In a significant advancement for urban rail transit construction, researchers have delved into the complexities of shield tunneling, particularly in proximity to critical structures such as bridges and high-rise buildings. The recent study, led by CHONG Jixin from the Jinan Rail Transit Group Co., Ltd., highlights the intricate balance between modern infrastructure development and the preservation of existing structures.
The research focuses on the Jinan Metro Line 2, where the tunnel between Shengchanlu Station and Lihuanglu Station runs alarmingly close to the pile foundations of an elevated bridge and the Eurasia Electronics Building complex. This proximity raises concerns about the potential for structural disturbances during the shield tunneling process. “To ensure the smooth implementation of shield tunneling and the safety of existing structures, understanding the structural response mechanism is essential,” said CHONG Jixin, emphasizing the need for comprehensive analysis in urban construction projects.
Utilizing finite element simulations, the study meticulously examined the deformation of adjacent structures before and after reinforcement during the tunneling process. The findings reveal that when the construction interval between the left and right lines is less than 200 rings, the cumulative disturbance could lead to significant structural deformation. This insight is crucial for construction managers and engineers, as it underscores the importance of monitoring and controlling the impact of tunneling activities on nearby infrastructure.
One of the standout solutions proposed is the implementation of secondary grouting reinforcement within a 3-meter radius of the tunnel. This technique effectively reduces the negative bending moments in building floor slabs and columns, achieving a remarkable 45.01% decrease. Such measures not only mitigate potential structural damage but also ensure that soil and pile foundation deformations remain within acceptable limits during construction. “Secondary grouting can effectively mitigate the stratum disturbance effects caused by shield tunneling,” Jixin noted, reinforcing the value of proactive engineering solutions.
The implications of this research extend beyond the immediate project at hand. As urban areas continue to expand and the demand for efficient public transport systems grows, the ability to safely conduct tunneling operations near existing structures will be paramount. This study serves as a blueprint for future urban construction projects, providing critical insights that can enhance safety protocols and construction methodologies.
As cities evolve, the construction sector must adapt to these challenges. The findings from this research, published in ‘Chengshi guidao jiaotong yanjiu’ (Urban Traffic Research), could pave the way for new standards in shield tunneling practices, ultimately fostering safer and more resilient urban environments. For those interested in further exploring this research, more information can be found through the Jinan Rail Transit Group Co., Ltd..
