重塑膨胀土制样长度对试样密度分布的影响
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摘要
在对重塑膨胀土裂隙性问题的单元试验研究中,传统的分层制样法易产生"层间薄弱带",从而影响试验结果的准确性。针对这一问题,采用增加制样高度的单层压实制样方法,探讨了制样高度对重塑膨胀土试样密度的影响。试验结果表明:试样密度沿深度方向变化规律类似,均呈现出顶部大、底部小的分布特征;增加制样高度导致试样顶部与底部密度差及密度变化率发生改变;试样密度变化率随深度分布存在拐点,拐点以上部分密度变化率较小,以下部分较大;随着制样高度的增大,拐点位置向试样下部移动;以拐点位置为基础,初步给出了适合本制样方法的制样高度。
In the unit test research of remolded expansive soil fissure problem, the traditional layering sampling method is prone to produce "inter-layer weak zone", which affects the accuracy of the test results. In order to solve this issue, the influence of sample height on the density change of the remolded expansive soil sample was discussed by using a single layer compacting method with increasing sample height. The experimental results show that the density of the specimen is similar in the direction of depth, the distribution of the density of the specimen is large and the bottom is small. The increase of the sample height leads to a change in the density difference between the top and the bottom of the sample and the density change rate. There is a "density turning point" in the density variation rate of the specimen with the depth distribution, and the partial density change rate above the "turning point" is slower and the following part is faster. As the height of the sample is increased, the position of the "density turning point" moves to the lower part of the sample. Based on the "density turning point" position, a sample preparation height suitable for the sample preparation method is preliminarily presented.
In the unit test research of remolded expansive soil fissure problem, the traditional layering sampling method is prone to produce "inter-layer weak zone", which affects the accuracy of the test results. In order to solve this issue, the influence of sample height on the density change of the remolded expansive soil sample was discussed by using a single layer compacting method with increasing sample height. The experimental results show that the density of the specimen is similar in the direction of depth, the distribution of the density of the specimen is large and the bottom is small. The increase of the sample height leads to a change in the density difference between the top and the bottom of the sample and the density change rate. There is a "density turning point" in the density variation rate of the specimen with the depth distribution, and the partial density change rate above the "turning point" is slower and the following part is faster. As the height of the sample is increased, the position of the "density turning point" moves to the lower part of the sample. Based on the "density turning point" position, a sample preparation height suitable for the sample preparation method is preliminarily presented.
引文
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[2] 陈善雄,戴张俊,陆定杰,等.考虑裂隙分布及强度的膨胀土边坡稳定性分析[J].水利学报,2014,45(12):1442-1449.
[3] 蔡正银,吴志强,黄英豪,等.冻土单轴抗压强度影响因素的试验研究[J].冰川冻土,2015,37(4):1002-1008.
[4] DAGESSE D F.Freezing-Induced Bulk Soil Volume Changes[J].Canadian Journal of Soil Science,2010,90(3):389-401.
[5] 杨钢.非饱和土试样优选及循环荷载作用下的变形特性研究[D].大连:大连理工大学,2013:87-89.
[6] WANG S,LUNA R,STEPHENSON R W.A Slurry Consolidation Approach to Reconstitute Low-Plasticity Silt Specimens for Laboratory Triaxial Testing[J].Geotechnical Testing Journal,2011,34(4):288-296.
[7] 孙凯强,唐朝生,刘昌黎,等.土体龟裂研究方法[J].岩土力学,2017,38(增刊1):11-26.
[8] 中华人民共和国水利部.土工试验方法标准:GB/T 50123—1999[S].北京:中国计划出版社,1999:9-10.
[9] HOTINEANU A,BOUASKER M,ALDAOOD A,et al.Effect of Freeze-Thaw Cycling on the Mechanical Properties of Lime-Stabilized Expansive Clays[J].Cold Regions Science & Technology,2015,119:151-157.
[10] 张家俊,龚壁卫,胡波,等.干湿循环作用下膨胀土裂隙演化规律试验研究[J].岩土力学,2011,32(9):2729-2734.
[11] ALDAOOD A,BOUASKER M,AL-MUKHTAR M.Effect of Water During Freeze-Thaw Cycles on the Performance and Durability of Lime-Treated Gypseous Soil[J].Cold Regions Science & Technology,2016,123:155-163.
[12] GHAZAVI M,ROUSTAEI M.Freeze-Thaw Performance of Clayey Soil Reinforced with Geotextile Layer[J].Cold Regions Science & Technology,2013,89(7):22-29.