土体参数不确定性对软土隧洞掌子面稳定影响分析

Analysis of Variability of Soil Parameters in Soft Soil Tunnel Face Stability

岩土体参数取值对于工程设计意义较大,为更好地评估土体参数不确定性对软土隧洞掌子面稳定的影响,采用Monte-Carlo随机模拟方法,分析了土体参数变异性及样本容量水平对掌子面稳定特性的影响,提出了掌子面设计安全系数的确定方法。结合工程实例评估了设计安全系数的合理性,分析结果表明,样本容量较大时,土体参数的不确定性对软土隧洞掌子面稳定特性影响较小;小样本条件下,土体参数不确定性影响随着样本容量的降低逐渐增大。研究成果可为临时性的隧洞掌子面支护设计提供依据。

Reasonable value of geotechnical parameters has a significant influence on engineering design.In order to evaluate the influence of soil parameter uncertainty to tunnel face stability,Monte-Carlo random simulation is used to analyze the influence of the variability of soil parameters and sample capacity level to the tunnel face stability,the reasonable safety factor of soil tunnel face stability is determined.The rationality of the design safety factor is evaluated through engineering example.According to the results,the uncertainty of the soil parameters has little effect on the stability characteristics of the tunnel face when the sample capacity is large.If the sample capacity is small,the influence of variability of soil parameters increases when the sample capacity decrease.It provides a basis for the support design of the temporary tunnel face.