岩石内应力的X射线-中子散射测量方法

岩石内应力的储存和释放对深地资源和能源开发具有重要约束。矿物晶格间距的动态变化是揭示岩石内应力演化的重要指示。X射线衍射法是当前获取矿物晶体结构的主要手段，可以准确测定矿物的特征衍射峰。但是，对于具有复杂结构和矿物组成的岩石，X射线在穿透过程中携带的统计信息，难以反映矿物晶格间距的细节特征。中子射线的能量高、穿透深度大，且与原子核反应，因而能更准确地刻画矿物元素位置和结构细节，但中子的波长较长、校准困难，结果具有不确定性，导致中子射线在岩石内应力研究中未能发挥应有作用。在分析X射线、中子技术优势和固有局限的基础上，提出了岩石内应力的X射线-中子衍射测量方法，重点剖析了该方法的基本原理，提出了该方法的关键技术与研究前景。得出了如下结论:利用X射线在确定岩石矿物晶格参数的优势，结合加热处理等技术，可实现岩石矿物无应力条件下晶格间距的标定; 采用中子衍射技术可精确测量岩石矿物的衍射偏移峰，实现岩石内应力深度轮廓的精准刻画; 结合X射线与中子的优势，可实现岩石内应力绝对值的精确测量。提出的技术手段有利于揭示岩石内应力的微观储存和释放过程，以及长期存留的物质条件和物理力学机制，并有望为岩石矿物组成和微观结构研究提供一种新的技术方案。

A NOVEL METHOD FOR DETERMINATION OF ROCK INNER STRESS BASED ON X-RAY AND NEUTRON SCATERRING

The dynamic change of lattice spacing of rock minerals reflects the process of inner stress storage and release in rock. X ray diffraction is a major approach to determine minerals crystal structure parameters, including lattice spacing. It is difficult to inverse detailed structure of minerals by X ray due to restrictions of information presented by X ray attenuation, which are statistically average. Fine mineral structures and element location could be obtained by neutron rays because of high-energy and thick penetration depth. The measurement of lattice spacing of rock minerals is the most pressing problem in understanding of rock inner stress storage and release. In this work, a novel method for determination of rock inner stress based on X-ray and neutron diffraction is proposed. The basic principle of the method is analyzed, and the key technology and research prospects of the method are proposed. The following conclusions are drawn: taking the advantage of X-rays in determining the lattice parameters of rock minerals, we can achieve the dating of the lattice spacing of rock minerals combined with heat treatment technology. The diffraction deviation peaks of rock minerals then can be accurately measured by neutron diffraction technology, aiming at achieving the accurate depiction of the depth profile of the stress in the rock. The absolute measurement of the absolute value of the stress in the rock can be achieved by combining X-rays and neutrons. The methods proposed in this paper are helpful to reveal the microscopic storage and release process of the stress in the rock, as well as the long-term remaining material conditions and physical mechanical mechanisms, and are expected to provide a new technical solution for the study of rock mineral composition and microstructure.