高速铁路明挖隧道基底预留沉降量研究

Study on Reserved Settlement of Foundation of Open-cut Tunnel in High Speed Railway

高速铁路明挖隧道基底通常要进行碎石换填。本文依托新建京张高速铁路东花园隧道,采用现场监测和理论计算,对高速铁路明挖隧道基底的预留沉降量进行分析。结果表明:明挖隧道结构沉降量的分布与土方回填厚度一致;隧底沉降量与附加应力在水平和竖直方向上的传递规律一致;基底变形简化计算深度与现场实测的沉降量较吻合。提出了高速铁路明挖隧道基底预留沉降量的估算公式。实际观测表明6个月时沉降才逐渐趋于稳定。建议类似高速铁路明挖隧道结构的沉降观测期至少为6个月。

Based on the high speed railway open-cut tunnel base only the gravel replacement is carried out.Based on the new Beijing-Zhangjiakou high speed railway east garden tunnel,this paper analyzes and discusses the reserved settlement of the high speed railway open-cut tunnel base by on-site monitoring and theoretical calculation.The analysis shows that the distribution of the settlement of the open-cut tunnel structure is consistent with the thickness of the earth backfilling volume.The settlement at the tunnel base corresponds to the distribution of additional stress in horizontal and vertical direction.The calculated depth of the simplified deformation of the tunnel base is in line with the measured settlement in the field.Finally,through the theoretical calculation and field measurement comparison analysis,an estimation formula for the reserved settlement of the high speed railway open-cut tunnel base is proposed.The settlement observation time gradually stabilizes when it reaches 6 months.Thus,the settlement observation period is suggested more than 6 months for the similar high speed railway open-cut tunnels.