B样条在盾构隧道沉降曲线拟合中的应用

基坑施工不可避免会对邻近的盾构隧道沉降产生影响,进而影响盾构隧道结构健康。如何选择合适的方法对隧道沉降监测点数据进行拟合,找出基坑施工参数与盾构隧道沉降趋势之间的内在关系,对快速判别盾构隧道结构性能有重要意义。本文利用三次B样条曲线在连接点处曲率保持一致的独特优势,用该方法对某毗邻型基坑施工期间引起的盾构隧道沉降监测数据进行拟合,在此基础上绘制出施工前后盾构隧道累计沉降的曲率曲线,了解盾构隧道结构的整体受力状态。曲率曲线既能有效地寻找到隧道结构薄弱部位,又能通过与地铁保护区曲率控制标准进行对比,判断隧道结构受力是否超限,为隧道的健康评判提供准确依据。

Application of B-Spline Curve in Fitting on Shield Tunnel Settlement Curve

The foundation pit construction will inevitably affect the settlement of adjacent shield tunnel, and consequently the structure of shield tunnel. How to choose the appropriate method to fit the data of tunnel settlement monitoring points and find out the relationship between the foundation pit construction parameters and the settlement trend of the shield tunnel is very important for rapid identification of the performance of the shield tunnel. In this paper, the unique advantages of three B spline curves in the consistency of the curvature of the connecting points which is used to fit the data of settlement monitoring of shield tunnel during construction period. Based on these settlement curves, the curvature curves of accumulated settlement of shield tunnel are plotted, and the whole force state of shield tunnel is known. This is a useful method for the health evaluation of the tunnel structure because it can not only effectively find the weak parts of tunnel structure but also determine whether the tunnel structure is overloaded through comparing with the curvature control standard of metro protection zone, which provides accurate basis for health evaluation of the tunnel.