Bearing and uplift capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound finite element limit analysis  

作　　者：Mantu MAJUMDER Debarghya CHAKRABORTY 

机构地区：[1]Department of Civil Engineering,Indian Institute of Technology Kharagpur,Kharagpur 721302,India

出　　处：《Frontiers of Structural and Civil Engineering》2021年第2期537-551,共15页结构与土木工程前沿（英文版）

基　　金：The authors gratefully acknowledge the financial support from ISIRD,SRIC,Indian Institute of Technology Kharagpur(No.IIT/SRIC/CE/PPL/2015-16/108).

摘　　要：Ensuring a safe foundation design in soft clay is always a challenging task to engineers.In the present study,the effectiveness of under-reamed piles in soft clay underlaid by stiff clay is numerically studied using the lower-bound finite element limit analysis(LB FELA).The bearing and uplift capacities of under-reamed piles are estimated through non-dimensional factors N_(cul)and Fcul,respectively.These factors increased remarkably and marginally compared to N_(cul)and Fcul of the piles without bulbs when the bulb is placed in stiff and soft clay,respectively.For a given ratio of undrained cohesion of stiff to soft clay(c_(2)/c_(1)),the factors N_(cul)and Fcul moderately increased with the increase in the length-to-shaft-diameter ratio(Lu/D)and adhesion factors in soft clay(α_(s1))and stiff clay(αs2).The variation of radial stress along the pile-soil interface,distribution of axial force in the under-reamed piles,and state of plastic shear failure in the soil are also studied under axial compression and tension.The results of this study are expected to be useful for the estimation of the bearing and uplift capacities of under-reamed piles in uniform clay and soft clay underlaid by stiff clay.

关 键 词：bearing capacity uplift capacity under-reamed pile CLAY limit analysis 

分 类 号：TU442[建筑科学—岩土工程]