关键词: 沉桩工艺, 钢管桩, 高频免共振锤, 沉桩原位试验, 位移

Abstract: The construction of traditional pile foundation is featured by environmental pollution, soil squeezing effect, low efficiency and high energy consumption. In an attempt to tackle these problems, the deformation characteristics and vibration of pile's surrounding soil during pile sinking and those of a high-rise bridge pier during adjacent subway running were investigated via in-situ pile sinking test and field vibration test. The resonance-free hydraulic vibratory hammer system was adopted for pile sinking test. Results demonstrated that the horizontal displacement of soil around the pile during pile sinking concentrated in the range of 0-2/3L(L represents pile length) near the ground surface, and in particular, the horizontal displacement in the range of 0-1/4L below the surface was very large. The maximum horizontal and vertical displacement of surrounding soil was 2.37 mm and 3.13 mm, respectively, and the inclination of the pier was 0.4‰-0.7‰. The soil squeezing effect was not obvious during the pile sinking. Field vibration test results showed that the maximum peak velocity was 0.823 mm/s in the absence of subway running, while in the presence of subway running, the peak velocity was 1.90 mm/s, which indicates that the impact on the surrounding environment is weak during pile sinking.

Key words: pile driving process, steel pipe pile, high frequency resonance-free hammer, in-situ pile sinking test, displacement