重载作用受锚边坡动力稳定性分析

Analysis on Dynamic Stability of Soil Slope with Anchor Bolt Reinforcement under Heavy Vehicle Loading

基于重载交通对道路锚固边坡结构的动力响应特性,分析了振动波在土体传播过程中反射、干涉叠加的影响,得到沿坡面垂直向内干涉叠加振动增强的最大影响深度、锚杆设计长度和锚固力补偿值的计算式,且其值与边坡角、坡高、土体密度、锚杆安设角、锚头等效集中质量、自由段长度和波速等因素有关。数值算例表明：考虑重载交通动载响应对边坡垂直位移、水平位移和塑性区范围较静力状态均有所增大,其中水平位移最大值增大40%左右,垂直位移最大值增大32%左右,伴随着塑性区逐渐向锚杆底端扩展,锚杆剪力呈双驼峰分布,且在锚杆底端也有较大的剪力发挥值。为控制动载剪切核的扩展保证边坡稳定最长锚杆设计长度不应小于1.5~2.7倍振动波波长。

Based on the dynamic response characteristics of heavy traffic on anchored slope for road engineering, the reflection and interference superposition on vibration wave propagation process in soil is studied. The formulas of maximum influence depth, design length of anchor bolt and compensation value of anchoring force under the condition of enhanced vibration around interference superposition along the vertical direction inward slope surface are obtained. These values are related to angle and height of slope, soil density, installed angle for anchor bolt, equivalent lumped mass of anchor head, length of free section, wave velocity and so on. The numerical analysis example shows that （ 1 ） the dynamic response of the heavy traffic increased vertical displacement, horizontal displacement, scope of plastic zone compared with those of static state, and the maximum horizontal displacement increased about 40%, the maximum vertical displacement increased about 32%, and the plastic zone gradually expanded to the bottom of anchor bolt, while the distribution of shear along bolt is double hump, with the appearance on larger value of shear stress at the bottom anchor region. To controlled extension of shear core with dynamic loading and ensure slope solidation, the longest bolt length should not less than 1.5 -2.7 times of vibrating wave length.