Assessing the Behavior of Clay-Bearing Rocks Using Static and Dynamic Slaking Indices

Abstract

Clay-bearing rocks are characterized by a wide variation in engineering properties and their resistance to short term weathering due to wetting and drying phenomenon. In this study, a research study was performed on different clay-bearing rocks selected from the Ilam and the Tajarak regions (Iran) to assess suitability of the static and dynamic standard slaking tests. Also in this paper, in order to estimate durability of the clay-bearing rocks, some physicalchemical properties were used in form of multiple linear regression analyses in relation to the static and dynamic slaking indices. The test results from the static and dynamic standard slaking tests showed that the materials retained in the 2 mm mesh drum consists of disintegrated particles varying in diameter from 2 to 25.4 mm. To achieve a more realistic evaluation of the disintegration properties of rock samples after each wetting-drying cycle, a sieve analysis approach is therefore more appropriate. Comparison of the multiple linear regressions between the slaking indices and physical-chemical properties showed that the disintegration ratio could characterize the durability behavior of the rock samples in both the static and dynamic states. Also, the results indicated that the static slaking index (I s ) was more acceptable for predicting the behavior of clay-bearing rocks than the dynamic durability index (I d ).

An analysis on the slaking and disintegration extent of weak rock mass of the water tunnels for hydropower project using modified slake durability test

“…The particle size analysis enables further assessments on the extent of disintegration of the rock material after the complete slake durability test cycles when this is desired. Similar approaches of disintegration analysis have also been carried out by authors such as Erguler and Shakoor (2009), Gautam and Shakoor (2013), Heidari et al (2015), and others.…”

“…As an extension of this work, Gautam and Shakoor (2013) proposed a method in which the disintegration ratio (D R ) is calculated from particle size distribution curves of samples exposed to natural climatic conditions for a year. Heidari et al (2015) introduced a nested mesh drum apparatus with different mesh openings, enabling sieving of different grain sizes during the slake durability test. However, methods that embraces both the actual climatic conditions of the engineering project and the need for a relatively quick slake durability analysis are limited.…”

Evaluation of multivariable regression in predicting rock slake durability index

“…The relationship between SDI with dry and saturated density is direct and with n and W is inverse. The results of regression analysis are presented in Table (1) which shows that all these relationships are significant (Sig <0.05). According to Table (1), the relationship between SDI2st with W (R 2 The univariable relationship (95% Confidence intervals) between the SDI (cycles 1 and 2) and mechanical properties is shown in Fig.…”

“…One of the most important geotechnical hazards at the site of hydraulic structures such as dams is the Slake of rock masses due to successive wetting and drying. As a result of this behavior, rock masses become fine fragments and soil [1]. The Slake process occurs in the form of particle dissolution, cracking and scaling of surface layers [2].…”

Durability Assessment of Clay-Bearing Soft Rocks By Using New Decay Index

“…Ricon et al [18] believed that laboratory test on fresh sample overestimate durability behavior of clay-bearing rocks and used microtremor H/V spectral ratio and image entropy techniques to quantify the insitue degrees of disintegration. Heidari et al [19] have assessed suitability of the static and dynamic standard slaking tests for using durability assessment of clay-bearing rocks. Their results showed that the materials retained in the 2 mm mesh drum consists of disintegrated particles varying in diameter and they proposed a sieve analysis of the materials retained.…”