函谷关隧道下穿新黄土冲沟施工技术

Technology for Construction of Hanguguan Tunnel Under-passing New Loess Gulch

研究目的:研究大断面隧道下穿新黄土冲沟地段施工中的偏压影响,提出防止隧道坍塌的施工技术。研究结论:(1)水泥土回填、混凝土明渠修筑及混凝土咬合桩打设等技术措施,防止了地表水下渗、浸蚀,消除了地表水对湿陷性黄土的影响,提高了冲沟及其边坡的稳定性;(2)应用水玻璃硫酸浆液注浆固结粉砂层等加固措施,减少了因隧道开挖引起的地表沉降,保证了隧道开挖的稳定性;(3)提高隧道初期支护强度和刚度,控制隧道开挖支护变形,可有效控制隧道偏压的影响;(4)通过CRD工法优化,缩短工序距离和工序时间,可以达到初期支护早日成环,对控制黄土隧道变形和地表下沉行之有效。

Research purposes： The study is done on the influences of construction of the tunnel under - passing new loess gulch on the bias and the construction technology is presented to prevent tunnel collapse.Research conclusions： （ 1 ） To take some measures, such as refilling soil - cement, building concrete ditch, driving biting piles, can prevent the penetration and corruption of ground water, eliminate the impact of ground water on collapsible loess and enhance the stability of gulch and side slope. （2） To consolidate sand strata with sodium silicate grouting can reduce the surface subsidence caused by tunneling and guarantee the tunneling stability. （3）To enhance the strength and rigidity of the primary support for tunnel lining can control the support deformation caused by tunneling and effectively control the influences of the tunnel bias （4） To optimize CRD construction method can shorten the distance and time of working procedure and make the primary lining forming a circle as soon as possible to well control the tunnel deformation and surface subsidence.