Abstract:

Jinping first stage hydropower station was taken as the research area to study the stress field characteristics of a valley slope with complex geological structure in high geo-stress area. According to the analysis on Jinping valley stress field features, the valley slope stress was classified into four zones， namely，the stress-releasing zone, stress-interim zone, stress-concentrating zone and stress-stable zone. The tectonic stress and the morphology of valley shape were two important factors that cause high stress at the bottom of valley. The faults in valley significantly influence the stress field characteristics. The valley stress was more easily unloaded through the fault tending outward, which was one of the reason for the unloading limitation altitude was lower in left bank than right bank and deep unloading zone in left bank slope. The slope range influenced by geo-stress state adjustment during the river cutting was wider in right bank than in left bank. The rapid unloading because of river rapid cutting was one of the reasons that induced the deep cracks in Jinping.

Key words: Jinping first stage hydropower station, valley stress field, high geo-stress, complex geological structure, stress