顺层岩质边坡抗滑桩弯折破坏模型及试验研究

Study on flexural failure model of anti-slide pile for bedding rock slope and its experiment

悬臂式抗滑桩是边坡工程有效防护手段,由于岩土体介质及滑坡结构的特殊性,其在滑坡推力及锚固反力共同作用下的桩身力学行为有待进一步研究。基于顺层岩质边坡的地质结构特性及顺层滑移模式,对抗滑桩锚固段的桩后土体抗力进行分析,分别考虑土体抗力为矩形、三角形和梯形分布情况,建立悬臂式抗滑桩力学模型,研究抗滑桩在顺层边坡滑坡推力及土体锚固反力共同作用下的弯折破坏位置,得到了抗滑桩锚固段弯折破坏位置与抗滑桩的长度、埋深以及滑移面的剪切力的关系及其表达式。通过试验对模型进行验证,对抗滑桩的理论弯折破坏位置进行实际对比。结果表明:在此种滑移模式下,悬臂式抗滑桩的锚固反力按梯形分布计算时,理论模型计算结果与试验结论有较好的一致性,而在按照矩形或三角形分布计算时,理论结果与试验结论相差较大。所以,在施工设计过程中,应在计算得出的悬臂式抗滑桩弯折破坏位置布置较密的抗弯钢筋或按最不利条件计算最大弯矩,确保抗滑桩的承载能力满足要求。

As cantilever anti-slide pile is an effective engineering protection means for slope,the mechanical behavior of its body under the common effect between landslide thrust and anchorage reaction force is necessary to be further studied due to the particularities of rock-soil medium and landslide structure.Based on the characteristics of geological structure of bedding rock slope and the pattern of bedding-slip,the soilresistance behind the anti-slide pile within its anchoring section is analyzed,and then the mechanical model of cantilever anti-sliding pile is established and then the position of flexural failure of the anti-slide pile under the common effect between landslide thrust of bedding slope and the anchorage reaction force of soil mass is studied by considering the soilresistance as rectangular,triangular and trapezoidal distributions respectively,thus the relationship among the position of flexural failure of the anti-slide pile,the length and embedded depth of the anti-slide pile and the shearing force of slip plane as well as its expressionformulaare obtained.This model is verified through the model experiment concerned,in which the theoretical position of flexural failure of the anti-slide pile is actually compared.The result shows that under this pattern of bedding-slip,the theoretical model calculation result is better coincided with that from the experiment conclusion when the anchorage reaction force of cantilever anti-slide pile is calculated according to the trapezoidal distribution,while the difference between the theoretical result and the experiment conclusion is larger when the calculation is made in accordance with rectangular or triangulardistribution.Therefore,during the construction design,more dense anti-flexural reinforcement is necessary to be arranged at the position of flexural failure of the anti-slide pile or the maximum bending moment is necessary to be calculated according to the most unfavorable condition,so as to ensure that the bearing capacity of the anti-slide pile can meet the relevant requirement.