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Study on Strength Deterioration of Peat Soil in Freeze-Thaw Cycles
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摘要: 为研究泥炭土在高海拔季节温差作用下其力学特征变化规律,通过室内冻结和冻融下的抗剪强度试验,分析土体在冻结和融化过程中其强度变化规律,并建立冻融循环下泥炭土黏聚力拟合曲线。结果表明:降低冻结温度和延长冻结时间会增强土体抗剪强度,且冻结时间对强度影响更加显著;土体冻融过程中融化阶段对土体强度劣化作用大于冻结阶段的强化作用,含水率越低,这种劣化效应越大;随着冻融次数增加,土体黏聚力对含水率敏感程度降低,而内摩擦角对含水率敏感性增高;含水率为51%~63%是冻融作用和润滑作用对土体黏聚强度的控制阈值;冻融过程强度的劣化既受孔隙水相变的影响,也一定程度上受有机质含量的干扰。冻融次数、含水率与土体黏聚力的关系曲线被拟合,该曲线能够较好预测土体强度的劣化进程。Abstract: To study the mechanical characteristics of peat soil under the action of seasonal temperature differences at high altitudes, through the shear strength tests in freeze and freeze thawing in the laboratory, the strength variation law of soil during freeze-thaw was analyzed, and the fitting curve for cohesion of peat soil in freeze-thaw cycles was obtained. The results showed that reducing freeze temperatures and prolonging freeze times could increase shear strength of soil, and the freeze time had a more significant effect on the strength; in the process of freeze-thaw, the deterioration effect at the thaw stage on soil strength was greater than that at the freeze stage. The lower the water content was, the greater the deterioration effect was. With the increase in rounds of freeze-thaw cycles, the sensitivity of soil cohesion to the water content decreased, while the sensitivity of internal friction angle to the water content increased. The water content of 51% to 63% was the control threshold of freeze-thaw and lubrication for soil cohesive strength; the deterioration of freeze-thaw strength was not only affected by the phase change in pore water, but also affected by the organic matter content. The relation among the round of freeze-thaw cycles, the water content and the soil cohesion was fitted, which could better predict the deterioration of soil strength.
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Key words:
- freeze-thaw cycle /
- peat soil /
- shear strength /
- organic matter /
- deterioration
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[1] 中华人民共和国住房和城乡建设部. 冻土工程地质勘察规范:GB 50324—2014 [S].北京:中国计划出版社,2015. [2] 刘伟,赵福玉,杨文辉,等.安嵩线草海段泥炭质土的特征及性质[J].岩土工程学报,2013,35(增刊2):671-674. [3] 范荣全,唐杨,胡康,等.基于泥炭与冻土共生关系的川西高原泥炭化冻土分布研究[J].湿地科学,2022,20(3):295-302. [4] 王永忠,刘雄军,艾传井,等.南方短时冻土抗剪强度指标c、φ值的试验研究[J].武汉大学学报(工学版),2010,43(2):198-202. [5] 王万平,张熙胤,王义,等.季节冻土区黄土抗剪强度变化特征及其影响因素[J].哈尔滨工业大学学报,2022,54(8):143-150. [6] 李栋伟,汪仁和.冻土抗剪强度特性及试验研究[J].安徽理工大学学报(自然科学版),2004(增刊1):52-55. [7] ALKIRE B D, MORRISON J M. Changes in soil structure due to freeze thaw and repeated loading[J].Transportation Research Record,1983,18(9):15-21. [8] OGATA N, KATAOKA T, KOMIYA A. Effect of freezing thawing on the mechanical properties of soil[C]//Proceedings of the 4th International Symposium on Ground Freezing. Rotterdam: A A Balkema Publishers,1985:201-207. [9] 张玲玲. 冻融循环作用下黄土抗剪强度及微观结构研究[D].太原:太原理工大学,2021. [10] 王天亮,刘建坤,田亚护.冻融作用下水泥及石灰改良土静力特性研究[J].岩土力学,2011,32(1):193-198. [11] 王大雁,马巍,常小晓,等.冻融循环作用对青藏黏土物理力学性质的影响[J].岩石力学与工程学报,2005,23(23):4313-4319. [12] 倪万魁,师华强.冻融循环作用对黄土微结构和强度的影响[J].冰川冻土,2014,36(4):922-927. [13] American Society for Testing and Materials. Standard test method for laboratory determination of the fiber content of peat samples by dry mass: ASTM D1997-91[S]. West Conshohocken, PA, USA: American Society for Testing and Materials, 1991. [14] 中华人民共和国建设部.岩土工程勘察规范:GB 50021—2001 [S].北京:中国建筑工业出版社,2009. [15] 中华人民共和国建设部.土的工程分类标准:GB/T 50145—2007 [S]. 北京:中国计划出版社,2008. [16] LARSEN K S, JONASSON S, MICHELSEN A. Repeated freeze-thaw cycles and their effects on biological processes in two arctic ecosystem types[J]. Applied Soil Ecology, 2002, 21(3): 187-195. [17] 王娇月. 冻融作用对大兴安岭多年冻土区泥炭地土壤有机碳的影响研究[D].长春:中国科学院研究生院东北地理与农业生态研究所, 2014. [18] 裴利华,杨醒宇,桂跃,等.有机质含量及组分对泥炭土物理力学性质影响[J].水文地质工程地质,2022,49(2):77-85. [19] 张泽,马巍,齐吉琳.冻融循环作用下土体结构演化规律及其工程性质改变机理[J].吉林大学学报(地球科学版),2013,43(6):1904-1914. -
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