黑沙蒿与粉土质砂根-土及土-土界面摩阻特性

以鄂尔多斯上湾煤矿塌陷区水土保持先锋灌木之一黑沙蒿和粉土质砂为研究对象,通过直剪试验和根-土复合体单根拉拔试验,探究土壤质量含水率、根径对黑沙蒿根-土界面及土-土界面摩阻特性的影响。结果表明:在土壤埋深72 cm和144 cm左右,2种剪切界面的抗剪强度值均随质量含水率增加呈先增后减趋势;黑沙蒿根-土复合体最大拉拔力与根径呈明显线性正相关,其抗剪强度随根径增加而减小;土壤质量含水率从3.94%增至19.94%,黑沙蒿根-土界面摩擦系数由0.48减至0.38,土-土界面摩擦系数由0.43减至0.35;2种剪切界面的黏聚力随土壤质量含水率增加呈现先增后减趋势,土壤质量含水率为11.94%时,黑沙蒿根-土界面黏聚力峰值为4.51 kPa,土-土界面黏聚力峰值为4.56 kPa。

Friction Characteristics of Root-soil and Soil-soil Interface of Artemisia ordosica and Silty Sand

Artemisia ordosica is a soil and water conservation pioneer shrub in the coal mining subsidence area of Shangwan in Ordos,so we took Artemisia ordosica and silty sand as objective to investigate the effects of soil mass moisture content and root diameter on the friction characteristics of the root-soil interface and soil-soil interface of the Artemisia ordosica. Direct shear test and single root pullout friction test of the root-soil composite were performed. The results showed that the shear strength of the two types of shear interface first increased and then decreased with increase of the soil mass moisture content at soil depth of 144 cm.A strong linear correlation between the maximum pulling force of the Artemisia ordosica root-soil composite and root diameter was noted in the composite test;however,the shear strength in the pulling test decreased with the increase of the root diameter. With increase of the soil mass moisture content from 3.94% to 19.94%,the friction coefficient of the Artemisia ordosica root-soil interface decreased from 0.48 to 0.38,which the soil-soil interface decreased from 0.43 to 0.35. The cohesion of the two shear interfaces first increased and then decreased with the increase of the soil mass moisture content.When the soil moisture content was 11.94%,the maximum cohesion of the Artemisia ordosica root-soil and soil-soil interfaces was 4.51 and 4.56 kPa,respectively.