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以南水北调中线穿黄隧洞环锚预应力混凝土衬砌结构为例,利用有限元软件ANSYS建立计算模型,通过三维有限元计算并分析了环锚预应力结构中锚索间距对衬砌结构强度和稳定性的影响及其相关规律。结果表明,当锚索间距过大时,不能满足衬砌结构的承载能力及环向应力沿轴向的均匀性要求,局部区域因环向拉应力超过混凝土抗拉强度设计值时将出现裂纹;当锚索间距过小时,衬砌结构偏于安全,但影响工程施工的便利性并提高工程造价。对于穿黄隧洞工程,锚索间距为0.4~0.6m时可满足其安全运行要求,为尽可能降低锚索的工程造价,兼顾锚索的锚固作用及工程的经济效益,建议在满足工程结构受力的要求下优先选取较大的锚索间距。
Taking the South-to-North Water Diversion Middle Route Crossing Yellow River tunnel ring anchor prestressed concrete lining structure as an example, the finite element software ANSYS was used to establish the calculation model. The three-dimensional finite element method was used to calculate and analyze the strength and stability of the anchor structure in the annular anchor prestressed structure Influence and its related laws. The results show that when the distance between anchor cables is too large, the bearing capacity of lining structure and the uniformity of hoop stress along the axial direction can not be satisfied. Cracks will occur when the circumferential tensile stress exceeds the designed value of tensile strength of concrete. When the distance between anchor cables is too small, the lining structure is biased to safety, but it will affect the convenience of construction and increase the construction cost. For the project of crossing the Yellow River tunnel, the safe operation requirements can be satisfied when the spacing of anchor cables is 0.4 ~ 0.6m. In order to reduce the construction cost of anchor cables as much as possible and balance the anchorage effect of anchor cables and the economic benefits of the project, Force requirements to give priority to choose a larger anchor spacing.