摘要
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。
Since silty sand stratum of 8-meter thinkness exists in a construction site in Shanghai, three groups of pile loading tests were carried out with the pile tip penetrating different depths of silty sand stratum and the axial forces of piles were measured. From testing results it is found that the critical depth of point resistance (h_(cp)) is 10D, (D: the edge length of pile), the critical thickness of the stratum is 7.5D and the critical depth of shaft resistance of pile (h_(cs)) is also 10D. The K_f-and K_b-(s/D) curves are derived from analysing the loadtransfer mechanism of piles, where K_f is safty-factor of shaft resistance of piles, K_b is saftyfactor of point resistance of piles and s/D is the relative settlement of piles. As a result, K_f, K_b values and corresponding s/D values are also obtained for the total salty-factor of piles K=2. K_f and K_b-s/D regressive curves are obtained by using mathematical statistics. It is hoped that these may prove to be of some usefulness in practical designing.
出处
《建筑科学》
1990年第4期36-42,共7页
Building Science
