复杂土层HZM/AZ型组合钢板桩施工技术

新加坡某码头工程地基中含有深厚的极密实回填砂层及极硬粉砂土层,其大型HZM/AZ型组合钢板桩打设是施工的难点。对组合钢板桩施工特性进行研究,认为降低锁口阻力是AZ辅桩打设的关键。制定HZM主桩施工精度控制标准,以及先主桩后辅桩的打桩顺序和对辅桩中间锁口位置松土等施工技术措施,大型HZM桩沉桩采用先振动锤振沉再锤击送桩的工艺,并对导向架进行优化设计。结果表明,所有桩顶偏位及高程均满足设计要求,未发现锁口撕裂或脱开情况。

Construction technology of HZM/AZ combined steel sheet pile driving in complicated geologic condition

The foundation contains profound extremely dense backfill sand layer and extremely hard silt soil layer in a port project of Singapore,the large HZM/AZ combined steel sheet pile driving is one of construction difficulties in the project.We study the construction characteristics of the combined steel sheet pile,and find that reducing the interlock friction is the key for AZ auxiliary pile driving.We draw up the HZM pile construction precision control standards,and adopt construction sequence of driving auxiliary pile after main pile and construction measures of soil loosen at the middle interlock position,adopt the technology of installation by vibration hammer first then driving to final level by impact hammer for the large HZM pile driving,and optimize the guide frame design.The results show that the deviation and elevation of all pile tops meet the design requirements,and no tearing or disengagement of interlock is found.