The Use of Empirical Methods for Testing Granular Materials in Analogue Modelling.

Domenico Montanari,Andrea Agostini,Giacomo Corti,Chiara Ventisette,Marco Bonini

doi:10.3390/ma10060635

Domenico Montanari, Andrea Agostini + Show 3 more

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https://doi.org/10.3390/ma10060635

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Abstract

The behaviour of a granular material is mainly dependent on its frictional properties, angle of internal friction, and cohesion, which, together with material density, are the key factors to be considered during the scaling procedure of analogue models. The frictional properties of a granular material are usually investigated by means of technical instruments such as a Hubbert-type apparatus and ring shear testers, which allow for investigating the response of the tested material to a wide range of applied stresses. Here we explore the possibility to determine material properties by means of different empirical methods applied to mixtures of quartz and K-feldspar sand. Empirical methods exhibit the great advantage of measuring the properties of a certain analogue material under the experimental conditions, which are strongly sensitive to the handling techniques. Finally, the results obtained from the empirical methods have been compared with ring shear tests carried out on the same materials, which show a satisfactory agreement with those determined empirically.

Highlights

Analogue modelling represents one of the most useful tools to test hypotheses on the evolution and controlling factors of geological processes at different length and time scales
Laboratories do not always direct and easyand availability of all the of all the equipment needed to carry out these experiments, and above all, these devices do not equipment needed to carry out these experiments, and above all, these devices oftenoften do not allow allow the characterization of the materials at the experimental conditions, which are affected by the characterization of the materials at the experimental conditions, which are affected by particular particular handling techniques and procedures
We have explored the possibility to determine determine the material properties by means of different empirical methods applied to mixtures of the material properties by means of different empirical methods applied to mixtures of quartz- and quartz- and K-feldspar sand prepared at the experimental conditions

Summary

Introduction

Analogue modelling represents one of the most useful tools to test hypotheses on the evolution and controlling factors of geological processes at different length and time scales. The behaviour of natural rock is complex (i.e., experimentally deformed rocks are characterized by an elastic/frictional plastic behaviour with strain hardening prior to failure, and strain softening after failure; e.g., [1] and references therein), the simple Coulomb rheology may be successfully used to describe the mechanical behavior of upper brittle crust on a regional scale [2] This can be justified from the observation that rocks are affected by faults and fractures of any dimensions and orientation, coupled with mechanical heterogeneities of different origins that cause failure by reactivation to occur before the peak strength (undeformed rock strength) is reached.

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