Papers by Author: Pei Feng Sun

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Authors: Ryong Hyon Hwang, Tian Hong Yang, Pei Feng Sun
Abstract: In general, rock mass is anisotropic because of presence of stratification, foliation or joints in it. In this paper we considered how the angle of anisotropy influences the stability of tunnel. By using COMSOL Multiphysics, fluid and 2D plane models are coupled to analyze stress-strain state, failure shape and water flow characteristic around tunnel for angle range from 0° to 90° with a interval of 15°. Results show that in condition of vertical force of initial stress field larger than horizontal one, failure district is maximum for θ=40° and minimum for θ=90° where the strength of horizontal direction in anisotropic rock is smaller than the vertical one. In this case failure is mainly developed in roof and bottom. When the horizontal strength of anisotropic rock is larger than the vertical, results reverse. In anisotropic rock, the more the direction of larger permeability is coincident with one of source underground water acted, the more water flows into tunnel.
Authors: Pei Feng Sun, Tian Hong Yang, Qing Lei Yu, Wei Shen
Abstract: With ShapeMetriX3D rock non-contact measuring technology, structural planes’ distribution of MiaoGou iron mine slope is got. Then, the Mont-Carlo method is used to create equivalent fracture network, with that scale effects and anisotropic properties of rock mass are studied by RFPA2D, considering different scales and directions in statistical window. The results show that both deformation modulus and the strength of the rock mass’s REV are 2.5 m. Furthermore, the strength ratio of filler to rock (K) and the strength of the rock mass fit the logarithmic relationship in rough, while the elastic modulus ratio of filler to rock (M) and the strength of the rock mass fit the linear relationship in rough. The strength of no joints rock mass is much stronger than three times of the strength of jointed rock mass, but the rock mass elastic modulus of no joints is less than 1.6 times of the elastic modulus of jointed rock mass. The research results are directive and have reference value for the study of anisotropy mechanical parameters of rock mass engineering.
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