排土场土体裂缝区植被根系及抗剪强度分布特征

Distribution Characteristics of Vegetation Root System and Shear Strength with Ground Fissure in a Dump

为揭示排土场土体裂缝区植物根系和抗剪强度分布特征,采用根钻法、WinRHIZO根系分析系统和直剪仪研究了0—60 cm土层植物根系、黏聚力和内摩擦角随土层深度的变化规律。结果表明:3个样地根系特征参数不同,随土层深度增加而减小,主要分布在0—20 cm土层,根密度和根重密度为88.81~303.03个/10^(3)cm^(3),0.15~2.69 mg/cm^(3)。根系以径级d≤0.1 mm和0.1 mm<d≤0.3 mm为主,占总量的34.79%,40.99%;草本植物以须根为主,数量多且质量轻;各根系特征参数之间呈正相关关系,与土层深度呈显著负相关关系。3个样地土壤黏聚力和内摩擦角为5.56~45.51 kPa和21.69°~31.67°;黏聚力随土层深度的增大表现为先增大后减小,最大值出现在30—40 cm土层,位于土体裂缝深度以下;黏聚力和内摩擦角均随土壤含水率的增大而衰减,黏聚力与土壤含水率之间具有极显著的指数函数关系,而内摩擦角与土壤含水率的关系未达到显著水平;土壤含水率对黏聚力的衰减作用显著大于内摩擦角。

In order to reveal the distribution characteristics of plant roots and shear strength with ground fissure in a dump,the variation of root system,cohesion and internal friction angle of 0—60 cm soil layer were studied by using root drill method,WinRHIZO root analysis system and direct shear apparatus.The results showed that the roots of the three plots mainly distributed in 0—20 cm soil layer,which decreased with the increase of soil depth,and the root density and root weight density of the three plots were 88.81~303.03 roots/103 cm^(3) and 0.15~2.69 mg/cm^(3),respectively;the diameters of plant roots of the three plots were mainly d≤0.1 mm and 0.1 mm<d≤0.3 mm,accounting for 34.79%and 40.99%of the total,respectively;fibrous roots were the main root systems of herbaceous plants,which were abundant in quantity and light in quality;there was a positive correlation between root characteristic parameters and was a significant negative correlation between root characteristic parameters and soil depth;the soil cohesion and internal friction angle of the three plots were 5.56~45.51 kPa and 21.69°~31.67°;with the increase of soil depth,soil cohesion increased at first and then decreased,and the maximum appeared in the 30—40 cm soil layer,which was below the depth of the ground fissures in the soil;cohesion and internal friction angle attenuated with the increase of soil water content;there was a very significant exponential function relationship between cohesion and soil water content,while the relationship between internal friction angle and soil water content was not significant;the attenuation effect of soil water content on cohesion was significantly greater than the internal friction angle.