摘要
胡麻岭隧道为兰渝线重点控制性工程,隧道中部通过长4 250 m的第三系弱胶结含水粉细砂岩,在地下水作用下,掌子面开挖扰动后工程性质迅速恶化,基本呈散砂、稀糊状,局部还伴有涌水涌砂现象,施工受阻。针对这种情况,洞内开展了集水井降水、井点降水、分步超前降水、边墙侧向深井降水、轻型井点(真空降水)、水平旋喷、注浆固结、冷冻固结等研究试验,确定采用洞内深井与轻型井点相结合施工降水方案。但受岩层地下水水头高、渗透系数小、洞内降水作业工序繁杂及降水后达到开挖条件的周期长等影响,施工进度滞缓,因此研究地表深井预降水。通过对工程场地水文地质条件、施工现状、工法等综合分析,进行现场水文地质试验,分析计算采用地表深井预降水的井间距离及设计深度。
Humaling Tunnel, an important controlling project of Lan-Yu Railway, goes through weakcementation aqueous silty sand rock of 4250 meters long in THYPERLINK ＂ javascript ：void（0）;＂ertiary. The construction is blocked due to the impact of groundwater, and encountered with loose sand orthin paste on account of disturbance after excavation, which makes the engineering works deterioratedrapidly. To solve this problem, experiments such as water-collecting well dewatering, well - pointsdewatering, advanced step by step dewatering, sidewall lateral deep well dewatering, light welldewatering （ vacuum dewatering ）, horizontal jet grouting, grouting consolidation and freezingconsolidation are employed out in the tunnel. The experimental results support the combination of deepwells and light wells. But the progress is sluggish because of the influence of high water head, the lowhydraulic conductivity, the complexity of dewatering process, the extended period from dewatering toexcavating. Thus, surface deep well dewatering is proposed and analyzed. This paper focuses on theanalysis of the hydrogeological conditions, construction status and construction method, on thehydrogeological experiments, and on the calculation of inter-well distance, designed depth and time ofsurface dewatering well arrangement.
出处
《铁道标准设计》
北大核心
2015年第7期116-119,共4页
Railway Standard Design
关键词
铁路隧道
第三系
富水砂岩
深井
降水
Railway tunnel
Tertiary
Water-rich sandstone
Deep well
Dewatering
