Abstract:This paper adopts Hilbert-Huang Transform and Random Decrement Technique to evaluate amplitude-dependent damping of a steel building from strong motion records. The results demonstrate that amplitude-dependent damping is an inherent nature of steel buildings. Damping first increases with amplitude at the initial stage, then starts decreasing with amplitude after reaching a "critical amplitude". Based on Hilbert-Huang Transform and Random Decrement Technique, it is feasible to identify nonlinear damping ratios with respect to amplitude from strong motion records.

Abstract:An increasing attention has been directed to applying the artificial neural network (ANN) method in civil engineering. This paper examines the possibility of artificial neural network (ANN) to predict the chloride diffusion coefficient of concrete. A total 653 available sets of data from 13 literatures was used for establishing the network model. The developed ANN model used as many as 13 input variables, including water/cement ratio; the dosage of cement, superplasticizer, fly ash, granulated blast furnace, silica fume, aggregate; compressive strength; curing mechanism; testing method; testing time and environment to achieve one output parameter, referred to as chloride diffusion coefficient. The research results show that ANN is feasible in predicting the chloride diffusion coefficient in offshore concrete structures and the selected input variables are all correlated parameters.

Abstract:In order to study the influence of the temperature change on load characteristics of pile foundation in permafrost region, this paper analyze the effects of different temperatures on the mechanical behavior of pile foundation under earthquake by using MIDAS/GTS finite element analysis software. The characteristic values, the relative displacement and bending moment curve under the condition of different models were obtained through numerical calculations. Combining with the actual value of comparative analysis, the results showed that increase of temperature has great effect on pile foundation during earthquake, pile foundation is easy to be broken.

Abstract:The compacted clay liner used in the landfill site will produce cracks due to the natural wet-dry cycling, which will affect the permeability of the soil. This paper selected a kind of kaolin with a diameter of 6.18cm and height of 4cm small ring knife to make sample, which was used to study the effect of the whole shrinkage of small size specimen on the development of surface cracks in different temperature and wet-dry cycles. The results shows that the small size of the sample is extremely easy to produce the whole shrinkage with the increase of the dehydration time, which restrains the generation of surface cracks and eventually leads to the destruction along the side surface. Under the condition of high temperature dehydration, proper wet-dry cycling times can reduce the effect of the whole shrinkage on the cracking.

Abstract:In order to study different powder/asphalt ratios effect on high temperature performances of mortar, this paper chooses limestone as the filler, and powder/asphalt ratio is 0.2, 0.4 ,0.6, 0.8. Mortar high temperature performance evaluation index selects Fail temperature and ZSV through DSR test. The test results show that with the increase of powder/asphalt ratio, Fail temperature and ZSV value of the mortar increase gradually, and the amplitude is larger. High temperature performance of the mortars improves obviously. By using environmental scanning electron microscopy search for those mortars, the results show that crumb rubber modified asphalt mortar of powder is smooth and delicate, the powder is covered uniformity by crumb rubber.

Abstract:Conclusions of researches on the relationship between concrete splitting tensile strength and axial tensile strength are inconsistent. To study the relationship, splitting tensile test with loading strip width ranging from 5mm-20mm and axial tensile test were conducted. The size of splitting tensile test cylindrical specimens is 150mm×300mm and size of the axial tensile test specimens is 100mm×100mm×550mm. Based on cohesive crack model of fracture mechanics theory, this paper builds a regression equation between fts/ft and D/L_ch. The parameter's values of the formula are also given. It can be proved that the formula is acceptable and can be applied in design and detection of massive concrete structures.

Abstract:In practical engineering, slurry ratio are usually confirmed by experience, which causes slurry properties and formation mismatching, and cannot get ideal grouting effects. In this paper, we will start with the slurry ratio, using single factor analysis to measure permeability coefficient by doing variable head test. On the basis of experiment, we can discuss the change law of slurry permeability in different slurry ratio, and make a further analysis of the matching relationship between slurry and formation. The results showed that: when other components of slurry remain unchanged, slurry permeability decreased along with the cement, fly ash, bentonite growth, and increased along with sand, water reducing agent growth, which could provide an reference for selection of slurry in future engineering.

Abstract:In order to understand fully the failure mode of steel-recycled concrete beam, four steel-recycled concrete beams were tested on their bending performance. Through the test, the mechanical characteristics and deformation mode of steel-recycled concrete beams from the starting loading until to damage were completely recognized. The effect of different coarse aggregate substitution rate and reinforced stirrup on its mechanical features were also analyzed. The results show that different coarse aggregate substitution rate have little effect on the ultimate strength of steel-recycled concrete beam. The stirrup ratio have certain influence on the crack distance and development of beam. The?horizontal?section?assumption is feasible to the Steel-recycled concrete beam. The research conclusions can be a help to relevant study and engineering application.

Abstract:The performance of distortional-local interactive buckling on stiffening lipped angle steel members under axial compression is studied in the thesis by using ANSYS finite element software. The effect of different edge width on buckling mode and critical load and the effect of different panel thickness on distortional-local interactive buckling critical load are studied. The results indicate that: Edge width has great effects on distortional-local interactive buckling mode and critical load of the component. The critical load value under different edge width is contrasted to get a reasonable edge width and limb length ratio range; the panel thickness has great effects on the critical load of distortional-local interactive buckling. The change of economic coefficient under different panel thickness is contrasted to get a reasonable panel thickness and limb length ratio range.

Abstract:To obtain the extremely low-cycle crack initiation life of thick-walled steel bridge piers, numerical analysis of the thick-walled steel bridge piers is carried out. The hysteretic behaviors of thick-walled steel bridge piers under three different kinds of cyclic loading patterns are predicted by using combined hardening model as constitutive law of steel. Crack initiation life of steel bridge piers corresponding to different mesh sizes is determined by using both local and non-local damage methods in Ge model. Then, some parametric studies are carried out to investigate the effect of radius-thickness ratio and slenderness ratio of the piers on crack initiation life by employing Ge model. The analytical results show that the combined hardening model of steel can accurately predict the hysteretic behavior of thick-walled steel bridge piers, and non-local damage method can be employed to accurately predict the crack initiation life of steel bridge piers. On the basis of parametric analytical results, empirical formulas for predicting the crack initiation life of steel bridge piers are proposed.

Abstract:In order to study the piled wharf in the influence of earthquake disasters in use process, combination with the engineering practice, based on the numerical simulation analysis technology, the transient dynamic analysis of earthquake under the course calendar piled wharf upper structure crack propagation conditions is analyzed. Based on crack propagation depth and the distribution of crack two indicators of piled wharf upper structure under seismic disasters 4 level security evaluation method, and validated by the crack propagation analysis under different earthquake magnitude. Results show that under different earthquake magnitude 4 safety assessment methods for safety assessment of piled wharf is feasible. To assess the damage to the wharf under different earthquake magnitude, to predict earthquake disasters in advance to the damage degree of wharf, provide a scientific basis for improving design.

Abstract:In order to have a more objective position on the world level of the standard value of vehicle load in China and make a foundation for the revision of the resent standard of Highway Bridge. This paper has explained the China's new and old code and the United States HL-93 specification for the design of vehicle loads, then take 6, 8, 10, 13,16, 20,30 meters long span bridge with T shaped beam for example, to make a systematic calculates of mid-span moment and shear force at supporting point of T-shaped beam, which is under the action of vehicle load in the Chinese and American Codes. In the end, the absolute value and the relative value of the load effect are analyzed systematically. The results show that: compared with the United States, the Chinese standard is relatively conservative and not intuitive, China's current vehicle load standard specification in the international is roughly in the middle position, considering the contact with the original specification, the appropriate reference to the United States.

Abstract:Based on a pre-stressed concrete hollow slab bridge which located in Shandong province, the engineering security of truck weight limits model on highway bridges was verified systematically. Firstly, the bridge of carrying capacity is checked to verify the bridge weather meet the design requirements by according to the bridge design data and the design of truck weight of 2004 code .Then, the load effect and the deflection of mid-span of bridge in different typical truck of weight limits were calculated by according to the design of the truck lateral load patterns aiming at different safety classes ,respectively. And the data were compared with the design of truck weight to verify the engineering security of truck weight limits on highway bridges. The results indicate that, when the safety class of bridge truck weight limit were class one and class two, the corresponding typical truck of weight limits can satisfy the carrying capacity requirements of class one, class two and class three. when the safety class of bridge truck weight limit were class three, the corresponding typical truck of weight limits can satisfy the carrying capacity of normal section requirements of class one, class two and class three, but hardly satisfy the carrying capacity of cross section requirements of class one.

Abstract:Defining the central city of Nanyang central city as the subject and basing on the space syntax theory and methods of spatial analysis to establish a scientific model of analysis and comparison of visual images and spatial form variable values, this paper summed up some characteristics and rules of the spatial evolution of Nanyang from 1955 to 2015. The results show that the urban space change from single center to multi center urban development patterns of progressive and the White River plays an important role in urban spatial structure evolution; urban main axis of the first in the history of the city is Xinhua Road, then gradually transit to the north and South Dushan Avenue and the urban space structure become the "liberal hub" type space structure controlled by multi axis.

Abstract:Fengfeng Mining Area in Handan is a national famous century-old mine,of which the Second Mine is one of the main coal mine which has been abandoned for years due to resource depletion. The thesis will take the small coal mines-the second mine in Fengfeng Mining Area as the research object and combine with spot investigation and present situation analysis to do a deepen research on the landscape planning in small coal mine industrial wasteland, which wish to provide reference for landscape reconstruction in other small coal mine industrial waste land.

Abstract:To reduce the losses caused by fire disaster of underground commercial street, Using Interval Analytic Hierarchy Process (IAHP) to assess the risk of underground commercial street fire disaster. Applying modified Delphi method from 4 aspects such as :fire resistance property, fire-fighting capability, fire management and evacuation capability to build third-level safety evaluation index system of underground mall fire disaster. Adopting IEM to calculate the weight value of each index, and conduct the rank of weight value under the overall objective. To confirm the reliability of evaluation model, Took west Xiangtan underground commercial street fire disaster system as an example for calculation, the result of evaluation showed that the main risk factors of the underground commercial street of west Xiangtan fire disaster are divided into three aspects: ability of escaping, fire fighting propaganda, fire load of fire disaster.AS a result, evaluation conclusion correspond with the actual situation.

Abstract:Land use/land cover change in upstream of Zhanghe river basin was affected by natural and human factors. During the past decades, reduced natural rainfall and frequent human activities has an influence on this region, so this research is important. Through analyzing the spatio-temporal characteristics of dynamic change of land use/land cover change in basin, Land use/land cover change for many years will be extracted in zhanghe river basin ,using the method of ENVI change detection and ArcGIS Spatial analyst, based on 1993,2006,2010 images derived from Thematic Mapper (TM) imagery .Moreover,Spot-5 image derived from 2011,will be used for precision evaluation. These results provide an important statistic reference for land use planning and sustainable development in this region. Finally, results indicate that forest, buildings and water was respectively increased by 656.8km²、72.01km²、23.53km²,rather cultivated and barren was decreased by 411.23 km²、341.11 km²,from 1993 to 2010.The input forest area was mainly originated from farmland and barren. Part of the farmland was transformed into urban land.

Abstract:At the need of ecological restoration of subcritical flow such as polluted pool, the characteristics, purification principle and operation monitoring indexes of the carbon fiber artificial plants technology are presented. And the current pollution condition of Zhaoyuan pool is analyzed. By the treatment of the microorganisms lived at the artificial plants, the ecology of Zhaoyuan pool is to be restored. An in-situ experiment was conducted to determine optimal running density of the artificial plants. As a result, the optimal running density is 16/m². At this situation, the removal rate of CODcr , NH3-N, TN, TP were 69.16%, 81.06%, 72.92%, and 47.36% respectively. Because of the high efficiency and having no undesirable impact on the ornamental value of pools, the technology of carbon fiber artificial plants can be widely used in the future.

Abstract:In the processes of ocean numerical simulation, with the increase in the calculation domain as well as the requirement of higher accuracy, a dramatic amount of data output make the I/O efficiency become a bottleneck of the whole system performance. To solve this problem, the parallel I/O technology was used in this study to optimize the output module, and the comparison with the traditional serial I/O methods under various numbers of computing nodes and various computing scales was conducted. Experimental results demonstrate that the proposed method significantly reduces the execution time of output module.

Abstract:A landslide lies in?the upstream of dam site at the right bank of Yalong River. Once the landslide is damaged. It will have an import an impact on the local residents and safe operation of the preparing hydropower station.This paper based on the field engineering geological mapping, drilling and laboratory test, the stability is analyzed by the numerical simulation using three-dimensional finite difference software(FLAC3D).It analyzes the basic characteristics, formation mechanism and stability of the landslide. The result shows that the landslide is a oversize rock?landslide. Its formation and evolution has passed three stages: shear peristalsis, flexural slumping?and transfixion failure. The landslide is stable under natural state and lacked of stability in ,but secondary sliding may occur on local surface.

Abstract:Through the shear test and the confined compression test, this paper studied the change rule of the shear strength of soil, cohesion, friction coefficient and confined compression test of void ratio, compression coefficient and compression modulus under the condition of same dry density and different moisture content. Results show that with the increase of moisture content, the shear strength linearly decreases, and cohesion and friction coefficient decreases, which can be expressed by logarithmic equation. Void ratio, compression coefficient and compression modulus changes significantly, but the sensitivity is different.

Abstract:Combining the advantages of the limit equilibrium slice method and finite element method, the stress distribution on the sliding surface is concluded from the analysis result of finite element method. Through simple transformation, the normal stress distribution on the sliding surface can be obtained which could be used as initial stress on the sliding surface of slope. Then two unknown parameters were introduced to make correction for the normal stress which will led to the unknown parameter and safety factor of slope by substituting revised normal stress on the sliding surface into limit equilibrium equations and several simple iteration. By comparing the stability calculation results of the method introduced and other normal methods in specific engineering, the feasibility of the introduced method is verified.

Abstract:Coal-accumulating environments characteristics and coal-forming model of Pinghu Formation (Paleogene) in Xihu Depression have been studied using the drilling data and core data in this paper.The coal seams of the Pinghu Formation in Xihu Depression were formed in peat swamps of supratidal zone and intertidal zone of tidal flat facies, peat swamps of the tide-dominated delta plain and the braided river delta plain. Considering the coal-accumulating environments and the paleostructure effects, the tidal flat-delta coal-accumulating model for Xihu Depression of Pinghu Formation is established. The coal accumulation in the tidal flat and the tide-dominated delta are better than in the braided river delta. The distribution of coal-forming sedimentary system is gradually spread from the lower member to the upper member of the Pinghu Formation. The west slope of the depression has a stronger coal accumulation effects than the east fault-terrace belts of the depression.

Abstract:As the Mississippi River Delta for example, the author with the help of Google Earth software, put the delta into digital for analysis, and got some parameters such as depth and geomorphology. Combining with the geological sedimentary background and well logging curve, the author analyzed the characteristics of sedimentary subfacies and microfacies units of the delta. The study found that the sedimentary microfacies and subfacies of the Mississippi River delta both developed well, the continuity in transverse and longitudinal was better. The Mississippi River delta is a typical bird foot delta, which mainly influenced by fluvial factor. The deposits between tributary bay only developed on a large scale in the delta front of the bird foot delta, and also developed a lot of mouth bar. The shape of sheet sand in front mouth bar front was ligulate.