In-situ digital three-dimensional borehole wall strain gauge based on complete temperature compensation technology

Abstract

The invention provides an in-situ digital three-dimensional borehole wall strain gauge based on a complete temperature compensation technology, which belongs to the field of rock mass stress measurement and monitoring. The strain gauge comprises an injection-type hollow inclusion strain gauge skeleton, a high-precision self-compensation strain sensor, a double-earth wire and complete temperature compensation measurement circuit, and a local digital acquisition integrated circuit board, wherein the strain gauge adopts an injection-type design to realize mounting; the self-compensation high-precision strain sensor and the complete temperature compensation circuit eliminate temperature influences in long-term monitoring; the double-earth wire circuit compensates a digital circuit leveling range; and the instantaneous acquisition technology of the digital circuit board eliminates resistor heating influences, thereby realizing long-term effectiveness and relevance of monitored data. The strain gauge has two acquisition modes of a manual power-off continuous acquisition mode and an automatic continuous acquisition mode, short-term and long-term monitoring on the three-dimensional strain of the borehole wall through one-time mounting can be realized, and as multiple wireless connection modes and wireless charging interfaces are preserved, real-time transmission of data from a measurement point to a control room can be realized.

Description

technical field [0001] The invention relates to the field of rock mass stress measurement and monitoring, in particular to an in-situ digital three-dimensional hole wall strain gauge based on complete temperature compensation technology. Background technique [0002] In-situ stress is the natural stress existing in rock mass, and it is the most important factor that determines the excavation, design, and stability analysis of underground engineering. The hollow inclusion strain gauge method for ground stress measurement is a three-dimensional ground stress measurement method recommended by the International Society of Rock Mechanics, and is currently the only ground stress measurement method that can obtain the magnitude and direction of the underground three-dimensional principal stress at one time. [0003] However, most of the current methods of measuring ground stress with hollow inclusion strain gauges use long wires to lead out the measurement signals, and the resistan...

AI Technical Summary

Problems solved by technology

The borehole stress gauge used in mining has the advantages of simple installation and easy operation, but it is developed from the application of coal mining and uses oil pressure monitoring, which cannot achieve long-term measurement, and the measured data is the internal pressure value of the jack, not the rock mass Internal stress value; the local digital hollow cladding strain gauge in Australia can theoretically monitor the disturbance stress, but it adopts the traditional bridge acquisition method and must ensure stable power supply throughout the monitoring process; Bai Jinpeng, Peng Hua, etc. The developed non-exportable probe has a standby time of 3 months and a working time of 20 hours, and the temperature changes in the long-term monitoring are larger. The compensation plate method of the traditional probe structure cannot fully compensate for the influence of temperature, and the accuracy is poor.

Therefore, the above two kinds of hollow inclusion equipment cannot carry out long-term stress monitoring in the complex environment of underground space

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