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.

scholarly journals Experimental and Numerical Study of At-Rest Lateral Earth Pressure of Overconsolidated Sand

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Magdi El-Emam
Keyword(s):  
Numerical Model ◽  
Numerical Study ◽  
Retaining Wall ◽  
Earth Pressure ◽  
System A ◽  
Lateral Earth Pressure ◽  
Backfill Soil ◽  
Load Cells ◽  
Set Up ◽  
Wall System

The paper presents a one-meter-height rigid facing panel, supported rigidly at the top and bottom to simulate nonyielding retaining wall system. A set of load cells is used to measure the horizontal force at the top and bottom of the facing panel, which is converted to equivalent horizontal earth pressure acting at the back of the wall. Another set of load cells is used to measure the vertical load at the bottom of the wall facing, both at the toe and the heel. Uniformly graded sand was used as backfill soil. The measured wall responses were used to calibrate a numerical model that used to predict additional wall parameters. Results indicated that the measured horizontal earth force is about three times the value calculated by classical at-rest earth pressure theory. In addition, the location of the resultant earth force is located closer to 0.4 H, which is higher compared to the theoretical value of H/3. The numerical model developed was able to predict the earth pressure distribution over the wall height. Test set up, instrumentation, soil properties, different measured responses, and numerical model procedures and results are presented together with the implication of the current results to the practical work.

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.

Research on Calculation Formula of Retaining Wall for Structural Reliability Program Design

2013 ◽  
Vol 275-277 ◽  
pp. 1154-1157
Author(s):  
Yun Lian Song ◽  
Si Li ◽  
Jian Ran Cao
Keyword(s):  
Safety Factor ◽  
Structural Reliability ◽  
Program Design ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Wall Structure ◽  
Active Earth Pressure ◽  
Material Parameters ◽  
Simplified Formula

Stability problem of gravity retaining wall structure was researched, and a simplified formula of the active earth pressure Ea was turned out for the convenience of the program design. The anti-slide safety factor K0 and anti-overturning safety factor Kc were derived based on different positions of slip plane of retaining wall. This work is the basis of the reliability calculating and program design, for these formulas must be used in anti-slide and anti-overturning safety failure mode in program compiling. On the basis of the known parameters such as wall type, wall dimensions, material parameters, external load, and so on, the program can automatically calculate K0 and Kc, their corresponding failure probability Pf and reliability index β can easily be calculated in later analysis. The research content provide a convenient calculation method, which is used to calculate the Ea and K0 and Kc and Pf and β of the actual retaining walls engineering.

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.

scholarly journals Multi-Criteria Parametric Verifications for Stability Diagnosis of Rammed-Earth Historic Urban Ramparts Working as Retaining Walls

2021 ◽  
Vol 11 (6) ◽  
pp. 2744
Author(s):  
Álvaro R. Serrano-Chacón ◽  
Emilio J. Mascort-Albea ◽  
Jacinto Canivell ◽  
Rocío Romero-Hernández ◽  
Antonio Jaramillo-Morilla
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
International Committee ◽  
Lateral Earth Pressure ◽  
Research Sector ◽  
Overall Stability ◽  
Urban Contexts ◽  
And Control

Institutions such as ICOFORT (International committee on fortifications and military heritage) encourages the development of diagnosis strategies for the conservation and maintenance of historic earthen walls as highly necessary. Thus, it is important to be aware of the conditions in urban contexts, where the deterioration can be more aggressive and the risk of damage increases. Despite this, there are many strategies of constructive diagnosis for these kinds of monuments, but not many of them are concerned with the structural assessment of situations in which the ramparts work as a retaining wall in an unforeseen way. The medieval ramparts of Seville (Spain) are shown as a completely representative case study of the above-mentioned situation. In the research sector, the monument resists the lateral earth pressure developed by the new difference in height at both sides of the wall. Based on the limited states principle and on different international codes formulation, a tool was programmed to carry out automatic calculations to verify the case study’s overall stability conditions using standard sections. The obtained results were based on the overturning, bearing, and sliding overdesign factors (ODF) and determined a stable situation that could be at risk because of changes in the surrounding such as, excavations or the movements of the ground water table, or seismic events. Thus, the need and usefulness of strategies and control instruments that should be integrated into heritage intervention projects have been proved.

scholarly journals Behaviour of Retaining Wall Founded on Collapsible Soil – A Prototype Laboratory Study

2014 ◽  
Vol 7 (3) ◽  
pp. 1-24
Author(s):  
Safa Hussain Abid Awn ◽  
Waad Abdulsattar Zakaria
Keyword(s):  
Retaining Wall ◽  
Soil Layer ◽  
Retaining Walls ◽  
Wall Structure ◽  
Prototype Model ◽  
Cement Dust ◽  
Collapsible Soil ◽  
Settlement Behavior ◽  
Backfill Soil ◽  
Gypseous Soil

Retaining walls may be required in a location where gypsum may present in soil in large percentages .The behavior of retaining walls on ordinary soils is well known but the behavior of retaining walls resting on gypseons soils may be not well understood as the case of ordinary soils.In this study it is intended to reflect the behavior of gravity retaining wall resting on collapsible soil. And to do so a small prototype model (600mm*500mm*200mm) is used with soil mixed in presumed percentages with different gypsum percentages (5%, 20%, 30%, 50%). In addition to a model with 30% gypsum and treated with 2.7% Cement dust mixed with soil founded retaining wall structure. After preparing the foundation gypseous soil, a small glass made retaining wall filled with sand, which represent gravity wall, is put over such bed and backfilled with ordinary sandy soil. Dial gauges are placed to side and top of wall to measure the rotation settlement behavior and collapse of system. 4kPa stress are applied to backfill soil as to accelerate collapse with leaching process commenced. Data are recorded and analyzed completely, which shows the behavior of such structures embedded with different gypsum content.The improvement in rotation settlement and collapse for the retaining wall model reaches more than 89%, was gained after treating the embedded gypseous soil layer, with 2.7% cement dust.

scholarly journals Effects of Geofoam Panels on Static Behavior of Cantilever Retaining Wall

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Navid Hasanpouri Notash ◽  
Rouzbeh Dabiri
Keyword(s):  
Numerical Study ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Expanded Polystyrene ◽  
Buffer System ◽  
Static Behavior ◽  
Static Loads ◽  
Static Performance ◽  
Cantilever Retaining Walls ◽  
Better Than

Geofoam is one of the geosynthetic products that can be used in geotechnical applications. According to researches, expanded polystyrene (EPS) geofoam placed directly against a rigid retaining wall has been proposed as a strategy to reduce static loads on the wall. This study employed a finite difference analysis using a 2-D FLAC computer program by considering yielding and nonyielding states for retaining walls to explore the effectiveness of geofoam panels in improving the static performance of cantilever retaining walls. Retaining walls at heights of 3, 6, and 9 meters and geofoam panels with densities of 15, 20, and 25 (kg/m3) at three relative thicknesses of t/H = 0.05, 0.2, and 0.4 were modelled in this numerical study. In addition, the performance of the double EPS buffer system, which involves two vertical geofoam panels, in retaining walls’ stability with four panel spacing (50, 100, 150, and 200 cm) was also evaluated in this research. The results showed that use of EPS15 with density equal to 15 (kg/m3) which has the lowest density among other geofoam panels has a significant role in reduction of lateral stresses, although the performance of geofoam in nonyielding retaining walls is better than yielding retaining walls.

Performance of Back-to-Back Geogrid Reinforced Soil Retaining Walls for Railways during Service

2021 ◽  
pp. 036119812110242
Author(s):  
Guangqing Yang ◽  
Yunfei Zhao ◽  
Zhijie Wang ◽  
He Wang
Keyword(s):  
Retaining Wall ◽  
Good Condition ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Reinforced Soil ◽  
Vertical Stress ◽  
Peak Strain ◽  
Lateral Earth Pressure ◽  
Reinforced Retaining Wall ◽  
Soil Retaining Walls

To investigate the performance of a reinforced soil retaining wall during service for a passenger-dedicated railway, long-term remote observation testing of the back-to-back geogrid reinforced retaining wall (BBGRSW) of Qing-Rong passenger-dedicated railway in Shandong Province was conducted for 60 months. The performance of the reinforced retaining wall was investigated after construction, and the lateral earth pressure of the reinforced soil wall was analyzed. The vertical stress on the wall and tension on the geogrid were measured using pressure cells and flexible deformation gauges, thereby resulting in the distribution of data and changes in the service period. The test results show that the pressure and deformation of the wall are almost stable. It was determined that the lateral earth pressure on the back of the wall panel was approximately 119.2% of the completion time during the 60 months after construction. The vertical stress on the reinforced soil retaining wall remained approximately stable 60 months post-construction. The maximum strain of the measured geogrids accounted for less than 30% of the peak strain. Moreover, the deformation of the wall was relatively small, which indicated that both sides of the wall remained in good condition. These research results can serve as a reference for the design optimization of reinforced soil retaining walls for high-speed railways.

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.

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