雅砻江锦屏一级水电站坝址区实测地应力与重大工程地质问题分析

本文对雅砻江锦屏一级水电站坝址区Ⅱ1-Ⅱ1及其前后剖面实测地应力进行了系统整理分析。分析结果表明:在相同的水平和垂直埋深条件下左岸坡角应力大小较右岸坡角小,这主要是由边坡岩体结构确定的;左岸导流洞开挖过程中在应力大小较右岸低的情况下出现坍塌工程地质问题也与左岸边坡岩体结构有关,而非岩爆等诱发。另外对左岸岩体深部裂缝在已有研究成果的基础上从应力集中、能量积累角度初步提出了新的边坡变形破坏方式,并从岩体结构和地应力大小方面对锦屏一级水电站工程建设过程中左、右岸应注意的工程地质问题提出了初步建议。

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.