单洞双层大断面地铁止水施工技术研究

深圳地铁一期工程4A标段的单洞双层大断面地铁施工目前在国内极为少见，且地层上软下硬、地下水极为发育，地下水位高，水压力大，整个隧道开挖过程不允许出现地面塌陷、突水和涌砂现象，给施工止水带来一定困难。施工难度很大。通过地面注浆止水帷幕、洞内小导管注浆加固和冷冻止水帷幕等施工研究，较好地解决了施工难题。

Study on Water- seal Construction Technique Used in the Subway with Single- Cave, Double- deck and Large Sections

The construction of the subway with single-cave, double-deck and large section of A4 tender section of the first-stage construction of Shenzhen Subway is very seldom seen at home recently. The stratum layer is soft in the upper and hard in the lower, the ground water is very developed with higher level and bigger pressure, and there is the inadmissibility of collapsing, swelling and mud rushing in the course of excavation of the whole tunnel. So the water-seal in the construction is very difficult. And the ejection for water plugging on the ground, the ejection for water plugging through small catheter's strengthening and freezing in the cave and other construction methods studies have better solved this construction difficulty.