软土地区顶管下穿既有收费站施工影响及现场监测

Construction Impact and On-site Monitoring of Pipe Jacking Underpassing the Existing Toll Station in Soft Soil Area

地下管道施工会引起地层扰动,影响近接既有结构。文章结合现场监测情况,建立数值模型,对广州南沙自贸试验区合兴变电站至灵新大道段电力隧道施工进行模拟分析,研究顶管掘进过程中顶进区段内地表及收费站房变形情况及其受力特点。结果表明:地表最大沉降为18.3mm,收费站最大隆起为4.5mm,土体最大应力为1684kPa,桩体受力最不利位置在近顶管顶进段一侧顶部。通过对比监测数据与数值模拟结果,实测值略大于模拟值,但整体变化趋势一致,模拟结果较为可靠,也证明了下穿既有建筑物顶管施工控制地表及建筑物稳定性的有效性。

The construction of underground pipelines will cause stratum disturbance and affect the existing structure.In combination with the on-site monitoring situation,the construction of the power tunnel from Hexing substation to Lingxin avenue section in Nansha pilot free trade zone of Guangzhou is simulated and analyzed by establishing the numerical model,and the deformation and stress characteristics of the ground surface and toll station house in the jacking section during the pipe jacking tunneling process are studied.The results show that:the maximum ground surface settlement is 18.3mm,the maximum uplift of the toll station is 4.5mm,the maximum soil stress is 1684kPa,and the most unfavorable position of the pile body is at the top of the side near the jacking section of the pipe jacking.By comparing the monitoring data with the numerical simulation result,the measured value is slightly larger than the simulated value,but the overall change trend is consistent,and the simulation result is more reliable,which also proves the effectiveness of the pipe jacking construction control underpassing the existing building on the ground surface and the stability of the building.