复合地基中桩与桩间土应力分配实验

在实验室条件下，用碎石或灰土圆柱芯增强体与黏性土组成的复合地基单位桩模型，通过复合试样的三轴实验模拟现场碎石桩和灰土桩的工作状态，探讨桩与土的相互作用问题。实验结果表明：复合体的竖向强度不是两种材料按一定几何比例简单叠加。复合试样在荷载及应变不大时，桩土应力比增加很快，随后荷载逐渐向桩周土集中，桩土应力比减少。这种规律与现场测试的桩土应力比是一致的。实验揭示了桩土应力比变化规律及其机理。

Stress distribution between pile and soil in composite foundation

The paper discusses a series of triaxial compression tests conducted on compositereinforced soil samples made of clay with the varied length gravel or lime-soil pile for simulating the site soil-pile interaction in laboratories. The experiment reveals that composite sample strength does not mean a simple addition of reinforcing pile and soil according to their replacement proportion. It verifies the principle that in case of a smaller load and strain, stress ratio of reinforcing column to soil increases faster and reaches peak, and then the stress ratio decreases. This law works much as does that of the field measurement.