不同升温-降温路径下中空圆柱饱和粉质黏土的热固结

CONSOLIDATION TESTS OF HOLLOW CYLINDRICAL SATURATED SILTY CLAY SUBJECTED TO DIFFERENT HEATING-COOLING PATHS

  • 摘要: 利用自行研制的适用于中空圆柱体试样并可控制试样内、外边界温度的热固结试验装置,进行了一种饱和粉质黏土的热固结试验。温度路径包括试样内、外边界等温单级和多级升温-降温以及内、外边界不等温多级升温-降温,温度荷载的施加范围为25℃~75℃,围压为50 kPa、100 kPa、150 kPa、200 kPa四种情况。论文研究了不同升温-降温路径和不同固结压力条件下饱和粉质黏土的孔隙水压力和固结体应变随时间的演化规律,并对不同温度路径下的试验结果进行了比较。分析表明:同一温度路径下,围压越大,升温或降温所产生的最大归一化孔隙水压力的绝对值越小,固结体应变的大小与围压大小并不成单调关系;同一围压下,升温或降温幅度越大,所产生的最大归一化孔隙水压力的绝对值越大,相应的固结体应变也越大;经过不同温度路径升、降温到同一温度值,设置的温度等级越多,产生的体应变也就越大,并且相同温度等级路径,内、外等温的情况要比不等温情况产生的体应变大。

     

    Abstract: Laboratory tests were conducted to investigate the thermal consolidation behavior of saturated silty clay soils using an axial thermal consolidation test apparatus suitable for saturated hollow cylindrical specimens. Using this apparatus, thermal loadings can be applied on both the inner and outer surfaces of specimens. The temperature paths include isothermal (inner and outer boundaries) single-stage and multistage heating-cooling processes and a non-isothermal (inner and outer boundaries) multistage heating-cooling process. The temperature ranges from 25℃ to 75℃, and the confining pressures are 50 kPa, 100 kPa, 150 kPa and 200 kPa. The evolution of the normalized pore water pressure and consolidation volumetric strain of specimens under different temperature paths and confining pressures are studied. Also the test results under different temperature paths are compared. The results show that the peak normalized pore water pressure (absolute value) induced by heating or cooling decreases as the confining pressure increases under the same temperature path. The consolidation volumetric strain is not a monotonic function of the confining pressure. Both the normalized pore water pressure (absolute value) and consolidation volumetric strain increase with the increase of heating or cooling magnitude under the same confining pressure. Heating or cooling to the same temperature by different temperature paths, the consolidation volumetric strain increases with the increase of temperature grades. The volumetric strain of isothermal multistage process is larger than that of non-isothermal multistage process under the same temperature grades.

     

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