地铁18号线江浦路站大断面冻结暗挖施工监测技术研究

Research on Monitoring Technology of Large Cross-Section Freezing Underground Excavation for Jiangpu Road Station in Metro Line 18

摘要:

上海轨道交通18号线江浦路站采用冻结法结合高压旋喷注浆加固（metro jet system， MJS）、管棚、开挖面全断面注浆和矿山暗挖技术进行施工。工程分2段暗挖法施工，具有超大断面（暗挖段南侧长度15.899 m×宽23.0 m×高12.4 m，北侧长度10.101 m×宽22.8 m×高13.7 m）、超浅覆土（顶板覆土约2.476 m）、复杂环境等技术特点。通过对江浦路站地表沉降、围护结构变形、土体温度场、管线变形等关键参数的实时监测，获得了大量监测数据。研究结果表明：南井施工期间MJS加固阶段监测点地表日均变化量为0.8 mm，冻结阶段为1.2 mm；北井施工期间地表日均变化量为1.1～1.3 mm，3期冻结后隆起速率增大1倍；冻结28 d后土体温度稳定在-10 ℃以下，冻结壁厚度达905 mm；?500、?300燃气管线最大差异沉降分别达142.5、133.2 mm，均通过工程措施得到有效控制。该工程为全国首例大断面超浅埋地铁车站整体冻结暗挖工程，成功实现了城市中心区域地下管线“零”迁移和繁忙交通“零”干扰，标志着我国在复杂环境下大断面冻结暗挖施工技术达到国际先进水平。

Abstract:

Jiangpu Road Station in Shanghai Metro Line 18 is constructed by using the freezing method combined with high-pressure rotary jet grouting reinforcement (metro jet system, MJS), pipe shed, full-section grouting of the excavation face and mine underground excavation technology. This project is divided into two sections for underground excavation, which has the technical characteristics of ultra-large section (the length at the south side of the underground excavation section is 15.899 m long × 23.0 m wide × 12.4 m high, and at the north side is 10.101 m long × 22.8 m wide × 13.7 m high), ultra-shallow soil cover (about 2.476 m on the roof), and complex environment. By real-time monitoring of key parameters such as surface subsidence, deformation of retaining structures, soil temperature field and pipeline deformation of Jiangpu Road Station, a large amount of monitoring data has been obtained. The research results show that during the MJS reinforcement stage in the construction of the south shaft, the average daily variation of the surface at the monitoring point is 0.8mm, and during the freezing stage, is 1.2 mm. During the construction of the north shaft, the average daily change of the surface is 1.1 ~1.3 mm, and the uplift rate doubles after the third stage of freezing. After 28 days of freezing, the soil temperature is stabilized below -10 ℃, and the frozen wall thickness reaches 905 mm. The maximum differential settlement of the ?500 and ?300 gas pipelines reach 142.5 mm and 133.2 mm, respectively, which are effectively controlled through engineering measures. This project is the first integral freezing underground excavation project of large-section ultra-shallow embedded metro station in China, which has successfully achieved the "zero" removal of underground pipelines and "zero" interference of busy traffic in the central area of the city, marking that the large-section freezing underground excavation construction technology in complex environments has reached the international advanced level in China.