抗压桩与抗拔桩受力特性的现场破坏性试验

为理清抗压桩与抗拔桩受力特性的异同,基于2根抗压桩和2根抗拔桩的现场破坏性试验,研究了抗压桩、抗拔桩的侧阻和端阻的发挥特性.现场破坏性试验表明:抗压桩的桩端位移-桩端力曲线表现为软化特性;不同土层中抗拔桩与抗压桩极限侧阻的比值平均为0.373～0.763,深部土层中两者比值较小;抗压桩和抗拔桩桩长范围内的桩侧阻力均表现为软化特性,不同土层中抗拔桩、抗压桩侧阻破坏比分别为0.87～0.97和0.83～0.94;抗拔桩和抗压桩侧阻完全发挥时的桩土相对位移分别约为桩径的0.6%～1.5%和0.9%～2.0%. 

Destructive Field Test on Properties of Uplift and Compression Piles

To clarify the similarities and differences of properties of uplift and compression piles, the mobilizations of skin friction and tip resistance were analyzed based on destructive filed tests on two uplift piles and two compression piles. The destructive field test results showed that under a destructive load, there was a softening relationship between pile tip displacement and load. The average limit skin frictions of the uplift piles were about 0.373 to 0.763 times those of the compression piles, and larger values were found in deep soils. The skin friction degradation along the pile depth was observed. The failure ratio of skin friction was from 0.87 to 0.97 and 0.83 to 0.94 for the uplift and compression piles, respectively. The relative pile-soil displacements for fully mobilizing the skin frictions in different soils were 0.6% to 1.5% and 0.9% to 2.0% of pile diameter for the uplift and compression piles, respectively.