地下工程抬升注浆设计方法及其抬升效果预测研究

Design of displacement grouting and prediction of the effect for construction of underground structures

以北京地铁五号线崇文门地铁车站下穿既有线抬升注浆工程为研究对象,结合监测数据与三维有限差方法分析新建车站开挖引起既有线沉降的特征,以此为依据进行抬升注浆设计。通过在"注浆单元"上施加膨胀压力模拟注浆抬升既有结构的效果并与实测数据做对比,验证了施加膨胀压力模拟抬升注浆的正确性和有效性,为今后类似工程的设计提供了预测抬升效果的方法。在此基础上进一步研究得出止浆墙能有效限制土体侧向膨胀,提高抬升效果的结论。

The project was to artificially raise an existing tunnel by grouting for the construction of the Chongwenmen subway station of Beijing Metro Line 5. In situ measured data and 3-D finite difference analysis were employed to analyze the settlement features of the existing tunnel caused by excavation, and displacement grouting was designed in accordance with the settlement features. In the numerical simulations, expanding pressure was applied to the grouting elements to simulate the heaving effect of grouting on the existing tunnel. Comparing with the measured data, the numerical method is proved to be suitable, and can be used to predict the effect of displacement grouting for similar projects. It is concluded that the grouting-proof curtain was effective in limiting lateral soil expansion and in enhancing the effect of displacement grouting.