基于X射线衍射法的含石英脉硅质板岩封闭应力测量

MEASUREMENT OF LOCKED-IN STRESS IN QUARTZ VEIN SILICEOUS SLATE BASED ON X-Ray Diffraction

岩石在冷却和漫长的地质演化过程中会有应力被封闭其中,岩石中存在封闭应力的现象逐渐被人们所认识。为揭示岩石封闭应力的存在形式,利用X射线衍射仪,对含石英脉硅质板岩样品采用侧倾固ψ法测量并计算了封闭应力的量值,确定了封闭应力的主应力。研究发现:含石英脉板岩样品测试石英脉区域石英粒径约40μm;在衍射角152°~156°扫描范围具有良好的独立衍射峰,获得的不同ψ时的(324)晶面衍射图谱,其衍射峰偏移方向具有一致性,证明了封闭应力的存在;石英脉测量点的封闭应力为压应力,最大主应力平行脉体走向(22.71 MPa),最小主应力垂直脉体走向(12.97 MPa);基体测点中未测得2θ–sin^(2)ψ线性相关规律。本文所提出的封闭应力的测量方法可为后续开展不同类型岩石封闭应力的观测和相关研究提供参考。

In the process of rock cooling and long geological evolution,some stress are enclosed.The phenomenon of enclosed stress in rock is gradually recognized.In order to reveal the existence form of locked-in stress in rock,the quantity of locked-in stress is measured and calculated by the tilt solidψmethod with an X-ray diffractometer,and the principal of locked-in stress is determined.The results show that the quartz particle size is about 40μm in the target area of quartz vein slate samples.In the diffraction angle range of 152°~156°,the diffraction peak of(324)crystal plane obtained with differentψis consistent,which proves the existence of sealing stress.The sealing stress of quartz vein measurement point is compressive stress.The maximum principal stress(22.71 MPa)is parallel to the vein body strike,and the minimum principal stress(12.97 MPa)is vertical to the vein body strike.The linear correlation law of 2θ–sin^(2)ψwas not found in the matrix measurement points.The measurement method of confining stress proposed in this paper can provide reference for subsequent observations and related research of confining stress of different types of rocks.