Abstract: A plenty of electric transmission lines in the southwest of China cross mountain areas,with their pile foundations located in gravelly soil slope terrain grounds. The m value of horizontal-loaded piles in such foundations is still a challenge in civil engineering. Model tests of horizontal-loaded piles on slopes of four different gradients were conducted to examine the variation of pile displacement with horizontal load and the change of horizontal resistance of pile-side soil along depth direction. The corresponding relationship between the m-value and soil surface displacement can be descried into power function,and the main parameters in the function are in relation to the rate of subgrade reaction of soil in sloping area and level ground. To verify the validity of the proposed equation,an in-situ lateral loading test was performed. The research finding effectively improves the accuracy of calculating horizontal resistance of laterally loaded pile on gravelly soil slope.

Key words: gravelly soil, terrain slope, piles under lateral load, value of m, power function