Application of the terrestrial laser scanner in the monitoring of earth structures

Janusz P. Kogut,Elżbieta Pilecka

doi:10.1515/geo-2020-0033

Janusz P. Kogut, Elżbieta Pilecka

Open Access

https://doi.org/10.1515/geo-2020-0033

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Abstract

Abstract Terrestrial laser scanning (TLS) assists in the detection of the unsafe behaviour of slopes and scarps. It also facilitates the assessment of the stability of earthworks. Earth structures are those that are usually made of qualified ground material. One may distinguish between point structures such as mounds, forts and dams, and linear structures such as roads, railways and flood embankments. This article concerns the problem of monitoring and analysing of the effects associated with the unstable behaviour of selected earth structures. TLS enables remote sensing of surface changes in a simple and automated manner. Regular, multiple measurements with the laser scanner are applied in long-term monitoring of the behaviour of the selected objects. The discrete numerical models using, for example, the finite element method (FEM) take into account geotechnical properties of substrate and allow for the risk assessment and stability testing of such structures. The numerical model of the structure along with the parameters of the substrate are introduced into the FEM package. This allows for the analysis of stresses, strains and displacements, along with different loading cases. The work here presents a few selected earth structures for which the aforementioned analyses have been undertaken.

Highlights

The purpose of monitoring areas threatened by soil mass movements is to determine the velocity and nature of the mass movements that cause terrain deformation
The numerical capabilities associated with the increased performance of computers, their operational memory and computational capabilities yield much more efficient and effective solving and analysing such spatial 3-D cases checking the stability of the subsoil and earth structures, and the possibility of their protection against the loss of stability
Based on the performed series of analyses, it can be concluded that the numerical modelling and the surface monitoring by laser scanning technology may be successfully utilised for diagnostic evaluation of the state of earth structures

Summary

Introduction

The purpose of monitoring areas threatened by soil mass movements is to determine the velocity and nature of the mass movements that cause terrain deformation. Remote sensing methods may be divided into active and passive. The impulse is sent from the device; and after reflection from the object, it is acquired and analysed. Passive methods of remote sensing are those based on the analysis of signals emitted by the observed object. Photogrammetry is an example of passive remote sensing. It may be combined with the results of unmanned aerial vehicle surveys [9]. Discrete numerical models using the finite element method (FEM) packages that take into account the properties of substrate, allow for risk assessment and stability of earth structures. The numerical modelling of the structure along with the parameters of the substrate provides the analysis of stresses, strains and displacements for the consideration of different loading cases. Artificial intelligence methods are employed as tools for soil stability assessment [12,13]

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