Geotechnical characterisation and 2D soil cross-section model development in the Kashmir Basin

Abstract

An integrated analysis of the surface geology with geotechnical parameters of soils within the Kashmir Basin has been presented in this study. Spatial distribution maps of soil properties were prepared using an extensive database of Standard Penetration Test (SPT) reports at ~ 700 sites collected from geotechnical consultancies. The SPT N is high (~ 10–50) in the stiff, dry Pleistocene Karewas and low (< 20) in saturated Recent Alluvial deposits of the Jhelum River. These sedimentary deposits show a low plasticity index (< 17%) as well as the presence of stable clay minerals. The compression index is lower for Karewas (0.08–0.27) than for alluvium (0.16–0.36) indicating higher settlement hazard in the latter. Geological-cum-geotechnical cross-sections along seven transverse and five longitudinal transects were also developed. As an application of this study, the bearing capacity estimates, along with the liquefaction susceptibility map of the soils in the urban area of Greater Srinagar are presented. The alluvial floodplains are revealed to be critical in terms of low ultimate bearing capacity (< 300 kPa) as well as high liquefaction susceptibility (L_S > 0.8). On the other hand, Karewas show good bearing capacity (> 300 kPa) and medium liquefaction susceptibility (L_S 0.5–0.8). Based on these geotechnical aspects, Karewa highlands were found to be the most suitable for the expansion of the city and its future urbanisation. The results of this study are aimed to assist civil engineers in the proper design of structures, especially foundations, as well as to support urban planners in creating policies for town planning and expansion strategies in Kashmir.