嵌岩桩基岩溶洞钻探数据概率分析与应用

为探索岩溶区嵌岩桩钻探勘察的方案优化以及钻探数据的合理使用,笔者创造性地提出了背景概率、技术概率和发现概率的概念及其相互关系,建立了一桩一孔和一桩两孔钻探的情况下溶洞技术概率的物理模型,推导了相应的计算方程。通过计算发现,溶洞的技术概率与洞径大小之间存在近似双曲线的关系;一桩两孔时溶洞的技术概率相对于一桩一孔的增加倍数随洞径增大而减小,但大溶洞的漏探概率显著降低;同时,两钻孔相对距离增大有利于大型溶洞的发现。基于研究提出在勘察得到溶洞的发现概率后,还应通过技术概率分析得到场地的背景概率,进而为设计和建设方决策提供准确可靠的依据。

Probability Analysis and Application of Drilling Data of Karst Cave in Bedrock of Socketed Piles

To optimize rock-socketed piles’ drilling exploration scheme in karst area and rational use of drilling data, this paper puts forward the background probability, technical probability and detected probability, and discusses the relationship between them. Established are the physical models of technical probability of cave under the condition of one drilling hole per pile and two drilling holes per pile. Correspondingly, the calculation equations are deduced. According to the calculation, the relationship between the technical probability of karst cave and the diameter size of the cave is approximate in form of hyperbola; Compared with the technical probability under one drilling hole per pile, that of the two drilling hole per pile increases with the increasing hole diameter, but leakage probability of big cave reduced significantly; meanwhile, an increase in relative distance between two holes may indicate the existence of big cave. Therefore, when the detected probability is investigated the technical probability should also be analyzed to get the background probability of the field, for providing accurate and reliable data for project design and the decision-making..