scholarly journals Model Test Study on the Influence of Ground Surcharges on the Deformation of Shield Tunnels

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1565
Author(s):  
Gang Wei ◽  
Shuming Zhang ◽  
Pengfei Xiang
Keyword(s):  
Model Test ◽  
Three Dimensional ◽  
Theoretical Method ◽  
Shield Tunnel ◽  
Burial Depth ◽  
Scaled Model ◽  
Test Study ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Three Dimensional Finite Element

Aiming at studying the harm caused by sudden ground loadings on existing shield tunnels, a indoor scaled model test with a geometric similarity ratio of 1:15.5 was adopted. Considering the influencing factors such as ground loading, burial depth of the shield tunnel, loading position and soil properties, tunnel convergence deformation, tunnel settlement and deep settlement of soil caused by sudden ground loadings are studied. A three-dimensional finite element simulation is carried out using the Midas software, and deep settlement of soil is calculated by a theoretical method. The purpose of this model test is to further understand the influence of ground surcharges on shield tunnel deformation. The results show that the greater the ground surcharge, the greater the settlement and vertical convergence deformation of the shield tunnel; The further away from the ground surcharge, the smaller the settlement, vertical convergence deformation and lateral convergence deformation of the tunnel. When the pile load size is constant, the greater the burial depth of the tunnel, the smaller the vertical convergence deformation and settlement of the tunnel; the maximum value of deep settlement of the soil always remains at the closest point to the ground surcharge; compared with the use of dry sand, the vertical convergence deformation and settlement of the tunnel are significantly reduced when using wet sand. Both the theoretical calculation results and the numerical simulation results are in good agreement with the indoor model test results.

Three Dimensional Finite Element Analysis of Subway Shield Tunnel under Exsisting Bridge

2013 ◽  
Vol 310 ◽  
pp. 206-209
Author(s):  
Yu Lin Zou ◽  
Chuan He ◽  
Zheng Zhang ◽  
Wei Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Shield Tunnel ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Left And Right ◽  
Three Dimensional Finite Element ◽  
Bridge Foundation ◽  
Shield Machine

One city subway shield tunnel under-passing an existing bridge is analyzed, using the method of the three dimensional finite element analysis to simulate the process of excavating the left and right tunnel to get the data of the subsidence, lateral, stress of the bridge, besides the reaction of the upper structure of the bridge when the shield machine thrusting ahead. The results of the study show that the overall settlement value of the pier is not big, but around piers on both sides, the maximum lateral come to 2.6 mm, and the maximum tension, compression stress of the bridge foundation increased by 1.07MPa and 0.4MPa, and arch structure in construction process stress adverse, it is suggested that we should reinforce the soil around the tunnel treatment to control the bridge foundation of uneven settlement, and at the same time, the process of closely monitor the situation of arch bridge.

3D Numerical Analysis of Metro Station by PBA Method to Enlarge Existing Large-Size Shield Tunnel

2012 ◽  
Vol 170-173 ◽  
pp. 1673-1678
Author(s):  
Mei Yan ◽  
De Yun Ding ◽  
Xiu Ren Yang ◽  
Xiu Ren Yang ◽  
Wei Dong Lu ◽  
...  
Keyword(s):  
Soil Structure ◽  
Three Dimensional ◽  
Element Model ◽  
Shield Tunnel ◽  
Interaction Theory ◽  
Metro Station ◽  
Large Size ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Station Structure

There is no engineering experience for metro station construction by the PBA (Pile-Beam-Arch) method to enlarge an existing large-size shield tunnel in China. During enlarging construction by the PBA method, the spatial mechanical and deformational characteristics of metro station structure are still not clear. In this paper, the Gaojiayuan station is taken as an engineering background to study the spatial mechanical and deformational characteristics during enlarging construction by the PBA method. Based on soil-structure interaction theory, a three-dimensional finite element model is built to simulate the enlarging construction by the PBA method. The three-dimensional numerical results can be regarded as a valuable reference for enlarging construction by the PBA method in Beijing metro line 14.

scholarly journals Stability Analysis of High-Pile and high-pier Considering Initial Pier Deviation

2021 ◽  
Vol 261 ◽  
pp. 02050
Author(s):  
Mei-Liang Zhu ◽  
Li-Qing Zhang ◽  
Ye Ma ◽  
Shun-Kun Jiang
Keyword(s):  
Three Dimensional ◽  
Horizontal Displacement ◽  
Nonlinear Buckling ◽  
Buckling Loads ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
High Pier ◽  
The Stability ◽  
Three Dimensional Finite Element ◽  
Better Than

Based on the high-pile and high-pier bridge of Qianhuang Expressway, eigenvalue buckling analysis is carried out by establishing three-dimensional finite element models of three different bridge types and high-pier types, and the corresponding structural nonlinear buckling loads under different initial pier deviations are calculated. The calculation results show that the nonlinear buckling loads of three high-pier types are less than elastic buckling loads. The stability of column high-pile and high-pier of continuous bridge is better than that of simple supported bridge, and the stability of plate high-pier is better than that of other two high-piers. In addition, the corresponding buckling load decreases with the increase of the initial horizontal displacement, indicating that the pier top offset of the high-pile and high-pier bridge is not conducive to the stability of the structure.

Three Dimensional Finite Element Modeling and Analysis of Different Subway Tunnels Stray Current Fields

2014 ◽  
Vol 8 (1) ◽  
pp. 124-132
Author(s):  
Guo Wang ◽  
Xiao-Xiang Pei
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Shield Tunnel ◽  
Geological Condition ◽  
Subway Tunnel ◽  
Stray Current ◽  
Modeling And Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In order to analyze the distribution rules and influence of stray current on subway rectangulartunneland subway Shield tunnel, threedimensional models were built separately. By changing the values of carry-current, ansys was used toanalyzeunder different geological conditions.Simulations show that the potential attenuation is nonlinear from the subway tunnel to the surrounding underground.The potential of the same location of surrounding media is different with different carry-current.The amount of leakage stray current of rectangular tunnel is less than Shield tunnel under same geological condition and same carry-current. Each points stray current in situation of surrounding soil media subway tunnel shield can be analyzed by the three-dimensional finite element model, and provide the basis for the protection range of stray current and the protection at a specific location.

Gear Contact Model and Loaded Tooth Contact Analysis of a Three-Dimensional, Thin-Rimmed Gear

2002 ◽  
Vol 124 (3) ◽  
pp. 511-517 ◽  
Author(s):  
Shuting LI
Keyword(s):  
Three Dimensional ◽  
Contact Analysis ◽  
Deformation Model ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Load Distributions ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Loaded Tooth Contact Analysis ◽  
Three Dimensional Finite Element

This paper performs loaded tooth contact analysis of a three-dimensional, thin-rimmed gear (3DTRG) by presenting a method that combines the mathematical programming method with the three-dimensional, finite element method (3DFEM). Also, a face-contact and whole gear deformation model is used for the 3DTRG. 3DFEM programs for the contact analysis and strength calculation of the 3DTRG are developed successfully in a personal computer. By using this program, 3D tooth load distributions, tooth root strains and the tooth contact pattern of the 3DTRG are obtained. Calculation results are proved to be correct by experiments.

Finite-Element Calculations on the Stress of an Aramid Cord in a Clamped and Elongated Goodrich Block Fatigue Specimen

1990 ◽  
Vol 63 (2) ◽  
pp. 223-233 ◽  
Author(s):  
E. M. Winkler ◽  
M. C. de Jong
Keyword(s):  
Finite Element ◽  
Fatigue Test ◽  
Three Dimensional ◽  
Element Model ◽  
Cord Clamping ◽  
Viscoelastic Effects ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Three Dimensional Finite Element ◽  
Compression Area

Abstract In the Goodrich Block Fatigue Test, a rubber block containing a tire cord is cyclically compressed and extended. The retained strength of the cord, obtained after a certain running time, is a measure of the fatigue resistance of the cord. In this test, the compression and extension is applied to the clamps of the block. This induces an indirect loading of the cord through shear forces in the rubber. This cord load varies along its length and depends on variables such as cord modulus and diameter and rubber modulus and cannot be obtained experimentally. A three-dimensional finite-element model together with a calculation procedure is presented. With these, not only the overall force-displacement behavior of the GBF specimen can be predicted, but also the detailed cord stress distribution, both for clamping and elongating the specimen. Only three different linear finite-element computations have to be performed. Results at any arbitrary elongation of the specimen are obtained by superposition of these calculation results. The accuracy can be enhanced by combining them with the measured value for the elongation at which the cord is just fully tensioned. Experimental verification was carried out for an aramid cord with a diameter of 0.6 mm. The presented model produces results that agree well with the measured values for the force on the specimen (both for clamping and elongating) and for the breaking force of the cord. Clamping of the specimen causes compression of the cord in the center area of the block. For the aramid cord used in this study, this compression area has a length of about 10 mm. At an elongation of approximately 0.4 mm (the corresponding extension setting of the machine is 3%), the cord is just fully tensioned. When elongating the block a certain amount above this setting, the stress in the center of the aramid cord is only 6.3% of the stress of a cord which would be strained the same amount as the block. In this study, no account has been taken of temperature and viscoelastic effects, which may play an important role in the actual fatigue test!

scholarly journals Study on Stability of Shield Tunnel Excavation Face in Soil-Rock Composite Stratum

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Hongtao Sui ◽  
Chao Ma ◽  
Chunquan Dai ◽  
Tingzhi Yang
Keyword(s):  
Limit Equilibrium ◽  
Three Dimensional ◽  
Earth Pressure ◽  
Calculation Model ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Practical Engineering ◽  
Three Dimensional Finite Element

In order to study the instability mode of shield excavation face in soil-rock composite stratum and determine the ultimate support pressure of excavation face, this paper selects two typical soil-rock composite strata and uses three-dimensional finite element software to study the failure development process of shield excavation face. Based on the principle of limit equilibrium, a calculation model of limit support pressure for soil-rock composite stratum is proposed and applied to practical engineering. It is found that the shape of “unloading loosening zone” is mainly determined by the properties of upper soil and the properties of lower rock mainly determine the scope and shape of “sliding instability zone.” With the increase of soil proportion coefficient, the ultimate bearing capacity increases nonlinearly and the growth rate decreases gradually. At the same time, the influence of overlying Earth pressure and soil cohesion cannot be ignored.

scholarly journals Comparative Study on Grouting Protection Schemes for Shield Tunneling to Adjacent Viaduct Piles

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Kan Huang ◽  
Yiwei Sun ◽  
Jun He ◽  
Xianqiang Huang ◽  
Meng Jiang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Shield Tunnel ◽  
Shield Tunneling ◽  
Protection Measures ◽  
Dimensional Finite Element ◽  
Different Depths ◽  
Pass Through ◽  
Under Construction ◽  
Three Dimensional Finite Element

Shield tunnels will inevitably pass through viaduct piles at a close distance due to the extensive construction of subways and viaducts in the city. In order to understand the influence of shield tunneling on the deformation of existing pile foundation and grouting protection measures, based on an engineering case, Changsha Metro Line 5 (from South Gaoqiao station to Guitang station), a three-dimensional finite element model was established to analyze the deformation of bridge pile using grouting protection wall with different depths and shapes when the shield tunnel is under construction. The analytical results indicate that the grouting protection wall can effectively reduce the pile displacement; especially the grouting depth is 3 m below the bottom of the tunnel. Moreover, the L-shaped grouting protection wall can effectively reduce the longitudinal displacement of the piles. The present findings may provide a reference for the design and construction of shield tunnels passing through viaduct piles.

scholarly journals Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

2018 ◽  
Vol 220 ◽  
pp. 04008 ◽  
Author(s):  
Mikhail V. Murashov ◽  
Andrey V. Vlasov
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Numerical Errors ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Friction has a substantial influence on the metal forming at upsetting of cylindrical aluminum specimens. The finite element method is often used to investigate this problem. This paper aims to reveal possible numerical errors and obstacles related to the 3D finite element solution of the problem. The calculation results for the proposed numerical 3D-model are compared with the experimental data. The influence of friction is demonstrated and a good agreement on the tool displacement is obtained. The features of the numerical solution of the problem in the ANSYS finite element software are shown.

Sign in / Sign up

Export Citation Format

Share Document