The coaxial rigid-flexible compound pile (CRFC pile),used for deep soft soil improvement,is comprised of short and large-diameter flexible pile coaxially inserted with rigid pipe pile.According to the field tests,the variations of axial force of CRFC pile,pile-soil load share ratio,surface settlement,and deep lateral displacement with embankment loading and time were investigated,and the comparison was made with drainage consolidation method and cement mixing pile.The following conclusions can be obtained:① the load transfer mechanism of large-diameter flexible pile in CRFC pile is different from that of individual flexible pile,and the bearing properties of CRFC pile can be uniformly mobilized along the entire pile shaft,which can reduce the negative skin friction;② the loading in the early stage of embankment filling is mainly supported by the soil between piles,and the soil pressures between piles are gradually transferred to the CRFC pile,however,the loading transfer is not obvious as the embankment loading is small;③ comparing with other treatment methods,the total settlement and differential settlement of CRFC pile composite foundation are smaller,and the settlement convergence is faster,in addition,the subsidence mainly occurs during the filling period,while the settlement around the end of rigid pile in CRFC pile accounts for about 64％ of the total settlement.%刚柔组合桩是一种新型的复合地基技术,是将刚性桩与柔性桩组合形成复合地基共同承担上部荷载的桩型.依托台州港临海(头门)港区疏港公路试验段,针对大直径双向水泥搅拌桩与预应力管桩同体组合的刚柔组合桩,对刚柔组合桩的桩身轴力、桩土荷载分担比、地表沉降、深层水平位移等进行了系统研究;并与排水固结法、水泥搅拌桩和直接堆载法进行了对比分析.通过试验研究得出以下结论:①刚柔组合桩中大直径柔性桩的荷载传递机制区别于其单独采用,桩体通长承载性能均得到充分发挥,且其设置方式有效减少了刚性芯桩的负摩阻力;②路堤填筑初期荷载主要由桩间土承担,且填筑期内桩间土压力逐渐向刚柔组合桩转移,然而路堤荷载较小时,荷载转移不明显;③与其他处理方式相比,刚柔组合桩复合地基的总沉降量和工后沉降量小,且沉降收敛快,沉降主要发生在路堤填筑期,刚性芯桩桩端沉降占总沉降的比例达63.9％.
展开▼
