基于模型试验的齿坎型重力锚抗滑机制

Anti-slide Mechanism of the Notched Sill Gravity Anchorage Based on Model Test

为了探究齿坎型重力式锚碇的承载特性与抗滑机制,依托贵州省牂牁江特大桥纳雍岸重力式锚碇工程,开展了相同试验条件下平底锚碇1/4埋深、齿坎锚碇1/4埋深、平底锚碇半埋深及齿坎锚碇半埋深四种工况的室内物理模型试验,并对各工况锚碇位移-荷载曲线、锚碇-地基接触应力、地基应变及地基宏观变形破坏特征进行分析。结果表明:四种工况锚碇模型的极限承载力分别为3P(平底1/4埋深)、4P(齿坎1/4埋深)、7P(平底半埋深)和8P(齿坎半埋深);同种型式锚碇模型增大埋深可以显著提升锚碇的承载能力,同等埋深条件下齿坎型重力式锚碇承载性能要优于平底重力式锚碇;齿坎构造能够充分调动地基联合承载;基于地基的宏观变形破坏特征将其变形破坏过程划分为无裂隙、裂隙初现、裂隙发展以及破坏四个阶段;对齿坎型重力式锚碇承力过程进行了力学分析,得出齿坎构造力学特性较好,对限制锚碇变位和提高锚碇承载能力作用明显。

In order to explore the bearing characteristics and anti-slide mechanism of the notched sill gravity anchorage,based on the Nayong bank gravity anchor project of the Zangke River Grand Bridge in Guizhou Province,indoor physical model tests were conducted under the same test conditions for four working conditions including flat bottom anchorage with 1/4 buried depth,notched sill anchorage with 1/4 buried depth,flat bottom anchorage with half buried depth,and notched sill anchorage with half buried depth.The curve of anchorage displacement with load,contact stress between the anchorage and the foundation,the strain and macroscopic deformation and failure characteristics of the foundation under each working condition were analyzed.The results show that the ultimate bearing capacity of the four anchorage models under different working conditions is 3 P(flat bottom 1/4 with buried depth),4 P(notched sill with 1/4 buried depth),7 P(flat bottom with half buried depth),and 8 P(notched sill with half buried depth),respectively.The bearing capacity of the same type of anchor model can be significantly improved by increasing the buried depth.Under the same buried depth,the bearing capacity of the notched sill gravity anchorage is better than that of the flat bottom gravity anchorage.The notched sill structure can fully mobilize the joint bearing capacity of the foundation.Based on the macroscopic deformation and failure characteristics of the foundation,the deformation and failure process is divided into four stages,namely no change,initial appearance of cracks,development of cracks,and failure.The mechanical analysis was conducted on the load-bearing process of the notched sill gravity anchorage,and it was found that the mechanical characteristics of the notched sill structure are good,and it has a significant effect on limiting displacement and improving bearing capacity of the anchorage.