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以狮子洋隧道砂性地层段地质条件和施工资料为基础,建立有限差分数值计算模型.通过比较不同断面监测点随开挖进程的位移值,结果表明:先掘隧道围岩向中心收缩,上下部围岩变形明显大于两侧;后掘隧道对先掘隧道有横向外挤的作用,但对纵向几乎没有影响.对有、无渗流作用的2种工况的比较分析说明,起初渗流对围岩变形影响不大,但最终加剧了围岩的变形程度.提出了开挖面前方土体扰动的累积效应和累积效应曲线的确定方法,通过该曲线可确定土体扰动范围和程度,经过理论分析,认为影响土体位移速率的2个因素是土体与开挖面间距和盾构推力.
Based on the geological conditions and construction data of the limestone stratum in Shiziyang Tunnel, a finite difference numerical model was established.By comparing the displacement of monitoring points along the excavation process with different sections, the results show that: firstly, the tunnel surrounding rock shrinks to the center, The surrounding rock deformation is obviously greater than the two sides; the tunnel digging has lateral squeezing effect on the tunnel before digging, but it has almost no effect on the longitudinal direction.Comparison and analysis of the two working conditions with and without seepage show that the initial seepage to the surrounding Rock deformation has little effect, but ultimately aggravates the degree of deformation of surrounding rock.The cumulative effect and cumulative effect curve of soil disturbance in front of excavation face are proposed, and the range and degree of disturbance of soil mass can be determined by theory Analysis shows that the two factors that affect the rate of soil displacement are the distance between soil and excavation face and the thrust of shield.