scholarly journals Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

2021 ◽  
Vol 11 (16) ◽  
pp. 7577
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Wei Wang ◽  
Xiancong Meng ◽  
Hong Guo
Keyword(s):  
Dynamic Characteristics ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Decisive Factor ◽  
Cross River ◽  
Static Responses ◽  
Train Vibration ◽  
Twin Tunnels

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

Finite-Infinite Element Dynamic Analysis of Pile-Soil-Structure System Considering the Change of Groundwater Level

2011 ◽  
Vol 250-253 ◽  
pp. 2291-2295
Author(s):  
Wei Hu ◽  
Guang Fan Li ◽  
Juan Du
Keyword(s):  
Dynamic Characteristics ◽  
Groundwater Level ◽  
Soil Structure ◽  
Horizontal Displacement ◽  
Element Model ◽  
Geological Condition ◽  
Shearing Stress ◽  
Structural Dynamic ◽  
Structure System ◽  
Infinite Element

The rise of groundwater level can reduce soil’s effective stress and destroy it’s structure. As a result, the dynamic characteristics of pile-soil-structure system will be changed remarkably. In this paper, a structural dynamic model was used for saturated loess, and the finite-infinite element model of pile-soil-structure system was established to study the groundwater level’s influence on the system’s dynamic characteristics, which included the distributions of pile section’s shearing stress, horizontal displacement and acceleration. The results indicated that, the height of groundwater level did not change the distribution shapes of shearing stress, horizontal acceleration, but had effect on their values. To the top section’s shearing stress and horizontal displacement, there almost had a same dividing groundwater level. When groundwater level was higher than that one, the shearing stress and horizontal displacement were increasing with the rising of groundwater level, but the regulations were just opposite when groundwater level under that height. The study also shown that, to a determinate geological condition and pile foundation, there has a dividing groundwater level, and which is also the most secure level to the pile-soil-structure system. The conclusion can give theoretic instruction for the safety evaluation of pile-soil-structure system around water area.

Finite Element Numerical Simulation Analysis on Deformation of Adjacent Building with Shallow Foundation due to Excavation

2013 ◽  
Vol 353-356 ◽  
pp. 403-406
Author(s):  
Yong Kang Yang ◽  
Xiao Yuan Li ◽  
Wu Yang ◽  
Chun Yan Feng
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Simulation Analysis ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Shallow Foundation ◽  
Foundation Pit ◽  
Adjacent Building ◽  
Finite Element Numerical Simulation

Based on deformation of adjacent building with shallow foundation of foundation pit excavation, Midas GTS is adopted to establish the finite element model. Through the numerical simulation, the maximum horizontal and vertical displacement in different conditions, Influence of different SMW pile stiffness and influence of different anchor position are analyzed. The results show that (1) horizontal deformation of SMW pile is decreased at the anchor construction; (2) compared with maximum horizontal displacement of SMW pile with 25a25b28a, the maximum horizontal displacement of SMW pile with 28b is increased by 50.9, 43.3, 11.5% respectively; (3) compared with the second anchor at 1.5, 3.5m, the horizontal displacement of adjacent building is minimal by the second anchor at 2.5m.

scholarly journals Displacement and Deformation of the First Tunnel Lining During the Second Tunnel Construction

2019 ◽  
Vol 5 (2) ◽  
pp. 332 ◽  
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Zhihua Zhang ◽  
Luqing Luo ◽  
Weichen Sun
Keyword(s):  
Water Pressure ◽  
Three Dimensional ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Tunnel Lining ◽  
Scale Model ◽  
Tunnel Construction ◽  
Soil Arching ◽  
Clear Distance ◽  
Twin Tunnels

A three-dimensional twin tunnels scale model was established utilizing the discrete element method (DEM) with PFC3D. This model aims to investigate the displacement (in horizontal and vertical directions) and deformation of the first tunnel lining in four different cases which the clear distance of twin tunnels are 5, 10, 15 and 20 m during the second tunnel construction process. The numerical results indicate that the clear distance between twin tunnels and the distance between the measurement points of the first tunnel and the excavation area of the second tunnel are two most critical factors that influence the displacement and deformation of the first tunnel lining. Meanwhile, the soil arching effect, gravity, water pressure and lateral pressure also have an impact on the behavior of the first tunnel. The maximum disturbance of horizontal and vertical displacements occurred in the time points of finishing of the second tunnel. However, the horizontal displacement of the first tunnel is much more sensitive to the vertical displacement. The first tunnel turns to the right and down in direction while having an anticlockwise rotation (φ) during the process of construction of the second tunnel. In addition, the displacement and deformation of the lining of the first tunnel are critical to monitor, and the necessary precautions should be taken to decrease the risk of craze. In conclusion, the influence of the second tunnel excavation on the first tunnel lining could be neglected when their distance is more than 15 m.

Study of Grouting Reinforcement to Disturbance Soft SOIL Caused by Large Diameter Slurry Shield Construction

2013 ◽  
Vol 790 ◽  
pp. 401-404
Author(s):  
Jian Ming Zhu ◽  
Hai Feng Cheng
Keyword(s):  
Finite Element ◽  
Soft Soil ◽  
Large Diameter ◽  
Soil Layer ◽  
Element Model ◽  
Vertical Displacement ◽  
Soil Disturbance ◽  
Finite Element Software ◽  
Grouting Reinforcement ◽  
Slurry Shield

Study of grouting reinforcement to disturbance soft soil caused by large diameter slurry shield construction based on Jiangyin Chengjiang West Road over the river tunnel project. First, Three-dimensional finite element model is created to use the ABAQUS finite element software, considering nonlinear deformation of soil in the numerical calculations. By numerical simulation: horizontal, vertical, vertical displacement trends are in accordance with the measured data; increase the layer E, C, φ values can effectively reduce the settlement of soft soil layer, reducing the soil disturbance. Therefore, through grouting reinforcement of upper soil can reduce soil settlement and get to the purpose of reducing the soil disturbance.

Numerical Analysis of Metro Station Construction by Large-Diameter Shield and Pile-Beam-Arch Method

2011 ◽  
Vol 368-373 ◽  
pp. 2711-2715 ◽  
Author(s):  
De Yun Ding ◽  
Xiu Ren Yang ◽  
Wei Dong Lu ◽  
Wei Ning Liu ◽  
Mei Yan ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Large Diameter ◽  
Element Model ◽  
Construction Method ◽  
Shield Tunnel ◽  
Outer Diameter ◽  
Shield Tunneling ◽  
Metro Station ◽  
Dimensional Finite Element ◽  
New Construction

In more and more complicated urban building environment, a new construction method that metro engineering is constructed by large-diameter shield and shallow mining method can be regarded as a great attempt in China. By taking the Gaojiayuan station of Beijing metro line 14 as an engineering background, the main construction steps for the platform of the metro station built by a large-size shield with an outer diameter of 10 m and the Pile-Beam-Arch (PBA) method are introduced. Based on the soil-structure interaction theory, a two-dimensional finite element model is used to simulate the shield tunneling and the platform construction by the PBA method to enlarge the shield tunnel. The ground deformation and structural stress of the platform are predicted. The numerical results can be regarded as a valuable reference for the application of the new construction method in Beijing metro line 14.

Estimation of Residual Stress in Spiral Welded Pipe: Regression and Numerical Model

2012 ◽  
Author(s):  
Abul Fazal M. Arif ◽  
Ahmad S. Al-Omari ◽  
Anwar K. Sheikh ◽  
Yagoub Al-Nassar ◽  
M. Anis
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Critical Role ◽  
Large Diameter ◽  
Element Model ◽  
Regression Equation ◽  
Field Analysis ◽  
Welding Parameters ◽  
Splitting Test ◽  
Welded Pipe

Double submerged spiral-welded pipe (SWP) is used extensively throughout the world for large-diameter pipelines. Fabrication-induced residual stresses in spiral welded pipe have received increasing attention in gas, oil and petrochemical industry. Several studies reported in the literature verify the critical role of residual stresses in the failure of these pipes. Therefore, it is important that such stresses are accounted for in safety assessment procedures such as the British R6 and BS7910. This can be done only when detailed information on the residual stress distribution in the component is known. In industry, residual stresses in spiral welded pipe are measured experimentally by means of destructive techniques known as Ring Splitting Test. In this study, statistical analysis and linear-regression modeling were used to study the effect of several structural, material and welding parameters on ring splitting test opening for spiral welded pipes. The experimental results were employed to develop an appropriate regression equation, and to predict the residual stress on the spiral welded pipes. It was found that the developed regression equation explains 36.48% of the variability in the ring opening. In the second part, a 3-D finite element model is presented to perform coupled-field analysis of the welding of spiral pipe. Using this model, temperature as well as stress fields in the region of the weld edges is predicted.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

scholarly journals Influence of rigidity of retainers on dynamic behavior of implant-supported removable partial dentures

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Toshifumi Nogawa ◽  
Masayasu Saito ◽  
Naomichi Murashima ◽  
Yoshiyuki Takayama ◽  
Atsuro Yokoyama
Keyword(s):  
Dynamic Behavior ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Denture Base ◽  
Second Molar ◽  
Mechanical Simulation ◽  
Computed Tomography Images ◽  
Significant Difference ◽  
Abutment Teeth ◽  
Distal Extension

Abstract Background Implant-supported removable partial dentures (ISRPDs) are an effective treatment for partially edentulous patients. ISRPDs improve patients’ satisfaction and oral function to a greater extent than RPDs by improving denture stability and enhancing support. However, the effect of a type of direct retainer on displacement of the abutment teeth and dentures in ISRPDs remains unclear. Therefore, we made a resin mandibular model of unilateral mandibular distal-extension partial edentulism for mechanical simulation and compared the dynamic behavior of the abutment teeth and the denture base among different tooth-borne retainers with various rigidities for RPDs and ISRPDs. Methods A resin mandibular model for mechanical simulation that had unilateral mandibular distal-extension edentulism and was missing the first molar, second molar, first premolar, and second premolar, and a denture fabricated from the patient’s computed tomography images were used. Three types of direct retainers with different connecting rigidities were evaluated. The vertical displacement of the denture base and buccal and lingual sides and the mesial displacement of the abutment teeth were measured. Results Regardless of the rigidity of the direct retainers and loading positions, the displacement of the denture bases in the ISRPDs was significantly smaller than that in the RPDs (P < 0.001). There was no significant difference in vertical displacement of the denture bases among direct retainers with various connecting rigidities in the ISRPDs. Conversely, horizontal displacement of the abutment teeth in both the RPDs and ISRPDs tended to be larger with the cone crown telescope, which has high rigidity, than with the cast cingulum rest and wire clasp, which have much lower rigidities. Conclusion Our results suggested that cast cingulum rest and wire clasps as direct retainers are appropriate ISRPDs to minimize denture movement and suppress displacement of the remaining teeth in patients with unilateral mandibular distal-extension partial edentulism.

Dynamic Characteristics Analysis of Cable-Rib Tension Deployable Antenna

2016 ◽  
Author(s):  
Liu Ruiwei ◽  
Hongwei Guo ◽  
Zhang Qinghua ◽  
Rongqiang Liu ◽  
Tang Dewei
Keyword(s):  
Dynamic Characteristics ◽  
Structural Parameters ◽  
Element Model ◽  
Structure Design ◽  
Antenna Structure ◽  
Characteristics Analysis ◽  
New Type ◽  
Dynamic Characteristics Analysis ◽  
The Finite Element Model ◽  
Weight Dynamic

Balancing stiffness and weight is of substantial importance for antenna structure design. Conventional fold-rib antennas need sufficient weight to meet stiffness requirements. To address this issue, this paper proposes a new type of cable-rib tension deployable antenna that consists of six radial rib deployment mechanisms, numerous tensioned cables, and a mesh reflective surface. The primary innovation of this study is the application of numerous tensioned cables instead of metal materials to enhance the stiffness of the entire antenna while ensuring relatively less weight. Dynamic characteristics were analyzed to optimize the weight and stiffness of the antenna with the finite element model by subspace method. The first six orders of natural frequencies and corresponding vibration modes of the antenna structure are obtained. In addition, the effects of structural parameters on natural frequency are studied, and a method to improve the rigidity of the deployable antenna structure is proposed.

Dynamic Characteristic Analysis of Irregularity under Turnout by Vehicle-Turnout Rigid-Flexible Coupling Model

2014 ◽  
Vol 945-949 ◽  
pp. 591-595 ◽  
Author(s):  
Meng Chen ◽  
Yan Yun Luo ◽  
Bin Zhang
Keyword(s):  
Finite Element ◽  
Longitudinal Direction ◽  
Element Model ◽  
Vertical Displacement ◽  
Coupling Model ◽  
Interaction Force ◽  
Vertical Acceleration ◽  
Characteristic Analysis ◽  
Flexible Coupling ◽  
Multi Body

Finite element model of track in frog zone is built by vehicle-turnout system dynamics. Considering variation of rail section and elastic support, bending deformation of turnout sleeper, spacer block and sharing pad effects, the track integral rigidity distribution in longitudinal direction is calculated in the model. Vehicle-turnout rigid-flexible coupling model is built by finite element method (FEM), multi-body system (MBS) dynamics and Hertz contact theory. With the regularity solution that different stiffness is applied for rubber pad under sharing pad of different turnout sleeper zone, analysis the variation of vertical acceleration of bogie and wheelset, rail vertical displacement and wheel-rail interaction force, this paper proves that setting reasonable rubber pad stiffness is an efficient method to solve rigidity irregularity problem.

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