宜万铁路下村坝隧道大型半充填溶洞处理技术

宜万铁路下村坝隧道施工中揭示大型半充填型溶洞——"+615"溶洞,溶洞处理难度大,技术要求高,为确保施工及运营期隧道安全,在查清溶洞发育地质特征的基础上,研究安全可靠、经济适用的综合处理方案。根据溶洞发育规模、工程及水文地质条件综合考虑隧道工程修建技术特点,经理论计算、工程类比,对"+615"大型半充填溶洞提出了"拱部回填砂浆稳定危岩、隧底桩基承台结构跨越溶洞、洞身加强型复合式衬砌结构"相结合的综合处理技术。结果表明,工程实践效果较好,隧道结构安全可靠。

Treatment Technology of Half-Filled Karst Cave for Xiacunba Tunnel on Yichang-Wanzhou Railway

During excavation of the Xiacunba Tunnel on the Yichang-Wanzhou Railway,a large half-filled karst cave was revealed,this was the"+615"karst cave,of which the treatment construction was difficult and with very strict technical requirement. In order to ensure construction and operation safety of the tunnel,this paper investigated and researched the geological characteristics of the karst cave development,and then researched on a safe,reliable,economical and suitable comprehensive treatment scheme. Moreover,the technical characteristic of the tunnel construction was analyzed based on the karst cave's development scale and hydro-geological condition. Finally,by means of theoretical calculation and engineering analogy,this paper proposed a comprehensive technical scheme for the treatment of the "+615"large half-filled karst cave,that was: stabilizing the dangerous rocks by backfilling mortar at tunnel's arch ring,striding over the karst cave by bearing platform of pile foundation at tunnel bottom,and strengthening tunnel trunk by composite lining. It is proved by practice that this scheme of treatment technology is safe,effective and reliable,and can serve as a reference for similar projects in future.