桩端刺入的离心机试验研究

CENTRIFUGE TEST ON PENETRATION OF PILE TIP

采用可视化模型箱,进行桩端刺入离心模型试验。考虑纯砂土、分层介质两种土体情况,研究上覆软弱夹层对桩端刺入的桩侧摩阻力和桩端阻力的发挥性状及阻力随沉降的发展模式的影响。试验表明:分层介质中达到极限桩端阻力所需的桩端刺入量约为纯砂土中的一半,且当桩土相对位移很小时,桩端附近的土体的横向位移和沿深部方向的影响范围基本形成,桩端砂土有比较明显的椭球孔形扩张态势。

It was investigated the impact of upper weak layer on the behavior of skin friction resistance and pile-tip resistance during pile penetration. Centrifugal tests were carried out to model pile penetration in a uniform sandy ground and a layered ground using a visible soil container. The experimental results showed that the required penetration to mobilize the maximum tip resistance in the layered ground was about half of that in the uniform sandy ground. The lateral displacement of the soil adjacent to the tip was stabilized as well as the influencing depth, when the pile-soil relative displacement was still very small. The sand near the tip exhibited remarkable expansion forming an ellipsoidal hole.