本文選題：大比尺模型試驗 + X形樁�。� 參考：《巖土力學(xué)》2016年S1期

【摘要】：實際工程中樁基經(jīng)常受到各種動荷載作用,如高鐵路基中的加固樁長期承受列車行車時產(chǎn)生的循環(huán)動荷載作用,樁基在循環(huán)荷載作用下的承載特性研究對動荷載下的工程設(shè)計至關(guān)重要。X形樁是一種在傳統(tǒng)圓形截面樁基礎(chǔ)上發(fā)展而來的新型異性樁技術(shù),其承載機制不同于傳統(tǒng)圓形截面樁。為了深入研究X形樁在循環(huán)荷載作用下的動力特性和荷載與沉降規(guī)律,開展了砂土中X形樁豎向循環(huán)加載大比尺模型試驗。試驗結(jié)果表明,隨著循環(huán)加載的進行,X形樁頂產(chǎn)生累計沉降,且循環(huán)荷載比越大,加載頻率越高,樁頂沉降越快;循環(huán)加載初期,X形樁頂動剛度降低,樁身軸力響應(yīng)增大,樁側(cè)摩阻力發(fā)生弱化,之后逐漸趨于穩(wěn)定,且樁身下半段側(cè)摩阻力較大;在同等加載條件下X形樁與等截面圓形樁相比,承受動荷載能力較強,樁側(cè)摩阻力較大,長期循環(huán)加載作用下產(chǎn)生的累計位移較小。研究結(jié)果可為X形樁在動荷載作用下的工程設(shè)計提供參考依據(jù)。
[Abstract]:In practical engineering, pile foundations are often subjected to various dynamic loads, such as the reinforcement piles in high-speed railway subgrade, which are subjected to cyclic dynamic loads caused by train running for a long time. Research on the bearing characteristics of pile Foundation under cyclic load; X pile is a new type of anisotropic pile technology developed on the basis of traditional circular section pile, and its bearing mechanism is different from that of traditional circular section pile. In order to deeply study the dynamic characteristics of X-shaped pile under cyclic load and the law of load and settlement, a large scale model test of X-shaped pile under vertical cyclic loading in sandy soil was carried out. The experimental results show that with the cyclic loading, the accumulative settlement of X shaped pile is produced, and the higher the cyclic load ratio is, the higher the loading frequency is, the faster the settlement of the pile top is, the lower the dynamic stiffness of the top of the pile is in the early stage of cyclic loading, the greater the axial force response of the pile body is. The frictional resistance of the pile side becomes weaker, then tends to be stable, and the friction resistance of the bottom half of the pile body is larger, compared with the circular pile with equal section under the same loading condition, the resistance of the X shaped pile is stronger than that of the circular pile with the same section, and the friction resistance of the pile side is larger than that of the circular pile with the same section. The accumulative displacement caused by long-term cyclic loading is smaller. The results can provide a reference for the engineering design of X-shaped pile under dynamic load.
【作者單位】： 河海大學(xué)巖土力學(xué)與堤壩工程教育部重點實驗室;河海大學(xué)土木與交通學(xué)院;重慶大學(xué)土木工程學(xué)院;
【基金】：國家自然科學(xué)基金高鐵聯(lián)合基金重點項目(No.U1134207);； 長江學(xué)者和創(chuàng)新團隊發(fā)展計劃(IRT1125) 國家自然科學(xué)基金(No.51378177)~~
【分類號】：TU473.1

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