Deep-hole in situ stress measurement method in high-altitude area based on remote sensing technology

Abstract

In order to improve the understanding of the physical properties of earthquakes and the interior of the earth, a method for measuring deep-hole in situ stress in high-altitude areas based on remote sensing technology is proposed. The area of 2500 m above sea level is selected as the research area of in situ stress measurement in this paper. The digital image of Landsat TM5 (30 m) is used as the main information source, and the spectrum of the visible-shortwave infrared band is 0.38–2.5 um. The information enhancement of TM7-4-2 band is selected to process the clear remote sensing image of the research area. After locating deep boreholes based on remote sensing images, the in situ stress of deep boreholes is measured by the non-elastic strain recovery method. Core samples at five depths of 730 m, 980 m, 1030 m, 1080 m, and 1110 m are extracted and pasted with 18 strain gauges. The principal stress direction is obtained by core orientation, and the stress components are determined by calculating six independent directions of inelastic normal strain and rock’s inelastic strain recovery flexibility. The results are as follows: the direction of maximum horizontal principal stress is 31°~46° and the dominant direction is 36°; the inelastic strain of each strain gauge is positive strain, the curve increases steadily with time, and the initial inelastic strain increases quickly and then slows down, which accords with the law of inelastic strain change. Experiments show that this method can provide a basis for the study of geological conditions at high altitudes.