Vertical stresses in soil below a three dimensional structure due to reinforced soil structure interaction

Abstract

Numerous problems in civil engineering involve interaction between the structures and the soil. This interaction plays a significant role in the response of a structure and may change the magnitude of displacements, stresses and other responses of a structure in comparison with the non-interactive analysis. In the non-interactive analysis, the structure is assumed to be resting on fixed supports and shall not undergo any relative motions. In Soil Structure Interaction (SSI) analyses, the displacements and stress resultants are found to deviate considerably from non-interactive analysis there by rendering the non-interactive analysis as unrealistic and it is absolutely necessary to consider SSI in the analysis and design of structures. In the present paper, the response of a three dimensional structure is studied in Reinforced Soil Structure Interaction (RSSI). RSSI refers to the interaction between the reinforced soil and the structure. Comparative numerical studies have also been carried out by using finite element analyses to study the effects of a 3D frame resting on unreinforced and reinforced soil by developing programmes, SSI-LIN, SSI-NLIN, RSSI-LIN and RSSI-NLIN for both the linear and non-linear analyses. SSI-LIN and RSSI-LIN are the programs developed to conduct linear analyses and SSI-NLIN and RSSI-NLIN are the programs developed to conduct nonlinear analyses. They are used to study displacements, stresses in soil and member end forces in the structure. The present paper discusses only the effects of SSI and RSSI analyses on stresses in soils. In this study, macro element approach is adopted as modelling the geogrid proves to be very difficult with apertures of size 33 × 25 mm. This is due to limitations of software and prolonged execution time. The vertical pressure at various points are not affected much in non-linear RSSI analysis compared to non-linear SSI. However there is reduction in longitudinal and transverse stresses in non-linear RSSI analysis compared to non-linear SSI. There is also a change in the pressure bulb below foundation level. Hence it is important to conduct RSSI studies. © 2020, Research Trend. All rights reserved.