降雨时长对土壤结皮发育性能的影响研究

室外土遗址经常因遭遇降雨、水淹等发生结皮,造成土遗址表层性能改变,影响土遗址的进一步保护。以定量纯净黄土在等降雨大小下,通过控制不同降雨时长,试验了不同降雨时长下土壤结皮发育的过程,分别测试了降雨前后的结皮厚度、密度、硬度及孔隙结构。结果表明,在降雨量未达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度迅速增大,表皮土壤颗粒被击碎,孔隙迅速减小;在降雨量达到饱和状态时,随降雨量增大,结皮层的厚度、密度、硬度缓慢增大,但表皮土壤裂缝迅速发育,由周围向中心形成同心圆状或辐射状裂隙。研究结论可为室外土遗址的保护提供参考。

Effect of rainfall duration on the properties of the soil crust

Outdoor earthen sites often suffer from rainfall and floods, which leads to the formation of soil crust and changes in the physical properties of the surface soil. This process impacts the protection of the earthen sites. We used pure loess as a raw material and controlled the intensity of rainfall. By varying the length of the precipitation, we studied soil crusting under various precipitation times. We found that thickness, density and hardness of the soil crust increase rapidly with an increase of rainfall duration when the soil surface is not saturated; however, those properties increase more slowly with the increase of rainfall duration once the surface reaches saturation. At this stage, cracks quickly appear on the surface soil and form marks like concentric circles. The conclusions reached by this study may provide references for the protection of other outdoor earthen sites.