Abstract:The change rule of the longitudinal force between the rings of shield tunnel is especially important for the design and analysis of the water stop pad between the segment rings, but it is difficult to measure the longitudinal force between the rings due to the limitation of the monitoring method. Taking the new project of Nanjing Jiangxinzhou Sewage Collection System Channel II （crossing the Sandwich River section) as the engineering background, the pre-buried sensors in the inter-ring monitor the trend of longitudinal force change in the repeated assembling tunneling process of the end face of the concrete segments from the contact to the jack loading and then to the unloading， and the longitudinal force formula is deduced for calculation. The conclusions are that the longitudinal force between the segments and rings will change with the jacking and withdrawal of jacks during the shield tunneling and assembly stages. The values range from 0 to 10 MPa. The measured longitudinal force value is slightly less than the PLC data in the segment tunneling stage after the monitoring ring 3. The ratio is around 0.8. The measured value of inter-ring pressure in the assembly stage is generally smaller than the PLC data. The ratio is fluctuating from 0.3 to 0.95. The longitudinal force between the rings is decreasing as the shield tunneling is continuous in the forward direction until the shield tunneling to the 463 ring, the residual longitudinal force between the rings is monitored at about 0.2 MPa.
