ENGINEERING GEOLOGICAL PROPERTIES AND STABILITY ANALYSIS OF MORAINE DEBRIS SLOPES IN PALONG RIVER DRAINAGE AREA ALONG SICHUAN-TIBET HIGHWAY

The Ranwu to Lulang section of Sichuan-Tibet highway locates in Palong River drainage area, north edge of eastern Himalayan structure junction. The tectonic activities are so strong that a large number of faults and folds are formed in the area. Under coupling of the endogenic and exogenic geological processes, there are many loose Quaternary deposits, and they are the main carrier of most geological hazards. Under the river cutting and construction of Sichuan-Tibet highway, many slopes are formed, especially moraine slopes. The particle size characteristic of moraine is different with other sediments, because of the particles distribution from clay to gravel and more coarse particles. The structure and mechanical features of the slopes are also different with other slopes because of particle size characteristics, and they are varied with the size scale. At the same time, the mechanical feature is affected by content and distribution of the different particles and age of moraine. This paper presents the surveyed results of some typical moraine slopes along the highway. A laser profiler and a total station were used in the topographical survey. It is obvious that the slopes are high and steep, but they are stable. Based on the limit equilibrium theory, themoraine high slopes are analyzed for their stabilities. And Different methods are used to analyze the stability of the slopes in natural state. At last, the stabilities of the slopes are estimated wuth the effect of earthquake.