干热河谷不同活跃程度冲沟沟床土体抗冲性差异

Soil Anti-scourability on Gully Beds with Different Active Degree in Dry-hot Valley Region

为探明极端气候条件下干热河谷不同活跃程度冲沟沟床的抗侵蚀性能,选取活跃冲沟、较活跃冲沟和稳定冲沟三类沟床表层土体,设置0,50%和100%3个不同初始含水率的处理,进行原状土水槽冲刷试验。结果表明,不同活跃程度冲沟沟床的土体抗冲性有所差别,其土体抗冲性在不同初始含水率条件下均表现为活跃冲沟<较活跃冲沟<稳定冲沟。初始含水率对冲沟土体抗冲性影响较大,随初始含水率的增加,三类活跃程度冲沟沟床的径流产沙量逐步降低,其土体抗冲性均表现为初始含水率0的土体抗冲性最弱,初始含水率50%的土体抗冲性次之,初始含水率为100%的土体抗冲性最强。土体容重、粘粒含量在不同初始含水率条件下均是影响三类冲沟沟床土体抗冲性的关键因子。

To study the differences in soil anti-erosion capability on gully beds with different active degree under extreme weather conditions, three different active gully beds （active gully bed, semi-active gully bed and stable gully bed） were selected to determine the soil anti-scourability（ANS） by carrying out undisturbed soil sample washing experiment, in which three soil initial water content treatments（0, 50% and 100%） were established. The results indicated that soil ANS differed among the three gully beds with different active degree, which ranked in such an order：Active gully bed〈semi-active gully bed〈stable gully bed. The initial water content showed greater influence on soil ANS than active degree of gully bed. Sediment yield on three gully beds gradually reduced with the increasing initial water content, while soil ANS listed in the following order：The initial water content of 0〈the initial water content of 50%〈the initial water content of 100%. The results of multiple regression analysis suggested that soil bulk density and clay content were the determining factors in affecting soil ANS on the three gully beds under different initial water content.