合肥地铁单线膨胀土浅埋暗挖隧道预加固措施研究

合肥地铁1号线试验段终点—云谷路站浅埋暗挖区间穿越膨胀土地层，因膨胀土的胀缩性、裂隙性等不良工程特性会对施工造成一定影响，选取合适的预加固措施能有效降低其影响。小跨度膨胀土隧道常采用的预加固措施有超前锚杆、超前小导管注浆、管棚等，通过数值计算，分析了超前小导管注浆对隧道稳定性的影响，并建议合肥地区浅埋暗挖隧道施工不进行小导管注浆。

Study on Pre-reinforcement Measures of Shallow-buried Excavation tunnel of Single-line Subway Passing through Expansive Soil in Hefei

The shallow-buried excavation tunnel in the end of test section to Yungu road station of Hefei metro line 1 passes through expansive soil. Due to the poor expansive engineering characteristics, such as swell-shrink characteristic and cranny property, it will affect the tunnel construction. Reasonable pre-reinforcement measures can effectively reduce the impact. Forepoling bolt, advanced small pipe grouting and pipe roof are always used in small span expansive soil tunnel. The effect of advanced small pipe grouting on the stability of tunnel is analyzed through numerical calculation and advanced small pipe grouting is not suggested in shallow-buried excavation tunnel in Hefei.