Background Huolinhe Opencast Coal Industry Co., Ltd., piled up the wastes from coal mining in the open air, forming many giant artificial loose piles. The hills in the site are relatively steep and without any protective measures. Due to water erosion, a large number of eroded trenches are formed on the surface of the slope, and the vegetation growth is poor, which is very prone to landslide hazards. The soil erosion problem of the dump in this area has seriously affected the normal production of the mine, and caused the mine to suffer huge economic losses.
Methods In this study, jute fiber slope protection was used to control the water erosion of the dump slope in the coal mine area, and water erosion protection effects of different types and specifications of jute fiber slope protection on different parts of slope were compared. Wooden piles were set up in the upper, middle and lower parts of the test area respectively. The height of wooden piles was measured 3 months, 15 months and 27 months after the slope protection was set up. The degree of water erosion on the slope was judged according to the numerical value.
Results 1) The first year, jute fiber slope protection significantly inhibited the soil erosion depth on the slope surface and the slope gullies. The soil erosion depth on the slope gullies and slope in jute fiber slope protection area reduced by 42.08% and 30.71% respectively compared with the control. 2) The interception trough formed by jute fiber slope protection effectively stored water and soil materials, and the soil sedimentation thickness in the interception trough from top to bottom along the slope showed a linear increasing trend. 3) Both sack and sackcloth slope protection effectively inhibited water erosion on the slope surface. Compared with the control, the depth of soil erosion on the gullies and slopes with sack slope protection and sackcloth slope protection reduced by 16.39%, 51.64%, and, 48.30%, 38.10%, respectively. 4) 4, 8 and 10 m sackcloth slope protection effect was different, the erosion depth in the gully reduced by 51.64%, 51.91% and 48.36% respectively compared with the control, the erosion depth on the slope reduced by 38.10%, 43.54% and 16.33% respectively compared with the control. 5) During the 2-3 years monitoring period, there was no significant change in soil erosion depths inside the gullies and slope surfaces with 4 and 8 m specification of the sackcloth. There was remarkable soil erosion on the protected areas with 10 m specification of the sackcloth, and the average erosion depth in the gullies and slope surfaces increased by 53.13% and 34.03% until 3rd year compared to the control.
Conclusions Based on the difficulty of construction and the cost of materials, it is recommended to use 4-8 m specification with sackcloth to protect the side slope of the dump in the practice of water erosion protection. This study provides a theoretical basis for the slope water and soil erosion protection technology in the mining area.
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