抗滑桩锚固长度对均质边坡滑动面及抗滑能力影响研究

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

摘要:

利用透明土技术开展不同锚固长度抗滑桩加固均质边坡可视化模型试验，并结合粒子图像测速技术（PIV），展现抗滑桩加固均质边坡内部位移场演化及其滑移破坏过程，以揭示锚固长度对均质边坡滑动面和抗滑能力的影响机理。研究结果表明：抗滑桩加固边坡的滑动面深度随抗滑桩锚固长度的增加而加深，同时抗滑能力得到提高，但当锚固长度超过其最优锚固长度后滑动面变浅，表现为越顶破坏，使得抗滑桩抗滑能力大幅降低；当抗滑桩锚固长度达到其最优锚固长度时，出现靠近桩底端位置和越顶的两个深浅不一的滑动面；随着锚固长度的增加，抗滑桩上部外侧受拉区减小，而下部内侧受拉区增大，最大弯矩位置均在距桩顶约0.4倍桩长处，而当锚固长度超过其最优锚固长度后，则出现下部外侧受拉而中上部内侧受拉，其最大弯矩位置在距桩顶约0.35倍桩长处；抗滑桩最优锚固长度与岩性、桩间距、桩体刚度等因素相关，在实际工程设计中应考虑这些因素以确定优化的锚固长度。

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.