THE METHODOLOGY AND RESULTS OF SLOPE STABILITY STUDIES IN INDONES

Java is characterised by a central hilly to mountainous volcanic comprised of deeply weathered Quaternary ashes and tuffs resting relatively weak and unstable sedimentary sequence dominated by mudstones. The region is one of the most tectonically active in world. The paper describes research undertaken to develop a methodology to study existing road slopes and to recommend guidel to promote safe slope construction. The research was co-funded b the International Bank for Reconstruction and Development (IBRD) the Department for International Development (DfID) and carried o by staff of the Transport Research Laboratory (TRL) collaborating with staff of the Institute of Road Engineering (IRE) in Bandung, Indonesia. Existing slope data were reviewed but since they were diverse it was necesssary to devise a new data system. This is described in the paper and consisted of about 150 fields grouped 5 database files. Selected road sections in Java were then chose the basis of geology and terrain. About 40 sections, totalling 1100km of road, were investigated and detailed measurements made 500 individual slopes, mostly cuts. Road sections where failures occurred and others where no failures had occurred were compared. The data were analysed empirically to derive correlations between slope height and angle and the likelihood of failure for the rang materials occurring in Java. The paper discusses these results. knowledge gained can be used to improve the design procedures for road projects. For existing roads it can be used to improve maintenance treatments. (A) For the covering abstract see ITRD E106363.