Friction fatigue on displacement piles in sand
Friction fatigue on displacement piles in sand
复制标题
DOI：
10.1680/geot.54.10.645.56344
复制
发表时间：
2004-12-01
期刊：
影响因子：
5.8
通讯作者：
Lehane, BM
中科院分区：
文献类型：
--
作者：
White, DJ;Lehane, BM
仪器位移桩的实验表明，在给定的砂层中，随着桩尖穿透到更深的水平，可能产生的极限轴摩擦力减小。这种现象，这是现在通常被称为摩擦疲劳，在这里使用离心模型桩配备了横向应力传感器，并从实验室和现场的其他实验数据。结果表明，控制摩擦疲劳的主要机制是在桩安装过程中传递到桩-砂界面处的土元素的循环历史。对于给定的安装方法，作用在位移桩上的任何给定水平的固定侧向应力可以描述为静力锥贯入试验端阻力和安装期间施加的循环次数的相对唯一函数。循环的强烈影响，这也是在循环常数法向刚度界面剪切试验中看到的，是由于收缩的轴-土界面处的一个狭窄的剪切区，周围的土壤具有相对较高的横向刚度。
Experiments with instrumented displacement piles have shown that the ultimate shaft friction that can develop in a given sand horizon decreases as the pile tip penetrates to deeper levels. This phenomenon, which is now commonly referred to as friction fatigue, is investigated here using centrifuge model piles equipped with lateral stress sensors, and by drawing on other experimental data from the laboratory and the field. It is shown that the primary mechanism controlling friction fatigue is the cyclic history imparted during pile installation to soil elements at the pile-sand interface. For a given installation method the stationary lateral stress acting at any given level on a displacement pile can be described as a relatively unique function of the cone penetration test end resistance and the number of cycles imposed during installation. The strong influence of cycling, which is also seen in cyclic constant normal stiffness interface shear tests, is attributed to contraction of a narrow shear zone at the shaft-soil interface that is surrounded by soil with a relatively high lateral stiffness.