Three-dimensional stress testing device for single-hole multi-point fiber grating hollow inclusions in rock mass engineering

Abstract

The invention relates to a three-dimensional stress test device for a single-hole multi-point hollow fiber grating inclusion in rock mass engineering. The three-dimensional stress test device is mainly composed of two or more unit fiber grating cylindrical hollow inclusion stress gauges, rigid connection rods, centering supports, a wavelength demodulator and a computer. The unit fiber grating cylindrical hollow inclusion stress gauges are composed of epoxy resin hollow inclusion bodies, rigid connection end rings, fibers and gratings. The fibers are fixed into axial grooves, radial grooves and spiral grooves in the outer surfaces of the stress gauges in a wound mode. The test device is installed to a drill hole in a rock mass and coupled with the part, located on a drill hole wall, of the rock mass through slip casting fluid, so that testing of three-dimensional disturbance stress distribution and testing of the time-space evolution law of three-dimensional disturbance stress distribution in the rock mass engineering are achieved. As the fiber grating technology and the hollow inclusion technology are coupled, the test device is resistant to corrosion, groundwater interference and electromagnetic interference and high in test accuracy, has high adaptability to complicated geological and hydrological conditions in the rock mass engineering and can be widely applied to three-dimensional disturbance stress tests for underground tunnels and slope rock masses in water conservancy and hydropower engineering, mine engineering, traffic engineering and the like.

Description

technical field [0001] The invention relates to a three-dimensional stress testing device for single-hole multi-point fiber grating hollow inclusions in rock mass engineering. The device can be widely used in the excavation and operation of underground tunnels and slope rock masses in water conservancy and hydropower, mining, transportation and other projects. Three-dimensional disturbance stress test. Background technique [0002] The geological environment and stress conditions existing in rock engineering are complex. Landslides, landslides and rockbursts that occur during large-scale engineering construction are the most critical factors that affect the safety and operation of engineering construction. Engineering accidents often cause damage to construction equipment and major casualty accident. The occurrence of these disasters is firstly reflected in the change of stress in the rock mass. Through the direct acquisition and analysis of stress evolution information on ...

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Problems solved by technology

After comprehensive analysis and comparison, the disadvantages of the above-mentioned disclosed invention patents are: first, the unidirectional drilling stress gauge can only test the rock mass stress change in a single direction, while the above-mentioned three-directional solid matrix and the Australian CSIRO hollow inclusion stress gauge can only test It can test the three-dimensional stress of the bottom of the hole or a single measuring point in the hole, but it has not been able to test the multi-point stress of the entire length of the drilled hole in the rock mass; and poor anti-interference ability, it is not suitable for long-term monitoring under complex and harsh conditions such as water, acid-base corrosion, rock mass cracks, etc. It is completed by multiple fiber gratings. Since the base body is a solid cube or cylinder, high-strength metal materials or concrete make the sensor less sensitive to rock strain response, and the strain gauge is installed on a given plane of the cube. The test method is only suitable for testing in weak rock mass, and cannot truly and accurately reflect the three-dimensional stress state and direction of confining pressure on hard rock mass in space

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