scholarly journals Research on Mechanical Characteristic of Weak Surrounding Rock Large Span Double and Multi-arch Tunnel Construction

2014 ◽  
Vol 8 (1) ◽  
pp. 373-385 ◽  
Author(s):  
Lu Junfu ◽  
Yu Yu ◽  
Wang Xun
Keyword(s):  
Plastic Zone ◽  
Research Result ◽  
Deformation Characteristic ◽  
Side Wall ◽  
Surrounding Rock ◽  
Large Span ◽  
Radial Depth ◽  
Tunnel Design ◽  
Left And Right ◽  
Weak Surrounding Rock

According to construction scheme of some weak surrounding rock large span double and multi-arch tunnel works, finite element value simulation method is adopted to research weak surrounding rock deformation characteristic, anchor bolt mechanics characteristic, preliminary support and secondary lining structure mechanical characteristics, etc, and the research result shows that: repeatedly disturbance of excavation of middle pilot tunnel and subsequent supporting excavation shall easily reduce surrounding rock strength in the range of middle wall top and middle line of arch top of left and right pilot tunnels, therefore, prior to excavation of middle pilot tunnel, surrounding rock of tunnel top shall be pregrouting reinforced to improve integrated strength of surrounding rock of arch top, max. accumulated settlement displacement of tunnel is 19.45mm, max. horizontal convergence displacement of side wall of left and right tunnel is 9.71mm, max. vertical upheaval displacement of middle wall bottom is 8.82mm, above displacement can all be within controlled range satisfying design requirement; max. plastic zone vertical depth of upper side of left and right tunnel arch top is respectively 1.23m and 2.06m, inverted arch bottom plastic zone vertical depth is 2.74m and 3.37m, radial depth of middle plastic zone of side wall of left and right tunnel is respectively 0.87m and 1.73m, mutual impact range of spatial effect of tunnel face of left and right tunnel is 3 folds tunnel span. This research shall be referred to by similar tunnel design and construction.

scholarly journals Research on Mechanical Characteristic of Weak Surrounding Rock Large Span Double and Multi-Arch Tunnel Construction

2014 ◽  
Vol 8 (1) ◽  
pp. 420-426
Author(s):  
Junfu Lu ◽  
Yu Yu ◽  
Xun Wang
Keyword(s):  
Plastic Zone ◽  
Research Result ◽  
Deformation Characteristic ◽  
Side Wall ◽  
Surrounding Rock ◽  
Large Span ◽  
Radial Depth ◽  
Tunnel Design ◽  
Left And Right ◽  
Weak Surrounding Rock

According to construction scheme of some weak surrounding rock large span double and multi-arch tunnel works, finite element value simulation method is adopted to research weak surrounding rock deformation characteristic, anchor bolt mechanics characteristic, preliminary support and secondary lining structure mechanical characteristics, etc, and the research result shows that: repeatedly disturbance of excavation of middle pilot tunnel and subsequent supporting excavation shall easily reduce surrounding rock strength in the range of middle wall top and middle line of arch top of left and right pilot tunnels, therefore, prior to excavation of middle pilot tunnel, surrounding rock of tunnel top shall be pregrouting reinforced to improve integrated strength of surrounding rock of arch top, max. Accumulated settlement displacement of tunnel is 19.45 mm, max. Horizontal convergence displacement of side wall of left and right tunnel is 9.71 mm, max. Vertical upheaval displacement of middle wall bottom is 8.82 mm, above displacement can all be within controlled range satisfying design requirement; max. plastic zone vertical depth of upper side of left and right tunnel arch top is respectively 1.23 m and 2.06 m, inverted arch bottom plastic zone vertical depth is 2.74 m and 3.37 m, radial depth of middle plastic zone of side wall of left and right tunnel is respectively 0.87 m and 1.73 m, mutual impact range of spatial effect of tunnel face of left and right tunnel is 3 folds tunnel span. This research shall be referred to by similar Tunnel design and construction.

scholarly journals Numerical Study on Soft Coal Pillar Stability in an Island Longwall Panel

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qingyun Xu ◽  
Jian-Biao Bai ◽  
Shuai Yan ◽  
Rui Wang ◽  
Shaoxu Wu
Keyword(s):  
Plastic Zone ◽  
Numerical Study ◽  
Deformation Characteristic ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Pillar Width ◽  
Soft Coal ◽  
Geological Conditions ◽  
Longwall Panel ◽  
Coal Pillars

Roadway support and management of longwall panels in an island soft coal panel are always difficult work. In a test mine, stress distribution, deformation characteristic, and plastic zone distribution around the roadway and coal pillars in the development and mining periods were investigated with respect to the widths of different coal pillars using theoretical and simulation methods. The most reasonable width of coal pillars was comprehensively determined, and the field test was conducted successfully. The results show that a reasonable width of coal pillars is 7.0–8.2 m using the analytical method. The distribution of vertical stress in the coal pillars showed an asymmetric “double-hump” shape, in which the range of abutment pressure was about 26.0–43.0 m, and the roadway should be laid away from stress concentration. When the coal pillar width is 5.0–7.0 m, deformation of the roadway is half that with 8.0–10.0 m coal pillar in the development and mining period. The plastic zone in the surrounding rock firstly decreases and increases with increasing coal pillar width; the smallest range occurs with a coal pillar width of 5.0 m. Finally, a reasonable width for coal pillars in an island panel was determined to be 5.0 m. Industrial practice indicated that a coal pillar width of 5.0 m efficiently controlled deformation of the surrounding rock, which was an important basis for choosing the width of coal pillars around gob-side entries in island longwall panels with similar geological conditions.

Study on Design of Tunnel Section for Danba Diversion Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1732-1735
Author(s):  
Jie Liu ◽  
Liang Tang ◽  
Ya Zuo ◽  
Jin Long Guo
Keyword(s):  
Stability Analysis ◽  
Plastic Zone ◽  
Cross Sections ◽  
Surrounding Rock ◽  
Hydropower Station ◽  
Diversion Tunnel ◽  
Rock Stability ◽  
Tunnel Section ◽  
Tunnel Design ◽  
The Stability

Analyzing and Evaluating the stability of the surrounding rock is an indispensable and important part in the tunnel design. In this paper, the surrounding rock stability of Danba hydropower station diversion tunnel is dealt with, FLAC3Dsoftware is used for stability analysis. Selecting three different cross sections for calculation models, comparing with the displacement and principal stress and the plastic zone which calculated by FLAC3D, we can evaluate their stability and get the best diversion tunnel design.

scholarly journals Evaluation of a tunnel in Yunnan using CRD construction method

2019 ◽  
Vol 136 ◽  
pp. 04020
Author(s):  
Jun Duan ◽  
Canrong Huang ◽  
Xiangyang Cui ◽  
Ke Li ◽  
Hongyan Guo
Keyword(s):  
Plastic Zone ◽  
Side Wall ◽  
Construction Safety ◽  
Construction Method ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Monitoring Point ◽  
The Right ◽  
Tunnel Monitoring

According to the surrounding rock conditions of Re Shuitang Tunnel NO.2, it is analyzed whether the CRD method is suitable for such surrounding rock conditions. By comparing and analyzing the distribution of plastic zone of surrounding rock during construction and the displacement deformation of tunnel monitoring point, the tunnel is constructed. The plastic zone of the middle arch and the arch is obviously changed, and should be reinforced. The settlement of the right vault and the side wall is larger than the left side, which is about 19.8% and 21.9%. According to the analysis results, the vault should be reinforced in advance during tunnel construction to prevent collapse and ensure construction safety, and provide reference for future construction.

Stability Analysis of an Underground Pumping Station Group of China

2017 ◽  
Vol 865 ◽  
pp. 403-408 ◽  
Author(s):  
De Ping Chen ◽  
Li Peng Liu ◽  
Li Xin Zhao ◽  
Yang Zhang
Keyword(s):  
Plastic Zone ◽  
Side Wall ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Main Concern ◽  
Maximum Displacement ◽  
Pumping Station ◽  
Underground Caverns ◽  
Large Underground Cavern ◽  
Station Group

The stress and strain of surrounding rock and the development of plastic zone in the process of excavation of large underground cavern group have been the main concern of the design unit. The numerical simulation software is used to analyze the stability of caverns of an underground pumping station. The stress and displacement of the surrounding rock and the development of the plastic zone in the process of excavation are analyzed in detail. The results show that the tensile stress is easily generated in the side wall, and the maximum value can reach 4 M Pa. Correspondingly, the maximum displacement of the side wall part can reach 4 cm. The plastic zone is mainly concentrated in the surrounding rock near the side wall, the thickness can reach about 9 m. In general, the excavation of underground caverns is basically stable.

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 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.

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