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盾构隧道施工引起地表沉降的传统计算方法已较为成熟,但为了合理描述盾构隧道施工引起地表沉降的多种不确定性,应同时考虑随机和模糊两种因素所带来的影响。基于Peck算式,并考虑影响地表沉降因素的随机性和模糊性,利用一次二阶矩法建立隧道施工引起地表沉降的可靠度算式,并针对工程实例,对盾构隧道地表沉降模糊随机可靠度进行计算分析。计算结果表明:对于同一允许最大沉降量,在不考虑变量随机性和模糊性的情况下,中心点法计算得到的可靠指标较验算点法偏大;随着允许沉降量的递增,中心点法和验算点法计算所得的可靠指标均呈现增大趋势,这与工程实际是一致的;而考虑随机性和模糊性因素影响的验算点法所得可靠指标呈下降趋势。通过与传统随机可靠度计算结果进行对比,得到了更为合理的结果。
The traditional calculation methods of surface subsidence caused by shield tunneling are relatively mature. However, in order to describe the various uncertainties of surface subsidence caused by shield tunneling, the influence of both randomness and ambiguity should be considered simultaneously. Based on the Peck formula and considering the randomness and fuzziness of the factors influencing surface subsidence, a second order moment method was used to establish the reliability formula of surface subsidence caused by tunnel construction. According to the engineering example, the fuzzy random reliability of the surface subsidence of the shield tunnel Calculation. The calculation results show that for the same maximum allowable settlement, the reliability index calculated by the central point method is larger than the check point method without considering the randomness and fuzziness of the variables. With the allowable settlement increasing, the center point method And the reliability index calculated by the checking point method all showed an increasing tendency, which is consistent with the actual project; while the reliability index obtained by the checking point method considering the influence of randomness and fuzziness factor shows a downward trend. By comparing with the traditional random reliability calculation results, more reasonable results are obtained.