Fractal analysis of the slake durability test

1994 ◽  
Vol 31 (6) ◽  
pp. 1003-1008 ◽  
Author(s):  
Luis E. Vallejo
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Combined Effects ◽  
Durability Test ◽  
Wetting And Drying ◽  
Slake Durability ◽  
Rock Fragments ◽  
Before And After ◽  
Induced Stresses ◽  
Slake Durability Test

Fragments of siltstone were subjected to the slake durability test. The profiles of the rock fragments experienced changes during the test as a result of saturation and abrasion-induced stresses. The profiles of the fragments were evaluated before and after the test using fractal analysis. Fractal analysis uses the concept of fractal dimension to calculate the roughness of profiles. Before the test, the profiles of the siltstone particles had an average fractal dimension equal to 1.1364. After the test, the average fractal dimension of the profiles became equal to 1.1187. The change in fractal dimension was a reflection of the smoothing action on the particle profiles by the combined effects of abrasion and wetting and drying action that take place during the slake durability test. Key words : durability, shape of rock fragments, fractal dimension.

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

2019 ◽  
Vol 79 (4) ◽  
pp. 1919-1937 ◽  
Author(s):  
Lena Selen ◽  
Krishna Kanta Panthi ◽  
Gunnar Vistnes
Keyword(s):  
Rock Mass ◽  
Test Method ◽  
Weak Rock ◽  
Hydropower Project ◽  
Durability Test ◽  
Slake Durability ◽  
Operational Life ◽  
Heterogeneous Rock ◽  
Weak Rock Mass ◽  
Slake Durability Test

AbstractWater tunnels built for hydropower passing through weak and heterogeneous rock mass pose challenges associated to slaking and disintegration, as they are first exposed to dry condition during excavation and are then filled with water to produce hydropower energy. Over the period of operational life, these tunnels are drained periodically for inspections and repair leading to drainage and filling cycles. The weakening of rock mass caused by cycles of drying, saturation and drainage may lead to the propagation of instabilities in the tunnels. Therefore, it is important to study the slaking and disintegration behavior of the weak rock mass consisting of clay and clay-like minerals. This paper assesses the mineralogical composition of flysch and serpentinite from the headrace tunnel of Moglicë Hydropower Project in Albania. Further, to determine the slaking and disintegration behavior of these rocks, extensive testing using both the ISRM, Int J Rock Mech Min Sci Geomech Abstr 16(2):143-151, (1979) suggested test method and a modified variant of this test are performed. Finally, comprehensive assessments, discussions and comparisons are made. It is found that the modified slake durability test better suits for the tunnels built as water conveying systems such as hydropower tunnels.

Controls on shale durability: the response of two Ordovician shales in the slake durability test

1982 ◽  
Vol 19 (1) ◽  
pp. 1-13 ◽  
Author(s):  
D. J. Russell
Keyword(s):  
Durability Test ◽  
Georgian Bay ◽  
Slake Durability ◽  
High Durability ◽  
Calcite Cementation ◽  
Slake Durability Test

The slake durability test has been proposed as a means of predicting the engineering performance of shales. Testing of sections in the two major shale units of Ontario show that the test is capable of making distinctions between apparently similar shale samples. Queenston Shale has generally lower durability than the Georgian Bay Formation samples. Inspection of the shale fabric shows that this is due partly to inefficient cementing by calcite in Queenston Shale, but is primarily because the microcracks in Queenston Shale are more curved than those in Georgian Bay Formation. Variation in shale durability within the shales is controlled by mineralogy. In Queenston Shale, it is controlled almost entirely by calcite cementation. In Georgian Bay, where hard bands (shaly limestone) are present, these dominate the test, giving a high durability. However, pure shale durability is controlled by clay content.Comments on the performance of the test are made that aim to make the testing process and interpretation of the results more reliable. The method appears suitable for shale index testing and should be used as widely as possible in order to establish reliable correlations.

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