【摘要】 管幕冻结法是利用管幕配合冻结止水措施解决复杂建设条件下暗挖施工的一种创新性工法,该工法利用管幕顶管内冻结管路对管间土体进行冻结止水,在顶管管幕和冻结土体的超前支护下实施隧道暗挖施工。文章以港珠澳大桥珠海连接线拱北隧道冻结方案为例,利用数值模拟手段对积极冻结期不同土层的冻结效果及圆形冻结管、异形冻结管开启时间进行了研究,结果表明圆形冻结管和异形冻结管宜同步开启。对维护冻结期开挖断面温度、风速进行模拟分析,结果表明开挖断面内空气温度宜控制在25℃,风速对冻结效果影响不大。更多还原

【Abstract】 Freezing-sealing pipe roof method( FSPR) is an innovative method and it utilizes pipe roof and freezing-sealing for tunnel construction under complicated conditions. This method employs artificial ground freezing method( AFG) for sealing up of soil between pipes by freezing,and then the construction is carried out under the forepoling of pipe roof and frozen curtain. Based on FSPR method for Gongbei Tunnel,a part of Zhuhai Link Road in Hong Kong-Zhuhai-Macao Bridge project,this paper studies the effect of water sealing of different soil layers and switching time of master and enhancing tubes during active freezing phase using numerical simulation method. The results show that it is suitable for master tube and enhancing tubes to be opened at the same time. Then the air temperature and wind speed of excavating face during maintain-freezing phase is analyzed. It concludes that the air temperature is suggested to be controlled below 25 ℃ in excavating face and the wind speed has minor influence on freezing effect.更多还原