含细颗粒的粗粒土SWCC双分形维预测模型  

SWCC bi-fractals dimension prediction model for coarse-grained soils with fine particles

作　　者：刘晓明[1] 杨泽曦 杨刚 涂树杰 LIU Xiaoming;YANG Zexi;YANG Gang;TU Shujie(College of Civil Engineering,Hunan University,Changsha 410082,China;China Communications Road and Bridge Construction Co.Ltd.,Beijing 101107,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]中交路桥建设有限公司,北京101107

出　　处：《华中科技大学学报（自然科学版）》2024年第2期96-102,共7页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家重点研发计划资助项目(2019YFC1904705).

摘　　要：为准确建立含细颗粒的粗粒土土-水特征曲线(SWCC)预测模型,首先,通过对比不同粒度成分土体的孔隙情况,考虑了土体孔隙大、小两种孔径时,SWCC呈双台阶分布的变化规律;然后,基于分形理论,分别计算代表大、小孔径孔隙的两个分形维数,建立了SWCC双分形维预测模型;最后,采用硅藻土-砂混合物实测数据验证了模型准确性,并对6组不同粒度成分土体的实测SWCC进行了预测.结果表明:SWCC双分形维预测模型的拟合优度R2>0.98,预测效果较好.当细粒质量分数为5%~25%时,土体孔隙呈双重孔径分布,SWCC具有两个台阶段,此时,大、小孔隙具有不同的分形维,R2>0.96;当土体细粒质量分数超过25%时,土体孔径分布曲线逐渐呈单峰分布,存在一个使SWCC由双台阶向单台阶转化的界限值,模型可退化为单分形维模型,R2>0.94.To accurately predict the soil-water characteristic curve(SWCC)of coarse-grained soils containing fine particles,the pore conditions of soils with different particle size distribution are firstly compared to reveal the variation patterns of a double-step distribution of SWCC when the pores of soil have two types of sizes,large and small.Then,an SWCC double fractal dimension prediction model was established based on the fractal theory,in which two fractal dimensions were calculated to represent the large and small pore sizes,respectively.Finally,the accuracy of the model was verified using the measured data of diatomaceous earthsand mixtures,and the prediction of the measured SWCC was carried out for six groups of soils with different particle size compositions.The results show that the goodness of fit of the SWCC bi-fractals dimension prediction model is greater than 0.98,and the prediction effect is satisfactory.The soil pores have a double pore size distribution and the SWCC has two stages when the fines content is between 5%and 25%,at this time,the large and small pores have different fractal dimensions,and the goodness of fit of the model is greater than 0.96.The soil pore size distribution curve gradually shows a single-peaked distribution when the soil fines content exceeds 25%,and there is a limit value that transforms the SWCC from a double stage to a single stage.By now the model can be degraded to a single fractal dimensional model,and the goodness of fit is still greater than 0.94.

关 键 词：细粒质量分数 粒度成分 孔径分布 土-水特征曲线 分形理论 

分 类 号：TU441[建筑科学—岩土工程]