Effect of fıne gravel content on the shear strength of hıgh-plastıcıty clay soil

viEFFECT OF FINE GRAVEL CONTENTON THE SHEAR STRENGTH OFHIGH-PLASTICITY CLAY SOIL(Masters Thesis)Ayşe ÜNVERDGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYSeptember 2006ABSTRACTThe literature contains numerous studies on the shear strength of clays andgravel soils. Yet, a detailed study on the shear strength for clay soils containingdifferent ratios of gravel (c-φ soils) could not be found. Therefore, experimentalφstudies on clay grounds with gravel content was conducted in this work. In themixtures that were used in the experiment, high-plasticity clay was used withfine grain round creek gravel and broken stone was used. Certain geotechnicalcharacteristics of clay and the gravels were established, and these weresubjected to Standard and Modified Proctor experiment. In this way,unconsolidated undrained triaxial compression tests were conducted onsamples prepared with optimum water content and at maximum dry intensity.With the help of these values, samples were prepared for the shear strengthtests. The prepared samples were subjected to undrained shear test in thetriaxial compression test at ambient pressures of 0,5 kgf/cm2, 1,0 kgf/cm2, and2,0 kgf/cm2, and at a loading rate of 0,5 mm/min. in order to define relevantparameters. At the outcome of this experimental study, it was observed thatcohesion decreases and the internal friction angle increases when the ratio ofgravel in the samples increases. While this increase decreases the cohesionvalue, it usually increases the shear strength of the mixture. The shear strengthof the broken stone gravel-clay mixture is found to be higher than creek gravel-viiclay mixture in terms of gravel grains size, its percentage in the mixture, andthe method of compression. It is suggested that the main reason for this can bethat the creek gravel is round and semi-round.Science Code : 911.1.050Keywords : clay, cohesion, granular soil, internal friction angle,shear strength, intermediary soilNumber of Pages : 103Thesis Supervisor : Prof. Dr. Murat MOLLAMAHMUTOĞLU