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(寧波大學(xué)巖土工程研究所， 寧波 315211)
［摘要］開展了建筑荷載作用下能源樁-土力學(xué)模型試驗及數(shù)值模擬，分析了加熱（制冷）運行對樁土力學(xué)特性的影響。首先，在樁頂分級加載至2kN，待沉降穩(wěn)定后再對樁土進行加熱升溫冷卻(室溫11℃→55℃→11℃)，測試了樁頂豎向位移、樁身軸力、土體溫度和孔隙水壓力、地表豎向位移，分析了循環(huán)溫度作用下的樁-土力學(xué)特性及變化規(guī)律；其次，以模型試驗為原型，利用ABAQUS軟件建立能源樁樁-土計算模型，并將模擬結(jié)果與試驗結(jié)果對比；最后，開展了不同循環(huán)溫度作用和循環(huán)次數(shù)下的樁-土力學(xué)特性數(shù)值模擬。結(jié)果表明：在運行工況下，土中超靜孔隙水壓力隨溫升的增加而變大，使土體發(fā)生熱固結(jié)現(xiàn)象；隨循環(huán)次數(shù)的增加，樁頂及地表產(chǎn)生不可恢復(fù)的變形，且土的沉降大于樁體沉降，導(dǎo)致樁身多處出現(xiàn)負摩阻力，且負摩阻力隨溫度的升高而增大。
［關(guān)鍵詞］能源樁； 模型試驗； 熱力學(xué)特性； 有限元分析； 負摩阻力
中圖分類號：TU473文獻標識碼：A文章編號：1002-848X(2020)07-0136-07
Study on energy pile-soil mechanical characteristics under cyclic temperature and load
QIAN Feng, LIU Ganbin, TANG Yang, XIONG Yonglin, FAN Gaofei, QI Changguang, ZHENG Mingfei
(Institute of Geotechnical Engineering, Ningbo University, Ningbo 315211, China)
Abstract:The model tests and numerical simulations of energy pile-soil mechanical characteristics under the action of building loads were carried out, and the influence of heating (cooling) operation on the pile-soil mechanical properties was analyzed. Firstly, the pile top was loaded to 2kN gradually. After the settlement stabilized, the pile soil was heated and cooled changing（from room temperature of 11℃ to 55℃ and the back to 11℃）. The vertical displacement of the pile top, the axial force of the pile body, the soil temperature, pore water pressure and vertical displacement of the ground surface were tested, the mechanical characteristics and changes of piles-soil under cyclic temperature were analyzed. Secondly, the model test was used as a prototype, and the energy pile-soil calculation model was established by using ABAQUS software. The simulation results were compared with the test results. Finally, numerical simulations of the mechanical properties of the pile-soil under different cyclic temperature and cyclic times were carried out. The results show that: under operating working conditions, the super-static pore water pressure in the soil increases with the temperature rise, which causes the soil to undergo thermal consolidation; as the number of cyclic times increases, the pile top and the ground surface undergo unrecoverable deformation, and the settlement of soil is greater than the settlement of piles, resulting in negative friction resistance in multiple places of the pile body, and the negative friction resistance increases with increasing temperature.
Keywords:energy pile; model test; thermal characteristics; finite element analysis; negative friction resistance
*國家自然科學(xué)基金項目(51478228)。
作者簡介：錢峰，碩士，Email:513761656@qq.com。
