Research on 3d elastoplastic numerical analysis of settlement joint of shield tunnel based on the interaction between soil and structure
Considering the effect on uneven settlement of tunnel longitudinal stratum, a 3d elastoplastic numerical model is established for the arrangement of settlement joint and the calculation of force and deformation of tunnel longitudinal structure based on the interaction between soil and structure. In the FEM calculation model, soil material is elastoplastic, the soil constitutive model selected Mohr Coulomb, the element type of soil choose a three-dimensional solid element, the element type of segment structure use space shell element, and settlement joint use three-dimensional linear elastic spring. Calculation shows that, this calculation model is able to fully consider the impact of tunnel the uneven settlement of all factors, and may better simulate the vertical force and deformation behavior of tunnel structure in complex ground formation conditions. Research conclusion gives the vertical force and deformation of the tunnel structure under the condition of different set of settlement joint, and has an important reference value for the future design and construction of the tunnel lining structure.
Numerical Study on the Effect of Grouting on Long-Term Settlement of Tunnels in Clay
The long-term settlements over tunnels can be rather significant, particularly when tunnels are embedded in soft and compressible soils. The influence of grouting on the evolution of long-term surface settlement, as well as ground loss, is simulated by imposing prescribed volumetric strain on the disturbed area around the tunnel due to shield tunneling. The volumetric strain could be detected from the grouting ratio of grouting volume and the volume of the physical gap of shield tunnel. Finally, some conclusions are drawn from the numerical simulations.
SIMILARITY FORMULAE OF MODEL TESTING IN ADVANCING SHIELD TUNNELS
The similarity formulae of model testing in advancing shield tunnels are proposed based on the Goodierian theory. Many practical factors such as the advancing pressure and speed, the soil pressure, the soil discharging and losing ratio, and the infused mud quantities are included in them. The viscosity-elasticity-plasticity property as well as the large deformation of the soft soil are considered in the discussion. The formulae can be used to design the testing model and to process the testing data.