道路工程大直径超深水泥搅拌桩施工技术研究  

Study on Construction Technology of Large Diameter Ultra-deep Cement Mixing Pile in Road Engineering

作　　者：包珍 BAO Zhen(CRCC Harbour and Channel Engineering Bureau Group Co.,Ltd.,Zhuhai Guangdong 519000,China)

机构地区：[1]中国铁建港航局集团有限公司,广东珠海519000

出　　处：《公路交通科技》2022年第11期43-48,共6页Journal of Highway and Transportation Research and Development

基　　金：中国铁建港航局集团2021年科研项目(2021-B24)。

摘　　要：珠江三角洲地区软土深厚,道路工程经常采用50 cm直径的水泥搅拌桩复合地基处理方式。珠海某项目市政道路采用桩径80 cm、桩长约27 m搅拌桩,为工程施工带来了较大难度。为保证工程质量,增加工程经济效益,采取钻头优化方案改进了叶片,由常规的2层4组叶片改进为3层6组叶片,每层叶片投影方向垂直,能增加搅拌次数,提高搅拌均匀度。同时增加双道叶牙,有效增加浆液的流动顺畅程度。优化了喷浆口,由一个喷浆口位于钻头底部喷浆改进为钻杆底端左右两侧喷浆,有效缓解了喷浆口堵塞和淤泥回流。优化了喷浆压力,喷浆压力一般为0.4~0.6 MPa,在第1次搅喷过程中采用上限0.6 MPa,第2次搅喷采用0.4 MPa。优点在于第1次搅拌时先喷出超额水泥浆液进行搅拌,第2次减少喷浆压力可控制总浆液用量,有效提高了桩身质量,并控制了成本。改进了钻杆钻进速度,水泥搅拌桩桩机功率为45~55 kW,施工时钻杆下沉及提升速度控制在0.5~0.8 m/min,下沉时采用上限值,提升时采用下限值,确保加固深度范围内土体搅拌均匀。通过以上措施提高了搅拌桩桩身强度并保证桩体完整。经检测,桩身完整、有效桩径、桩长、桩体强度均符合设计。As the soft soil in the Pearl River Delta area is deep,50 cm diameter cement mixing pile composite foundation is often used for road engineering.A municipal road in Zhuhai City adopts the mixing piles with diameter of 80 cm and length of 27 m,which brings great difficulty to the project construction.In order to ensure the quality and enhance the economic benefits of the project,the optimized scheme of drill bit is adopted to improve the blades,the conventional 2-layer 4-group blades are improved to 3-layer 6-group blades,the projection direction of each layer of blades is vertical,which can increase the mixing times and improve the mixing uniformity.At the same time,double-channel teeth are added to effectively increase the smoothness of slurry flow.The jetting nozzle is optimized from a jetting nozzle located at the bottom of the drill bit to spraying on the left and right sides of the bottom end of the drill pipe,which effectively relieved the blockage of the jetting nozzle and the silt backflow.The jetting pressure is optimized,which is generally 0.4-0.6 MPa,the 0.6 MPa upper limit is used in the first stirring and jetting process,and 0.4 MPa is used for the second stirring and jetting.The advantage is that in the first time of mixing,excess cement grout is sprayed for mixing,and in the second time,the total grout dosage can be controlled by reducing the jetting pressure,which effectively improved the quality of pile body and controlled the cost.The drilling speed of the drill pipe is improved.The power of the cement mixing pile driver is 45-55 kW.During construction,the sinking and lifting speeds of the drill pipe shall be controlled within 0.5-0.8 m/min.the upper limit value shall be used for sinking and the lower limit value shall be used for lifting to ensure that the soil within the reinforcement depth is evenly mixed.Through the above measures,the strength of the mixing pile body is improved and the integrity of the pile body is guaranteed.The testing shows that the pile body is complete,the effective pi

关 键 词：道路工程 技术优化 施工方法 水泥搅拌桩 齿状钻头 

分 类 号：U416.1[交通运输工程—道路与铁道工程]