中文摘要：

为实现桩基础施工阶段环境影响的客观评价，优选施工工艺，基于施工阶段环境表现分析系统（Construction Environmental Performarlee Analysis System，CEPAS）定量评价了施工中常见的人工挖孔灌注桩和长螺旋钻孔管内泵压CFG桩的环境影响，同时分析了环境影响指标和施工工艺。结果表明，1m^3人工挖孔灌注桩的社会支付意愿值（178．94元）大于长螺旋钻孔管内泵压CFG桩（25．43元），因此，为提高桩基础的绿色施工水平，可以优先采用长螺旋钻孔管内泵压CFG桩。对人工挖孔灌注桩各工序的环境影响分析表明，钢筋加工和混凝土生产工序占总社会支付意愿值的比例最大（99．50％）；对长螺旋钻孔管内泵压CFG桩，混合料制备占总社会支付意愿值的比例（89．46％）大于其他工序。因此，改进这些主要环境影响工艺能更有效地降低这两种桩的环境影响。

英文摘要：

The present paper takes it as its interest to make a study of the environmental impact of the pile foundation construction. For this research purpose, we have chosen some environment-friendly construction plans based on CEPAS （Construction Environmental Performance Analysis System）. In order to assure the objectivity of our assessment, two kinds of commonly used pile foundations were chosen, the manually excavated pile and CFG pile with long tube pump pressure so that it is easier to find the environmental impact of pile foundation construction and the environmental impacts resulting in the values of WTP （Willingness-to-pay） of 1 m^3 pile foundation. Next, a comparative analysis of environmental impact indexes and construction process was made to improve the environmental performance of pile foundation. The results of our analysis show that the value of WTP of 1 m^3 of manually excavated pile （178.94 yuan） tends to be much greater than CFG pile with long tube pump pressure （25.43 yuan）, which indicates CFG pile with long tube pump pressure proves to be more optimal for promoting green construction. As to the manually excavated pile, further analysis has been done over the distribution of the environment impacts among the unit processes, which reveals that the steel processing and the concrete manufacture contribute together to the greatest portion （99.50%） of WTP. However, for CFG pile with long tube pump pressure, it was found that the compound preparation has much higher environmental impact as compared with any other unit processes, which may account for 89.46 % of WTP. It can be concluded that it would be more effective to stress these processes to improve the environmental performance for the two pile foundations.