【作者】 张志强； 何本国； 何川；

【Author】 ZHANG Zhiqiang,HE Benguo,HE Chuan (School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

【机构】 西南交通大学土木工程学院地下工程系；

【摘要】 与山岭隧道所不同,采用矿山法修建水底隧道,二次衬砌将承受很大外水压力,特别是穿越饱水破碎地层时,具有很大的施工风险。本文以厦门翔安海底隧道为工程背景,针对F4风化深槽地层,研究不同水位条件下,衬砌荷载与排放流量及排放方式之间相关关系。研究得出:当控制排放量为全排条件流量三分之一左右时,可卸掉80%外水压力;从环境和经济角度考虑,可将折减系数β=0.2作为水底隧道限量排放的设计基准值;从支护结构体系组成考虑,对于F4强风化深槽破碎围岩,必须施作注浆圈,才可以保证在水压、土压共同作用下衬砌结构安全,结果显示施作注浆圈能够减少衬砌作用荷载30～40%,提高安全系数几乎一倍;从主体结构受力特征看,水底隧道最不利受力位置在墻脚和仰拱,因此,无论是防水型还是排水型隧道,均应对仰拱形式及支护参数加强设计。更多还原

【Abstract】 Different from mountain tunnel,the lining of underwater tunnel built by mining method will bear enormous external water pressure.Specially,there is significant construction risk when it passes through saturated water stratum.Xiamen undersea tunnel is cited in this paper.In connection with deep weathering slot stratum, relationships between lining load,discharge and water level are researched under the different conditions of disposal methods.When controled discharge is one-third of the whole discharge,80 percents of external water pressure is reduced.From the view of environmental and economic point,reduction factor p=0.2 is should deems as baseline design for underwater tunnel.According to support system,grouting circle must be done for F4 deep weathering slot stratum,which could ensure the structural safety of the tunnel lining under the action of water pressure and earth pressure.The results showed that grouting circle can reduce 30~40 percents of external water pressure on lining and improve the safety factor one time.From view of forced characteristics of main structure, the most harmful places are wall footing and invert.Therefore,whether it is type waterproof-type tunnel or drainage-type tunnel,more attention is paid on design of invert form and support.更多还原