Papers by Author: Wen Xin Zuo

Abstract: The saturated and unsaturated soil were widely studied by many researchers nowadays. With the development of calculation mechanics and computer, the discrete element method (DEM), as a powerful technique, has been implemented in saturated soil mechanics. This paper review the development of DEM and its application in saturated soil research. Meanwhile, it also prospect the application of DEM in unsaturated soil research. Besides, it also raised some problems that might be met in the real practice and it also tried to put forward some reasonable methods to solve these problems. In the end, this paper put forward a new DEM contact model based on the surface energy to analysis unsaturated soil.

Abstract: As a quick, accurate and efficient inspecting equipment, the Portable Falling Weight Deflectometer (PFWD) is widely used in subgrade modulus evaluation in the foreign countries. However, most analysis methods used in the modulus back calculation of PFWD is based on the classical Boussinesq solution or empirical formulas, which could hardly reflect the resilient of subgrade accurately. In this paper, the elastic half-space theory is introduced into the analysis of modulus back calculation, and with the integral transform and the numerical analysis, this paper provides an approximate method to evaluate the elastic modulus of subgrade.

Abstract: Based on extended finite element coupled with field variable method, fatigue damage numerical test of three point-bending beam with initial notch has been made to predict crack propagation path, numerical results showed : under the fatigue loading with 200Hz, and amplitude is 20KN, length of crack expanding was the biggest and crack grew as some angles with the initial crack during the first loading, crack propagated parallel to the initial angle during the other loading cycle. These results can fit the experiment very well. Using Fortran, A new user subroutine named USDFILD (User subroutine to redefine field variables at a material point) was also provided on the platform of ABAQUS, which can modal the change of physic material with time. This user subroutine can also import fatigue characterize of material into the model.