首页|地表堆卸载对浅覆土盾构隧道影响试验研究

地表堆卸载对浅覆土盾构隧道影响试验研究

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地铁沿线开发利用过程中不可避免地造成紧邻地铁隧道的地表临时堆载,堆载清除后依然会对隧道结构造成不可恢复变形,影响地铁安全运营.现有的研究主要集中在堆载过程引起的盾构隧道变形,缺少堆载-卸载这一完整过程的研究.为探究地表堆-卸载引起的浅覆土隧道变形特性,以错缝无榫槽盾构隧道为原型,使用3D打印技术制作的盾构隧道模型开展砂土地层盾构隧道的浅覆土堆-卸载试验和常覆土堆载试验,分析浅覆土隧道堆-卸载过程受力及变形情况,并对比堆载过程浅覆土隧道与常覆土隧道受力及变形结果.实验结果表明:地表堆-卸载过程引起隧道管环变形由整体沉降和径向收敛2个部分组成.地表临时堆载引起隧道的部分变形是不可逆的,且浅覆土隧道的卸载回弹变形具有一定的滞后性,卸载后,隧道环的不可恢复位移偏移量:拱底>拱顶>拱腰.距离荷载中心越近,截面椭圆化越明显,且拱顶、拱底和拱腰是产生弯矩的峰值处.浅覆土隧道对地表荷载变化更敏感,在地表堆载下产生明显的沉降区,且隧道两端发生翘起现象;常覆土隧道差异沉降相对较小,沉降曲线较平滑.浅覆土隧道受到附加应力更大,但受影响范围要小于常覆土隧道.研究可为地表突发堆载中既有盾构隧道的保护提供理论依据.
Experimental investigation on effect of surface loading and unloading on shield tunnel with shallow overburden
The temporary surface surcharge above tunnels is inevitable due to the frequent construction activities along the subway.Although the surcharge was soon removed,the tunnel structure still suffered irreversible deformation,which threatened the safety of subway operation.Previous studies mainly focused on the tunnel deformation caused by the surcharge,while ignored the tunnel deformation during the unloading process after surcharge.The purpose of this experiment was to explore the deformation characteristics of shallow tunnel caused by surface loading-unloading.The scaled tunnel model in this experiment made by 3D Printing technology was based on the shield tunnel with staggered segment without tenon-and-groove.This tunnel model was used for the loading-unloading scale experiment above the shallow-buried tunnel and the loading scale experiment above the normal overburden tunnel in sandy.Then the stress and deformation of shallow tunnel in the loading-unloading process were analyzed,and the difference of stress and deformation between shallow tunnel and normal tunnel during loading were also compared.The experimental data show that the tunnel deformation caused by temporary surface surcharge consists of overall settlement and radial deformation.Some normal performance of the shield tunnel is disrupted due to surcharge,and the resilience of shallow shield tunnel by unloading of the surcharge has a certain hysteresis.The unrecovered offset of the tunnel ring after unloading is the largest at the arch bottom,followed by the arch crown,and the smallest at the arch waist.In addition,the closer to the surcharge center,the more elliptical the ring section is,and arch crown,arch bottom and arch waist are the places where the peak moment occurs.The shallow tunnel is more sensitive to the change of surcharge,which occurs obvious settlement area under the surcharge,while the two ends of the tunnel slightly rise.On the contrary,the differential settlement of the normal tunnel is relatively small,and its settlement curve is relatively smooth.Shallow tunnel is subject to more additional stress,while the affected range is smaller than that of the normal tunnel.These results describe the deformation characteristics of shallow shield tunnel caused by surface loading-unloading,which may provide some theoretical basis for the protection of existing shield tunnel under sudden surface surcharge.

shallow shield tunnel3D Printingtemporary surface surchargeunloading resilienceexperimentation of physical model

符宇坤、康成、梁荣柱、向黎明、王理想、柯宅邦、吴小建

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中国地质大学(武汉) 工程学院,湖北 武汉 430074

广西大学 土木建筑工程学院,广西 南宁 530004

安徽省建筑科学研究设计院,安徽 合肥 230031

绿色建筑与装配式建造安徽省重点实验室,安徽 合肥 230031

上海建工集团有限公司,上海 200080

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浅覆土盾构隧道 3D打印 地表临时堆载 卸载回弹 模型试验

中国博士后基金资助项目安徽省建筑科学研究设计院科研项目安徽省建筑科学研究设计院科研项目安徽省住房城乡建设科技计划项目

2019M6533082018JKY-262021-52ZC2020-YF44

2024

10.19713/j.cnki.43-1423/u.T20230118

铁道科学与工程学报
中南大学 中国铁道学会

铁道科学与工程学报

CSTPCD北大核心EI
影响因子：0.837
ISSN：1672-7029
年,卷(期)：2024.21(1)
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