Abstract: In order to study the fracture toughness K_IC of a remoulded clay, a new apparatus was developed on the basis of the strain-controlling direct shear apparatus, which eliminates the influence of self-gravity of the samples in the traditional three point bending test. A series of experiments are conducted on he remolded clay samples. The experimental results show that the newly developed apparatus is reliable for the measurement of the fracture toughness of soil. For the soil samples with identical moisture content and dry density, the fracture toughness for the samples with U-shaped initial cracks is the greatest and that with triangle initial cracks is the smallest. The moisture content and dry density of soil samples have great effects on their fracture toughness. For the samples with identical dry density, the fracture toughness first increases and then decreases with the increasing moisture content, meaning that there is an optimal moisture content at which the fracture toughness is the greatest. For the samples with identical moisture content, the fracture toughness increases with the increasing dry density. The various loading rates used in this paper have little effect on the fracture toughness.