APPLICATION OF LANDSLIDE POSSIBILITY INDEX (LPI) SYSTEM ON ROCK SLOPES OF AL-SALMAN DEPRESSION, SOUTHWEST SAMAWA REGION, SOUTH IRAQ

Abstract

Landslide probability along the rock slopes and their hazards along the edges of Al-Salman Depression, 130 Km southwest of Samawa city, south Iraq was evaluated with Landslide Possibility Index System (LPI). The application of this system is based on field observations and measurements only, by considering ten characteristic features of the slopes and their rock forming.Only four sites of rock slopes were studied along the edges of Al-Salman Depression, where some rock slopes failures have occurred. The four studied sites comprise the rock slopes of exposures of Dammam Formation (Middle Eocene), which consists of alternations of white, grey and yellowish grey Nummulitic limestone. They are strong (rock material strength between 50 – 100 MPa), moderately weathered, medium to very thickly bedded and widely to very widely spaced joints. The joints apertures range between (0 – 30) cm, with tough and moderately weathered surfaces. The filling materials are soft, clayey and silty sand.The results of LPI calculations showed that the sites 1, 2 and 3 are of Very Low LPI values, whereas the site-4 has Low LPI value, because the slope height factor was estimated as high. Accordingly, the studied rock slopes in sites 1, 2 and 3 have Low Hazard categories, whereas the site-4 has Moderate Hazard category.