表面振动激励下新拌混凝土动力响应与能量传递特征  

Dynamic Response and Energy Transfer Characteristics of Fresh Concrete Under Surface Vibration Excitation

作　　者：马宇航 田正宏[1] 马元山 MA Yu-hang;TIAN Zheng-hong;MA Yuan-shan(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210o98,China)

机构地区：[1]河海大学水利水电学院,江苏南京210098

出　　处：《水电能源科学》2023年第3期157-160,116,共5页Water Resources and Power

基　　金：国家自然科学基金项目(51879094)。

摘　　要：为研究面层振动荷载作用下新拌混凝土内部动力响应与能量传递的时空演变特征,开展了新浇混凝土的室内平板振动密实试验。通过受振混凝土内部不同埋深处加速度传感器获取密实过程中实时动力响应特征参数,采用小波阈值去噪法对振动信号降噪处理,通过测点加速度响应分析新拌混凝土内部运动能量的时空演变规律。结果表明,表面振动源附近集料颗粒以竖向运动为主,宏观尺度下表现为新拌混凝土表面明显沉降;随埋深增加,内部远端颗粒因无法获得充足振动能量,难以克服颗粒间嵌挤力与介质内摩擦阻力而保持初始平衡状态,受振影响小;新拌混凝土振动密实过程中内部颗粒的竖向加速度大于侧向加速度,随着新拌混凝土密实程度的增加,竖向加速度幅值先减小后基本保持不变,侧向加速度幅值先减小后略有增大;振源附近混凝土振动能量衰减幅度最大,但随着埋深增加振动能量衰减不显著。该结论可为新拌混凝土振动密实理论构建及深入研究提供参考。In order to study the temporal and spatial evolution characteristics of internal dynamic response and energy transfer of fresh concrete under the action of surface vibration load, a laboratory vibratory plate compaction test of fresh concrete was carried out. Real-time dynamic response characteristic parameters were obtained by acceleration sensors at different buried depths in the compaction process of vibrated concrete. The vibration signal was denoised by wavelet threshold denoising method. The temporal and spatial evolution law of internal motion energy of fresh concrete was analyzed by measuring point acceleration response. The results show that the aggregate particles near the surface vibration source mainly move vertically, and the surface of fresh concrete is obviously settled on the macro scale. With the increase of burial depth, the internal particles at the far end cannot get enough vibration energy, so it is difficult to overcome the extrusion force between particles and the friction resistance in the medium and maintain the initial equilibrium state, which is less affected by vibration. The vertical acceleration of internal particles is greater than the lateral acceleration during the vibration compaction of fresh concrete. With the increase of the compaction degree of fresh concrete, the vertical acceleration amplitude first decreases and then basically remains unchanged, while the lateral acceleration amplitude first decreases and then slightly increases. The vibration energy attenuation of concrete near the vibration source is the largest, but it is not significant with the increase of buried depth. The work in this paper can provide reference for the theoretical construction and in-depth study of vibration compaction of fresh concrete.

关 键 词：振动密实 新拌混凝土 滤波去噪 动力响应 能量衰减 

分 类 号：TV431[水利工程—水工结构工程] TV537