scholarly journals Flexible Temporary Shield in Soft and Sensitive Clay: 3D FE Modelling of Experimental Field Test

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Miah Alam ◽  
Omar Chaallal ◽  
Bertrand Galy
Keyword(s):  
Field Test ◽  
Numerical Study ◽  
Earth Pressure ◽  
Maximum Load ◽  
Reduction Factor ◽  
Fe Analysis ◽  
Soil Pressure ◽  
Fe Modelling ◽  
Flexible Wall ◽  
Sensitive Clay

A finite-element (FE) numerical study using PLAXIS-3D software was carried out to reproduce and validate a full-scale experimental in situ test and to investigate the earth pressure on a flexible temporary trench box shield in soft and sensitive clay soil. The excavation trench model was 6 m (20 ft) deep and was considered as nonlinear and anisotropic clay. A 45 kPa (0.94 ksf) surface overload on top of the soil near the trench box was also simulated to produce a maximum load case on the flexible wall of the shield. Both Mohr-Coulomb (MC) and hardening soil (HS) constitutive soil models were considered for FE analysis. Different values of the modulus reduction factor (MRF) and the coefficient of earth pressure at rest ( K 0 ) were considered to validate the model. For a specific shear strength profile, FE analysis with a linear elastoplastic soil model showed relatively small differences in soil pressure with the field test results along the depth of the trench. Results were also compared with the predictions of well-established analytical formulae.

scholarly journals Soil-Structure Interaction of Flexible Temporary Trench Box: Parametric Studies Using 3D FE Modelling

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Miah Alam ◽  
Omar Chaallal ◽  
Bertrand Galy
Keyword(s):  
Finite Element ◽  
Plate Thickness ◽  
Earth Pressure ◽  
Material Model ◽  
Computer Code ◽  
Soil Pressure ◽  
Fe Modelling ◽  
Deep Trench ◽  
Constitutive Material Model ◽  
Sensitive Clay

This paper presents the results of two parametric finite-element studies that were carried out using the PLAXIS-3D finite element (FE) computer code. The following objectives and corresponding parameters were considered: (i) to evaluate the soil pressure on the steel trench box shield; the parameters studied were related to soil type and material, and the study considered till, dry sand, wet sand, and sensitive clay soil; (ii) to assess the effect of trench box material and geometry on earth pressure; the parameters studied were related to trench box material (steel versus aluminum) as well as geometry (plate thickness and strut diameter). These studies included simulation of two steel (or aluminum) trench box shields stacked upon each other to cover the total 6 m (20 ft) deep trench. A Mohr-Coulomb (MC) constitutive material model was chosen for FE analysis (FEA). The FEA results were compared to empirical apparent earth pressure diagrams for a sensitive clay. Comparisons showed that the parameters related to the soil and the trench box have a significant influence on earth pressures.

Soil Pressure Test and Numerical Analysis on Reinforced Earth Retaining Wall of Green Gabion

2014 ◽  
Vol 644-650 ◽  
pp. 5039-5045
Author(s):  
Xiao Yang ◽  
Guo Lin Yang
Keyword(s):  
Numerical Analysis ◽  
Field Test ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Wall Surface ◽  
Soil Pressure ◽  
Reinforced Earth ◽  
Earth Pressures ◽  
Flexible Wall ◽  
Vertical Earth Pressure

Based on reinforced earth retaining wall of green gabion which is built at the site of seventh project Shaoxing-Zhuji Expressway, the research for soil pressure in a cross section which locate at the site of K38+398kmare made by field test and numerical analysis. The horizontal and vertical earth pressure are studied in the construction, The pressures between field test and numerical analysis which depend on FLAC3D are rough similar. With increased of height in filling soil, the earth pressures on the wall toe in 3 direction such as horizon , vertical, 45°are increased ,and then gradually come to stability after construction. With increased of height in filling soil, the vertical earth pressures is increased, but the distribution for earth pressure at the same height is non-uniform. The horizontal earth pressure on the back of wall surface increases fast at first then decreases a little, which is a single peak-shaped, it distributes along the wall height in non-linear form, the maximum occurs at 1/3H. The result between field test and numerical model are different, because the flexible wall surface has a great affection on unload.

Study on Vertical Earth Pressure of Slab Culvert under High Embankment

2012 ◽  
Vol 256-259 ◽  
pp. 1898-1902 ◽  
Author(s):  
Bao Kuan Ning ◽  
He Fan ◽  
Lei Gong ◽  
Guo Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Field Test ◽  
Structural Design ◽  
Earth Pressure ◽  
Test Results ◽  
Soil Pressure ◽  
Vertical Earth Pressure ◽  
The Impact ◽  
Good Agreement

With the increasing of embankment culvert engineering applications, there has been due in part to the structural design is too conservative and not economic or select unreasonable structural form, leading to the phenomenon of cracking or even collapse of the culvert structure, and the phenomenon has seriously affected the normal use of the highway. In this paper, the numerical simulation of vertical earth pressure distribution on different structural forms of embankment on culverts, to discuss the impact of boundary conditions, fill height, the thickness of the culvert culverts vertical earth pressure. Combined with Heda highway a culvert covert field test results and numerical simulation results were compared and analyzed. The results show that the numerical simulation and field test results in good agreement with the culvert structure in the form of vertical earth pressure of the embankment culverts have a greater impact; the structure of different forms of the culvert in the upper soil pressure is significantly different. In addition, analysis of the impact of boundary conditions, filling height of culvert vertical earth pressure values. The results can reference for the study of the structural design of the embankment culverts security.

scholarly journals Large-deformation finite-element modelling of earthquake-induced landslides considering strain-softening behaviour of sensitive clay

2019 ◽  
Vol 56 (7) ◽  
pp. 1003-1018 ◽  
Author(s):  
Naveel Islam ◽  
Bipul Hawlader ◽  
Chen Wang ◽  
Kenichi Soga
Keyword(s):  
Finite Element ◽  
Large Deformation ◽  
Large Scale ◽  
Slope Failure ◽  
Strain Softening ◽  
Limit Equilibrium ◽  
Fe Analysis ◽  
Plastic Shear ◽  
Fe Modelling ◽  
Sensitive Clay

Large-scale landslides in sensitive clays cannot be explained properly using the traditional limit equilibrium or Lagrangian-based finite-element (FE) methods. In the present study, dynamic FE analysis of sensitive clay slope failures triggered by an earthquake is performed using a large-deformation FE modelling technique. A model for post-peak degradation of undrained shear strength as a function of accumulated plastic shear strain (strain-softening) is implemented in FE analysis. The progressive development of “shear bands” (the zone of high plastic shear strains) that causes the failure of a number of soil blocks is simulated successfully. Failure of a slope could occur during an earthquake and also at the post-quake stage until the failed soil masses come to a new static equilibrium. Upslope retrogression and downslope runout of the failed soil blocks are examined for varying geometries and soil properties. The present FE simulations can explain some of the conditions required for different types of seismic slope failure (e.g., spread, flowslide or monolithic slides) to be triggered, as observed in the field.

scholarly journals CFRP Origami Metamaterial with Tunable Buckling Loads: A Numerical Study

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 917
Author(s):  
Houyao Zhu ◽  
Shouyan Chen ◽  
Teng Shen ◽  
Ruikun Wang ◽  
Jie Liu
Keyword(s):  
Numerical Study ◽  
Buckling Load ◽  
Fe Modelling ◽  
Buckling Loads ◽  
Folding Angle ◽  
Mechanical Responses ◽  
Reinforced Plastic ◽  
Rate Of Increase ◽  
Practical Engineering ◽  
Identical Rate

Origami has played an increasingly central role in designing a broad range of novel structures due to its simple concept and its lightweight and extraordinary mechanical properties. Nonetheless, most of the research focuses on mechanical responses by using homogeneous materials and limited studies involving buckling loads. In this study, we have designed a carbon fiber reinforced plastic (CFRP) origami metamaterial based on the classical Miura sheet and composite material. The finite element (FE) modelling process’s accuracy is first proved by utilizing a CFRP plate that has an analytical solution of the buckling load. Based on the validated FE modelling process, we then thoroughly study the buckling resistance ability of the proposed CFRP origami metamaterial numerically by varying the folding angle, layer order, and material properties, finding that the buckling loads can be tuned to as large as approximately 2.5 times for mode 5 by altering the folding angle from 10° to 130°. With the identical rate of increase, the shear modulus has a more significant influence on the buckling load than Young’s modulus. Outcomes reported reveal that tunable buckling loads can be achieved in two ways, i.e., origami technique and the CFRP material with fruitful design freedoms. This study provides an easy way of merely adjusting and controlling the buckling load of lightweight structures for practical engineering.

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

scholarly journals Monitoring a 28.5 m High Anchored Pile Wall in Gravel Using Various Methods

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 80 ◽  
Author(s):  
Ricardo Moffat ◽  
Pablo Parra ◽  
Miguel Carrasco
Keyword(s):  
Optical Fiber ◽  
Earth Pressure ◽  
Time Domain Reflectometry ◽  
Body Motion ◽  
Soil Pressure ◽  
Optical Time Domain Reflectometry ◽  
Excavation Process ◽  
Topographic Survey ◽  
Optical Time ◽  
Horizontal Displacements

Horizontal displacements of a multiple-anchor pile wall in a 28.5 m deep excavation using the top–down construction method have been monitored using optical fiber (Brillouin optical time-domain reflectometry (BOTDR)), strain gauges, inclinometers, and a topographic survey. This work presents a comparison between these different techniques to measure horizontal displacements in the pile at several stages of the soil excavation process. It was observed that displacements can be separated into two components: Rigid body motion and pile flexural deformation. Measurements using optical fiber and inclinometers are considered the most adequate and easy to install. A numerical model allows us to evaluate the influence of earth pressure on the estimated horizontal displacements. It is shown that using soil pressure on the wall given by p = 0.65Kaγh, on a simplified modeled wall, provides a close deduction of horizontal displacements compared to observed values on the field.

Structural Analysis of Riveted Structures Using a New FE Modelling Technique

2010 ◽  
Author(s):  
Michele Ferracci ◽  
Francesco Vivio ◽  
Vincenzo Vullo
Keyword(s):  
Degrees Of Freedom ◽  
Complex Structure ◽  
Element Model ◽  
3D Models ◽  
Fatigue Behaviour ◽  
Fe Analysis ◽  
Structural Behaviour ◽  
Fe Modelling ◽  
Closed Form Solutions ◽  
Riveted Joints

A theoretical approach, in order to define the structural behaviour of riveted joints, is presented. The closed form solutions lead to the definition of a Rivet Element useful to FE models of multi-riveted structures. The objective is an accurate evaluation of the local stiffness of riveted joints in FE analysis, which is fundamental to perform a reliable simulation of multi-joint structures and, consequently, a good estimate of loads acting on connections; this makes it possible to introduce new general criteria allowing, for example, to predict fatigue behaviour. On the other hand, a low number of degrees of freedom is needed when several connections are present in a complex structure. The goal is to reach a reliable model of the rivet region which can be used as the basis to develop a Rivet Element in FE analysis. The proposed Rivet Element combines the precision in the simulation with a very limited number degrees of freedom in the finite element model of a complex structure having several rivets. In the present paper the structural behavior of two simple riveted specimens is investigated experimentally and numerically using a new Rivet Element. A comparison with a joint model performed with very refined non-linear 3D models of rivet and with experimental data is performed and a good agreement is shown.

Numerical Study of Liquid Core Solidification in Influence of Soft Reduction Deformation on Steel Slab Continuous Casting Process

2008 ◽  
Vol 575-578 ◽  
pp. 80-86 ◽  
Author(s):  
J. Luo ◽  
Xin Lin ◽  
Yan Hong Ye ◽  
K.W. Liu
Keyword(s):  
Continuous Casting ◽  
Numerical Study ◽  
Liquid Core ◽  
Solidification Process ◽  
Casting Process ◽  
Reduction Factor ◽  
Two Dimensions ◽  
Temperature Function ◽  
Soft Reduction ◽  
Steel Slab

A two dimensions (2D) multiphase solidification model is used to study the liquid core solidification in the influence of deformation during soft reduction of continuous casting (CC). The transient transport equations (mass, momentum and enthalpy) for each phase of a thin steel slab CC are solved. Four different cases including of density-temperature function and deformation reduction factor on this CC are simulated. The solidification ending point position of liquid core, temperature, velocity and fracture of liquid and solid phases are compared. Understandings to the deformation and liquid core formation mechanism on soft reduction solidification process of CC are improved.

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