浅埋黄土隧道管棚加固支护效果数值模拟分析

基于通定高速公路某浅埋黄土隧道工程，采取三维数值模拟和现场监测等手段，对浅埋段渗流黄土隧道的加固支护方案进行研究，分析对黄土隧道浅埋段施行超前管棚加固支护的可行性。针对不同的加固支护措施进行数值模拟分析，结果发现：超前管棚支护下拱顶沉降量减小16.2%，初期支护的轴力最大值减小19.8%。监测结果表明：超前管棚支护与超前管棚+超前小导管支护两种工法并用所能减小的竖向位移的百分比（27.8%、28.1%）非常接近，但超前管棚支护能大大节省额外施作超前小导管的费用和时间，有效地控制了拱顶范围内的围岩变形，验证了超前管棚加固支护工法的经济性和有效性。

Numerical Simulation Analysis of Reinforcement Support Effect of Pipe Shed in Shallow Buried Loess Tunnel

Based on a shallow buried loess tunnel project of Tongding Expressway, 3D numerical simulation and field monitoring are adopted to study the reinforcement support scheme of the seepage loess tunnel in shallow buried section and analyze the feasibility of reinforcement support of shallow buried section of loess tunnel with advanced pipe shed. The numerical simulation and analysis are conducted for the different reinforcement support measures. The result shows that the settlement of the vault under the advanced pipe shed support is reduced by 16.2%, and the maximum axial force of the initial support is reduced by 19.8%. The monitoring results show that the percentages of vertical displacement reduction (27.8% and 28.1%) between the two methods of advanced pipe shed support and advanced pipe shed + advanced small conduit support are very similar, but the advanced pipe shed support can greatly save the cost and time of extra advanced small conduit application, which effectively control the surrounding rock deformation within the range of vault and verify the economy and effectiveness of advanced pipe shed reinforcement support method.