基于离散事件模拟沥青路面施工对环境的影响

为了降低沥青路面施工过程中能耗及温室气体和污染物排放, 建立了基于离散事件模拟的沥青路面施工环境影响计算模型, 利用概率分布函数和逻辑语句将施工步骤抽象化, 应用图形化离散事件模拟软件构建了沥青路面施工离散事件模型, 将Nonroad计算模型植入, 进行了不同温室气体和污染物的动态计算, 并对比了不同施工情况的模拟排放结果。分析结果表明: 运料车将沥青混合料运输至摊铺现场的过程为沥青路面施工的主要能耗源, 为总能耗的44%, 摊铺过程与运料车返回过程的能源消耗分别为总能耗的32%、12%;温室气体与污染物排放的主要施工步骤为运输和摊铺过程, 占排放总量的50%以上; 摊铺与压实过程产生的排放物主要为NO_x, 运输过程产生的排放物主要为CO₂; 对施工工艺进行调整, 使用不间断摊铺施工会明显减少NO_x的排放, 减排量约为15%;在施工设备方面, 适当增大摊铺设备的容量会减少CO₂和HC的排放, 前者减排量约为25%, 后者约为17%。可见, 基于离散事件模拟沥青路面施工环境影响计算模型, 可量化沥青路面施工过程的能耗及温室气体和污染物排放, 优化沥青路面施工技术方案。

Environmental impact of asphalt pavement construction based on discrete event simulation

To lower energy consumption, greenhouse gases (GHGs) production, and pollutant emission in the asphalt pavement construction process, a calculation model of the environmental impact of asphalt pavement construction, based on discrete event simulation (DES), was established. The construction steps were abstracted by using the probability distribution function and a logical statement. The discrete event model of asphalt pavement construction was built by using agraphical DES software. The Nonroad calculation model was implemented to perform the dynamic calculation of the amount of different GHGs and pollutants, and the simulation emission results of different construction conditions were compared. Analysis result shows that the transportation of asphalt mixture to the paving site by trucks is the main energy consumption source in the asphalt pavement construction process, accounting for 44% of the total energy consumption. The energy consumption of the paving and truck-returning processes respectively account for 32%and 12% of the total energy consumption. The primary construction steps that lead to the emission of GHGs and pollutants are the transportation and paving processes, accounting for more than 50% of the total emissions. NO_x and CO₂ are the main emissions in the paving and compaction processes, and the transportation process, respectively. To optimize construction technology, the application of continuous paving construction can remarkably reduce the emissions of NO_x by approximately 15%. Considering construction equipment, an appropriate increase in the capacity of paving equipment can reduce the emissions of CO₂ and HC by approximately 25%and 17%, respectively. This shows that the developed environmental impact calculation model of asphalt pavement construction based on DES can quantify the energy consumptions and emissions of GHGs and air pollutants of asphalt pavement construction, and optimize the construction scheme.