A device and method for measuring ground stress through a single borehole

Abstract

The invention provides a device and a measurement method for measuring ground stress through a single borehole. The invention can obtain accurate magnitude and direction information of the ground stress at a measuring point by constructing a single borehole. The device includes a core positioning and photographing device in a hole and a core ground reorientation device. The method is to first use the in-hole directional camera device to position and take pictures of the unbroken core in the stress zone of the original rock in the borehole, and obtain a clear image of the section feature points of the core in situ, and then use the core ground reorientation device on the ground Accurate simulation reproduces the spatial position of the borehole including parameters such as azimuth and inclination, and then restores the real spatial position of the core when it is in situ underground through graphic feature point comparison, and draws the azimuth marking line, and then presses the mark Acoustic emission small specimens are processed and manufactured in the direction of the line, and finally the corresponding Kaiser effect points are obtained by carrying out acoustic emission signal tests on rock specimens in all directions, and the real three-dimensional stress value of the underground rock mass is calculated.

Description

technical field [0001] The invention belongs to the technical field of ground stress testing in underground rock mass engineering, and in particular relates to a device and a measuring method for measuring ground stress through a single borehole. Background technique [0002] In-situ stress refers to the internal stress of the rock mass in the earth's crust in its natural state. It is the fundamental force that causes deformation and destruction of mining, water conservancy and hydropower, civil construction, roads and various underground geotechnical excavation projects. A scientific and accurate grasp of its distribution in the crust is a necessary prerequisite for determining the mechanical properties of engineering rock mass, analyzing the stability of surrounding rock, and realizing scientific decision-making, design, and excavation of geotechnical engineering. The natural in-situ stress field existing in the rock mass can only be obtained by means of actual testing at...

AI Technical Summary

Problems solved by technology

At present, both at home and abroad are trying to push the geostress measurement technology of AE method to a deeper and wider practical stage, but the problem of core orientation has not been solved well, that is, if the traditional AE method wants to obtain the real three-dimensional geostress information of underground rock mass (including size and direction), it is necessary to use multiple oriented cores with a certain angle at the measuring point as the test material (usually a vertical drill hole and three horizontal drill holes with an included angle of 45°), so it takes a lot of energy Use special directional coring tools to drill downhole or rock formations to drill directional cores. The high cost, low efficiency, and time-consuming process of directional cores makes this method unable to be effectively promoted.

However, the paleomagnetic orientation method, in-hole television and rock formation scanning orientation method developed in recent years cannot be effectively promoted due to the engineering applicability in actual use.

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