Applied Mechanics and Materials Vols. 295-298

Abstract: Taking a typical continuous girder bridge for example, the text builds spatial beam finite element model. By nonlinear time history analysis method, it analyzes bridge transverse pounding and the retainer strength in different strength levers earthquake. According to bridge pier failure and fragility theory and retainer section moment-curvature analysis, it puts forward retainer failure types in different strength levers earthquake. The calculation results show that it is irrational to design retainer section and reinforcement based on structure requirement. The structural retainer failure types have uncertainty without considering bridge seismic fortification goal. Though it appears on ductility failure, the damage state is very serious.

Abstract: In the oil field development and production, fluid flow is an extremely important parameter which determines the transmission characteristics of the oil production, real-time monitoring of fluid flow parameter provides a scientific basis for oil and gas optimization exploration and increase of reservoir recovery. A method for interrogating fiber optic sensors using flow-induced pipe vibration is proposed, then the fixed relationship between standard deviation of pipe wall’s vibration induced by fully developed turbulence and mean flow rate is determined, by the abundant experimental data analysis,The vibration frequency characteristic of the pipe’s vibration signals is found in the experimental system.and fluid flow is measured non-intrusively, the study is conducted on vibration induced by turbulent flow when fluid flow through pipe.

Abstract: In order to meet the requirement to quickly solve the water quality equation for an unexpected water pollution incident, this dissertation, based on the paralleled algorithm under Java Parallel Processing Framework (JPPF), does research about the process to dynamically decomposes the iterative process into calculation tasks and distribute the tasks by the API of JPPF to the paralleled nodes for calculation. And the simulation result of one-dimension water quality equation shows that parallel computing method could reduce the time complexity from to , not only resulting in a significant improvement in calculation speed, but in a higher reliability and stability.

Abstract: A simplification model of infiltration in clay soil was developed. The model consisted of two flow domains: soil matrix and macrospores. The model was tested against the results of infiltration transients through a large clay soil column. In order to quantify model parameters, characterization of soil matrix was carried out, providing hydraulic conductivity curve. All of the other model parameters were obtained by calibration due to lack of relevant experimental data. The proposed model proved to be able to adequately simulate measured breakthrough curves as well as temporal evolution of water content profiles along the sample.

Abstract: Soil moisture is one of the most important land environmental variables, relative to land surface climatology, hydrology, and ecology. A method to estimate soil moisture content from optical and thermal spectral in-formation of ASTER imagery based on thermal inertia is presented in this paper. Compared to models published previously, four improvements have been made: (1) as a key component of soil surface energy balance, the series two-layer is applied to solving soil latent and sensible heat flux in the better-covered vegetation area. And the Shuttleworth and Wallace (S-W) ET model is used to simulate soil latent flux; (2) because component temperature inversion is still an ill-posed problem, genetic inverse algorithm (GIA) is used to realize retrieval of component temperature; (3) in order to extend the scope of the thermal inertia model, B in the equation is derived from mechanism; (4) to eliminate partly atmospheric and the surface structure influence, the improved thermal inertia was normalized to fulfill the inversion of soil moisture. Taking YingKe green land in china for example, field experiment were carried out to validate the developed model. The method successfully estimated better-covered vegetation region surface soil moisture with an average error of 0.067. This model provides a new way of thinking about remote sensing thermal inertia methods to acquire regional-scale soil moisture.

Abstract: The daily precipitation of nine rainfall stations in recent ten years were taken as the analysis data. Combining the statistical method with GIS, the rainfall erosivity of nine rainfall stations was discretized spatially. And its temporal characteristics were analyzed by the statistical method of Mann-Kendal. The results showed that in the past ten years, the inter-annual rainfall erosivity distribution was uniform and its distribution in spatial was even. But in one year, the monthly rainfall erosivity exhibited strong variability and showed a bimodal distribution. And the two peak value occurred in July and August respectively. These results were useful to estimate the soil erosion and to divide the soil and water conservation zone in Shanghai.

Abstract: Grassland is an important ecosystem in land surface. Soil is the basis of grassland ecosystem, and the changes of its properties directly affect grassland ecosystem. The study region is located in Xilamuren grassland using the methods of field sampling and experimental analysis. It was divided into four test areas according to grazing intensity. Soil physical and chemical properties were analyzed in each test area. The results showed that: the trend of soil water content decreased and then increased with increasing grazing intensity, soil water content in repaired grassland was the lowest. For the soil mechanical composition, particle size content increased first and then decreased with increasing grazing intensity when the particle size was 1-0.05mm. The difference between the highest and lowest values was obvious. When the particle size was 0.05-0.002mm, the trend of particle size fluctuated, first decreased and then increased, finally reduce again and the difference between the highest and lowest values was obvious. When the particle size was less than 0.002mm, the trend of particle size content increased with increasing grazing intensity. In soil chemical properties, soil organic matter appears downward trend overall as grazing intensity increase. Soil organic matter content was the lowest in repaired grass. Available N and P first decreased and then increased with increasing grazing intensity, the minimum values appeared in the repaired grassland and degraded grassland respectively. Available K content increased with increasing grazing intensity.

Abstract: Jiangjiagou valley is an area with most developed debris flow valleys in China. Based on Jiangjiagou valley, according to the difference of magnetic characteristics in sediment and soil, this paper studied quantitatively the sediment sources. The results showed that sediments mainly came from landslide debris, accounting for 97.56%; the contributive ratio of grassland and sloped farmland for main channel sediments was very low. It was accordance with using 137Cs tracer technique. But there are still some limitations, and further strengthen research and discussion with combination of 137Cs isotope tracing.

Abstract: Nowadays, desertification is a common major environmental problem confronted by human society. Analysis in dynamic change of desertification is one of the tasks to control it, and the interpretation of desertification data is the base to analyze the dynamic change. Based on the analysis of collected data of geology, geomorphology, soil, climate, hydrology, and vegetation, the author indicates that different periods of desertification degree distribution maps can be obtained by selecting multi temporal TM images of the study area in recent years, which are interpreted by the tool of RS & GIS. Then, Kubuqi desert is researched as a sample and desertification dynamic change is discussed in terms of desertification area changes, spatial changes of desertification levels. The main ideas can be deduced as follows: 1. The results indicate that frequent human activities will speed up the degradation and deterioration of ecosystem in Kubuqi desert where environmental capacity is small. 2. In addition to general engineering and biological measures, tourism development should be taken into consideration to eliminate the root causes of irrational human activities and keep dynamic balance of ecological systems and human environment.

Abstract: Qilinsi hydro-electric power station is constructed for power generation. This paper analyses the influences of seven aspects to water and soil erosion in project constructing, such as construction occupation land, dig and backfill of main body, project discard- dregs, materials field exploitation, construction traffic roads, immigrants installing and geologic disaster. The water and soil erosion quantity was predicted. Prevention measures for water and soil erosion were presented correspondingly and it has important significance for constructing the project successfully and improving circumjacent environment.