紧邻地铁设施深基坑信息化施工与分析

Information construction and analysis of deep foundation pit near subway facilities

为确保广州宏城广场基坑施工安全,考虑在地铁APM线隧道两侧由于不平衡开挖对地铁APM线隧道产生的偏压影响,在地铁隧道上方采用分区分层分段逐步开挖的方式开挖基坑,同时依据不同的地质条件和开挖深度采用水泥土墙+内支撑、搅拌桩+钻孔灌注桩+锚索、搅拌桩+钻孔灌注桩+内支撑、搅拌桩+地下连续墙+内支撑、旋喷桩+旋挖桩+内支撑(斜撑)等多种综合支护方案。通过详细的监测方案了解基坑支护结构的变形情况以确保基坑安全。监测数据表明:锚索拉力和基坑的水平位移主要发生在基坑土体的开挖阶段,基坑土体的平衡开挖较好地控制了地铁隧道的变形,周边的建筑物、道路和管线的变形也较小。

In order to ensure the safety of foundation pit construction of Guangzhou Hongcheng Plaza, considering the eccentric earth pressure on subway APM line due to unbalance excavation on both sides of subway APM line, the piecewise and block excavation method above the subway tunnel was favorable for excavating the foundation pit. Based on different geological conditions and foundation pit depth, the cement soil wall with interior supports,mixing pile with bored piles and anchor cables, mixing pile with bored piles and interior supports, mixing pile with diaphragm walls and interior supports, rotary churning piles and rotary drilling piles with interior supports（ diagonal braces）were combined to form the supporting scheme of Guangzhou Hongcheng Plaza foundation pit construction. A detailed monitoring scheme was laid to find out the deformation conditions of the supporting system of the deep foundation pit to ensure the safety. The monitoring data indicate that tension force of the anchor and horizontal displacement of foundation pits mainly take place in excavation stage of the foundation pit. The balance excavation of the foundation earth well controls the deformations of the APM line, surrounding buildings, roads and underground pipelines.