考虑天然黏土应力各向异性的静压沉桩效应研究  

Pile jacking-in effects considering stress anisotropy of natural clay

作　　者：李林[1,2] 李镜培[1,2] 孙德安[3] 岳著文[1,2] 

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092 [3]上海大学土木工程系,上海200072

出　　处：《岩石力学与工程学报》2016年第5期1055-1064,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目（41272288）

摘　　要：基于K0固结各向异性修正剑桥模型（K0-MCC）,考虑天然饱和黏土的初始应力各向异性及应力诱发各向异性特征,推导天然饱和黏土地基中静压沉桩扩孔问题的理论解,提出沉桩阻力的理论计算方法。在此基础上,通过静压沉桩离心机模型试验,对理论解进行验证,研究静压沉桩过程中桩周土压力、孔压及沉桩阻力的变化规律。结果表明,由于提出的理论解合理考虑了天然黏土地基的固有特性,因而可以较好地反映天然饱和黏土中的静压沉桩效应。研究成果为静压桩施工及承载力确定提供了理论依据,具有一定的理论和工程意义。The Cam-clay model modified for the K0-consolidated anisotropic clay,which can properly describe the initial stress anisotropy and stress-induced anisotropy of the natural saturated clay,was used to derive a theoretical solution to the cavity expansion due to pile jacking-in. The method of calculating the resistance of pile sinking is presented. To verify the validity of the theoretical solution,a centrifuge test of pile jacking-in was carried out in K0 consolidated clay. The soil stress,pore water pressure and pile-sinking resistance were studied in detail by comparing the measured data with the predicted data. The results show that the proposed mechanical model reflects the pile jacking-in effects properly due to the intrinsic properties of the natural clay being sufficiently considered. The proposed solution provides a theoretical base for pile construction and bearing capacity determination.

关 键 词：桩基工程 静压沉桩 各向异性 土压力 孔隙水压力 沉桩阻力 离心机试验 

分 类 号：TU473[建筑科学—结构工程]