地裂缝错动对地铁区间隧道影响的三维离散元分析

拟建西安地铁2号线穿越10条地裂缝,地裂缝活动将影响地铁2号线的安全运营。应用三维离散元程序3DEC建立三维计算模型,分析了裂缝带错动对地铁区间隧道盾构管线的影响,得出了不同错距工况下隧道衬砌的变形和应力。通过计算得知,当土体上下盘底部竖向错距由10cm增大到93cm时,引起的衬砌竖向变形量由0. 712cm增大到13. 99cm,且最大变形均发生在沿纵向约35～36m处,距裂缝带距离约为9. 5～8. 5m;引起的管道纵向最大拉应力则由0. 65MPa增大到18. 43MPa,最大压应力由0. 611MPa增大到16. 9MPa,且最大应力区与最大变形区一致。这一结论的获得可为地铁设计、施工及其安全运营提供科学的理论指导及设计依据。

THREE-DIMENSIONAL DISTINCT ELEMENT ANALYSIS OF GROUND FISSURE DISLOCATIONS ON SHIELD PIPELINES OF OPERATIONAL TUNNELS ALONG XI'AN SECOND SUBWAY LINE

The second subway line in Xi'an city crosses 10 ground fissures,and these ground fissures will influence the safety of subway line.Using the three-dimensional(3D) distinct element code(3DEC),a computational model is built.The effect of ground fissure dislocation on the shield pipeline of running tunnel of subway is examined.The deformations and stresses under different dislocations of tunnel lining is obtained.The calculated results show that,If the dislocation is changed from 10 to 93 cm,the deformation will be changed from 0.712 to 13.99 cm,and the maximum deformation will occur at 35 to 36 m along longitudinal direction about 9.5 to 8.5 m distance to ground fissures.The maximum tensile stress will be changed from 0.65 to 18.43 Mpa,and the maximum compression stress will be changed from 0.611 to 16.9 MPa.The maximum deformation and stress zones are uniform.The findings can provide effective design parameters and scientific evidences for quantify the effect of ground fissures dislocation on running tunnel of subway.