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Contents

Introduction

Humankind has utilized coal for various purposes from time immemorial and this tendency survives at the present time. Mining exerts its influence on more numerous spheres of human activity than it might appear at the first sight. In addition to the benefits of carbon usage one should bear in mind negative aspects related to its procession as well. The present master's work predominantly focuses on the deformation of the earth's surface, directly arising from coal face operations, as its primary object of study [1].

1. Theme urgency

There exist several methods for determining the duration of the ground displacement as well as the estimated daily rate of subsidence. The latter datum serves to determine both the duration and the active stage of the displacement process resulting from a single excavation depending on the average depth of mine working and the target advance rate.

The present work is aimed at determining of the correlation between the magnitude of ground deformation, time of its occurrence and its relative position within the shift trough.

2. Goal and tasks of the research

The aim of the present research is to systematize the obtained relations as well as to represent them in the IDE-compatible form when determining the protection funds for industrial facilities.

Main tasks of the research:

  1. To obtain the functional relations of the displacement dynamics.
  2. To arrange the newly obtained figures.

Research object: the ground deformation arising from coal face operations.

Research subject: establishing of the correlation between the magnitude of deformation in different parts of the trough for certain period of time.

3. The contents of research

We carried out a selection of data on profiled lines, submitted above in Microsoft Excel tables, on the basis of longterm measurements made by various monitoring stations and collected from the UkrNDMI archives. These tables show the values of subsidence and horizontal displacement per each date of instrumental record.

Example of raw data


Figure 1 - Example of raw data

All further manipulations will be made directly with the data tables.

The programme was written for selection of the required data (the array creation from the values of deformation per each date of measurement) and building charts based on them with the help of the VBA programming language inbuilt in Microsoft Excel tables. This program constitutes a beta version and provides for changes towards unification and complete automatisation of data selection. These charts represent the functional dependence of the value of deformation on time of measurement but requires differentiation on the position within the trough interior.

Diagram of the dynamics of deformation vielbein


Figure 2 – Diagram of the dynamics of deformation vielbein
(animation: 5 frames, 5 cycles of repeating 140 kilobytes),

We can easily identify the position of the test frame relatively to the origin in the shift trough interior based on the plans for the profiled lines positioning. The position of the X, Y axes remains analogous in cases of calculating displacements and deformations in any point of the shift trough [1]. The regulations [1] prescribe to identify the position of any point by splitting the lengths of the trough halves into 10 segments, which corresponds to placing 11 points equidistant from each other on the entire length of the trough half. The test frame position according to a particular line segment is characterized by the Z value that is the ratio of distance from the frame up to the origin X, Y (normal) and the length of the trough halves.

Function values Z on the profile line


Figure 3 – Function values Z on the profile line

The value of the function Δ = f (t) is defined after differentiation of the functions Δ = f (t) by Z by means of statistical methods and it most accurately describes the dependence of ground deformation for each of the 10 segments per time. Thereby we obtain the values of the functions Δ = f (t, Z).

Conclusion

Masters work is devoted to actual scientific problem of determining relationships between the amount of deformation of the earth's surface from the time of their occurrence, and relative position within the displacement trough.

The result of this research is to develop the current methodology to determine the magnitude of strain at any time, at any point located within the displacement trough

This master's work is not completed yet. Final completion: December 2011. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

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