摘要
Abstract
In response to complex geological conditions such as stone layers of reclamation,muddy composite strata in dynamic water zones,and confined foundation pit spaces,the construction technology of down-the-hole jet high-pressure grouting(DJP)composite pipe piles was studied.The load transfer mechanism and comprehensive applica-tion effects of DJP were studied by numerical simulation and field tests.The results show that the hole formation and pile driving for both the reclamation stone layer and weathered rock layers can be completed in one operation by DJP process.That the synergistic effect of cement-soil external piles and precast pipe piles significantly improved the accuracy of rock-bonding positioning and the consolidation stability of cement-soil in dynamic water zones,and si-multaneously enhanced the horizontal load-bearing capacity and corrosion resistance of the pile foundation.A tech-nology of cement-soil composite pipe pile method+surface ultra-long delivery pile technology has been developed was applied to modular design and a hexagonal head quick-connect mechanism to rapid assemble driver segments within 2 min,overcoming the limitation of delivering piles deeper of 28 m,thus the risks of foundation pit excava-tion was avoided.The core pipe piles(PHC)bear the main vertical load(66％at the top),while the load was trans-ferred to the the surrounding soil by lateral friction resistance for the cement-soil outer piles,forming a three-level force transmission path of core pile → cement-soil → stratum.The characteristics of friction piles was fully lever-aged to increase overall load-bearing capacity by 30％～40％.On-site construction verification shows that the deviation in concentricity of pipe piles is ≤50 mm,and the verticality is ≤0.3％.All key parameters meet the standards,demonstrating significant technical feasibility.The research findings not only solve the technical challenges of pre-fabricated pile construction in complex strata but also provide valuable references for similar projects,with impor-tant application value.关键词
填海淤泥地层/DJP复合管桩/潜孔冲击高压旋喷/超长送桩/荷载传递机理Key words
silty strata of reclamation of/DJP composite pipe pile/down-the-hole jet high-pressure grouting(DJP)/extra-long delivery of piles/load transfer mechanism分类
建筑与水利
