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探寻高效辅助沉桩方法是开口钢管桩桩基工程建设中亟待解决的问题。利用水射流辅助动力沉桩,扰动桩端土体,可有效破除“土塞”、降低地层强度,从而使桩体贯入量达到要求。首先基于射流结构进行主要水力参数介绍;然后结合开口钢管桩桩基建设的土塞问题,对不同结构喷嘴产生的射流流场进行数值模拟,结果表明:等变速型喷嘴作用在土体表面中心处的压力最大,其有限喷距最长。最后通过实验,采用等变速型喷嘴制作的喷头,测试不同强度水射流的破土能力,表明随着水射流强度的增加,沉桩锤击次数减少,破土能力提高。
To explore efficient auxiliary pile driving method is an urgent problem to be solved in the construction of open pipe pile foundation. By using the water jet to assist the pile driving and disturbing the soil at the pile end, the “soil plug” can be effectively eliminated and the formation strength can be reduced, so that the penetration of the pile body can meet the requirements. Firstly, the main hydraulic parameters are introduced based on the jet structure. Then, the jet flow field generated by the nozzle with different structures is numerically simulated based on the soil plug problem of the open pipe pile foundation. The results show that the isokinetic nozzle acts on the center of the soil surface The pressure at the maximum, the limited maximum jet distance. Finally, experiments were carried out by using sprinklers made of equal speed spray nozzles to test the soil breaking ability of water jets of different intensities, indicating that as the water jet intensity increases, the number of pile hammering attacks decreases and the soil breaking capacity improves.