基于Hoek-Brown准则嵌岩段桩-岩侧阻力修正计算方法  

Modified method for shaft resistance of rock-socketed piles based on Hoek-Brown criterion

作　　者：戴国亮[1,2] 龚维明[1,2] 陈隆[1] 

机构地区：[1]东南大学土木工程学院,江苏南京210096 [2]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096

出　　处：《岩土工程学报》2012年第9期1746-1752,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50908048)

摘　　要：利用二维Hoek-Brown(2002)破坏准则为岩石破坏标准,基于"小孔扩张理论"模拟嵌岩段桩侧摩阻力的"剪切-滑移-膨胀"发挥机理,综合考虑了桩体单元受到桩径发生改变后由于岩体的径向约束作用而产生的法向应力,以及土、岩体由于重力的作用产生的竖向应力导致的桩体表面的水平向法向应力,对已有文献推导出来的桩侧极限摩阻力计算进行了修正,并通过算例分析讨论了桩身轴力、岩石强度模数、岩体抗拉强度系数、岩桩刚度比、桩径以及嵌岩比等因素对极限侧阻力的影响。结果表明:嵌岩段极限侧阻力随单桩轴力增大而增大;嵌岩段极限侧阻力与岩石强度模数和岩体抗拉强度系数相关;嵌岩段极限侧阻力与岩桩相对刚度呈正相关;桩径的增加,桩极限侧阻力减小;随嵌岩比增大,传递到桩端的荷载减小,嵌岩段极限侧阻力减小。Using the two dimensional Howk-Brown criterion as the rock failure one, the horizontal normal stresses resulted from the variation of pile diameter under restriction of surrounding rock and the self weight of soil and rock penetrated by piles are considered based on the mechanism of shear-slip-dilation. A modified method for calculating the ultimate shaft resistance of rock-socketed piles is put forward based on the methods in the literature. The affecting aspects are analyzed, including the axial ~brce, the rock strength modulus, the tension strength coefficient, the ratio of rock modulus to pile modulus, the pile diameter and the ratio of socket depth to pile diameter. The results indicate that the ultimate shaft resistance of rock-socket piles increases with the increase of the axial load, the rock strength modulus and the tension strength coefficient and the ratio of rock modulus to pile modulus. It decreases with the increase of the pile diameter and the socket ratio.

关 键 词：嵌岩桩 侧阻力 HOEK-BROWN准则 剪切-滑移-膨胀 

分 类 号：TU473[建筑科学—结构工程]