ABSTRACT
This chapter presents a large slope failure with a volume of 10.6 × 104 m3 occurred on the left abutment of Manwan hydropower Project. It discusses geological condition, failure mechanics and simulation, and remedial words, lessons learned. The Manwan project is located on the Lancang river between Yunxian county and Jingdong county of Yunnan province. The project is composed of concrete gravity dam, spillway tunnel and powerhouse. The fresh rock of left bank slope is compacted without primary soft layers. A catastrophic landslide happened during the left abutment excavation of Manwan concrete dam on January 7, 1989 when the elevation went down from 1017 m to 911 m. Several engineering measures such as cutting slope, unloading, anti-sliding piles, and pre-stressed cables, shallow and deep drainage have been adopted to guarantee the stability after the landslide failures.
