Browsing by Author "Jayamohan, J."

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Behaviour of Prestressed Geosynthetic Reinforced Granular Beds Overlying Weak Soil
(2014) Shivashankar, R.; Jayamohan, J.
This paper presents an analytical model for predicting the improvement in bearing capacity of geosynthetic reinforced granular beds overlying weak soil due to prestressing the reinforcement. A punching shear failure mechanism is envisaged in the analytical model. Results obtained from a series of laboratory scale bearing capacity tests and finite element analyses are used to validate the model. The addition of prestress to the reinforcement results in significant improvement of the settlement response and the load-bearing capacity of the foundation. The parameters studied are strength of underlying weak soil, thickness of granular bed, magnitude of prestressing force, direction of prestressing forces, type of reinforcement and number of layers of reinforcement. The bearing capacity ratios (BCRs) values predicted by the analytical model are found to be in good agreement with the experimentally obtained BCR values. Finite element analysis are carried out using the FE program PLAXIS to study the effect of prestressing the reinforcement. Results obtained from finite element analysis are found to be in reasonably good agreement with the experimental results. © 2013 Indian Geotechnical Society.
Behaviour of prestressed reinforced foundation beds overlying weak soil
(2014) Shivashankar, R.; Jayamohan, J.
Geosynthetics in foundation beds demonstrate their beneficial effects only after considerable settlements, since the strains occurring during initial settlements are insufficient to mobilize significant tensile load in the geosynthetic. Prestressing the reinforcement is a promising technique to overcome this shortcoming. This paper presents results from a series of laboratory scale bearing capacity tests carried out on model square footings to investigate the improvement in bearing capacity of geosynthetic reinforced foundation bed overlying weak ground due to prestressing the reinforcement. Prestressing the reinforcement in foundation bed results in significant improvement of bearing capacity of weak soil. A numerical model is suggested to predict the improvement in bearing capacity of footings with all the three cases - i.e., Granular Bed (GB), Reinforced Granular Bed (RGB), or Prestressed RGB on weak soil - by assuming a punching shear mechanism. These predictions are compared with laboratory scale experimental results. The proposed model is found to give good prediction of bearing capacity improvement. Finite element analyses are carried out using the FE program PLAXIS to study the effect of prestressing the reinforcement. Results obtained from finite element analyses are found to be in reasonably good agreement with the experimental results. � ASCE 2014.
Behaviour of prestressed reinforced foundation beds overlying weak soil
(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2014) Shivashankar, R.; Jayamohan, J.
Geosynthetics in foundation beds demonstrate their beneficial effects only after considerable settlements, since the strains occurring during initial settlements are insufficient to mobilize significant tensile load in the geosynthetic. Prestressing the reinforcement is a promising technique to overcome this shortcoming. This paper presents results from a series of laboratory scale bearing capacity tests carried out on model square footings to investigate the improvement in bearing capacity of geosynthetic reinforced foundation bed overlying weak ground due to prestressing the reinforcement. Prestressing the reinforcement in foundation bed results in significant improvement of bearing capacity of weak soil. A numerical model is suggested to predict the improvement in bearing capacity of footings with all the three cases - i.e., Granular Bed (GB), Reinforced Granular Bed (RGB), or Prestressed RGB on weak soil - by assuming a punching shear mechanism. These predictions are compared with laboratory scale experimental results. The proposed model is found to give good prediction of bearing capacity improvement. Finite element analyses are carried out using the FE program PLAXIS to study the effect of prestressing the reinforcement. Results obtained from finite element analyses are found to be in reasonably good agreement with the experimental results. Â© ASCE 2014.
Effects of prestressing the reinforcement on the behavior of reinforced granular beds overlying weak soil
(Elsevier Ltd, 2014) Shivashankar, R.; Jayamohan, J.
The effects of prestressing the reinforcement on the strength improvement and settlement reduction of a reinforced granular bed overlying weak soil are being investigated through a series of laboratory scale bearing capacity tests. The influences of parameters such as strength of underlying weak soil, thickness of granular bed, magnitude of prestressing force, direction of prestressing forces and number of layers of reinforcement are being examined. Finite element analyses are carried out using the FE program PLAXIS to study the effect of prestressing the reinforcement. Results obtained from finite element analyses are found to be in reasonably good agreement with the experimental results. © 2013 Elsevier Ltd.
Influence of prestress on the behaviour of footings resting on reinforced foundation beds
(Korean Geosynthetics Society, 2018) Jayamohan, J.; Shivashankar, R.; Anandan, A.
Geosynthetics in foundation beds demonstrate their beneficial effects only after considerable settlements, since the strains occurring during initial settlements are insufficient to mobilize significant tensile load in the geosynthetic. Prestressing the reinforcement is a promising technique to overcome this shortcoming. This paper presents results from a series of finite element analyses carried out to investigate the improvement in bearing capacity of a footing resting on geogrid reinforced foundation bed overlying weak ground due to prestressing the reinforcement. The results of finite element analyses are validated by carrying out a series of laboratory scale loading tests. The parameters varied are magnitude of prestress, relative density of foundation bed etc. The effects of prestressing on the interface shear strength between geogrid and granular soil are studied by carrying out large scale direct shear tests in a shear box of dimensions 300 x 300 x 200 mm. It is observed that the bearing capacity and settlement behaviour of footings can be considerably improved by prestressing the geosynthetic reinforcement in the foundation bed. The interface shear strength between geogrid and granular soil is considerably influenced by the magnitude of prestress. Â© Â© 11th Inter. Conf. on Geos. 2018, ICG 2018. All rights reserved.
Some studies on engineering properties, problems, stabilization and ground improvement of lithomargic clays
(Southeast Asian Geotechnical Society seags@ait.ac.th, 2015) Shivashankar, R.; Ravi Shankar, A.U.; Jayamohan, J.
The study area for this paper is coastal Karnataka in India. The area has laterites and lateritic soils, and also a large number of sporadic lateritic hillocks. The soil stratification mainly consists of lithomargic clay sandwiched between the weathered laterite at top and the hard granitic gneiss underneath. Quite often the top laterites are removed in this area for use as bricks for construction purposes, thus exposing the underlying lithomargic clay. This coastal area receives copious amount of rainfall and a lot of developmental activities are taking place. These lithomargic clays, locally called as 'shedi soils' are also used as fill material in low lying areas, very often adjacent to water bodies. These soils behave as dispersive soils and are also highly erosive. A lot of engineering problems - such as foundation problems, subgrade problems, erosion and slope stability problems are being faced due to the presence of these shedi soils. Some laboratory studies on the engineering and strength properties of these lithomargic clays and stabilized soils, Ground Improvement on shedi grounds are made and reported.