General geology and soil mechanics analysis of highly to completely weathered rock along KM 118.3 - 123.9 East-West Highway

The study area is situated 10 km from Jeli town and 90 km from Kota Bharu. This area is bounded by the latitude 5° 40' 42.63" N until 5° 43' 15.00" N and between 101° 47' 45.00" E until 101° 50' 26.05" E. This research focuses on the general geology, soil mechanic analysis, and slope failure survey in zones of highly to completely weathered rock (grade IV-V) along KM 118.3 - 123.9 East West Highway. Petrography study show that the medium-grained biotite granite dominantly across the study area with gneiss in the SW of study area. Slope failure survey was done and a total of 22 samples were taken systematically across the study area. From the survey, the slope failure in the study area categorized by raveling, erosion, planar, and wedge. The factor that caused the slope failure is from geological aspects and physical aspect. The texture sample of soils is classified as coarse grain soils (more than 50% are coarse grain). These soil samples indicates a medium plastic ranges from 15% - 30 %. Results of the soil mechanic analysis show that the soil can be classified into SP, Poorly-graded sand, SP, Poorly-graded sand with gravel, SP-SC, Poorly-graded sand with clay or silty clay, SP-SM, Poorly-graded sand with silt, SW-SC, Well-graded sand with clay and gravel (or silty clay & gravel). Based on the soil mechanics parameters, presence of clay that found in the soil samples increase the plasticity index and contribute towards slope failure.