Grassland ecosystems, as the basic natural resources in the Inner Mongolia Autonomous Region, are becoming increasingly sensitive to human intervention, leading to deterioration in fragile ecosystems. The goal of this study was to describe the restoration policy-oriented adoptive changes to basic household consumption patterns of food, fuel, and water, and their spatial distribution by grassland types in the region. Basic household consumption data were collected in the meadow steppe (Hulun Buir), typical steppe (Xilin Gol), and semi-desert steppe (Ordos) ecosystems using structured questionnaires administered to 209 herders and farmers. In 2010, the householders’ intake comprised a low amount of agri-crops, including staple foods, vegetables and fruit with a high amount of meat, which still dominated the patterns of food consumption. However, the number of households preferring this pattern is decreasing and higher amounts of agri-crop and lower amounts of meat consumption pattern is increasing. From 1995 to 2010, fuel consumption patterns changed from being dominated by bio-fuels (dung) to being dominated mainly by electricity and gas. However, bio-fuel remains a major energy source for daily life in the meadow steppe ecosystem. In all three surveyed grassland types, the use of coal, electricity and gas increased from 1995 to 2010. The source of domestic water in all three surveyed areas is from groundwater, with an increasing trend to use tap water from a public supply rather than from privately owned wells.

To study the influence of wetting‐drying cycles on dynamic mechanical properties of rock masses, the impact compression tests of red sandstone samples were carried out by using a split Hopkinson pressure bar (SHPB) apparatus with a diameter of 50 mm. The results showed that under the same number of wetting‐drying cycles, the dynamic compressive strength of red sandstone increased exponentially with the strain rate, and the sensitivity of the strain rate decreased with the increase of wetting‐drying cycles. The deterioration effect of wetting‐drying cycles was significant, and the dynamic and static compressive strength decreased with the increase of wetting‐drying cycles; the higher the strain rate, the stronger the sensitivity to wetting‐drying cycles. Besides, the influence of wetting‐drying cycles and strain rate was comprehensively studied, and the equation of dynamic compressive strength of red sandstone was obtained. After different wetting‐drying cycles, the fractal characteristics of red sandstone dynamic fragmentation were obvious, and the fractal dimension was 2.02–2.80, and the fractal dimension increased logarithmically with the strain rate. Finally, the internal microstructure of red sandstone after different wetting‐drying cycles was analyzed, and the degradation mechanism of the rock by the cycles was discussed.

Fly ash cement is used to solidify marine clay to prepare marine-clay-based cemented paste backfill (MCCPB) to fill the underground goaf of mines, which not only utilizes solid waste such as fly ash and marine clay, but also controls surface subsidence and protects the environment. To simulate the complex underground mine water environment of the filling body, a dry-wet cycle aquatic environment test under different material ratios and curing ages was designed. The water absorption and unconfined compression strength (UCS) of MCCPB with curing ages of 7 and 28 days under the action of 0, 1, 3, and 7 dry-wet cycles were investigated. The results indicate as the number of dry-wet cycles increases, the surface of MCCPB becomes significantly rougher, and the water content and the solid mass decrease accordingly. Different ratios and curing ages of MCCPB in dry-wet cycles of the UCS tend first to increase, then decrease. Meanwhile, the stress-strain curve of the specimen shows that the trend in the elastic modulus is consistent with that of UCS (first increasing, then decreasing), and that, the minimum UCS value of the specimen still meets the early strength requirements of cemented paste backfill in coal mine geothermal utilization. On the one hand, it proves the feasibility of fly ash cement-solidified marine clay for use as cemented paste backfill in coal mines; on the other hand, it also expands the available range of cemented paste backfill materials in coal mines.

In this paper, the slit Hopkinson pressure bar (SHPB) experiments were conducted to investigate the dynamic mechanical characteristics of red sandstone during acid dry-wet cycles. The appearance of the samples was evaluated using scanning electron microscopy, and the process of red sandstone degradation under acid dry-wet cycles was examined. The results reveal that, as compared to neutral solution, acid solution enhances the degree of degradation induced by dry-wet cycles in red sandstone. The dynamic compressive strength and elastic modulus of red sandstone steadily decline as the number of dry-wet cycles increases, and the lower the pH of solution, the greater the reduction. The mechanism of degradation of red sandstone during acid dry-wet cycles may be explained in two ways. First, the chemical interaction between the mineral components in the sample, such as cement and feldspar, and H⁺ in the acid solution has accelerated the formation of secondary pores and fractures, resulting in a decrease in the cementation capacity between mineral particles. Second, partial breakdown of the major mineral particles softens the mineral skeleton.