Research on improving displacement measurement precision in physical simulation of water-preserved mining

Considering the wide-range and nonlinear characteristics of strata movement and the demand between large range and high precision in the physical simulation of water-preserved mining,a method for improving displace- ment measurement precision in physical modeling has been proved by experiments. The results show that the meas- urement accuracy is improved as the number of reference points and displacements increase. The increase of the number of reference points could reduce the system error which fluctuates in a range depending on the number of ref- erence points and the fluctuation ascribes to the plus or minus of error. The mean error starts to reduce and diminish significantly when the number of reference points is 15 and 25 respectively. Therefore,at least 25 reference points are required to ensure the required precision. The method suggests a way for measuring strata movement in mining physical models.