Monitoring and Numerical Simulation of the Supporting of the Inverted Side Wall Shaft

2013 ◽  
Vol 671-674 ◽  
pp. 69-75
Author(s):  
Ai Jun Yao ◽  
Chao Mei ◽  
Huan Fang Chen
Keyword(s):  
Numerical Simulation ◽  
Surface Deformation ◽  
Ground Surface ◽  
Side Wall ◽  
Monitoring Data ◽  
Retaining Structure ◽  
Site Monitoring ◽  
Excavation Process ◽  
Ground Surface Settlement ◽  
3D Software

Base on the shaft construction of a subway station in Changchun, make a detailed analysis of the site monitoring data of the retaining structure and the ground surface settlement against the excavation process of the inverted side wall shaft. By using the FLAC-3D software of finite difference, the numerical simulation are conducted, thus, make a comparison with the site monitoring data, and summarize the deformation characteristics of the retaining structure and the surface deformation of the inverted side wall shaft during the excavation. Results show that the support of the inverted side wall shaft which adopting alternation excavation and supporting while excavating has good stability, and the monitoring result is close to the numerical simulation’s, which provides the basis for the success of the engineering.The research results can be references for other similar designs and constructions.

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.

scholarly journals Numerical Simulation of Deep Foundation Pit Construction under Complex Site Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huifen Liu ◽  
Kezeng Li ◽  
Jianqiang Wang ◽  
Chunxiang Cheng
Keyword(s):  
Numerical Simulation ◽  
Ground Surface ◽  
Reference Value ◽  
Horizontal Displacement ◽  
Deformation Monitoring ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Ground Surface Settlement ◽  
Stress And Deformation

Based on the deep foundation pit project of Laoguancun station of Wuhan rail transit line 16 and according to the engineering characteristics of the construction conditions and the site surrounding the environment, the method of combining field monitoring and finite element numerical simulation is adopted to analyze the law of stress and deformation of the deep foundation pit during excavation and support construction; it includes the horizontal displacement of the underground diaphragm wall, supporting axial force, and the ground surface settlement, which can be compared with measured data. Finally, some suggestions for monitoring and construction of the deep foundation pit in the subway station have been put forward and have certain reference value and practical guiding significance for the design and construction of similar engineering projects. The deformation monitoring of the retaining structure at the middle of the long side of the foundation pit should be strengthened during the construction process.

scholarly journals Active Earth Pressure of Limited C-φ Soil Based on Improved Soil Arching Effect

2020 ◽  
Vol 10 (9) ◽  
pp. 3243
Author(s):  
Meilin Liu ◽  
Xiangsheng Chen ◽  
Zhenzhong Hu ◽  
Shuya Liu
Keyword(s):  
Retaining Wall ◽  
Pressure Coefficient ◽  
Ground Surface ◽  
Side Wall ◽  
Earth Pressure ◽  
Active Earth Pressure ◽  
Soil Arching ◽  
Retaining Structure ◽  
Arching Effect ◽  
Soil Arching Effect

For c-φ soil formation (cohesive soil) of limited width with ground surface overload behind a deep retaining structure, a modified active earth pressure calculation model is established in this study. And three key issues are addressed through improved soil arching effect. First, the soil-wall interaction mechanism is determined by considering the soil arching effect. The slip surface of a limited soil is proved to be a double-fold line passing through the retaining wall toe and intersecting the side wall of the existing underground structure until it reaches the ground surface along the existing side wall. Second, the limited width boundary is explicated. And third, the variation in the active earth pressure from parameters of limited c-φ soil is determined. The lateral active earth pressure coefficient is nonlinear distributed based on the improved soil arching effect of the symmetric catenary curve. Furthermore, the active earth pressure distribution, the tension crack at the top of the retaining wall and the resultant force and its action point were obtained. By comparing with the existing analytical methods, such as the Rankine method, it demonstrates that the model proposed in this study is much closer to the measured and numerical results. Ignoring the influence of soil cohesion and the limited width will exponentially reduce the overall stability of the retaining structure and increase the risk of accidents.

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.

Analysis of the Ground Surface Settlement of Metro Tunnel by Using Peck Formula

2014 ◽  
Vol 1065-1069 ◽  
pp. 414-420
Author(s):  
Xiong Fei Yang ◽  
Hong Yuan ◽  
Jia Yu Wu ◽  
Hou Mei Zhang
Keyword(s):  
Surface Deformation ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Central Point ◽  
Surface Settlement ◽  
Point Method ◽  
Linear Regression Method ◽  
Tunnel Excavation ◽  
Ground Surface Settlement ◽  
Ground Surface Subsidence

Based on the peck formula, this paper has analyzed measured data of ground surface subsidence, and get the regression curve of ground surface subsidence. Expression for degree of reliability of the maximum ground surface settlement is derived analytically by using central-point method. On the basis of a certain section of tunnel of Guangzhou subway constructed by mining excavation method, linear regression method can be effectively fitting the ground surface deformation data due to tunnel excavation. The central-point method provides a new way for reliability analysis of the ground surface settlement of shield construction.

Numerical Analysis of Tunnel Excavation Method at Greatly Cross Undermine Huangzhuang Station of Beijing Subway

2011 ◽  
Vol 243-249 ◽  
pp. 5789-5793
Author(s):  
Jin Shui Xie ◽  
Ming Zhou Bai ◽  
Zhao Yi Xu ◽  
Ming Xing Xu ◽  
Zhu Shi ◽  
...  
Keyword(s):  
Numerical Calculation ◽  
Numerical Analysis ◽  
Surface Deformation ◽  
Ground Surface ◽  
Side Wall ◽  
Tunnel Construction ◽  
Tunnel Excavation ◽  
Geological Conditions ◽  
Numerical Calculation Method ◽  
Beijing Subway

Combined with the geological conditions and the project features, the selection problem of pilot tunnel construction method of Huangzhuang station is solved. Directing at the commonly used method including CD method, CRD method and double side wall pilot tunnel method, FLAC3D numerical calculation method is adapted to analysis and predict the ground surface deformation and supporting structure hand features. Through analyzing the size and law of surface settlement in this section, the feasibility and differences of these methods is concluded and analyzed. And finally an example is given.

scholarly journals Characteristics of Stress Transfer and Progressive Fracture in Overlying Strata due to Mining-Induced Disturbances

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Xiang-feng Lv ◽  
Hong-yuan Zhou ◽  
Ai-wen Wang ◽  
Chun Feng ◽  
Xiao-chun Xiao
Keyword(s):  
Numerical Simulation ◽  
Underground Mining ◽  
Ground Surface ◽  
Stress Transfer ◽  
Surface Settlement ◽  
Stress Concentrations ◽  
Tunnel Face ◽  
Working Face ◽  
Ground Surface Settlement ◽  
Overlying Strata

In this study, based on the mining of the 13210 working face in the Yima coal mine of the Gengcun village, China, a simplified mechanical model for the analysis of dynamic destabilization of the overlying strata during underground mining was constructed. The numerical simulation was used to analyze the stress patterns in the advanced abutments of the tunnel face and the characteristics of dynamic failures in the overlying strata. Furthermore, similitude experiments were conducted to study the process of stress release and deformation in the overlying strata, and to analyze the effects of overburden destabilization on the ground surface settlement. The theoretical analysis indicated that if the geometric parameters of a working face are fully determined, a stiffness ratio no greater than 1 is required for dynamic destabilization to occur. The numerical simulation results show that the stress in the overlying strata decreases with a decrease in distance from the tunnel face. The stresses in the advanced abutments initially increase with an increase in distance from the tunnel face, followed by a decrease in stress, and an eventual stabilization of the stress levels; this corresponds to the existence of a “stress build-up zone,” “stress reduction zone,” and “native rock stress zone.” In similitude experiments, it was observed that a “pseudoplastic beam” state arises after the local stresses of the overlying strata have been completely released, and the “trapezoidal” fractures begin to form at stress concentrations. If the excavation of the working face continues to progress, the area of collapse expands upward, thereby increasing the areas of the fracture and densification zones. Owing to the nonuniform settlement of the overlying strata and the continuous development of bed-separating cracks, secondary fractures will be generated on both sides of the working face, which increase the severity of the ground surface settlement.

scholarly journals Prediction of ground surface settlement induced by twin shield tunnellings in urban conditions

2021 ◽  
Vol 62 (2) ◽  
pp. 47-56
Author(s):  
Thai Ngoc Do ◽  
Truong Duc Nguyen ◽  
Keyword(s):  
Urban Areas ◽  
Surface Deformation ◽  
Ground Surface ◽  
Ground Subsidence ◽  
Analysis Model ◽  
Shield Tunneling ◽  
Construction Technique ◽  
Ground Deformations ◽  
Ground Surface Settlement ◽  
Surface Settlements

Tunneling in urban areas is growing in response to the increased needs for efficient transportation. Many urban tunnels are constructed in soft ground at shallow depths. Metro tunnels are usually constructed as twin-parallel tunnels and their adjacent constructions may lead to surface deformation, affecting the surface environment and the safety of the tunnels. Shield tunnelling is a commonly used as construction technique because it is very effective in reducing ground deformations and thus damage to urban infrastructure. The paper presents a 3D simulation of shield tunneling machines via the finite element code Abaqus and analysis model of ground surface settlements induced by a construction of twin-parallel tunnels. The results show that ground surface settlements induced by a construction of the left tunnel causes surface settlements of about 22÷24 mm and after the construction of both tunnels, it will cause ground subsidence has the greatest value of 33÷35 mm.

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