基于定向声波扫描的钻孔围岩结构探测方法

Detection Method of Borehole Surrounding Rock Structure Based on Directional Acoustic Scanning

在大型水利水电、能源交通等基础设施的建设中,查明岩体结构中存在的不良地质特征是保证工程顺利开展的重要基础,而常规物探方法很难探测到钻孔围岩结构的精细特征及异常区域的范围和走向。为此,在实验室岩样缺陷检测方法的基础上,提出一种基于定向声波扫描的钻孔围岩结构探测方法,该方法为了适用于钻孔围岩结构特征探测,采用定向声波探头、旋转部件及定位装置相结合的技术方法来实现。首先,根据扫描探测数据建立环形扫描矩阵,提出构建环形扫描图的数据处理方法;随后,构建声波数据和环形扫描矩阵的映射关系,将对应的声波处理数据按照映射关系进行对应匹配,形成钻孔围岩结构断面图,在叠加深度信息之后实现了钻孔围岩结构的立体图重建;最后,针对钻孔围岩缺陷区域的岩石声速及缺陷位置参数难确定的问题,利用不同频率声波在岩石中传递的相位特征关系,构建声速维和距离维2维扫描向量,采用数值分析方法求解岩石的声速及异常区域的位置,实现了钻孔围岩的结构特征立体呈现和参数提取,并将该方法应用于实际工程,验证了该方法的可行性和准确性。

In the construction of infrastructures such as the large-scale water conservancy,hydropower,energy and transportation,it is important to find out the bad geological characteristics in rock mass structure to ensure the smooth construction of the project.However,conventional geophysical prospecting methods are difficult to detect the fine characteristics of the borehole surrounding rock structure,such as the range and trend of the abnormal area.Therefore,a new method was proposed based on the laboratory rock sample defect detection method.The method based on directional acoustic scanning of detecting borehole surrounding rock structure was realized by combining directional acoustic probe,rotating parts and positioning device in order to be suitable for detecting borehole surrounding rock structure characteristics.Firstly,the annular scanning matrix was established according to the scanning detection data,and the data processing method for constructing the annular scanning map was put forward.Then,the mapping relationship between the acoustic data and the annular scanning matrix was constructed,and the corresponding acoustic processing data were matched according to the mapping relationship,thus forming the structural sectional map of the surrounding rock of the borehole.After superimposing the depth information,the structure of the surrounding rock of the borehole was realized.Finally,aiming at the difficulty of determining the parameters of rock sound velocity and defect location in the defect area of borehole surrounding rocks,two-dimensional scanning vectors of sound velocity and distance dimension were constructed by using the phase characteristics of different frequency acoustic wave transmission in rocks,and numerical analysis method was used to solve the acoustic velocity of rock and the location of abnormal area,thus realizing the structural characteristics of borehole surrounding rocks.Signature stereo rendering and parameter extraction were applied to practic-al engineering,and the feasibility and accuracy of the method were verified.