scholarly journals Numerical Analysis of the Preloading Consolidation of the Soft Foundation with a Plastic Drainage Plate

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Linjie Li ◽  
Shuaidong Yang ◽  
Tong Su
Keyword(s):  
Permeability Coefficient ◽  
Void Ratio ◽  
Great Influence ◽  
Secondary Development ◽  
Consolidation Process ◽  
Development Platform ◽  
Finite Element Software ◽  
Surcharge Preloading ◽  
Soft Foundation ◽  
Stress Changes

The permeability coefficient and void ratio are related to the stress state of the soil, which manifests as the temporal and spatial variability of consolidation. Based on the modified Cambridge model, this paper quotes the functional relationship between the soil permeability coefficient and void ratio and soil stress obtained by Tylor’s research and then uses finite-element software ABAQUS and its secondary development platform to establish a plastic drainage plate surcharge preloading numerical model that considers the influence of the void ratio and permeability coefficient with stress changes. The results show that considering the variability of the permeability coefficient in the consolidation process of the soft foundation has a great influence on the change of the consolidation state but has a small effect on the final consolidation state. For soft foundation surcharge preloading reinforcement treatment, if the strength of the soft foundation is low but the surcharge is large, the geometric nonlinearity and material nonlinearity should be considered. Using the theory of large deformation consolidation to calculate the consolidation of soil is closer to the actual situation.

scholarly journals Sensitivity analysis of seepage field in groundwater reservoir based on orthogonal test method

2020 ◽  
Vol 194 ◽  
pp. 05019
Author(s):  
Jiahuan HE ◽  
Dong LEI ◽  
Yue ZHANG ◽  
Xin GAO ◽  
Xiaoyu WANG
Keyword(s):  
Sensitivity Analysis ◽  
Permeability Coefficient ◽  
Orthogonal Experiment ◽  
Great Influence ◽  
Maximum Flow ◽  
Seepage Flow ◽  
Test Method ◽  
Seepage Field ◽  
Finite Element Software ◽  
Underground Dam

Based on the ADINA-T finite element software, the effects of different underground dam depths, widths and permeability coefficients on the seepage field in the underground reservoir were studied. Based on the sensitivity analysis and calculation of the three parameters of the underground dam based on the orthogonal experiment method, the depth and permeability coefficient of the underground dam have a significant effect on the sensitivity of the groundwater level drop height in front of the dam, the width and the permeability coefficient have a significant effect on the maximum flow velocity, and depth has great influence on seepage flow.

scholarly journals Characterization of Mechanical Heterogeneity in Dissimilar Metal Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4145
Author(s):  
He Xue ◽  
Zheng Wang ◽  
Shuai Wang ◽  
Jinxuan He ◽  
Hongliang Yang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Welded Joints ◽  
Structural Integrity ◽  
Material Interfaces ◽  
Mechanical Heterogeneity ◽  
Finite Element Software ◽  
Dissimilar Metal ◽  
Stress Changes

Dissimilar metal welded joints (DMWJs) possess significant localized mechanical heterogeneity. Using finite element software ABAQUS with the User-defined Material (UMAT) subroutine, this study proposed a constitutive equation that may be used to express the heterogeneous mechanical properties of the heat-affected and fusion zones at the interfaces in DMWJs. By eliminating sudden stress changes at the material interfaces, the proposed approach provides a more realistic and accurate characterization of the mechanical heterogeneity in the local regions of DMWJs than existing methods. As such, the proposed approach enables the structural integrity of DMWJs to be analyzed in greater detail.

Numerical Simulation for Residual Stress and Deformation of Surface Welding on Membrane Water-Wall

2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu
Keyword(s):  
Residual Stress ◽  
Great Influence ◽  
Residual Deformation ◽  
Welding Residual Stress ◽  
Finite Element Software ◽  
Welding Sequence ◽  
Surface Welding ◽  
Stress And Deformation ◽  
Welding Sequences ◽  
Residual Stress And Deformation

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.

scholarly journals Analytical Solution of Seepage Field in Karst Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chong Jiang ◽  
Han-song Xie ◽  
Jia-li He ◽  
Wen-yan Wu ◽  
Zhi-chao Zhang
Keyword(s):  
Analytical Solution ◽  
Permeability Coefficient ◽  
Complex Function ◽  
Great Influence ◽  
Pressure Head ◽  
Seepage Flow ◽  
Seepage Field ◽  
Karst Tunnel ◽  
Lining Structure ◽  
Initial Support

An analytical solution for the seepage field in water-filled karst tunnel is derived based on the inversion of complex function and groundwater hydraulics theory. The solution considers the distance between the tunnel and the cavern, the size of the cavern, and the properties of the lining structure, such as the permeability coefficient as well as the radius of the grouting ring. This paper also performed numerical simulations for two cases: the application of gravity and the absence of gravity. The numerical solution was obtained to verify the analytical solution, and a good agreement was found. Then, the effect of parameters is discussed in detail, including the distance between the tunnel and the cavern, the radius of the cavern, the grouting ring, and the initial support. The results show that when the radius of the cavern is constant, the pressure head and seepage flow decrease as the distance between the tunnel and the cavern increases. When the distance is constant, the pressure head and seepage flow increase with the increase of the radius of the cavern. In addition, the pressure head and the seepage flow decrease with the increase of the thickness of the grouting ring and decrease with the decrease of the permeability coefficient. As the thickness of the initial support increases, the pressure head gradually increases and the percolation decreases. Furthermore, due to the great influence of the grouting ring and initial support on the pressure head and seepage flow, the thickness and permeability coefficient of the grouting ring and initial support should be taken into account carefully during construction.

Dynamic Response Analysis of Docking Chamber Structure Considering Viscoelastic Boundary Condition

2013 ◽  
Vol 405-408 ◽  
pp. 1939-1944
Author(s):  
Gui Lan Tao ◽  
Li Zhang
Keyword(s):  
Boundary Conditions ◽  
Secondary Development ◽  
Response Analysis ◽  
Elastic Model ◽  
Cross Point ◽  
Finite Element Software ◽  
Structure Response ◽  
Structure Dynamic ◽  
Fixed Boundaries ◽  
Incident Waves

Spring-damper units were set on the boundaries to absorb incident waves and reflected scattering waves to realize viscoelastic artificial boundary (VAB). The equivalent node load input method was used to simulate the VAB and viscoelastic boundary element wave input. Programming is based on APDL secondary development language with ANSYS finite element software. Considering the interaction between chamber structure and the surrounding soil, docking chamber structure dynamic model is established based on the VAB. The linear elastic model was used for concrete structure. The D-P nonlinear model was used for the back soil calculation. Docking chamber structure dynamic analysis under conditions of fixed boundaries and viscoelastic boundaries were conducted. The result indicated that under the viscoelastic boundary conditions, dynamic acceleration response is significant on the top of the lock wall, which is approximately 2.5 times of the value on the bottom of the lock wall. The maximum response stress appears near the cross point of the lock wall and the bottom floor with value of approximately 5620 kPa;.The chamber bottom floor is subjected to tension and maximum stress with the value of approximately 6180 kPa. Usually, the structure response under the fixed boundary conditions is higher than the structure response under the viscoelastic boundary conditions.

scholarly journals Deep permafrost evolution in unstable slopes during the Holocene

2018 ◽  
Author(s):  
Julien Seguinot
Keyword(s):  
Slope Failure ◽  
Time Lag ◽  
Great Influence ◽  
Ground Surface ◽  
Heat Diffusion ◽  
Failure Initiation ◽  
Finite Element Software ◽  
Hand Model ◽  
The One ◽  
Ice Pressure

Large alpine landslides dynamics are generally associated with Quaternary glacier retreat. Some recent datations demonstrate that several thousand years can separate the slope failure initiation from ice pressure unloading. The current study addresses the question whether the persistence of deep permafrost could produce this time lag. A model of deep permafrost evolution is developed, including heat diffusion, phase change and a ground surface transfer function. It is numerically implemented by a 1D finite difference code on the one hand and into a 2D finite element software on the other hand. Model results reveals the great influence of porosity and near-ground processes in permafrost evolution, and illustrates the possible persistence of a permafrost core into the slope.

Impact Dynamics Analysis of Shed Tunnel Structure Hit by Collapse Rock-Fall

2011 ◽  
Vol 99-100 ◽  
pp. 1023-1026 ◽  
Author(s):  
Lu Yang ◽  
Shi Min Li ◽  
Dai Heng Chen ◽  
Zhi Min Wu
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Incident Angle ◽  
Great Influence ◽  
Rock Fall ◽  
Tunnel Structure ◽  
Protective Structure ◽  
Additional Energy ◽  
Finite Element Software ◽  
The Impact

This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable: Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement; Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage; From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviate the impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.

scholarly journals Sub-impacts of simply supported beam struck by steel sphere—part II: Numerical simulations

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668335
Author(s):  
Xiaoli Qi ◽  
Xiaochun Yin
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Great Influence ◽  
Element Model ◽  
Theoretical Expression ◽  
Curvature Radius ◽  
Steel Sphere ◽  
Impact Time ◽  
Finite Element Software ◽  
Contact Impact

This part of the article describes numerical simulations of the problem investigated experimentally. A three-dimensional finite element model of elastic–plastic for sphere falling on beam has been implemented using the nonlinear dynamic finite element software LS-DYNA. From the numerical simulations, it was found that the LS-DYNA is suitable to study complex sub-impact phenomenon, and good agreement is in general obtained between the simulation and experimental results. The numerical simulations show that the initial impact velocity, equivalent elasticity modulus, contact curvature radius of the sphere, and equivalent mass have great influence on the contact–impact time of the sub-impact, and an applicable range of the theoretical expression of contact–impact time of the sub-impact was determined. In addition, the numerical simulations demonstrate the ratios of maximum amplitudes of the first-, second-, and third-order vibrations to the maximum amplitudes of the beam vibrations, and the phase angle of the first-order vibration will change suddenly when the sub-impacts occur. Furthermore, the occurrence conditions of the sub-impacts were clarified numerically. It was found that the occurrence conditions of the sub-impacts can be represented by a mass ratio threshold, and the thickness or length of the beam has also a great influence on the occurrence of the sub-impacts. Once the sub-impacts occur, which would result in an uncertain behavior of the apparent coefficient of restitution.

The Research and the Development of the 3D System Platform of Shafting Parts Based on CAA

2016 ◽  
Vol 693 ◽  
pp. 1886-1892 ◽  
Author(s):  
Hui Min Fang ◽  
Gang Zhao ◽  
Guo Zheng Zhang ◽  
Ping Xiao
Keyword(s):  
Secondary Development ◽  
Test Results ◽  
System Operation ◽  
Development Environment ◽  
Design Efficiency ◽  
Development Platform ◽  
Rapid Design ◽  
Component Development ◽  
Set Up

The enterprises when the designer worked with CATIA. In order to improve the efficiency, the research took the shaft parts as the research object to realize the secondary development of CATIA V5R18. The development platform of Shafting parts was set up through the embedded component development environment of CATIA CAA RADE and CAA API and was based on the development platform of VC++. At the end, this paper took the typical parts as examples to introduce the method of system operation. The test results show that this system could realize the rapid design and enhance the design efficiency, and it could provide the experience for the deeper development of CATIA.

Laboratory test investigations on soil water characteristic curve and air permeability of municipal solid waste

2018 ◽  
Vol 36 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Jianyong Shi ◽  
Xun Wu ◽  
Yingbo Ai ◽  
Zhen Zhang
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Water Content ◽  
Permeability Coefficient ◽  
Inflection Point ◽  
Void Ratio ◽  
Characteristic Curve ◽  
Air Permeability ◽  
Residual Water ◽  
Residual Water Content

The air permeability coefficient has a high correlation with the water content of municipal solid waste. In this study, continuous drying methodology using a tension meter was employed to construct the soil water characteristic curve of municipal solid waste (M-SWCC). The municipal solid waste air permeability test was conducted by a newly designed apparatus. The measured M-SWCC was well reproduced by the van Genuchten (V-G) model and was used to predict the parameters of typical points in M-SWCC, including saturated water content, field capacity, residual water content and water content at the inflection point. It was found that the M-SWCC was significantly influenced by void ratio. The final evaporation and test period of M-SWCC increase with the increase in void ratio of municipal solid waste. The evolution of air permeability coefficient with water content of municipal solid waste depicted three distinct characteristic stages. It was observed that the water contents that corresponded to the two cut-off points of the three stages were residual water content and water content at the inflection point, respectively. The air permeability coefficient of municipal solid waste decreased with the increase of the water content from zero to the residual water content. The air permeability coefficient was almost invariable when the water content increased from residual water content to the water content at the inflection point. When the water content of municipal solid waste exceeded the water content at the inflection point, the air permeability coefficient sharply decreased with the increase of water content.

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