基于室内模型试验的锚拉式挡土墙力学特性研究

为了研究锚拉式挡土墙在非极限状态下土压力分布及墙体位移变化规律,从力学角度分析了锚拉式挡土墙的作用机理,并基于加筋原理揭示了设置锚杆具有提高墙背土体强度的作用。设计制作了室内模型试验装置,开展了一系列不同预应力水平、不同竖向荷载及二者耦合作用的室内试验。通过分析试验数据,得到了不同影响因素下的土压力合力变化规律及合力作用点位置。结果表明:锚拉式挡土墙由于锚杆的侧向约束作用,墙背土压力峰值出现在锚杆位置处; 分级施加竖向荷载,墙身呈现底部位移略大的平动模式(T模式)外倾; 分级施加锚杆预应力,墙身呈现底部位移略大的向外平动位移模式(T模式); 二者耦合作用下,墙体呈平动叠加绕墙底转动模式(T+RB模式)内倾,但位移量较小; 墙背土压力在预应力、竖向荷载及二者耦合作用下均介于静止土压力与被动土压力之间; 所得结论对工程实践具有指导意义。

Study on Mechanical Properties of Anchored Retaining Wall Based on Indoor Model Test

In order to study the distribution of soil pressure and wall displacement of anchored retaining wall in non-limit state, the mechanism of anchor retaining wall was analyzed from the view of mechanics. Based on the principle of reinforcement, it was explained that the setting of anchor bolt increased the strength of wall back soil. The indoor model test equipment was designed and a series of laboratory tests with different prestress levels, different vertical loads and their coupling effects were carried out. By analyzing the test data, the variation law of soil pressure resultant and the position of resultant point were obtained. The results show that the anchored retaining wall is affected by lateral restraint of bolt and the peak pressure of the wall back soil appears at the position of anchor. The wall body presents a translational mode(T mode)with a slightly larger displacement at the bottom under applying vertical loads in stages. The wall presents a lateral displacement mode(T mode)with a slightly large bottom displacement. When they are coupled, the wall body presents tilting inward in the translational superposition rotating mode around the wall(T+RB mode), but the displacement is small. The pressure on the wall back soil is between the static soil pressure and the passive soil pressure under the prestress, vertical load and their coupling action and the stress peak value. The research results are of guiding significance to engineering practice.