The use of methylene blue test for predicting swell parameters of natural clay soils

Abstract

Swell behavior of clayey soils is referred to as a hidden disaster causing a great deal of damage in light hydraulic structures. In this context, it is of key importance to make a preliminary soil research and to identify soils of this nature through lab tests in order to adopt the correct design strategy. It is extremely important to have determined the swell parameters (swell percentage and swell pressure) in designing light hydraulic structures on swelling soil. In our country, these types of problems that are experienced in light hydraulic structures have been observed generally in construction works of irrigation channels carried out within the framework of Southeastern Anatolia Project. In this study, we examine the facts based on the methylene blue stain test data used in predicting swell parameters of Harran clay soils. Within the frame of the study, methylene blue tests have been carried out besides identification tests; working on undisturbed samples taken from thirty three different points by means of drilling, in an area where irrigation channels are laid intensively. Depending on relevant swell parameters, models developed are based on multiple regression analysis for practical use. In the models developed depending on dry density of soil and methylene blue value, R2 values are found to be R2 = 0.93 and R2 = 0.85 for swell percentage and swell pressure, respectively. In view of the fact that the tests that measure swell parameters are long and costly, these models would be very useful to be able to obtain a preliminary estimate rapidly. Key words: Harran clay, methylene blue stain test, swell percentage, swell pressure, multiple regression analysis.