Applied Mechanics and Materials Vols. 94-96

Abstract: Wenchuan earthquak induced a large number of mountain hazards. Through the survey found that manual excavation slopes tend to become concentrated area of mountain disaster, it’s indicate that the effect of excavation damage on the slope deformation and failure under seismic load is very obvious. Anti-dumping slope deformation as one types of mountain hazards induced by Wenchuan earthquake, and it’s also seriously affected by excavation damage. In this paper, as Wang Jiaping landslide for example, using the finite element method to simulate the landslide and analysis the deformation and failure of slope affected by the excavation damage. Analysis shows that deformation and failure of slope is significantly induced by excavation, and resulting in displacement, stress and the between layer sliding distance increased，the between layer friction stress reduced. The results agreement with the characteristics of the anti-dumping slope deformation and failure induced by Wenchuan earthquake mainly concentrated in excavation slopes.

Abstract: Speaking of the existence ground fracture disaster's city, have to ensure the safety of various types of civil engineering structures, and also be effective to use city land, this is the problem which need civil engineers to research and solves. With Xi'an ground fracture sites as the background to discuss this issue, from the vulnerability classification of urban land, the building importance rating, structural safety performance research so on, propose several methods of the ground fracture field can be effectively to use, final several good cases are given through the investigation and analysis. These methods are: In the ground cracking or possible cracking sites, with urban and community plan, can consider the layout of a city square and green space; unimportant temporary buildings can be built in the main deformation zone of the ground fractures; For the ground fracture activity tends to be stable, or to be in the sleep, the safety of multistoried buildings crossing fractures can be met; Determining the important building's minimum required secure distance, needs through the structure safety performance analysis and the research.

Abstract: Tunnels of new across the old one with short distance is the emphasis and difficulty in metro engineering development, which has great research values. According to the characteristic of deformation on overlap tunnels with short distance, we put forward the calculating model of lining deformation and internal force analysis. And deduced the formula of calculation on the new tunnel's construction to adjacent ones, then discussed and analyzed the settlement of the point of inflection on soffit lining and the greatest subsidence angle. We verify the theoretical formula about the reliability of the computation and rationality through a series of numerical simulation test against the background of Qingdao overlap tunnels.

Abstract: Abstract: Xigeda stratum is a kind of extremely soft rock with bad engineering property and its rock easily gets soft when wet which gives rise to geologic hazard, thus side and heading slope excavation at tunnel opening often causes collapses. Based on the construction technology of Gan Haizi tunnel in Yaxi express way, this thesis will first analyze its strata characteristics, and then focus on the methods of stabilizing side and heading slope, as well as the effective means to avoid opening deformation, so that the construction and operation can be carried out safely.

Abstract: In order to obtain the internal frost heaving force development characteristics and change rule of frozen wall in the process of the formation and melting in cretaceous stratum, and then take analysis of mechanics features and safety evaluation of frozen wall, in a mine of Inner Mongolia, the field measurement research of internal and external frost heaving force and pore water pressure in the freeze-thaw process of frozen wall has been carried out. The measured results show that it formed uneven frost heaving stress in internal and external of frozen wall in freeze-thaw process, in the test the maximum of freezing pressure reach to 6.0MPa, it is 2.4 times of initial pressure in the layer; When the shaft excavated to test layer the freezing pressure reduced linearly, then the freezing pressure rebounded slightly when the wall was pouring, and finally the frost heaving force reduced to 0 when frozen wall melt, back to the pressure effected by soil and water.

Abstract: The seismic responses of solid pile and hollow pile were analyzed and compared in this paper. According to the deflection equation of pile during earthquake, rotation, bending moment, shear force and soil resistance of pile were obtained. The differences of deflection, rotation, bending moment, shear force and soil resistance between hollow pile and solid pile, whose effective areas of cross-sections were same, were found. From calculation results, hollow pile had certain advantages in seismic performance. This study provided a theoretical basis for the applications of hollow piles in practical engineering.

Abstract: In order to prevent the hazards of rock burst and the spontaneous fire in deep-level mine and ensure that the ventilation run safely and reliably, the variation trends and the distribution rules of the air flow in deep-level mine are analyzed. Based on the network flow theory and statistics principle, the density equations of the air quantities in the airways are established. With the maximum likelihood estimation (MLE), the rationality of the parameters in the air quantities distribution equations is verified. By means of the disjoint minimal path set algorithm, the reliability assessment models of mine ventilation network are founded. All the calculation processes are realized in the environment of MATLAB. The results indicate that the indexes of the quantitative analysis reflect the practical situation of the ventilation network in Daliuta coal mine.

Abstract: Aiming at the collision phenomenon of the curved continuous girder bridge under the earthquake, the three-dimensional finite element model is established considering the collision element between the abutment and the end beam. Using the nonlinear time-integration method, the simulation analysis on the collision with implicit contact algorithm is used, and the collision law at expansion joints of curved gride bridge is studied. The results indicate that the shear forces and bending moments of piers with different heights are different. The collision force at the central part of the cross-section is small, and it gradually increases toward both sides of the cross-section with parabola. The outer collision force is bigger than the inner collision force, and the response of Elcentro ground motion is more obvious than that of Tianjin. The results may serve as a reference for seismic design of curved continuous bridges.

Abstract: The open trench D ramp of Yingpanlu Xiangjiang tunnel in Changsha and the adjacent building foundation pit construction were excavated almost at the same time. The minimum distance between the two pits was only 8 meters, and keeping both projects safe working became difficult in engineering. Therefore a special project example of numerical analysis model was established, which can simulate the whole construction course. The construction stress was analyze by combining with the soil and retaining structures displacement, and the results were compared with the actual measured data to provide a reference to the design and construction optimization.

Abstract: To meet emergency logistics need pre- or post-disaster, a topology network-based approach is introduced to solve the complexity of highway transportation system. It classifies the transportation system into sub- networks and central networks where a virtual local area network is designed in order to fulfill function of information exchange and road condition renewal between different forwarding stations. To renew real-time road conditions and data in terms of business or operation for each node, a virtual transportation network is designed based on foundation of central networks, which consequently reduces algorithm measure and also speeds up path-selection procedure.