## 5 Conclusions  
The near-range underpass of the shield tunnel has a significant influence on buildings, which might lead to considerable disturbances on the ground and significant displacement of the segments and buildings. This paper focuses on the slurry-shield tunneling construction under-passing the pedestrian culvert of the North Ring Road at the upper-soft, lower-hard composite strata in the Tongdewei-Shangbu section of the northern extension of Guangzhou Metro Line 8. The influences of the MJS method on ground subsidence, displacement of segments, bridges, and culverts, as well as the control of inner stress using field monitoring and numerical simulation analysis, were evaluated. The main conclusions are as follows.  
1. After the construction of the left tunnel, when the soft-rock height ratio was 1.0, the surface attained the maximum subsidence value of 7.97 mm, showing that the ground subsidence value was in a safe range. However, when the soft-rock height ratios of the adjacent excavation faces ranged from 0 to 0.2 and from 0.5 to 1 special attention was given to the differential ground subsidence that might be generated in the subsequent shield construction.  
2. The concentrated release of stress might occur at the beginning and end stages of the shield construction underneath, which has a greater impact on the structure than the geological conditions of the shield-tunneling face. Hence, ground subsidence at the beginning and ending stages needs more concern, even if the shield tunnel is under-passing the building under favorable geological conditions.  
3. Reinforcing with the MJS method could effectively control the concentrated release of stress that may be caused by the shield-tunneling project. Moreover, it not only reduces the disturbance to the preceding tunnel during the excavation of the double-line tunnel, but also minimizes the pressure loss of the tunnel's surrounding rock and the maximum displacement of the adjacent segments caused by the shield excavation. Thus, the safety of tunneling projects can be enhanced.  
4. The displacement of the pile foundation in the under-passing project was reduced by more than 80% based on reinforcement using the MJS method. Moreover, no additional bending moment was applied to the pile foundation, indicating that the strength of the MJS reinforcement body can be lowered to reduce the construction cost in practice.  
5. The ground subsidence of the left tunnel vault was 5.30 mm in the numerical simulation, which was consistent with that of the newly built tunnel vault of the monitoring section at a soft-rock height ratio of 0.5 in field monitoring. This proves the effectiveness of the numerical simulations conducted in this study.  
Conceptualization, J.L.; Formal analysis, [PERSON] ([PERSON]) and X.X.; Funding acquisition, J.L.; Investigation, [PERSON] ([PERSON]) and J.H.; Project administration, [PERSON] ([PERSON]); Supervision, H.F.; Writing--original draft, [PERSON] ([PERSON]); Writing--review & editing, J.L. All authors have read and agreed to the published version of the manuscript.  
This paper is supported by The Guangdong Provincial Natural Science Foundation of China: (Project No. 2019A1515011397).  
Not applicable.  
The authors declare no conflict of interest.