Research On Constitutive Model And Numerical Simulation Of Water-bearing Fractured Rock-mass

In recent decades,scholars at home and abroad have done a great quantity researches on water-bearing fractured rock-mass,which have a certain breadth and depth.But in summary the researches were mainly concentrative on the derivation of theoretical formula.In the aspect of numerical simulation,a majority of scholars use the Mohr-colomb model to simulate,analyze and contrast.There is no substantial developed constitutive model which is consistent with the theoretical research and applied to the actual project.Therefore,based on the above research background,this paper makes reference to the elastic-plastic mechanics,damage mechanics,rock mechanics,continuum theory and other discipline knowledge and basic theory.A new constitutive model of FLAC3 D is developed by using Microsoft Visual Studio 2010 program,which is based on the non penetrating and closed fracture of water-bearing fractured rock-mass.The main research work and innovation achievements are as following:(1)Getting the stress-strain relationship of the modified constitutive model of water-bearing fractured rock-mass by modifying the flexibility tensor C of Mohr-colomb model,which considers the influence of initial osmotic pressure P,initial damage,extension and destruction of the fracture,multiple stochastic fracture and so on.(2)A constitutive model for one single water-bearing fractured rock mass is developed by using the secondary development module of FLAC3 D and Microsoft Visual Studio 2010 program.Then through building a 25m*25m*1m circular tunnel model,we verify the accuracy and applicability of the new constitutive model.(3)Under successfully simulating the random fissures network of water-bearing fractured rock-mass by MATLAB,we make a comprehensive analysis of the influence of multiple stochastic fracture to the newly developed model theory and got the suitable range by using the same secondary development method.The simulation results show that the more the random cracks are distributed.the more deformation of the model is.When the distribution of random cracks is in a certain range,the newly developed model theory is efficient,but be failure over a certain range,and simulation results is inaccurate.It reflects the limitations of this theory.(4)Within the scope of this theory of the secondary development,combined with the newly developed constitutive model,we select a shield tunnel excavation engineering to simulate and get some conclusions about the displacement field of water-bearing fractured rock-mass,which can provide some reference value for the later design of tunnel support.