Abstract
Slaking and weathering of weak rocks result in slope instability. Siltstones from flysch rock masses are highly susceptible to weathering, which causes rapid changes in the geotechnical properties and durability. This study investigated siltstone samples of different weathering grades from flysch rock masses from the Istria Peninsula, Croatia, and determined the effects of weathering on their engineering properties. Laboratory testing of siltstone samples of different weathering grades was conducted to determine the specific gravity, grain size distribution, Atterberg limits, and uniaxial compressive strength. The standardized slake durability index is not sufficient to classify the durability of weak rock masses such as siltstones. Therefore, the durability of siltstone samples of different weathering grades was quantified from the fragment size distribution after each of five slaking cycles. The tested samples were classified based on the disintegration ratio, and the modified disintegration ratio was used to determine potential long-term degradation of the tested samples. The results indicated that weathering has a significant influence on the plasticity, uniaxial compressive strength, and durability characteristics and thus affects the landslides and erosion processes in siltstones in the flysch zone of the Istria Peninsula.
Highlights
The study area of this investigation is the Pazin Paleogene flysch basin, which is located in the northeastern part of the Istrian Peninsula, Croatia
Laboratory tests were conducted to investigate the variability in the geotechnical parameters and the durability of the siltstone samples of different weathering grades
The values that were obtained with the Casagrande device vary between 33% for the sample of weathering grade I (FR) and 43% for weathering grade V (CW), and those from the fall cone test vary from 31% for weathering grade I (FR) to 40% for weathering grade V (CW)
Summary
The study area of this investigation is the Pazin Paleogene flysch basin, which is located in the northeastern part of the Istrian Peninsula, Croatia. It is considered to be dependent on several parameters, such as permeability, porosity, adsorption, mineralogy, microscopic texture, microfabrics, and the presence of microfractures [8,9,10,11,12,13] This makes characterizing the slaking behavior in rocks using a single parameter extremely complex [14]. The slake durability test, which was proposed by Franklin and Chandra [9], is the most widely used test for evaluating the relationship between slaking and the durability of rocks. Erguler and Shakoor [12] proposed a durability classification for clay-bearing rocks based on the disintegration ratio.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
