Prediction of subsidence due to underground mining by artificial neural networks

Alternatively to empirical prediction methods, methods based on influential functions and on mechanical model, artificial neural networks (ANNs) can be used for the surface subsidence prediction. In our case, the multi-layer feed-forward neural network was used. The training and testing of neural network is based on the available data. Input variables represent extraction parameters and coordinates of the points of interest, while the output variable represents surface subsidence data. After the neural network has been successfully trained, its performance is tested on a separate testing set. Finally, the surface subsidence trough above the projected excavation is predicted by the trained neural network. The applicability of ANN for the prediction of surface subsidence was verified in different subsidence models and proved on actual excavated levels and in levelled data on surface profile points in the Velenje Coal Mine. (C) 2003 Elsevier Science Ltd. All rights reserved

Deformation analysis: The Fredericton approach

In this article, the Fredericton approach to deformation \ud analysis is presented. It is possible to use several \ud deformation models to determine the differences \ud between the geodetic observations or between the \ud coordinates of points in geodetic network in more \ud epochs. The most appropriate deformation model has \ud been chosen based on statistical testing and available \ud information about dynamics at the area of interest. \ud First, a theoretical background of the approach \ud is described. Then it is applied to the generated \ud observations in two epochs. In the present example, the \ud results of the Fredericton approach differ only slightly \ud from the results obtained with the Delft, Karlsruhe in \ud Hannover approache

GPS-derived geoid using artificial neural network and least squares collocation

The geoidal undulations are needed for determining the orthometric heights from the Global Positioning System GPS-derived ellipsoidal heights. There ore several methods for geoidal undulation determination. The paper presents a method employing the Artificial Neural Network (ANN) approximation together with the Least Squares Collocation (LSC). The surface obtained by the ANN approximation is used as a trend surface in the least squares collocation. In numerical examples four surfaces were compared: the global geopotential model (EGM96), the European gravimetric quasigeoid 1997 (EGG97), the surface approximated with minimum curvature splines in tension algorithm and the ANN surface approximation. The effectiveness of the ANN surface approximation depends on the number of control points. If the number of well-distributed control points is sufficiently large, the results are better than those obtained by the minimum curvature algorithm and comparable to those obtained by the EGG97 model

Determination of the nonverticality of high chimneys

This article deals with practical examples of the applications of modern tachymeters in the determination of the nonverticality of high industrial chimneys, as an alternative to the classic methods. The possibility of a reflectorless measuring mode to determine the point cloud at the chimney's circumference is described. Using these points, we are able to model the chimney as a mathematically correct body using the least squares adjustment method. Subsequently, the unknown nonverticality of the chimney is determined as the deviation of the primary axis of the modelled body from the vertical

Mine surveillance measurements during the building of NOP II shaft

The Velenje Coal Mine is building a new shaft NOP II for the \ud transportation of coal from the mine. The entrance of the shaft, \ud which is determined on the surface, and the bottom of the \ud shaft, which is expected in the point determined at the bottom \ud of the shaft, must be within the same vertical and horizontal \ud coordinate system. The starting points for the measurements \ud are the points determined on the surface, which are stable \ud or have a determined direction and velocity. The transfer of \ud the coordinate system from the surface into the shaft can be \ud carried out with the measurements using various methods. \ud The results of the measurements and the calculations are the \ud coordinate points in the shaft that are in the same coordinate \ud system as those on the surface. They are very suitable for the \ud determination of the designed NOP II shaft. At the beginning \ud of this task, we planned to determine the coordinates of the \ud starting points with a maximum precision. Based on the \ud results of an analysis, we can conclude that we performed \ud each phase of the work very well and achieved the tasks set

Deformation analysis: the DELFT approach

The Delft approach, a method for the deformation\ud analysis, is presented in this article. Based on\ud geodetic measurements, the statistical significance\ud of displacements at the surface is determined with\ud statistical methods. A numerical example shows the\ud effectiveness of the presented method

Applicability of selected methods of deformation analysis according to practical examples geodetic networks

The basic problem in deformation analysis is detection\ud and determination of stability or displacement of the\ud points in the geodetic network during two epochs. The\ud applicability of the methods of deformation analysis\ud (Hannover, Karlsruhe) and of the simple procedure\ud for testing point displacement was tested on practical\ud examples of geodetic networks for displacement and\ud deformation detection. The procedure, results and\ud assessments of the testing are described

Use of Automatic Target Recognition System for the Displacement Measurements in a Small Diameter Tunnel Ahead of the Face of the Motorway Tunnel During Excavation

During construction of the Sentvid tunnel a unique opportunity arose to measure the 3D displacements ahead of the motorway tunnel excavation face, since the exploratory tunnel was already constructed in the axis of the main tunnel. According to reviewed literature such measurements had not been performed yet and several problems regarding equipment and complete scheme of the experiment needed to be overcome. The paper gives a brief description of the Sentvid tunnel project, presents significant factors that affected the choice of the geodetic equipment and describes the scheme of the experiment. A special attention is focused on the problems relating to the operation of the instrument in demanding environmental conditions (water, dust)

Determination of point displacements in the geodetic network

This paper describes the procedure for testing the statistical significance of point displacements in the geodetic network as the intermediate stage between the adjustment of respective epochs measurements and an in-depth deformation analysis. The cumulative distribution function of the test statistic, presenting the relation between the displacement and the displacement accuracy, is determined by simulations. On the basis of this cumulative distribution function a critical value of the test statistic for a selected significance level is determined. In the null hypothesis it is assumed that the point is stable. A comparison of the critical value to the test statistic value is made and the actual risk level for rejecting the null hypothesis is estimated. Further on, a practical example of implementing the test in a simulated network is given. The test statistic proved to be simple and applicable: The points with significant displacements were identified successfully

Determination of point displacements with deformation analysis methods

U radu su opisani postupci deformacijske analize, koji na osnovi geodetskih mjerenja i uz pomoć statističkih metoda određuju prostorne pomake promatranog objekta. Za testiranje je uzeta simulirana geodetska mreža i na njoj su primijenjeni hannoverski, Ašaninov i Mihailovićev postupak. Prikazani su rezultati primijenjenih postupaka deformacijske analize i usporedbe uspješnosti određivanja stabilnih točaka.This paper aims at presenting the implementation of different deformation analysis approaches for determining – on the basis of geodetic observations and with the use of statistical methods – the three-dimensional displacements of a given object. On the test example of a simulated network the analysis of the Hannover, Ašanin and Mihailović approaches has been carried out. Additionally, a comparison regarding the efficiency of stable point identification according to the deformation analysis approaches has been made