隧道穿越地层接触带施工关键技术模型试验研究

Model Test Study on Key Construction Technology of Tunnel Passing Through Contact Zone of Stratum

以银川—西安高速铁路贾塬隧道穿越地层接触带为工程背景,采用模型试验的方法探究了不同开挖工法和支护参数下隧道围岩位移、初期支护与围岩间的接触压力、钢拱架应力的变化规律,并通过现场监控测量数据验证了模型试验的可靠性。研究结果表明:隧道穿越红黏土与砂岩夹泥岩接触带地层时,拱顶和拱肩处的围岩变形及支护受力较大;三种开挖工法中,三台阶预留核心土法对围岩位移限制效果最好,支护受力更加均匀;钢拱架间距相比初期支护厚度对围岩位移和结构受力的影响有限。

Taking the Jiayuan tunnel of Yinchuan-Xi’an high speed railway passing through the contact zone of stratum as the engineering background,the variation laws of tunnel surrounding rock displacement,contact pressure between initial support and surrounding rock,the stress of steel arch stress under different excavation methods and support parameters were explored by using the method of model test,and the reliability of model test was verified by field monitoring and measurement data.The results show that when the tunnel passes through the contact zone stratum between red clay and sandstone with mudstone,the surrounding rock deformation and support stress at the vault and abutment are large.Among the three excavation methods,the three-step reserve core soil method has the best effect on limiting the displacement of surrounding rock and the support stress is more uniform.Compared with the initial support thickness,the steel arch frame spacing has limited influence on the displacement of surrounding rock and the stress of structure.