Numerical Analysis on Vibration Mitigation Effect of EPS Geofoam on Retaining Wall

2010 ◽  
Vol 168-170 ◽  
pp. 1038-1041
Author(s):  
De Ling Wang
Keyword(s):  
Retaining Wall ◽  
Expanded Polystyrene ◽  
Shaking Table ◽  
Finite Element Program ◽  
Physical Test ◽  
Eps Geofoam ◽  
Backfill Soil ◽  
Scale Models ◽  
Element Program ◽  
Rigid Walls

The mitigation of earth force by placing expanded polystyrene (EPS) geofoam buffer between retaining wall and backfill soil under dynamic loading is a topic worth consideration. In this paper, the effects of EPS geofoam buffer on the reduction of thrust wall force are numerically studied to simulate three reduced-scale models of rigid walls using a large shaking table. Numerical simulation technique using the finite element program Abaqus is described. The paper shows that the numerical Abaqus models are able to capture the trend in earth forces with increasing base acceleration for all three models. The use of the EPS geofoam as a compressible buffer yields obviously reduction of the lateral seismic thrust against retaining wall. The quantitative dynamic load–time response of the numerical simulations was in good agreement with measured physical test values.

scholarly journals Numerical Analysis of Earthquake Load Mitigation on Rigid Retaining Walls Using EPS Geofoam

2012 ◽  
Vol 6 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Deling Wang ◽  
Richard J. Bathurst
Keyword(s):  
Numerical Simulations ◽  
Retaining Wall ◽  
Expanded Polystyrene ◽  
Numerical Results ◽  
Shaking Table ◽  
Great Promise ◽  
Finite Element Program ◽  
Physical Test ◽  
Eps Geofoam ◽  
Element Program

The mitigation of seismic-induced dynamic earth forces by placing a vertical layer of expanded polystyrene (EPS) geofoam buffer between a rigid retaining wall and the backfill soil is a recent geotechnical innovation. In this paper, the influence of an EPS geofoam buffer on the reduction of dynamic wall forces is numerically studied by simulating the results of three reduced-scale models of rigid walls mounted on a large shaking table. Numerical simulations were carried out using the finite element program ABAQUS. The paper shows that the numerical results capture the trend in earth forces with increasing base acceleration for all three models. The quantitative dynamic load-time response from the numerical simulations was also judged to be in good agreement with measured physical test values. The numerical trend of EPS geofoam also is the same as that of measured test data. With the increasing time, the compression of EPS geofoam increases. And softer EPS geofoam produces more compression which takes more vibration energy by its deformation. The numerical results confirm the results of physical tests that demonstrate that EPS geofoam seismic buffers hold great promise to reduce earthquake-induced dynamic loads against rigid retaining wall structures.

Force and Compression Analysis for Rigid Retaining Walls with EPS Buffer

2011 ◽  
Vol 243-249 ◽  
pp. 959-962
Author(s):  
De Ling Wang ◽  
Li Guo
Keyword(s):  
Elastic Modulus ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Great Promise ◽  
Static Loads ◽  
Physical Test ◽  
Eps Geofoam ◽  
Backfill Soil ◽  
Vibration Loads ◽  
Simulation Results

In this paper, the force against rigid retaining walls from backfill soil under static loads and vibration loads is analyzed within three cases. The first case is an ordinary retaining wall without expanded polystyrene (EPS) geofoam buffer. In the second and the third case, a layer of vertical EPS buffer with different density and elastic modulus is placed between a rigid retaining wall and backfill soil. Numerical simulation results show that the force against the same retaining wall in the treated cases is less than that in the untreated case, under both static loads and vibration loads. Moreover, the compression of different EPS buffer is studied. Under vibration excitation, when the density and elastic modulus of EPS buffer decreases, its compression increases and more wall force is mitigated. Simulation results accord with the physical shaking table test data. Numerical results and physical test demonstrate that EPS geofoam seismic buffers hold great promise to reduce loads against rigid retaining wall structures, especially earthquake-induced dynamic loads.

scholarly journals Evaluating the Role of Geofoam Properties in Reducing Lateral Loads on Retaining Walls: A Numerical Study

2021 ◽  
Vol 13 (9) ◽  
pp. 4754
Author(s):  
Muhammad Imran Khan ◽  
Mohamed A. Meguid
Keyword(s):  
Numerical Study ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Expanded Polystyrene ◽  
Wall Structure ◽  
Eps Geofoam ◽  
Lateral Earth Pressure ◽  
Backfill Soil

Expanded polystyrene (EPS) geofoam is a lightweight compressible material that has been widely used in various civil engineering projects. One interesting application of EPS in geotechnical engineering is to reduce the lateral earth pressure on rigid non-yielding retaining walls. The compressible nature of the EPS geofoam allows for the shear strength of the backfill soil to be mobilized, which leads to a reduction in lateral earth pressure acting on the wall. In this study, a finite element model is developed and used to investigate the role of geofoam inclusion between a rigid retaining wall and the backfill material on the earth pressure transferred to the wall structure. The developed model was first calibrated using experimental data. Then, a parametric study was conducted to investigate the effect of EPS geofoam density, relative thickness with respect to the wall height, and the frictional angle of backfill soil on the effectiveness of this technique in reducing lateral earth pressure. Results showed that low-density EPS geofoam inclusion provides the best performance, particularly when coupled with backfill of low friction angle. The proposed modeling approach has shown to be efficient in solving this class of problems and can be used to model similar soil-geofoam-structure interaction problems.

Analysis of Raft Foundation with EPS Geofoam for Earthquake Resistant

2014 ◽  
Vol 695 ◽  
pp. 613-616
Author(s):  
Mohd Faiz Mohammad Zaki ◽  
Mohammad Fadzli Ramli ◽  
Afizah Ayob ◽  
Mohd Taftazani Ahmad
Keyword(s):  
Structural Engineering ◽  
Soft Soil ◽  
Simulation Models ◽  
Soil Mass ◽  
Dynamic Force ◽  
Finite Element Program ◽  
Eps Geofoam ◽  
Raft Foundation ◽  
Element Program ◽  
Innovative Material

It is becoming a great challenge for civil engineers to design a foundation which able to minimize the effect of an earthquake. A major earthquake produces a strong ground motion in the subsoil and surface structures supported on the soil mass will be induced to move and absorb the dynamic forces. Seismic retrofit of existing foundations is an alternative. However, the modification of this existing foundation toward earthquake resistances raises issues which are far from being totally resolved. Innovative material such as EPS is widely accepted in structural engineering due to its characteristic to absorb the dynamic force effectively. This EPS material demonstrated the practicality and has been applied for geotechnical engineering for various reasons. Based on this, a research which is related to the application of EPS in mitigating the earthquake forces, particularly for raft foundations was conducted properly in this research. The various types and thickness of EPS located beneath the raft foundation and over the soft soil are studied. A finite element program is utilized to develop the computer simulation models. Based on the results, Expended Polystyrene (EPS) Geofoam, placed beneath the raft foundation is able to produces the minimum settlements when subjected to earthquake loading rather than raft foundation modeled without EPS and increasing the density of EPS will simultaneously decrease the settlement of a foundation.

Numerical parametric study of expanded polystyrene (EPS) geofoam seismic buffers

2009 ◽  
Vol 46 (3) ◽  
pp. 318-338 ◽  
Author(s):  
Saman Zarnani ◽  
Richard J. Bathurst
Keyword(s):  
Numerical Study ◽  
Retaining Wall ◽  
Expanded Polystyrene ◽  
Buffer System ◽  
Predominant Frequency ◽  
Eps Geofoam ◽  
Wall Structures ◽  
Earthquake Record ◽  
Numerical Parametric Study ◽  
Parameter Values

Expanded polystyrene (EPS) geofoam seismic buffers can be used to reduce earthquake-induced loads acting on rigid retaining wall structures. A numerical study was carried out to investigate the influence of wall height; EPS geofoam type, thickness, and stiffness; and excitation record on seismic buffer performance. The numerical simulations were carried out using a verified FLAC code. The influence of parameter values was examined by computing the maximum forces on the walls, the buffer compressive strains, and the relative efficiency of the buffer system. In general, the closer the predominant frequency of excitation to the fundamental frequency of the wall model, the greater the seismic loads and buffer compression. The choice of earthquake record is shown to affect the magnitude of maximum earth force and isolation efficiency. However, when the wall response for walls 3 to 9 m in height are presented in this study in terms of isolation efficiency, the data from scaled accelerograms and matching harmonic records with the same predominant frequency fall within a relatively narrow band when plotted against relative buffer thickness. For the range of parameters investigated, a buffer stiffness value less than 50 MN/m3 was judged to be the practical range for the design of these systems.

Analysis of Soil Nailing under Earthquake Loading in Malaysia Using Finite Element Method

2014 ◽  
Vol 695 ◽  
pp. 526-529 ◽  
Author(s):  
Mohd Faiz Mohammad Zaki ◽  
Wan Amiza Amneera Wan Ahmad ◽  
Afizah Ayob ◽  
Teoh Khai Ying
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Slope Failure ◽  
Retaining Wall ◽  
Seismic Loading ◽  
Soil Nailing ◽  
Deep Excavation ◽  
Finite Element Program ◽  
Total Displacement ◽  
Element Program

Soil nailing has become a widely accepted method and offers a practical solution towards construction of permanent retaining wall, slope stabilization and protection of existing cuts from failure. In Malaysia, soil nailing is typically performed on cut slope and installed with grouting as preventatives method due to erosion problem. However, although the effectiveness of soil nailing system may be well understood by practitioners, the slope failure and collapses of deep excavation are continuously occurs, especially for the construction in the earthquake zone. Malaysia has numerous experiences of earthquake even this country has been categorized as low seismicity group. Hence, it is become important in the scope of geotechnical engineering to analyze and study the effect of earthquake to soil nailing systems in Malaysia. Aims of this paper are to focus and study this technical issue using the application of finite element program. This research study selects PGA of 0.08g based on the location of major population in Malaysia. Safety factor was calculated in this finite element program using phi-c reduction. Soil nailing relatively give satisfactory response under seismic, so pseudo-static method is applied for seismic loading study. Based on the static analysis results, the FOS for the deep excavation stabilized with soil nailing is 1.54. However, by considering the earthquake or seismic loading, the FOS reduces to 1.16 and the percentage of reduction is about 25%. Total displacement was observed slightly difference in soil nailing analysis during an earthquake and static analysis

scholarly journals Behavior of Reinforced Retaining Walls with Different Reinforcement Spacing during Vehicle Collisions

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Kwangkuk Ahn ◽  
Hongsig Kang
Keyword(s):  
Retaining Wall ◽  
Retaining Walls ◽  
Analysis Model ◽  
Finite Element Program ◽  
Vehicle Collision ◽  
Reinforcement Material ◽  
Element Program ◽  
Reinforced Retaining Wall ◽  
Truck Weight ◽  
Variable Reinforcement

Accidents involving vehicles crashing into reinforced retaining walls are increasing because of the increased construction of reinforced retaining walls on roads. Unlike a normal retaining wall, a reinforced retaining wall is not one united body but is made up of blocks. Hence, a reinforced wall can break down when a vehicle crashes into it. The behavior of such a wall during vehicle collision depends upon the reinforcement material used for its construction, its design, and the method of the construction. In this study, the behavior of a reinforced retaining wall was analyzed while changing the reinforcement spacing using LS-DYNA, a general finite-element program. Eight tons of truck weight was used for the numerical analysis model. The behavior of a reinforced retaining wall under variable reinforcement spacing and positioning was analyzed. The results indicated that the reinforcement material was an important resistance factor against external collision load.

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