为研究高铁隧道悬臂掘进机法施工过程中机场区地表沉降变化特征，以渝昆高铁下穿长水机场隧道工程为例，结合隧道下穿机场区地表位移的实时自动监测数据，深入分析悬臂掘进机法施工引起的机场区地表横向和纵向沉降规律。结果表明： 1）地表沉降时程变化整体表现为平稳波动、快速发展、趋于稳定3个阶段，地表沉降的快速增加主要集中在上台阶通过监测点后至下台阶通过监测点前的时间段内； 2）修正Peck公式能较好地表征悬臂掘进机施工引起的地表横向沉降分布特征，地表最终沉降为7.3~25.0 mm，地层损失率为0.16%~1.01%，横向影响范围为4.0D~5.3D（D为隧道开挖跨度），最不利区域集中在隧道两侧各1.3D，需重点监测； 3）受上侧既有机场货运通道斜交、隐伏溶洞以及岩石产状等不均匀地质条件的影响，部分断面的地表沉降槽分布整体向右侧偏移； 4）不同开挖阶段引起的地层损失及地表沉降量有明显差异，上、下台阶和仰拱开挖阶段引起的地层损失率依次减小，引起的地表沉降量分别占总沉降的81.3%、17.0%和1.7%； 5）纵向沉降规律表明，地表纵向最终沉降曲线呈现先增大后减小的变化趋势，隧道开挖引起的地表沉降纵向影响范围为3.2D~6.0D，具体表现为开挖面前方1.3D~2.3D和后方1.4D~3.9D。
In this study, a case study
is conducted on the Chongqing-Kunming
high-speed railway crossing underneath the Changshui
airport, and the automatically monitored data in real-time
of the airport surface displacement are used to analyze the lateral and
longitudinal settlement patterns of the surface caused by the construction of
the cantilever boring machine method. The results show the following: (1) The
overall temporal evolution of surface settlement manifests in three distinct
phases: gradual fluctuation, accelerated development, and stabilization. The
rapid development of surface settlement concentrates in the interval after the
upper bench passes through the monitoring point and before the lower bench
passes through the monitoring point. (2) The modified Peck′s formula is more effective in characterizing the distribution of
lateral surface settlement caused by the cantilever boring machine
construction. The final settlement of the surface is 7.3 to 25.0 mm, the strata
loss ratio is in the range of 0.16% to 1.01%, the lateral impact range is 4.0D to 5.3D (D is the span of the tunnel excavation),
with the most unfavorable area concentrated in the range of 1.3D on either
side of the tunnel, where requires particular monitoring. (3) The unfavorable
conditions, including the diagonal intersection of the upper existing airport
cargo access road, hidden cavities, and rock production, result in a shift in
the distribution of surface settlement troughs in some sections to the right.
(4) A notable discrepancy is observed in the extent of strata loss and surface
settlement attributable to the various excavation phases, the strata loss rate
associated with the excavation stages of upper and lower benches, as well as
the invert arch, exhibits a descending order, with the respective proportions
accounting for 81.3%, 17.0%, and 1.7% of the total settlement. (5) The
longitudinal settlement pattern demonstrates that the longitudinal final
settlement curve of the surface exhibits a pattern of increase initially and
then decrease. The longitudinal influence of surface settlement resulting from
tunnel excavation ranges from 3.2D to6.0D, with a
corresponding variation of 1.3D to 2.3D ahead of the excavation and 1.4D to 3.9D behind.
