Study on quantitative characterization method of measurement accuracy of geostress technology and equipment

Abstract

In view of the shortcomings of existing research, the definition, quantitative characterization of all elements and its application of geostress measurement accuracy are studied. On the basis of the summary and classification of the measurement accuracy research in past decades, the definition of geostress measurement and its accuracy are given from the perspective of closed-loop measurement, different from the definition of taking rock mass as measurement object. The function and significance of the measurement accuracy research is also clearly pointed out. The quantitative characterization idea and procedure of geostress measurement accuracy are introduced. A physical model test device is provided, and the coordinate setting and the method of reducing the uncertainty of measurement accuracy representation by coordinate conversion are explained. 2D and 3D accuracy characterization formulas of all stress component which including single indexes of average-mode and maximum-mode are given first in the world, and the calculation method of angle error is discussed, the relationship between characterization modes and technical requirements is explained. Taking the measurement accuracy characterization of the physical model test results of early USBM borehole deformation gauge(USBM-type gauge) and CSIRO hollow inclusion strain cells(CSIRO HI cells) as example, the quantitative characterization process of measurement accuracy is shown, the characterization indexes are compared with the original ones, and the overall measurement error of the single index of the maximum-mode of the two test technology is 10% and 27%, respectively.Accuracy indexes of different dimension test methods are calculated and compared for the first time, and the data show that the overall measurement accuracy of the former is much better than the latter.