In order to study the fracture behavior of compacted clay,a three-point bending fracture test was conducted using the numerical image correlation method(DIC)on compacted clay samples with different sample sizes,crack lengths,and thicknesses.The fracture behaviors of compacted clay were analyzed,including load displacement curves,fracture toughness(KIC),and length of fracture process zone rc.The experimental results showed that,the displacement load curves of the three samples were consistent in shapes,the peak load increased with the increase of sample size and thickness,while decreased with the increas of crack length;the fracture toughness KIC increased with the increase of sample size,but the amplitude decreased gradually,showing a significant size effect;the fracture toughness KIC increased first and then decreased with the increase of crack length,but the change was not significant.The fracture toughness was considered to be a constant value when the sample thickness was 50～60mm,and the sample thickness had little effect on the fracture toughness KIC.The fracture process zone of large-sized specimens had greater development space,and the prefabricated crack tip stored more energy,which was the main reason for the size effect of compacted clay fracture.The fracture length decreased,while the ligament length increased,which did not increase the length of fracture process zone rc.The thickness of the sample had little effect on the length of the fracture process zone rc.
compacted claytype I fracturefracture toughnesslength of fracture process zone
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