摘要
施工成—兰铁路隧道段的工程勘察深孔上部为滑坡堆积的碎石土,在钻进中易发生坍塌、掉块、漏失,取心困难等情况;下部为千枚岩夹杂砂岩、石英岩,地层倾角多为70°～80°,钻进中易发生孔斜。针对上述问题,选用合理的钻孔结构,运用绳索取心工艺,采取了一系列的防塌、防斜和提高岩心采取率的措施,从而使所施工的两孔(深度分别为590m和771m)的松散层和基岩段的岩心采取率分别达到了56%和95%,终孔孔斜分别为4.5°和6.5°。
In a Chengdu-Lanzhou railway tunnel engineering investigation deep borehole,upper part is landslide deposit soil aggregate,easy to happen collapsing,spalling,leakage and coring difficulty in drilling;lower part is phyllite intercalated with greywacke,quartzite,strata dip angle is mainly 70o^80o,easy to happed hole deflection.In allusion to above problems,to use rational hole structure,wire line coring technology,and a series of measures including collapsing and deflection preventions and rock core recovery rate improvement adopted.Consequently,the two drilled boreholes（with depth of 590m and 771m） loose bed and bedrock rock core recovery rates are arrived at 56% and 95% respectively;end hole deflection 4.5o and 6.5o respectively.
出处
《中国煤炭地质》
2010年第B08期123-125,共3页
Coal Geology of China
关键词
工程勘察
钻进技术
成兰铁路
engineering investigation
drilling technology
Chengdu-Lanzhou railway
