Applied Mechanics and Materials Vols. 438-439

Abstract: This paper derives a numerical simulation of direct shearing test and model pile test based on the measured data of bored piles. Characteristics of the interface between bored pile and soil around it are analyzed. Laws of the magnitude and the distribution range of point resistance and frictional resistance of the bored piles in granular and clayey soil are obtained and the mechanism on them is explained.

Abstract: In combination landslide evaluation with three-dimensional visualization of geographic information system and using virtual reality technology to build a 3D visualization platform for landslide assessment, as a whole, it is more vivid and intuitive synthesis of landslide visualization research. Based on the design principle of the analysis on system separately from the data acquisition and processing for construction of three-dimensional model, the landslide process rehearsal, stages of disaster evaluation and other aspects of the system are analyzed and studied, which provides a powerful tool for the study and prevention of geological disaster. Moreover, it can bring significant benefits to society, economic and ecological system.

Abstract: In this paper, large-scale finite element structure analysis software ANSYS is used for calculation and analysis of spillway prestressed pier, the rationality of shape design of the spillway side pier structure is demonstrated, the layout scheme and persistent tonnage of the prestressed anchor cable is optimized. The results can provide reference for design of similar structures.

Abstract: With the growth of population, shortage of water resources, natural disasters, climate change, serious shortage of land resources and the development of urbanization and industrialization and impacts of other unfavorable factors, China's grain security issue has become a focus of public concern. Through the Chinese population quantity analysis and forecast of 2020 and 2030 the total demand of grain, comparison between total demand and current level of food production, China's grain problem is facing tremendous pressure. Water conservancy is the lifeline of agriculture and irrigation has great potential for grain production guarantee. Results for food safety in China made the following responses: First, the rational use of water resources, improve the efficiency of irrigation and grain yield per unit area. Second, multiple sectors such as agriculture, meteorology, soil, make a good combination of multiple disciplines for food security. Third, increase the peasants' production enthusiasm. Last, scientific and technological progress is the guarantee of grain production. In General, the issue of food security is national security, social stability, a top priority. The combination of our country's water resources crisis, limited rational development of agricultural water resources, improve the efficiency of irrigation, which will provide a guarantee for China agricultural water crisis, alleviating the shortage of water resources and increasing food safety assurance.

Abstract: Controlled alternate furrow irrigation is one of the new irrigation methods. In order to research the adaptation of soybean, soil water movement and water utilization efficiency under controlled alternate furrow irrigation in the north China, the experiment was done with Lysimeter in Kaifeng. The results show that compared with conventional furrow irrigation (CFI), the controlled alternate furrow irrigation has suitable irrigation quantity that is not only helpful for enhancing water use efficiency, increasing yield, but also helpful for reducing deep percolation. Therefore, the controlled alternate irrigation is a feasible irrigation method in Kaifeng. However, the quantity of controlled alternate furrow irrigation can be too low to enhance the yield of soybean and economic benefit.

Abstract: We proposed a new type of aggressive concrete structure in this paper. The proposed structure consists of concrete columns reinforced by ultra-high strength rebar with spiral groove on its surface. Four circular concrete columns were fabricated and tested under cyclic reversed lateral force and constant compression to investigate the seismic behavior of the proposed columns. Test results have shown that the concrete column had high resilience, and use of the ultra-high strength rebar with spiral groove on its surface could significantly mitigate damage degree and reduce residual deformation of concrete column. Based on the experimental results, we developed a model to simulate the hysteresis loop of the proposed resilient column and an equation to assess the equivalent viscous damping ratio, which was indispensable to performance-based design of the resilient column. Very good agreement was observed between the measured results and the theoretical predictions.

Abstract: In building structure, staircase is more complex and relatively weak. As an important emergency routes when earthquakes and other emergencies (such as fire, explosion, etc.) take place, stairs subject highly evacuation live or seismic load, destruction of the stair caused delay of evacuation and affected the commencement of rescue work, and produced serious injury or death. Investigation of Wenchuan earthquake damage also finds that many stairs broken before the main structure. In the current code for seismic designof building, seismic design advice of stairs was only given instructionally, and specific calculation methods and construction requirements were lacked. Based on the analysis of earthquake destroy of stairs in frame structure, this paper proposes some design requirements of stair.

Abstract: The main purpose of this paper is to study the seismic performance of prestressed reinforced concrete pile (PRC pile) reinforced with nonprestressed reinforcements. Two prestressed high strength concrete piles (PHC piles) and two PRC piles were tested. The variables studied in this research are the prestressed reinforcements ratio and nonprestressed reinforcements ratio. The piles subjected to low-cycle loading were presented in this paper, including the hysteretic performance, stiffness degradation curves, coefficient of equivalent viscous damping and skeleton-frame curves. It is shown that the failure modes of all specimens are bending damage from the test and PRC piles have good energy-absorbing hysteretic behavior.

Abstract: In order to study the far-field ground motion characteristics and the attenuation of seismic waves, the peak ground acceleration (velocity, displacement), time of duration and response spectrum of the seismic waves were analyzed in this paper. Through the investigation of earthquake wave propagation process, the seismic attenuation low was analyzed. This study can provide technical support for the seismic design of long period structures and related engineering application.

Abstract: The key to near-field strong ground motion simulation based on stochastic finite fault method is to determine the spectrum of ground motion. We present an improved source spectrum model for simulation near-field strong ground motion acceleration time history. We combine Masudas source spectrum model with scaling factor H_ij to keep radiation energy conservation and reflect the energy decrease with frequency at low to mid frequencies. We calculate the Fourier amplitude spectrum F_a, accelerate response spectrum S_a, velocity response spectrum S_v and displacement response spectrum S_d of simulation time histories. By comparative analysis of the laws of spectrum values (F_a, S_a, S_v, S_d) with the variation of frequency or period, we discusses the effects of sub-fault dividing scheme, the method of determining scale factor and source spectrum model on spectrum values (F_a, S_a, S_v, S_d). The results show that sub-fault dividing scheme has slightly effect on the model presented in this paper, and the model enable to reflect the sink laws of source spectrum value in mid-to-low frequencies well. We demonstrate that the improved model is superior to other commonly used models.