Study on drivability analysis method of large-diameter steel pipe piles based on CPT
In offshore engineering,large-diameter steel pipe piles are often installed with hydraulic hammers.Accurate analysis of pile drivability is of great significance in practice.In order to study the relationship between cone tip resistance of cone penetration test(CPT)and unit of hammering energy,the resistance to energy ratio was defined as the ratio of unit of equivalent cone tip resistance to unit of hammering energy resistance by converting cone tip resistance into unit equivalent cone tip resistance.Based on 9 sites,72 steel pipe piles driving records and CPT test results,the relationship of resistive energy ratio with depth in different soil layers(silt,sand and clay)was discussed,and a method based on CPT cone tip resistance was proposed.The results show that the variation of unit equivalent cone tip resistance with depth is consistent with that of unit of hammering energy with depth,but the change of resistance to energy ratio with depth in different soil layers are different.The relationship between the resistance energy ratio and depth in different soil layers was obtained,and it was possible to obtain the unit of hammering energy required for pile driving directly from the cone tip resistance of CPT.The method proposed in this paper is verified with an example in practice,and the results show that it is feasible.Because only the CPT cone tip resistance is needed to calculate the unit of hammering energy with the proposed method,it could be used to quickly evaluate the drivability of piles.
large-diameter steel pipe pilescone penetration testunit of hammering energydrivability of pilescone tip resistance