THE INFLUENCE OF UNSTABLE SLOPES ON THE STABILITY OF MAKHOOL DAM – CENTRAL IRAQ

Abstract

Makhool dam (under construction, which is stopped neither to) is located on the Tigris River about 30 km northwest of Baiji town. The reservoir extends to Sharqat vicinity. The exposed rocks within the reservoir area belong to the Fatha and Injana Formations. The former consists of marl, claystone, limestone and gypsum in cyclic nature. Whereas, the latter consists of claystone, siltstone and sandstone, in cyclic nature too. The western limits of the reservoir are bounded by scarps which belong mainly to Makhool and Khanoogah anticlines. Major parts of these scarps suffer from unstable slopes, along them many mass movements are developed. Moreover, the scarps are potential areas for development of mass movements, which will increase after construction of the dam, due to major change in water level. This will consequently change the properties of the exposed rocks and soils in the banks of the reservoir. The expected mass movements will influence on the stability of the dam, especially if they took place together at once. The slopes and scarps of the western limits of the reservoir are divided into five zones. For each zone different characters are mentioned with estimating conditional and average probability of landslides occurrence. Moreover, unique terrain units are defined.