A DISCUSSION ON CALIBRATION OF BOREHOLE STRAIN WATER-LEVEL ASSISTED OBSERVATIONS

This article analyzes the inconvenience and errors caused by "delay method", which is used to calibrating water level, reviews the principle and operation method of calibration instruments which are used in the new calibration method "probe-down method".Through a lot of experiments in some stations, the method reaches a perfect result with accuracy of 99%, which means that it is really worth spreading.