基于新意法理念的连拱隧道设计施工优化

Design and Construction Optimization of Multi-arch Tunnel Based on ADECO-RS Method

新意法(ADECO-RS)是目前软弱围岩隧道施工的研究热点,通过采用三维地质建模技术建立乌龙山隧道的三维地质模型,基于新意法的核心理念通过FLAC3D程序对乌龙山隧道中导洞的全断面开挖过程进行了仿真分析。结果表明:在洞口超前管棚作用范围之内,全断面开挖时可无需对掌子面进行预加固;在管棚作用范围之外,通过对掌子面预加固后的不同工况模拟分析,得出玻璃纤维筋可以有效控制顶拱沉降以及减小掌子面挤出位移,用玻璃纤维筋加固掌子面后,顶拱沉降减少约40%,掌子面挤出变形减少约70%,极大提高了掌子面的安全系数可实现每循环最大进尺三榀钢架(1.8 m)的全断面快速开挖,并提出以不同搭接长度对应的掌子面挤出位移的曲线拐点来确定玻璃纤维筋的最小搭接长度。研究结果可为五级围岩的小断面隧道快速开挖提供借鉴。

ADECO-RS method is the research focus of tunnel construction in soft surrounding rock,3D geological modeling techno-logy was used to to establish the true 3D geological model of Wulongshan Tunnel,based on the core idea of the ADECO-RS,simulation calculation was carried out through FLAC^(3D) program,the construction method of full section excavation in the tunnel was optimized.The results show that there is no need to pre-reinforce the tunnel face within the scope of action of the large pipe shed,outside the scope of the pipe shed,through the simulation and analysis of the different working conditions after the pre-reinforcement of the palm face,the glass fiber bars can effectively control the settlement of the top arch and reduce the extrusion displacement of the palm surface.After the glass fiber bars were used to strengthen the palm surface,the settlement of the top arch is reduced by about 40%,and the extrusion deformation of the palm surface is reduced by about 70%,the safety factor of the tunnel face is greatly improved,and the full section rapid excavation of three steel frames(1.8 m)with the maximum footage per cycle can be realized and the curve inflection point of extrusion displacement of palm surface corresponding to different lap lengths was proposed to determine the minimum lap length of fiberglass bolt.The research results can provide reference for the rapid excavation of small section tunnel with five grade surrounding rock.