# Experimental Study on the Permeability of Ecological Slopes under Rainfall Infiltration Conditions
## 4 Conclusions  
In this paper, a series of artificial rainfall experiments are conducted on four kinds of overburden slopes to study the permeability of shallow soil and the water migration law of rainwater in the slopes with different vegetation. The following conclusions can be drawn from this study:  
(1) The response time of water content monitoring points with the same buried depth and different locations is different. The closer the distance of the monitoring points to the slope surface is, the shorter the response time is. Some water content monitoring points far away from the slope only begin to respond after the end of rainfall, indicating that the infiltration rate of rainwater in the slopes is different. (2) The infiltration rate of each overburden slope shows the law from fast to slow in turn: _Magnolia multiiflora_ overburden slope, artificial slope without vegetation, _Cynodon dactylon_ overburden slope, and _Cynodon dactylon_ and _Magnolia multiiflora_ mixed slope, indicating that the initial rainfall falling on the _Magnolia multiiflora_ overburden slope is easier to infiltrate. (3) In the early stage of rainfall, the permeability coefficient of the _Magnolia multiiflora_ overburden slope is the largest. As the rainfall continues, the permeability coefficient of the artificial slope without vegetation becomes the largest, followed by that of the _Magnolia multiiflora_ overburden slope. This indicates that in the early stage of rainfall, the straight root vegetation can increase the permeability coefficient of shallow soil, but in the later stage of the test, the root system of _Magnolia multiiflora_ vegetation has no obvious effect on increasing the permeability coefficient of shallow soil. (4) The permeability coefficient of _Cynodon dactylon_ overburden slope is larger than that of _Cynodon dactylon_ and _Magnolia multilora_ mixed slope, but the overall fluctuation range of the two slopes is not as large as that of the artificial slope without vegetation and _Magnolia multiiflora_ overburden slope. The phenomena reveal that fibrous root system vegetation can reduce the permeability coefficient of shallow soil to a certain extent, whereas the mixed planting of straight root vegetation and fibrous root vegetation has the best reduction effect on the permeability coefficient of shallow soil of slopes. Conceptualization, C.Z., Z.Y. and W.W.; methodology, C.Z. and Z.Y. ; Software, C.Z., Z.Y. and W.W.; validation, C.Z. and Z.Y. ; formal analysis, C.Z., Z.Y. and W.W.; investigation, C.Z., Z.Y. and W.W.; resources, Z.Y. and W.W.; data curation, C.Z. and Z.Y. ; writing-original draft preparation, C.Z. and Z.Y. ; writing-review and editing, W.W.; visualization, C.Z., Z.Y. and W.W.; supervision, Z.Y. and W.W.; project administration, Z.Y. and W.W.; funding acquisition, W.W. All authors have read and agreed to the published version of the manuscript. **Funding:** This research is supported by the National Natural Science Foundation of China (Grant Nos. 52178371, 52108355, 52178321), the Outstanding Youth Project of Natural Science Foundation of Zhejiang Province (Grant No. LR21E080005). The China Postdoctoral Science Foundation Funded Project (Grant No. 2020M673093, 2022M712964), the Research Project of Engineering Research Centre of Rock-Soil Drilling & Excavation and Protection, Ministry of Education (Grant No. 202305), the Exploring Youth Project of Zhejiang Natural Science Foundation (LQ22E080010), the Zhejiang Province's 2022 Key R&D Plan Project-'Lingyan' Project (2022C03151), the Science and Technology Project of Zhejiang Provincial Communication Department (202305-2), and the Construction Research Founds of Department of Housing and Urban-Rural Development of Zhejiang Province (Grant No. 2021K256) are also acknowledged. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** All the data used in this research are easily accessible by downloading the various documents appropriately cited in the paper.