Construction of a 3D meso-structure and analysis of mechanical properties for deposit body medium

SHI Chong(石崇)^{1, 2}, CHEN Kai-hua(陈凯华)^{1, 2}, XU Wei-ya(徐卫亚)^{1, 2}, ZHANG Hai-long(张海龙)^{1, 2}, WANG Hai-li(王海礼)^{1, 2}, WANG Sheng-nian(王盛年)^{1, 2}

(1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering
(Hohai University), Nanjing 210098, China;
2. Institute of Geotechnical Engineering, Hohai University, Nanjing 210098, China)

Abstract:For deposit body medium, the internal structural properties may be the controlling factors for the strength of the material and the mechanical response. Based on the results of soil-rock meso-statistics using digital imaging, a simulated annealing algorithm is adopted to expand the meso-structural features of deposit bodies in 3D. The construction of the 3D meso-structure of a deposit body is achieved, and then the particle flow analysis program PFC3D is used to simulate the mechanical properties of the deposit body. It is shown that with a combination of the simulated annealing algorithm and the statistical feature functions, the randomness and heterogeneity of the rock distribution in the 3D inner structure of deposit body medium can be realized, and the reconstructed structural features of the deposit medium can match the features of the digital images well. The spatial utilizations and the compacting effects of the body-centered cubic, hexagonal close and face-centered packing models are high, so these structures can be applied in the simulations of the deposit structures. However, the shear features of the deposit medium vary depending on the different model constructive modes. Rocks, which are the backbone of the deposit, are the factors that determine the shear strength and deformation modulus of the deposit body. The modeling method proposed is useful for the construction of 3D meso-scope models from 2D meso-scope statistics and can be used for studying the mechanical properties of mixed media, such as deposit bodies.

Key words:deposit body; mesomechanical mode; model continuation; simulated annealing algorithm; granular flow method