PBA(桩-梁-拱)工法在南京地铁4号线鼓楼站古建筑保护中的应用

Application of PBA Method in the Protection of Ancient Buildings on Nanjing Metro Line 4

南京地铁4号线鼓楼站工程侧穿古建筑文物鼓楼。对鼓楼的现状进行了专业的检测及评估,确定了对古建筑本体的临时加固措施。阐述了暗挖大跨结构施工中洞法和柱洞法的适用性及选择。经分析:PBA(桩-梁-拱)工法增加了围护结构,可以支撑鼓楼建筑带来的侧向压力;其爆破开挖工程量少且初支封闭早,可减少爆破施工对地层的多次扰动;此外,其拱顶二衬结构施工较早,上部初支的暴露时间短,依靠较早形成的桩、梁及拱整体结构的可靠支撑,有利于减小地面沉降值,保证鼓楼建筑的结构稳定。施工期间对鼓楼的监测数据证实,采用PBA工法施工,变形控制较好,可有效保护古建筑安全。

The side crossing construction of Nanjing metro Line 4 at the Drum-Tower Station brings the problem of ancient building protection.Through professional detection and evaluation of the Drum-Tower conditions,contemporary reinforcement measures for the ancient building are decided.The enclosure structure added by PBA(pile,beam and arc)method will reduce the lateral pressure,the blasting excavation of it will also reduce the multiple disturbances on the ground caused by traditional blasting construction,reduce the land subsidence with the support of an integrated pile,beam and arc structure,thus ensuring the structural stability of the ancient building.By using the actual monitoring data,it is clear that the PBA method has good performance of deformation control and will protect the ancient buildings effectively.