基于自平衡试桩法大直径嵌岩桩尺寸效应分析

基于自平衡测试技术，通过现场的原位测试方法，对大直径嵌岩桩的尺寸效应进行了研究，内容包括桩径尺寸和嵌岩深度变化以及桩端阻力尺寸效应的影响分析等。从测试结果来看，嵌岩桩也存在一定程度的尺寸效应现象。当其他条件一定时，随着桩径的增大，桩侧阻力存在着减小现象；在同一种岩层的情况下，随着嵌岩深度的增大，桩侧阻力发挥也并不相同，嵌岩深度越大，桩侧阻力发挥也越小。实测结果表明，桩周岩石的特性变化对桩侧阻力影响最大，岩石抗压强度越高，桩侧阻力也越大。此外，桩径的变化对桩端阻力的影响更为明显。因此，在大直径嵌岩桩的设计中应注意尺寸效应对桩基承载力的影响。

Analysis of size effect on large diameter rock-socketed pile based on self-balance method

Based on the self-balanced test technology,the size effect on the large diameter rock-socketed pile has been analyzed by using in-situ testing methods,including the change of diameter,the depth socketed in rock and size effect on tip resistance of pile and so on.From the result of test,it can be seen that it exit a certain phenomenon of the size effect on the large diameter rock-socketed pile.With the increasing of pile diameter,the side resistance is decreased while other conditions are invariable.From the socketed depth point of view,the side resistance of pile is not the same in the case of the same rock areas because of the difference of its socketed depth.The greater the depth embedded in rock,the smaller the side resistance of pile.The experimental results show that the character of the rock around the pile has the greatest impact on the pile side resistance.The higher the compressive strength of rock,the side resistance of pile is also greater.In addition,the effect of diameter change on the pile tip resistance is even more apparent.Therefore,the design of large diameter pile should pay attention to the size effect on the bearing capacity in rock areas.