Horizontal effective ground stress testing method and device

Abstract

The invention provides a horizontal effective ground stress testing method. The method is established on the basis of a formula of a plane circular hole displacement elastic solution and a thick-wallcylinder, and the principle of the method is that in-situ ground stress is deduced reversely by restoring hole edge displacement deformation under the action of ground stress. The invention further provides a horizontal effective ground stress testing device. The device comprises a grouting device, a grouting pipe, a drilling sealing element, a drilled hole form and pressure measuring system, a supporting fixing frame, a connecting rod and a computer processing system. The drilled hole form and pressure measuring system comprises a multi-optical-scale phase laser range finder, a motor, a detection shaft, a three-dimensional electronic compass, a pressure sensor and a data integration chip. The computer processing system is connected with the data integration chip through a data line; a drilled hole is perpendicular to the horizontal plane, the grouting pipe is used for making the grouting device communicated with the drilled hole, the drilling form and the pressure measuring system isfixed to the supporting fixing frame through the connecting rod, the axis of the detection shaft coincides with the axis of the drilled hole, and a drilling opening is sealed through the drilling sealing element.

Description

technical field [0001] The invention belongs to the field of geostress testing, and relates to a horizontally effective stress testing method and a testing device. Background technique [0002] In-situ stress is the natural stress that exists in the formation without engineering disturbance, also known as rock mass initial stress, absolute stress or original rock stress. The state of in-situ stress is of great significance for earthquake prediction, evaluation of regional crustal stability, research on rockbursts in high in-situ stress areas, and coal and gas outbursts. According to the different test methods, the ground stress test methods can be divided into structural method, deformation method, electromagnetic method, seismic method and radiation method. According to different measurement principles, in-situ stress testing methods can be divided into stress recovery method, stress relief method, strain recovery method, strain relief method, hydraulic fracturing method, ...

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Problems solved by technology

However, the above-mentioned in-situ stress testing methods all have different limitations. For example, the hydraulic fracturing method has the inaccurate direction of the principal stress, and the interpretation of the injection pressure curve, especially the constant pressure, is sometimes very difficult.

Hollow inclusion stress relief method and casing stress relief method also have certain requirements on geological conditions and cored rocks, and further processing of the drilled borehole is required, and strain gauges are pasted in the borehole. The release method also has problems such as small holes being out of axis, and a complete core is required to pull out the core during the process of setting the core. Not only is the operation complicated, but the above problems will easily lead to a low test success rate and increase the test cost.

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