Search

An algorithm for arbitrary polygonal aggregate generation is proposed based on secondary development of ANSYS in this paper. It is established on the basis of circular aggregate model, and the central angle is the control parameter to generate poristic polygon as the coarse aggregate of concrete. The concrete numerical samples with first gradation of aggregate and two gradation of aggregate are generated. The aggregate fraction of polygon sample is lower about 20% than the original circular aggregate sample in the statistical sense. The results show that the proposed method can simulate gravel aggregate appropriately as long as the central angle and the aggregate percentage of original circular aggregate sample is reasonable controlled.

To establish an appropriate random aggregate model at meso-level is the basis for successfully simulating the meso-mechanical behaviors of concrete. This paper proposes a new simple method to generate random aggregates of concrete by PFC2d. And the distribution of aggregate in the two-dimensional concrete specimen cross-section is determined by Walraven formula. The results show that the numerical aggregate distribution matches well with the theoretical grading curve.

In order to simulate the seepage field with drain pipes, the air element method is used in this paper. In this method, the pipe elements are regarded as a kind of material with high permeability coefficient and an equivalent hydraulic conductivity is assigned to them. Thus these pipe elements can be included in the conventional seepage calculation as other common elements. Moreover, the difficulty of giving water head boundary to the inner surface of pipes directly is avoided. According to the seepage calculation of the channel with large number of drain pipes in Huangyou part of the middle line in South-to-North water transfer project, the results show that, with drainage-piping, the pore water pressure in channel foundation is reduced significantly.