全吸力范围红黏土干湿循环土–水特征曲线
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摘要
采用轴平移法、滤纸法以及饱和盐溶液蒸汽平衡法3种方法相结合,对单峰(泥浆土)和双峰(压实土)孔隙结构的重塑红黏土土样进行了一系列室内试验,研究了全吸力范围内(0～286.7 MPa)孔隙结构和初始孔隙比对土–水特征曲线(SWCC)的影响,分析了干湿循环下两种土的滞回性及体积变化规律。试验结果表明:不论泥浆土还是压实土,初始孔隙比对SWCC的影响均主要体现在低吸力阶段;孔隙结构对SWCC影响显著,压实土和泥浆土的SWCC分别呈现"双台阶"和"单台阶"特征;初始孔隙比相同时,泥浆土的进气值更大,持水性能更好;干湿循环下压实土的滞回性明显小于泥浆土,但泥浆土的体变更大。
A series of laboratory tests using the axial translation method, filter paper method and vapor equilibrium method on red clay including a unimodal(slurry) and a bimodal(compacted soil) pore-size distribution are performed to investigate the influences of the initial void ratio and pore structure on the soil-water characteristic curves(SWCCs) in the full suction range of 0～286.7 MPa as well as the hysteresis effect and volume variation during wetting-drying cycles. The test results show that whether the slurry or compacted soil, the influences of the initial void ratio on the SWCCs are mainly reflected in the lower suction range. The pore structure has significant influences on the SWCCs, and the SWCC of compacted soil and slurry are characterized by "double steps" and "single step". The air entry value and water holding capacity of slurry are greater compared to those of compacted soil with the same initial void ratio. The hysteresis effect of the compacted soil is obviously smaller than that of slurry, but the volume variation of slurry is larger during wetting-drying cycles.
A series of laboratory tests using the axial translation method, filter paper method and vapor equilibrium method on red clay including a unimodal(slurry) and a bimodal(compacted soil) pore-size distribution are performed to investigate the influences of the initial void ratio and pore structure on the soil-water characteristic curves(SWCCs) in the full suction range of 0～286.7 MPa as well as the hysteresis effect and volume variation during wetting-drying cycles. The test results show that whether the slurry or compacted soil, the influences of the initial void ratio on the SWCCs are mainly reflected in the lower suction range. The pore structure has significant influences on the SWCCs, and the SWCC of compacted soil and slurry are characterized by "double steps" and "single step". The air entry value and water holding capacity of slurry are greater compared to those of compacted soil with the same initial void ratio. The hysteresis effect of the compacted soil is obviously smaller than that of slurry, but the volume variation of slurry is larger during wetting-drying cycles.
引文
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[3]谈云志,孔令伟,郭爱国,等.压实红黏土的持水性能与机制分析[J].岩土力学,2011,32(S1):334-338.(TANYun-zhi,KONG Ling-wei,GUO Ai-guo,et al.Analysis of water holding capacity and mechanism of compacted laterite soil[J].Rock and Soil Mechanics,2011,32(S1):334-338.(in Chinese))
[4]SUN D A,YOU G,ZHOU A N,et al.Soil-water retention curves and microstructures of undisturbed and compacted Guilin lateritic clay[J].Bulletin of Engineering Geology&the Environment,2016,75(2):781-791.
[5]BURTON G J,PINEDA J A,SHENG D C,et al.Microstructural changes of an undisturbed,reconstituted and compacted high plasticity clay subjected to wetting and drying[J].Engineering Geology,2015,193:363-373.
[6]GAO Y,SUN D A,ZHOU A N.Hydro-mechanical behaviour of unsaturated soil with different specimen preparations[J].Canadian Geotechnical Journal,2016,53(6):909-917.
[7]LIU X,BUZZI O,YUAN S,et al.Multi-scale characterization of retention and shrinkage behaviour of four Australian clayey soils[J].Canadian Geotechnical Journal,2016,53(5).
[8]LEONG E C,HE L,RAGARDJO H.Factors affecting the filter paper method for total and matric suction measurements[J].Geotechnical Testing Journal,2002,25(3):1-12.
[9]GREESPAN L.Humidity fixed points of binary saturated aqueous solutions[J].Journal of Research of the National Bureau of Standards,1977,81(1):89-96.
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