Numerical modeling of an umbrella arch as a pre-support system in difficult geological conditions: a case study

2015 ◽  
Vol 75 (1) ◽  
pp. 211-221 ◽  
Author(s):  
Ayub Elyasi ◽  
Mohammad Javadi ◽  
Taher Moradi ◽  
Javad Moharrami ◽  
Saeid Parnian ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Support System ◽  
Geological Conditions ◽  
Umbrella Arch

scholarly journals Support System for Tunnelling in Squeezing Ground of Qingling-Daba Mountainous Area: A Case Study from Soft Rock Tunnels

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xiuling Wang ◽  
Jinxing Lai ◽  
Rodney Sheldon Garnes ◽  
Yanbin Luo
Keyword(s):  
Support System ◽  
Strong Support ◽  
Mountainous Area ◽  
Squeezing Ground ◽  
Tunnel Face ◽  
Support Design ◽  
Tunnel Support ◽  
Geological Conditions ◽  
Rock Tunnels

Tunnelling or undertaking below-ground construction in squeezing ground can always present many engineering surprises, in which this complicated geology bring a series of tunnelling difficulties. Obviously, if the major affecting factors and mechanism of the structure damage in these complicated geological conditions are determined accurately, fewer problems will be faced during the tunnel excavation. For this study, reference is made to four tunnel cases located in the Qingling-Daba mountainous squeezing area that are dominated by a strong tectonic uplift and diversified geological structures. This paper establishes a strong support system suitable for a squeezing tunnel for the purpose of addressing problems exhibited in the extreme deformation of rock mass, structure crack, or even failure during excavation phase. This support system contains a number of temporary support measures used for ensuring the stability of tunnel face during tunnelling. The final support system was constructed, including some key techniques such as the employment of the foot reinforcement bolt (FRB), an overall strong support measure, and more reserved deformation. Results in this case study showed significant effectiveness of the support systems along with a safe and efficient construction process. The tunnel support system proposed in this paper can be helpful to support design and provide sufficient support and arrangement before tunnel construction in squeezing ground.

scholarly journals Support System Design for Deep Coal Mining by Numerical Modeling and a Case Study

2021 ◽  
Author(s):  
Shankar Vikram ◽  
Dheeraj Kumar ◽  
Duvvuri Satya Subrahmanyam
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
System Design ◽  
Coal Mining ◽  
Support System ◽  
Modeling Technique ◽  
Mine Design ◽  
Godavari Valley

Importance of numerical modeling in mine design gained pace after modern way of approach took birth through many variants. Methods such as Continuum and Discontinuum emerge as most effective in resolving certain issues. Cases such as heterogeneity, prevailing boundary conditions in continuum case and presence of discontinuities in other have provided solutions for many causes. A suitable support system is designed for deep virgin coal mining blocks of Godavari Valley Coalfield in India. This analysis is carried out using numerical modeling technique. The results show that the stresses at an angle to the level galleries are adverse. The level gallery/dip-raise may be oriented at 200 to 400 to reduce roof problems.

scholarly journals A Case Study on Large Deformation Failure Mechanism and Control Techniques for Soft Rock Roadways in Tectonic Stress Areas

2019 ◽  
Vol 11 (13) ◽  
pp. 3510 ◽  
Author(s):  
Xue ◽  
Gu ◽  
Fang ◽  
Wei
Keyword(s):  
Numerical Simulation ◽  
Large Deformation ◽  
Failure Mechanism ◽  
Support System ◽  
Soft Rock ◽  
Tectonic Stress ◽  
Geological Conditions ◽  
Soft Rock Roadway ◽  
Rock Roadway

Large deformation and failure of soft rock are pressing problems in the mining practice. This paper provides a case study on failure mechanisms and support approaches for a water-rich soft rock roadway in tectonic stress areas of the Wangzhuang coal mine, China. Mechanic properties of rock mass related to the roadway are calibrated via a geological strength index method (GSI), based on which a corresponding numerical simulation model is established in the Universal Discrete Element Code (UDEC) software. The failure mechanism of the roadway under water-saturating and weathering conditions is revealed by field tests and numerical simulation. It is found that the stress evolution and crack development are affected by weathering and horizontal tectonic stresses. The roadway roof and floor suffer from high stress concentration and continuous cracking, and are consequently seen with rock failure, strength weakening, and pressure relief. Unfortunately, the current support system fails to restrain rock weathering and strength weakening, and the roadway is found with serious floor heave, roof subsidence, and large asymmetric deformation. Accordingly, a new combined support system of “bolt–cable–mesh–shotcrete + grouting” is proposed. Moreover, numerical simulation and field testing are conducted to validate the feasibility and effectiveness of the proposed approach, the results of which demonstrate the capacity of the proposed new support method to perfectly control the surrounding rock. Findings of this research can provide valuable references for support engineering in the soft rock roadway under analogous geological conditions.

scholarly journals Analysis of support system for a conveyance tunnel in the higher Himalayan zone: A case study on Upper Tamakoshi HEP, Nepal

2021 ◽  
Vol 4 (1) ◽  
pp. 90-97
Author(s):  
Kalyan Paudyal
Keyword(s):  
Numerical Modeling ◽  
Stress Concentration ◽  
Support System ◽  
Empirical Method ◽  
Vital Role ◽  
Site Specific ◽  
Specific Data ◽  
Overburden Thickness ◽  
The Stability

After excavation, insitu stress conditions are changed which lead deformation due to the stress concentration. For the stability in the excavated tunnel profile, appropriate support system is essential. To recommend the support system, site specific data are used from Higher Himalayan Region of Nepal. Study is focused on 3 m and 6 m size inverted D Shaped tunnel with three different overburden thickness. For the analysis of support system: Empirical method, Analytical method and Numerical Modeling are performed. Result obtained from the different approaches for three different overburden heights as well as for both size tunnels are compared and finally required support system is recommended. It was found significant change in deformations while increase in size of tunnel. Overburden thickness is also playing the vital role in this parameter but size effect is more prominent.

Reflection on Learner-Led Study Abroad Events in a SAC from Three Perspectives: A Learner, an Administrative Staff Member, and an Advisor

Relay Journal ◽  
2020 ◽  
pp. 66-79
Author(s):  
Mizuki Shibata ◽  
Chihiro Hayashi ◽  
Yuri Imamura
Keyword(s):  
Study Abroad ◽  
Language Learning ◽  
Support System ◽  
Staff Member ◽  
Administrative Staff ◽  
Multiple Reflections ◽  
Learning Space ◽  
Japanese University ◽  
Staff Members

This paper reports on a case study of learner-led study-abroad events in the language learning space at a Japanese University. We present multiple reflections on the events from different perspectives: the event organizer (student), an administrative staff member, and a learning advisor working at the center. We also introduce the support system that a group of administrative staff members and learning advisors are in charge of helping learners to hold their events. Moreover, throughout our reflections, several factors that made the learner-led study-abroad events sustainable and successful are demonstrated.

scholarly journals Comparison between electrical resistivity tomography and tunnel seismic prediction 303 methods for detecting the water zone ahead of the tunnel face: A case study

2020 ◽  
Vol 12 (1) ◽  
pp. 1094-1104
Author(s):  
Nima Dastanboo ◽  
Xiao-Qing Li ◽  
Hamed Gharibdoost
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Geological Structure ◽  
Rock Properties ◽  
Electrical Tomography ◽  
Tunnel Face ◽  
Resistivity Tomography ◽  
Geological Conditions ◽  
Seismic Prediction

AbstractIn deep tunnels with hydro-geological conditions, it is paramount to investigate the geological structure of the region before excavating a tunnel; otherwise, unanticipated accidents may cause serious damage and delay the project. The purpose of this study is to investigate the geological properties ahead of a tunnel face using electrical resistivity tomography (ERT) and tunnel seismic prediction (TSP) methods. During construction of the Nosoud Tunnel located in western Iran, ERT and TSP 303 methods were employed to predict geological conditions ahead of the tunnel face. In this article, the results of applying these methods are discussed. In this case, we have compared the results of the ERT method with those of the TSP 303 method. This work utilizes seismic methods and electrical tomography as two geophysical techniques are able to detect rock properties ahead of a tunnel face. This study shows that although the results of these two methods are in good agreement with each other, the results of TSP 303 are more accurate and higher quality. Also, we believe that using another geophysical method, in addition to TSP 303, could be helpful in making decisions in support of excavation, especially in complicated geological conditions.

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