桩端后注浆PHC管桩原理及工程应用

Mechanism and Application of Pile⁃end Post⁃grouting PHC Pipe Pile

PHC管桩具有承载力高、施工速度快、施工质量好和工程造价低的优点,因此在工程建设中得到广泛应用。但是受制于地基承载力,PHC管桩的桩身强度往往得不到充分发挥,造成资源浪费。桩端后注浆是提高地基承载力非常有效的方法。首先,利用PHC管桩空腔设置注浆管,在桩端安装具有注浆功能的桩尖,在PHC管桩中形成注浆回路;然后,将PHC管桩沉桩到位;最后,通过注浆回路向PHC管桩桩端压注高压水泥浆,加固桩端和桩侧土体,达到提高地基承载力和桩基承载力的目的。为了实现PHC管桩桩端后注浆,开发了注浆器内置式注浆桩尖。试验研究和工程应用表明,注浆器内置式注浆桩尖技术是可行的,桩端后注浆PHC管桩具有工艺简单、设备简易、效果显著和成本低廉的优点。

PHC pipe pile has the advantages of high bearing capacity,fast construction speed,good construction quality and low project cost.Therefore,it is widely used in engineering construction.However,due to the bearing capacity of the foundation,the strength of the PHC pipe pile is often not fully utilized,resulting in a waste of resources.Pile⁃end post⁃grouting is a very effective method to improve the bearing capacity of the foundation.Firstly,the grouting pipe is set up by using the cavity of the PHC pipe pile,and the pile tip with grouting function is installed at the pile end to form a grouting loop in the PHC pipe pile.Then,the PHC pipe pile is piled in place.Finally,the high⁃pressure cement slurry is injected into the PHC pipe pile end through the grouting circuit to reinforce the soil at the pile end and the pile side to improve the bearing capacity of both the foundation soil and the pile foundation.To realize the post⁃grooming of the PHC pipe pile end,the built⁃in grouting pile tip of the grouting device is developed.The experimental research and engineering application show that the built⁃in grouting pile tip of the grouting device is technically feasible,and the post⁃grouting PHC pipe pile has the advantages of a simple process,simple equipment,remarkable effect and low cost.