考虑桩-岩界面胶结软化特性嵌岩桩沉降计算

Settlement calculation of rock-socketed piles considering softening characteristics of pile-rock bonded interface

基于混凝土-岩石胶结界面剪切力学特性提出桩-岩界面胶结软化荷载传递模型,并与已有的双曲线型模型、非线性软化模型进行对比分析,明确模型中各参数取值方法。随后,基于3种模型编写桩顶沉降量迭代计算程序,根据不同工程地质条件下试桩试验数据验证迭代程序的合理性,并分析各荷载传递模型在不同工程地质条件下的适用性。研究结果表明:提出的胶结软化模型更适用于嵌岩比例较大或完全嵌岩桩荷载传递计算;荷载-沉降曲线随桩-岩界面极限位移比的变化呈现不规则变化,且胶结软化模型受影响程度比其他2种模型的大;随桩顶荷载不断增加,基于胶结软化模型计算出的荷载-沉降曲线受残余侧阻比影响逐渐增大,残余侧阻比越小,桩顶沉降量越大。

The multi-piecewise bonding(MPB) model for pile-rock bonded interface was proposed on the basis of the shear tests results of concrete-rock bonded samples and compared with the existing hyperbolic model and generalized nonlinear softening model. The value of model parameters was determined The iterative computer program based on these three models was developed for analysis of load-settlement calculation. The program rationality was verified by the documented field tests data with different geologic formations. The results show that the proposed MPB model is more suitable for load transfer calculation of rock-socketed piles with large proportion or complete rock-socketed piles. The ultimate relative pile-rock displacement shows a higher irregular effect on load-settlement curves in MPB model than the other two models. Residual ratio of side resistance has the increased effect on load-settlement curves with increasingly external axial load. The settlement calculated by the proposed model increases when the residual ratio of side resistance decreases.