scholarly journals Difficulties in the Construction of Subway Tunnel Underpass Project and Research on Ecological Restoration Technology

2021 ◽  
Author(s):  
Yongchao Zhu, Pengbo Cui, Hongshuo Sun
Keyword(s):  
Bending Moment ◽  
Internal Force ◽  
Analysis Model ◽  
Subway Tunnel ◽  
Step Method ◽  
Tunnel Support ◽  
Organization And Management ◽  
Construction Methods ◽  
Geological Conditions ◽  
Dynamic Numerical Simulation

Subway construction is a high-risk construction project, because there are many uncertain factors such as Undercrossing urban hinterland and geological conditions, which lead to the difficulty of organization and management and frequent safety accidents. Therefore, there is an urgent need for effective safety risk analysis model and risk management means to prevent accidents. Aiming at the mechanical problems of surrounding rock and supporting structure of subway tunnel under different construction methods, the dynamic numerical simulation of three pilot tunnel method and upper and lower step method is carried out by using finite element method. The transformation relationship between stress field and displacement field of subway tunnel under different construction procedures is established, and the two construction methods are compared. The test results show that the internal force, axial force and bending moment model of the subway tunnel support structure system established in this paper has a certain guiding significance for the design and safe construction of the subway tunnel.

Random Seismic Response Analysis of Leaning-Type Arch Bridge

2011 ◽  
Vol 378-379 ◽  
pp. 332-336
Author(s):  
Yong He Li ◽  
Ai Rong Liu ◽  
Qi Cai Yu ◽  
Pan Tang ◽  
Fang Jie Cheng
Keyword(s):  
Bending Moment ◽  
Internal Force ◽  
Response Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Arch Bridge ◽  
Space Truss ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Impact

With an example of steel pipe concrete leaning-type arch bridge, space truss system Finite Element Analysis model is constructed using the Ruiz-Penzien random seismic vibration power spectrum model. The impact of inclined arch rib angle and the number of cross brace between main and stable arch ribs on the seismic internal force response under lateral random seismic excitation is also studied in this research. Research finding shows, the in-plane bending moment of main arch rib gradually increases with increasing stable arch rib angle and cross brace, whereas the out-of-plane bending moment and axial force display a decreasing trend. In general, this indicates that increasing stable arch rib angle and number of cross brace improves the lateral aseismatic performance of leaning-type arch bridge.

Analysis of Mechanical Behavior of Subway Tunnel Constructed by Cover and Cut Reverse Method

2012 ◽  
Vol 446-449 ◽  
pp. 3623-3627
Author(s):  
Tie Cheng Wang ◽  
Yang Gao ◽  
Hai Long Zhao
Keyword(s):  
Bending Moment ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Surrounding Rock ◽  
Diaphragm Wall ◽  
Tunnel Construction ◽  
Construction Process ◽  
Subway Tunnel ◽  
Diaphragm Walls ◽  
Reverse Method

In the paper, not only the internal force and displacement of structure during subway tunnel construction with cover and cut reverse method, but also the displacement field and stress field of surrounding rock are analysed. From the numerical calculation it is shown that the bending moment of diaphragm wall is affected seriously by the distribution and value of the stiffness of horizontal support; the excavation phase of the soil of the second floor underground is the key phase of the construction process because the internal force of structure has large increase; the value of surface settlement, horizontal displacement of diaphragm wall, differential settlement between middle pillar and diaphragm walls all meet the requirements, so the construction is safe and the surrounding buildings are affected slightly.

GA-Optimization on Weiling Space of Steel Sheet Piles Construction

2012 ◽  
Vol 204-208 ◽  
pp. 28-32
Author(s):  
Rui Jie Zheng ◽  
Su Fu ◽  
Jin Guo
Keyword(s):  
Deep Sea ◽  
Strong Influence ◽  
Steel Sheet ◽  
Bending Moment ◽  
Internal Force ◽  
Optimization Models ◽  
Objective Functions ◽  
Advantages And Disadvantages ◽  
Construction Methods ◽  
Current Water

The advantages and disadvantages of two construction methods of steel sheet piles cofferdam are introduced and analyzed in the presented work, the analysis result of three representative models indicate that support setting plays an important role and has a strong influence on the internal force of steel sheet piles. Using genetic algorithm (GA) and matlab finite element and user-defined objective functions, two optimization models are proposed for traditional and inverse construction method. The work of this paper demonstrates that using reasonable support space can effective reduce the maximum bending moment of the steel sheet piles, it means that steel sheet piles can break current water depth limitation and application in deep-sea construction.

scholarly journals Design of Flying-Bird Type Cable Stayed Arch Bridge with Three-Leaf Rose Shaped CFST Arch Rib

2021 ◽  
Vol 293 ◽  
pp. 02010
Author(s):  
Weisheng Wang ◽  
Jilin Wang
Keyword(s):  
Bending Moment ◽  
Internal Force ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Arch Bridge ◽  
Cable Structure ◽  
Stay Cables ◽  
Engineering Parameters ◽  
Negative Bending

According to the geometric figure of three-leaf rose curve, this paper puts forward a flying-bird type cable-stayed arch bridge with three-leaf rose curve shaped CFST arch rib, which has beautiful appearance and one bridge leads to three banks.The space cables are set between the three-leaf rose linear space arch ribs to resist negative bending moment, and the tie cables are set between the arch feet to resist positive bending moment. On the inclined pylon at the tail of the flying-bird type cable-stayed arch bridge, the stay-cables are arranged to balance the arch thrust, and the suspension-cables are arranged on the three leaf rose linear spatial arch ribs to hang the three fork bridge deck.The flying-bird type cable-stayed arch bridge with three-leaf rose linear CFST arch rib adopts spatial cable structure system, which has good structural stability.Combined with the actual project, the engineering parameters are designed, the Midas finite element analysis model is established, the internal force analysis and modal analysis are carried out, and the rationality of flying-bird type cable-stayed arch bridge with three-leaf rose linear CFST arch rib is verified.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

Verification of an Advanced BHA Analysis Model With Downhole Bending Moment Measurements

2005 ◽  
Author(s):  
Michael Neubert ◽  
Gerald Heisig ◽  
Ingo Forstner ◽  
Fadi Mounzer
Keyword(s):  
Bending Moment ◽  
Analysis Model

On Numerical Simulation of the Stepped Soil-Nail Wall

2013 ◽  
Vol 353-356 ◽  
pp. 692-695
Author(s):  
Chang Zhi Zhu ◽  
Quan Chen Gao
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Internal Force ◽  
Numerical Results ◽  
Analysis Model ◽  
Foundation Pit ◽  
Soil Nails ◽  
Soil Nail ◽  
Soil Nail Wall ◽  
Design And Construction

Based on an Engineering Example which was supported by the stepped soil-nail wall, a numerical analysis model was established by FLAC3D,and the process of the excavation and supporting was simulated, and the numerical results of the soil nails internal force and foundation pit deformation were obtained. The simulated result was consistent with the measured results. It shows that the method of FLAC3D numerical analysis can be used to the numerical analysis of foundation pit excavation and supporting, and it will provide the basis for the design and construction of practice project.

scholarly journals Analysis of Ground Deformation Caused by Subway Tunnel Excavation in Kunming

2021 ◽  
Vol 236 ◽  
pp. 03029
Author(s):  
Ping Wei ◽  
Liuchuang Wei
Keyword(s):  
Ground Deformation ◽  
Horizontal Displacement ◽  
Subway Tunnel ◽  
Buried Pipelines ◽  
Tunnel Excavation ◽  
Protection Measures ◽  
Geological Conditions ◽  
Soil Stress ◽  
Foundation Deformation ◽  
At Home

Research at home and abroad shows that subway excavation often causes soil stress loss, resulting in settlement deformation and horizontal displacement of stratum. Therefore, combined with the special engineering geological conditions in Kunming area, the foundation deformation caused by subway excavation is studied, so as to provide an important foundation for proposing the protection measures of surrounding buildings and buried pipelines and promoting the construction of subway.

scholarly journals Numerical Simulation of Dynamic Response and Evaluation of Flexural Damage of RC Columns under Horizontal Impact Load

2021 ◽  
Vol 11 (23) ◽  
pp. 11223
Author(s):  
Bin Hu ◽  
Jian Cai ◽  
Jiabin Ye
Keyword(s):  
Static Load ◽  
Impact Load ◽  
Bending Moment ◽  
Internal Force ◽  
Displacement Curve ◽  
Fe Model ◽  
Damage State ◽  
Rc Columns ◽  
Equivalent Static Load ◽  
The Impact

By using the ABAQUS finite element (FE) model, which has been verified by experiments, the deformation and internal force changes of RC columns during the impact process are investigated, and a parametric analysis is conducted under different impact kinetic energies Ek. According to the development path of the bottom bending moment-column top displacement curve under impact, the member is in a slight damage state when the curve rebounds before reaching the peak and in a moderate or severe damage state when the curve exceeds the peak, in which case the specific damage state of the member needs to be determined by examining whether there is a secondary descending stage in the curve. Accordingly, a qualitative method for evaluating the bending failure of RC column members under impact is obtained. In addition, the damage state of RC columns under impact can also be quantitatively evaluated by the ratio of the equivalent static load Feq and the ultimate static load-bearing capacity Fsu.

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