地铁车站开挖引起地表沉降分析方法的对比研究

COMPARATIVE STUDY OF ANALYTICAL METHODS FOR GROUND SURFACE SETTELMENT INDUCED BY SUBWAY STATION CONSTRUCTION

地铁隧道开挖过程引起的地表沉降会对周围环境造成一定的影响。结合青岛地铁车站开挖引起地表沉降过大的问题,首先,以该车站地表沉降实测数据为基础,利用Peck方法得到车站开挖引起的沉降槽宽度、地层损失率,拟合地表沉降槽曲线。并对该地铁车站开挖引起的地表沉降槽宽度的计算表达式给出建议。其次,利用随机介质理论方法反分析地铁车站初步开挖引起的地表移动参数,包括沉降槽影响范围以及断面收缩率,并利用所得的参数对该车站的进一步开挖进行地表沉降预测。最后,在将Peck方法和随机介质理论方法对比分析的基础上,得到2种方法对于地表沉降影响范围计算结果的差异;为了进一步验证该结论的正确性,利用反分析的方法得到我国部分城市隧道开挖引起的地表移动参数,并将开挖地层影响角换算为沉降槽宽度与现有的计算结果进行对比分析。

Ground surface settlement induced by tunneling will affect the surrounding environment.Taking into account the problem of excessive ground settlement,analysis of field measurements of a Qingdao metro station is conducted to acquire empirical estimations of relevant characteristic parameters.First,according to the obtained settlement trough width and soil loss rates,the fitting curve of ground surface settlement trough was obtained using Peck method;and the recommendation of settlement trough width formula is given.Second,the fundamental ground surface moving parameters are obtained by using inverse analytical method based on ground surface measurement data of initial excavation.Furthermore,by using the scaling method,the ground surface moving parameters of the further excavation can be obtained,and eventually the ground surface movement of the whole tunnel due to the excavation can be predicted.Finally,the difference of the results of the two methods is obtained based on comparative analysis.In order to verify the correctness of this conclusion,impact angle caused by tunnel excavation of some cities in China is analyzed and converted into settlement trough width for comparison with existing achievements.