浅埋大断面黄土隧道初期支护安全性分析
发布时间：2018-11-25 22:18
【摘要】：以大西客运专线忻州隧道三七微台阶法开挖为工程背景,采用FLAC3D模拟分析施工过程中初期支护结构的受力特性,并与锚杆轴力和喷射混凝土应力的现场测试结果进行对比分析,最后结合型钢混凝土截面受力计算方法,评价型钢混凝土初期支护结构的安全性。研究结果表明:1型钢混凝土主要承受压应力,且沿隧道中线呈轴对称分布,最大压应力出现在拱腰位置,而拱脚处局部承受拉应力,为施工中的薄弱部位,喷射混凝土应力实测值相对计算值偏小,但分布规律与计算值吻合性较好;2隧道系统锚杆主要承受拉力作用,最大拉力在锚杆1 m位置,沿隧道轮廓从拱顶到拱脚递减,且计算值略大于实测值,两者分布规律一致;3型钢混凝土结构安全系数从隧道拱顶到拱脚依次递增,且同一部位轴力安全系数小于弯矩安全系数,轴力安全系数最小值为3.86,满足规范要求,可适当增大钢拱架支护间距或减小喷射混凝土强度。
[Abstract]:Taking the excavation of Xinzhou Tunnel in Daxi passenger dedicated Line as the engineering background, the mechanical characteristics of the initial supporting structure in the construction process are simulated and analyzed by FLAC3D, and the results are compared with the results of the field test of the axial force of the anchor rod and the stress of the shotcrete. Finally, the safety of the initial support structure of steel reinforced concrete is evaluated by combining with the calculation method of section stress of steel reinforced concrete (SRC). The results show that: 1 the steel reinforced concrete (SRC) is mainly subjected to compressive stress and distributes symmetrically along the middle of the tunnel. The maximum compressive stress appears in the arch, and the arch foot is the weak part of the construction. The measured stress value of shotcrete is smaller than the calculated value, but the distribution law is in good agreement with the calculated value. (2) the anchors of tunnel system mainly bear the effect of tensile force, the maximum tensile force is in the position of 1 m of the anchor rod, and the calculated value is slightly larger than the measured value along the tunnel outline from the arch top to the arch foot, and the distribution of the two is in accordance with the law of distribution; (3) the safety factor of steel reinforced concrete structure increases from the tunnel vault to the arch foot, and the safety factor of axial force in the same position is less than that of bending moment, and the minimum value of safety factor of axial force is 3.86, which meets the requirements of the specification. The support spacing of steel arch frame can be increased appropriately or the strength of shotcrete can be reduced.
【作者单位】： 同济大学道路与交通工程教育部重点实验室;中铁二十五局集团第五工程有限公司;浙江省交通规划设计研究院;
【分类号】：U455.7
[Abstract]:Taking the excavation of Xinzhou Tunnel in Daxi passenger dedicated Line as the engineering background, the mechanical characteristics of the initial supporting structure in the construction process are simulated and analyzed by FLAC3D, and the results are compared with the results of the field test of the axial force of the anchor rod and the stress of the shotcrete. Finally, the safety of the initial support structure of steel reinforced concrete is evaluated by combining with the calculation method of section stress of steel reinforced concrete (SRC). The results show that: 1 the steel reinforced concrete (SRC) is mainly subjected to compressive stress and distributes symmetrically along the middle of the tunnel. The maximum compressive stress appears in the arch, and the arch foot is the weak part of the construction. The measured stress value of shotcrete is smaller than the calculated value, but the distribution law is in good agreement with the calculated value. (2) the anchors of tunnel system mainly bear the effect of tensile force, the maximum tensile force is in the position of 1 m of the anchor rod, and the calculated value is slightly larger than the measured value along the tunnel outline from the arch top to the arch foot, and the distribution of the two is in accordance with the law of distribution; (3) the safety factor of steel reinforced concrete structure increases from the tunnel vault to the arch foot, and the safety factor of axial force in the same position is less than that of bending moment, and the minimum value of safety factor of axial force is 3.86, which meets the requirements of the specification. The support spacing of steel arch frame can be increased appropriately or the strength of shotcrete can be reduced.
【作者单位】： 同济大学道路与交通工程教育部重点实验室;中铁二十五局集团第五工程有限公司;浙江省交通规划设计研究院;
【分类号】：U455.7
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