Abstract:

Abstract:Structure has a major influence on the stressstrain relation of soil, which implies that the constitutive model should reflect the its structure. Based on the investigation , the overconsolidation (OC) of the soils was made up of two different types, which were structureinduced OC and stressinduced OC. And then the structureinduced OC and stressinduced OC were united. Structureinduced OC index was used to represent the degree of structure and the cam clay model was extended. The shape of the yield surface was the same as cam clay model, whise the size was equal to the sum of the structureinduced OC and stressinduced OC. And the change in size of the yield surface was decerminated by the volumeharden function and the structural damage function. The associated flow rule was adopted in the model. Afterwards constitutive model for structured clays was presented. The concept of the model is clear and the parameters are simple. The ability of the model is good by firstly application and it can describe the character of the structured soils.

Abstract:According to the characteristics of plane strain problem of elastic and plastic mechanics, the biparametric expressions were derived for stress components satisfying the generalized HoekBrown failure criterion. Being substituted into the static equilibrium partial differential equations, a group of firstorder hyperbolic pseudolinear differential equation partial differential equations was obtained. Utilizing the determinant method and proper variable transformation, the characteristic direction and the differential relation equation for the stress partial differential equations were acquired. The characteristic direction indicted that in plastic zone obliquelyintersecting conjugate shear slip surfaces formed two families of nonorthogonal slip lines, in which conjugate angle varied with the limit stress state and the material physical properties of HoekBrown rock mass. Since the principal direction of the maximum principal stress was circumferential in perfectly elastoplastic surrounding rock of the plastic zone around a circular opening suffering the symmetric initial stress field, the angle between the tangential direction of slip line with the principal direction of the maximum principal stress was the function of the minimum principal stress(i.e. the radial stress). Combined with the analytical solution, the polar coordinate differential equation was derived and furthermore, the polar coordinate curve equation for the slip line was obtained.

Abstract:A coupling modeling method with MIDAS/GTSFLAC3D was put forward aiming at the technical difficulties and deficiencies in preprocessing for complex geologic body and structural engineering with FLAC3D. The coupling procedure was that, firstly, the threedimension geometry model was built with MIDAS/GTS and the model meshes were divided. And Secondly, the element and node data of the completed model built in MIDAS/GTS were exported. After data was transformed by using the interface program in MATLAB, the information was imported into FLAC3D. Thus the threedimension FLAC3D model for complex engineering was generated coupling with MIDAS/GTS. With coupling method, the complex threedimension model was built for Fanshuigou bridgeShipogou tunnel engineering above minedout region, and the results verified the feasibility and effectiveness of the proposed method.

Abstract:The test simulating contact explosion in saturated soil was completed in the φ2.5×5m pothole. Through the experiment, the data of the freefield in the saturated soil was obtained. The formulas of pressure, momentum and rise time with distance were fitted out based on a large number of test data. According to analysis of the test data, the spreading law of the wave in freefield of saturated soil was obtained. Theoretical analysis showed that saturated soil had the nature of liquiddynamic area appearing and shock wave forming when the stress wave spread in the saturated soil. The bilinear progressively increasingharding constitutive relation in saturated soil was established. Dividing pressure was determined and that was the value from shock wave to elastic wave. Moreover, the diving pressure related to media character was different in various soils. Because shock wave was formed easily, the structures in saturated soils had much higher risk of failure under the same explosive conditions.

Abstract:A typical clayey loess obtained along the ShenyangHa’erbin Express Railway was taken as a case study. The effect of nonsaturated water content, temperature, freezing rate, supplying water condition and freezingthawing circulation on the frost susceptibility of soil were investigated with freezing and thawing experiments. It was shown that in the closed system, the frost heaving ratio of unsaturated soil increased with water content increasing and eventually reached a stable value. And for the soil samples with low water content, the frozenheave rate increased with the decrease of temperature. While for the samples with relatively higher water content, the frozenheave rate decreased with the increase of temperature. As regards the open system, the frost heaving ratio increased with a growing gradient as the freezing rate decreased. Waterfeeding made the frost heave amount increase significantly, while less with the increase of water content. The frost heave deformation showed exponential decline trend with the increase the frequency of freezing and thawing for soil with low dry density, while exponential increase for the soil with high dry density.

Abstract:With the monitoring data of groundwater level of some reservoir slope, the nonlinearcombined model was established on the basis of establishing the time series method and speed analysis method. Upon the comparison, it was found that the precision of nonlinear combinedmodel was higher than that of single model. It was an effective prediction method for groundwater level of reservoir slope and could be employed for stability prediction of reservoir slope.

Abstract:The intense coupled and nonlinear behaviors were observed on the tall longspan towerline systems which were under the icing and wind loads in heavy icing areas. A set of stiffness equations of insulator, conductor and boundary conditions was deduced. Taking the ±800 kV UHV DC transmission line from Xiangjiaba to Shanghai as an example, the simplified numerical model of transmission tower, conductor, insulator and constraint was developed. The long span transmission towerline system models under seven loads conditions were analyzed by static nonlinear methods. It was found that the PΔ effect of tower components was small when the covered ice was uniformly distributed. The unbalanced wire loads on the tower would lead to twist effect when the covered ice was uneven distributed. The axial forces, moments at restraint nodes and the longest cantilever member were greatly affected by the PΔ effect, under which the unfavorable effect on the structure should be considered.

Abstract:Differential Evolution (DE) was introduced to get the global optimum and overcome the difficulties encountered by coupling two types of design variables in the shape optimization of truss structures with stress, geometry, and local stability constraints. The basic principle of DE algorithm was presented in detail first, and then mathematical model for shape optimization of truss structures was presented, in which two types of design variables, such as the node coordinates and section areas, were considered simultaneously. Several classical problems were solved with DE algorithm, and the results were compared with those using the other optimization methods. It was shown that DE algorithm had good convergence and stability and could be applied for shape optimization of truss structures effectively.

Abstract:Eight concrete beams reinforced with 500MPa steel bars and four reinforced with 400MPa ultrafine grain steel bars were tested under twopoint symmetrical concentrated static loading to observe the details of crack pattern development on these beams and investigate their cracking characteristics. It was shown that the cracking behavior of the beams with highstrength bars was essentially similar to that of common RC flexural members, whereas the computed crack widths using the formula adopted in the Code for Design of Concrete Structures GB 500102002 exceeded that of the experiment under the normal service. Furthermore, the formulas for crack spacing and crack width specified in GB 500102002 were evaluated through the experimental results and previous studies of sixtyseven concrete beams reinforced with highstrength bars. On the basis of the calculation model in GB 500102002, revised formulas for crack spacing and crack width were proposed. The values calculated by revised formulas were in good agreement with the test results.

Abstract:In order to study the damage characteristics and mechanism of underground water on underground structure, factors of structure deformation and cracks based on a case study had been investigated. Meanwhile, finite element method had been used to simulate the deformation and decrease of stiffness. And structure deformation mechanism had been investigated, together with cracks characteristics and the effect on the structure’s safety. It was found that the underground structure would be swollen up and floated as the float was larger than the structure’s weight. And the uptrend of boundary retaining wall was restrained by soil, which made vertical displacements in columns and concrete walls different and resulted in structure cracks and the decrease of structural stiffness. The general structural damage was depended on the plan size and controlled by the short side. And the damage was more serious in central than that in boundary.

Abstract:“Macro model” in OPENSEES is an ideal and effective method for simulating RC beamcolumn joint. Some disadvantages, however, exist in both the modified compression field theory (MCFT) and diagonal compression strut model, with which they are commonly used to obtain the shear stressstrain relation of joint core. A new method by means of strutandtie model (STM), which reflected three mechanisms in joint well, was proposed to simulate the shear stressstrain response of joint core. The deformation compatibility and equilibrium condition of the model were deduced thereafter. It was indicated that the result of STM method was in good agreement with that of test data. And it could simulate more accurately the shear stressstrain response of joint core with a wide range of stirrup ratio.

Abstract:The simplified mechanical model was proposed for framesupported multiribbed composite wall beam. And the internal force of joist was calculated with the method of beam on the elastic foundation which takes the horizontal friction resistance into consideration. Moreover, a comparative analysis was employed with FEA program. It was found that it was necessary to consider the interfacial shearing force between wall and joist for the framesupported multiribbed composite wall beam, otherwise, the performance of the composite would not exhibited sufficiently and the calculation error would be large.

Abstract:Both Three Points Bending (TPB) test on notched beams and Wedge Splitting Test (WST) were carried out on concrete specimens under six different conditions, under which they were totally dry, partially dry, water immersed, seawater immersed, 5% and 23.4% NaCl solution immersed, respectively. The fracture energy of each type of concrete and their strain softening curves were calculated according to the forcedisplacement diagrams and inverse analysis method. It was indicated that with water, seawater or salt solution penetrating into concrete, the surface tension of pore liquids in concrete increased, which resulted in the decrease of the surface energy and load bearing capacity of concrete. After water immersed, the maximum bearing loads of specimens’ were reduced by 19.6% (TPB) and 14.5% (WST) compared with those of totally dry concrete. And for those of seawater immersed, 28.9% and 21.7% were reduced respectively. Furthermore, fracture energy of concrete was decreased more than 24% and fracture toughness was reduced significantly as well for concrete with high concentration salt solution, which made crack formation in concrete easier. The adverse influence of seawater on concrete materials had been investigated in detail from the aspects of surface energy, fracture energy and strain softening.

Abstract:To investigate the mechanical behavior of reinforced concrete structure subjected to fire, the incremental thermoelasticplastic creep constitutive equations of steel and concrete in consideration of temperature and creep deformation were obtained based on different yield rules and the elasticplastic theories. The nonlinear analysis for reinforced concrete simply supported slab was carried out with consideration the variation of the mechanical properties of steel and concrete with temperature. The effectiveness and applicability of the constitutive equations were verified with the test results from relevant literature. The nonlinear analysis was employed for onebay onestorey reinforced concrete frame under fire and the variation of displacement at partial nodes was analysed. It was found that the reinforced concrete structure at a high temperature would have a significant deformation. And the displacement change curves of beamcolumn joints of reinforced concrete frame were not monotonous trend and there were inflexion points. The vertical displacement values of beamcolumn joints were less than those at midspan of crossbeam.

Abstract:In order to investigate the fire resistance of steel columns with partial fire retardant coating damage in fire, based on the differential equation of equilibrium on each portion of steel column, the deflection of steel column after the fire retardant coating damage was derived, with the pined ends and rigid ends of the columns at elevated temperatures. The critical temperature calculation method was proposed for partial fire protection damage and axial restrained steel columns by taking the edge yielding criteria. The deflection and axial displacement were verified by finite element method at elevated temperature. With a case study, the critical temperature and relationship of axial force and temperature were obtained for pined column with axial restraint. It was shown that the axial force of the steel column at elevated temperatures was increased and the critical temperature was decreased by the axial restraint. The longer the fire retardant coating damage was and the higher the axial restraint was, the lower the critical temperature was.

Abstract:Indoor thermal comfort can be significantly improved by natural ventilation with reasonable architectural design. In order to compare natural ventilation effect, the distribution of velocity field, temperature field and the PMV in different architecture layout and orientation design were analyzed with house types in Best House Type Competition. It was found that indoor natural ventilation effect was obviously improved by means of altering the layout and orientation, where the maximum velocity varied from 0.24m/s to 0.82m/s. And the temperature decreased 0.9℃ and the value of PMV was more approximate to comfort.

Abstract:Referring Seasonal Energy Efficiency Ratio（SEER）——a method for seasonal performance evaluation of room air conditioners in GB 7725, the Seasonal Temperature Effectiveness was proposed to evaluate thermal seasonal performance of a heat pipe heat recovery unit based on the annual operation data in a shopping mall. And its calculation formula was deduced thereafter. With the case study, it was indicated that seasonal temperature effectiveness of the unit was 66.08% in the winter and 55.43% in the summer, which meant that the system was efficient.

Abstract:Lighting and airconditioning energy consumption of stadium is very large. That how to use natural lighting and natural ventilation is the key pivot for stadium energy efficiency design. A variety of passive energy efficient measures were used in the Multifunctional stadium of Guangdong College of Pharmacy, such as lighting windows with vertical blinds in east and west facades, Openable windows on south and north facades, planting roof and etc. It was found that the abovementioned passive designs could 〖JP2〗increase natural illumination of competition venues, prevent the glare, raise wind speed in audience area, improve comfort level and decrease internal surface temperature of affiliated building and reduce heat radiation.

Abstract:In order to improve the deficiency of existing daylighting climate zones and investigate the characteristics of the typical daylighting climate zones, the ratio between direct light ,diffuse light , global illumiance and extraterrestrial horizontal illumiance were taken as parameters. On the basis of annual observation data of twelve typical light climates zone, daylighting climate of various regions was investigated by PGD diagram. This method could more intuitively and accurately reflect the characteristics of regions and be easier for comparing the difference between light parameters .Through analysis, the daylight distribution profile of twelve zones were obtained, with which it could be reference for daylighting design.

Abstract:Based on the hourly data of air temperature observed from automatic weather stations in Xi’an, the time series of urban heat island (UHI) intensity in the summer and winter of year 2008 were set up. Complex Morlet wavelet transform was employed to analyze the time scale (variation period) structure and characteristics of UHI. And wavelet variance was used to diagnose the oscillation intensity of UHI periods. It was found that the time scale structure of UHI was simple in winter while complex in summer. The primary UHI periods were composed of 24 h and 144192 h in winter and 24 h and 96~120 h in summer. Diurnal and weekly variations of UHI were the dominant UHI periods in Xi’an. For weekly periods, intensive UHI occurred on weekdays, while weak UHI on weekend. Moreover, the causes of the diurnal and weekly periods of UHI were also employed.

Abstract:According to small environmental capacity and fragile ecosystem of lake, the lakes in Chongqing Section of Three Gorges Reservoir Region were taken as a case. The effects of cold water discharge of lake water source heat pump systems on lake algae and Chla were studied with the method of physical simulation. It was found that cold discharge discouraged the growth of algae, and the critical temperature of algae growth was between 4.5℃ and 6.2℃. There was significant impact of cold discharge on dominant populations and its proportional change of algae. And it would reduce the number of algal populations and the content of Chla. Furthermore, the cold discharge would have great influence on total quantity of phytoplankton. And the higher the content of nitrogen and phosphorus of raw water was, the greater of the effect extent was.

Abstract:Under the microwave irradiation, a highly effective adsorptive material zeolitized fly ash (FZ) was made by adding a certain amount of mineralizer in the raw material of the limestone and fly ash. The structure of zeolite and the mechanism of modification were investigated by the analysis of XRD and SEM.The stabilization mechanism was analyzed and the variation of heavy metals and nutrient contents in sewage sludge were investigated through the sludge stabilization experiment by mixing zeolitized fly ash in the municipal sewage sludge. It was indicated that the zeolitized fly ash had obvious stabilization effect to heavy metals (Zn、Cu、Mn) and had apparent retention ability to the nutrients contents of N、P of the municipal sewage sludge. The heavy metals contents of Zn, Cu and Mn were all significant lower than those in the national control standards for pollutants in sludges from Agricultural. After the stabilization treatment of the municipal sewage sludge, the total content of N was lower than that in the national surface water environmental quality standards (10 mg/L), the total content of P was lower than that in Quality Standard of the Sewage discharged into the city sewer system(1 mg/L).

Abstract:Reaction rate of alkaline supernatant of waste activated sludge (WAS) as carbon sources for denitrification was investigated to determine the recycling dosage preliminarily. WAS was digested under alkaline conditions and batch tests were carried out under different VFA/N ratio at SRT=9d to examine the denitrification rate and choose the optimal ratio. And then a comparative test was carried out for actual sewage wastewater and pure sewage wastewater to investigate its feasibility in recycle and the recycling dosage. It was found that denitrification curve of all ratios could be divided into four stages and the denitrification rate increased obviously with the increase of VFA/N ratio, which was consistent with that of the pH curve. While as the ratio increased beyond 2.47, the denitrification rate increased slowly. Furthermore, when the supernatant was added to the sewage wastewater to some extent, denitrification rate increased significantly and the removal amount of nitrate in two parallel tests were 47.0 and 33.9 mg/L, respectively.

Abstract:The rule of preparation methods and environment factors which influence the compression sensitivity was the prerequisite of utilizing the smart properties of SSM. Experiment test was carried out for the analysis of some factors that influence the compression sensitivity, including the steel slag content, curing regime, age, water content and temperature. It was found that the compressive sensitivity of SSM increased with the increase of steel slag content, water curing time and water content. And at early age, the compressive sensitivity of SSM decreased with the increase of age and the compressive sensitivity of SSM gradually stabilized after 28d age. When the water content was between surface drying condition and air seasoning condition or the temperature was between 5 ℃ and 25℃, the compressive sensitivity of SSM kept stable. The dominant factors for the compression sensitivity were water content and temperature, followed with age, and the influence of curing regime could be neglected. The influence of environment factors on the compression sensitivity could be weaken with the increase of steel slag content and selecting the stressresistivity change rate curve based on water content and temperature of SSM.

Abstract:Manganese alloy slag is an industrial waste produced from manufacture of manganese alloy. Recent years environment pollution of manganese slag has been becoming heavier and heavier with the development of manganese industry. Aiming to sort out this problem, combination of manganese slag and ground granulated blastfurnace slag (GGBS) were applied to prepare alkaliactivated cementitious material. Compressive strength and flexural strength of cementitious material prepared with combination of alkalislagmanganese slag were measured. And microstructure of hydration production was investigated by scanning electromicroscope (SEM). It was shown that the flexural and compressive strength of cementitious material with alkaliGGBSmanganese slag system were decreased with the increase of replacement of GGBS by manganese slag. The increase of the fineness of manganese slag was favorable for strength improvement of the alkaliGGBSmanganese slag material. It was concluded that ground manganese slag had hydraulic activity in alkaliactivated cementitious material and the activity was lower than that of GGBS.