scholarly journals Numerical Modelling of The Behavior of Tunnel in Soft Surrounding Rock. A Case Study of Djebel El-Ouahch Tunnel, Algeria.

2021 ◽  
Author(s):  
Barkane Aicha ◽  
Sami Mezhoud
Keyword(s):  
Reference Model ◽  
Soil Behavior ◽  
Tunnel Excavation ◽  
Circular Section ◽  
Geological Conditions ◽  
The Stability ◽  
Tunnel Cross Section ◽  
Calculation Code ◽  
Surrounding Soil

Abstract The response of a massif to stresses generated by tunnel excavation depends essentially on the geological conditions, the geometry of the tunnel and its underground position. The major problem related to the construction of these structures is to ensure the stability of the whole tunnel-ground, by controlling the various deformation generated during the constructionIn this context, the present paper examines the effect of these conditions on the behavior of tunnels and the surrounding soil. The study is applied to a real tunnel, in this case the tunnel of Djebel El Ouahch, Algeria was taken as a reference model. The research includes a parametric study to evaluate the effect of several parameters on the behavior of the tunnel and surrounding soil such as the tunnel anchoring depth, the tunnel-soil interface rate, and the shape of the tunnel cross section. The analysis is performed using the PLAXIS 3D TUNNEL calculation code with an elastoplastic Mohr-coulomb model for the soil behavior. The results show that the strongest and most stable position is the mid-deep tunnel with a circular section, with a non-slip interface between the tunnel and the ground. These outcomes can help to understand the effects of various influences parameters which control the stability of the tunnel in a soil with bad characteristics.

Analysis of Seepage Field of Highway Tunnel Excavation by Finite Difference Method

2014 ◽  
Vol 638-640 ◽  
pp. 798-803
Author(s):  
Yong Tao Zhang
Keyword(s):  
Finite Difference ◽  
Circulatory System ◽  
Surrounding Rock ◽  
Design Parameters ◽  
Seepage Field ◽  
Tunnel Excavation ◽  
Highway Tunnel ◽  
Geological Conditions ◽  
Fracture Development ◽  
The Stability

As the excavation of tunnels, there are new channels of the groundwater drainage. The original supply of the circulatory system has been destroyed. The effects of groundwater to rock mass of surrounding rock are aggravated. In this paper, combined with a new highway tunnel project, the model is built according to the design parameters and the site engineering geological conditions of the tunnel. The fluid-structure interaction module of the finite difference software FLAC3D is used for the research on tunnel excavation. The distribution of seepage field, the stability of surrounding rock and rock deformation under saturated conditions during the tunnel excavation have been analyzed. The simulation results have certain guiding meaning on fracture development, the stability design of tunnels in water-rich stratum and the design and construction of anti-drainage.

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 Landslide Triggered by Orthogonal Tunnel Excavation and Prevention Measures in Jimei Village, Sichuan Province, China

2021 ◽  
Author(s):  
zhongfu wang ◽  
Han Dong Liu ◽  
Si Ming He ◽  
Yunfeng Fang
Keyword(s):  
Numerical Simulation ◽  
Interaction Mechanism ◽  
Tunnel Construction ◽  
Prevention Measures ◽  
Tunnel Excavation ◽  
Ancient Landslide ◽  
Site Monitoring ◽  
Geological Conditions ◽  
Landslide Deformation ◽  
The Stability

Abstract The axis of highway tunnels constructed in mountains under complex geological conditions is usually orthogonal to the section of potential landslide. The tunnel construction may lead to landslide, which then may result in the deformation and/or cracking of tunnels. Therefore, it is very important and practical for tunnel projects to study the complex interaction mechanism between orthogonal tunnel and landslide and provide appropriate prevention measures for tunnel. This paper, on the base of geological survey, on-site monitoring and numerical simulation, analyzed the deformation and reason of an ancient landslide revived by tunnel construction and studied the prevention measures for tunnel. The results show that the reason for the revival of the ancient landslide resulted mainly from the tunnel construction through sliding surface, and the ancient landslide is generally stable because most landslide deformation occurred beyond the tunnel and in the upper part of landslide. The numerical simulation was used to optimize the tunnel prevention scheme by the analysis to the stability, stresses and deformation of landslide based on stress-strain control theory. The original anti-slide pile design was cancelled and finally the tunnel is reinforced by upper soil removal and moving upper soil into toe. This tunnel has successfully completed and are under good operation. The used prevention measures were proven to be effective according to the monitoring data about displacements and stress of landslide and tunnel during operation period, and saved about seven million US$. The research results in this paper may offer a beneficial reference to projects with similar geological conditions.

Applications of random graphs

2017 ◽  
Author(s):  
A.C.C. Coolen ◽  
A. Annibale ◽  
E.S. Roberts
Keyword(s):  
Social Networks ◽  
Random Graphs ◽  
Interaction Network ◽  
Power Grids ◽  
Protein Protein Interaction ◽  
Topological Features ◽  
First Case ◽  
The Stability ◽  
Protein Protein Interaction Network

This chapter reviews graph generation techniques in the context of applications. The first case study is power grids, where proposed strategies to prevent blackouts have been tested on tailored random graphs. The second case study is in social networks. Applications of random graphs to social networks are extremely wide ranging – the particular aspect looked at here is modelling the spread of disease on a social network – and how a particular construction based on projecting from a bipartite graph successfully captures some of the clustering observed in real social networks. The third case study is on null models of food webs, discussing the specific constraints relevant to this application, and the topological features which may contribute to the stability of an ecosystem. The final case study is taken from molecular biology, discussing the importance of unbiased graph sampling when considering if motifs are over-represented in a protein–protein interaction network.

Supplier Development at LG Electronics

2020 ◽  
Author(s):  
Hyojin Kim ◽  
Daesik Hur ◽  
Tobias Schoenherr
Keyword(s):  
Management Practice ◽  
Digital Technologies ◽  
Supply Management ◽  
Future Research ◽  
Supplier Development ◽  
Environmentally Conscious ◽  
Competitive Capabilities ◽  
The Stability ◽  
Buyer Firm

Supplier development has been a critical supply management practice since the 1990s. In many instances, it has even become imperative for buyer firms to support and prepare their supply bases for uncertain economic and market environments, socially and environmentally conscious customers, advances in digital technologies, and increasing competition. Yet, research that approaches supplier development with the objective to advance all these dimensions in an integrated fashion is scarce. This study fills this void by exploring how a buyer firm may address these emerging challenges in its supply base. Specifically, an in-depth case study of LG Electronics explores how the firm designs and operates multidimensional supplier development activities to foster the stability and sustainability of its supply base while enhancing its core suppliers’ competitive capabilities. This chapter illustrates how supplier development can be taken to the next level, presents implications for managerial practice, and outlines promising future research avenues.

Capturing Transformative Moments in a Participatory Values-Based Event

2021 ◽  
pp. 154134462199624
Author(s):  
Felix Okechukwu Dike ◽  
JohnBosco Chika Chukwuorji
Keyword(s):  
Transformative Learning ◽  
Learning Outcomes ◽  
Study Design ◽  
Present Moment ◽  
Case Study Design ◽  
Fresh Perspective ◽  
The Stability

The theory of transformative learning (TL) has been criticized secondhand for its lack of clarity in capturing and explaining in detail the processes undergone by learners who are going through TL experiences and their link to learning outcomes. Using a case study design, and carefully synthesized TL processes (TLPs) from Mezirow’s TL theory, we present—moment by moment—the TLPs linked to outcomes identified among a group of teachers who participated in a values-based workshop. Participants were followed through interviews for over 72 weeks to trace the stability of their TL outcome. TL processes identified were compared to Mezirow’s 10 processes. The article discusses ontological transformations gained and offers fresh perspective to identifying TLPs that can be linked to outcomes.

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.

scholarly journals The effect of flexural–torsional buckling on the stability of timber members: a case study

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Osama A. B. Hassan
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
List Type ◽  
Torsional Buckling ◽  
Solution Methods ◽  
Simplified Solution ◽  
The Stability ◽  
Flexural Torsional Buckling ◽  
Building Engineering

Abstract This study investigates the stability of timber members subjected to simultaneously acting axial compression and bending moment, with possible risk for torsional and flexural–torsional buckling. This situation can occur in laterally supported members where one side of the member is braced but the other side is unbraced. In this case, the free side will buckle out of plane while the braced side will be prevented from torsional and flexural–torsional buckling. This problem can be evident for long members in timber-frame structures, which are subjected to high axial compression combined with bending moments in which the member is not sufficiently braced at both sides. This study is based on the design requirement stated in Eurocode 5. Solution methods discussed in this paper can be of interest within the framework of structural and building Engineering practices and education in which the stability of structural elements is investigated. Article Highlights This case study investigates some design situations where the timber member is not sufficiently braced. In this case, a stability problem associated with combined torsional buckling and flexural buckling can arise. The study shows that the torsional and/or flexural–torsional buckling of timber members can be important to control in order to fulfil the criteria of the stability of the member according to Eurocode 5 and help the structural engineer to achieve safer designs. The study investigates also a simplified solution to check the effect of flexural torsional buckling of laterally braced timber members.

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