基于孔内电视技术的岩体节理裂隙特征研究

Characteristics of Rock Joints and Fissures Based on Borehole Television Technology

岩体节理裂隙的分析是工程地质评价岩体特征的重要依据,全景式孔内电视技术可以清晰、直观地观测孔内岩体的节理裂隙发育特征。在全景式孔内电视测孔图像的基础上,通过对海南某核电项目2个钻孔岩体孔内电视成像节理裂隙的解译、统计等定量分析,判断了岩体主要节理走向与倾角范围,分析了优势节理;并对岩体节理裂隙的倾角、节理线密度进行了统计分析;在此基础上运用岩体质量IRMI指标对测试孔的岩体完整性进行了评价,并与RQD值、声波测试结果进行对比,分析了全景式孔内电视技术的使用限制因素。结果表明:孔内电视的岩体质量指标IRMI值高于钻探RQD值,岩体的质量程度优于RQD值的判断结果;孔内电视可以直观清晰地观察岩体的节理裂隙构造位置、产状、充填物情况,并能区分岩体的机械破碎与节理裂隙破碎,在一定程度上弥补了钻探技术因取芯不足而导致对岩体节理裂隙描述不清的问题;结合IRMI指标、RQD值、声波测试结果对岩体质量的评价更为准确。

The analysis of rock joints and fissures is an important basis for engineering geological evaluation of rock mass char-acteristics.Panoramic borehole television technology can clearly and intuitively observe the development characteristics of rock joints and fissures in the borehole.based on the panoramic borehole television image,through the interpretation,statistics and other quantitat-ive analysis of the joints and fissures in two boreholes of a nuclear power project in Hainan,the strike and dip range of the main joints in the rock mass are determined,and the dominant joints are analyzed;the dip angle and linear density of the joints and fissures in the rock mass are statistically analyzed.On this basis,IRMI index of rock mass quality is used to evaluate the rock integrity of the test holes,and the RQD value and acoustic test results are compared.The limitations of panoramic borehole television technology is ana-lyzed.The results show that:the IRMI value of rock mass quality index of borehole television is higher than that of drilling RQD,and the quality degree of rock mass is better than RQD;the structural position,occurrence and filling material of rock mass can be ob-served directly and clearly through borehole television,and the mechanical fracture and joint fracture of rock mass can be distin-guished,which can make up for the lack of core drilling technology to a certain extent.It is more accurate to evaluate the quality of rock mass by combining IRMI index,RQD value and acoustic test results.