大断面开挖成型控制技术在三峡工程中的应用

Application of the excavation controlling techniques of large-section in the Three Gorges project

开挖成型控制是在大断面地下洞室开挖施工中的一项关键技术,开挖成型控制得好,既能降低后续施工的成本,又能提高工程的安全。在三峡工程某大型地下厂房开挖施工中,通过对造孔设备选型、精度控制及精细化装药等方面的研究和实践,取得了顶拱平均超挖8.5cm、边墙平均超挖5.3cm、岩锚梁平均超挖控制在2cm以内的结果,远低于规范所要求的小于20cm的标准,并且开挖平整度小于10cm,爆破半孔率达到了95%以上,在成型质量控制方面较以往工程有了突破性的进展,具有较高的应用及参考价值。对具体控制过程予以分析总结,供类似工程借鉴工程实例。

Excavation controlling is a key technique in the process of large-section underground excavation,we can not only reduce costs of follow-up construction,but also enhance security if we control the underground excavation well. Selecting equipments of drilling holes,controlling the holes precision and refinement of charging are researched into and practiced in a large-scale underground powerhouse of Three Gorges project. Good results show that we can work additional 8.5 cm for the roofs and 5.3 cm for the sidewalls than standard in average,and control the extra-mining of cantilever crane beam in 2 cm,much lower than 20 cm which is the standard of criterion. The flatness of excavation is less than 10 cm,and the half holes rat of blasting is more than 95 %. A breakthrough in the controlling of forming quality is achieved,and it is highly value able in application. This paper will analyze and aggregate the specific process of controlling to provide example for similar projects.