Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
2 results
Search Results
Item Near-surface seismic refraction tomography and MASW for site characterization in Phuentsholing, Bhutan Himalaya(Springer Nature, 2021) Sarkar, R.; Kolathayar, S.; Drukpa, D.; Choki, K.; Rai, S.; Tshering, S.T.; Yuden, K.It is essential to understand the soil characteristics of the subsurface layers for any engineering construction. In difficult terrains like hilly areas, conventional methods of investigation are expensive and difficult to conduct. It calls for nondestructive testing methods to get reliable estimates of subsurface properties. In the present study, seismic refraction tomography (SRT) technique and multichannel analysis of surface waves (MASW) methods were carried out along five selected profiles in Phuentsholing region of Bhutan Himalaya. The profile length ranges from 37 to 81.5 m, and depth of imaging down to 10 m. While the SRT data imaged the P-wave velocity (Vp) structures, the MASW imaged the shear wave velocity (Vs) structures. The P-wave images provide a fair knowledge of geological layers, while the MASW images provide S-wave velocity structures (Vs). These results are useful to estimate soil parameters, like the density, Poisson’s ratio, Young’s modulus, shear modulus, N-value and the ultimate bearing capacity. The seismic images reveal the presence of sand, sandy clay, gravels and shale layers below the selected sites. Bhutan Himalayas being seismically vulnerable, the obtained results in terms of shear wave velocity were accustomed to categorize the sites as per NEHRP site classes, and a ground response analysis was performed to determine the reliable amplification factors. From the study, it is suggested that the engineering construction is feasible at all the sites except in one site, where an indication of saturated soil is observed which is vulnerable for liquefaction, and ground needs to be improved before construction at that site. © 2021, The Author(s).Item Deterministic seismic hazard analysis for Phuentsholing region of southern Bhutan considering local site effects(Springer Science and Business Media Deutschland GmbH, 2022) Sengupta, S.; Sarkar, R.; Kolathayar, S.; Drukpa, D.Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development of infrastructure over time, the safety of the residence and lifeline buildings becomes a matter of concern. Bhutan lies in the Himalayan mountain ranges, which is considered one of the most active regions for seismic events. The Indian seismic code, IS 1893-2016, has assigned Zone IV for the region, which signifies the large risk that exists for all the structures. Therefore, conducting a seismic hazard assessment for the site becomes extremely necessary before any major construction. The present study focusses to perform the deterministic seismic hazard analysis (DSHA) around certain points of interest in the town of Phuentsholing, in Bhutan. Furthermore, site-specific response spectra for Pipaldhara-1, Pipaldhara-2, Kabreytar-1, Kabreytar-2 and Phuentsholing town were plotted from the results of the DSHA. It is estimated that a peak ground acceleration ranging from 0.11 to 0.14 g can be anticipated at the level of bedrock in the study region. Response spectra were plotted for the ground level using appropriate soil-amplification coefficients, derived from the analyses in the DEEPSOIL program. © 2022, Springer Nature Switzerland AG.