超深斜交换乘地铁车站基坑开挖施工技术分析及效果评价

Analysis and Effect Evaluation of Excavation Construction Technology for Foundation Pit of Ultra Deep Skew Interchange Subway Stations

为保证超深斜交换乘地铁车站基坑的顺利施工,基于项目区地质条件,先从支护设计、施工方案及施工技术三方面开展基坑开挖技术分析,再结合现场监测成果,开展基坑施工后的效果评价.分析结果表明:项目区地层岩性相对较差,加之两条地铁线斜交,工程复杂性较强,因此,开展基坑开挖施工技术分析是十分必要的.同时,在工后效果评价结果中,累计变形值介于12.57 mm~26.09 mm,平均值为19.19 mm,均小于预警值(30 mm),说明在现有条件下,基坑开挖施工效果较优,达到了控制效果,且经变形预测,基坑变形虽还具较小增加幅度,但最终预测值均在预警值范围内.因此,在预测条件下,基坑开挖施工效果也较优,充分验证了基坑开挖施工技术的合理性,可为类似工程提供经验支持.

To ensure the smooth construction of the foundation pit of the ultra deep skew interchange subway stations,based on the geological conditions of the project area,the excavation technology analysis of the foundation pit was carried out from three aspects including support design,construction plan and construction technology.Then,in combination with on-site monitoring results,the effect evaluation of the foundation pit construction was performed.The analysis results indicated that the geological lithology of the project area was relatively poor,and coupled with the oblique intersection of two subway lines,the engineering complexity was strong.Therefore,it is necessary to conduct technical analysis of foundation pit excavation construction.Meanwhile,in the post construction effect evaluation results,the cumulative deformation value rangeed from 12.57 mm to 26.09 mm,with an average value of 19.19 mm,which was less than that of the warning value(30mm).This indicated that under existing conditions,the excavation construction effect of the foundation pit was relatively good,achieving control effect.Moreover,through deformation prediction,although the deformation of the foundation pit still had a small increase,the final predicted values were all within the warning value range.Therefore,under the predicted conditions,the excavation construction effect of the foundation pit was also relatively good.Fully verified the rationality of foundation pit excavation construction technology and accumulated experience for similar projects.