黄土边坡防护工程碳排放评价体系与模型构建

Carbon emission assessment system and model construction of loess slope protection project

关键词:  黄土边坡防护工程  生命周期  CRITIC 法  碳排放评价模型

Key words:  loess slope protection engineering  life cycle  CRITIC method  carbon emission evaluation model

摘要:

近年来，边坡防护工程因产生大量的温室气体备受社会各界关注，但关于黄土边坡防护工程碳排放的相关研究鲜有报道。基于生命周期评价理论，将黄土边坡防护工程分为生产阶段、运输阶段、施工阶段与维护管理四个主要阶段，建立黄土边坡防护工程的碳排放评价体系；采用碳排放系数法对各阶段评价指标的碳排放量进行计算，使用CRITIC法对指标进行权重分析，考虑绿色植被的固碳能力，构建黄土边坡防护工程的碳排放评价模型。以具体工程为例，采用该模型对不同方案的碳排放量进行评价，结果表明：柔性支护新技术总碳排放量远小于传统支护技术，能率先达到零排放，节能减排优势明显。可为边坡防护柔性新技术的推广提供理论依据。

Abstract:

Background, aim, and scope Recently, slope protection projects have attracted much attention from all walks of life, but few reports have been devoted to carbon emissions from loess slope protection projects. By this view, this paper aims to elucidate a slope protection project in northern Shaanxi as a reference object to examine the carbon emission of the loess slope protection project through establishing a carbon emission evaluation model. Materials and methods Based on the life cycle assessment theory, the loess slope protection project can be divided into four main stages: production stage, transportation stage, construction stage, and maintenance management stage, and an appropriate carbon emission evaluation model for the loess slope protection project is established. To calculate the carbon emissions of the evaluation indicators in each stage, the carbon emission coefficient methodology is employed, and the CRITIC-based approach is adopted to examine the weights of the indicators. Considering the carbon fixation ability of green vegetation, the carbon emission evaluation model of the loess slope protection project has been established. Results Taking a specific project as an example, this model is employed to evaluate carbon emissions from various designs. The achieved results reveal that the total carbon emission of the novel flexible support technology is much lower than the traditional support technology. Compared with the traditional support technology, the new one is able to reach zero emissions earlier, whose advantages of energy saving and emission reduction are noticeable. Discussion By analyzing the carbon emissions and the weight of each evaluation index of the concrete loess slope project, it is determined that with the increase in the consumption of materials and energy with a high carbon emission coefficient, their carbon emissions occupy a very large proportion in engineering construction. However, green vegetation is worth a lot of weight because its carbon sequestration is strongly influenced by time and region. Therefore, using green materials, reducing energy consumption, and increasing the level of green vegetation effectively contribute to the reduction of carbon emissions in engineering constructions. At the same time, the carbon emission evaluation model constructed by combining the CRITIC method and the life cycle assessment theory is capable of taking into account the weight of various factors in different time periods, which can be regarded as a valuable reference for long-term carbon emission evaluation of engineering construction. Conclusions Due to the difference in material selection, quantity, and construction methods, the carbon emission ratios of various evaluation indexes in engineering construction are dissimilar; however, the carbon emissions are mostly concentrated in the production and construction stages. Additionally, green vegetation exhibits the highest weight because it contrasts with other indicators and has high volatility, so it has great benefits in reducing carbon. Recommendations and perspectives In the scheme design, carbon reduction can be effectively achieved by increasing the planting area. Further, the choice of building materials should not be overlooked. The preferential exploitation of novel low-carbon materials also leads to the reduction of the project’s carbon emissions.