长距离叠落盾构隧道施工对#br# 已成型隧道影响及控制措施研究

受隧道侧上方苏州桥的桥桩位置限制，北京地铁16号线万寿寺站～苏州桥站区间盾构隧道左右线呈叠落型式布置，叠落段长度为1km，隧道竖向间距1.6～4.0m，上层盾构隧道掘进将会对下层已成型隧道结构产生不利影响。针对不同的叠落段，建立了相应的计算模型，采用三维数值模拟方法分析了上层盾构隧道开挖对周围地层及下层已建成盾构隧道结构变形的影响规律，提出了下层隧道的保护措施，即：对隧道之间的土体进行注浆加固，并在上层隧道穿越下层隧道之前，对下层隧道采用型钢支撑进行加固，研发了型钢支撑结构体系及配套的安装台车。型钢支撑体系受力测试结果表明：对下层隧道结构的保护措施效果显著。

The influence of long distance overlapping shield tunnel #br# construction on the formed tunnel and appropriate countermeasures

Limited by the pile position of suzhou bridge on the upper side of the tunnels, the left and right lines of the shield tunnel between Wanshousi station and Suzhou bridge station of Beijing metro line 16 are arranged in overlapping pattern. The length of the overlapping section is 1km and the vertical spacing of the tunnel is only 1.6～4.0m. The construction of the upper shield tunnel will have a negative effect on the safety of the lower formed tunnel structure. The corresponding computational models were established for different overlapping segments, the influence of the excavation of upper shield tunnel on the deformation of the surrounding strata and the lower shield tunnel was analyzed by using 3D numerical simulation method, and the protection measures of the lower formed tunnel were put forward, that was, grouting was used to reinforce the soil between the two tunnels, and steel support was used to reinforce the lower tunnel before the upper tunnel passes through the lower tunnel, the steel support structure system and the supporting installation trolley were developed. The monitoring results of the steel support system show that the protective measures for the lower tunnel structure are effective.