Researches on Analyses for Two Special Sets of Pile Loading Tests

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基本資料

Project title

Code/計畫編號

MOST109-2221-E019-016

Translated Name/計畫中文名

兩組特殊樁載重試驗的分析研究

Project Coordinator/計畫主持人

San-Shyan Lin

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Harbor and River Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=13532065

Year

2020

Start date/計畫起

01-08-2020

Expected Completion/計畫迄

31-07-2021

Bugetid/研究經費

649千元

ResearchField/研究領域

土木水利工程

本計畫擬針對兩組特殊的試樁結果進行分析，第一組係植入粉土質砂土層中的植入樁，此樁前後分別執行兩個反覆加卸載的抗壓及拉拔試驗，由於先執行試驗已造成樁/土互制產生永久變位，因此殘存在樁/土介面的殘餘應力(基樁於不同深度埋設有應變計)將影響後執行試驗之結果，計畫執行將探討殘餘應力對後試驗之影響。擬分析的第二個案例係位於砂/黏土互層中的兩支尺寸一樣、位置相鄰的壁樁，其中一支壁樁先進行樁底灌漿再進行樁載重試驗，以比較樁底灌漿對試驗樁承載力之改善成效，本案之分析更具參考價值。分析方法除鋼筋計直接推導法外，另將用反算法求的樁周之極限摩擦阻抗以及樁/土介面之初始剪力模數，及運用數值分析法檢討植入樁之前加載承壓試驗對後續拉拔試驗結果之影響。有限元素法分析軸壓試驗後將保留試驗所造成樁周的摩擦阻抗，這些阻抗變成拉拔試驗的初始條件，同一根樁再進行拉拔試驗，試驗結果再與經鋼筋計推導法求得拉拔試樁後的軸力與樁周摩擦阻抗比較，以了解其間的差異。This proposal is aim to interpret two uncommon pile loading tests. The first set is the pre-bored PC pile subjected to cyclic compression and tension on the same pile. The pre-bored PC pile was installed in silty sand soil. The residual stress along pile shaft due to the applied compressive loading is expecting to affect the performance of the following tensile loading test results. This proposal will focus on how the residual stress affects the results of the subsequent tensile loading test. In the second loading test, two barrette piles, tested at the same site with the same dimension, will be studied in detail on performance of these two piles for the effect of toe grouting improved on one of the piles. Using the measured installed strain gage data from both tests, the secant modulus will be used for interpretation of the test results. In addition, the reverse calculation method will be used to determine the parameters of the pile/soil interface properties, that is assumed as a hyperbolic model. In addition, the back calculation results will also be used to calibrate the material properties for the finite element analysis. The stresses remained along the shaft after the compressive loading will become the initial stress before tensile loading test in the finite element analysis. The numerical results will compare to the results derived by the strain gage data.

Keyword(s)

壁樁
殘餘應力
樁底灌漿
樁載重試驗
植入樁
Barrette
residual stress
pre-bored PC pile
pile loading test
toe grouting

DSpace CRIS

Researches on Analyses for Two Special Sets of Pile Loading Tests

基本資料

Description