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The estimation of the design concept of large face and long distance tunnel through the three dimensional trapdoor experiments and the numerical analyses

通过三维活板门实验及数值分析对大断面长距离隧道设计理念的评价

基本信息

批准号：
10555167
负责人：
ADACHI Toshihisa
金额：
$ 5.25万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

In order to establish the design concept of extra large face and long distance tunnels in which the needs are increasing, tunnel lining modeling tests and three dimensional trapdoor experiments have been performed. Then, the bending moments and the earth pressures acting on the tunnel lining, and the mechanism of tunnel excavation have been discussed.Assuming the excavation on sandy ground in the tunnel lining modeling tests, the experiments in consideration of various overburdens and shapes of tunneling face have been carried out on both gravity and centrifuge conditions. Based on the experimental results, we have discussed some effective factors of tunnel mechanism, namely, the earth pressures and the bending moments acting on the tunnel lining, the earth pressure acting on the ground around tunnel, and the ground surface settlement. Moreover, theoretical discussions of the earth pressures acting on the tunnel lining have been performed with the aid of Terzaghi earth pressure theory. … More In consequence, 1) with the shape of tunnel face being flatness, the larger the bending moments acting on the tunnel lining become large, 2) in the same shape of tunnel face, the change of both value and distribution of bending moments does not present clear with increasing the overburdens, and 3) earth pressures on both gravity and centrifuge conditions show the good correlation with Terzaghi theoretical results under the confining coefficient K_0 between 0.5 and 1.0.On the other hand, three dimensional trapdoor experiments have been carried out under various overburdens so as to clarify the mechanical behavior and the deformability with the excavating tunnel, And then, under various overburdens, three dimensional trapdoor experiments in consideration of the tunnel intersection have been carried out. In consequence from three dimensional trapdoor experiments, 1) the earth pressures on the lowered trapdoor remarkable increase with descending trapdoor, 2) in case of the descending trapdoor streak, that is the assuming the tunnel excavation, the remarkable settlement can be observed on the lowered trapdoor since the ground above the lowered trapdoor has already been loosened, and 3) in case of small intersection angle under various overburdens, large earth pressures acting on the main tunnel can be observed when the branch trapdoors go down. Less

为了确立需求日益增加的超大工作面、长距离隧道的设计理念，进行了隧道衬砌模型试验和三维活板门试验。分析了隧道衬砌的弯矩和土压力，以及隧道开挖的机理。在隧道衬砌模拟试验中，假设在沙质地基上开挖，在重力和离心条件下进行了考虑不同覆盖层和掘进工作面形状的试验。在试验结果的基础上，讨论了隧道机理的影响因素，即作用在隧道衬砌上的土压力和弯矩、作用在隧道周围地面上的土压力和地表沉降。此外，利用Terzaghi土压力理论对作用在隧道衬砌上的土压力进行了理论讨论。结果表明：1)当隧道端面形状为平直时，作用在衬砌上的弯矩越大；2)当隧道端面形状相同时，弯矩的值和分布随覆盖层的增加变化不明显；3)当围系数K_0在0.5 ~ 1.0之间时，重力和离心条件下的土压力均与Terzaghi理论结果具有较好的相关性。另一方面，进行了不同覆盖层下的三维活板门试验，明确了其随开挖隧道的力学行为和变形能力，并在不同覆盖层下进行了考虑隧道相交的三维活板门试验。三维活板门实验结果表明：1)随着活板门的下降，下沉的活板门上的土压力显著增加；2)当活板门呈下降的条状时，即假设隧道开挖时，由于下沉的活板门上方的地面已经松动，下沉的活板门上可以观察到显著的沉降；分支活板门下移时，主隧道承受较大的土压力。少