Abstract:
The disintegration, erosion, and collapse of red-bed mudstone slopes in watershed gullies is prominent in the extreme climate, heightening the risk of disaster chains related to debris flows in these channels. Developing hazard chain-cutting technology in watershed gullies is of great significance for controlling the sediment supply of debris flows. This study selects Tertiary red-bed mudstone from the Xining Basin, and utilizes a self-developed testing apparatus for measuring the disintegration indexes of untreated red-bed mudstone and MICP-treated red-bed mudstone. A list of disintegration tests were conducted to explore the disintegration characteristics and protective effects of MICP-solidified red-bed mudstones under the influence of factors such as temperature, pressure, initial moisture content and curing time. The results indicate that MICP mitigates the disintegration process of red-bed mudstone, which is significantly influenced by initial water content. At low water content, the disintegration process of red-bed mudstone is considerable, which is also accelerated by higher temperatures and pressures. The pressure plays a dual role of mechanical constraint and hydraulic driving in the disintegration process of red bed mudstone. The prolongation of curing time exerts a significant inhibitory effect on the disintegration process of MICP-solidified red-bed mudstones. Specifically, for the specimens cured for 3, 7, and 14 days, the disintegration ratio at initial-stage decreases by an average of 13%, 33%, and 39%, respectively. The disintegration rate drops by an average of 13%, 27%, and 36%, respectively. This is because MICP converts particle contacts from point contact to surface contact, and a calcareous cementation crust forms on the surface of the red-bed mudstone, resulting in a notably lower disintegration ratio and rate during the intense disintegration stage. The findings offer support for ecological protection of red-bed mudstone slopes in weathered gullies of Northwest China.