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excavation
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Excavation plan and preliminary support design of an underground control room using 3D analysis in soft and weathered rocks
, Article 6th European Conference on Numerical Methods in Geotechnical Engineering - Numerical Methods in Geotechnical Engineering, Graz, 6 September 2006 through 8 September 2006 ; 2006 , Pages 359-365 ; 0415408229 (ISBN); 9780415408226 (ISBN) ; Talebi, M ; Jafarzadeh, F ; Dianat Nejad, M ; Sharif University of Technology
Taylor and Francis/ Balkema
2006
Abstract
In this paper, proper and safe planning of excavation method and design of support system in very weak rocks with case study of control room of Silveh dam are discussed. Silveh earth-storage dam, with 102 m height; is under construction in North-West of Iran. Due to numerous and various tectonic occurrences, the area of dam site is known as a high activity zone of Iran. In purposed location of control room, bedrock contains mostly weathered and crushed Shale and Schist. 60 m overburden and finite aquifers are another specific concern of this project. In this paper by using 3D finite element modeling, different stages of excavation and support system installation have been analyzed for the...
Three-dimensional numerical analysis of corner effect of an excavation supported by ground anchors
, Article International Journal of Geotechnical Engineering ; 2019 ; 19386362 (ISSN) ; Ahmadi, M. M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
This paper presents a case study and numerical simulations of a corner of a deep excavation in Tehran supported by soldier piles and ground anchors. This study focuses on the differences between 2D and 3D numerical modelling in estimating the wall deflection at the corner locations of the excavation. Furthermore, the performance of modelling with Mohr–Coulomb constitutive law was compared with the result of a hardening soil model. The modelling procedure was calibrated against a full-scale instrumented tieback wall at Texas A&M University and the monitoring data of the excavation project. The results indicated that the hardening soil model yields reasonable predictions of wall deflection in...
Numerical investigation of stability of deep excavations supported by soil-nailing method
, Article Geomechanics and Geoengineering ; 2019 ; 17486025 (ISSN) ; Maleki, J ; Aghakhani, N ; Yousefi, M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Deep excavation in urban areas can cause instability problems due to significant settlement at the ground surface and large movements at the excavation facing walls. One of the most popular methods used to stabilise these excavations is utilising soil-nailing method. This method has also been widely used to stabilise natural slopes and earth retaining structures. Because of the complexity involved in the mechanism of this stabilising system due to interacting effects of the soil, nails, grout and shotcrete, numerical modelling with high accuracy should be used to analyse the behaviour of the soil-nailed walls. Considering all aspects of soil-structure interaction in the present research, a...
Three-dimensional numerical analysis of corner effect of an excavation supported by ground anchors
, Article International Journal of Geotechnical Engineering ; 2019 ; 19386362 (ISSN) ; Ahmadi, M. M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
This paper presents a case study and numerical simulations of a corner of a deep excavation in Tehran supported by soldier piles and ground anchors. This study focuses on the differences between 2D and 3D numerical modelling in estimating the wall deflection at the corner locations of the excavation. Furthermore, the performance of modelling with Mohr–Coulomb constitutive law was compared with the result of a hardening soil model. The modelling procedure was calibrated against a full-scale instrumented tieback wall at Texas A&M University and the monitoring data of the excavation project. The results indicated that the hardening soil model yields reasonable predictions of wall deflection in...
Numerical investigation of stability of deep excavations supported by soil-nailing method
, Article Geomechanics and Geoengineering ; 2019 ; 17486025 (ISSN) ; Maleki, J ; Aghakhani, N ; Yousefi, M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Deep excavation in urban areas can cause instability problems due to significant settlement at the ground surface and large movements at the excavation facing walls. One of the most popular methods used to stabilise these excavations is utilising soil-nailing method. This method has also been widely used to stabilise natural slopes and earth retaining structures. Because of the complexity involved in the mechanism of this stabilising system due to interacting effects of the soil, nails, grout and shotcrete, numerical modelling with high accuracy should be used to analyse the behaviour of the soil-nailed walls. Considering all aspects of soil-structure interaction in the present research, a...
Numerical investigation of stability of deep excavations supported by soil-nailing method
, Article Geomechanics and Geoengineering ; Volume 16, Issue 6 , 2021 , Pages 434-451 ; 17486025 (ISSN) ; Maleki, J ; Aghakhani, N ; Yousefi, M ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
Deep excavation in urban areas can cause instability problems due to significant settlement at the ground surface and large movements at the excavation facing walls. One of the most popular methods used to stabilise these excavations is utilising soil-nailing method. This method has also been widely used to stabilise natural slopes and earth retaining structures. Because of the complexity involved in the mechanism of this stabilising system due to interacting effects of the soil, nails, grout and shotcrete, numerical modelling with high accuracy should be used to analyse the behaviour of the soil-nailed walls. Considering all aspects of soil-structure interaction in the present research, a...
Study the Effect of Staged Construction and Behavior of Concave Corner of Excavation Stabilized by Soldier Piles with Pretensioned Anchor by 3D Numerical Modeling
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
In recent years, due to the development of cities and population growth, the number of underground floors and the depth of excavations have increased. Sustainability of excavation and control of deformation due to excavation process has always been considered as one of the important issues in geotechnical engineering. One of the most commonly used systems for deep excavation, especially in urban areas, is the soldier pile wall with tiebacks. This system consists of anchoring on soldier piles that are performed at horizontal distances around the excavation range. The cables have two parts. Unbond and bond length that, when pretensioned, have the task of transfering load out of the wedge of...
An innovative method of large space underground construction in soft and shallow ground using concrete arch pre-supporting system, CAPS method
, Article ITA-AITES World Tunnel Congress 2016, 22 April 2016 through 28 April 2016 ; Volume 1 , 2016 , Pages 548-557 ; 9781510822627 (ISBN) ; Sharif University of Technology
Society for Mining, Metallurgy and Exploration
Abstract
Construction of underground structures in urban areas is a very challenging work. There are generally two methods of construction, an open cut-and-cover and underground method. To eliminate the subsurface and surface disturbance and street traffic problems, underground method is preferred. The stress redistribution caused by underground excavation induces movements and deformation in the earth mass and ultimately at the ground surface. This is more pronounced in large space excavations. Generally pre-supporting system is used to control ground deformation and thus enhance its stability. In this paper an innovative pre-supporting system is presented. Concrete Arch Pre-supporting System (CAPS)...
An innovative method of large space underground construction in soft and shallow ground using concrete arch pre-supporting system
, Article World Tunnel Congress, WTC 2019 and the 45th General Assembly of the International Tunnelling and Underground Space Association, ITA-AITES 2019, 3 May 2019 through 9 May 2019 ; 2019 , Pages 2995-3004 ; 9781138388659 (ISBN) ; Sharif University of Technology
CRC Press/Balkema
2019
Abstract
Construction of underground structures in urban areas is a very challenging work. There are generally two methods of their construction, an open cut-and-cover and underground method. To eliminate the subsurface and surface disturbance and street traffic problems, underground method is preferred. The stress redistribution caused by underground excavation induces movements in the earth mass and ultimately at the ground surface. This is more pronounced in large space excavations. Generally pre-supporting system is used to control ground deformation and thus enhance its stability. In this paper an innovative pre-supporting system is presented. Concrete Arch Pre-supporting System (CAPS) is...
An innovative method of large space underground construction in soft and shallow ground using concrete arch pre-supporting system
, Article World Tunnel Congress, WTC 2019 and the 45th General Assembly of the International Tunnelling and Underground Space Association, ITA-AITES 2019, 3 May 2019 through 9 May 2019 ; 2019 , Pages 2995-3004 ; 9781138388659 (ISBN) ; Sharif University of Technology
CRC Press/Balkema
2019
Abstract
Construction of underground structures in urban areas is a very challenging work. There are generally two methods of their construction, an open cut-and-cover and underground method. To eliminate the subsurface and surface disturbance and street traffic problems, underground method is preferred. The stress redistribution caused by underground excavation induces movements in the earth mass and ultimately at the ground surface. This is more pronounced in large space excavations. Generally pre-supporting system is used to control ground deformation and thus enhance its stability. In this paper an innovative pre-supporting system is presented. Concrete Arch Pre-supporting System (CAPS) is...
Assessing the functionality of different constitutive models in predicting the behavior of deep stabilized excavations
, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019; 14 October 2019 through 18 October 2019 ; 2020 ; Garakani, A. A ; Shahrabi, M. M ; Sharif University of Technology
Asian Regional Conference on Soil Mechanics and Geotechnical Engineering
2020
Abstract
In this study, application of Limit Equilibrium (LE) and Finite Element Model (FEM) analyses have been presented and discussed for support design of a 30-m deep excavation in Tehran. A combination of nailing and strand anchorage with block system were designed and used to support the vertical cut in multiple steps of excavation. In this regard, safety factors have been assessed based on LEM using Mohr-Coulomb model, while deformations were estimated using the Hardening Soil model in an FEM platform. Comparison of the design models and field monitoring of deformations indicate a reasonably well performed engineering approach which can be implemented in similar projects in dense urban areas....
A comprehensive FE study for design of anchored wall systems for deep excavations
, Article Tunnelling and Underground Space Technology ; Volume 122 , 2022 ; 08867798 (ISSN) ; Pak, A ; Yousefi, M ; Aghakhani, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Anchored wall system is one of the common methods used for deep excavation stabilization adjacent to sensitive structures in urban areas. A key aspect of the stability analysis of deep excavations is the amount of deformations occurring on the facing wall and the adjacent structures. In this research, a large number of parametric studies considering all aspects of soil-structure interaction is carried out for different excavation geometries to find the optimal design, and the outcome is shown in the form of design tables and charts. Also, by a GA-PSO algorithm and using the large database obtained from the numerical simulations, a simple equation is developed that can predict the deflections...
Simulation of New Methods in Ventilation of Underground Station Sand Tunnels
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, bijan (Supervisor)
Abstract
Due to growth of the number of passengers in subway transportation systemsthe capacity of the metro stations are on the rise.The generated heat loads in subway line shall be increased by thegrowth of the its capacity. As a result, current subway ventilation systems cannot provide comfort conditions for passengers. Nowadays, modern ventilation systems are designedto improve ventilation performance and to create suitable thermal conditions. Among of these, the under platform andover track exhaust systems and use of platform screen doors can be Cited. The aim of this study is three-dimensional simulation of air flow in modern ventilation systems of subway stations. Numerical simulations are in...
Optimization of the Urban Tunnels Final Lining
, M.Sc. Thesis Sharif University of Technology ; Sadaghiani, Mohammad Hossein (Supervisor)
Abstract
Tunnels are considered as one of the vital arteries of each country. In this concept, one of the most notable issues is designing of tunnel lining systems. Due to the increase of investments in tunnels and the progress of machinery and tunnel technology is needed for an optimal tunnel lining systems more than the past. The effect of initial lining system is not considered in designing of final lining systems, and this section is assumed to be omitted. In general, in this project, the final lining system of urban tunnels will be optimized by finite element method. This method is used by Abaqus software for analysis and the modeling. The purpose of this work is optimization of design lining...
Behavior of Underground Passagway and Subway Station for Earthquake Loads
, M.Sc. Thesis Sharif University of Technology ; Sadaghiani, Mohammad Hossein (Supervisor)
Abstract
A brief overview of the proposed research, its aims, engineering relevance and applications Underground space has long been exploited through the history to fulfill different human necessities. Underground facilities built in areas subject to earthquake activity must withstand both seismic and static loads. Some underground structures have experienced significant damage in recent large earthquakes. Tehran is located in seismic zone and investigation and research on the subject has significant role in design and construction of underground spaces for earthquake loads. Underground structures are complex structures which consist of different parts Such as passage way and platform space. Passage...
Numerical Modeling of Deep Excavation Behavior and It’s Comparision with Monitoring Data
, M.Sc. Thesis Sharif University of Technology ; Jafarzade, Fardin (Supervisor)
Abstract
Evaluating the magnitude and distribution of ground movements adjacent to an excavation wall is an important part of the design process when excavating in an urban environment. In urban environment, this movement controlled by monitoring and the result of monitoring need to compared with analysis result. 2D analysis can’t explain Three dimesional effects in excavation. This effects caused by the relatively high stiffness at the corners of an excavation lead to smaller ground movements near the corners and larger ground movement towards the middle of the excavation excavation's wall. Plane strain Ratio (PSR) quantify the magnitude of 3D corner effect in excavation defined as the ratio of the...
The Behavior of Supporting Structures with Pretension Anchors by Geotechnical Softwares
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
In recent years, due to urban expansion and population growth, number of floors and excavations depth has increased. Stabilization of excavations is one of the most important issues in geotechnical engineering. Today, one of the most widely used methods that is used in deep excavations is brace soil by steels and pretension them. In this thesis tries to evaluate static behavior of flexible supporting structures with pretension anchors by using PLAXIS2D, FLAC3D and GEOSTUDIO softwares. The objective of this modeling is better understanding the static behavior of walls, comparing the two and three dimensional modeling and the effect of corners of excavation on deformation. The results shows...
Three-dimensional numerical analysis of corner effect of an excavation supported by ground anchors
, Article International Journal of Geotechnical Engineering ; Volume 16, Issue 7 , 2022 , Pages 903-915 ; 19386362 (ISSN) ; Ahmadi, M. M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
This paper presents a case study and numerical simulations of a corner of a deep excavation in Tehran supported by soldier piles and ground anchors. This study focuses on the differences between 2D and 3D numerical modelling in estimating the wall deflection at the corner locations of the excavation. Furthermore, the performance of modelling with Mohr–Coulomb constitutive law was compared with the result of a hardening soil model. The modelling procedure was calibrated against a full-scale instrumented tieback wall at Texas A&M University and the monitoring data of the excavation project. The results indicated that the hardening soil model yields reasonable predictions of wall deflection in...
An Integrated Simulation-DEA Approach to Multi-criteria Ranking of Scenarios for Execution of Operations in a Construction Project
, M.Sc. Thesis Sharif University of Technology ; Mahlooji, Hashem (Supervisor)
Abstract
Before a construction project gets under way an attempt is made to examine different ways and scenarios for its implementation. Through such a process the more appropriate scenarios should be selected based on several criteria that are not necessarily at the same level in terms of importance. The purpose of this study is to examine different scenarios for implementing operations in the pre-construction phase of a project, based on several competing criteria with different importance levels in order to achieve a more efficient execution plan. This paper presents a new framework that integrates discrete event simulation (DES) and data envelopment analysis (DEA) to rank different scenarios for...
Effect of a gap opening on the conductance of graphene superlattices
, Article Solid State Communications ; Volume 150, Issue 13-14 , 2010 , Pages 655-659 ; 00381098 (ISSN) ; Esmailpour, A ; Asgari, R ; Elahi, M ; Rahimi Tabar, M. R ; Sharif University of Technology
2010
Abstract
The electronic transmission and conductance of a gapped graphene superlattice were calculated by means of the transfer-matrix method. The system that we study consists of a sequence of electron-doped graphene as wells and hole-doped graphene as barriers. We show that the transmission probability approaches unity at some critical value of the gap. We also find that there is a domain around the critical gap value for which the conductance of the system attains its maximum value