Engineering Geological Behaviour of Heterogeneous and Chaotic Rock Masses

Abstract

The engineering characterization of heterogeneous and complex geological formations for estimating their rock mass strength and deformability characteristics constitutes a challenge to geo-scientists and engineers dealing with the design and construction of slopes and tunnels. Mélanges and similar heterogeneous mixtures of hard blocks in weaker matrix, known as "bimrocks", present an overall strength significantly greater than the matrix strength, because the presence of rock blocks, above a threshold volumetric proportion, influences the mechanical characteristics and the behaviour of these rock masses. Moreover, recent studies have shown that the strength and mechanical behaviour of heterogeneous and composite rock masses such as flysch and molasses consisting of alternating layers of competent and incompetent rocks are governed by the presence and volumetric percentage of the interlayers of the weaker rocks.

Preliminary Characterisation of an Italian Soft Rock with a Block-in-Matrix Fabric

“…), it could be much lower than this value. Previous findings from the literature [25,30,41,45,48,58,59] have indeed shown that C varied from 5 up to 24 for chalks, from about 7 to 21 for sandstones and from 13 to 15 for argillaceous rocks. Hence, a conversion factor equal to 14 was considered reliable and used for the mélange under study.…”

Engineering geological behaviour of volcanic formations. References to instability phenomena and town planning in Lesvos Island, Greece

“…When the volcanic formations are highly to totally weathered, usually clay rich soil formations are evident and slope instabilities in the form of rotational failures exist. Since weathered volcanic rocks and tuffs can produce block-in-matrix formations the block proportion in the soil mass can influence the geometry of the failure surface as it may be impeded by blocks (Medley and Sanz Rehermann, 2004;Tsiambaos, 2010).…”

Konglomeralarda malzeme ve kütle özelliklerinin belirlenmesi ve kaya taşıma gücü kapasitesi açısından değerlendirilmesi

“…Araştırmacılar tünel güzergahı boyunca gözlenmiş olan konglomera birimlerini "zayıf dayanımlı kaya" olarak tanımlamışlar ve tünel çalışmasında stabilite problemleri meydana getirebileceğini bildirmişlerdir. Tsiambaos [10], düşük dayanımlı bir matriks içerisinde yer alan sert tanelerin oluşturduğu bimrock (hamurda kaya) adıyla tanımlanan konglomeratik çökellerin mühendislik jeolojisi özelliklerini ortaya koymuştur. Khanlari vd.…”