摘要
根–土复合体抗剪强度值是评价土壤抗侵蚀能力的重要指标,受植物生长期、植物种类等因素影响,植物根–土复合体抗剪强度值往往表现出较大程度的变异性。为有效降低这种变异性,在实际研究过程中需开展一定数量的复合体剪切试验,以便合理地确定根–土复合体抗剪强度值大小,以及复合体抗剪强度影响因素的作用程度。为此,开展定量分析不同植物根–土复合体抗剪强度、影响复合体抗剪强度的主要因素,以及复合体抗剪强度指标与各影响因素之间的关系,是亟待解决的关键问题。基于此,本文以生长于柴达木盆地大柴旦盐湖湖滨区的5种盐生植物根–土复合体为研究对象,通过室内直剪试验对上述根–土复合体原状试样进行直剪试验,获得其抗剪强度指标黏聚力c值和内摩擦角j值;通过烘干称重法获得复合体含水率、通过洗根称重法获得其含根量、采用游标卡尺测定法获得其根径。在此基础上,以黏聚力c值、内摩擦角j值、含水率、根径和含根量5项试验值为指标,进一步分析了含水率、含根量和根径3种因素与复合体黏聚力c值和内摩擦角j值的相关性,并采用正态分布、伽马分布、瑞利分布和威布尔分布函数对上述5项指标进行拟合分析,获得了相应分布函数的分布参数;最后采用柯尔莫哥洛夫–斯米洛夫检验(KS test)对上述指标进行分布检验。研究结果表明:复合体5项物理力学性质指标中,含水率与黏聚力c值存在负相关性,含根量与黏聚力c值呈正相关性,其余2项指标(根径、含水率)与黏聚力c值间相关性不显著,且含水率、含根量、根径与内摩擦角φ值间相关性亦不显著;此外,内摩擦角j值服从正态分布和伽马分布,其余4项指标均服从正态分布、伽马分布和威布尔分布;其中,内摩擦角j值最优分布函数为正态分布,黏聚力和含根量最优分布函数为威布尔分
Shear strength indices are key parameters used to assess the anti-scourability of rooted soil. Influenced by factors such as growth period of vegetation,vegetation species type,etc.,values of shear strength indices of rooted soil usually exhibit great variability. To reduce this variability,the shear experiment of rooted soil should be repeated more times to improve the accuracy of shear strength indices and to evaluate the influence factors. However,increasing the number of specimens means extensive damage and disturbance to the ecosystem of grassland,which is frail and vulnerable to be damaged and disturbed. Thus,the priority with reference to specimens is to decrease the number of sampled rooted soil. In this paper,rooted soil of halophytes in salt lake regions of the Daqiadam Lake in Haixi,Qinghai,was selected as the shear test object to obtain the shear strength indices. Oven drying and weighting were used to obtain the moisture content as well as root washing and weighting for the root content,and the root diameter in rooted soil was obtained using a vernier caliper. The correlations between shear strength indices of rooted soil with root content,root diameter and moisture content were analyzed,then,the distribution patterns and the distribution parameters of these physical variables were fitted based on Normal,Gamma,Rayleigh and Weibull distributions,and next KolmogorovSmilov test was used to verify these distribution. The results show that,among the five physical indices,the cohesion has a negative correlation with the moisture content while a positive correlation with the root content,and no obvious correlation exists among other physical indices. It is also revealed that the optimal distributions for internal friction angle,the cohesion and the root content,and the root diameter and moisture content are respectively Normal distribution,Weibull distribution and Gamma distribution. This research contributes to further investigate the factors impacting the shear strength of rooted soil and to explore the i
作者
付江涛
余冬梅
李晓康
刘昌义
胡夏嵩
FU Jiangtao;YU Dongmei;LI Xiaokang;LIU Changyi;HU Xiasong(School of Civil Engineering and Architecture,Shaanxi University of Technology,Hanzhong,Shaanxi 723000,China;Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,Qinghai 810008,China;School of Mathematics and Computer Sciences,Shaanxi University of Technology,Hanzhong,Shaanxi 723000,China;Department of Geological Engineering,Qinghai University,Xining,Qinghai 810016,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第8期1696-1709,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
陕西教育厅基金资助项目(2013JK0987)
国家自然科学基金资助项目(41162010)
第二次青藏高原综合科学考察研究资助(2019QZKK0905–14)。
