The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sand...The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sands were reproduced and the slump test and the direct shear test of the conditioned sands were implemented. A DEM equivalent model that can simulate the macro mechanical characteristic of the conditioned sands was proposed,and the corresponding numerical models of the slump test and the shear test were established. By selecting proper DEM model parameters,the errors of the slump values between the simulation results and the test results are in the range of 10.3%-14.3%,and the error of the curves between the shear displacement and the shear stress calculated with the DEM simulation is 4.68%-16.5% compared with that of the laboratory direct shear test. This illustrates that the proposed DEM equivalent model can approximately simulate the mechanical characteristics of the conditioned sands,which provides the basis for further simulation of the interaction between the conditioned soil and the chamber pressure system of the EPB machine.展开更多
A successful simulation still requires the user to have good simulation knowledge and well developed modeling skills despite a large number of simulation software products available to users. This paper presents the d...A successful simulation still requires the user to have good simulation knowledge and well developed modeling skills despite a large number of simulation software products available to users. This paper presents the design principles and implementation of a layered modeling system known as General-Purpose user-defined Modeling System (GPMS) which provides the user with multiple accesses to build a simulation model at three different levels of knowledge and skills. It does this by purpose-designed GPMS simulation language, which is briefly described in this paper.展开更多
基金Project (2007CB714006) supported by the National Basic Research Program of China
文摘The discrete element method (DEM) was used to simulate the flow characteristic and strength characteristic of the conditioned sands in the earth pressure balance (EPB) tunneling. In the laboratory the conditioned sands were reproduced and the slump test and the direct shear test of the conditioned sands were implemented. A DEM equivalent model that can simulate the macro mechanical characteristic of the conditioned sands was proposed,and the corresponding numerical models of the slump test and the shear test were established. By selecting proper DEM model parameters,the errors of the slump values between the simulation results and the test results are in the range of 10.3%-14.3%,and the error of the curves between the shear displacement and the shear stress calculated with the DEM simulation is 4.68%-16.5% compared with that of the laboratory direct shear test. This illustrates that the proposed DEM equivalent model can approximately simulate the mechanical characteristics of the conditioned sands,which provides the basis for further simulation of the interaction between the conditioned soil and the chamber pressure system of the EPB machine.
文摘A successful simulation still requires the user to have good simulation knowledge and well developed modeling skills despite a large number of simulation software products available to users. This paper presents the design principles and implementation of a layered modeling system known as General-Purpose user-defined Modeling System (GPMS) which provides the user with multiple accesses to build a simulation model at three different levels of knowledge and skills. It does this by purpose-designed GPMS simulation language, which is briefly described in this paper.
