城市浅埋隧道埋深对地面沉降的影响规律

Influence Law of Urban Shallow-buried Tunnel Buried Depth on Land Subsidence

[目的]隧道埋深是隧道施工引起地面沉降的重要因素之一,特别是在城市地下空间施工过程中,细微的环境变化极易产生安全隐患。因此,有必要研究城市浅埋隧道的埋深对地面沉降的影响规律。[方法]提出一种关于隧道半径与埋深比的地面沉降理论解二维修正模型;以重庆地区某在建隧道为例,通过模型试验,分析不同埋深条件下地面沉降的变形规律,验证所提修正模型对地面沉降预测的合理性与可行性。[结果及结论]随着隧道埋深的增加,地面沉降总体呈下降趋势,沉降槽的宽度逐渐增大,隧道轴线上的最大沉降量逐渐减小;相较于原理论解及Peck公式解,修正后的沉降预测模型与试验值所得曲线较为接近,且修正模型在不同隧道埋深条件下具有更好的适用性;在浅埋隧道施工过程中,当隧道埋深增加时,建议扩大控制保护区的范围。

[Objective]The buried depth of tunnel is one of the important factors contributing to land subsidence induced by tunnel construction,especially in urban underground space where subtle environmental changes are prone to cause safety hazards.Therefore,it is necessary to investigate the influence law of urban shallow-buried tunnel buried depth on land subsidence.[Method]A two-dimensional modified model is proposed,regarding the ratio of tunnel radius to buried depth for land subsidence theoretical solution.Taking a tunnel under construction in Chongqing as example,with model tests,the deformation law of land subsidence under different buried depth conditions is analyzed,and the rationality and feasibility of the proposed modified model are verified in predicting land subsidence.[Result&Conclusion]With an increase in tunnel buried depth,the overall trend of land subsidence decreases,and the width of subsidence trough increases gradually,while the maximum subsidence amount along the tunnel axis decreases gradually.Compared to the original theoretical solution and Peck′s formula solution,the modified subsidence prediction model aligns closer with the curves obtained from tests.Moreover,the modified model demonstrates better applicability under different tunnel buried depth conditions.During the construction of shallow-buried tunnel,it is recommended to expand the scope of control protection zone as tunnel buried depth increases.