No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effectiveness of Geocell in Improving the Dynamic Soil Properties for Machine Foundation
ResearchGate has not been able to resolve any citations for this publication.
This manuscript evaluates the effect of various influencing factors on the vibration mitigation efficiency of geocell-reinforced foundation beds. Parameters investigated include the width of geocell, depth of placement of geocell below the footing, depth of embedment of footing, infill materials, and the dynamic force level of the excitation. The effect of aforesaid parameters was studied by performing field vibration tests over the reinforced test beds of 3.6 m × 3.6 m × 1.2 m. To understand the vibration isolation efficacy, different vibration indicators, viz., displacement amplitude, peak particle velocity (PPV), and peak acceleration were evaluated. From the results, reinforcing the soil bed with geocell was found to be a worthwhile approach to control the vibration parameters. For achieving the maximum isolation, the optimum width and depth of placement of geocell were found to be 5B and 0.1B respectively. At its optimum width and depth of placement, the peak particle velocity was reduced by 50%. Similarly, it was observed that the 53% drop in the peak displacement amplitude of the foundation bed. Vibration parameters in the geocell reinforced case were found attenuated with the increase in footing embedment and modulus of infill material. On the other hand, the vibration parameters of the unreinforced and geocell reinforced cases were amplified distinctly due to the increase in dynamic excitation.
Use of the geosynthetics to strengthen the soil is one of the highly desirable techniques under static and dynamic loads. The present study describes the experimental and numerical studies performed on the geosynthetic reinforced subgrade subjected to repeated vehicle loads. The cyclic plate load tests were conducted on the sand subgrade reinforced with planar and 3D geosynthetic reinforcements. The vehicle load was simulated by applying a repeated load of magnitude 275 kPa with 1 Hz frequency on the reinforced subgrade. Results of the experimental investigations revealed that the performance of the subgrade soil improved significantly in the presence of reinforcements. The estimated parameters illustrated the three-fold reduction in settlement of the subgrade in the presence of reinforcement. Further, the heaving of the subgrade soil was found completely arrested with the use of geosynthetic reinforcement. The three-dimensional geocell reinforcement performed effectively as compared to planar geogrids under dynamic load. The measured pressure values at different depth demonstrated a significant reduction in the pressure in the presence of reinforcements. Besides, numerical simulations were performed using PLAXIS2D to understand pressure and settlement distribution patterns in the reinforced subgrade. In overall, a good agreement was observed between numerical and experimental results.
This paper describes the potential use of geocell reinforcement in mitigating the traffic
induced vibration. The vibration caused by the vehicular movement was simulated over
the unreinforced and geocell reinforced sections using a mechanical oscillator. The
displacement amplitude and peak particle velocity were measured to understand the
vibration mitigation efficacy of geocell. The effect of depth of placement of geocell
on the mitigation of vibration parameters was studied. The inclusion of geocell was
found effective in reducing the induced vibration based on the experimental results.
The vibration mitigation efficacy of geocell was improved significantly at the shallow
depth of placement of geocell mattress. The improvement in elasticity of the subgrade
was observed maximum when the geocell was placed at a depth of 0.1B from the
ground surface. Further, analytical and numerical approaches were used to predict the
displacement amplitude vs. frequency response of reinforced soil sections. FLAC3D was
used for performing the numerical investigation. The geocell was modeled according to
its honeycomb shape to acquire the accurate response of geocell reinforced section.
Whereas, mass spring dashpot analogy was followed for the analytical evaluation. In
overall, the amplitude response predicted from the numerical and analytical studies were
found to be in good agreement with the experimental results.
This paper investigates the isolation efficacy of geocell-reinforced foundation beds infilled with different materials through a series of block resonance tests. The geocell made with a novel polymeric alloy (NPA) was used in the experimental investigation. In total, five different cases — namely, unreinforced, geocell-reinforced silty sand, geocell-reinforced sand, geocell-reinforced slag, and geocell-reinforced aggregate — were considered. Presence of the geocell has resulted in improvement of screening efficacy of the foundation bed regardless of the infill material. The displacement amplitude of the geocell-reinforced bed cases was reduced by 68%, 64%, 61%, and 59%, respectively, for aggregate, slag, sand, and silty sand infill cases as compared to the unreinforced condition. Maximum isolation efficiency was observed in the presence of aggregate, among the four different infill materials. In the presence of aggregate infill, the shear modulus of the foundation bed was improved by 150%. Similarly, the peak particle velocity and peak acceleration were reduced by 57% and 48%, respectively. Further, the efficacy of mass spring dashpot (MSD) analogy was studied in predicting the frequency–displacement response of different reinforced cases. From the analytical study, a significant improvement in damping ratio of the foundation bed was observed in the presence of geocell reinforcement.
This paper presents the results of laboratory model tests and numerical studies conducted on a square footing resting on geocell reinforced sand and clay beds. Using suitable scaling considerations, a model footing size was arrived from the prototype raft foundation. Commercially available geocells made up of polyethylene having an equivalent pocket diameter of 0·25 m and aspect ratio of 0·6 were used in the experimental investigation. Clean sand was used to fill the geocell pockets in both sand and clay bed tests. Test results of unreinforced, geocell reinforced, and geocell reinforced with additional planar geogrid at the base of the geocell cases are compared separately for sand and clay beds. Results reveal that the use of geocell increases the ultimate bearing capacity of the sand bed by 2·4 times and clay bed by 3·2 times. Provision of the planar geogrid at the base of the cellular mattress arrests the surface heaving and prevents the rotational failure of the footing. Moduli of subgrade reaction values indicate that the contribution of the geocell reinforcement exists even at very low settlements. Using the concept of equivalent composite model, the three-dimensional nature of the geocell is numerically simulated in the fast Lagrangian analysis of continua in 2D (FLAC2D). Experimental and numerical results are in good agreement with each other.
The manuscript is aimed to provide numerous insights into the behavior of the geocell reinforced bed subjected to a vibration load. Vibration propagation mechanism, displacement, and stress response of geocell reinforcement have been described. Two different cases, namely, unreinforced and geocell-reinforced beds subjected to a vertical mode dynamic excitation have been analyzed using the finite-difference package FLAC 3D . Initially, the developed numerical model was validated with the results of field vibration test. Results revealed that the inclusion of the geocell reinforcement in the foundation bed significantly improves vibration isolation efficacy. The foundation bed strain due to vibration loading was reduced by 67% due to the provision of geocell reinforcement. Based on the observed wave propagation behavior of the geocell reinforced bed, a mechanism was proposed to quantify the diffraction angle and the dispersion distance of induced vibration. The diffraction angle was found to vary between 50° to 63° in the presence of a geocell mattress. The dynamic stress factor calculated based on the hoop stress theory was found to vary between 1.5 to 2 for geocell with different infill materials. Further, parametric analysis was performed to understand the effect of geocell geometry on the peak particle velocity (PPV) response of the reinforced bed.
This paper investigates numerically the potential use of cellular confinement systems in isolating the machine induced vibrations. The numerical analysis was carried out using the three dimensional explicit finite difference package FLAC3D. Primarily, the numerical model was validated with the results of field resonance tests, performed on the foundation beds reinforced with and without cellular confinement systems. The 3D cellular confinement was simulated using two techniques, namely, Equivalent Composite Approach (ECA), and Honeycomb Shape Approach (HSA). The isolation efficiency of the confined cell was determined in terms of the reduction in displacement amplitude, peak particle velocity, and the improvement in elasticity of the foundation bed. From the results, 56% reduction in displacement amplitude was observed in the presence of geocell reinforcement. Similarly, 42% change of resonant frequency was observed as compared to the unreinforced condition. The elasticity of the foundation bed was improved by 102% with the provisions of geocell. Further, it was noticed that the modelling of geocell through the HSA approach provided the accurate prediction of the experimental results. With the help of HSA technique, the effect of confinement area and the height of geocell in reducing the amplitude of vibration was investigated. Further, the parametric study was conducted to investigate the effect of different geocell properties on the dynamic behaviour of reinforced foundation bed. The parametric study results revealed that the geocell modulus and the interface friction angle directly influence the performance of geocell reinforced bed under dynamic loading condition.
The manuscript describes the results of large scale field tests and numerical studies conducted on geosynthetics reinforced soil beds supporting model machine foundation. A series of vertical mode block resonance tests are conducted over a rigid concrete footing resting on different reinforced soil conditions. The tests are performed in a test pit of size 2 m × 2 m × 0.5 m using a concrete footing of size 0.6 m × 0.6 m × 0.5 m. Four different conditions, namely, unreinforced, single layer geogrid reinforced, two layer geogrid reinforced and geocell reinforced conditions were considered. The tests are performed under six different dynamic force levels using a Lazen type mechanical oscillator. In total, 38 number of field tests are conducted. The dynamic response is studied in terms of reduction in resonant amplitude, peak particle velocity (PPV) and improvement in dynamic properties of the soil. Experimental results revealed that the displacement amplitude of vibration significantly reduced in the presence of geosynthetics. The maximum reduction is observed in the presence of geocell reinforcement as compared to the other conditions. In the presence of geocell reinforcement, resonant amplitude is decreased by 61% and the natural frequency of the soil system is increased by 1.38 times as compared to the unreinforced condition. In addition, the geocell reinforcement found to reduce the PPV by 48% at a distance of 0.5 m from the footing face. The elastic uniform compression of the foundation bed is improved by 91% in the presence of geocell reinforcement. Further, the experimental results are validated with the numerical studies conducted by using finite difference package FLAC3D. The encouraging agreement in the dynamic behavior of reinforced soil is observed between the numerical and experimental studies. The numerical results revealed that the lateral spreading of vibrations is significantly controlled in the presence of geocell reinforcement.
The present study deals with model plate load tests conducted on geocell reinforced soft clay beds to evaluate the effect of infill materials on the performance of the geocell. Commercially available Neoweb geocells are used in the study. Three different infill materials namely aggregate, sand and local red soil were used in the study. The load carrying capacity of the geocell reinforced bed (as compared to an unreinforced bed) was found to be increased by 13 times for the aggregate infill, 11 times for the sand infill and 10 times for the red soil infill. Similarly the reduction in the settlement was in the order of 78%, 73% and 70% aggregate, sand and the red soil infill materials respectively. Results suggest that the performance of the geocell was not heavily influenced by the infill materials. Further, numerical simulations were carried out using FLAC2D to validate the experimental findings. The results from numerical studies are in reasonably good agreement with the experimental findings. The outcome of this work is successfully implemented in the construction of the geocell foundation to support a 3 m high embankment in the settled red mud in Lanjighar (Orissa) in India.
Numerical analysis of machine foundation resting on the geocell reinforced soil beds. Resistivity correlation with SPT-N and shear wave velocity of Patna Soil in India view project vibration isolation view project
- V Hasthi
- A Hegde
Hasthi V, Hegde A (2018) Numerical analysis of machine foundation resting on the geocell
reinforced soil beds. Resistivity correlation with SPT-N and shear wave velocity of Patna Soil
in India view project vibration isolation view project. [Online]. Available https://www.resear
chgate.net/publication/329451307
Experimental and theoretical investigations on geocell-supported embankments
- G M Latha
- K Rajagopal
- N R Krishnaswamy
Latha GM, Rajagopal K, Krishnaswamy NR (2007) Experimental and theoretical investigations
on geocell-supported embankments. https://doi.org/10.1061/ASCE1532-364120066:130