不同开挖坡比下埋地管道施工安全系数计算

Calculation of Construction Safety Factor of Buried Pipeline Under Different Excavation Slope Ratio

埋地管道施工中安全性影响因素复杂,现有计算方法没有考虑埋地管道地层的强度指标,导致分析结果精度较低。为此,提出基于有限元强度折减法原理的埋地管道施工安全系数计算方法。根据有限元强度折减法获取埋地管道地层的强度指标,利用大型有限元分析软件Ansys作为埋地管道施工安全系数计算的本构模型,通过不断折减地层的黏聚力和内摩擦角两项指标,计算埋地管道施工安全系数。实例分析结果表明,所提方法可有效计算施工安全系数,开挖坡比越大,施工安全系数越小,且不同开挖坡比的安全系数变化差别显著;同一开挖坡比下,各级开挖深度对埋地管道施工安全系数的影响幅度小于开挖坡比,不同开挖时步下及时采取支护措施可降低水平位移,可提升施工安全系数,增强施工稳定性。

The safety factors in the construction of buried pipelines are complex,and the existing calculation methods do not consider the strength index of the buried pipeline stratum,resulting in low accuracy of the analysis results.For this reason,a calculation method for the safety factor of buried pipeline construction based on the principle of finite element strength reduction method is proposed.According to the finite element strength reduction method,the strength index of underground pipeline stratum is obtained,and the large-scale finite element analysis software Ansys is used as the constitutive model for calculating the construction safety factor of buried pipeline.The construction safety factor of buried pipeline is calculated by continuously reducing the cohesion and internal friction angle of the stratum.The results show that the proposed method can effectively calculate the construction safety factor.The larger the excavation slope ratio is,the smaller the construction safety factor is,the change of safety factor of different excavation slope ratio is significant;under the same excavation slope ratio,the influence range of excavation depth on the construction safety factor of buried pipeline is less than that of excavation slope ratio,and timely support measures under different excavation steps can reduce horizontal displacement,improve the construction safety factor,enhance the construction stability.