Stabilisation of Karewa Soil Using Pine Needles and Cement:An Experimental Study with Statistical Regression Analysis

Abstract

Karewas are unique but problematic soils in the Kashmir Valley, consisting of sand, silt, clay, and loessic sediment, with low shear strength and susceptibility to disturbances. This study investigates stabilising Karewa soils using pine needles and Ordinary Portland Cement (OPC).

Pine needles from Dabjan Shopian, Kashmir, were cut into 1 cm and 2 cm lengths, and OPC was added. Karewa soil samples were analysed for water content, plastic and liquid limits, specific gravity, optimum moisture content, maximum dry density, and soaked CBR.

Laboratory tests involved adding varying proportions of pine needles (0.5%, 1%, 1.5%, and 2%) and a constant cement content (0.5% by dry weight). These tests revealed that pine needles and cement significantly improved the soil's compaction and strength.

Multiple linear regression analysis showed that 56.3% of the variability in CBR could be explained by the predictors, with a significant positive relationship between the percentage of pine needles and CBR.

This study demonstrates that pine needles and cement can enhance Karewa soil's strength and stability, offering a sustainable solution for soil stabilisation in the Kashmir Valley.