倾斜基岩条件下轨道交通振动衰减规律研究

Study on the vibration attenuation caused by rail traffic under sloping bedrock condition

通过模型槽试验和有限元相结合的方法,研究了在倾斜基岩条件下高架轨道交通引起地表振动的衰减规律,分析倾斜角度、荷载频率、桩长对地面环境振动的影响。结果表明:倾斜基岩条件下,地表振动衰减快慢呈现出方向差异化,一般沿基岩倾斜正下方衰减最慢,沿正上方衰减最快,并从正下方到正上方衰减逐渐变快。基岩层倾角越大,地面振动响应越小,基岩倾角变化对地面振动响应的方向差异化影响较为显著。随着荷载频率的增加,地表响应速度先线性增加,然后增速变缓;当频率为13Hz时,与桩等距离各方向振动响应差异最大。地表速度响应随桩长增加呈线性减小,且距桩越近减小越快;桩长变化对与桩等距离各方向振动响应差异影响并不明显。

The attenuation law of ground vibration of viaduct rail transit under sloping bedrock condition is studied by model test and finite element method. The effects of inclination angle, load frequency, pile length on ground vibration were analyzed. The results indicated that under the condition of inclined bedrock, the attenuation of ground vibration is different in directions. Generally, the attenuation is the slowest along the downward slope of bedrock, while the fastest along the upward slope. The attenuation is gradually faster from the downward to the upward;The greater the inclination angle of bedrock layer, the lower the ground vibration response. The change of bedrock angle has a significant influence on the directional differentiation of ground vibration response. With increase of load frequency, the vibration response of the ground increases linearly first then decreases gradually. When the frequency is 13 Hz, the differentiation of vibration response on the ground is the greatest in all directions at the same distance to the pile. The surface velocity response decreases linearly with the increase of pile length. The nearer the pile, the faster the decrease. The influence of the change of pile length on the vibration response in all directions with the same distance to the pile is insignificant.