li ◽  
Jie Liu
Keyword(s):  
Mutual Influence ◽  
Vertical Displacement ◽  
Relative Displacement ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Railway Line ◽  
Long Span ◽  
Highway Tunnel ◽  
Urban Rail ◽  
Secondary Lining

In order to analyze the mutual influence between the long-span highway tunnel and urban rail transit tunnel that is constructed at proximity, this paper established 3D finite element models based on Chongqing Zengjiayan Tunnel and the Metro Railway Line 9 and Line 10 projects to calculate and analyze the secondary lining stress, distribution and change law of deformation of Zengjiayan Tunnel and the Metro Railway Line Tunnel. The results show that: (1) The main risk of the Zengjiayan Tunnel is that the tunnel body might displace in the excavation and the surrounding rock stress could possibly change. The forces undertaken by the main structure of the cross-section are calculated and analyzed based on the shallow buried tunnel. Accordingly, the horizontal and vertical displacement limit and relative displacement meet the relevant specification; (2) Zengjiayan Tunnel over the lobby of Liyuchi Station, a transitional station of Line 9 and Line 10. The main risk is the displacement of the transitional channel in the excavation and changes in the stress on surrounding rocks, but the risk of self-structure excavation and support is under control.

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