scholarly journals Mechanical aspects of construction of new TBM tunnel under existing structures

2021 ◽  
Author(s):  
Wu Ke ◽  
Zheng Zhang ◽  
Chen Shu Li ◽  
Sheng Lei Zhou ◽  
Hui Jia Zhao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Complex Mixture ◽  
Simulation Software ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Ground Structure ◽  
Existing Structures ◽  
Tbm Cutter ◽  
Cutter Head ◽  
Surrounding Soil

Abstract It is inevitable for the construction of subways to pass under the existing structures in the city; this will cause settlement of the existing structures and affect their safety. The soil is a complex mixture, and hence it is difficult to determine the damage caused by construction using tunnel boring machine (TBM) method to the stress balance of the surrounding soil. Normally, settlement and uplift of the surface are caused during tunneling. Therefore, large-scale 3D simulations are needed to study the interaction between mechanically driven tunnel construction and the surrounding soil to estimate the expected settlement and related damage risks to the existing structures, especially in tunnel construction in urban areas. Qingdao Metro Line 1 in the Haixiao section (Xiaocunzhuang and Haiboqiao stations) was taken up as the research object to study the trend and degree of the effect of TBM tunnel construction using the numerical simulation software Midas GTS NX. The numerical simulation results and measured data were used for the reliability analysis to study the influence of different digging speeds and pressures in TBM construction on ground subsidence, and the effect of vibrations generated at the tunnel face by the TBM cutter head on the ground structure. It is shown that when other factors remain unchanged, the faster the driving speed, the smaller the ground settlement; the higher the surrounding rock pressure, the smaller the ground settlement. The vibration of the ground structure caused by the TBM cutter head complies with the relevant specifications. During construction, the driving parameters should be selected suitably depending on the available budget.

scholarly journals Mechanical Aspects of Construction of New TBM Tunnel Under Existing Structures

2021 ◽  
Author(s):  
Wu Ke ◽  
Zhang zheng ◽  
Li Shuchen ◽  
Zhou leisheng ◽  
Zhao Jiahui ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Complex Mixture ◽  
Simulation Software ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Ground Structure ◽  
Existing Structures ◽  
Tbm Cutter ◽  
Cutter Head ◽  
Surrounding Soil

AbstractIt is inevitable for the construction of subways to pass under the existing structures in the city; this will cause settlement of the existing structures and affect their safety. The soil is a complex mixture, and hence it is difficult to determine the damage caused by construction using tunnel boring machine (TBM) method to the stress balance of the surrounding soil. Normally, settlement and uplift of the surface are caused during tunneling. Therefore, large-scale 3D simulations are needed to study the interaction between mechanically driven tunnel construction and the surrounding soil to estimate the expected settlement and related damage risks to the existing structures, especially in tunnel construction in urban areas. Qingdao Metro Line 1 in the Haixiao section (Xiaocunzhuang and Haiboqiao stations) was taken up as the research object to study the trend and degree of the effect of TBM tunnel construction using the numerical simulation software Midas GTS NX. The numerical simulation results and measured data were used for the reliability analysis to study the influence of different digging speeds and pressures in TBM construction on ground subsidence, and the effect of vibrations generated at the tunnel face by the TBM cutter head on the ground structure. It is shown that when other factors remain unchanged, the faster the driving speed, the smaller the ground settlement; the higher the surrounding rock pressure, the smaller the ground settlement. The vibration of the ground structure caused by the TBM cutter head complies with the relevant specifications. During construction, the driving parameters should be selected suitably depending on the available budget.

Prediction of Shield Tunnelling-Induced Ground Settlement Considering Soil-Water Coupled and around Soil Disturbance Damage

2010 ◽  
Vol 168-170 ◽  
pp. 357-364
Author(s):  
Ji Feng Liu ◽  
Bo Liu ◽  
Hui Zhi Zhang
Keyword(s):  
Numerical Simulation ◽  
Soil Water ◽  
Ground Surface ◽  
Soil Disturbance ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Ground Surface Settlement ◽  
Shield Tunnelling

to evaluate the influence of soil-water coupled and shield tunnel construction induced around soil disturbance damage on ground surface settlement, the process of shield tunnel construction induced around soil disturbance is analyzed, the FLAC3D numerical simulation are carried out, and a newly-modified tunnelling-induced ground settlement calculation method based on disturbance degree of around soil and soil-water coupled is presented, and these methods are applied in case of Beijing Metro 10thLine. It is indicated that considering the influence of the shield tunnelling-induced around soil disturbance damage, and soil-water coupled induced soil properties weakening and the excess pore water pressure dissipating induced soil consolidation to the ground surface settlement are necessary, the calculating result of the newly-modified surface settlement prediction method, and the result FLAC3D numerical simulation all agree well with in-site observed data of Beijing Metro 10th Line.

Control Standard of Ground Surface Settlement Induced by Running Tunnel Construction in Beijing Subway

2011 ◽  
Vol 117-119 ◽  
pp. 721-725 ◽  
Author(s):  
Cheng Ping Zhang ◽  
Li Min Li ◽  
He Li ◽  
Jian Chen Wang
Keyword(s):  
Numerical Simulation ◽  
Ground Surface ◽  
Control Valve ◽  
Surface Settlement ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Simulation Based ◽  
Ground Surface Settlement ◽  
Subway Construction ◽  
Beijing Subway

Ground settlement, especially the ground surface settlement induced by subway tunneling is an important issue. However, there is no an agreed standard for controlling ground surface settlement during the subway construction at present. The control standard of ground surface settlement was studied using the methods of statistical analysis and numerical simulation based on the running tunnel in Beijing subway. According to the research results, a conclusion could be obtained that the ground surface settlement can be controlled within 40 mm using the general construction measures in Beijing subway running tunnel construction, and furthermore, the settlement of 40mm will not damage the existing nearby structures and utilities including neighboring buildings, bridges and pipelines, etc. So the control valve of 40 mm is rational, which can be adopted as the control standard of ground surface settlement induced by running tunnel construction in Beijing subway.

scholarly journals A Novel Method for Analyzing the Factors Influencing Ground Settlement during Shield Tunnel Construction in Upper-Soft and Lower-Hard Fissured Rock Strata considering the Coupled Hydromechanical Properties

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Yan Wang ◽  
Yongjun Zhang ◽  
Zhen Zhu ◽  
Mingqing Du ◽  
Yi Qi
Keyword(s):  
Neural Network ◽  
Numerical Simulation ◽  
Elastic Moduli ◽  
Coarse Sand ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Factors Influencing ◽  
Fissured Rock ◽  
Rock Strata

Focusing on the special stratum conditions of upper-soft and lower-hard fissured rock strata, this paper conducts quantitative research and analysis on the factors influencing the ground settlement caused by shield tunnel construction considering the coupled hydromechanical properties and presents a corresponding numerical simulation-artificial neural network-Bayesian network- (NS-ANN-BN-) based method. In this method, with a subway shield tunnel as the engineering context, three numerical models are established, in which the shield tunnel is located in soft strata, the shield tunnel is located in semisoft and semihard strata, or the shield tunnel is located in hard strata. According to the numerical simulation (NS) calculations, the ground settlement values under the three types of strata are 38.96 mm, 10.42 mm, and 3.13 mm, respectively. A radial basis function artificial neural network (RBF-ANN) is used to establish the nonlinear mapping relationship between the stratum parameters and the ground settlement, and the training samples and test samples are generated through NS to train the RBF-ANN. After the training is completed, the accuracy of the neural network meets the requirements. The elastic moduli of coarse sand~gravel sand k3 and moderately weathered rhyolite k4 and the cohesion of moderately weathered rhyolite c4 are selected as the key parameters. A large number of training cases are generated through the RBF-ANN, and the Bayesian network (BN) prior probability is calculated by self-learning. A BN model of ground settlement for shield tunnel construction in the upper-soft and lower-hard fissured rock strata is established. The BN back analysis method is used to quantitatively analyze the influencing factors of the ground settlement. The results show that when the tunnel is located in soft strata, the surface settlement is mainly affected by parameter k3. When the ground settlement increases considerably, the three parameters all have a strong influence. When the tunnel is located in semisoft and semihard strata, the influence of the three parameters on the ground settlement is weak. When the tunnel is located in hard strata, the ground settlement is mainly affected by parameter k4. When the ground settlement greatly increases, parameters k3 and c4 have less influence. When the tunnel is located in strata with different soft-hard ratios, the ground settlement is mainly affected by the elastic moduli of coarse sand~gravel sand and moderately weathered rhyolite. This method can provide a reference for the ground settlement analysis of shield tunnel construction in areas with similar fissured rock strata.

scholarly journals Analysing the Effect of Tunnel Construction on Existing Structure by Using Analytical and Numerical Method

2021 ◽  
Vol 9 (VII) ◽  
pp. 3961-3971
Author(s):  
NInad Choudhary
Keyword(s):  
Numerical Method ◽  
Urban Areas ◽  
Suitable Method ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Underground Construction ◽  
Existing Structures ◽  
Geological Conditions ◽  
Existing Structure

Underground construction in urban areas is a challenging work to carry out and includes a lot of factors to be considered. In varying geological conditions, it becomes very difficult as there are various faults and fracture, so it requires a proper investigation to be done before starting of the project. The aim of this report is to determine the effects of tunneling on existing structures and tunnel surrounding due to tunnelling work, like crack in structure, vibrations caused to the above structure and ground settlement. To identify the movements caused and giving a solution by using the RS2 software and deciding the best suitable method for Construction of tunnel.

Numerical Simulation of Filling and Solidification in Sand Casting by Procast

2013 ◽  
Vol 791-793 ◽  
pp. 550-553 ◽  
Author(s):  
Dong Dong Han ◽  
Cheng Jun Wang ◽  
Juan Chang ◽  
Lei Chen ◽  
Huai Bei Xie
Keyword(s):  
Numerical Simulation ◽  
Heat Dissipation ◽  
Solidification Process ◽  
Simulation Software ◽  
Sand Casting ◽  
Production Costs ◽  
Raw Material ◽  
Casting Defects ◽  
Three Dimension ◽  
Filling And Solidification

At present, pulley produced in China has been able to meet the demand of domestic and international markets. But there are many problem of the pulley industry in our country, such as too many production enterprises and the low level of export products. And as components of drive system are light weight and raw material price of pulley casting are rising, manufacturing requirements of the pulley are also more and more high. Aiming at the casting defects of pulley that enterprise current product, pulley casting blank model of common material HT250 be made by three-dimension software, numerical simulation of filling and solidification process for pulley sand casting by the casting simulation software Procast, the size and location of the various casting defects were forecasted and analyzed, reflecting the pulley filling and solidification process of the actual situation, due to the thicker pulley rim and less heat dissipation, position of shrinkage is close to the middle of rim [, a method of eliminating defects is proposed to realize sequential solidification, and thus to minimize porosity shrinkage and improve casting performance and reduce casting time and reduce production costs.

Case Study on Modeling Fire Action Complexity in Fire Safety Engineering of Structures

2017 ◽  
Vol 21 ◽  
pp. 102-107
Author(s):  
Constantin Sorin Scutarasu ◽  
Dan Diaconu-Şotropa ◽  
Marinela Barbuta
Keyword(s):  
Numerical Simulation ◽  
Fire Safety ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Structural Safety ◽  
Modular Organization ◽  
Field Of Study ◽  
Safety Design ◽  
Fire Safety Design ◽  
Technical Regulations

Important goals in the fire safety design, such as preventing loss of life and goods damage, are achieved by maintaining the stability of structures exposed to fire for a period of time established by norms and standards. Real fire scenarios confirm that the specific technical regulations which actually have a prescriptive character (both national and international) do not deal with sufficient possibilities regarding the assessment of structural fire safety. The new approach on structural safety, based on engineering notions, gives us additional prospects on it and it is included in the issues of the fire safety design of structures. A relatively new field of study, known by a few professionals focused on fire safety (but well acknowledged in the research area), fire safety design met with lots of changes and restructuring of the governing concepts and procedures and of the information with which they operate, due to the fast accumulation of experience in this area of engineering activity. Consequently, after countries such as Australia, Canada, New Zeeland or USA provided towards professionals specific technical regulations for fire safety design, groups of experts in these aforementioned countries have joined their forces to try to diminish the differences that exists between those regulations and to give a unitary character to them, a better conceptualized engineering approach of the fire safety design. The result: occurrence of the publication International Fire Engineering Guidelines (last edition from 2005). The systematic approach of fire safety design in constructions pointed, once again, the possibility of modular organization of this field of study, the relations between modules being established according to the objective or objectives in the fire safety design for a specified building. This article aims to put forward, from this modularized perspective, the study of the fire safety design of a building exposed to fire; hence, the practical part of the article exhibits the numerical simulation of initialization and development of the fire process for a large scale religious building. The main features of the building represent the amount of space that facilitates the spreading of smoke and warm gases and which increases the risk of damaging the structural reinforced concrete elements. Application calls to specific numerical simulation with a higher degree of credibility, such as those realized by the FDS (Fire Dynamics Simulation) software.

Impact of Double-O-Tube Shield Tunnel Construction on Grillage Beams Foundation Frame Building

2011 ◽  
Vol 71-78 ◽  
pp. 32-36 ◽  
Author(s):  
Xin Jiang Wei ◽  
Jie Hong ◽  
Gang Wei
Keyword(s):  
Principal Stress ◽  
Differential Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Foundation Settlement ◽  
Ground Settlement ◽  
Shield Tunneling ◽  
Frame Building ◽  
Shield Machine ◽  
The Impact

Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-O-Tube (DOT) shield tunnel was simulated by 3D MIDAS/ GTS software, and the impact of construction on the building was analyzed. The results show that: the ground settlement trough caused by DOT shield tunnel can be fitted by peck formula; during the passage of the shield tunneling through the building, the settlement of the building increased and settlement trough was wilder; the settlement was stable and had a little rebound when shield machine already passed the building; with the increase of driving distance, the first principal stress P1 increased and then was stable; with the increase of L, the shape of foundation settlement curve changed, and the maximum differential settlement between columns increased but was small.

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