排水沟边坡分层土直剪及与土工织物摩擦试验研究

Comparative Study on Shear Strength of Drainage Ditch Slope Soil and Its Friction Coefficient with Geotextile

为研究含水率对农田排水沟边坡土抗剪强度的影响,对取自边坡顶层、中层、底层的5种不同含水率的试样在不同正应力下进行不固结不排水快剪试验,研究其抗剪强度及与2种土工织物摩擦系数的关系。结果表明,随着含水率增加,各层土的粘聚力降低,内摩擦角减小,排水沟顶层土减小幅度较为缓慢。各层土与白色人革基布的摩擦系数随着含水率增加而降低,排水沟底层土在含水率小于10%时降低缓慢,超过10%时才大幅度降低;各层土与黑色丙纶无纺布的摩擦系数随着含水率增加开始是降低的,含水率超过10%时会有小幅度上升,但总体仍是降低的。

In order to study the influence of water content on the strength of farmland drainage ditch slope soil, five soil samples with different water contents in the top-level, middle-level and bottom of slope are selected respectively to conduct the triaxial shearing tests under unconsolidated-undrained condition and the friction coefficients between these soils and two kinds of geotextile. The experimental data indicate that： （a） the soil cohesive forces decrease gradually and the soil internal frictional angles decrease linearly with the increasing of soil water content, while the reduction of top-level soil is less than others; （b） the friction coefficients with white leather geotextile decreases gradually with the increasing of soil water content, in which, that decreases slowly for bottom soil with a water content less than 10% and rapidly for bottom soil with a water content greater than 10% ; and （c） the friction coefficients with black polypropylene non-woven fabrics decreases firstly and then increases slightly when the water content is more than 10%, but the general trend is gradually decrease.