The frequent collapses of banks have been plaguing Sanmenxia reservoir since it ran and started to store water in September of 1960. The average volume of the collapse is 0. 05~0. 07 billion m3 per year. It shows that the major reasons of the collapses of the bank are the influence of the geologic surroundings and the various hydraulic conditions and their variation character. The degree of the collapse is apparently different because of various terrain? geomorphic unit and specificity of rock in different geology surroundings. The loess platform is the extremely strong collapse segment

Yellow River terrace H is the moderately strong collapse segment and Yellow River terrace I is the strong collapse segment. The key factors which cause collapse are precipitation

surface water and groundwater. The extent and the manner of reservoir-bank collapses are different with diverse hydraulic conditions and their variations. Finally

it demonstrates that the preventive and the cure of collapse should be performed in nature and surface. The surface cure mainly includes carrying necessary reinforcement

shoring

lines and other defending projects into practice according to status of reservoir-bank collapse. The essential cure mainly performs general measures with reasons which cause collapse and with characters of collapse in different geology conditions and with hydraulic conditions. And adjust measures to local conditions and carry measures to local damages.