高桩码头桩基负摩擦力现场试验研究 ——上海洋山深水港工程现场试验

高桩码头接岸结构中的桩基础，在抛石的作用下将产生负摩擦力。通过支撑桩及自由桩上负摩擦力的现场试验研究，获得抛石过程中基桩内力随深度变化的基本规律。抛石过程中基桩上的负摩擦力主要产生在抛石段。同时，抛石作为附加荷载，将引起下方软弱土层的固结沉降，桩土之间产生相对位移，从而在抛石段下方一定范围内也产生负摩擦力作用。承台荷载对负摩擦力的大小和分布有着重要的影响。提出的负摩擦力分布规律和采用有效应力法计算层状土负摩擦力的公式，可为桩基础的设计，尤其对水下单面抛石施工的设计及采取消减负摩擦力的措施提供依据。

In-situ tests on negative skin friction of piles in high-piled wharf In-situ test in Shanghai Yangshan Deep Water Port Engineering

The in-situ test on negative skin friction of piles in high-piled wharf is one part of Shanghai Yangshan Deep Water Port Engineering. For piles in link-banked structure of high-piled wharf, rubble-mound may cause negative skin friction on piles. Based on data from in-situ tests on piles (two supporting piles and one free-headed pile), basic laws of pile internal force have been obtained. During rubble-mounting negative skin friction mainly comes from the pile segment which is surrounded by dumped rubble. Meanwhile, rubble-mount as surcharge load induces consolidation of soft sub-soils. Negative skin friction on piles also exists under dumped rubble layer because of the relative displacement between the pile and the sub-soil. The negative friction is also greatly influenced by the load on base slab. The distribution character of negative skin friction and the formula for calculating negative skin friction in layered soils proposed in this paper provide some useful data for pile design; especially, for dumping rubble construction in one side underwater, and for selecting measures to reduce negative skin friction.