Surface Deformation Prediction System (SDPS)

SDPS is a niche program developed through the Virginia Tech exclusively for Carlson

Calculate ground deformations (subsidence, strain, horizontal displacements, slope, etc) based on the mineplan, surface topo and geological characteristics. SDPS is a niche program developed through the Virginia Polytechnic Institute and State University (Virginia Tech) and Carlson Software is the world’s only distributor.

SDPS version 6.x constitutes the latest update of SDPS software, developed specifically for the Microsoft Windows® environment. In this respect, all programs fully utilize the central management of computer resources (i.e. memory, use of the clipboard, peripherals, etc.) provided by Microsoft Windows®. SDPS 6.x seamlessly interfaces with Carlson Software® on an AutoCad® platform, all versions of AutoCad® by Autodesk as well as Surfer® by Golder and Associates

Version 6.x of the Surface Deformation Prediction System (SDPS) is designed to provide an integrated approach to the following problems:

  • Calculation and prediction of ground deformations above undermined areas. Based on empirical or site-specific regional parameters, the operator can calculate a variety of ground deformation indices according to the profile function method as well as the influence function method. Results can be plotted using the graphing program provided, or exported to other graphing programs.
  • Calculation of pillar safety factors for room-and-pillar operations using traditional pillar stability equations, as well as calculation of pillar stability factors using the ALPS and ARMPS programs developed by the U.S. Bureau of Mines (now NIOSH).
  • In addition, the following programs also developed by NIOSH are included for completeness:
    • the Analysis of Horizontal Stress in Mining program (AHSM)
    • the Analysis of Roof Bolting Systems program (ARBS)
    • the Coal Mine Roof Rating program (CMRR)
    • the Analysis of Retreat Mining Pillar Stability – Highwall Mining program (ARMPS-HWM)
    • the Analysis of Multiple Seam Stability program (AMSS)

All NIOSH programs are included in SDPS for completeness and do not require a license to run.

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Input Parameters for Ground Deformation Calculations

In order to calculate surface deformations above an undermined area, three distinct entities must be established:

  • Location and geometry of the mined area (mine plan)
  • Location of the surface points where deformations will be calculated (prediction points)
  • Appropriate subsidence parameters developed from field observations

Ground Deformation Prediction Methods

The SDPS package includes two separate formulations for calculating ground deformations:

  • Profile function method
  • Influence function method

The profile function method of ground deformation prediction is the easiest to apply, since it requires minimum input, i.e. panel width, overburden depth, seam thickness, and percent hardrock in the overburden. The location of the prediction points is automatically established on the transverse axis of the panel, extending from the point of maximum subsidence (i.e. the panel center line) to the zero subsidence limit. The empirical parameters required are already built into the profile function equation.

For the influence function method, input requirements are more complex and generally the following steps are required for a given case study:

  • Establish the mine plan, describing the layout of the excavation, which can include more than one extraction panel (or parcel), each with a different geometry. The effect of the inflection point should be taken into account by modifying the geometry of the excavation parcel.
  • Establish the location of the prediction points, i.e. the coordinates and elevation of the surface points where prediction of deformation indices is requested. The points can be either scattered or defined by a grid.
  • Develop the empirical parameters pertaining to each case study. The average parameters established for U.S. coalfields may be used if site-specific parameters are not available. The development of site-specific parameters is recommended, however, for more representative calculations.
  • For the calculation of dynamic ground deformation indices, the time parameter should be established

The influence function module can import mineplans and prediction points directly from AutoCAD DWG files or from DXF files generated by and CAD package.

Calibration, regional adaptability

The mining parameters required for the application of subsidence prediction techniques can be obtained from mine maps, structure elevation maps, surface contour maps and borehole information. From the mine maps and from the elevation maps, the geometry of each panel and the corresponding overburden depth can be determined. From the borehole logs, the percent hardrock in the overburden can be determined. Additionally, the methods require the determination of a number of empirical subsidence parameters, which are considered site-specific. These parameters include:

  • Maximum subsidence factor for the site (Smax)
  • Distance of the inflection point from the rib (d)
  • Horizontal strain coefficient (Bs)

A number of relationships were established based on the data collected from case studies and these relationships were used for the regional application of the prediction methods. These relationships include:

  • Correlation of maximum subsidence (Smax) with the width-to-depth ratio of the panel (W/h) and the percent hardrock (%HR) in the overburden
  • Correlation of the distance of the inflection point from the rib with respect to depth (d/h) with the width-to-depth ratio of the panel (W/h)
  • Determination of the tangent of the influence angle (tanb) and the influence radius (r)
  • Determination of the horizontal strain coefficient Bs

Note that the package includes options to calibrate the influence function method for a regional application, by providing the mineplan, surface points and measured subsidence for each of the surface points.

Method Limitations

The above relationships were derived from statistical processing of all available data. Thus, during automatic calculations, a limit was imposed within the SDPS programs for both the maximum subsidence factor and the distance of the inflection point from the rib, in order to conform within the databounds used to generate the empirical parameters. In such cases, the user should use regionally developed parameters, which must be entered manually.

System Requirements

The SDPS package can be installed on any computer running Windows 7, Windows 8 or Windows 10. The minimum configuration for installing and running SDPS is the following:

  • Screen resolution 1024×768, 32 bit color and higher
  • 150 MB free disk space or more (the installation program is about 100MB)
  • Any printer supported by Windows

SDPS Pricing

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