scholarly journals A Comprehensive Numerical Study on Building-Excavation Interaction

2020 ◽  
Vol 6 (2) ◽  
pp. 326-343
Author(s):  
Arman Maddah ◽  
Abbas Soroush
Keyword(s):  
Numerical Study ◽  
Failure Surface ◽  
Embedment Depth ◽  
Deep Excavation ◽  
Building Foundation ◽  
Potential Failure ◽  
Building Characteristics ◽  
Parametric Analyses ◽  
3D Software ◽  
Story Building

This paper presents results of a plane strain comprehensive numerical study on the interaction between a 31-meter-deep excavation and an adjacent 12-story building; the study emphasizes on parametric analyses with respect to the building characteristics, such as the building width in plan (B), i.e., the side perpendicular to the excavation wall, the embedment depth of the building foundation (D), as well as the building distance to the excavation edge (e). Through the parametric analyses and assuming different values for B, D, and e, settlements and rotations of the building and horizontal displacements of the excavation edge were computed and evaluated using the finite element method adopted in PLAXIS 3D software. Prior to the parametric study, the numerical modeling was verified by modeling a recorded case study, which is an anchored deep excavation adjacent to a 12-story building. The results of the parametric analyses suggest that for the given soil and excavation, (1) the position of the developing potential failure surface, PFS, in the soil behind the excavation is almost independent from the building location and (2) the position of the building with respect to the outcrop of the PFS in the excavation crest, i.e., if the building locates fully on the potential failure wedge or PFS intersect the building base, is the main factor affecting the induced displacements and rotations of the building.

Numerical Study of Optimal Location of Non-Circular Segmented Failure Surface in Soil Slope With Weak Soil Layer

2021 ◽  
Vol 12 (1) ◽  
pp. 111-141
Author(s):  
Navneet Himanshu ◽  
Avijit Burman ◽  
Vinay Kumar
Keyword(s):  
Numerical Study ◽  
Soil Layer ◽  
Failure Surface ◽  
Detailed Comparison ◽  
Global Optimum ◽  
Weak Soil ◽  
Critical Failure Surface ◽  
Potential Failure ◽  
Swarm Size ◽  
Contemporary Standard

The article addresses stability analysis of complicated slopes having weak soil layer sandwiched between two strong layers. The search for critical failure surface and associated optimum/minimum factor of safety (FOS) among all potential failure surfaces can be posed as an optimization problem. Two different variants of particle swarm optimization (PSO) models, namely inertia weight-based PSO (IW-PSO) and contemporary standard PSO (CS-PSO), are used to obtain optimum global solution. Detailed comparison between the global optimum solutions obtained from two PSO variants and the effect of swarm size is studied. The performance of IW-PSO and CS-PSO are studied by observing the convergence behavior of the respective algorithms with respect to iteration count. The influence of velocity clamping on the optimized solution is investigated and its use is found beneficial as it prevents the solution from overflying the region with global best solution. The studies related to swarm diversity demonstrating the exploitation and exploration behaviors of the algorithms are also presented.

scholarly journals 3-D Numerical Study of Mechanical Behaviors of Pile-Anchor System

2014 ◽  
Vol 580-583 ◽  
pp. 238-242
Author(s):  
Ri Cheng Liu ◽  
Bang Shu Xu ◽  
Bo Li ◽  
Yu Jing Jiang
Keyword(s):  
Simulation Analysis ◽  
Numerical Study ◽  
Bending Moments ◽  
Mechanical Behaviors ◽  
Foundation Pit ◽  
Anchor System ◽  
Anchor Cable ◽  
Axial Forces ◽  
Toppling Failure ◽  
Potential Failure

Mechanical behaviors of pile-soil effect and anchor-soil effect are significantly important in supporting engineering activities of foundation pit. In this paper, finite difference method (FDM) was utilized to perform the numerical simulation of pile-anchor system, composed of supporting piles and pre-stressed anchor cables. Numerical simulations were on the basis of the foundation pit of Jinan’s West Railway Station, and 3D simulation analysis of foundation pit has been prepared during the whole processes of excavation, supporting and construction. The paper also analyzed the changes of bending moments of piles and axial forces of cables, and discussed mechanical behaviors of pile-anchor system, through comparisons with field monitoring. The results show that the parameters concluding vertical gridding’s number, cohesion of pile and soil, and pile stiffness have robust influences on supporting elements’ behaviors. Mechanical behaviors of supporting pile and axial forces of anchor cable changed dramatically, indicating that the potential failure form was converted from toppling failure to sliding failure.

scholarly journals A Theoretical Consideration of the Strength of Snow

1966 ◽  
Vol 6 (43) ◽  
pp. 159-170 ◽  
Author(s):  
G. E. H. Ballard ◽  
E. D. Feldt
Keyword(s):  
Theoretical Consideration ◽  
Failure Surface ◽  
Maximum Strength ◽  
Age Hardening ◽  
Temperature Dependent ◽  
Dependent Parameter ◽  
Potential Failure ◽  
Image Position

AbstractA consideration of possible expressions for the number and size of bonds intersected by a potential failure surface leads to the following expression for the strength of snow, σf, which is age-hardening at a constant porosity n: where σi is the strength of ice, tf is the time at failure, α is a parameter specifically related to the mechanism of bonding, and ω is a temperature-dependent parameter. Allowing tf to become infinite provides the envelope of maximum strength for fully age-hardened snow at any porosity n.

Test and Numerical Study on the Seismic Performance of A Cable Restrainer for Girder Bridges

2019 ◽  
Author(s):  
Yitong Gu ◽  
Wancheng Yuan ◽  
Xinzhi Dang
Keyword(s):  
Seismic Performance ◽  
Numerical Study ◽  
Design Method ◽  
Lateral Displacement ◽  
Static Test ◽  
Girder Bridges ◽  
Continuous Girder Bridge ◽  
Service Conditions ◽  
Girder Bridge ◽  
Parametric Analyses

<p>In China, most of the support systems applied by short/medium span bridges are elastomeric pad bearings (EPBs). This type of support system has no reliable connections between bearings and girders as well as bearings and piers, which will cause structural damages due to large lateral displacement of bearings under earthquakes. The restrainers used currently could restrict the deformation of bridges under normal service conditions and could only restrict unidirectional displacement. Considering the disadvantages of these restrainers, a new restrainer called Connected Cable Restrainer (CCR), which can be used in short/medium span bridges supported by EPBs, is developed in this paper. The design principle, basic configuration, isolation mechanism and the design method of CCR are introduced. A pseudo static test to study the seismic performance of CCR is conducted. Seismic responses of a 3-span continuous girder bridge with CCR are simulated using OpenSees platform and parametric analyses of the two main parameters, lateral restraining displacement and restraining stiffness, are also carried out. Results show that the deformation of bridges under normal service conditions would not be restrained using CCR and the displacement responses can be mitigated effectively by using CCR through parameter optimization.</p>

Numerical Analysis on the Bearing Capacity of Single Pile in Deep Excavation Area

2013 ◽  
Vol 671-674 ◽  
pp. 226-229
Author(s):  
Jun Jie Wu ◽  
Jin Jian Chen ◽  
Shuai Jun Liu ◽  
Jian Hua Wang
Keyword(s):  
Bearing Capacity ◽  
Large Scale ◽  
Numerical Study ◽  
Back Analysis ◽  
Load Test ◽  
Deep Excavation ◽  
Static Load Test ◽  
Fem Modeling ◽  
Vertical Bearing ◽  
Element Technique

Large-scale deep excavation may affect the bearing capacity of piles inside the excavation zone. It does not only cause the loss of friction, but also change the stress state of the subsoil. In this paper, nonlinear finite element technique is employed to investigate the bearing capacity of piles influenced by the deep excavation. Parameters of soil are obtained by back analysis on the pile static load test results. The bearing capacity of the piles during excavation is analyzed by performing FEM modeling under three conditions using the calibrated parameters. The numerical study shows that the loss ratio of vertical bearing capacity of pile foundation caused by excavation unloading is 34%.

A numerical study of the influence of Z-pin parameters on the elastic properties of laminates

2020 ◽  
pp. 096739112097008
Author(s):  
Mengjia Li ◽  
Puhui Chen
Keyword(s):  
Elastic Properties ◽  
Composite Laminates ◽  
Numerical Study ◽  
Element Model ◽  
Fe Model ◽  
Insertion Angle ◽  
Benchmark Tests ◽  
Parametric Analyses ◽  
Longitudinal Modulus ◽  
The Impact

A finite element model with periodic boundary conditions was developed to investigate the influence of different Z-pin parameters including diameter, spacing, and insertion angle of Z-pin on the elastic properties of composite laminates. Benchmark tests were carried out to verify the FE model and a series of parametric analyses were subsequently performed. In general, all the elastic moduli, excluding the through-thickness modulus ( Ez), decreased while Ez increased nonlinearly with increasing Z-pin diameter and decreasing spacing. The reduction of Ey (transverse modulus) was approximately 40% of that of Ex (longitudinal modulus), while the reduction of Gxy is similar to that of Ex. Besides, Gxz and Gyz were reduced by approximately half of the reduction of Gxy. Although the impact of insertion angle was obvious on Ez, it was negligible on the other five moduli.

A Numerical Study on the Pull-Out Strengths of Anchor Bolts Embedded in Concrete Using the Smoothed Particle Hydrodynamics Method

2016 ◽  
Vol 711 ◽  
pp. 1111-1117 ◽  
Author(s):  
Yoshimi Sonoda
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Failure Modes ◽  
Numerical Study ◽  
Failure Process ◽  
Embedment Depth ◽  
Anchor Bolt ◽  
Pull Out ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Anchor Bolts

The strength of an anchor bolt in concrete structure under pull-out load is usually designed by three possible failure modes such as fracture of anchor bolt, cone failure of concrete and bond failure between anchor bolt and concrete. In general, the design load is considered the smallest load corresponding to the aforementioned failure mechanisms. However, unexpected failure often occurs in the anchorage zone due to the complex failure or the change of failure condition. Therefore, it is important to develop the accurate analysis method of ultimate load bearing capacity of the anchor bolt. In this study, we conducted an analytical study using Adaptive Smoothed Particle Hydrodynamics (ASPH) in order to simulate the failure process of anchorage zone and discussed the effect of embedment depth of anchor bolts on their ultimate strength.

scholarly journals Pressure Settlement Behaviour and Bearing Capacity of Asymmetric Embedded Plus Shaped Footing on Layered Sand

2021 ◽  
Vol 31 (3) ◽  
pp. 152-176
Author(s):  
Priyanka Rawat ◽  
Rakesh Kumar Dutta
Keyword(s):  
Bearing Capacity ◽  
Numerical Study ◽  
Friction Angle ◽  
Thickness Ratio ◽  
Embedment Depth ◽  
Loose Sand ◽  
Dense Sand ◽  
Comparison Of The Results ◽  
Abaqus Software ◽  
Settlement Behaviour

Abstract The aim of the present numerical study was to analyse the pressure settlement behaviour and bearing capacity of asymmetric plus shaped footing resting on loose sand overlying dense sand at varying embedment depth. The numerical investigation was carried out using ABAQUS software. The effect of depth of embedment, friction angle of upper loose and lower dense sand layer and thickness of upper loose sand on the bearing capacity of the asymmetric plus shaped footing was studied in this investigation. Further, the comparison of the results of the bearing capacity was made between the asymmetric and symmetric plus shaped footing. The results reveal that with increase in depth of embedment, the dimensionless bearing capacity of the footings increased. The highest increase in the dimensionless bearing capacity was observed at embedment ratio of 1.5. The increase in the bearing capacity was 12.62 and 11.40 times with respect to the surface footings F1 and F2 corresponding to a thickness ratio of 1.5. The lowest increase in the dimensionless bearing capacity was observed at embedment ratio of 0.1 and the corresponding increase in the bearing capacity was 1.05 and 1.02 times with respect to the surface footing for footings F1 and F2 at a thickness ratio of 1.5.

scholarly journals Numerical Study of the Behaviour of a Circular Footing on a Layered Granular Soil Under Vertical and Inclined Loading

2021 ◽  
Vol 31 (1) ◽  
pp. 29-43
Author(s):  
Surya Pratap Singh ◽  
Amrit Kumar Roy
Keyword(s):  
Shear Failure ◽  
Numerical Study ◽  
Lower Layer ◽  
Failure Surface ◽  
Punching Shear ◽  
Dense Layer ◽  
Sand Layer ◽  
Dense Sand ◽  
Inclined Loading ◽  
Circular Footing

Abstract This paper aims to study the behaviour of a circular footing resting on two granular layers, i.e., a dense sand layer resting on loose sand strata, subjected to a vertical and an inclined loading (α=0°, 10°, 20°, 30°) using the finite element (FE) software PLAXIS-3D. The Mohr-Coulomb criterion is employed for the analysis of the model, in which two parameters are considered to vary significantly; (1) thickness of the top layer (dense layer) and (2) friction angle (ф) of both the layers. In the circular footing, the bearing capacity on the layered soil profile is assessed using the mechanism of punching shear failure following the desired area approach. The punching shear failure mechanism formed in dense sand has a parabolic shape at the ultimate load when the maximum mobilization of shear force through the failure surface is taken into account, otherwise, the punching failure is the actual failure while punching in the lower layer continues to a greater extent, depending on the interface load. Bearing pressure decreases as the inclination increases with respect to the vertical, along with bearing pressure increasing as the thickness of the dense sand layer increases. The software results compare well with data available from the literature.

scholarly journals Transmission Coefficient Analysis of Notched Shape Floating Breakwater Using Volume of Fluid Method: A Numerical Study

Kapal ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 41-50
Author(s):  
Asfarur Ridlwan ◽  
Haryo Dwito Armono ◽  
Shade Rahmawati ◽  
Tuswan Tuswan
Keyword(s):  
Numerical Simulations ◽  
Transmission Coefficient ◽  
Numerical Study ◽  
Soil Conditions ◽  
Current Application ◽  
Floating Breakwater ◽  
Computational Fluid Dynamics Cfd ◽  
Comparative Results ◽  
3D Software ◽  
Tidal Variations

As one of the coastal structures, breakwaters are built to protect the coastal area against waves. The current application of breakwaters is usually conventional breakwaters, such as the rubble mound type. Climate change, which causes tidal variations, sea level height, and unsuitable soil conditions that cause large structural loads, can be solved more economically by employing floating breakwater. In this study, numerical simulations will be conducted by exploring the optimum floating breakwater notched shapes from the Christensen experiment. The comparison of three proposed floating breakwater models, such as square notch (SQ), circular notch (CN), and triangular notch (VN), is compared with standard pontoon (RG) to optimize the transmission coefficient value is analyzed. Numerical simulations are conducted using Computational Fluid Dynamics (CFD) based on the VOF method with Flow 3D Software. Compared to the experimental study, the RG model's validation shows a good result with an error rate of 8.5%. The comparative results of the floating breakwater models are found that the smaller the transmission coefficient value, the more optimal the model. The SQ structure has the smallest transmission coefficient of 0.6248. It can be summarized that the SQ model is the most optimal floating breakwater structure.

Sign in / Sign up

Export Citation Format

Share Document