Effect of Anti-Slide Piles Anchorage Lengths on Slip Surface and Anti-Slide Capacity of Homogeneous Slope

Abstract:

Visible tests of homogeneous slope reinforced with anti-slide piles with different anchorage lengths were conducted by using transparent soil technique and particle image velocimetry （PIV）， to investigate the evolution of internal displacement field and the failure process of stabilized slope and reveal the effect of anchorage length on slip surface and anti-slide capacity of piles. The results show that with the increase in anchorage length， the slip surface of the reinforced slope gradually deepens and hence the resistance against sliding of the piles increases. However， when the anchorage length exceeds the optimal length， the soil behind the piles move over the pile top and the slip surface gets shallow， which results in the significant decrease of resistance of the anti-slide piles. As the anchorage length of pile is equal to the optimal length， two slip surfaces develop in the slope： a shallow one exiting above the pile top， and a deep one passing through the lower part of the pile. With the increase of anchorage length， the tensile zone of the outside wall in the upper section of the pile narrows but that of the inside wall in the lower section of the pile expands. Meanwhile， the maximum bending moments occur at a pile depth of about 0.4 times the total pile length. However， when the anchorage length is larger than the optimum length， the outside wall in the lower portion of the pile is subjected to tension whereas the inside wall bears tensile force in the upper portion of the pile. At the same time， the maximum bending moment occurs at a pile depth of about 0.35 times the total pile length. The optimum anchorage length is related to the properties of slope materials， pile spacing and stiffness， etc. Therefore， a suitable anchorage length of anti-slide pile should be determined in the project design considering the influence factors mentioned above.