长沙起伏板岩地层盾构施工地表沉降预测研究

A study on predicting the surface settlement caused by shield tunneling in slate- based fluctuated strata in Changsha

为有效指导起伏板岩地层盾构施工，保证施工安全，以长沙地铁2号线西延线一期工程为工程背景，通过数据统计分析、数值模拟等方法对湘江以西地区起伏板岩地层盾构施工地表沉降预测方法进行研究，包括地表有、无建筑物两种情况。研究结果表明：通过对依托工程单线盾构隧道施工地表沉降实测数据进行拟合分析，发现沉降曲线与Peck曲线吻合较好，表明Peck公式在该地区的适用性；通过计算分析，该地区无建筑物地表沉降预测沉降槽宽度系数取值范围为0．4-0．6，地层损失率取值范围为0．6％～1．2％；从施工风险控制和工程应用观点出发，对于有建筑物时地表沉降预测方法进行了探讨，可以保守选用无建筑物预测方法。本文研究成果可为本地区类似工程施工提供借鉴。

Prediction method of surface settlements of slate -based fluctuated strata in west of Xiangjiang river area is studied to guide the construction and ensure safety. This research program based on project of first phase of west extension line of Changsha metro line 2, and the settlement prediction work is in the conditions of with and without buildings. The following 3 research conclusions are obtained： Settlement curve is in good agreement with Peck curve by fitting analysis, and Peck formula is testified applicable in this area. Through calculation and analysis of surface without building, the results show value of widths coefficient of settlement tank ranges from 0.4 to 0.6, value of ground loss ratio ranges from 0.6% to 1.2%. Prediction method of surface settlements with buildings is discussed from in terms of tunneling risk control and engineering applications. Prediction method of surface without buildings is recommended. It can provide a reference for the follow -up constructions in this area.