Study on Parameters Calculation Accuracy of Surface Ground Movement Improved with Helmert Variance Estimation Method

In order to improve the predicted accuracy of the sinking value with the probability integral method, the Helmert variance estimation method was applied to calculate the pre-estimated parameters of the probability integral method.The sinking value of the monitoring and measuring point could be divided to two types of ba sin central and basin boundary and the initial weighting of the two type values were determined.Then the initial value calculation of the pre-average deviation and the p arameter could be conducted.According to the correction cofficient of the pre-sinking value, the variance of the two type sinking values before the verification was esti mated.The re-weighting of the variance was applied to recalculate the parameters of the probability integral method.In combination with the information of the observati on station in a mine of Huaibei Mining Area, a parameter calculation program was written based on the Helmert variance estimation method.In comparison with the fttin g parameter calculation method of the least square method, the error in the pre-estimation of the sinking value at the monitoring and measuring point was reduced by 2 1.4% and improved the pre-accuracy.