Journal of
Geology and Mining Research

  • Abbreviation: J. Geol. Min. Res.
  • Language: English
  • ISSN: 2006-9766
  • DOI: 10.5897/JGMR
  • Start Year: 2009
  • Published Articles: 169

Article in Press

Comparative Application of Photogrammetry, Handmapping and Android Smartphone for Geotechnical Mapping and Slope Stability Analysis

Jabulani Matsimbe

  •  Received: 11 May 2020
  •  Accepted: 24 July 2020
With increasing awareness of geotechnical risks in civil and mining structures, taking advantage of smartphones technology to study rocky slopes can play a key role in the development of safe and economical structures for human welfare. In Malawi, there is a research gap on applications of portable devices to collect geotechnical data. Geologists and engineers still use the unsafe tedious handmapping technique to collect geotechnical data. A road cut that experiences frequent rockfall is used as a case study to investigate if there is a role for smartphones in geotechnical mapping and slope stability analysis by comparing mean plane orientations, and set statistics of data clusters collected through photogrammetry, android-smartphone and clar compass clinometer. Smartphone’ data capture speed is faster than clar inclinometer. Stereographic and kinematic analysis shows that the 75° dipping road cut is predominantly prone to wedge failure with minor planar failure. For slope stability, Q-slope suggests a new slope angle of 60° to 66°. An acceptable tolerance limit or error between handmapping and remote data capture systems should be less than +/- 15°. Set analysis on 111 comparable data points gave a maximum pole vector difference of 10.5°, with the minimum having a difference of 4.8°. For dip, the standard deviations vary from 4.9⁰ to 9.5⁰ while their means vary from -2⁰ to 2.75⁰. For dip directions, the standard deviations vary from 3.2⁰ to 4.3⁰ while their means vary from -6⁰ to 0.75⁰. Based on the research findings, android smartphones have a role in geotechnical mapping and slope stability analysis due to their allowable orientation errors which show less variance in measured dip/dip directions among the three methods. This new knowledge will assist students, contractors, mining companies and roads authorities in Malawi in carrying out geotechnical assessments due to the lower cost of a smartphone as compared to a Clar compass, Total Station and LIDAR.

Keywords: Discontinuities, Excavation, Geology, Malawi, Reliability.