礁灰岩地区钢管桩沉桩的控制要点*

礁灰岩作为一种海洋生物成因的特殊岩土介质，所包含的土骨架颗粒多孔隙、形状不规则、易破碎、软硬交互，其工程特性与常规岩土存在较大差异，关于该地质条件下的沉桩施工经验也相对匮乏。针对礁灰岩地质条件下钢管桩的沉桩施工所遇到的停锤控制难的问题，从标贯试验、室内土工试验、施工参数以及高应变试桩等方面探讨沉桩的控制要点，提出入岩深度应作为沉桩停锤的控制指标，同时执行分区域沉桩提高工作效率，通过高应变试桩为每个划分区域定制标准桩长，为每个区域沉桩提供参考。

Key control points of steel pipe pile driving in coral-reef limestone area

As a cause of special marine geotechnical medium,the frame work structure of coral-reef limestone is in stratum soft and hard interacted,of which the breakable particles are more porosity and irregular in shape.These characteristics of coral-reef limestone cause significant difference compared to the conventional geomaterial,and steel pipe pile driving is lack of practical experience in this ground condition.When and how to stop the hammer is difficulty in the construction of steel pipe piles under reef limestone geological conditions,so we discuss the key control points of pile driving from some aspects,such as the standard penetration test,soil laboratory test,pile driving parameters and high strain pile test.We propose that embedded depth in limestone should be added as dominant control factor,and driving in sub-regional strategy can improve the work efficiency.Standard pile length of each region can be determined by high strain pile test,which is used as guidance for this region.