基于水平钻探的地形变观测平硐勘察方法研究

Research on investigation method of terrain change observation adits based on horizontal drilling

摘要:

地质结构复杂的山区隧道勘察，常用垂直钻孔，难以满足地形变观测平硐勘察要求。论文以西昌某地壳地形变观测平硐工程勘察为例，提出一种基于水平钻探技术解决隧道勘察的中精细围岩分级和涌水量估算两大关键问题的方法。通过对水平钻探全孔岩心节理裂隙进行详细编录，统计节理裂隙线密度，再结合场区节理裂隙发育优势方位及间距，建立本工程场区岩体标准模型，对标准模型的统计分析最终得到一维岩心裂隙线密度与三维岩体体积节理数J_v的换算系数K，再根据规范计算得到隧道围岩的岩体完整性系数K_v及BQ值，精细划分隧道围岩类别。水平钻探在钻进过程中能准确判断隧道涌水位置并测量涌水量，为隧道涌水量计算提供准确的计算参数。

Abstract:

Vertical drilling technology is commonly used in mountain tunnel investigation with complex geological structure， however， it is difficult to meet the requirements of the terrain change observation adits investigation. Taking an terrain change observation adit investigation project in Xichang as an example， a method to solve the two key problems of detailed surrounding rock classification and water inflow estimation in tunel investigation based on horizontal drilling technology is put forward. Detailed logging of the joint fissures in full-hole horizontal drilling cores and the joint fracture linear density statistics are collected. Combined with the developed orientation and space of the joint fractures in the project site area， the standard rock mass model is established. Through statistical analysis of the standard model， the conversion factor K of the one-dimensional core fracture linear density and the three-dimensional volume joint number J_v of the rock mass is finally obtained. After that， the rock mass integrity index K_v and BQ values of the tunnel surrounding rock are calculated according to the standards and specifications， and then the classification of tunnel surrounding rock can be more detailed divided. In the process of drilling， horizontal drilling can be used to accurately judge the location of tunnel water inflow and measure it， which provides accurate calculation parameters for the calculation of tunnel water inflow.