盾构隧道穿越火车站股道风险分析及对策

以昆明市轨道交通首期工程环城南路站~昆明火车站站盾构区间隧道为背景,采用专家分析法和数值模拟法对其下穿昆明火车站股道的施工风险进行综合分析,并提出相应对策。结果表明,盾构隧道下穿股道时,股道的差异沉降和纵向不均匀沉降风险等级为极高,且股道纵向沉降在L=10 m弦量测的最大矢度值达到5.13 mm,股道间的差异沉降最大值4.13 mm,均超过4 mm的控制要求,需要采取纵向轨束梁吊轨加固、土体改良、优化盾构参数等一系列措施加以控制,以确保昆明火车站的运营安全。研究成果可应用于本工程的设计与施工,同时也可为将来其它类似工程提供借鉴,具有进一步推广的可能。

Analysis and Measures for Risk of Metro Shield Tunneling Crossing underneath Tracks of Railway Station

With the rapid development of urban mass transit system, more and more attentions are paid to the risks of the shield tunnel crossing underneath the railways, because the ground settlement caused by tunnel construction process may likely influence the operation security of railways. This work is based on the shield zone tunnel of Phase 1 of Kunming urban mass transit crossing underneath the railways of Kunming Station, the expert analysis method and numerical simulation method were carried out to study the construction risk, and corresponding measures are provided simultaneously. Expert analysis indicates that the risk ratings of differential settlement of the steel rails and the longitudinal asymmetric settlement are both very large. Furthermore, numerical simulation also demonstrates that the longitudinal settlement reaches 5.13 mm, and the maximum differential settlement of the steel rails is 4.13 mm. The two both didn’t satisfy the requirements of less than 4 mm. Consequently, a series of measures such as longitudinal reinforced beam, soil improvement, shield parameters optimization, and so on,were taken to ensure the operation security of Kunming Station during the construction of shield tunnel. Although expert analysis method and numerical simulation method have their advantages and disadvantages, it is an effective approach to combine these two methods to solve the problems of the shield tunnel crossing underneath the railways. The research results can be applied to the process of construction of this or other similar projects, and the method proposed in paper may get extensive application in engineering.