基于岩心定向和OTV/ATV技术的露天边坡岩体稳定性研究

Stability study of open-pit slope rock mass based on oriented core and OTV/ATV survey

摘要:

某露天矿边坡岩体稳定性主要受区内断层和节理裂隙等地质结构影响，为查明岩体结构面分布特征，通过对4个岩土工程勘察钻孔进行Reflex ACT Ⅲ岩心定向处理，但由于花岗岩侵入体与沉积岩接触带附近的岩体破碎、裂隙发育影响了岩心定向准确率，各钻孔高置信度的岩心定向数据比例仅为8.05%~34.29%。为此，本文采用光学电视图像（OTV）/声学电视图像（ATV）测井技术，通过高分辨率、连续、定向的360°钻孔壁图像有效获取了岩性和构造特征、关系和方向数据，提高了钻孔岩心定向的地质结构信息数据精度。在此基础上，利用赤平极射投影理论，通过动力学分析，发现该露天边坡主要破坏模式是楔形滑动破坏，概率为12.66%~34.99%，其次为平面滑动，概率为3.40%~20.36%，为露天开采边坡控制提供了依据。

Abstract:

The stability of the slope of an open-pit mine is mainly affected by geological structures such as faults and joint of rock mass. In order to identify the distribution characteristics of the rock mass structural， the Reflex ACT Ⅲ tools were used to unify thecore orientation of 4 geotechnical survey holes. However， the proportion of highly reliable core orientation data for each borehole only 8.05%~34.29%， due to therock mass fragmentation and joint development near the contact zone between granite intrusions and sedimentary rocks， which affects the accuracy of core orientation. Therefore， this article took OTV/ATV survey to obtain lithology and structural characteristics， relationships and direction data effectively and improve the accuracy of geological structure information data of core orientation， through high-resolution， continuous and oriented 360° borehole wall images. Based on this， failure mode of the open pit mine was studied by equatorial polar projection theory and dynamic analysis. According to the result， the main failure mode is wedge sliding failure， with a probability of 12.66%~34.99%， followed by plane sliding， with a probability of 3.40%~20.36%， which provides the foundation for open-pit mining slope control.