马永峰 周丁恒 李凤岭 黄赫

摘 要：沿海地区钻孔灌注桩易发生缩孔、塌孔现象，正确地对钻孔灌注桩孔壁行稳定性进行分析与评价，对地基处理效果具有重要影响。首先，对钻孔灌注桩孔壁稳定性有关的参数进行了分类，建立了指标相互独立的钻孔灌注桩塌孔风险指标体系，并应用模糊理论建立了钻孔灌注桩塌孔风险评价模型；其次，基于钻孔灌注桩专家系统对风险指标体系中各指标的评估，得出了各指标的权重，并将风险指标划分为3个级别，建立了分级标准后，提出了钻孔灌注桩施工是孔壁稳定性等级的划分方法；最后，基于MATLAB软件编制了灌注桩塌孔风险评价和等级分区的计算评价软件。工程应用实例表明建立的钻孔灌注桩塌孔风险指标体系和风险评价模型可应用于评估钻孔灌注桩施工时孔壁稳定性等级。

关键词：钻孔灌注桩；模糊理论；风险指标体系；风险评价模型

中图分類号： TU443 文献标志码：A

文章编号：1672-1098（2017）05-0018-07

Abstract：For bored pile in coastal area， shrinkage and collapse tend to occur easily. Analysis and evaluation of hole-wall stability has an important influence on foundation treatment effect. Firstly， parameters and indexes related to the hole-wall stability of bored pile were classified and the index system for evaluating the risk of bored pile collapse was established. The model for evaluating the collapse risk of bored pile was established by using the fuzzy clustering identification theory. Then， the weights of the indexes affecting the hole-wall stability of bored pile were determined by experts， grading the risk indexes with three levels. The method for classifying the stability grades of bored pile and corresponding standard were proposed accordingly. Finally， software of risk collapse assessment and degree division was programmed. The application indicated that the proposed model and index system were feasible in assessing the grades of hole-wall stability in the construction of bored pile.

Key words：bored pile；fuzzy theory；risk index system；risk evaluation model

沿海地区地质条件较差，多为软土底层，钻孔灌注桩钻孔时，孔壁状态不稳定，易发生缩孔、塌孔的现象，会造成资源浪费和环境问题[1-3]3 281-3 284，所以研究钻孔灌注桩孔壁稳定性具有重要的经济价值和社会效益。影响软土地区钻孔灌注桩孔壁稳定性因素有地质条件、泥浆重度、孔隙水压力、孔径、孔深和施工方法等，钻孔灌注桩孔壁坍塌风险因素具有多样性、复杂性及不确定性特点[4-9]86-88，难以直接定量判定，而模糊数学方法[10-11]可针对这些特点处理不确定信息，从而定量分析各风险因素对孔壁稳定性影响的程度。……