Prediction of strength of silty clay-concrete interface under cyclic loading

Based on the 3D scanning and printing technology, the concrete specimens with the same contact surface as the concrete cast-in-place piles are produced, and a series of silty clay-concrete interface cyclic shear tests are conducted. Through the cyclic shear tests on the silty clay-concrete interface, the attenuation laws of interface strength under different cyclic periods and cyclic amplitudes are revealed. By fitting the cyclic amplitude and normal pressure power function, the strength attenuation coefficient of the concrete-soil interface after cyclic stabilization is characterized, and by combining with the peak strength model for the clay-concrete interface, the strength attenuation model for the silty clay-concrete interface is proposed. The results show that the shear displacement-shear stress curves of some cycles coincide approximately after 15 cycles. When the cyclic amplitude increases gradually, the stress-strain curves at the shear stage and unloading stage show a linear trend, and the slopes of loading and unloading in each cycle are basically consistent, similar to "parallelogram". The reduction coefficient D_\tau of the peak interfacial shear strength after cyclic stabilization has the same variation trend under different working conditions. A dimensionless nonlinear regression analysis of cyclic amplitude A and normal stress \sigma can be used to obtain the reduction coefficient D_\tau of the peak interfacial shear strength after cyclic stabilization, which has a high degree of fitting.