The freezing-thawing deformation behaviors of consolidated soils under high pressure have been investigated in a high-pressure-low-temperature （HPLT） Kq consolidation apparatus with a small strain sensor. The tests...The freezing-thawing deformation behaviors of consolidated soils under high pressure have been investigated in a high-pressure-low-temperature （HPLT） Kq consolidation apparatus with a small strain sensor. The tests cover a variety of frozen soil temperatures ranging from -2℃ to -10 ℃, and a series of applied pressures ranging from 1 MPa to 5 MPa. The test results show that, for the consolidated soils under high pressure, their freezing-thawing deformation was caused by the realignment and the deformation of soil particles, the phase change of water, and the water redistribution in the soil. As for the deformation produced by thermal expansion and contraction,it is about 0.04-0.05 mm, accounting for only about 7%~9% of the total deformation. Taking the freezing-thawing deformation produced by temperature disturbance as a creep deformation, the creep models of the developing soil deformation will be determined by the soil＇s final temperature, i.e., the desired temperature. For the soils under a desired temperature between -2℃ and -5℃, the freezing-thawing de-formation develops according to a non-attenuation creep model; but for the soils with a desired temperature lower than -5℃, a full attenuation creep model is followed. The applied pressure and soil type also have a significant influence on the maximum freezing deformation. Generally, the greater the desired pressure applied, the less the maximum deformation is; and the loess freezing deformation is larger than that of sand.展开更多
新疆南疆盐渍土地区水盐干湿循环作用和冻融循环作用对其道路路基路面结构的变形破坏具有决定性的作用,为了探究干湿循环、冻融循环环境和行车荷载顺序耦合作用下道路水泥土稳定基层变形机理,开展了试验研究与数值模拟分析。考虑试样在...新疆南疆盐渍土地区水盐干湿循环作用和冻融循环作用对其道路路基路面结构的变形破坏具有决定性的作用,为了探究干湿循环、冻融循环环境和行车荷载顺序耦合作用下道路水泥土稳定基层变形机理,开展了试验研究与数值模拟分析。考虑试样在行车荷载、干湿循环作用和冻融循环作用的变耦合影响,以研究对象道路现场监测获得的路基水稳层部位含盐量量,及不同季节的温度变化作为模拟,实验水-盐-温环境控制依据;对制作的路基路面水稳层试样开展静荷载作用与无荷载作用两种条件下的两种工况的变形试验研究。实验测定水稳层试样弹性模量(18 k N/mm2)和泊松比(0.18),根据相似理论建立试验模型,对数值模拟分析结果和试验结果对照分析获得了:干湿循环作用后荷载与冻融循环耦合作用(工况2)试验的试样变形量要比无荷载作用的冻融循环(工况1)试验的试样变形量大,其中工况2在总循环的中期阶段试样变形增量明显高于工况1,其余阶段二者变形增量基本一致;工况2试验的试样变形结果与其数值模拟分析结果较为一致,通过试验确定出了特定条件下路基水稳层膨胀方程。该研究结果可为新疆南疆盐渍土环境道路工程病害防治提供理论基础和科学依据。展开更多
基金supported by a grant from the National Natural Science Foundation of China(No.41671069,No.41630636)Foundation of the State Key Laboratory of Frozen Soil Engineering(SKLFSE-ZT-31)
文摘The freezing-thawing deformation behaviors of consolidated soils under high pressure have been investigated in a high-pressure-low-temperature （HPLT） Kq consolidation apparatus with a small strain sensor. The tests cover a variety of frozen soil temperatures ranging from -2℃ to -10 ℃, and a series of applied pressures ranging from 1 MPa to 5 MPa. The test results show that, for the consolidated soils under high pressure, their freezing-thawing deformation was caused by the realignment and the deformation of soil particles, the phase change of water, and the water redistribution in the soil. As for the deformation produced by thermal expansion and contraction,it is about 0.04-0.05 mm, accounting for only about 7%~9% of the total deformation. Taking the freezing-thawing deformation produced by temperature disturbance as a creep deformation, the creep models of the developing soil deformation will be determined by the soil＇s final temperature, i.e., the desired temperature. For the soils under a desired temperature between -2℃ and -5℃, the freezing-thawing de-formation develops according to a non-attenuation creep model; but for the soils with a desired temperature lower than -5℃, a full attenuation creep model is followed. The applied pressure and soil type also have a significant influence on the maximum freezing deformation. Generally, the greater the desired pressure applied, the less the maximum deformation is; and the loess freezing deformation is larger than that of sand.
文摘新疆南疆盐渍土地区水盐干湿循环作用和冻融循环作用对其道路路基路面结构的变形破坏具有决定性的作用,为了探究干湿循环、冻融循环环境和行车荷载顺序耦合作用下道路水泥土稳定基层变形机理,开展了试验研究与数值模拟分析。考虑试样在行车荷载、干湿循环作用和冻融循环作用的变耦合影响,以研究对象道路现场监测获得的路基水稳层部位含盐量量,及不同季节的温度变化作为模拟,实验水-盐-温环境控制依据;对制作的路基路面水稳层试样开展静荷载作用与无荷载作用两种条件下的两种工况的变形试验研究。实验测定水稳层试样弹性模量(18 k N/mm2)和泊松比(0.18),根据相似理论建立试验模型,对数值模拟分析结果和试验结果对照分析获得了:干湿循环作用后荷载与冻融循环耦合作用(工况2)试验的试样变形量要比无荷载作用的冻融循环(工况1)试验的试样变形量大,其中工况2在总循环的中期阶段试样变形增量明显高于工况1,其余阶段二者变形增量基本一致;工况2试验的试样变形结果与其数值模拟分析结果较为一致,通过试验确定出了特定条件下路基水稳层膨胀方程。该研究结果可为新疆南疆盐渍土环境道路工程病害防治提供理论基础和科学依据。
