Experimental Investigation into Physical Mechanism of Side Grouting with Airbag Blocking for DPC Piles

To further improve the side-grouting process of DPC (Drilling and Pipe-Casting) pile, solve the problem of grout leakage in DPC pile side-grouting, and better utilize the existing advantages of DPC pile construction, an experimental study on the airbag sealing process of DPC pile side-grouting was conducted. A scaled model test system was developed to simulate the DPC pile side-grouting process, study the failure modes of airbag sealing, and investigate the influencing factors of different failure modes. The test results showed that the sealing airbag could significantly increase the side-grouting pressure, improve grouting efficiency and quality. Two failure modes of the sealing airbag were identified: overall slip failure and local distortion failure. Technical measures such as increasing the length of the contact section, improving the friction coefficient, and selecting airbags with moderate outer diameter could prevent overall slip failure. Additionally, applying epoxy resin mixture at the loading end of the sealing airbag and increasing flexural stiffness could prevent local distortion failure. The structural design principles of sealing airbags were proposed, leading to the development of a novel DPC pile side airbag sealing grouting technology. The findings of this study can provide reference for DPC pile side-grouting construction.