西安建筑科技大学学报(自然科学版)

依托新建兰渝高铁桃树坪富水弱胶结粉细砂隧道工程,基于现场监测和数值模拟分析相结合的方法,对大断面富水砂地层条件下的隧道施工方案进行了优化和分析,研究了大断面隧道CRD法、双侧壁导坑法和三台阶七步法三种施工方案的优缺点,改进了大断面隧道双侧壁导坑法施工技术,提出了“底部双导洞超前施工”的新工法.跟踪桃树坪隧道3#斜井施工工区底部双导洞超前工法试验段进行的现场围岩压力、拱顶沉降和水平位移的现场监测,验证了工法的安全、可行性; 基于数值模拟分析,确定了施工中上半断面的最佳开挖高度 5.4 m,超前导洞1部与上半断面5部间合理步距25 m,优化了底部双导洞超前施工工法的技术参数,为富水弱胶结粉细砂地层隧道的施工提供了技术保障.

Taoshuping tunnel in the newly constructed Lanzhou-Chongqing railway, has a complicated geological condition of rich water and weak cemented fine sand. Combined with the method of in-situ monitoring and numerical simulation, the large cross-section tunnel construction scheme under the geological condition of rich-water and fine sand are analyzed and optimized. On the basis of comparing the advantages and disadvantages by CRD method, double-side-drift method and three steps seven footwork excavation method, the double-side-drift method for large cross-section is improved and a new method of bottom advanced double-drift method is proposed. The security and feasibility of the new method are proved by in-situ monitoring the surrounding rock pressure, vault settlement and horizontal convergence of Taoshuping tunnel 3# inclined shaft's test section. Based on the numerical simulation, the technical parameters for the new method is optimized. The simulation results show that the optimum excavation height of upper section is 5.4 m and the most reasonable step distance between the 1st part(advanced double-drift)and the 5th part(upper section)is 25 m. The research results provided a technical support for tunnel construction under the condition of rich and weak cemented fine sand stratum.

引言
1 工程概况
2 隧道施工方案确定及现场试验
3 数值模拟研究
4 结论

图1 桃树坪隧道地质纵断面图
Fig.1 The geological profile of Taoshuping tunnel

图2 桃树坪隧道施工中涌水现象<br/>Fig.2 The water burst phenomenon during the construction of Taoshuping tunnel

图2 桃树坪隧道施工中涌水现象
Fig.2 The water burst phenomenon during the construction of Taoshuping tunnel

图3 桃树坪隧道施工中涌沙现象<br/>Fig.3 The sand inrush phenomenon during the construction of Taoshuping tunnel

图3 桃树坪隧道施工中涌沙现象
Fig.3 The sand inrush phenomenon during the construction of Taoshuping tunnel

表1 隧道开挖方案对比表<br/>Tab.1 The comparison of tunnel excavation scheme

表1 隧道开挖方案对比表
Tab.1 The comparison of tunnel excavation scheme

图4 隧道施工横、纵断面设计图<br/>Fig.4 The vertical and cross section of tunnel construction

图4 隧道施工横、纵断面设计图
Fig.4 The vertical and cross section of tunnel construction

图5 试验段工法转化<br/>Fig.5 The construction method transition of the test section

图5 试验段工法转化
Fig.5 The construction method transition of the test section

图6 围岩压力最大值分布/kPa<br/>Fig.6 The distribution of maximum surrounding rock pressure/kPa

图6 围岩压力最大值分布/kPa
Fig.6 The distribution of maximum surrounding rock pressure/kPa

图7 隧道拱顶、拱肩及导洞位移时程曲线<br/>Fig.7 The time-history curve of tunnel vault, arch foots and heading pilots displacement

图7 隧道拱顶、拱肩及导洞位移时程曲线
Fig.7 The time-history curve of tunnel vault, arch foots and heading pilots displacement

表2 围岩及各种支护参数<br/>Tab.2 Parameters of surrounding rock and support

表2 围岩及各种支护参数
Tab.2 Parameters of surrounding rock and support

图8 隧道开挖顺序<br/>Fig.8 The excavation sequence of tunnel

图8 隧道开挖顺序
Fig.8 The excavation sequence of tunnel

表3 不同上半断面高度施工引起的拱顶位移对比<br/>Tab.3 Comparison of vault displacement caused by

表3 不同上半断面高度施工引起的拱顶位移对比
Tab.3 Comparison of vault displacement caused by

表4 不同的开挖步距引起围岩压力及位移的对比<br/>Tab.4 The comparison of surrounding rock pressure and displacement is caused by different excavation steps

表4 不同的开挖步距引起围岩压力及位移的对比
Tab.4 The comparison of surrounding rock pressure and displacement is caused by different excavation steps

图9 数值模拟沉降曲线<br/>Fig.9 Numerical simulation results of the settlement

图9 数值模拟沉降曲线
Fig.9 Numerical simulation results of the settlement

图10 数值模拟收敛曲线

图11 支护结构受力云图<br/>Fig.11 Stress nephogram of support structure

图11 支护结构受力云图
Fig.11 Stress nephogram of support structure

图12 临时支护拆除前后支护应力变化<br/>Fig.12 The variation of support stress before and after remove the temporary support

图12 临时支护拆除前后支护应力变化
Fig.12 The variation of support stress before and after remove the temporary support

图13 围岩塑性区<br/>Fig.13 Plastic zone of surrounding rock

图13 围岩塑性区
Fig.13 Plastic zone of surrounding rock

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备注

引言

1 工程概况

2 隧道施工方案确定及现场试验

3 数值模拟研究

4 结论

期刊信息