兩種飽和土中樁基側(cè)向動力響應(yīng)特性試驗研究*
李雨潤1,2，羅祥1，張中樂1，袁曉銘3
- 摘 要
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（1 河北工業(yè)大學土木工程學院， 天津 300401；2 河北省土木工程技術(shù)研究中心， 天津 300401；3 中國地震局工程力學研究所， 哈爾濱 150080）［摘要］自從2008年汶川地震以來，對于飽和砂礫土液化問題的研究一直是巖土工程界與地震工程領(lǐng)域關(guān)注的熱點。本文基于振動臺試驗，通過輸入不同的臺面波形，對飽和砂土和砂礫土側(cè)向動力響應(yīng)特性進行對比分析研究。以試驗成果為基礎(chǔ)，對樁基在飽和砂土與砂礫土兩種不同液化土中側(cè)向動力響應(yīng)特性的異同也進行了初步探討。研究結(jié)果表明：飽和砂礫土具有與飽和砂土類似的液化現(xiàn)象和特點，隨著振動輸入，飽和砂土孔壓先逐漸升高然后又逐漸降低至低水平，而飽和砂礫土在初期迅速升高，而隨后的殘余孔壓沒有明顯減低并一直保持較高水平至振動結(jié)束；飽和砂土土表加速度衰減速度要明顯快于飽和砂礫土，在降低時刻上飽和砂礫土明顯滯后于飽和砂土，說明飽和砂礫土較飽和砂土具有較強的抗液化能力；正弦波輸入下飽和砂土中承臺加速度隨著孔壓升高先增大后減小然后又緩慢升高，而飽和砂礫土中承臺加速度僅經(jīng)歷了先升后降的簡單過程，飽和砂土中樁頭加速度在振動初期的放大倍數(shù)要低于砂礫土，而在振動輸入后期，飽和砂土樁頭加速度要比飽和砂礫土中放大效果明顯，承臺位移響應(yīng)時程則表現(xiàn)出極為相似的規(guī)律，地震波輸入下的反應(yīng)與正弦波略有不同。［關(guān)鍵詞］飽和砂土; 砂礫土; 液化; 孔隙水壓力; 樁基; 土表加速度中圖分類號：TU435 文獻標識碼：A 文章編號：1002-848X(2013)23-0100-05Experimental study of lateral dynamic response characteristics of pile foundation in two kinds of saturated sandsLi Yurun1, 2, Luo Xiang1, Zhang Zhongle1, Yuan Xiaoming3(1 College of Civil Engineering, Hebei University of Technology, Tianjin 300401, China; 2 Civil Engineering Technology Research Center of Hebei Province, Tianjin 300401, China; 3 Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China)Abstract: Since the 2008 Wenchuan earthquake, the study of liquefaction of saturated gravel soil was always concerned in the geotechnical engineering field and the earthquake engineering field. Based on the shaking table test and different shaking table waveforms input, the lateral dynamic response characteristics of saturated sand and gravel soil were analyzed and compared. With the basis of the above experimental results, the differences and similarities of lateral dynamic response characteristics of the pile in the saturated sand and gravel soil were preliminary explored. The research results show that the liquefiable phenomena and characteristics of pile in the saturated gravel soil are analogous to the saturated sand. With the vibration input, the pore pressure of saturated sand increases gradually at first, and then gradually reduces to a low level, while that of the saturated gravel soil increases rapidly in the early, and the subsequent residual pore water pressure do not significantly reduce and maintains a high level with the vibration ending. The acceleration of soil surface in saturated sand decays much faster than that in the gravel soil, and the reducing time of gravel soil lags behind the sand, so it shows that saturated gravel soil has a stronger anti-liquefaction capacity than the saturated sand. With the sine wave input, the cap acceleration in the saturated sand increases at first, and then decreases, and increases slowly finally with the pore pressure increasing. While it in the saturated gravel soil only rises at first and then drops a simple process, the magnification of pile head in the saturated sand is lower than in the saturated gravel sand in the initial stage of vibration. But the amplification effect of pile head acceleration is more obvious than in the saturated sand in the late stage of vibration input. Cap displacement response exhibites very similar law, while the reaction with seismic wave input is slightly different from it with sine wave input.Keywords: saturated sand; gravel sand; liquefaction; pore water pressure; pile foundation; soil surface acceleration*國家自然科學基金資助項目(51008110)，河北省自然科學基金資助（E2013202118），河北建設(shè)廳項目（2007-223）。作者簡介：李雨潤，博士，副教授，Email:iemlyr7888@163.com。參考文獻［1］李雨潤，袁曉銘，曹振中.液化土中樁基礎(chǔ)動力反應(yīng)試驗研究［J］.地震工程與工程振動，2006，26(3)：257-260.［2］孫銳，袁曉銘，李雨潤，等. 循環(huán)荷載下液化對土層水平往返變形的影響［J］.西北地震學報，2009，31（1）：8-14.
