摘要
周宁水电站在交通洞开挖过程中局部洞段发生了较强烈的岩爆。地下洞室和高压岔管、输水隧道设计及选择衬砌方式,需要查明原地应力状态。为此,采用水压致裂法在3个深钻孔中和岩爆部位进行了原位应力测量。结果表明,平面应力值随孔深增加呈线性增大;在岩爆和地下洞室附近,原位应力最大值为13～15 MPa,以水平挤压应力为主导,最大水平主应力方向为NW向。根据地应力测量资料和相关理论、判据分析认为:地下厂房长轴为NW向有利于围岩稳定;高压岔管和输水隧洞选用钢筋混凝土衬砌是可行的;发生局部岩爆,主要是由于隧道开挖围岩应力重新调整,在掌子面附近应力集中所致。
A strong rockburst took place at one part of transportation tunnel at Zhouning Hydropower station while excavation. Underground tunnel, high pressure bifurcated pipe, water inlet tunnel designing and their lining style need know crustal stress too. So stress measurement with hydraulic fracturing was adopted in 3 deep drillholes from surface and in the rockburst measuring point. The results indicated that planar stress increased linearity with the depth of drillholes, the maximal value of crustal stress was 13-15 MPa near the site of rockburst and underground tunnel with the dominant horizontal extrusion direction NW. Based on the data of crustal stress and interrelated theory and criterion, it concluded that, first, major axis at NW direction was the best to underground plant building抯 stability; secondly, reinforced concrete lining was practicable in high pressure bifurcated pipe and water inlet tunnel, thirdly, the reason why local rockburst took place was that stress concentration came into being near tunnel heading for stress in wall rock readjusted during tunnel excavation.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2004年第10期1672-1676,共5页
Rock and Soil Mechanics
关键词
水压致裂
地应力
衬砌
岩爆
Kydraulic fracturing
crust stress
lining
rockburst
