Evolution laws of internal forces in rectangular pipe jacking tunnels with large section and shallow soil

The monitoring technology for underground engineering during construction period is relatively mature, but there are few researches on the evolution laws of internal forces in pipe jacking tunnels. The results of the previous researches show that: (1) The tunnel is not directly affected by the earth pressure, and the grouting pressure plays a controlling role. (2) The longitudinal reinforcement stress is related to the internal forces of the pipe, and it shows different mechanical properties at different locations. (3) The circular reinforcement stress is affected by many factors, but the stress level is generally not high. These conclusions are mainly based on the theoretical analysis but lack of the measured data. Moreover, the stress level of a structure is affected by a range of factors such as buried depth, and the evolution laws of the internal forces should depend on the specific in-situ conditions. On the basis of the monitoring data from the pipe jacking tunnel of Luxiang Road-Qilianshan Road, the above conclusions are compared and modified, and the evolution laws of the internal forces in rectangular pipe jacking tunnel under shallow soil during construction period are put forward.