scholarly journals Analysis of Damage and Permeability Evolution for Mudstone Material under Coupled Stress-Seepage

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3755
Author(s):  
Bin Liu ◽  
Jinlan Li ◽  
Quansheng Liu ◽  
Xuewei Liu
Keyword(s):  
Finite Element ◽  
Pore Pressure ◽  
Permeability Coefficient ◽  
Minimum Energy ◽  
Coupling Model ◽  
Capacity Expansion ◽  
Permeability Change ◽  
Permeability Evolution ◽  
Finite Element Software ◽  
Coupled Stress

Mudstone material in a deep roadway is under the coupled stress-seepage condition. To investigate the permeability change and damage development during rock excavation in roadways, a stress-seepage damage coupling model has been proposed. In this model, damage capacity expansion of mudstone material is considered as the initiation and propagation of micro-cracks and the fracture penetration. A damage variable is introduced into the proposed model based on the principle of minimum energy consumption. As a result, an elastoplastic damage constitutive equation is established. Then, the permeability evolution equation describing the micro-macro hydraulic behavior of mudstone is deduced via percolation theory, which can describe the characteristics of sudden permeability change after rock capacity expansion. Furthermore, a finite element model is established based on commercial finite element software-ABAQUS. The numerical model was firstly verified by comparison between experimental and simulation results. On the basis of it, numerical investigation of the temporal and spatial evolution law of pore pressure, damage and permeability coefficient during roadway excavation is undertaken. The numerical results indicate that with increase of construction time, pore pressure first increases and then decreases, while the damage zone and permeability coefficient increase gradually and finally nearly keep constant. The proposed coupling model and finite element method can describe damage and permeability evolution for mudstone material under coupled stress-seepage well.

Numerical Analysis for Excess Pore Pressure Dissipation Process for Pressed Pile Installation

2013 ◽  
Vol 405-408 ◽  
pp. 133-137
Author(s):  
Tai Quan Zhou ◽  
Feng Tan ◽  
Cheng Li
Keyword(s):  
Finite Element ◽  
Pore Pressure ◽  
Excess Pore Pressure ◽  
Soil Behavior ◽  
Element Analysis ◽  
Dissipation Process ◽  
Pile Installation ◽  
Finite Element Software ◽  
Modified Cam Clay ◽  
Excess Pore

The finite element analysis is performed on the excess pore pressure dissipation for pressed pile installation using the ABAQUS finite element software. The modified Cam-Clay model is used to model the soil behavior. The finite slide contact model is used to model the pressed pile installation process. Based on the geology stratum of soils and drainage conditions, the excess pore pressure dissipation process is analyzed using the proposed method. The initial excess pore pressure distribution along the pile depth and the pile radius direction is obtained. The excess pore pressure dissipation after 98 days is analyzed.

scholarly journals Effects of Groundwater Exploitation on Embankment for High-speed Railway Lines

2015 ◽  
Vol 9 (1) ◽  
pp. 417-422
Author(s):  
Luwei Huang ◽  
Hong Xiao ◽  
Song Yang ◽  
Yugang Han
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Great Influence ◽  
Coupling Model ◽  
High Speed Railway ◽  
Pumping Rate ◽  
Groundwater Exploitation ◽  
Finite Element Software ◽  
Train Operation ◽  
Pumping Rates

Groundwater exploitation will cause significant subsidence to the ground, then influence the deformation of embankment for high-speed railway lines, which may threaten the safety of train operation. To study the law of embankment deformation aroused by groundwater exploitation near high-speed railway lines, a 3D fluid-solid coupling model is established based on infiltrating solidification theory and using finite element software ABAQUS, and embankment deformations caused by different pumping rates and pumping distance are analyzed. The results show that pumping rate and pumping distance are both of great influence on the deformations of embankment for high-speed railway lines. Therefore, in order to control the effects of groundwater exploitation on embankment, it should be forbidden to add new pumping well near the railway lines and groundwater exploitation should be strictly limited within the influence scope.

Dynamic Response Analysis of Composite Soil Nailed Wall under Earthquake

2014 ◽  
Vol 915-916 ◽  
pp. 114-121
Author(s):  
Xue Lang Wang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Analysis ◽  
Pore Pressure ◽  
Response Analysis ◽  
Dynamic Response Analysis ◽  
Finite Element Software ◽  
Design And Construction

In this paper, with the help of the finite element software ADINA, an actual composite soil nailed wall was solved. The dynamic response of the composite soil nailed wall is analyzed and discussed under the EL-Centro and man-made Lanzhou accelerogram. And the variation principles of the soil nailed wall which subjected to the earthquake, and the earthquake coupled with pore pressure, are demonstrated respectively. The results of the FEM dynamic analysis can be a useful reference for engineers of the design and construction of the composite soil nailed wall.

scholarly journals Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Interface Debonding ◽  
Damage Evolution Equation ◽  
Finite Element Software

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

Effect of crack on free vibration of a pre-stressed curved plate

2021 ◽  
pp. 095440622199486
Author(s):  
Can Gonenli ◽  
Hasan Ozturk ◽  
Oguzhan Das
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Natural Frequency ◽  
Present Model ◽  
Mode Shapes ◽  
Load Parameter ◽  
Flexible Plate ◽  
Cantilever Plate ◽  
Finite Element Software ◽  
Aspect Ratios

In this study, the effect of crack on free vibration of a large deflected cantilever plate, which forms the case of a pre-stressed curved plate, is investigated. A distributed load is applied at the free edge of a thin cantilever plate. Then, the loading edge of the deflected plate is fixed to obtain a pre-stressed curved plate. The large deflection equation provides the non - linear deflection curve of the large deflected flexible plate. The thin curved plate is modeled by using the finite element method with a four-node quadrilateral element. Three different aspect ratios are used to examine the effect of crack. The effect of crack and its location on the natural frequency parameter is given in tables and graphs. Also, the natural frequency parameters of the present model are compared with the finite element software results to verify the reliability and validity of the present model. This study shows that the different mode shapes are occurred due to the change of load parameter, and these different mode shapes cause a change in the effect of crack.

Numerical solutions for strain-softening surrounding rock under three-dimensional principal stress condition

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sheng Yu-ming ◽  
Li Chao ◽  
Xia Ming-yao ◽  
Zou Jin-feng
Keyword(s):  
Finite Element ◽  
Principal Stress ◽  
Stress Condition ◽  
Strain Softening ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Strength Criterion ◽  
Surrounding Rock ◽  
Flow Rule ◽  
Finite Element Software

Abstract In this study, elastoplastic model for the surrounding rock of axisymmetric circular tunnel is investigated under three-dimensional (3D) principal stress states. Novel numerical solutions for strain-softening surrounding rock were first proposed based on the modified 3D Hoek–Brown criterion and the associated flow rule. Under a 3D axisymmetric coordinate system, the distributions for stresses and displacement can be effectively determined on the basis of the redeveloped stress increment approach. The modified 3D Hoek–Brown strength criterion is also embedded into finite element software to characterize the yielding state of surrounding rock based on the modified yield surface and stress renewal algorithm. The Euler implicit constitutive integral algorithm and the consistent tangent stiffness matrix are reconstructed in terms of the 3D Hoek–Brown strength criterion. Therefore, the numerical solutions and finite element method (FEM) models for the deep buried tunnel under 3D principal stress condition are presented, so that the stability analysis of surrounding rock can be conducted in a direct and convenient way. The reliability of the proposed solutions was verified by comparison of the principal stresses obtained by the developed numerical approach and FEM model. From a practical point of view, the proposed approach can also be applied for the determination of ground response curve of the tunnel, which shows a satisfying accuracy compared with the measuring data.

Research on Mesh Optimization of the Finite Element Calculation about Three-Dimensional Foundation Pit

2012 ◽  
Vol 487 ◽  
pp. 855-859
Author(s):  
Shi Lun Feng ◽  
Yu Ming Zhou ◽  
Pu Lin Li ◽  
Jun Li ◽  
Zhi Yong Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Mesh Optimization ◽  
Design Calculation ◽  
Foundation Pit ◽  
3D Design ◽  
Finite Element Software ◽  
Core Language ◽  
Grid Division

Abaqus finite element software can implement three-dimensional excavation design calculation, so authors used Python of Abaqus core language made the 3D design of foundation pit supporting program come ture and also did intensive study of mesh optimization during the process. Authors also did intensive comparison and analysis about grid division of the complex geometry foundation pit, through a regularization partion about a variety of special-shaped pit, we made the automatic division about the structural grid of all kinds of shapes foundation pit successful. On this basis, we achieved better calculation effects of the model. The article will introduce problems about optimization of grid in procedure.

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.

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