尼泊尔上马相迪A水电站砂卵石隧洞开挖施工技术分析与应用

Analysis and Application of Tunnel Excavation Technology in Sandy Gravel of Upper Marsyangdi A Hydropower Station in Nepal

上马相迪A水电站位于尼泊尔西部GANDAKI地区马相迪河的上游河段上,是以发电为主的径流引水式枢纽工程,引水隧洞0+98.00m^0+342.00m段为砂卵石地层,通过“洞口扩大拱、洞口防渗、超前预支护、预留核心土法、台阶法、减震爆破掏心技术、安全观测”等措施安全开挖贯通。经收敛变形观测,洞室整体稳定。

Upper Marsyangdi A Hydropower Station is located on the upper reaches of the Marsyangdi River in the GANDAKI area of western Nepal. It is a runoff diversion project with main function of power generation. The 0+98.00 m^0+342.00 m section of the headrace tunnel is located in sandy gravel stratum. Measures such as expanding the arch at the portal, seepage prevention, pre-supporting, reserving the core soil method, step method, shock blasting and center excavation technology, and safety observation are adopted for the safe excavation of the tunnel. Through convergence deformation observation, the excavated cavity is generally stable.