摘要
为探索明挖超大跨度叠层隧道合理断面形式及优化思路,依托望海路快速化改造工程,借助数值模拟手段,分析超大跨度叠层隧道结构受力特点,并对超大跨度叠层隧道断面形式选择、跨度优化及覆土影响进行了研究。结果表明:超大跨度叠层隧道存在顶底板弯矩过大、中板承受拉应力的问题,中板处于偏心受拉的原因为跨度过大及侧向土体对结构约束不足;大跨度明挖隧道微拱形断面受力性能最优,直墙平顶断面劣于直墙折板断面,综合考虑结构受力性能、断面利用率、经济性,对于明挖大跨度叠层隧道推荐采用直墙折板断面;对超大跨度叠层隧道结构而言,跨度的大小贡献了结构内力较大的比重,减小结构跨度对结构受力改善明显,尤其可大幅减轻中板轴力和弯矩,断面一在受力性能及工程用量方面综合优势最大;浅埋条件下,推荐顶板上覆土采用换填泡沫混凝土的方式减少上覆土容重,从而降低隧道结构顶板截面内力,改善顶板受力条件。
In order to explore the reasonable section form and optimization ideas of excavated oversized-span layered tunnel, relying on Wanghai Road Expressway Reconstruction Project, with the help of numerical simulation method, the structural force characteristics of oversized-span layered tunnel are analyzed. The selection of section form, the span optimization and the influence of covered soil for oversized-span layered tunnel are studied. The results show that there are problems of too large bending moment of the roof and floor, and the tensile stress in medium plate existing in the oversized-span layered tunnel. The reasons of the medium plate at the eccentrically pulled are the span too large and the insufficient restraint of the lateral soil to the structure. The force performance of the micro-arch section of the long-span excavated tunnel is the best. The straight-wall flat-roof section is inferior to the straight-wall folded-plate section. By considering the force performance, section utilization rate and economy of the structure, the straight-wall folded-plate section is recommended for the excavated long-span layered tunnel. For the structure of oversized-span layered tunnel, the span size contributes to the greater proportion of structural internal forces, decreases the structural span and the structural force is improved obviously, especially can greatly lighten the axial force and bending moment of the medium plate. Section 1 has the greatest comprehensive advantages in terms of force performance and engineering consumption. Under the condition of shallow burial, it is recommended to replace the overlying soil of roof with the foamed concrete to decrease the density of the overlying soil so as to reduce the internal force of the roof section of the tunnel structure and improve the force conditions of the roof plate.
作者
张光伟
孙超
答武强
余祖峰
ZHANG Guangwei;SUN Chao;DA Wuqiang;YU Zufeng
出处
《城市道桥与防洪》
2023年第2期241-245,共5页
Urban Roads Bridges & Flood Control
关键词
明挖隧道
叠层
超大跨度
受力特征
断面设计
excavated tunnel
layered
oversized span
force characteristic
section design
