AN ANALYSIS ON IN-SITU CRUSTAL STRESS MEASUREMENTS AND MAJOR ENGINEERING GEOLOGY ISSUES AT THE DAM SITE AREA OF JINPING FIRST STAGE HYDROPOWER STATION

This paper has systematicly managed and analysized the in-situ crustal stress measurements around the Ⅱ1~Ⅱ1 section at the dam site of Jinping first stage hydropower station. The results show that the geo-stress magnitudes at the right abutment slope foot are bigger than the ones at the left abutment slope foot at nearly same horizontal and vertical burying depths, which is controlled by rock mass constitution, and that the collapse engineering geology problem in the process of left abutment slope water diversion tunnelling at this crustal stress conditions is also related to the left abutment slope rock mass constitution, but not caused by rockbursts and so on. In addition, on the basis of all existed research achievements on deep fractures in the left abutment slope, a new model from geo-stress and strain energy enconcentrations is given to explain the deep fissures, and some suggestions on the possible engineering geology issues from rock mass constitution and geo-stress magnitudes are also given to pay much attention on the both abutment slopes in the hydropower station construction.