隧道原位扩建对邻近建筑物影响评估的研究

以重庆机场路渝洲隧道原位车道扩建为8车道工程为背景，通过文献调研、数值分析、监控量测和爆破监测等手段，对隧道原位扩建形式比选、扩建开挖对邻近建筑物变形影响和扩建爆破作业对邻近建构筑物影响等开展研究, 得到如下结论：（1）隧道原位扩建有单侧扩建、两侧扩建和周围扩建3 种形式，从施工力学分析，单侧扩建形式最优；（2）渝州隧道地表最大沉降曲线与小净距隧道类似；（3）地表沉降槽曲线的影响半径为40 m左右；（4）渝州隧道最大地表沉降差距离中线约10 m和30 m，实测临近建筑物沉降满足规范，建筑物安全；（5）爆破振动监测显示临近隧道和建筑物的振速值均远低于规范限制值，说明既有隧道形成的临空面对于吸收和释放爆破振动能量的作用很大。该研究成果为今后类似隧道原位扩建工程的施工方案提供参考借鉴。

Research on influences of in-situ tunnel extension project on adjacent buildings

The 2×2 lane Yuzhou Tunnel was extended to 4×4 lane tunnel in Chongqing airport road. Taking this project as an engineering background, the influences of in situ extension of the tunnel excavation on adjacent buildings and blasting effect on adjacent buildings are studied. The main study methods include the literature research, numerical analysis, monitoring measurement and blasting monitoring. The main conclusions are drawn as follows. (1) Unilateral expansion, both sides extension and around extension are the three tunnel extension method in situ, by construction mechanics analysis, the unilateral extension is optimal; (2) maximum surface settlement curves of extension tunnel are similar with neighborhood tunnel; (3) radius of surface settlement trough curve is about 40 m; (4) the max surface settlement differential is about 10 m and 30 m distance from the center line. The building settlement meets the specifications, and the buildings are safe; (5) blasting vibration monitoring data indicate that the vibration speed of the near building and tunnel is below the specification limit, which indicates that the free face of the existing tunnel absorbs and releases most of blasting vibration energy. The research results provide a reference for similar tunnels in situ extension project.