浅埋暗挖地下通道软土地层变形规律及预加固措施

采用有限元数值模拟方法,模拟在不采取预加固措施时厦门嘉禾园湖光路暗挖地下通道的施工过程。结果表明:深度越深地层沉降槽宽度越小,最大沉降值越大;掌子面通过后,地层水平位移曲线开始出现鼓包现象,从拱顶到通道底最大水平位移出现在通道侧墙中部靠上的位置;掌子面挤出位移呈现"四周小,中间大"的特征,最大位移出现在掌子面中心。据此提出高压旋喷桩结合长管棚预加固方案。经现场监测,该预加固方案控制地层变形效果明显。

Deformation Law and Pre-reinforcement Measures of Soft Soil Stratum for Excavation of Shallow-buried Underground Passage

The finite element numerical simulation method was used to simulate the construction process of the excavation underground passage without pre-reinforcement measures in Jiaheyuan lake light road of Xiamen. The results show that the deeper the depth,the smaller the width of formation settlement trough and the larger the maximum subsidence value is. The formation horizontal displacement curve begins to appear bulging phenomenon after the tunnel face excavation and the maximum horizontal displacement from the vault to the passage bottom appears at the upper position of the passage side wall. The extrusion displacement of tunnel face presents the characteristics of small around and large in the middle,and the maximum displacement occurs in the center of the tunnel face.Based on these law s,the pre-reinforcement scheme of high-pressure rotary jet grouting pile combined with long pipe shed was put forw ard. Through on-site monitoring,the pre-reinforcement scheme had obvious effect on controlling stratum deformation.