原位岩土CT及其关键技术探讨

当前应用工业X射线CT技术观测岩土内部微观结构和力学特性成为研究工程地质的热点课题。然而,现有CT技术的“笨、大、重、险、贵”限制了现场应用能力,且常规岩土工程勘察方法存在丢失或破坏原有地质信息的问题。本文提出原位CT技术的概念,并指出其在岩土工程勘察领域应用中的关键技术。基于超小型冷阴极脉冲式X射线管及成像设备搭建随钻原位CT实验平台,实验结果表明该方法能够实现原位岩心数字采样与CT快速重构。在此基础上明确后续研究重点和关键技术,主要包括2D/3D CT快速重构新理论和新方法,解析CT重构图像与岩土颗粒特性之间的关系以及局部精细结构重建算法,构建精确的原位岩心3D微观结构模型;结合3D打印技术制备原位置岩土准样本,研究等效准样本的力学特性;建立时-空四维岩土工程勘察数据库,引入人工智能算法形成具有学习和预测的反馈评价体系,对丰富当前岩土工程勘察方法和完善原位CT技术具有重要的科学意义。 

In-situ Geotechnical CT and Its Key Technologies

The current application of industrial X-ray CT technology to observe the internal microstructure and mechanical properties of geotechnical soil has become a hot topic in engineering geology. However, the "large, heavy, dangerous, expensive" of the existing CT technology limits the field application capability, and the conventional geotechnical engineering survey method has the problem of losing or destroying the original geological information. This paper proposes the concept of in-situ CT technology and points out its key technologies in the application of geotechnical engineering. Based on the ultra-small cold cathode pulsed X-ray tube and imaging equipment, the in-situ CT experimental platform was built. The experimental results show that the method can realize in-situ digital sampling and CT rapid reconstruction. On this basis, the key points and key technologies of the follow-up research are clearly defined, including the new theory and new method of 2D/3D CT rapid reconstruction, and the analysis of the relationship between CT reconstructed image and geotechnical particle characteristics, and the local fine structure reconstruction algorithm, and the development of in-situ core 3D microstructure model. 3D printing technology will be combined to prepare the original position rock soil quasi-samples used to study the mechanical properties. A time-space four-dimensional geotechnical engineering measurement database will be established, and artificial intelligence algorithms were introduced to form a feedback evaluation system with learning and prediction. It is of great scientific significance to enrich existing geotechnical engineering survey methods and improve in-situ CT technology.