SLOPE STABILITY STUDY ALONG ABBOTABAD – NATHIAGALI ROAD

Abstract

Life and property of the inhabitants of Galiat Area are threatened by various natural hazards like earthquakes, flash floods and landslides etc. Amongst these, the landslides and related failure processes are the most damaging ones because of the geologically poor/fragile nature of these mountains. Fast expanding population and unchecked deforestation have severely disturbed the fragile natural equilibrium of Galiat Area. After widening and improvement project of road Abbotabad-Nathiagali-Barian the existing hill slopes have disturbed. The disturbance caused to the strata is causing frequent slope failure along the road. This study investigates the stability of slopes along road Abbotabad-Nathiagali, 35 km stretch, and suggests remedial measures to combat these landslides. The road has been divided into four zones based on slope stability failure potential. Detailed study on two typical representative sites of different zones is carried out. Field and laboratory investigations are performed to identify soil/rock strata and surface/subsurface drainage. Relevant field tests are performed to find in-situ strength properties of soil/rock and detailed laboratory testing is done to determine the strength properties of soil/rock samples under simulated conditions. The effect of typical climatic/environmental condition has also been incorporated in the study. Based on the material properties and the survey conducted, the computer softwares (GEO-SLOPE Office, Roclab and Plane Failure Analysis) were used for modeling and analysis of slopes. Proper slope formation, benching, drainage control, rocks scaling techniques are evaluated for slope stabilization along Abbotabad-Nathiagali Road. Furthermore, stabilization measures like design/construction of hydrological structures, breast walls, retaining walls and reduction of slope face angles are also evaluated. Finally the slopes were analyzed for the effects of the recommended solutions. Apart from the above mentioned suggested measures a need has been felt to enhance the awareness/understanding of the problem among locals, government/semi - government and non government organizations.