###### Abstract  
As the urban underground space environment gets more complex, the cases of shield machines encountering and cutting through piles are becoming more common. The interaction between the cutter head and pile foundation directly affects the tunneling performance of the shield machine and the safety of the existing structure. To study the interaction between the pile and the shield machine, a calculation model of the interaction force is established. A field test of cutting two piles was conducted and the rationality of the model is verified by comparing the calculation results with field test data. The model is applied in the project of a shield machine cutting bridge piles in Harbin Metro Line 3, China. The shield operation parameters are predicted and compared with field test results. Besides, the impacts of cutting surface width and eccentric distance on interaction force are discussed. The study shows that there is a significant interaction between the cutter head and the piles when the shield machine cuts reinforced concrete piles, which causes obvious changes in the shield operation parameters and shield performance. The number of tools that are inside the cutting area has a significant effect on the additional torque. The additional torque fluctuates with the rotation of cutter head and increases with the increase of the number of tools. The number of these tools is determined by factors such as the layout of tools in the cutter head, cutting surface width and eccentric distance, which influence the position of each tool relative to the cutting area. As the cutting distance increase, the additional torque of the cutter head shows a trend of first increasing and then decreasing and reaches the maximum value when the cutting distance reaches the radius of the pile. Besides, the additional force and additional moment of the cutter head increase with the increase of the cutting surface width. The impacts of eccentric distance on additional force and additional moment are complicated. The results in this paper can provide reference for similar engineering. shield tunnel; obstacle pile foundation; cut through; interaction force; theoretical model +
Footnote †: journal: Applied Sciences  
In recent years, cases of shield machines directly cutting through reinforced concrete piles have appeared frequently, especially in China. In the construction of Tel Aviv Light Rail Red Line in Israel, the TBM (Tunnel Boring Machine) cut and passed through 14 reinforced concrete piles [9]. A shield tunnel crosses through group pile foundation of a road bridge with pile underpinning technologies in Shanghai, China [10]. Some other similar cases also appeared in a few cities in China, such as Guangzhou and Shenzhen. It is crucial to carry out research related to reinforced concrete pile cutting technology. At present, most studies focus on the influence of tunnel excavation on pile foundation and the influence of pile on the structure of tunnel in projects where the tunnels pass by nearby piles. A variety of papers have been conducted on this subject based on theoretical analyses [11; 12; 13; 14; 15; 16; 17], numerical approaches [18; 19; 20; 21; 22; 23] and laboratory model tests [24; 25; 26; 27; 28; 29; 30; 31; 32]. However, few studies have focused on the problem of shield machines directly cutting reinforced concrete piles. [PERSON] et al. studied a new type of polycrystalline diamond compact cutter, which is based on cutters widely used in oil drilling, to cut reinforced concrete [33]. [PERSON] investigated the behavior of piles in a large pile group and associated buildings through 3D finite element analysis and parametric studies. A field test study and the practice of cutting piles in Suzhou subway construction were conducted by [PERSON] et al. [34] and [PERSON] et al. [35]. Besides, the interaction between the cutter head and pile directly affects the tunneling performance of shield machine and little research has been done on this issue.