Uplift Behavior of Belled Piles Subjected to Static Loading
- PDF / 4,765,073 Bytes
- 17 Pages / 595.276 x 790.866 pts Page_size
- 62 Downloads / 249 Views
RESEARCH ARTICLE-CIVIL ENGINEERING
Uplift Behavior of Belled Piles Subjected to Static Loading Guang Liu1,3,5 · Zhenhua Zhang1 · Qiang Cui2 · Jun Peng3,4 · Ming Cai5,6 Received: 22 February 2020 / Accepted: 5 July 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract The uplift behavior of foundation is of great importance for the construction of foundations of ports, transmission towers and other structures that require to resist uplift loading. This research presents the results of several uplift static loading tests of prototypical belled piles. The load–displacement curve of belled piles is divided into three stages: initial linear segment, middle curve segment, and ending linear segment. The characteristic uplift capacities for the three stages are given by a graphics method. A bi-linear equation is given for predicting characteristic loading capacities of piles based on the ratio of bell to shaft diameters (bb/bs) and the embedment depth (L). Using the calibrated micro-parameters by the load–displacement curves, PFC2D is used to investigate the development of microcracks and formation of soil slip surface in the uplift test. The predicted uplift capacities by simulation can match the experimental value and estimated value by the suggested linear equation. The numerical result shows that the microcracks propagate, connect, and coalesce rapidly once the load–displacement curve reaches the middle curve segment. The final soil slip surface from numerical simulation varies with the geometric dimension of belled piles. The effect of bell to shaft diameters ratio (bb/bs) and embedment depth (L) on the uplift capacity is examined using numerical uplift tests. The result shows that uplift capacity of belled piles can be improved by increasing bell to shaft diameters ratio (bb/bs) and embedment depth (L). Keywords Belled piles · Uplift load test · Load–displacement curve · Microcracks
1 Introduction
* Zhenhua Zhang [email protected] 1
School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
2
Institute of Transmission and Transformation Engineering, China Electric Power Research Institute, Beijing 102401, China
3
Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering, Ministry of Education, Wuhan University, Wuhan 430072, China
4
State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
5
Geomechanics Research Centre, MIRARCO, Laurentian University, Sudbury, ON P3E 2C6, Canada
6
Key Laboratory of Ministry of Education for Safe Mining of Deep Metal Mines, Northeastern University, Shenyang 110004, China
Belled piles, also known as piles with an enlarged base, pedestal piles, and belled piers [1–4], are widely used in foundations of structures such as transmission line towers, ports, and piers that are subjected to external loads. One technique to construct a belled pile is drilling or excavating a cavity at the foundation location and placing a steel tube and concrete to form a st
Data Loading...
