Applied Mechanics and Materials Vols. 99-100

Abstract: Coincidence effect which occurs in a certain frequency range will impairs the sound insulation of walls. For the purpose to predict the phenomenon of coincidence effect that is unlikely predicted theoretically by the mass law, the Statistical Energy Analysis (SEA) theory are adopted in studying coincidence effect of sound insulation of the light weight single-leaf wall. The comparison among predicted by SEA, by mass law and measured was performed. Therefore, the comparison results show that sound insulation prediction by SEA is more precise and agrees with the measured date. Moreover, the coincidence effect and its effect on sound insulation were predicted by SEA. Eventually, it is likely to select appropriate building materials and configuration to achieve a better sound environment theoretically.

Abstract: Abstract: Based on the engineering background of Sichuan Ganhaizi spiral tunnel, this thesis studied the surrounding environment of portal and simulated the whole portal section, and then analyzed the effect of natural light on the portal illumination at different times. With the research on the brightness reduction and human eyes’ adaptation to it, the thesis calculated the discount rate k and obtained the requirements of vehicle speed at Ganhaizi tunnel entrance. Finally, the thesis put forward that some light reduction facilities such as vegetation outside the portal should be used, and on a clear day, from 12:00 to 15:00, the uphill tunnel portal illumination is significantly higher than other sections, thus at this time artificial lighting should be used to modulate entrance lighting.

Abstract: Spatial distribution of slope mechanical parameters on its collapsing and sliding due to seismic load is studied by applying rock dynamic triaxial shear test and finite difference numerical simulation. The results show that a difference in elevation is evident in response of slope initial collapsing and sliding triggered by seismic dynamic influence, i.e., initial fracturing always originates in the place of slope shoulder. Secondly, critical failure strain of slope body unit decreases with its buried depth, and double factors that critical failure strain decreases and peak ground acceleration increases in slope shoulder result in its initial fracturing. Thirdly, dynamic shear strength of slope body unit decreases with its buried depth, and double factors that dynamic shear strength decreases and peak ground acceleration increases in slope shoulder lead to its initial fracturing. The above results contribute to revealing key controlling factors and dynamic process of slope collapsing and sliding triggered by seismic load.

Abstract: During excavating the problem of unloading is a dynamic one essentially. Assuming the unloading ruled by a simple function and based on the Hamilton principal, the distribution of the stress field nearby the tunnel is obtained. The characteristics of the failure nearby the tunnel are analyzed considering the shear failure and tensile failure. The results show that the main mode of the shear failure, intact and tensile failure occurs from the tunnel. The characteristic of the shear failure, intact and tensile failure are one of the likely failure modes.

Abstract: Preparation technology and the performance of aero-concrete using leaching residual slag come from extracting lithium from lepidolite were discussed in this paper. Results show the strength of aero concrete can be slightly improved by using lithium slag instead of fly ash, but the volume density has a major increase, and the gas-forming speed doesn't match the thickening speed. By means of increase in aluminum content and the ratio of water to materials, adding the activating agent, excellent performance products that meet the national standards were synthesized.

Abstract: Acoording to the servic eability limit state, use the numerical analysis the method, using the fiinte element analysis software to the elastoplastic and the big distortion on the power solidifies in the finite element model, by using above coupled non-linear numerical approach, the dynamic response of piles and the earthquake resistance reinforcement. A computation method of raft foundation is brought foward in which many factors are considered. The method corresponds to real foundation working conditions. The results indicated as follows: Under the earthquake load function, the slope and anti-slide piles displacement response was amplified as the seismic motion propagated upwards through the slope. The greater the earthquake acceleration, the larger the deformation of the anti-slide pile. And the displacements of the pile were decreased from top to bottom. The different elevational point of the dynamic moment in the change tendency is the same. the dynamic moment to increase along with the input earthquake wave acceleration increases. There were larger differences occurring in the maximum value of resistances on the partial pile lain in stable rockmass and resistance distribution forms with different accelerations in different times. The calculation indicates that the new method may better reflect the actual locating state and sliding process of debris landslide and anti-slide piles under earthquake.

Abstract: The design and construction of the stiffening steel truss bridges is a complex and large-scale professional program. The abstract of the plans and the weaknesses of the view angles to the design sketch will also become limitations to the owners and the decision makers. Based on the project of River Baling Bridge of large stiffening steel truss girders, this study creates a three-dimensional fine model for it via CAD, pre-assembles each parts of the bridge, and checks sections and dockings one to one correspondingly. Data conversion of this model directly generates virtual visualized model. This visualized fine model of River Baling Bridge provides decision makers with a visual analysis platform, which also offers technical guarantee and support for sensible decision makings.

Abstract: As the main consumption equipment, the air-conditioning system of large-sized public buildings in Xi'an consumes 30%~¬60% of the total energy. Combining with the survey data and related norms, the paper analyses the energy consumption from the following aspects: basic situation of building, index of building energy consumption, ratio of energy consumption of air-conditioning system, load of air-conditioning and indoor environment. Thus, it will give a rational and scientific understanding to energy-efficiency of air-conditioning system of large-scale public buildings in Xi'an for the purpose of providing an efficient assistance to improving the energy consumption of air-conditioning system.

Abstract: With respect to population growth, particularly in developing countries like Iran, this trend has caused people to use personal vehicles more than ever so that application of personal vehicles is more than predicted traffic capacity and potential in towns and megalopolises. This has created several traffic and environmental problems and casualties and financial losses in urban community. For some period of time, the experts and specialists in the field of traffic and urban administration are thinking about some alternative solutions to resolve these problems. One of such alternatives to substitute with using personal vehicle is establishment, development and renovation of public transportation system in all dimensions of megalopolises. At the present essay, it has been tried to explore into public transportation system of Tehran City as one megalopolis and with respect to planning objectives of public transportation in Tehran City, we will deal with the problems and difficulties which this plan is faced by them and eventually by purposing some solutions including optimization of system capacity and accessibility to network, reducing trip time and presentation of some strategies to improve mental imagination of public in using public transportation, we have contributed to create an integrated, efficient and reliable public transportation system.

Abstract: There is potential main landslip and thin-layer siliceous rock undisturbed at the lower part of the left side of Karst slop K133＋180. During the course of excavation, due to the effect of gravity, creep and ulcerate flexion slip surface might occur. From the slope geo-mechanics model perspective, this paper proposes two reinforce schemes on the slope based on the slope reinforce project experiences on the slope of similar condition in the area after taking into account the effect of rainfall conditions. The paper also compares the economic efficiency of the two schemes and considers that, provided that the slope design is stable, scheme 2 shall be more economically efficient. As a conclusion, the left slop K133＋180 was reinforced with scheme 2. So far, the slope keeps stable and firm through times of rainfall. The reinforce experience on the Karst slope K133+180 shall be able to act as a useful reference for similar projects.