Slope Strengthening by Using a Grid Beam System

2012 ◽  
Vol 204-208 ◽  
pp. 842-847
Author(s):  
Fan Yang ◽  
Bo Chen ◽  
Chun Fang Song ◽  
Peng Yun Li
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Bending Moments ◽  
Beam System ◽  
Excavation Process ◽  
Geological Conditions ◽  
Commercial Package ◽  
Vertical Beam ◽  
The Stability ◽  
Dimensional Element

The evaluation of slope strengthening by using a grid beam system is carried out in this study by using a real slope existed in China is taken as the example to investigate the effects of the strengthening approach. The geological conditions of the example slope are introduced at first. The three dimensional element model of the slope is constructed with the aiding of the commercial package FLAC3D. The excavation process is simulated to obtain the stress distribution and displacement status. The slope performances without and with strengthening are numerical investigated and compared. The different bending moments of vertical beam of the frame and foundation pressure of slope reinforced with binding bolts, pre-pressed anchors and stress dispersion cables are computed. The made observations indicate that the stability of the slope has been obviously improved by applying the strengthening. The approach utilized in this study can also be adopted in the slope strengthening on the other sites.

scholarly journals Modeling inflatable fabric with undevelopable surfaces by motion folding method

2019 ◽  
Vol 14 ◽  
pp. 155892501988640
Author(s):  
Xiao-Shun Zhao ◽  
He Jia ◽  
Zhihong Sun ◽  
Li Yu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Study ◽  
Technical Problem ◽  
Three Dimensional ◽  
Element Model ◽  
Model Errors ◽  
Folding Model ◽  
Study Results ◽  
The Stability

At present, most space inflatable structures are composed of flexible inflatable fabrics with complex undevelopable surfaces. It is difficult to establish a multi-dimensional folding model for this type of structure. To solve this key technical problem, the motion folding method is proposed in this study. First, a finite element model with an original three-dimensional surface was flattened with a fluid structure interaction algorithm. Second, the flattened surface was folded based on the prescribed motion of the node groups, and the final folding model was obtained. The fold modeling process of this methodology was consistent with the actual folding processes. Because the mapping relationship between the original finite element model and the final folding model was unchanged, the initial stress was used to modify the model errors during folding process of motion folding method. The folding model of an inflatable aerodynamic decelerator, which could not be established using existing folding methods, was established by using motion folding method. The folding model of the inflatable aerodynamic decelerator showed that the motion folding method could achieve multi-dimensional folding and a high spatial compression rate. The stability and regularity of the inflatable aerodynamic decelerator numerical inflation process and the consistency of the inflated and design shapes indicated the reliability, applicability, and feasibility of the motion folding method. The study results could provide a reference for modeling complex inflatable fabrics and promote the numerical study of inflatable fabrics.

BIOMECHANICAL STABILITY OF THE CERVICAL SPINE AFTER UNCINATE PROCESS RESECTION: A FINITE ELEMENT ANALYSIS

2015 ◽  
Vol 15 (06) ◽  
pp. 1540049 ◽  
Author(s):  
XUEFENG BO ◽  
XI MEI ◽  
HUI WANG ◽  
WEIDA WANG ◽  
ZAN CHEN ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Uncinate Process ◽  
Total Deformation ◽  
Maximum Equivalent Stress ◽  
Left And Right ◽  
The Stability

When performing anterolateral foraminotomy for the treatment of cervical spondylotic radiculopathy, the extent of uncinate process resection affects the stability of the cervical spine. The aim of this study was to determine the stability of the cervical spine after resection of various amounts of the uncinate process. Based on computed tomography (CT) scans of an adult male volunteer, a three-dimensional geometric model of the cervical spine (C4-C6) was established using Mimics 13.1, SolidWorks 2012, and ANSYS 15.0 software packages. Next, the mechanical parameters of the tissues were assigned according to their different material characteristics. Using the tetrahedral mesh method, a three-dimensional finite element model of the cervical spine was then established. In modeling uncinated process resection, two excision protocols were compared. The first excision protocol, protocol A, mimicked the extent of resection used in current clinical surgical practice. The second excision protocol, protocol B, employed an optimal resection extent as predicted by the finite element model. Protocols A and B were then used to resect the left uncinate process of the C5 vertebra to either 50% or 60% of the total height of the uncinate process. The stability of the cervical spine was assessed by evaluating values of deformation and maximum equivalent stress during extension, flexion, lateral bending, and rotation. After protocol A resection, the total deformation was increased as was the maximum equivalent stress during left and right rotation. After protocol B resection, the total deformation was little changed and the maximum equivalent stress was visibly decreased during left and right rotation. As evidenced by these results, protocol B resection had relatively little effect on the stability of the cervical spine, suggesting that resection utilizing the limits proposed in protocol B appears to better maintain the stability of the cervical spine when compared with current clinical surgical practice as replicated in protocol A.

Stability Analysis about the Impact of Soft Rock to the Underground Cavern Group

2013 ◽  
Vol 706-708 ◽  
pp. 560-564
Author(s):  
Yi Huan Zhu ◽  
Guo Jian Shao ◽  
Zhi Gao Dong
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Soft Rock ◽  
Element Model ◽  
Underground Excavation ◽  
Power Station ◽  
Excavation Process ◽  
The Stability ◽  
The Impact

Soft rock is frequently encountered in underground excavation process. It is difficult to excavate and support in soft rock mass which has low strength, large deformation and needs much time to be out of shape but little time to be self-stabilized. Based on a large underground power station, finite element model analysis was carried out to simulate the excavation process and the results of displacement, stress and plasticity area were compared between supported and unsupported conditions to evaluate the stability of the rock mass.

Different Geological Conditions Affect the Results of Low Strain Integrity Testing of Piles

2011 ◽  
Vol 94-96 ◽  
pp. 692-696
Author(s):  
Zhi Qiang Zhang ◽  
Nan Gai Yi
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
Element Model ◽  
Time Curve ◽  
3 Dimensional ◽  
Geological Conditions ◽  
Dimensional Finite Element ◽  
The One ◽  
Three Dimensional Finite Element ◽  
Dimensional Wave

Low strain ingtegrity testing of pile is based on the one-dimensional wave theory.However, the pulse wave produced by hammer is actually 3-dimensional wave , whose propogation could be affected by the pile sides with different geological conditions. The effect is more obvious when the geological conditions of the pile sides become more complex. This test established three-dimensional finite element model which has fixed pile bottom and different geological conditions by applying ANSYS/LS-DYNA dynamic analysis method. The test simulated nine different boundary conditions of the pile sides. The results were divided into four groups to compare. And the velocity-time curve of the particle in different conditions was obtained. Through analyzing the simulation data, the conclusion that the stress wave is affected by the boundary conditions of the pile sides could be made.

scholarly journals Effects of different processes of tunneling on displacements soil using 3D Finite Element Method

2021 ◽  
Vol 16 (2) ◽  
pp. 203-217
Author(s):  
Nawel Bousbia
Keyword(s):  
Three Dimensional ◽  
Urban Site ◽  
Tunnel Excavation ◽  
Excavation Process ◽  
Tunneling Method ◽  
The Stability ◽  
Full Face ◽  
Ground Stability ◽  
3D Finite Element Method ◽  
Underground Constructions

Abstract The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling. The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method. The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation. The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.

Structural Design and Analysis of Aluminum Dome for Caofeidian Coal Storage

2016 ◽  
Vol 710 ◽  
pp. 396-401 ◽  
Author(s):  
Ze Chao Zhang ◽  
Hong Bo Liu ◽  
Xiao Dun Wang ◽  
Xiang Yu Yan ◽  
Jing Hai Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Aluminum Alloys ◽  
Three Dimensional ◽  
Single Layer ◽  
Element Model ◽  
Internal Force ◽  
Structural Deformation ◽  
Mode Analysis ◽  
Finite Element Software ◽  
The Stability

The upper part of Caofeidian coal storage was approximately hemispherical aluminum shell, covered with aluminum alloys plate. The capsule was made of aluminum alloys material, and its span was 125 meters. In the design, according to TEMCOR joint, we used the finite element software MIDAS to build the accurate geometry models and calculation models of aluminum alloys single layer latticed dome structures. By the combination of constant loads, live loads, snow load, wind load, temperature effect and other working conditions, we summarized the consumption of aluminum of the structures, and studied the structural internal force, structural deformation and structural stiffness. In addition, the X and Y two different direction seismic dynamic load was applied to the structure. The structural seismic performance under two kinds of modes were studied through the structure mode analysis of the vibration frequency. The vierendeel dome and single layer dome were controlled by the stability. ANSYS three-dimensional frame element model were set up, and the eigenvalue buckling analysis was carried out. By the geometrical nonlinear finite element method, combining with initial imperfections and material nonlinear, we found out the stability coefficient and the weak parts of the structure.

A Finite Element Investigation into the Effects of Head Size and Trunnion Design on the Micromotion at the Head-Neck Interface in THR

2014 ◽  
Vol 553 ◽  
pp. 287-292
Author(s):  
W. Theodore ◽  
J. Pierrepont ◽  
Q. Li ◽  
B. Miles
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Case Reports ◽  
Three Dimensional ◽  
Femoral Stem ◽  
Element Model ◽  
Head Size ◽  
Metal Head ◽  
The Stability ◽  
Head Neck

The modularity of femoral head and femoral stem provides many benefits to surgeons. However, case-reports have shown failure in large head Metal-on-Metal hip replacement due to trunnionosis. The exact causes of trunnionosis are not yet identified but the additional interface at the modular joint seems to be a contributing factor. In this study, a three dimensional non-linear finite element model was created to analyse the effects of head size and trunnion design on the micromotion at the head-neck interface. Four different metal head sizes and two trunnions designs and materials were used in the model. The femoral heads were assembled onto the trunnions with 7kN axial force and one cycle of gait load was applied to the head after assembly. The study showed that the micromotion was substantially increased in femoral head larger than 36mm. Trunnions material has greater effect on micromotion than trunnion design, particularly with the larger head sizes. The stability at the modular junction is important. Our findings suggest that there is a limit of assembly force to maintain enough stability on the joint; beyond this limit; the maximum micromotion will not be affected.

Closure of a Nuclear Waste Repository Deeply Imbedded in a Stratified Salt Bed

1994 ◽  
Vol 116 (4) ◽  
pp. 567-573 ◽  
Author(s):  
Wei Xu ◽  
Joseph Genin
Keyword(s):  
Triaxial Compression ◽  
Three Dimensional ◽  
Element Model ◽  
Nuclear Waste Repository ◽  
Relaxation Functions ◽  
Dimensional Finite Element ◽  
Set Up ◽  
The Stability ◽  
Three Dimensional Finite Element

The Waste Isolation Pilot Plant (WIPP) is a repository vault, mined deep into a salt strata. It eventually closes in on itself, encapsulating its contents. At room temperature salt may be regarded as a linear, isotropic, viscoelastic material. In this study, using triaxial compression test results on salt, we determine the relaxation functions and set up the boundary value problem for the encapsulation mechanism of a salt vault. Closure of the repository as a function of time is determined using a three-dimensional finite element model. The Tresca failure criterion is used to predict the stability of the repository. Finally, the study is validated by comparing our results to in-situ measured data.

scholarly journals Stope Stability Assessment and Effect of Horizontal to Vertical Stress Ratio on the Yielding and Relaxation Zones Around Underground Open Stopes Using Empirical and Finite Element Methods

2017 ◽  
Vol 62 (3) ◽  
pp. 653-669 ◽  
Author(s):  
Mohammadali Sepehri ◽  
Derek Apel ◽  
Wei Liu
Keyword(s):  
Finite Element ◽  
Numerical Methods ◽  
Stress Ratio ◽  
Three Dimensional ◽  
Element Model ◽  
Underground Mine ◽  
Graph Method ◽  
The Stability ◽  
Stability Graph ◽  
The Impact

AbstractPredicting the stability of open stopes can be a challenging task for underground mine engineers. For decades, the stability graph method has been used as the first step of open stope design around the world. However, there are some shortcomings with this method. For instance, the stability graph method does not account for the relaxation zones around the stopes. Another limitation of the stability graph is that this method cannot to be used to evaluate the stability of the stopes with high walls made of backfill materials. However, there are several analytical and numerical methods that can be used to overcome these limitations. In this study, both empirical and numerical methods have been used to assess the stability of an open stope located between mine levels N9225 and N9250 at Diavik diamond underground mine. It was shown that the numerical methods can be used as complementary methods along with other analytical and empirical methods to assess the stability of open stopes. A three dimensional elastoplastic finite element model was constructed using Abaqus software. In this paper a sensitivity analysis was performed to investigate the impact of the stress ratio “k” on the extent of the yielding and relaxation zones around the hangingwall and footwall of the understudy stope.

Numerical Simulation of Excavation of Abutment Slope at Left Bank in Dagangshan Hydropower Station

2012 ◽  
Vol 238 ◽  
pp. 313-316
Author(s):  
Kun Yang ◽  
Zhi Chao Ma ◽  
Hao Han
Keyword(s):  
Element Model ◽  
Hydropower Station ◽  
Left Bank ◽  
Geological Conditions ◽  
Potential Failure ◽  
Deformation Stress ◽  
The Stability ◽  
Dagangshan Hydropower Station ◽  
Failure Location ◽  
The Finite Element Model

The abutment slope at left bank in Dagangshan hydropower station has complex geological conditions with deep fractures, developed faults and unloading crack. The excavation will influence the stability of the slope. To evaluate the slope stability, the finite element model of this abutment slope was built in this paper to study the deformation, stress and plastic zone distribution of the slope during the excavation. The potential failure location of the slope is forecasted, some suggestions are proposed to be helpful to keep the stability of the slope.

Sign in / Sign up

Export Citation Format

Share Document