Investigation disintegration behavior of clay-bearing rocks under field conditions

Clay-bearing rocks are highly sensitive to atmospheric conditions and rapidly reveal disintegration under these conditions. Engineering projects such as road slopes, where such rocks are located, are often subjected undercutting problems. Up to now, various rock fall problems caused loss of life and property have been encountered in many countries, particularly in the United States, due to the rapid disintegration and erosion of clay-bearing rocks. Such type of instability directly related to undercutting rate of clay-bearing rocks has sudden and high-speed characteristics, and it is more dangerous for highway slopes that have been serving for many years. The direct measurement or prediction of undercutting rate of clay-containing rocks is very important for the safety of the related projects in terms of predetermination of undercutting based instabilities and take required measures in advance. Therefore, it is aimed in this thesis to measure undercutting rate of clay-bearing rocks under field conditions and to determine the relationship between this parameter and other index and physical properties of clay-bearing rocks. For this purpose, 11 different locations in which clay-bearing rocks were found and undercutting problems were observed in the road slopes were selected as the study area. In these road cuts, the depths of undercutting in many locations were obtained by measurements taken at different dates from the nails placed in the fresh of clay-bearing rocks. In addition, the depth of undercutting depth was directly taken by using the amount of erosion between durable rock unit and the clay-bearing rock in the road slopes with known date of excavation. Samples having suitable amount and sizes were collected at the measured locations to be used in physical and durability tests of clay-bearing rocks. In this study, geotechnical properties (e.g., slake durability, Atterberg limits) of clay-bearing rocks were taken into consideration in prediction undercutting rate. In the analyses, the applicability of the results of slake index and slake durability tests as well as the disintegration ratio (DR) in the determination of the disintegration behavior of clay-bearing rocks were investigated. As a result of these analyses, statistically significant empirical equations were obtained to be used to estimate undercutting rate, and it was determined that the approach of "disintegration ratio (DR)" can be used to predict the disintegration behavior of clay-bearing rocks.