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利用FLAC3D有限元模拟软件,模拟在既有地铁荷载下进行北京直径线开挖。结合实测结果,研究了隧道周边管线的位移、应力及地表沉降。结合相关管线安全性评价标准,对地下管线的安全性进行分析预测。结果表明,管线水平及倾斜变形均在标准控制范围内。利用地表沉降预测管线安全性时,发现地表沉降最大值、地表最大斜率、地表损失系数及地层移动坡角值均小于控制值。但管线的部分区域最大主拉应力集中于1.6～1.72 MPa范围内,略大于混凝土抗拉强度1.43 MPa。为了保证管线的正常使用,需对管线周围土体进行加固。
FLAC3D finite element simulation software was used to simulate the excavation of Beijing Diameter Line under the existing subway load. Combined with the measured results, the displacement, stress and surface settlement of the surrounding pipelines are studied. Combined with the relevant pipeline safety evaluation criteria, the safety of underground pipeline is analyzed and predicted. The results show that the pipeline level and tilt deformation are within the standard control. When using surface subsidence to predict pipeline safety, it is found that the maximum value of surface subsidence, the maximum slope of the earth’s surface, the coefficient of surface loss and the slope value of formation movement are all less than the control values. However, the maximum principal tensile stress in some areas of the pipeline is concentrated in the range of 1.6 to 1.72 MPa, slightly larger than the tensile strength of concrete of 1.43 MPa. In order to ensure the normal use of the pipeline, the soil around the pipeline needs to be reinforced.