高寒地区地铁隧道沉降规律研究

Settlement of Tunnel Excavations in Cold Regions

以哈尔滨地铁3号线湘会暗挖区间右线隧道施工监测为背景,通过对地铁施工过程中地表沉降监测点和拱顶沉降监测点累计沉降值的分析,总结哈尔滨地铁在隧道开挖过程中地表沉降和拱顶沉降的变化规律。发现隧道开挖过程中纵向地表沉降主要发生在上台阶掌子面通过监测断面前1.6 B(B为洞宽)到通过监测断面后4.8 B范围内,并对比冻融对地表沉降造成的影响;横向地表沉降主要发生在距隧道中心线两侧3.2B范围内,给出横向地表沉降数学表达式并计算出沉降槽宽度参数建议值为k=0.78,其结果与实测结果吻合较好;隧道内拱顶沉降主要发生在上台阶掌子面通过监测点前1.6 B到通过监测点后3.2 B范围内;隧道内初期支护体系的设置对控制拱顶沉降有明显作用。

The research background of this study involves the monitoring of the construction of the excavation section from the Xiangjiang Road Station to the Convention and Exhibition Center Station of Harbin Metro Line 3.Through the analysis of the accumulated value of the surface settlement and vault settlement during the construction of the subway,the change law of the settlement of the ground and vault during the tunnel excavation in Harbin Metro was summarized.The results of this research are as follows:Longitudinal ground settlement mainly occurred in the range of the working face through to the monitoring section 1.6 B (B represents excavation width)ahead to section 4.8 B behind the monitoring section.The effect of thawing on the surface subsidence was compared;the transverse ground settlement mainly occurred in the 3.2 B range between the two sides of the central line of the tunnel.The mathematical expression of the transverse ground settlement was obtained and the recommended value of the width parameter of the settlement trough was calculated at k =0.78.It was noted that these results are in good agreement with the measured ones;the tunnel vault settlement mainly occurred in the range of working face through the monitoring point 1.6 B ahead to the 3.2 B behind the monitoring point.Further,the setting of the initial supporting system in the tunnel had an obvious effect on controlling the settlement of the vault.