Vegetation concrete is one of the most widely used substrates for slope ecological protection in China. However, there are still some imperfections that are disadvantageous for plant growth, such as high density, low porosity, insufficient nutrient retention ability and so on. In this paper, the effect of wood activated carbon and mineral activated carbon on the physicochemical properties of vegetation concrete is studied. The experimental results show that the activated carbon proportion in vegetation concrete is positively related to the porosity, permeability coefficient, water holding capacity, and nutrient content and retention ability, while it is negatively related to the dry density, water retention ability, cohesive force and internal friction angle. However, it should be noticed that when the proportion exceeds 2%, the average height, aboveground biomass and underground biomass of Cynodon dactylon decrease with increasing proportion of activated carbon. The effect of wood activated carbon is generally more remarkable than that of mineral activated carbon. In addition, according to the research results, the effect of activated carbon on vegetation concrete can last for at least half a year, although it does slowly deteriorate with increasing time. By comprehensive consideration of the current industry standard, previous research results and economical reasoning, the recommended type of activated carbon is wood, with a corresponding suitable proportion ranging between 1 and 2%.

Many measures have been applied to quarry slopes for ecological restoration; however, the performance of these measures has not been clearly evaluated. Thus, research evaluating the effects of the ecological restoration of quarry slopes in Caidian District was carried out to quantify the performance of different ecological restoration methods, to evaluate the effect of ecological restoration projects and to learn the applicability of different restoration technologies in Caidian District. The research can provide a reference for scientific decision-making in the follow-up management of ecological environments in Caidian District. First, the ecological restoration process of quarries in Caidian District was described in detail by visiting the relevant design and construction units. Through observational analysis from the aspects of applicable slope gradient, slope flatness requirements, project cost, the vegetation coverage conditions, the species diversity conditions and construction difficulty, the advantages and disadvantages, as well as the applicability of different ecological restoration technologies were preliminarily clarified. Then, the comprehensive evaluation index system of the ecological restoration effects was established by using the fuzzy AHP method. The ecological restoration effects of each sample plot were evaluated quantitatively based on the data of the evaluation indexes obtained by the field investigation and sampling analysis. Finally, according to the evaluation results, the existing problems in the follow-up management of the ecological restoration of quarry slopes in Caidian District were analyzed, and corresponding countermeasures and suggestions were proposed. The results showed that the quantitative evaluation results obtained by the comprehensive evaluation system of ecological restoration were consistent with the observational analysis results, and the validity of the evaluation system was proven.

Vegetation‐concrete is one of the most widely used substrates in ecological slope protection engineering. The porosity of the vegetation‐concrete must be high enough to satisfy the growth needs of the plant roots, while the mechanical properties must be strong enough to satisfy the self‐stability requirement of the substrates on the slope. It is necessary to balance these two aspects in the design of vegetation‐concrete. As one of the main components in vegetation‐concrete, organic material has a remarkable effect on both the porosity and the mechanical properties of the substrate. In this paper, four types of common organic materials (rice husks, sawdust, and corn distillers’ and unhulled rice distillers’ grain) are chosen to research the effect of the organic material type and proportion on the porosity and mechanical properties of the substrate. The experimental results show that the porosity of samples containing corn distillers’ grain is clearly higher than those of the other samples types, while situation of the mechanical properties is the opposite. It can be concluded that organic material with a large grain size is not suitable for use in vegetation‐concrete directly and needs to be crushed before use to prevent crack formation. The research results also show that the rates of increase in porosity decrease with more organic material added, while the rates of decrease in the unconfined compressive strength and the elasticity modulus increase. From a comprehensive consideration of the required mechanical properties and plant growth, organic material with a small grain size is most suitable for use in vegetation‐concrete, and the suitable proportion is between 7% and 9%.

Although the influence of gradation on soil properties has been recognized, the grain sizes have not yet been fully considered in maximum dry density (MDD) evaluation and prediction. This study explores the impacts of full grain sizes on the MDD and evaluates MDDs through different particle size distribution (PSD) curves of gravelly soils. First, full grain sizes, d₁₀–d_100, were extracted from 90 gravelly soil samples and employed as input parameters to develop the neural model for MDD, by using genetic algorithm (GA) to optimize the back-propagation (BP) neural network. A mean impact value (MIV) method was then proposed to quantify the impact of each grain size, followed by the vibrating compaction tests for 22 artificially designated gravelly soil specimens to verify the model and evaluate the MDDs based on grain sizes. The model analysis and verification tests agreed with each other and clearly showed the intrinsic dependence of grain sizes on MDD for gravelly soils. As revealed by MIV analysis, d₅₀–d₁₀₀ and d₁₀–d₄₀ displayed positive and negative impact to MDD during compaction, behaving as the relatively coarse and fine grain sizes, respectively. Additionally, the relative impact weight showed that d₁₀₀ tends to have the largest impact to MDD, and high-sensitivity (HS), medium sensitivity (MS), and low sensitivity (LS) could be proposed to distinguish these grain sizes. As the MDD was found to correspond exactly to the unique soil gradation, the full grain sizes should be employed to precisely predict and correctly evaluate the MDD of gravelly soils.