上软下硬地层盾构法隧道地表沉降的数值模拟预测

Numerical simulation and prediction of ground surface settlement of shield tunnel in upper-soft and lower-hard soil horizon

以广州市轨道交通四号线南延段资讯园站—塘坑站区间为工程背景,针对其上软下硬的地层特点,运用有限元数值模拟软件Midas GTS NX建立土压平衡式盾构三维模型.对盾构隧道施工引起的横向地表沉降进行了预测,进一步采用工程实测数据和经验公式Yoshikoshi预测结果,通过对比分析以验证预测模型的可靠性.结果表明:当盾构开挖穿越复合地层时,为提高数值模拟预测结果的精度,应考虑复合地层的分层情况;模型具有较高的精确度,所输出的预测值可较好的预测实际施工中的地表沉降.所得结论对广州轨道交通及类似上软下硬地质条件下的盾构隧道施工地表沉降控制有一定参考价值.

Taking the south part of Guangzhou Metro Line 4 Zixunyuan Station to Tangkeng Station as the engineering background, considering the upper-soft and lower-hard stratum characteristics, and using the finite element numerical simulation software Midas GTS NX, an EPB shield tunneling three-dimensional model is established. The study predicts the lateral ground surface settlement induced by shield tunnel construction, and tests the feasibility and reliability of the model by comparison between the actual measured data and the empirical formula Yoshikoshi numerical simulation. The results show that in order to improve the accuracy of numerical simulation results, the stratification of complex formation should be considered when the shield is excavated through the complex formation. The model has high precision, and the predicted value of the output can be used to predict the ground surface settlement in the actual construction. The conclusion in this paper has reference value for the control of ground settlement in similar upper-soft and lower-hard soil horizon conditions. Guangzhou shield tunnel construction and other