复杂地铁车站施工对邻近建筑物变形影响数值分析的位移叠加法

Displacement superposition method of numerical analysis for determining influence of complex metro station construction on deformation of adjacent buildings

换乘地铁车站基坑工程地下空间布局复杂,由垂直交叉的地铁车站基坑工程、联络通道、区间隧道等共同组成,通常采用数值模拟方法分析基坑施工对邻近建筑物的变形影响。由于空间结构复杂、基坑规模大,采用整体模型来模拟施工过程建模困难,网格数量多,单台微机难以完成。为了解决这个问题,在合肥市潜山路地铁车站的数值模拟计算中采用位移叠加法,把复杂的地铁基坑工程计算模型剖分为整体模型和一个局部模型,将整体模型计算的变形结果作为局部模型计算的初始位移场,在该基础上对局部模型进一步开挖模拟基坑工程施工对邻近建筑物的影响。以单元内插法和反距离加权插值法为例,通过两种方法导出整体模型的初始位移场,并将两种位移叠加法计算得到的结果与单独计算的结果进行对比。结果表明,采用位移叠加法得到的计算结果与单独计算得到的结果基本一致,可近似作为完整模型计算结果,证明了位移叠加法的可行性。通过比较可知,采用反距离加权插值法比单元内插法具有更高的精度,得到的计算结果更准确。研究结果对复杂基坑工程数值模拟计算有重要的参考和应用价值。

Space distribution of foundation pit engineering for metro transfer station, which consists of vertically crossed station excavation, connected aisle and running tunnel, is complex. Numerical simulation method is usually used to analyze the construction impact of pit on adjacent buildings. Because of complicated structure and large excavation size, it is difficult to establish an integrated model to simulate construction process with single microcomputer; and numerical method does not work smoothly due to a large number of grids. In the numerical simulation of Qianshan Road metro station in Hefei, in order to overcome this problem, the complex metro foundation pit is divided into global model and one local model. The ultimate results of global model will be exported as a result of initial displacement field in local model; and then the local model is further excavated to study the influence of pit construction on neighboring buildings. Taking inverse distance weighted method and elementary interpolation method for examples,two kinds of initial displacement field of local model will be obtained by these two approaches. The calculating results of two methods are compared. It is shown that the results obtained by using displacement superposition method, which is consistent with the ones obtained by calculating separately, can used as the results of overall model approximately. The feasibility of displacement superposition method is verified. Comparing the inverse distance weighted with the elementary interpolation method, the former has a higher precision than the latter. The results play a guiding role in numerical simulation of complex foundation pit engineering.