Abstract:

 To reveal the cyclic lateral characteristics of piles in sloping ground under the combined influence of slope effect and cyclic weakening effect, one-way cyclic lateral loading tests with different cycle numbers, load amplitudes and slope angles were carried out, and corresponding lateral static loading tests were conducted as a comparison. The variation trends of pile head deflection, bending moment and subgrade reaction were revealed. Then, the element stiffness matrix was improved by considering the second-order effect and pile-soil interaction to develop the finite beam element solution. Finally, the theoretical predicted curves were compared with measured curves and results calculated by the power series method to validate the finite beam element solution. The results show that the bending moments and pile deflections nonlinearly increase with cycle numbers, and the location of maximum bending moments gradually drops downwards from the non-dimensional depth z_α=1.25 to z_α=1.75. The relationship between the non-dimensional deflection y_0,α atop the pile and cycle number n satisfies the power function y_{0, α}=An^0.11. When the load amplitude increases from 20 N to 40 N, the maximum non-dimensional bending moment increases from 0.010 to 0.029, but their locations remain near z_α=1.7. When the slope angle increases from 30° to 60°, the maximum non-dimensional bending moment increases from 0.011 (z_α=1) to 0.025 (z_α=2.5).

Key words: bridge engineering, pile foundation, cyclic lateral characteristics, model test, slope effect, finite beam element method