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.
Experimental study on working parameters of EPB shield machine
Due to the limitation of geologic condition and construction technology,the advance of shield machine would disturb stratum inevitably,which could induce a series of environmental problems.For better understanding the relationship between the soil working parameters of machine and the perturbation characteristics of stratum,it is necessary to start the elementary experiment researches on ground-shield machine system.Therefore,a special test scheme was designed firstly for this purpose.It included:(1) A model of earth pressure balance shield machine with diameter of 0.4 m;(2) A soil box with dimension of 2.4 m×2.4 m×1.2 m;(3) Control system of driving and rotating;(4) Computer-aided data collection system.Subsequently,in hard and soft model stratum respectively,various working parameters of machine were combined for tunneling test.Based on the test results,some useful rules were drawn.