Influence of the Silt Content on Mechanical Properties of Unsaturated Soil Under High Suction
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摘要: 常年处于寒-旱交替、蒸发远大于降水地区的路基边坡土体,大多数时期呈现高吸力非饱和状态。为研究粉粒含量对高吸力非饱和土的土-水特性及强度的影响规律,利用饱和盐溶液蒸汽平衡法对不同粉粒含量土样施加高吸力并进行非饱和土三轴试验和劈裂抗拉试验。结果表明:粉粒含量对非饱和土进水值影响显著,两者呈负相关,粉粒含量升高,土样持水能力下降;粉粒含量和吸力均对抗拉强度具有劣化作用,双因素同时作用引起土体的开裂深度增大。吸力对土样变形具有抑制作用,吸力越高,吸力提供的黏聚力越大。粉粒含量升高对土体弹性模量劣化作用显著,从模量角度定义脆性指数,对粉粒含量影响下高吸力非饱和土的脆性特征进行评价,发现粉粒含量主要通过影响峰后割线模量改变高吸力非饱和土的脆性。Abstract: The soil of subgrade slopes in areas with alternating cold and dry seasons throughout the year, where evaporation is much greater than precipitation, is in a unsaturated state with high suction most of the time. To study the influence of the silt content on soil-water characteristics and strength of unsaturated soil with high suction, the vapor equilibrium method of saturated salt solution was used to apply high suction to soil with different contents of silt, triaxial tests and splitting tensile tests were conducted on unsaturated soil. The test results indicated that:the silt content had a significant effect on the water intake value of unsaturated soil, there was a negative correlation between the two. The water-held capacity of the soil decreased with the increase of the silt content. Both the silt content and suction had a deteriorating effect on the tensile strength, and both factors simultaneously led to increase in the crack depth of soil. Suction had an inhibitory effect on the deformation of soil, the larger the suction was, the larger the cohesion provided by the suction was. The increase in the silt content had a significant effect on the degeneration of soil elastic moduli. The brittleness characteristics of unsaturated soil with high suction influenced by the silt content were evaluated by defining the brittleness index from a perspective of moduli. It was found that the brittleness of unsaturated soil with high suction was altered by the silt content mainly through the influence of the post-peak secant modulus.
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Key words:
- silt content /
- high suction /
- soil-water charateristic /
- tensile strength
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[1] 谢定义.非饱和土力学[M].北京:高等教育出版社,2015. [2] 姜彤,宋陈雨,张俊然,等.广吸力范围内国道G310路基黄土水力力学特性试验研究[J].中国安全生产科学技术,2021,17(7):117-123. [3] VESGA L F, VALLEJO L E. Strength of an unsaturated Kaolinite clay under suction pressures[C]//Proceedings of the 16th International Conference on Soil Mechanics and Geotechnical Engineering,ASCE.2006:1290-1301. [4] 宋锦坡,崔宏环,胡淑旗,等.寒区高吸力非饱和土的破坏准则研究[J].冰川冻土,2022, 44(5):1581-1592. [5] 陈正汉.重塑非饱和黄土的变形、强度、屈服和水量变化特性[J].岩土工程学报,1999(1):85-93. [6] 郭倩怡,谷天峰,吴熠哲.永靖非饱和黄土抗剪强度试验研究[J].水文地质工程地质,2015,42(6):103-107,113. [7] 崔宏环,杨兴然,孙利成,等.冀西北地区非饱和土试验研究及强度预测[J].辽宁工程技术大学学报(自然科学版),2022,41(1):1-6. [8] 黄宇凡,荣传新,施鑫,等.非饱和黏土土体吸力及其对抗剪强度影响试验[J].科学技术与工程,2021,21(25):10859-10866. [9] 汤有志,吴瑞潜,杨光.浙东大运河非饱和粉质黏土抗剪强度特性的试验研究[J].力学季刊,2021,42(2):360-369. [10] 张杰,刘忠玉,张俊然.非饱和豫东粉土水力-力学特性试验研究[J].公路,2021,66(1):292-296. [11] 杨燕,徐佳俊,杨永浩.粒径大小对非饱和尾矿抗剪强度的影响研究[J].地下空间与工程学报,2013,9(4):861-864. [12] 崔宏环,秦晓鹏,王文涛,等. 冻融循环对非饱和粉质黏土SWCC及强度的影响[J].地下空间与工程学报,2020,16(6):1722-1728,1745. [13] 陈宇龙,内村太郎.粒径对土持水性能的影响[J]. 岩石力学与工程学报,2016,35(7):1474-1482. [14] 文宝萍, 胡艳青.颗粒级配对非饱和黏性土基质吸力的影响规律[J].水文地质工程地质,2008(6):50-55. [15] 东南大学,浙江大学,湖南大学,等.土力学[M]. 4版.北京:中国建筑工业出版社,2016. [16] 中华人民共和国交通运输部.公路土工试验规程:JTG 3430-2020[S].北京:人民交通出版社,2020. [17] 叶万军,刘宽,董西好,等.干湿循环下重塑黄土水分迁移试验[J].西安科技大学学报,2018,38(6):937-944. [18] 徐筱.高吸力及低应力下非饱和土的强度和变形特性[D]. 北京:北京交通大学,2019. [19] 龚壁卫,吴宏伟,王斌.应力状态对膨胀土SWCC的影响研究[J].岩土力学,2004(12):1915-1918. [20] 陈晓斌,喻昭晟,周雨晴,等.红层泥质胶结物干缩裂缝深度与间距预测模型[J].岩土力学,2022,43(4):868-878. [21] 《工程地质手册》编委会.工程地质手册[M]. 5版.北京:中国建筑工业出版社,2018. [22] WANG J J, ZHU J G, CHIU C F, et al. Experimental study on fracture toughness and tensile strength of a clay[J]. Engineering Geology, 2007, 94(1/2):65-75. [23] 侯超群,陈欢,孙志彬,等.较大吸力范围内合肥膨胀土强度特性试验研究[J].工业建筑,2020,50(11):78-81,70. [24] 中华人民共和国住房和城乡建设部.土工试验方法标准:GB/T 50123-2019[S].北京:中国计划出版社,2019. [25] 李广信.高等土力学[M].北京:清华大学出版社, 2004. [26] 杨仕教,曾晟,王和龙.加载速率对石灰岩力学效应的试验研究[J].岩土工程学报,2005,27(7):786-788. [27] 胡清波,梁海安,杨婷,等.一种基于统计损伤本构关系的岩石脆性评价新方法[J].哈尔滨工业大学学报,2020,52(11):147-156.
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