在既有建筑的加固改造过程中,桩基础是既有建筑地基基础加固改造或托换的重要手段,但是常规的设备和工艺往往无法满足在既有建筑内部低净空条件下大桩径、大桩长、高承载力桩基础的施工要求。针对此类需求,将锚杆静压桩技术和水泥土复合桩技术相结合,提出低净空下旋喷静压复合桩技术,并研发了旋喷静压一体化成套设备。通过现场足尺试验,验证了该项技术施工工艺的可行性,并通过现场试验对旋喷静压复合桩、旋喷桩及静压桩的施工工艺、单桩承载力、桩身内力等进行了对比分析,试验证明:与传统的静压桩、旋喷桩相比,旋喷静压复合桩的承载力大幅提高。

In the process of reinforcing and renovating existing structures, pile foundations play a pivotal role in foundation enhancement, renovation, or underpinning of buildings. Alas, conventional equipment and methodologies frequently fall short in fulfilling the construction requirements of pile foundations characterized by large diameters, lengths, and high load-bearing capacities, especially under the constraints of low internal headroom conditions within existing buildings. To address these specific demands, anchor jacked pile technology and cement-soil composite pile technology is integrated, subsequently leading to the development of low-clearance jet grouting jacked composite pile technology and a comprehensive set of jet grouting jacked integrated equipment. The feasibility of this state-of-the-art approach has been substantiated through extensive full-scale field tests, which have also allowed for a comparative evaluation of the construction techniques, individual pile load-bearing capacities, and internal pile forces for jet grouting jacked composite piles, rotary jet grouting piles and jacked piles. The experimental results emphasize that jet grouting jacked composite pile technology exhibits a considerably enhanced bearing capacity in comparison to traditional jacked and jet grouting piles, thus indicating its potential in effectively tackling the challenges associated with reinforcing and renovating pre-existing structures.