Comparative Study on Shearing Characteristics of Contact Surface between Clay and Timber

In order to study shearing characteristics of contact surface between clay and timber,direct shear test and simple shear test are separately conducted on the interface between clay and timber with original and refitted DSJ-2 electric quadruple iso-strain direct shear apparatus,and comparative analysis is also made.The result shows that under simple shear test,shearing strength on interface between clay and timber,i.e.shear displacement curve is inflexible in initial stage and composes of strain hardening section,strain softening section and plastic flow section after nonlinear elasticity stage.Under direct shear test,shearing strength is in hyperbolic relation.On that basis,this paper puts forward the conversion formula of interface shearing resistance index(interface shearing resistance index shall multiply the coefficient less than 1 under direct shear test) to correct direct shear test result in design.