考虑土水吸附效应的黏土收缩曲线方程

doi:10.16183/j.cnki.jsjtu.2019.106

摘要/Abstract

摘要：

在干燥条件下土体逐渐失水产生收缩变形,对土体开裂、地基承载力及边坡稳定性产生重要的影响.因此,有效预测含水量变化下土体的体积收缩变形具有重要的意义.本研究提出了能考虑土水吸附效应的全含水量范围内的土体收缩曲线数学方程.该方程能够同时描述脱湿过程中结构性与非结构性黏土的收缩体变.通过考虑土水吸附效应对土体收缩变形的影响,引入1个参数描述低含水量条件下土体收缩斜率,仅用1个方程即可预测从饱和到干燥条件下土体的完整收缩行为,尤其是低含水量条件下土体的体变特性.通过方程的预测曲线与文献中实测数据的对比,证实了所提出黏土收缩曲线方程的可靠性.同时,与现有方程的预测能力进行对比,表明提出的方程能够很好地描述低含水量条件下黏性土的非0收缩段与非0收缩斜率行为,证实了低含水量条件下土体收缩变形预测中考虑土水吸附效应的必要性与重要性.

关键词: 土体收缩, 体变, 干燥条件, 收缩斜率, 非饱和土, 结构性黏土

Abstract:

Soil shrinkage occurs with the decrease of water content in soils under dry conditions, which has a great influence on soil cracking, bearing capacity, and slope stability. Hence, it is important to predict soil shrinkage effectively under the change of water content in soils. A novel mathematical equation is proposed for describing the soil shrinkage behavior within the full water content range considering the soil-water adsorption effect. The proposed equation can be used to characterize the soil shrinkage behavior of structural and non-structural clayey soils under dry conditions. An additional parameter is introduced into the proposed equation for characterizing the slope of soil shrinkage in low water content ranges, in which the effect of soil-water adsorption is considered. Only one equation is needed to predict the complete shrinkage behavior from saturated to zero water content conditions, especially for describing the volume change of soils under low water content. The proposed equation has been validated by comparing the results between the predicted curves using the proposed model and the measured data in literatures. Comparing with existing equations for soil shrinkage curve, the results show that the proposed equation can describe the non-zero shrinkage and non-zero shrinkage slope behaviors very well under low water content conditions. Furthermore, the results show that the soil-water adsorption effect is important and necessary for prediction of soil shrinkage behavior under low water content conditions.

Key words: soil shrinkage, volume change, dry conditions, shrinkage slope, unsaturated soil, structural clay

中图分类号:

TU443

陈盼, 向锐, 魏小棋, 韦昌富, 王吉利. 考虑土水吸附效应的黏土收缩曲线方程[J]. 上海交通大学学报, 2020, 54(8): 866-872.

CHEN Pan, XIANG Rui, WEI Xiaoqi, WEI Changfu, WANG Jili. Equation for Soil Shrinkage Curve of Clay Considering Soil-Water Adsorption Effect[J]. Journal of Shanghai Jiaotong University, 2020, 54(8): 866-872.

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参考文献 22

[1]	HAINES W B. The volume-changes associated with variations of water content in soil[J]. The Journal of Agricultural Science, 1923,13(3):296-310. doi: 10.1017/S0021859600003580 URL
[2]	唐朝生, 崔玉军, TANG Anh-Minh, 等. 土体干燥过程中的体积收缩变形特征[J]. 岩土工程学报, 2011,33(8):1271-1279.
	TANG Chaosheng, CUI Yujun, TANG Anh-Minh, et al. Volumetric shrinkage characteristics of soil during drying[J]. Chinese Journal of Geotechnical Engineering, 2011,33(8):1271-1279.
[3]	张校通, 郑东生, 夏小和, 等. 非均质饱和-非饱和土的变形特性[J]. 上海交通大学学报, 2012,46(10):1544-1547.
	ZHANG Xiaotong, ZHENG Dongsheng, XIA Xiaohe, et al. Deformation characteristics of non-homogeneously saturated-unsaturated soils[J]. Journal of Shanghai Jiao Tong University, 2012,46(10):1544-1547.
[4]	程演, 张璐璐, 张磊, 等. 基于随机场的非饱和土固结分析[J]. 上海交通大学学报, 2014,48(11):1528-1535.
	CHENG Yan, ZHANG Lulu, ZHANG Lei, et al. Coupled consolidation in unsaturated soils based on random field theory[J]. Journal of Shanghai Jiao Tong University, 2014,48(11):1528-1535.
[5]	刘平, 张虎元, 严耿升, 等. 土建筑遗址表部土体收缩特征曲线测定[J]. 岩石力学与工程学报, 2010,29(4):842-849.
	LIU Ping, ZHANG Huyuan, YAN Gengsheng, et al. Determination of soil shrinkage characteristic curve of surface soil on ancient earthen architectures[J]. Chinese Journal of Rock Mechanics and Engineering, 2010,29(4):842-849.
[6]	汪贤恩, 谭晓慧, 辛志宇, 等. 膨胀土收缩性质的试验研究[J]. 岩土工程学报, 2015,37(Sup.2):107-114.
	WANG Xianen, TAN Xiaohui, XIN Zhiyu, et al. Experimental study on shrinkage properties of expansive soils[J]. Journal of Geotechnical Engineering, 2015,37(Sup.2):107-114.
[7]	LIU X F, BUZZI O. Use of hand-spray plaster as a coating for soil bulk volume measurement[J]. Geotechnical Testing Journal, 2014,37(3):522-528.
[8]	SRIDHARAN A, RAO G V. Effective stress theory of shrinkage phenomena[J]. Canadian Geotechnical Journal, 1971,8(4):503-513. doi: 10.1139/t71-052 URL
[9]	唐朝生, 施斌, 崔玉军. 土体干缩裂隙的形成发育过程及机理[J]. 岩土工程学报, 2018,40(8):1415-1423.
	TANG Chaosheng, SHI Bin, CUI Yujun. Behaviors and mechanisms of desiccation cracking of soils[J]. Journal of Geotechnical Engineering, 2018,40(8):1415-1423.
[10]	BRAUDEAU E, COSTANTINI J M, BELLIER G, et al. New device and method for soil shrinkage curve measurement and characterization[J]. Soil Science Society American Journal, 1999,63:525-535. doi: 10.2136/sssaj1999.03615995006300030015x URL
[11]	CORNELIS W M, CORLUY J, MEDINA H, et al. Measuring and modelling the soil shrinkage characteristic curve[J]. Geoderma, 2006,137(1/2):179-191. doi: 10.1016/j.geoderma.2006.08.022 URL
[12]	邢旭光, 马孝义, 康端刚. 盐阳离子类型及浓度对土壤持水及干缩开裂的作用效果[J]. 农业工程学报, 2016,32(9):115-122.
	XING Xuguang, MA Xiaoyi, KANG Duangang. Impacts of type and concentration of salt cations on soil water retention and desiccation cracking[J]. Transactions of the Chinese Society of Agricultural Engineering, 2016,32(9):115-122.
[13]	LEONG E C, WIJAYA M. Universal soil shrinkage curve equation[J]. Geoderma, 2015,237:78-87.
[14]	FREDLUND M D, WILSON G W, FREDLUND D G. Representation and estimation of the shrinkage curve[C]//Proceedings of the Third International Conference on Unsaturated Soils. Florida: CRC Press, 2002: 145-149.
[15]	PENG X, HORN R. Modeling soil shrinkage curve across a wide range of soil types[J]. Soil Science Society America Journal, 2005,69:584-592. doi: 10.2136/sssaj2004.0146 URL
[16]	BOIVIN P, GARNIER P, VAUCLIN M. Modeling the soil shrinkage and water retention curves with the same equations[J]. Soil Science Society American Journal, 2006,70(4):1082-1093. doi: 10.2136/sssaj2005.0218 URL
[17]	戴明月, 陈勇, 王智炜. 不同初始状态下膨胀土体收缩变形拟合模型[J]. 人民长江, 2018,49(8):83-87.
	DAI Mingyue, CHEN Yong, WANG Zhiwei. A fitting model for shrinkage of expansive soil in different initial states[J]. Yangtze River, 2018,49(8):83-87.
[18]	OLSEN P A, HAUGEN L E. A new model of the shrinkage characteristic applied to some Norwegian soils[J]. Geoderma, 1998,83:67-81. doi: 10.1016/S0016-7061(97)00145-6 URL
[19]	LU N, DONG Y. Correlation between soil shrinkage curve and water-retention characteristics[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2017,143(9):04017054. doi: 10.1061/(ASCE)GT.1943-5606.0001741 URL
[20]	CHEN P, LU N. Generalized equation for soil shrinkage curve[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2018,144(8):04018046. doi: 10.1061/(ASCE)GT.1943-5606.0001889 URL
[21]	MARINHO F A. Fundamentals of soil shrinkage[C]// Second Pan American Conference on Unsaturated Soils Conference Proceedings. Virginia: ASCE Press U.S., 2017: 198-222.
[22]	THYAGARAJ T, THOMAS S R, DAS A P. Physico-chemical effects on shrinkage behavior of compacted expansive clay[J]. International Journal of Geomechanics, 2017,17(2):06016013. doi: 10.1061/(ASCE)GM.1943-5622.0000698 URL

编号	土样	孔隙率	土粒比重	液限/%	塑限/%
1	伦敦黏土	1.30	2.75	77	29
2	伦敦黏土粉土混合	0.90	2.70	43	22
3	膨胀土 1	1.19	2.72	81	25
4	膨胀土 2	1.17	2.72	81	25
5	膨胀土 3	1.01	2.72	81	25
6	蓝黏土	1.04	2.75	63	27
7	挪威黏土	1.10	2.60	-	-

编号	土样	模型参数					相关系数
编号	土样	e₀	α	β	γ	k	R²
1	伦敦黏土	0.423	52.75	72.53	1.02	0.04	0.998
2	伦敦黏土粉土混和	0.475	1.32	5.06	1.32	0.10	0.998
3	膨胀土 1	0.458	7.47	18.49	1.59	0.12	0.998
4	膨胀土 2	0.348	0.64	0.75	2.18	0.24	0.998
5	膨胀土 3	0.454	11.83	40.24	1.50	0.14	1.000

编号	土样	公式	e₀	α	β	a	b	γ	k	R²
1	蓝黏土	(9)	0.530	13.96	77.58	-	-	1.18	0.14	0.997
2	挪威黏土		0.795	0.71	2.89	-	-	2.57	0.11	0.996
3	蓝黏土	(1)	0.544	0.35	1.12	-	-	1.37	-	0.995
4	挪威黏土		0.802	0.25	0.12	-	-	9.56	-	0.989
5	蓝黏土	(10)	0.561	-	-	0.57	5.74	-	-	0.993
6	挪威黏土		0.812	-	-	0.84	3.28	-	-	0.972