Applied Mechanics and Materials Vols. 353-356

Abstract: Advanced small pipe support is one of the advanced support patterns in tunnel engineering construction for weak and fractured surrounding rock. The support effect cannot be predicted because of depending on engineering experiences. Efforts are made to study and analyze the support mechanism of advanced small pipe in the excavation of soft - fracture wall rock. By the numerical simulation of FLAC^3D of Dawangou tunnel based on rock mass deterioration model (RDM), the plastic zone, displacement and stress filed of the surrounding rock are simulated with and without the advanced small pipe support. The support effect of advanced small ducts in tunnels during excavation by steps is presented.

Abstract: In response to the limitation of conventional index for stability and optimal design of underground rock mass engineering. The new evaluating indicator, local energy release rate, which can analysis the energy release intensity in the process of the brittle failure of hard rock is used in numerical analysis. Numerical simulation of construction sequence was studied for Dawangou tunnel using energy release rate index and a new constitutive model reflecting the brittle failure of hard rock. Based on the change trend of energy release rate, rock displacement and plastic zone, an optimization excavation is suggested. The optimal excavating sequence could serve as reference in the design and construction.

Abstract: For analyzing and evaluating the deformation features of channel goaf foundation and its effect on superstructure, according to the foundation reinforcement engineering of Ji-Liang Channel Check Gate, the comparative analysis on the differential settlement between the unfavorable foundation and natural foundation was performed by numerical simulation with FLAC^3D. The computer results showed that the present foundation had obvious effect on the stability and security of the superstructure, so the engineering treatment are needed. Based on technical-economic comprehensive analysis among three treatment methods for strengthening the channel golf foundation with different kinds of filling, the reasonable method is put forward in this paper. By comparing mechanical characteristic of flashboard in channel goaf before and after strengthening, we confirmed the foundation stability of channel goaf and the security of the ground building which can satisfy the long term usage requirements.

Abstract: This paper aims to study the impact of resonance on floating body motion. According to Archimedes law, Newton's second law of motion and general form of simple harmonic oscillations, nature frequency is gotten in the numerical calculation. Then, the result is validated using four bodies with different weights in numerical calculation and finite element simulation.

Abstract: The pedestrian safety and comfort is closely related to the wind environment around the commercial complex building. In this paper, we simulate the steady-state three-dimensional flow field around a commercial complex building which is still under construction in Shenyang city by using CFD (Computational Fluid Dynamics) software. The distribution of wind speed and pressure around the commercial complex are obtained. In summer wind speed around complex is 0.5-3.6 m/s and the differential pressure greater than 1.5 Pa under the dominant wind. In winter wind speed is 0.5-4 m/s and the differential pressure less than 5 Pa except windward under the dominant wind. Local vortex appeared in both summer and winter due to the shape of complex building. The commercial complex building also had an impact on the wind environment of the surrounding buildings, larger the building, greater the impact.