RICERCA ITALIANA     

Analysis and mitigation of the risk induced by fast slope movements.

Università degli Studi di Parma

Abstract

The detaching of rock blocks from the mountainsides is a phenomenon commonly spread in every mountanious region of the world as well as along the rocky coastlines. The evolution of such landslide phenomena causes rock falls, rock avalanches, debris flow and other type of fast movement that are constituting a constant hazard for lives, structures and communication lines. The defense of such valuable items can be accomplished through the stabilization of the rock cliffs (using active interventions) or through the protection of human lifes and structures by means of passive interventions. The design of both type of interventions requires the knowledge of the geometrical, mechanical and hydraulical features of the rock masses forming the cliffs or the mountainsides. The first objective of this research program is to improve the methodologies and techniques for the acquisition of the rock mass discontinuities geometrical, mechanical and hydraulical features which, is known, have a major role in generating such hazardous phenomena. The aim of the research carried out by the Parma Unit, is to develop and test a procedure that will automatically select from the point cloud determined on the rock face a set of points distributed on a particular discontinuity, location, dip and dip direction using the least squares estimate of the plane interpolating the set of points. Likewise, the normal vector to the surface may be computed from an interpolation or approximation of the surface by >>>

Principal Investigator

Gianpaolo Giani Università degli Studi di PARMA

Research Objectives

The final objective of this Research Project can be defined considering the results and the objectives accomplished during the previous PRIN 2005 titled “Theoretical and experimental studies for the triggering and evolution of rockfall phenomenom” in which some of the Units partecipating to this project were also involved.
Starting from these premises it can be said that the most common fast movements (falls, rock avalanches , debris avalanches and debris flows) have been treated and considered.
The global objective of this project is therefore to better the knowledge of the phenomena that are determining the triggering and the various types of evolution of the failure of portions of rock mass detached from rock cliff or mountainside.
In particular the innovative aspects, that are also constituting the objectives of this research project are summarized in the following few pharagraphs.
Estimate of the reliability and advantages of the remote sensing survey techniques (photogrammetry and/or laser scanner) for the definition of rock mass geometry. Geometrical reconstruction of rock masses and estimate of the block volumes and of the grain size distribution of the debris deposits (Parma Unit).
Development of a methodology for the evaluation of the recurrence probability of rock fall phenomena; definition of the rock fall paths and evaluation of the rock mass motion features, in order to define the most probable invasion areas, the appropriate >>>

First Results

The results of this Research Project can be defined considering the results and the objectives accomplished during the previous PRIN 2005 titled “Theoretical and experimental studies for the triggering and evolution of rockfall phenomenom” in which some of the Units partecipating to this project were also involved.
Starting from these premises it can be said that the most common fast movements (falls, rock avalanches , debris avalanches and debris flows) have been treated and considered.
The global objective of this project is therefore to better the knowledge of the phenomena that are determining the triggering and the various types of evolution of the failure of portions of rock mass detached from rock cliff or mountainside.
In particular the innovative aspects, that are also constituting the objectives of this research project are summarized in the following few pharagraphs.
Estimate of the reliability and advantages of the remote sensing survey techniques (photogrammetry and/or laser scanner) for the definition of rock mass geometry. Geometrical reconstruction of rock masses and estimate of the block volumes and of the grain size distribution of the debris deposits (Parma Unit).
Development of a methodology for the evaluation of the recurrence probability of rock fall phenomena; definition of the rock fall paths and evaluation of the rock mass motion features, in order to define the most probable invasion areas, the appropriate >>>

Timescale

24 months

National and international background

Rock fall phenomena are common throughout all mountainous regions and along coastal cliffs, constituting a constant danger for lives, property, and human activities. Of the approximately 34,000 landslide phenomena recorded in Piemonte by the IFFI project (ARPA Piemonte, 2004), 20.9% were made up of single rock falls or areas susceptible to diffuse falls. In spite of such a wide diffusion of the phenomenon, the literature contains few examples of analyses carried out on a basin scale. In fact, the process, even though apparently traceable to a rather simple scheme of the mechanisms that govern it, is complicated by the high degree of uncertainty in the definition of the parameters that control both the triggering and the run-out phases. Furthermore, the wide extension of the areas involved (consider the maps of major transportation systems like motorways and railways) makes it difficult to collect sufficient information to conduct detailed analyses. One of the first examples of methodologies dedicated to the definition of rockfall hazard in vast areas is the STONE computer code (Guzzetti et al., 2002; Crosta & Agliardi, 2003), which is capable of evaluating the invasion area and producing thematic maps on the basis of the topographical and geomorphological information available on a basin scale and using a 3D simulation model of the trajectories of falling masses. Other similar methods have been proposed by many authors (e.g. Wieczorek et al., 1998; Jaboyedoff >>>