A Detail Analytical Study on Ground Response Analysis of Subgrade Soil under a Flexible Pavement

In Barasat, a long stretch of road exists between Champadali more and Kazipara more on which heavy traffic moves. Due to the previous mild earthquake in West Bengal, the road stretch under consideration experienced a mild ground response due to which some cracks developed resulting in the blockage of the normal traffic. Earthquake shake is the most significant and universally encountered problems in geotechnical earthquake engineering. Correspondingly, the aim is the evaluation of ground response or ground shake response. In this project a detail analytical study on ground response analysis of subgrade soil under a flexible pavement stretch between Champadali and Kazipara is elaborately discussed. Ground response analysis is used to predict site natural periods, assess ground motion amplification, provides ground motions for development of design response spectra, evaluate potential for liquefaction, and to determine the forces induced due to an earthquake which can lead to instability of earth and earth slopes. To estimate the ground response of soil one shall have correct soil model which represent its dynamic properties. For this purpose, field tests (SPT, Seismic down hole tests) and laboratory tests (cyclic triaxial test) will be carried out for soil sites from Barasat. Also 3D analysis is being done for the analysis. Using the laboratory and field test results, it is proposed to develop a model for dynamic deformation characteristics. Some case studies are being given here. The model proposed will be validated by applying recorded time history of bedrock and compares its free field response with the recorded free field time history. Also liquefaction assessment will be carried out using the site characteristics data and site response study results. The effects of soil strain, terrain properties, water table and earthquakes on Peak ground motion will be studied.