Abstract:
The risk of the adjacent construction of overlapped shield tunnel with a small radius of curve is relatively high, so its safety control is of great importance in the industry. Based on the case of an overlapped shield tunnel project, the feasibility of control measures such as interlayer soil grouting, erection of internal steel supports, etc.was studied through numerical simulation, and a reasonable control scheme was proposed accordingly. In addition,the effect of safety control was evaluated according to the data of on-site monitoring. The study results showed that,compared with the scheme without reinforcement measures, the reinforcement through interlayer soil grouting could increase the strength of interlayer soil and effectively reduce the floating of segments, while the erection of internal steel supports were could reduce the horizontal deformation of segments. The combination of these two schemes could effectively maintain the shape of the section, and the maximum values of vertical deformation of segment crown and convergence deformation of horizontal clearance were 7.02 mm and 2.74 mm respectively, both of which were less than the standard value of deformation control. Therefore, the combined use of interlayer soil grouting and erection of internal steel supports on site was reasonable and feasible.