火山灰沉积地区桩基承载力试验

Test on bearing capacity of bored pile in pozzolana sediment area

针对火山灰沉积地区地质条件的特殊性,通过苏拉马都大桥钻孔灌注桩的自平衡试验和理论分析,对火山灰沉积岩中各土层的承载性状进行了研究。结果表明:火山灰沉积岩中各土层达到极限摩阻力时的桩土相对位移小于20 mm,且侧摩阻力与桩土位移之间可近似拟合为双曲线关系;大直径超长桩在达到极限承载力时桩端承载力值所占比重较大;侧摩阻力的发挥要先于桩端阻力的发挥;火山灰沉积岩中桩的竖向极限承载力控制因素是桩端土的容许承载力和桩顶位移。

Due to the special geological conditions of the pozzolanic sedimentary area,this paper studies the bearing behavior of each layer of the pozzolanic sedimentary rock by using self-balanced load test and theoretical analysis of bored piles of Suramadu Bridge.The results show that: the relative pile-soil displacement is less than 20 mm when all layers reach the limits of its frictional resistance,and the relationship between side friction and pile-soil displacement can be approximated as a hyperbola;when the bearing capacity of large diameter and super-long pile is up to its ultimate,the value of pile-tip bearing capacity accounts for a larger proportion;side friction exerts before the pile tip resistance does.The allowable bearing capacity of pile-tip soil and the displacement of pile-top are the controlling factors of ultimate bearing capacity in the pozzolanic sedimentary rock.2 tabs,6 figs,9 refs.