THE INFLUENCE OF COVARIANCE ON THE ESTIMATION OF THE ACCURACY OF VERTICAL DISPLACEMENTS, SLOPES AND DEFLECTIONS AS FUNCTIONS OF LEVELLING RESULTS IN GEOTECHNICAL MONITORING

Abstract

Research Object and Relevance. Geotechnical monitoring is an integral part of the safe operation of a facility. When the deformation network is a network of high-rise benchmarks, in addition to vertical displacements, slopes and deflections of intervals are calculated. Often, geotechnical researchers and engineers pay more attention to the quantitative values of various deformation characteristics, comparing calculated values with geomechanical models. In our article, we want to pay attention to the assessment of the quality of the calculated parameters: after all, if the geomechanical model can help in choosing the controlled deformation parameters and their critical values, the accuracy assessment allows you to choose the most effective monitoring technique and technology. Research Methods. In this article, we considered the influence of covariance moments on the assessment of the accuracy of vertical displacements, slopes and deflections depending on the equalized height values. Results. The results of the study obtained by us analytically and graphically showed that the replacement of the covariance matrix by the diagonal variance matrix does not affect the estimation of the accuracy of vertical displacements, while the RMS of the interval slopes and deflections significantly depend on the covariance. Conclusion. We draw the reader's attention to the fact that for a rigorous assessment of the accuracy of the calculated deformation values, information is needed on the total covariance matrix obtained from the results of levelling measurements adjustment in each series. We also recommend that geotechnical engineers pay attention to relative deformation networks - in order to obtain more accurate estimates of slopes and deflections, it is enough to level only the deformation network itself without using control points