卸压孔设置对冻结暗挖隧道冻胀卸荷影响研究  

Effect of setting pressure relief holes on freezing expansion and unloading offrozen underground excavated tunnel

作　　者：黄建华 陈伟斌 严耿明 HUANG Jianhua;CHEN Weibin;YAN Gengming(College of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China;Key Laboratory of Underground Engineering of Fujian Province University,Fujian University of Technology,Fuzhou 350118,China;College of Civil Engineering,Fuzhou University,Fuzhou 350118,China)

机构地区：[1]福建理工大学土木工程学院,福建福州350118 [2]福建理工大学地下工程福建省高校重点实验室,福建福州350118 [3]福州大学土木工程学院,福建福州350118

出　　处：《人民长江》2024年第2期146-155,170,共11页Yangtze River

基　　金：国家自然科学基金项目(51678153);福建省自然科学基金项目(2017Y0024);福建工程学院校级科研项目(GY-Z17145)。

摘　　要：冻结法暗挖隧道施工中,冻胀常导致土体和隧道等发生大变形,给地铁隧道和周边环境以及建(构)筑物带来不利影响。以福州市滨海软土地层冻结暗挖隧道工程为例,通过对原型工程建模和非线性分析,综合实测数据及工程情况,分析冻胀变形分布规律和设置卸压孔前后冻结暗挖隧道的位移变化特点。研究结果表明:人工冻结加固技术结合卸压孔应用,对土体冻胀力的释放和冻胀变形的控制效果较好,与没有设置卸压孔时的地层相比,卸压孔在冻土帷幕冻结交圈形成后,为土体冻胀提供自由变形空间,降低了土体的冻胀位移和冻胀应力;冻结期末2个冻结暗挖隧道中心点纵向剖面处冻胀位移最大值由28.88 mm降至16.75 mm,冻胀应力最大值由335 kPa降至265 kPa,卸压作用效果明显。研究结果可为人工冻结暗挖隧道工程提供借鉴和参考。During construction of underground excavated tunnels using freezing method,frost heaving often leads to the excessive deformation of soil and tunnels,bringing adverse impacts on subway tunnels,surrounding environments and buildings.Taking a frozen underground excavated tunnel project in the coastal soft soil layer of Fuzhou City as an example,a nonlinear analysis for the prototype project was carried out.Based on measured data and engineering conditions,the distribution pattern of frost heave deformation and the displacement variation characteristics of frozen underground excavated tunnel before and after the setting of pressure relief holes were analyzed.The research results showed that the artificial freezing reinforcement technology combined with pressure relief holes had a better effect on the release of frost heaving pressure and the control of freezing expansion deformation.Compared with the stratum with no pressure relief holes,the pressure relief holes provided free deformation space for the frozen soil expansion after the formation of intersection circle of the permafrost curtain,thus reducing the freezing expansion displacement and freezing expansion stress of the soil.At the end of the freezing period,the maximum freezing displacement at the longitudinal profile of the center points of two frozen underground excavated tunnels was reduced from 28.88 mm to 16.67 mm,and the maximum freezing stress was reduced from 335 kPa to 265 kPa,showing obvious decompression effect.The study results can provide references for artificially frozen underground excavated tunnels.

关 键 词：冻结法 冻胀变形 卸压孔 位移场 暗挖隧道 

分 类 号：U455[建筑科学—桥梁与隧道工程] U231[交通运输工程—道路与铁道工程]