ABSTRACT:

New 3D data acquisition techniques allow to obtain geometrical information of exposed rock masses. This information can be used to characterize some geo-mechanical parameters of rock slopes, allowing users to remotely obtain information. Recently, many researchers have been working on the extraction of geomechanical parameters of rock masses using 3D point clouds, such as the number of discontinuity sets and their orientations, the normal spacing and the persistence. In this contribution we use two novel open source programs:

  1. Discontinuity Set Extractor (DSE) aids to analyse 3D point clouds detecting the number of discontinuity sets, classifying each point with its discontinuity set and plane equation and calculating their normal spacing; and

  2. SMRTool calculates the geo-mechanical quality of a rock slope by means of the Slope Mass Rating (SMR) index. In order to illustrate the use of the two software programs, we analyse the geo-mechanical quality a slope placed in the National route N-332 in El Campello (Alicante, Spain), in the named Flysch sequence of Alicante, using 3D point clouds. The 3D point cloud was analysed using the previously mentioned open-access tools. Their use allowed to extract the discontinuity sets, normal spacing and persistence using a software which code can be inspected and improved without cost. Moreover, it allows to reproduce the full analysis process using the same method parameters.

1 INTRODUCTION

Rock mass classification systems are well known tools which are useful for characterizing rock mass properties, in order to assign an "index of quality" for stability purposes. These tools are used worldwide by geo-mechanical engineers in the design or pre-design stages of civil or mining projects. The quality assessment of a rock slope, through the geo-mechanical classification, is calculated using certain parameters. These parameters are usually acquired through timeconsuming field investigation techniques: geological compass for obtaining discontinuity orientations, tape measurements for discontinuity spacings or persistence and roughness analysis by local examinations. Sometimes, fieldwork campaigns can be affected by several restrictions, being well known examples, such as, safety issues in active rockfall areas, possible access limitations and intensive work requirements in highly fractured rock masses. More recently, several attempts have been made to determine the rock mass quality using remote sensing data or digital pictures.

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