scholarly journals Analysis of Plastic Zone and Pressure Variance Features of Surrounding Rock of High-Altitude Macker Tunnel: A Case Study in Jiangluling Macker Tunnel in Qinghai

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaojun Ma ◽  
Hongyan Guo ◽  
Juyi Hu ◽  
Shuang Cai ◽  
Liang Cheng ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Structural Design ◽  
Measurement Data ◽  
Surrounding Rock ◽  
Analysis Method ◽  
Support Structure ◽  
Tunnel Support ◽  
Influence Radius ◽  
Design Of Tunnel Support

Due to the special mechanical properties of macker rock, problems may be caused easily if the pressure of the surrounding rock calculated from the standard empirical equation is used in the structural design of tunnel support, such as obviously insufficient bearing capacity of the support structure, large deformation, and collapse. Taking the Jiangluling Macker Tunnel in Gonghe-Yushu Highway as an example, the distribution pattern of plastic zone of the surrounding rock and the calculation method and reasonable values of pressure of the surrounding rock are studied in this paper, by means of theoretical analysis, numerical computation, and field measurement data. The results show that the elastic-plastic analysis method is suitable for the pressure of the surrounding rock of macker tunnel. The influence radius of the plastic zone of the surrounding rock can be 32 m, and the lateral pressure of the surrounding rock of the tunnel is equivalent to the vertical pressure. In the absence of test conditions and measured data, the pressure of the surrounding rock can be approximately 0.83 MPa for the purpose of design of tunnel support structure. This conclusion provides technical support for projects in similar conditions.

Grey Correlation Analysis on the Sensitive Factors of Plastic Zone Extension of Surrounding Rock

2013 ◽  
Vol 438-439 ◽  
pp. 1210-1216
Author(s):  
Xuan Rong Zheng
Keyword(s):  
Correlation Analysis ◽  
Plastic Zone ◽  
Deformation Modulus ◽  
Friction Angle ◽  
Surrounding Rock ◽  
Unit Weight ◽  
Analysis Method ◽  
Grey Correlation ◽  
Grey Correlation Analysis ◽  
Ground Stress

As lack of explicit analysis method on the sequence of many factors influencing the plastic zone extension of surrounding rock, the grey correlation analysis method is adopted to study the relationship between the plastic zone extension radius Rp and the six factors such as cohesive c, internal friction angle φ, deformation modulus E, unit weight γ, initial ground stress σ and the radius of chamber r. By dealing with dimensionless, the corresponding sequences composed with the sensitive factors as sub-sequence and the plastic zone extension radius as mother sequence are obtained. The gray correlation analysis model of sensitive factors which evaluates the results with grey correlation degree is built by the methods of dimensionless and extreme difference variation. Then, an engineering example is analyzed with grey correlation. Based on the analysis results, the sorting of sensitive factors is φ > σ > c > r > E > γ. It implies that the influences of internal friction angle φ and initial ground stress σ are the most prominent, and the sensitivities of deformation modulus E and unit weight γ are lowest. These are in good agreement with the analytical formula of classical theory, and can be used in guiding the further optimization and improvement of the analytical expression of the plastic zone extension radius Rp of surrounding rock.

Study on Structural Design of Loess Tunnel with Large Transection and its Construction Method in the Expressway from Datong to Hunyuan

2012 ◽  
Vol 170-173 ◽  
pp. 1712-1715 ◽  
Author(s):  
Xiao Jun Zhou ◽  
Zhi Yuan Wang ◽  
Yin Hua Fan
Keyword(s):  
Structural Design ◽  
Construction Method ◽  
Surrounding Rock ◽  
Great Success ◽  
Hydrogeological Condition ◽  
Running Speed ◽  
Tunnel Support ◽  
New Construction ◽  
Motorized Vehicles

According to the engineering geological and hydrogeological condition of loess tunnel with large transection in the expressway from Datong to Hunyuan, and on the basis of the planned running speed of motorized vehicles in the loess tunnel, the excogitative parameters of tunnel support for relevant surrounding rock and its driving method have been put forth in this paper. The application of the presented new construction method for expressway loess tunnel has accomplished a great success.

scholarly journals Research on Temperature Field of Support Structure for Independent LNG Tank

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Shifeng Ding ◽  
Li Zhou ◽  
Yingjie Gu ◽  
Yajun Zhou
Keyword(s):  
Temperature Field ◽  
Structural Design ◽  
Cylindrical Tank ◽  
Support Structure ◽  
Thermal Boundary Conditions ◽  
Hull Structure ◽  
The Common ◽  
Nature Gas ◽  
Lng Tank

The independent LNG (Liquified Nature Gas) containment is widely used for small or medium-sized LNG carrier and ship using LNG as fuels. The common tank pattern includes single-spherical-cylindrical tank and double-spherical-cylindrical tank, which is the key to design the hull structure and its support. The support is designed to connect the hull structure and LNG tank. Its main functions are heat transferring and force loading. This paper focus on the temperature field distribution of hull and its support structure. The thermal boundary conditions are simulated according to the heat transfer action, such as thermal convection, heat conduction and thermal radiation. The method on how to carry out thermal analysis is presented for an independent LNG containment. The case study is carried out with two typical independent LNG tanks. One is a tank with double spherical cylindrical in the LNG carrier, and the other is a tank with single spherical cylindrical on the deck of the ship using LNG as fuels. The result shows the method presented in this paper is a good reference for the structural design with independent LNG containment.

scholarly journals The Plastic Zone of Tunnel Surrounding Rock under Unequal Stress in Two Directions Based on the Unified Strength Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zongshan Zou ◽  
Jun Yang ◽  
Zhongming Wang ◽  
Hongyan Liu
Keyword(s):  
Plastic Zone ◽  
Principal Stress ◽  
Interaction Mechanism ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Surrounding Rock ◽  
Elastic Displacement ◽  
Strength Theory ◽  
Support Structure ◽  
Unified Strength Theory

For the deficiencies that the existing calculation theory for the Plastic Zone of Tunnel Surrounding Rock (PZTSR) does not consider the effect of the intermediate principal stress σ2 and interaction between the surrounding rock and support structure on the PZTSR under unequal stress, the Unified Strength Theory (UST) for the rock is adopted to replace the often used Mohr-Coulomb (M-C) strength criterion to consider the effect of σ2 on the PZTSR. Meanwhile, the interaction mechanism between the surrounding rock and support structure is also considered in the proposed model. Finally, the effect of the initial elastic displacement of the surrounding rock, stiffness of the support structure, and the coefficient b of the intermediate principal stress on the plastic zone is discussed. The results show that the PZTSR will increase nonlinearly with increasing the initial elastic displacement of the surrounding rock, and when it increases to a certain value, its increase extent will be much obvious. With increasing the stiffness of the support structure, the PZTSR will gradually decrease nonlinearly, but the decrease extent is not very much. With increasing b, the PZTSR will decrease; namely, σ2 can improve the stress condition of the surrounding rock and reduce the PZTSR.

scholarly journals Mechanism and Procedure of Repeated Borehole Drilling Using Wall Protection and a Soft Structure to Prevent Rockburst: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yongliang He ◽  
Mingshi Gao ◽  
Xu Dong ◽  
Xin Yu
Keyword(s):  
Energy Absorption ◽  
Control Method ◽  
Stability Control ◽  
Surrounding Rock ◽  
Support Structure ◽  
Geological Conditions ◽  
Borehole Drilling ◽  
The Stability ◽  
Mine Roadways

With the increasing mining depth of coal mines, the occurrence of rockburst, especially in mine roadways, is becoming critical as a severe dynamic disaster. This paper explores the stability control of deep mine roadways and solves the contradiction between the support and pressure relief of roadways by studying the use of an internal steel pipe for wall protection and a soft structure for energy absorption during repeated borehole drilling. Numerical simulations are performed to examine the effects of active support technology on the support structure during repeated drilling. Internal steel pipes can effectively prevent the support structure from being damaged. When the soft structure cracks, the energy transmitted from the rockburst to the roadway is significantly reduced. According to the deformation and failure characteristics of the surrounding rock of the 21170 roadway, the combination of anchor active support, hydraulic lifting shed support, and soft structure energy absorption is proposed. An engineering case study shows that the support method can effectively maintain the stability of the surrounding rock and ensure the safe mining of the working face. The proposed control method can provide reference for the prevention and control of rockburst in mine roadways under similar geological conditions.

scholarly journals Mechanical Analysis of the Circular Tunnel considering the Interaction between the Ground Response Curve and Support Response Curve

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Tianming Su ◽  
Hanyu Peng ◽  
Hongyan Liu
Keyword(s):  
Plastic Zone ◽  
Radial Displacement ◽  
Response Curve ◽  
Mechanical Analysis ◽  
Surrounding Rock ◽  
Elastic Displacement ◽  
Circular Tunnel ◽  
Ground Response ◽  
Support Structure ◽  
Zone Radius

The viewpoint that the ground initial elastic displacement and the interaction between the ground response curve (GRC) and support response curve (SRC) in the surrounding rock should be considered at the same time in the mechanical analysis of the circular tunnel is proposed, and its solution method is also established. Meanwhile, in order to consider the effect of the intermediate principle stress, Drucker-Prager criterion is introduced to describe the yield property of the surrounding rock. The calculation example indicates that the final radial displacement of the tunnel circumference will increase when the ground initial elastic displacement in the surrounding rock is considered before the support structure is applied, which indicates that it is necessary to consider the ground initial elastic displacement in the surrounding rock before the support structure is applied. With increasing the support resistance force and the initial field stress, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference will decrease and increase, respectively, while with increasing the rock internal friction angle and cohesion, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference both decrease. Meanwhile, with the stress Lode parameter increasing from −1 to 1, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference both greatly decrease and then slightly increase. It indicates that the intermediate principle stress has some effect on the calculation results.

scholarly journals Failure Mechanism for Surrounding Rock of Deep Circular Roadway in Coal Mine Based on Mining-Induced Plastic Zone

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yue Yuan ◽  
Weijun Wang ◽  
Shuqing Li ◽  
Yongjian Zhu
Keyword(s):  
Plastic Zone ◽  
Failure Mechanism ◽  
Coal Mine ◽  
Surrounding Rock ◽  
Deformation And Failure ◽  
Uniformity Coefficient ◽  
Shape Coefficient ◽  
The Stability ◽  
The Relationship

In order to reveal the failure mechanism of the deep roadway under mining-induced pressure in coal mine, the boundary equations for the plastic zone around the deep roadway were deduced, and then the evolution laws for morphology of the plastic zone and the relationship between the morphological indexes and the stability of surrounding rock were discussed. The results show that, for the deep roadway, the effect of mining on the plastic zone is more sensitive than that on the shallow one. Even if the changes of mining influence are small, they may also cause extremely serious plastic failure of surrounding rock masses, leading to the sudden instability of the roadway. When the plastic wings of the plastic zone are approximately perpendicular to the roof, floor, or sidewall, the large deformation and failure of the deep roadway are very likely to occur. Compared with the index of the uniformity coefficient, the irregular shape coefficient can be used to better characterize the differences in the plastic zone morphology. Finally, a case study was provided to apply the principles for the formation and extension of a butterfly-shaped plastic zone.

The Real-Time Strain Monitoring of Tunnel Supporting Structure and Nonlinear Regression Analysis

2013 ◽  
Vol 718-720 ◽  
pp. 837-841 ◽  
Author(s):  
Bi He ◽  
Bin Wang ◽  
Chuan Li ◽  
Tong Yao Yang ◽  
Zhou Chun Cai ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Real Time ◽  
Nonlinear Regression ◽  
Measurement Data ◽  
Surrounding Rock ◽  
Analysis Method ◽  
Nonlinear Regression Analysis ◽  
Monitoring Point ◽  
The Real ◽  
Supporting Structure

Concrete embedded fiber Bragg grating strain sensors are used to monitor real-time strain of each section in the tunnel surrounding rock supporting structure, and the nonlinear regression analysis method is adopted to analysis the real-time measurement data. By using nonlinear regression analysis method, the strain development status of surrounding rock supporting structure can be grasped timely and the variation trend of the strain value of monitoring point can be predicted, which can provides foundations for judging the stability of tunnel supporting structure.

Blockchain in Supply Chain: Case Study of Lottemart Ciputat

2019 ◽  
Vol 5 (1) ◽  
pp. 38-49 ◽  
Author(s):  
B. K. Handoyo ◽  
M. R. Mashudi ◽  
H. P. Ipung
Keyword(s):  
Decision Making ◽  
Supply Chain ◽  
Supply Chain Management ◽  
Information Asymmetry ◽  
New Technology ◽  
Business Case ◽  
Analysis Method ◽  
Chain Management ◽  
Production Processes

Current supply chain methods are having difficulties in resolving problems arising from the lack of trust in supply chains. The root reason lies in two challenges brought to the traditional mechanism: self-interests of supply chain members and information asymmetry in production processes. Blockchain is a promising technology to address these problems. The key objective of this paper is to present qualitative analysis for blockchain in supply chain as the decision-making framework to implement this new technology. The analysis method used Val IT business case framework, validated by the expert judgements. The further study needs to be elaborated by either the existing organization that use blockchain or assessment by the organization that will use blockchain to improve their supply chain management.

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