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本文对上海某工程场地下粉砂层厚达8m的特点,进行了三组(20根)进入粉砂层不同深度的钢筋混凝土预制短桩的竖直荷载试验,并实测了各级荷载下的桩身轴力。分析试验结果认为,桩端阻临界深度(h_(cp))为10D(D为桩径或边长)临界厚度(t_c)为7.5D、侧阻的临界深度(h_(cs))为10D。通过对桩的荷载传递机理的分析研究,得到了实际桩侧阻安全系数K_f、桩端阻安全系数K_b与桩顶的相对沉降s/D的关系曲线,由此得到了相对于总安全系数K=2时桩的K_f、K_b值以及相应的相对沉降s/D。并利用数理统计方法对K_f～s/D曲线、K_b～s/D曲线进行了回归,供设计参考使用。
In this paper, the vertical load test of three groups (20) of reinforced concrete precast short piles with different depths in the silt layer was carried out for the characteristics of the silt layer thickness of 8m in a project site in Shanghai, and the measured loads at various levels were measured. Pile shaft force. The analytical test results indicate that the critical depth (h_(cp)) of the pile tip is 10D (D is the pile diameter or side length), the critical thickness (t_c) is 7.5D, and the critical depth (h_cs) of the lateral resistance is 10D. By analyzing and studying the load transfer mechanism of the pile, the relationship between the actual safety factor K_f of pile side resistance, safety factor K_b of pile end resistance and the relative settlement s/D of the pile top is obtained, and the relative safety factor K is obtained. The value of K_f, K_b and the corresponding relative settlement s/D of the pile when =2. And using mathematical statistics method to K_f ~ s / D curve, K_b ~ s / D curve regression for design reference use.