深圳大学学报理工版

建立室内模型试验，针对多次温度循环下饱和黏土地基中能源桩热-力响应展开研究，分析了桩周温度场、桩土沉降、桩身附加热应力及侧摩阻力的变化.结果表明，升温时桩身温度沿深度逐渐减小，土体温度沿径向逐渐降低；降温所引起的桩顶沉降量大于升温的膨胀量，将换热液体从5℃加热至70℃并维持24h，随后降温至5℃并维持5h，如此循环3次，导致桩顶产生不可逆的累积沉降；距桩身越近桩周土产生的沉降越大，沉降速率随循环次数的增加呈减小趋势，3次循环后，距桩侧130mm处土体表面沉降达到桩直径的1.42%；温度荷载所引起的桩身附加应力和侧摩阻力均随温度的升高和循环次数的增加而逐渐增大，工作荷载作用下桩身附加热应力最大值达到695.40kPa，最大热应力所在位置随桩顶荷载的增加而逐渐上移；升温时桩体上部产生负的侧摩阻力，下部产生正的侧摩阻力，降温时恰好相反；工作荷载的作用导致桩身产生负摩阻力的区域逐渐变小，位移零点也逐渐上移.

Based on the laboratory model test，the thermal-mechanical response of the energy pile in saturated clay foundation under multiple temperature cycles was studied. The temperature field around the pile，the settlement of pile and soil，the additional heating stress of pile and the shaft friction were analyzed. The results show that the temperature of pile and soil decreases along the depth and radial direction respectively，when the temperature rises. The settlement of pile top caused by cooling is greater than the expansion caused by heating. The heat transfer liquid was heated from 5 ℃ to 70 ℃，then maintained for 24 h，and then cooled to 5 ℃ for 5 h. This cycle for 3 times results in irreversible cumulative settlement of pile top. The settlement decreases with the distance from the pile，and the sedimentation rate of the soil decreases with the increase of the number of cycles. After three cycles，the settlement of soil surface 130 mm away from pile side reaches 1.42% of diameter of pile. The additional stress and the shaft friction of pile caused by temperature load increase gradually with the increase of temperature and number of cycles. The maximum additional heating stress reaches 695.40 kPa under working load，and the value varies with the change of pile top constraint condition，and its position moves gradually upward with the increase of the load on pile top. When heating，the negative shaft friction occurs in the upper part of the pile and the positive shaft friction occurs in the lower part. When cooling，the results are just the opposite. Under the action of the working load，the negative shaft friction area of the pile becomes smaller，and the zero-displacement point moves upward gradually.

引言
1 试验设计
2 结果与分析
3 结论

表1 饱和黏土物理性质Table 1 The physical properties of saturated clay

图1 测点布置（单位：mm） Fig. 1 Layout of measuring points （unit：mm）

图2 荷载-沉降曲线Fig. 2 Load-settlement curve

表2 试验工况Table 2 Test conditions

图3 不同循环温度下桩身温度变化曲线Fig. 3 The change of pile temperature with time in different test conditions

图4 工况4至工况5桩身温度随时间变化曲线Fig. 4 The change of pile temperature with time in the fourth and the fifth conditions

图5 工况4土体温度随时间变化曲线Fig. 5 The change of soil temperature with time in the fourth condition

图6 桩顶位移变化曲线Fig. 6 The displacement of pile top with time

图7 土体表面竖向位移变化曲线Fig. 7 The vertical displacement of soil surface with time

表3 桩身各深度处的监测应变数据Table 3 Observed strains data of piles of different depth

图8 桩身应力-深度分布曲线Fig. 8 The stress distribution along depth

图9 工况1至工况3侧摩阻力沿深度分布Fig. 9 The shaft friction distribution along depth in the first，the second and the third conditions

图10 工况4至工况5侧摩阻力沿深度分布Fig. 10 The shaft friction distribution along depth in the fourth and the fifth conditions

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备注

引言

1 试验设计

2 结果与分析

3 结论

期刊信息

备注

引言

1 试验设计

2 结果与分析

3 结 论

期刊信息

3 结论