Applied Mechanics and Materials Vols. 488-489

Abstract: Based on finite element analysis o f concrete filled steel tube beam-column joints under the single axial compression ratio and concrete strength, further research was done to analyze the seismic performance of concrete filled steel tube beam-column joints under different axial compression ratio and concrete strength. Beam-column joint which is connected by bolts with welding extended steel sheets at the beam root was analyzed. The results show that with the increase of axial compression ratio, strength and stiffness degradation of the joint accelerated gradually. Axial compression ratio at 0.3, 0.4 are appropriate values for joints specimen, load-displacement hysteresis curve of joint specimens is relatively plump and shows good seismic performance. Chance of concrete strength also had effect on seismic performance of joint specimen, but in contrast it is not so obviously.

Abstract: The microstructure evolution and hardness change were studied for a vanadium-containing steel rebar at different cooling rates. The experimental results show that bainite and martensite gradual emerged with the increasing cooling rate and resulted in an increasing micro-hardness. Bainite or ferrite and peartite should gradually disappear when the cooling rate increased to a certain value. The cooling rate should be controlled below 10°C/s to ensure good performances. The CCT curve of HRB400E measured with the inflation method and metallographic-Hardness method could provide the theoretical basis for controlled cooling process.

Abstract: In this paper, adhering to the "safety first, prevention first" concept, analyze the reason for the accident risk may occur during welding operations, and puts forward the safety prevention measures. To ensure the welding process of construction personnel and property safety.

Abstract: As the renewable energies become more and more popular due to the conflicts between economic development and environment, not only the utilities but also the residential consumers start to think about installing alternate and renewable generations. For residential use, the renewable energy sources can provide alternate energy resource in case of outages as well as save the utility bills. This paper is to provide suggestions for residential installation of renewable and alternate energy based on technical and commercial feasibility analysis and give the recommendations on installing wind energy, PV system and energy saving tips.

Abstract: A study has been carried out to investigate and analyze the structure of the ecological green space in Urumqi with techniques of Remote Sensing (RS) and Geography Information System (GIS). Combination of multi-band of TM image has tried in the study to interpreter the green space in Urumqi, which could draw the information on urban ecological green space accurately. On the basis of the results of rational classification, the structural characteristics of ecological green space in Urumqi have been analyzed and the existing problems have been discussed, finally the strategies and measures that should be taken in future have been put forward for building better ecological green space in Urumqi.

Abstract: As traditional measurement while drilling (MWD) method cannot meet the high reliability, high precision requirements for drilling complex structure wells. A guided-orientation method based on rotating magnetic field has prominent advantages on the twin parallel horizontal wells and can apply in twin parallel horizontal wells. In this paper, RMRS, namely Rotating Magnet Ranging system, its operating principle was gave firstly while applied for drilling twin parallel horizontal wells. The rotating magnetic sub was characterized by a pair of orthogonal magnetic dipoles, and then build the model for positioning the twin parallel horizontal wells Finally, the authors used the Maxwell software to simulate the algorithm based on the scene environment, and then proves that algorithm is correct and useful for guiding the well to drill and keeping the twin wells parallel.

Abstract: Along with the fast development of transportation infrastructure construction in our country, the highway tunnel construction is increasing and tunnel construction has become an important part of the current construction. Because the tunnel has a wide span and the construction procedures are tedious, the changes of the stress of surrounding rock and supporting relationship are complex, problems easily tend to occur. With the Great Wall Mountain Tunnel as the engineering background, this artical carries out the research on characteristics of deformation and fracture of the overlying rock on the tunnel and the geomechnical model test of testing technology of the fault fracture of surrounding rock. Through comparative tests, the graphite type wire is finally chosen. This material can basically synchronize with the fault fissure of model medium, meet the test requirements and have great significance in engineering application.

Abstract: In our country, the progress lag even casualties caused by landslide or collapse of tunnel portal occurs from time to time, so how to make scientific analysis on the stability of side slope of the tunnel entrance and put forward effective control technology are important problems urgent to solve in tunnel engineering. This paper mainly analyzes the influencing factors of stability of side slope of the tunnel entrance and failure mode of side slope and puts forward the corresponding control measures to ensure the safety of the tunnel construction.

Abstract: In typical Karst mountain area, the complex and broken ground surface leads to serious mixed pixel phenomenon. In this paper, with Tuchang Town as the research area, we utilized linear spectral mixture analysis to estimate biomass of grassland from Landsat ETM+ image. The analysis indicated that the grassland component which extracted based on the linear mixed model has obvious lineal correlation with the field measured data. The grassland aboveground biomass estimation model can be expressed by the equation: Y=2451.158X-280.461, (R²=0.8012). The result of precision validation shows that the overall accuracy is above 85%. The grassland aboveground biomass estimation model which based on linear spectral mixture analysis is feasible.

Abstract: Nearly 20 years, rare earthquake appeared frequently.The data shows that the world has entered a more active seismic activity period.The impact of earthquake damage to human life and property safety intensified, China is facing the same or even more pressing issue.Therefore, improving the seismic performance on active service structure reinforcement and reconstruction, to reduce earthquake damage, protect people's property security, to reduce the social and economic loss is of great significance. Performance-based seismic design theory, is a multi-index, multi-level seismic fortification system, it is reasonable, flexible development of seismic fortification goals.If apply this thought to structure of the seismic strengthening, forward-looking and innovative, has enormous social and economic benefits as well as the wide research prospects.