红壤区崩岗侵蚀的土壤特性与影响因素研究

Research on the soil characteristics and factors of collapsing erosion in the red soil zone

针对南方崩岗的发育与重力侵蚀密不可分的特点,利用野外采样和室内分析的方法,对南方第四纪红土、花岗岩、红砂岩发育形成的典型红壤的岩土力学性质、物理性质和颗粒组成进行了分析研究,探讨了崩岗侵蚀的土壤特性与影响因素。结果表明:(1)崩岗侵蚀与土壤的岩土力学性质有着密切的联系。第四纪红土、红砂岩、花岗岩土壤的抗剪强度依次降低、压缩性依次增大的规律与其崩岗侵蚀规模依次增大的现象相一致。(2)崩岗侵蚀与土壤的物理性质密切相关。花岗岩、红砂岩地区土壤稳定入渗率大有利于崩岗的发育,红砂岩地区崩岗集中在沟头分布的特征与其低液塑限性质有关。(3)土壤颗粒组成是影响崩岗发育的根本性物质因素。

In light of the inseparable features between collapsing erosion and gravity erosion in the red soil zone of South China, this paper seeks to a comparative analysis of soil rocksoil mechanical property, phys ical property and particlesize composition for the typical Quaternary red earth, granite and red sandstone by using the methods of field sampling and laboratory analysis. The results demonstrate that （a） collapsing erosion is closely related to the soil geotechnical property, and the antishearing strength decreases in se quence of Quaternary red earth, red sandstone and granite area, while the compressibility presents the op posite trend in those three areas, leading to the upward trend in the size of collapsing erosion; （b） collaps ing erosion is closely related to the soil physical property, and high soil steady infiltration rate is benefi cial to the development of collapsing erosion in granite and red sandstone area, and characteristics of col lapse erosion distribution concentrated in gully head in red sandstone area strongly link to low liquidplas tic limit; and （c） particlesize composition is a fundamental material factor affecting the growth of collapse erosion.