西安建筑科技大学学报(自然科学版)

若隧道洞口开挖时未采取合理的边坡加固措施,易导致边坡产生开裂、滑坡甚至崩塌等危害.以格鲁吉亚F3标5号公路隧道为背景,探讨了隧道洞口在微型桩墙支护和锚网喷支护两种加固方案下,隧道开挖引起的围岩位移场及应力场变化特征.利用有限元分析软件MIDAS-GTS建立三维模型,模拟隧道施工过程,并结合实际工程监测数据,对比研究了两种支护方案优劣性.结果表明:锚网喷支护方案围岩最大横纵向位移分别为3.55 mm和8.73 mm,最大拉应力为1.91 MPa; 衬砌沿隧道开挖方向的最大弯矩为33.71 kN·m,最大横向位移为3.55 mm.锚网喷支护方案较微型桩墙支护方案更为有效,显著提高了洞口边坡稳定性.因此,锚网喷支护方案在该地形中更具合理性.其结论对山岭地区公路隧道的建设提供一定的指导作用.

Unreasonable slope reinforcement measures during excavation of tunnel portals can easily lead to the damage of slope cracking, landslide or even collapse. In this paper, taking the No.5 highway tunnel in the F3 bid of Georgia as an example, the displacement and stress field changes of surrounding rock caused by tunnel excavation are discussed under the two reinforcement measures of micro pile-wall support and bolt-mesh-spurting supporting. The finite element analysis software MIDAS-GTS is used to establish a three-dimensional model to simulate the tunnel construction process, and combined with the actual project monitoring data, the advantages and disadvantages of the two support schemes are compared. The results show that the maximum transverse and longitudinal displacements of the surrounding rock are 3.55 mm and 8.73 mm respectively, and the maximum tensile stress is 1.91 MPa. The maximum bending moment of lining along the tunnel excavation direction is 33.71 kN·m, and the maximum transverse displacement is 3.55 mm. The anchor net spray support scheme is more effective than the micro pile wall support scheme, which significantly improves the stability of the portal slope. Therefore, the anchor net spray support scheme is more reasonable in this terrain. The conclusion can provide some guidance for the construction of highway tunnels in mountainous areas.

引言
1 工程背景
2 数值模拟
3 数值模拟结果及分析
4 现场监测分析
5 结论

图1 工程概况图
Fig.1 Project overview

图2 隧道洞口横断面图<br/>Fig.2 Cross section of tunnel portal

图2 隧道洞口横断面图
Fig.2 Cross section of tunnel portal

图3 两种洞口支护设计方案模型对比图<br/>Fig.3 Comparison of original design and optimization model

图3 两种洞口支护设计方案模型对比图
Fig.3 Comparison of original design and optimization model

表1 模型材料参数<br/>Tab.1 Model material parameters

表1 模型材料参数
Tab.1 Model material parameters

图4 围岩横向水平位移<br/>Fig.4 Horizontal displacement of surrounding rock

图4 围岩横向水平位移
Fig.4 Horizontal displacement of surrounding rock

图5 围岩纵向垂直位移<br/>Fig.5 Vertical displacement of surrounding rock

图5 围岩纵向垂直位移
Fig.5 Vertical displacement of surrounding rock

表2 两种设计引起的位移结果对比<br/>Tab.2 Comparison of displacement results caused by two designs

表2 两种设计引起的位移结果对比
Tab.2 Comparison of displacement results caused by two designs

图6 围岩第一主应力云图<br/>Fig.6 The first principal stress nephogram of surrounding rock

图6 围岩第一主应力云图
Fig.6 The first principal stress nephogram of surrounding rock

表3 两种设计产生的应力结果对比<br/>Tab.3 Comparison of stress results between two designs

表3 两种设计产生的应力结果对比
Tab.3 Comparison of stress results between two designs

图7 隧道衬砌弯矩图<br/>Fig.7 Bending moment diagram of tunnel lining

图7 隧道衬砌弯矩图
Fig.7 Bending moment diagram of tunnel lining

图8 隧道衬砌横向水平位移<br/>Fig.8 Horizontal displacement of tunnel lining

图8 隧道衬砌横向水平位移
Fig.8 Horizontal displacement of tunnel lining

图9 设计安全系数及塑性区<br/>Fig.9 Safety factor and plastic zone

图9 设计安全系数及塑性区
Fig.9 Safety factor and plastic zone

图10 洞口段地表监测点布置图<br/>Fig.10 Layout diagram of monitoring points for surface settlement

图10 洞口段地表监测点布置图
Fig.10 Layout diagram of monitoring points for surface settlement

图11 地表测点沉降<br/>Fig.11 Settlement of surface measurement points

图11 地表测点沉降
Fig.11 Settlement of surface measurement points

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备注

引言

1 工程背景

2 数值模拟

3 数值模拟结果及分析

4 现场监测分析

5 结论

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