喀斯特地区块石出露坡面入渗特征

为探明喀斯特地区不同块石出露坡面土壤入渗对降雨的响应特征,通过野外人工模拟降雨试验,研究喀斯特坡面4种块石出露条件和5种雨强对入渗的影响。结果表明:(1)在雨强一定的情况下,除在雨强为30 mm/h时块石裸露率的大小对坡面入渗无明显影响,在其余较大雨强下,块石裸露率为5.4%对入渗影响较小,块石裸露率为13.1%抑制入渗,块石裸露率为42.9%促进入渗,在降雨前期,块石的存在对入渗均有促进作用。(2)在块石裸露率及降雨量一定的情况下,随着雨强的增大,坡面的入渗量呈明显下降趋势,而平均入渗速率整体呈现先增大后减小随后又增大的趋势;在降雨前期,随着雨强的增加,入渗量呈先减少后增加的波动性变化,前期入渗率随着雨强的增大而增加,拐点均出现在雨强为90 mm/h。(3)在对入渗过程进行模拟后发现,方正三公式在有块石出露坡面上的的拟合效果比Kostiakov公式的拟合效果更好。

Infiltration Characteristics of Boulder Outcropping Slope in Karst Area

In order to investigate the response characteristics of soil infiltration on different boulder outcropping slopes to rainfall in karst area,the influence of four boulder outcropping conditions and five rain intensities on infiltration was studied. Field artificial rainfall simulation method was adopted. The results showed that: (1) When the rainfall intensity was 30 mm/h,the size of the boulder outcropping rate had no significant effect on infiltration. However,in the other rainfall intensities,the rate of boulder outcropping was 5.4%,which had little effect on infiltration; while the rate of boulder outcropping was 13.1%,which inhibited infiltration,and the rate of boulder outcropping was 42.9%,which promoted infiltration. In the early period of rainfall,the existence of boulder could promote the infiltration. (2) When the boulder outcropping rate and rainfall remained unchanged,the stronger the rain,the less the infiltration. While the average infiltration rate increased first,then decreased and then increased again. In the early period of rainfall,with the increases of rainfall intensities,the infiltration volume decreased first and then increased. And the early infiltration rate increased with the increases of rain intensities. In both cases,the inflection point occurred when the rain intensity was 90 mm/h. (3) After simulating the infiltration process,it was found that universal empirical model showed better fitting effect than Kostiakov model on the boulder outcropping slope.