ISSN 2096-4498
CN 44-1745/U
Tunnel Construction ›› 2018, Vol. 38 ›› Issue (4): 545-550.DOI: 10.3973/j.issn.2096-4498.2018.04.003
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YANG Jianmin, SHU Dongli, ZHANG Han, ZHU Linchen
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Abstract:
The problem of large deformation of primary support during soft rock tunnel excavation is studied by taking the large crosssection loess tunnels on ZhengzhouXi′an Highspeed Railway and tunnels on ChengduKunming Railway in Tertiary Xigeda Fm with soft and weak surrounding rocks for examples. The causes of large settlement of soft rock tunnel primary support and its countermeasures are analyzed by theoretical calculation and site monitoring methods. The study results are drawn as follows: (1) The settlement of soft rock tunnel mostly exceeds 20 cm; and the main cause of large settlement of primary support is the overlarge pressure (897.4 kN in maximum) on arch foot, which significantly exceeds the bearing capacity of arch foot(arch springing). (2) The largest pressure of feetlock bolt is 55 kN, which occurs close to the steel frame; the pressurebearing property of large arch foot is significant and the extreme value is 0.9-1.7 MPa. (3) The methods of adding feetlock bolt (pipe), expanding arch foot and closing inverted arch timely are the keys to control the settlement of primary support of soft rock tunnel.
Key words: soft rock tunnel, primary support, settlement mechanism, control measures
CLC Number:
U 45
YANG Jianmin, SHU Dongli, ZHANG Han, ZHU Linchen. Research on Settlement Mechanism of Primary Support of Soft Rock Tunnel and Its Countermeasures[J]. Tunnel Construction, 2018, 38(4): 545-550.
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http://www.suidaojs.com/EN/Y2018/V38/I4/545