The Numerical Simulation Analysis of Excavation Process of Loess Tunnel

2011 ◽  
Vol 383-390 ◽  
pp. 6594-6600 ◽  
Author(s):  
Jian Guo ◽  
Qi Cai Wang
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Internal Force ◽  
Design Parameters ◽  
Construction Process ◽  
The Finite Element Method ◽  
Excavation Process ◽  
Internal Forces ◽  
The Stability ◽  
Method Construction

The bench method dynamic construction process of Xin Baotashan tunnel which located in the grade IV surrounding rock is simulated by using the finite element method. The variation of displacement and stress field of the surrounding rocks and the internal force of the lining structures during every excavation step is calculated. The state of the surrounding rocks can be predicted by the numerical simulation results, and the construction plan and construction sequences can be guided by the analysis results. At the same time the reasonability and feasibility of the design parameters can be judged by analyzing the internal forces of the lining structures. Analysis and experimental results showed that the stability of the surrounding rocks is good by using the bench method construction to the IV grade surrounding rocks and the design parameters of the lining structures are feasible.

Construction Analysis of the Chimney of Solar Thermal Power Station

2013 ◽  
Vol 283 ◽  
pp. 41-46
Author(s):  
Shao Wen Fang ◽  
Xing Fei Yuan
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Load Condition ◽  
Initial Imperfection ◽  
Internal Force ◽  
Construction Process ◽  
Buckling Mode ◽  
A Value ◽  
Gravity Load ◽  
The Stability

A 100MW solar chimney is high as one thousand meters, belonging to ultra-high-rise structure. Considering the complicated load condition, the large scale and long period of construction process, construction analysis is important to the structure. Using element birth and death technology in ANSYS, the whole construction process is simulated in this paper. Numerical results indicate that the deformation and internal force of the structure change a lot during the construction process. Great differences exist in property and magnitude between construction status and design status. To investigate the stability of the structure under wind and gravity load, the first eigen buckling mode with a value of L/300 and construction deformation are considered as initial imperfection respectively. The results show the ultimate bearing capacity of the structure considering construction deformation is lower than that considering the first-order initial imperfection.

The Research of the Relative Rigid Effect in the Numerical Simulation of the Steel Plate Reinforced Concrete Coupling Beams

2014 ◽  
Vol 638-640 ◽  
pp. 283-286
Author(s):  
Li Song ◽  
Dong Chen ◽  
Bao Lei Li
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Steel Plate ◽  
Simulation Analysis ◽  
Great Influence ◽  
Shear Walls ◽  
Internal Force ◽  
Coupling Beams ◽  
Loading Mode ◽  
Deformation Properties

The coupling beam work as an important component in coupled shear walls, the strength,stiffness and deformation properties of which have great influence on the seismic performance of shear walls, the steel plate reinforced concrete coupling beams have the advantages as follows: simplify the constructional details, make the construction convenient and reliable performance [1][2]. The numerical simulation model in this paper is a coupled shear wall connected by steel plate reinforced concrete coupling beams in reference [3], and the loading mode is the same as the reference [4] . The relative stiffness effect was explored by study the internal force and displacement of the model with changing the stiffness of the coupling beams and the shear walls while the span-depth ratio is stable .The study will provide a reference for the numerical simulation of the finite element simulation analysis of the coupling beams and the steel reinforced concrete structures.

FLAC3D Numerical Simulation Study on Deformation of Subgrade Construction Process

2011 ◽  
Vol 90-93 ◽  
pp. 466-470
Author(s):  
Ya Ni Lu ◽  
Gai Wei Li
Keyword(s):  
Numerical Simulation ◽  
Elastic Modulus ◽  
Simulation Study ◽  
Simulation Analysis ◽  
Lateral Displacement ◽  
Unit Weight ◽  
Deformation Characteristics ◽  
Construction Process ◽  
Main Research ◽  
Road Slope

Numerical simulation analysis of the deformation characteristics in the construction process of subgrade are conducted. Based on the different filling unit weight and roadbed elastic modulus conditions, the main research is that vertical settlement of roadbed center and the horizontal lateral displacement of road slope toe change with the increase of the depth of filling. It is believed that the lightweight filling should be selected or the roadbed elastic modulus will be enhanced as much as possible under the condition that satisfies various standard, which can improve the settlement deformation of highway.

Rotor Dynamic Analysis of an Eccentric Hydropower Generator With Damper Winding for Reactive Load

2007 ◽  
Vol 74 (6) ◽  
pp. 1178-1186 ◽  
Author(s):  
Martin Karlsson ◽  
Jan-Olov Aidanpää ◽  
Richard Perers ◽  
Mats Leijon
Keyword(s):  
Degrees Of Freedom ◽  
Reactive Power ◽  
Tangential Component ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Unbalanced Magnetic Pull ◽  
Hydroelectric Generator ◽  
Electromagnetic Models ◽  
The Stability ◽  
Damper Winding

Asymmetry in the magnetic circuit, around the air gap circumference, in a hydroelectric generator will give rise to a unbalanced magnetic pull. In this paper, a hydropower rotor system is modeled and the influence of electro-mechanical forces due to overexcitation is analyzed. The active power has been kept constant and the rotor excitation has been changed in order to vary the output of reactive power. The electromagnetic field is solved with the finite element method. Two electromagnetic models are compared: one with and one without damper winding. The mechanical model of the generator consists of a four degrees of freedom rigid disk connected to an elastic shaft supported by two bearings with linear properties. It has been found that the unbalanced magnetic pull slightly increases for reactive loads resulting in a decrease of natural frequencies and an increase of unbalance response. When the damper winding is included, the magnetic pull will decrease compared to the model without damper winding, and the pull force has two components: one radial and one tangential. The tangential component can influence the stability of the mechanical system for a range of design parameters.

scholarly journals Research on Construction Methods for Ultralarge Y-Shaped Tunnel Sections

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shiding Cao ◽  
Yongli Xie ◽  
Wei Tang ◽  
Wei Wang ◽  
Qianru Zhou ◽  
...  
Keyword(s):  
Stability Criterion ◽  
Abrupt Change ◽  
Internal Force ◽  
Special Method ◽  
Large Section ◽  
Large Span ◽  
Construction Methods ◽  
Excavation Process ◽  
Clear Distance ◽  
The Stability

Many problems are encountered in the construction of bifurcated tunnels due the abrupt change in section, small clear distance, and large section. Progress in the direction of tunnel construction is limited by the large-span section; therefore, a special method of construction that involves constructing a guiding tunnel first followed by reverse excavation was adopted to construct the large-span bifurcation section of the Liantang tunnel of Shenzhen Eastern Transit Expressway in China. The stability criterion of the surrounding rock of the middle wall in the section of multiple arch and small clear distance is studied by theoretical analysis, and the internal stress and corresponding ultimate strength of the middle wall under different buried depths and widths of the middle wall are calculated by the stability criterion. In this study, 3D finite-difference software was used to simulate the excavation process under forward and reverse excavation conditions. The results show that the displacement field and internal force field distribution are similar for both excavation methods, and the tunneling first and reverse excavation construction method is safe and reliable.

scholarly journals Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction

2019 ◽  
Vol 9 (11) ◽  
pp. 2213 ◽  
Author(s):  
Su-Won Son ◽  
Minsu Seo ◽  
Jong-Chul Im ◽  
Jae-Won Yoo
Keyword(s):  
Numerical Analysis ◽  
Maximum Stress ◽  
Lateral Displacement ◽  
Retaining Wall ◽  
Field Tests ◽  
Front Wall ◽  
Construction Process ◽  
Construction Methods ◽  
Excavation Process ◽  
The Stability

Retaining walls are generally used for temporary installations during the excavation process of a construction project. They are also utilized to construct embankments in order to extend a railway facility. In this case, a retaining wall is installed during the construction process and contributes to the resistance of large amounts of stress, including the railway load. However, it is generally difficult to retain walls to maintain their stability. Therefore, alternative construction methods, such as the use of an inclined earth-retaining wall, have been utilized to suppress the lateral displacement. The stability is verified in advance through field tests; however, the maximum stress acting on the railway is thought to be the concentrated railway load. In this study, a two-dimensional numerical analysis was conducted by changing the railway load to a dynamic load. The analysis was applied according to the number of H-piles of the same length (10 m) when only the front wall was installed and when a back support was also applied. It was determined that the lateral displacement of the latter case is smaller than that of the former, whereas the resistance to dynamic loading of the former case is greater.

scholarly journals Mitigation through seepage reduction in dams

2020 ◽  
Vol 156 ◽  
pp. 01006
Author(s):  
Novy Haryati ◽  
Abdul Hakam
Keyword(s):  
Numerical Simulation ◽  
Field Tests ◽  
Soil Parameters ◽  
The Finite Element Method ◽  
Seepage Analysis ◽  
Variation Of Parameters ◽  
Study Results ◽  
The Stability ◽  
North Sumatra ◽  
Good Research

There are many landslide and damages have occurred at dams due to the seepage. In addition, dam works often took inattention of the underneath soil parameters. This careless works resulted in failure of the dam structure as well as landslides. Based on this reason, a good research to be applied to dams is needed. Further, the potential landslides can be avoided. In this study an analysis of seepage analysis at the bottom of the dam is carried out. The landslide analysis is done by varying the parameter to build up the seepage. The case studies analyzed is taken at the seepage that occurred in Sei Wampu Dam located in North Sumatra. Soil data are obtained from the field tests which have been carried out in the previous work. The numerical simulation using the finite element method is gained to conduct the analysis. During the analyses, the variation of parameters obtained from the seepage calculation was recorded. The obtained seepage parameters that affect the stability of dams are then elaborated. The study results can be used for the mitigation efforts at the dams that have the potential for landslides.

scholarly journals Optimal grasp planning for a dexterous robotic hand using the volume of a generalized force ellipsoid during accepted flattening

2017 ◽  
Vol 14 (1) ◽  
pp. 172988141668713 ◽  
Author(s):  
Peng Jia ◽  
Wei li Li ◽  
Gang Wang ◽  
Song Yu Li
Keyword(s):  
Simulation Analysis ◽  
Internal Force ◽  
Planning Method ◽  
Robotic Hand ◽  
Grasp Planning ◽  
Joint Torques ◽  
Contact Points ◽  
Generalized Force ◽  
Internal Forces ◽  
Dexterous Hand

A grasp planning method based on the volume and flattening of a generalized force ellipsoid is proposed to improve the grasping ability of a dexterous robotic hand. First, according to the general solution of joint torques for a dexterous robotic hand, a grasping indicator for the dexterous hand—the maximum volume of a generalized external force ellipsoid and the minimum volume of a generalized contact internal force ellipsoid during accepted flattening—is proposed. Second, an optimal grasp planning method based on a task is established using the grasping indicator as an objective function. Finally, a simulation analysis and grasping experiment are performed. Results show that when the grasping experiment is conducted with the grasping configuration and positions of contact points optimized using the proposed grasping indicator, the root-mean-square values of the joint torques and contact internal forces of the dexterous hand are at a minimum. The effectiveness of the proposed grasping planning method is thus demonstrated.

scholarly journals Theoretical Research and Numerical Simulation on Water Resistance Mechanism of Textile Bag in Water Passage

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Ang Li ◽  
Yuxuan Yang ◽  
Mingcheng Zhu ◽  
Wenzhong Zhang ◽  
Bingnan Ji ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Water Resistance ◽  
Simulation Analysis ◽  
Water Pressure ◽  
Water Inrush ◽  
Deformation Characteristics ◽  
Water Blocking ◽  
The Stability ◽  
Water Passage

It is an important problem in the mine water disaster prevention and control to control the large passage moving water. Traditional grouting technology is to put coarse aggregate and fine aggregate downward first and then grouting treatment. But the aggregate and cement flow distance is long, consumption is large, cost is high, and easy to appear secondary water inrush. Centering on the technical difficulties in the rapid construction of the blocking body of the moving water passage, a water-blocking textile bag was invented. The purpose of blocking the tunnel water inrush was achieved by grouting inside the bag body, which fundamentally realized the rapid blocking of the large passage through water under the condition of moving water. However, the mechanism, water plugging law, and design parameters of water blocking roadway with textile bag are still unclear. In this paper, the slip law and stability of the textile bag in the moving water and the deformation characteristics caused by the dynamic water pressure are theoretically analyzed and simulated. Through theoretical analysis, the ultimate antihydraulic stress value of a textile bag of a certain specification is calculated, and the parameters of the textile bag that affect the stability of the bag body are also determined. Xflow was used for numerical simulation analysis to study the deformation characteristics of the textile bag under water and the law of water barrier. The simulation analysis focuses on the water resistance effect and flow field distribution characteristics of the textile bag in the water passage under the condition of low flow rate and low pressure, as well as the stability and self-deformation characteristics of the textile bag under the condition of high flow rate and high pressure. The accuracy of the limit resistance to water pressure of the textile bag obtained from theoretical analysis is verified. The results show that the theoretical analysis is consistent with the simulation results. The textile bag can realize the fast controllable plugging of the large water passage of moving water within the limit of the antihydraulic stress.

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