官地水电站地下厂房区地应力测试与应用分析

Geostress Measurement and Application Analysis for Guandi Hydropower Plant's Underground Powerhouse

为了确定雅砻江官地水电站地下厂房区初始地应力场,并为厂房及洞室系统的优化布置提供依据,在地下厂房区6个部位各布置了一个钻孔,采用空心包体式钻孔应变解除法进行了三维地应力测量。测试结果表明:最大主应力量值为20~22MPa,属中高应力区,最大水平主应力方向在NW^NNW之间。最大水平主应力与地下洞室初期布置方向夹角近90,°不利于洞室围岩的稳定性。为此,从综合考虑地应力和地质构造条件的角度,提出了调整地下厂房布置方向的优化建议。

In order to determine the in - situ stress field of Guandi Hydropower Plant＇s underground powerhouse, situated on Yalong River, and to provide data for optimal arrangement of powerhouse and relevant tunnel system, three dimensional over - coring stress measurements using hollow inclusion tfiaxial gauge have been conducted in 6 boreholes at different location in the area of underground powerhouse. Results reveal that the stress level is qualified as middle to high with maximum stress magnitude of 20 ～ 22 MPa, the direction of maximum horizontal stress ：is at NW ～ NNW. The direction of maximum horizontal stress is nearly perpendicular to that of the powerhouse＇s initial arrangement axis, so it is unfavourable to the stability of surrounding rock mass. Therefore an improved arrangement scenario about adjusting the axis of underground powerhouse is thus proposed on basis of comprehensive consideration of initial stress and geo - structural conditions.