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 Stability and Plastic Zone Distribution of Tunnel with Thin Carbonaceous Slate at Different Dip Angles

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jin Zhang ◽  
Chuanhao Xi ◽  
Qian Zhang ◽  
Mengxue Wang
Keyword(s):  
Tensile Strength ◽  
Plastic Zone ◽  
Field Measurement ◽  
Joint Angle ◽  
Rock Joint ◽  
Great Influence ◽  
Surrounding Rock ◽  
Test Field ◽  
Maximum Displacement ◽  
Dip Angle

Carbonaceous slate is heterogeneous and anisotropic, which has a great influence on the stability of tunnel. In this paper, by means of laboratory test, field measurement, and numerical simulation, the surrounding rock stability and plastic zone distribution characteristics of the carbonaceous slate tunnel at different intersection angles are analyzed. First, combined with the Haibaluo tunnel project, Brazilian splitting and uniaxial compression tests of jointed carbonaceous slate are performed. The test results show that the tensile strength of carbonaceous slate is related to joint dip angle. When the joint angle is 0°, the tensile strength is the largest and decreases with the increase of the joint angle. The uniaxial strength of rock decreases first and then increases. Based on the discrete fracture network (DFN) technology, a calculation model is established. The calculation results show that the maximum displacement is 0.45 m, when the dip angle of the surrounding rock joint is 45°. The field measurement also shows that the dip angle of the surrounding rock joint has an important influence on the distribution of the plastic zone. When the joint dip angle is 45°, the plastic zone develops most strongly.

scholarly journals Deformation and Failure Mechanism of Surrounding Rock in Mining-Influenced Roadway and the Control Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jicheng Feng ◽  
Shuaifeng Yin ◽  
Zhiheng Cheng ◽  
Jianjun Shi ◽  
Haoyu Shi ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Failure Mechanism ◽  
Principal Stress ◽  
Pressure Ratio ◽  
Confining Pressure ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Morphologic Change ◽  
Deformation And Failure ◽  
Implicit Equation

Aiming at the problem of surrounding rock deformation and failure of mining roadway and its control, a mechanical model of the circular roadway under the mining environment is established, and the implicit equation of the plastic zone boundary is derived. By analyzing the morphologic evolution law of the surrounding rock plastic zone in the mining roadway, the key factors affecting the morphologic change of the plastic zone are obtained, that is, the magnitude and direction of principal stress. The influence law of the magnitude and direction of principal stress on the plastic zone of the mining roadway is analyzed by using numerical simulation software, and the deformation and failure mechanism of surrounding rock of the mining roadway is revealed. The results showed that the size and morphology of the plastic zone were closely related to the confining pressure ratio (η). Taking the boundary of η valuing 1, the larger or smaller η value was, the more serious the deformation and failure of surrounding rock would be; the morphology of the plastic zone changed with the deflection of the principal stress, with the location of the maximum plastic zone influenced by the principal stress direction. For the surrounding rock control in the mining-influenced roadway, it is advised to take the following methods: firstly, it is necessary to consider how to reduce or remove the influence of mining on surrounding rock, improve the stress environment of surrounding rock, and reduce the failure depth of the plastic zone, so as to better maintain the roadway. Secondly, in view of the deformation and failure characteristics of the mining roadway, the fractional support method of “yielding first and then resisting” should be adopted, which applies the cable supplement support after mining instead of the one-off high-strength support during roadway excavation, so as to control the malignant expansion of the surrounding rock plastic zone and prevent roof falling accidents.

scholarly journals Optimal Support Solution for a Soft Rock Roadway Based on the Drucker–Prager Yield Criteria

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 1
Author(s):  
Minghui Ma ◽  
Qifeng Guo ◽  
Jiliang Pan ◽  
Chi Ma ◽  
Meifeng Cai
Keyword(s):  
Internal Friction ◽  
Plastic Zone ◽  
Soft Rock ◽  
Friction Angle ◽  
Intermediate Principal Stress ◽  
Surrounding Rock ◽  
Term Strength ◽  
Maximum Displacement ◽  
Calculation Results

Through theoretical calculation, the stress and deformation of surrounding rock can be analyzed, providing guidance for the support design and optimization of soft rock roadways. In this paper, theoretical solutions for both the optimal support pressure and the allowable maximum displacement of surrounding rock are derived from the Drucker–Prager (DP) yield criteria and the steady creep criterion expressed by the third invariant of deviator stress. The DP criterion with different parameters is compared and analyzed with an engineering example. Then, based on the calculation results the effects of long-term strength, cohesion, and internal friction angle of soft rock on the maximum plastic zone radius and allowable maximum displacement of roadway are discussed. The results show that the optimal support solution of soft rock roadways based on the DP criteria can not only reasonably reflect the intermediate principal stress but can also be used to compare and discuss the influence of different DP criteria on the calculation results. The higher the long-term strength of the rock surrounding a roadway is, the smaller the optimal support force is and the larger the allowable maximum displacement is. When the calculated long-term strength of soft rock can ensure that the deformation of the roadway does not exceed the allowable maximum displacement, the roadway can maintain long-term stability without support. With an increase in the cohesion or internal friction angle of soft rock, the radius of the plastic zone decreases gradually and the allowable maximum displacement is reduced by degrees. The use of grouting and other means to improve the strength of surrounding rock can effectively reduce the roadway deformation and save support costs. This new theoretical solution can consider different intermediate principal stress effects and different DP strength criteria, enabling the parameters to become easier to determine. It has a wider range of applications, and the calculation results better demonstrate the strength potential of the surrounding rock.

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.

The Numerical Study of the Stability of Roadway Seeping in the Roof

2012 ◽  
Vol 178-181 ◽  
pp. 1293-1296
Author(s):  
Feng Zhen Liu ◽  
Wei Guo Qiao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Plastic Zone ◽  
Numerical Study ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Key Factors ◽  
Roadway Stability ◽  
The Stability ◽  
Roadway Deformation

Seepage in the roof is one of main reasons resulting softening rock and roadway deformation, in order to make sure about the influence of seepage on the roadway stability, we established corresponding models by using numerical simulation software, and analyzed the stress distribution, the deformation of surrounding rock, and the distribution range and shape of the plastic zone, the results show that water is one of the key factors to influence the stability of roadway, seepage makes the strength of surrounding rock sharply reduce, and the roof, two ribs and floor appear serious deformation.

The Nonlinear Analysis of Sensitivity of the Plastic Zone of Surrounding Rock in Underground Caverns

2014 ◽  
Vol 926-930 ◽  
pp. 687-692 ◽  
Author(s):  
Zhi Fang Tian ◽  
Zhi Min Su ◽  
Nian Hong Jiang ◽  
Xue Lu ◽  
Jian Bing Zhu
Keyword(s):  
Analytical Solution ◽  
Plastic Zone ◽  
Friction Angle ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Water Tunnel ◽  
Circular Tunnel ◽  
Finite Element Software ◽  
Underground Caverns ◽  
The Relationship

As the depth and the length of the various underground cavern is increasing, the stability analysis of surrounding rock is very important. This paper first gives the analytical solution equation of the circular tunnel. About the city-gate water tunnel with no analytical solution, it can be solved by numerical method, which is based on the large finite element software ANSYS. The form of a calculation model for conveyance city-gate water tunnel was established. With the D - P criterion, it is nonlinear calculated for the computation of water conveyance tunnel. Then it is obtained that the stress characteristic and development of plastic zone characteristics of the surrounding rock of city-gate tunnel. It also gives the relationship between the development of plastic zone, plastic strain and coefficient of horizontal pressure, the internal friction angle. The last, it is analyzed the relationship between the different parameters and the plastic zone development of different parts of tunnel cavern. This result can provide technical reference for design and the tunnel construction.

Application of Stereographic Projection in the Search of Key Block of Surrounding Rock Mass for Underground Powerhouse

2010 ◽  
Vol 44-47 ◽  
pp. 1189-1192
Author(s):  
Zhong Chang Wang
Keyword(s):  
Rock Mass ◽  
Stereographic Projection ◽  
Side Wall ◽  
Surrounding Rock ◽  
Main Role ◽  
Measuring Point ◽  
Underground Powerhouse ◽  
Underground Caverns ◽  
Key Block ◽  
The Stability

The rose diagram of joint is generalized by grouping the attitude of disclosed discontinuous faces in detecting cavern and measuring point coordinate. The search of movable and key blocks of surrounding rock mass for underground powerhouse is implemented, the combinations of discontinuous faces and sliding faces, the location and the parameter of stability of movable and key blocks are obtained by used of the method of stereographic projection and vector analysis of the block theory. It is shown that the numbers of movable and key blocks in the location of downriver right side wall and vault are larger than those in other location owing to numerous discontinuous faces, and the faults of F34 and F33 play a main role in the stability of movable and key blocks. The guidance for excavation and reinforce of underground caverns is provided.

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 Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

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