Field testing study on jacked pile penetration characteristics in laminated clay based on FBG sensing technology

In order to analyze the change of static pressure pile characteristics in silt and silty clay with the penetration depth, two PHC pipe piles were penetrated in the field in the actual project, and the research was based on the full section test technology and FBG test technology. The results show that the pile pressure increases with the increase of the pile penetration depth; The change of pile tip resistance is affected by the soil layer hardness; When the pile tip is in the transition stage, the pile tip resistance increases significantly; In the process of pile penetration, the hardness and brittleness of the soil layer will be affected by the pile penetration, and the different soil layers will have different effects on the pile tip resistance of the two piles; When the pile goes deep into the soil, the pile side resistance will change slowly, but it will usually increase. This fluctuation is related to the difference of the soft and hard layers of the soil layer, and will also be subject to performance constraints; The pile end resistance ratio in hard soil will be smaller than that in soft soil, which will further affect the load sharing ratio of the test pile. The test results can provide support for practical engineering technology.