Development and testing analysis of in-situ stress measurement technology based on borehole deformation method
LI Shaojun1，ZHENG Minzong1，2，QU Dingjun3，KUANG Zhihao1，2，WANG Guojun3，QIU Shili1
(1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. University of Chinese Academy of Science，Beijing 100049，China；3. Hubei Yihua Group Mining Co.，Ltd.，Yichang，Hubei 443000，China)
Abstract：With the development of electronic technology，various in-situ stress testing equipment is gradually developing towards wireless measurement. This paper develops a digital integrated system that can automatically measure and collect data，a wireless in-situ stress measuring deformeter based on the principle of aperture deformation method is designed，and the composition，testing principle，measurement method and calibration verification is introduced in detail. In order to demonstrate the reliability of this probe，all four steel ring strain sensors are calibrated by using Carlson deformation gauge calibration station，and the relation between the voltage signal and the deformation of the steel ring is obtained. The results show that there is a good linear repetition relationship between the voltage change of the steel ring and the deformation of the steel ring. The resolution of a single steel ring can reach 0.025 ，and the measurement accuracy is improved by about 3 times. The overall calibration test of the probe with aluminum cube and granite cube show that the measurement error of the deformeter is less than 5% and the absolute error is less than 0.6 MPa，indicating that the measurement result of the probe is accurate and can meet the requirements of field use. The wireless design of in-situ stress measuring deformeter facilitates the measurement of in-situ stress in deep holes，and can realize the continuous reading of the measured data in the whole process of over-coring，thus avoiding the precision shortage of limited discrete data obtained by manual measurement and reading.
2021, Vol. 40 
