基于因子分析的地铁盾构施工沉降风险辨识

Risk Identification of Ground Settlement in Subway Shield Tunneling Construction Based on Factor Analysis

根据地铁盾构施工特点,从盾构始发与到达阶段、盾构正常掘进阶段和特殊节点工程三个方面对地铁盾构施工工作过程进行结构分解,建立WBS工作分解树.从人、机、料、法、环对地铁盾构施工沉降风险进行分解,建立RBS风险分解树.通过WBS-RBS矩阵,全面辨识出38个影响地铁盾构施工沉降风险因素.对风险因素进行问卷调查及信度检验,结果显示调查样本的Cronbach’Alpha值均大于0.7,每个一级指标下的所属项目与量表总计相关值均大于0.2,量表数据可信.采用因子分析法对指标的相关性进行KMO和Bartlett球形检验,结果显示指标具有很强的相关性.采用SPSS18.0软件进行主成分分析,识别和提取出地铁盾构施工地表沉降风险16大关键因子,使指标数量大为减少,指标之间的相关性得以降低.

On the basis of characteristic of subway shield tunneling construction,work breakdown structure is carried out in subway shield construction from three main stages of shield launching and shield break-through,shield regular excavation,and special node engineering to generate the WBS tree.Risk breakdown structure is carried out from four aspects of ＂ Manpower-Management＂, ＂Machine＂, ＂ Materials＂, ＂ Method＂ and ＂ Environment＂ to generate RBS tree.Basecd on WBS-RBS,38 risk factors are identified absolutely for questionnaire surveys and reliability tests.The results show that Cronbach＇Alpha values of the samples are more than 0.7,and the total correlation values of the items in each level are more than 0.2.It reveals that the data of the questionnaire is reliable.Furthermore,the Kasier-Meyer-Olkin measure and Bartlett＇s spherical test are carried out with factor analysis to checkout the correlation of indexes.The results show that the index has a strong correlation.By using SPSS18.0software with principal component analysis,16 key factors are extracted to reduce the number of indexes and the correlation.