scholarly journals Numerical Study to Evaluate Soil Strength due to Seismic Loading

2016 ◽  
Vol V5 (08) ◽  
Author(s):  
V Yogeshwaran ◽  
Keyword(s):  
Numerical Study ◽  
Seismic Loading ◽  
Soil Strength

Experimental and numerical study on circular tunnels under seismic loading

2014 ◽  
Vol 19 (5) ◽  
pp. 539-563 ◽  
Author(s):  
Giovanni Lanzano ◽  
Emilio Bilotta ◽  
Gianpiero Russo ◽  
Francesco Silvestri
Keyword(s):  
Numerical Study ◽  
Seismic Loading

2D seismic numerical analysis of segmental tunnel lining behaviour

2014 ◽  
Vol 47 (3) ◽  
pp. 206-216 ◽  
Author(s):  
Ngoc Anh Do ◽  
Daniel Dias ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Study ◽  
Seismic Loading ◽  
Element Model ◽  
Seismic Signal ◽  
Tunnel Lining ◽  
Induced Response ◽  
Static Solutions ◽  
Comparative Results ◽  
Tunnel System ◽  
Better Than

Segmental tunnel linings are now often used for seismic areas in many countries. Some prescriptions and guidelines specifically address the issue of seismic design. Unfortunately, the behaviour of segmental tunnel lining under seismic loads is still somewhat unclear. The influence of segment joints on tunnel lining behaviour during seismic loading has in fact not been quantitatively estimated in the literature. This paper presents a numerical study in order to investigate the performance of segmental tunnel lining under seismic excitation. Analyses have been carried out using a two-dimensional finite difference element model. The seismic signal obtained from an earthquake in Nice has been adopted as input. The numerical results show that a segmental lining can perform better than a continuous lining during an earthquake. The effect of plasticity of the soil constitutive model on the tunnel lining has also been highlighted. The results have indicated that an elastic analysis is not sufficient to determine the seismic induced response of a soil-tunnel system. Moreover, comparative results have pointed out that equivalent static solutions could result in smaller structural lining forces than those of a true dynamic analysis.

scholarly journals Numerical study on bearing capacity of a pile group next to a slope in unsaturated soils

2020 ◽  
Vol 195 ◽  
pp. 01006
Author(s):  
Amirreza Pourfatollah ◽  
Ali Pirjalili ◽  
Aliakbar Golshani
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Numerical Study ◽  
Pile Group ◽  
Soil Strength ◽  
Strength Parameters ◽  
Water Characteristics ◽  
Soil Shear Strength

The bearing capacity of a pile group mostly depends on parameters of the soil shear strength affected by the soil-water characteristics, especially in unsaturated soils. The soil shear strength is entirely affected by hydraulic stresses in unsaturated soil, such as precipitation and evaporation. Further, the bearing capacity of the pile installed on unsaturated soil depends on hydraulic stresses applied to the soil. Furthermore, slope vicinity may cause a severe decline in the pile bearing capacity. The present study aimed to investigate a pile group in unsaturated soil adjacent to a slope and analyzed the effect of the rainfall on the soil strength parameters. Thus, a numerical study has been performed using a finite difference software,i.e., FLAC2D. Besides, to investigate the model in a real situation, the intensity and duration of rainfall are considered to evaluate changes in hydraulic stresses. Finally, the results show that the rainfall causes a considerable decrease in soil strength parameters in unsaturated soil, leading to the reduction of the pile group bearing capacity and slope stability.

Numerical Study of Spudcan Foundation Penetrating Into Layered Soils

2005 ◽  
Author(s):  
Zarnaz Mehryar ◽  
Yuxia Hu
Keyword(s):  
Numerical Study ◽  
Strain Analysis ◽  
Small Strain ◽  
Soil Strength ◽  
Critical Distance ◽  
Adaptive Finite Element Method ◽  
Potential Hazard ◽  
Strength Ratio ◽  
Clay Layer ◽  
Layer Boundary

Spudcan foundation, penetrating into stratified soils is studied using H-adaptive finite element method (FE) together with Remeshing and Interpolation Technique with Small Strain model (RITSS). This is to investigate the potential hazard of punch-through failure in layered soil profiles. There are two series of analysis conducted. Firstly, for a pre-embedded spudcan foundation, a series of parametric studies has been undertaken in order to find the critical distance between the spudcan and the layer boundary, within which a punch-through failure is likely to occur. Soil profile is a uniform stiff clay layer overlaying a uniform soft clay layer with soil strength ratio (upper layer soil strength to lower layer strength) varying from 1 to 10. Secondly, continuous analysis has been undertaken for 2 cases with shear strength ratio of 2 and 3 and thickness of the upper stiff layer of one spudcan diameter. It is found that, in small strain analysis, the critical distance to the layer boundary is increasing with increasing the strength ratio. It reaches at a limit of 1.0 ∼ 1.25 D (D is the spudcan diameter) when the strength ratio is 5 or larger. In large deformation analysis, the critical distance is much lower than the one from small strain analysis. This is due to the trapped top layer soil underneath the spudcan, which cannot be simulated in small strain analysis.

scholarly journals Influence of using Micropiles as Retrofitting Method for Bridge Shallow Footing: Numerical Study

2021 ◽  
Vol 10 (4) ◽  
pp. 186-190
Author(s):  
Hassan. A. Abas ◽  
M.A. Ismaeil
Keyword(s):  
Seismic Hazard ◽  
Significant Influence ◽  
Numerical Study ◽  
Deformation Characteristic ◽  
Seismic Loading ◽  
Seismic Retrofitting ◽  
Before And After ◽  
Existing Bridges ◽  
Plaxis 3D ◽  
Shallow Footing

Seismic retrofitting of the existing bridges, which was not properly constructed for seismic loading, is necessary. This paper examines and evaluates the effect of using micropiles as retrofitting method to improve seismic performance for bridge shallow footing. Numerical simulations using Plaxis-3D have been performed to study the effect of using micropiles to mitigate the seismic hazard and enhance the deformation characteristic of bridge shallow footing. Displacement and acceleration induced by seismic loading before and after retrofitting were assessed and compared. The results showed a significant influence of the micropiles on the control of the displacement and acceleration during the seismic period

scholarly journals Numerical Analysis of Slope Stability under Reservoir Water Level Fluctuations Using a FEM-LEM-Combined Method

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qingxiang Meng ◽  
Kun Qian ◽  
Lin Zhong ◽  
Jinjian Gu ◽  
Yue Li ◽  
...  
Keyword(s):  
Slope Stability ◽  
Water Level ◽  
Large Scale ◽  
Numerical Study ◽  
Soil Strength ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Impact

Large-scale slopes at the banks of reservoirs pose a serious threat to the safety of hydropower stations. The fluctuation of the reservoir water level is a key factor in the slope stability. However, the parameters to describe the relationship among water content, matric suction, and soil strength are difficult to measure using unsaturated soil strength theory. To solve this problem, a simple FEM-LEM-combined scheme considering pore pressure, seepage force, and strength weakening is presented to calculate the safety factor. A numerical study on the impact of reservoir water level fluctuations on stability of a glaciofluvial deposit slope is implemented. Two typical profiles are used to estimate the stability of the glaciofluvial deposit slope in response to rising and lowering water levels. The results indicate that this method proposed a simple and efficient tool for water level-induced slope stability analysis.

scholarly journals Numerical Study of Piles Group under Seismic Loading in Frictinal Soil—Inclination Effect

2014 ◽  
Vol 03 (01) ◽  
pp. 15-21 ◽  
Author(s):  
Fadi Hage Chehade ◽  
Marwan Sadek ◽  
Douaa Bachir
Keyword(s):  
Numerical Study ◽  
Seismic Loading

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
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