淺埋大斷面黃土隧道初期支護安全性分析
發(fā)布時間：2018-11-25 22:18
【摘要】：以大西客運專線忻州隧道三七微臺階法開挖為工程背景,采用FLAC3D模擬分析施工過程中初期支護結(jié)構(gòu)的受力特性,并與錨桿軸力和噴射混凝土應力的現(xiàn)場測試結(jié)果進行對比分析,最后結(jié)合型鋼混凝土截面受力計算方法,評價型鋼混凝土初期支護結(jié)構(gòu)的安全性。研究結(jié)果表明:1型鋼混凝土主要承受壓應力,且沿隧道中線呈軸對稱分布,最大壓應力出現(xiàn)在拱腰位置,而拱腳處局部承受拉應力,為施工中的薄弱部位,噴射混凝土應力實測值相對計算值偏小,但分布規(guī)律與計算值吻合性較好;2隧道系統(tǒng)錨桿主要承受拉力作用,最大拉力在錨桿1 m位置,沿隧道輪廓從拱頂?shù)焦澳_遞減,且計算值略大于實測值,兩者分布規(guī)律一致;3型鋼混凝土結(jié)構(gòu)安全系數(shù)從隧道拱頂?shù)焦澳_依次遞增,且同一部位軸力安全系數(shù)小于彎矩安全系數(shù),軸力安全系數(shù)最小值為3.86,滿足規(guī)范要求,可適當增大鋼拱架支護間距或減小噴射混凝土強度。
[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.
【作者單位】： 同濟大學道路與交通工程教育部重點實驗室;中鐵二十五局集團第五工程有限公司;浙江省交通規(guī)劃設(shè)計研究院;
【分類號】：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.
【作者單位】： 同濟大學道路與交通工程教育部重點實驗室;中鐵二十五局集團第五工程有限公司;浙江省交通規(guī)劃設(shè)計研究院;
【分類號】：U455.7
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