饱和砂土中高频振动沉桩环境影响机理研究

Study on the environmental impact mechanism of high-frequency vibratory piles driven in saturated soil

近年来,高频振动沉桩因沉桩效率高、环境效应好等优点而得到了广泛应用。但目前高频沉桩仍存在较大理论空白,尤其是高频沉桩较于其他频率沉桩的环境影响机理尚不明确,因此阻碍了工艺的发展。针对该问题,基于有限差分软件FLAC 3D建立了饱和土体振动沉桩数值模型,并从低频到超高频设置若干工况,从而对比验证高频沉桩的优势。结果表明,在避免共振的前提下,选择合适的高频频率,有利于增强桩周土体的孔压响应,促进桩体贯入,同时可有效控制地表振动,提高施工的质量。此外,引入振动桩机免共振施工工艺,可有效避免低频共振现象的发生,进一步减少施工对环境的扰动。

In recent years,high-frequency vibratory piles have been widely used because of their high efficiency and good environmental effect.However,there are still large theoretical gaps for high-frequency piles at present,especially the environmental impact mechanism of high-frequency piles compared with those in other frequencies is still unclear,thus hindering the development of technology.To solve this problem,a numerical model of vibratory pile driven in saturated soil was established based on the finite-difference software FLAC 3D,and several working conditions were set from low frequency to ultra-high frequency to compare and verify the advantages of high-frequency piles.The results show that on the premise of avoiding high-frequency resonance,selecting the appropriate high-frequency is conducive to enhance the pore pressure response of the soil around the pile,thus promoting the pile penetration.Moreover,it can effectively help control the ground vibration,and improve the construction quality.The introduction of resonance-free construction technology for vibratory piles can effectively avoid the occurrence of low-frequency resonance,and further reduce the disturbance to the surrounding environment.