Abstract:Based on elastic mechanics and soil mechanics theory and radial deformation coordination conditions between the anchor body outer and the surrounding rock, the distribution formulas of stress along the bonded length of pressure type recoverable anchor were derived. Compared with existing theoretical results,the formulas were proved to be more practical. The peak value and range of shear stress were analyzed with various of the ratio of the anchor body's elastic modulus to the rock-soil body's E₁/E₂ and the poisson's ratio of rock-soil body μ and anchor body's outer radius R, Results show that E₁/E₂ and R are opposite to the value of peak shear stress but positive to shear stress range while μ is on the contrary.

Abstract:Most of the analysis and calculation of soil stability is based on the formula from the two-dimensional theory, in order to solve the problem that it cannot take into account the effect of the pile hole circular arch in the space project Based on В. Г. theory and the principle of retaining wall, considering the soil arch effect on the stability of the hole wall, a calculation model for calculating the maximum hole depth of self-supporting hole wall was put forward. According to different formula solutions and the MATLAB numerical analysis software, the correlation coefficient in the model was adjusted several times. Finally a simplified calculation formula was proposed, the calculation formula and В. Г. formula solution were contrasted and analyzed. The result shows that this formula can calculate В. Г. theoretical solution for better approximation, which is more concise than the В. Г. formula, beneficial to the popularization and application, and more convenient for application in practical engineering.

Abstract:The post-tensioned steel strand and energy dissipation bars are used to a self-centering steel truss beam to dissipate energy and reduce effectively residual deformation of the structure, respectively. The theoretical value of moment capacity and stiffness at end of beam are deducted correspond to major points of its backbone of their hysteretic curve. The nonlinear mechanical properties of beam are analyzed by Open Sees. the simulation results such as moment and stiffness are very consistent with theoretical analysis results, thus the effectiveness of nonlinear analytical model is proved. The nonlinear analysis results show that the steel truss beam is capable of self-centering and energy dissipation under cyclic loading.

Abstract:Fly ash, as a kind of solid waste, attracts increasing attention in the recent years. In this paper, the stress-strain and leaching behavior of fly ash and chelating fly ash under various moisture contents were studied. According to the test results, moisture content, curing conditions have significant effects on the compressive strength, failure strain. The heavy metals leaching from fly ash can almost meet the requirement of environment. The strength of fly ash and chelating fly ash rise with the increase of curing time, while the failure strain decreases at earlier period. In the later period of curing time, the compressive strength exhibits different trend, by which the strength of fly ash in curing boxes is about 23.11 times of the chelating fly ash. Among them, the strength of fly ash increases with the decrease of water content under different curing conditions, due to the influence of pore water on the absorption and structure of compaction energy; in addition, the strength of chelating fly ash in curing boxes increases with the increase of the curing time and water content.

Abstract:In order to reduce the influence of some factors such as the electromagnetic wave attenuation and noise jamming on detection effect of GPR, a predictive deconvolution method based on biorthogonal wavelet was proposed (short for PDBW method). In the PDBW method, the biorthogonal wavelet basis with the minimum reconstruction error for detection signal of GPR was chosen, using this wavelet to decompose the GPR signals into different frequency band sub-signals, and then predictive deconvolution and other filter method were used to deal with each frequency band sub-signal in time domain, at last the results of PDBW method by reconstructing each sub-signal were get. Using the PDBW method to deal with the detection signal of experiment, the results show that, comparing with the predictive deconvolution, the PDBW method could restrain the multiple echo interference, identify the deep signal precisely, and enhance the signal to noise ratio of deep signal, thus improving the detecting resolution and the accuracy of image analysis of GPR signal.

Abstract:Based on the physical model of laboratory pull-out test,a numerical calculation model of wood bolt with the variable diameter was established by means of FLAC3D. The load transfer mechanism,the interfacial shear stress distribution,the stress field and displacement field of slurry were analyzed. The influence of anchor hole diameter,anchor diameter and anchorage length on anchoring effect were studied by the numerical simulation experiment. The results show that Q-S curve from numerical simulation is in agreement with that from laboratory pull-out test,which proves that the numerical simulation on wooden bolt pull-out process is feasible and scientific. The interfacial shear stress distribution along wood bolt with the variable diameter is uneven,and shear stress mainly concentrates among the distance of 0.1m at the top and the end of anchorage section. Structural characteristics of bolt leads to the increasing trend of shear stress near the anchor end. Furthermore,it strengthens the anchor capacity of wood bolt with comparison to regular bolt. The wood bolt with the variable diameter has the characteristics of tension-type and pressure-type bolt,and radial dilation is another feature. Compared with anchor diameter which has little impact on anchor capacity,the anchor hole diameter and anchorage length have significant influence on the pullout capacity. The formula for the ultimate pullout capacity for wood bolt with the variable diameter is proposed.

Abstract:The anti-sliding capacity is an important problem. Therefore, the model tests are used to study the mechanism of anti-sliding stability of gravity anchor under the combined loading in the sea. The results of tests show that, when a gravity anchor is used as a temporary anchorage foundation of a ship, the sliding of a gravity anchor is determined by its displacements. Based on the sliding mechanism, the slice method is proposed to analyze the anti-sliding stability of the gravity anchor. The lateral bearing capacity is calculated and compared to that obtained by the method often used and the results show that it increases about 17% which is more close to the results of model tests.

Abstract:Pipe resistance coefficients (PRCs) identification of water distribution systems (WDSs) is a process of adjusting the PRCs in hydraulic model of WDSs to make its predictions consisting with measurements. Because the number of monitoring sensors is limited in practice, the identification of PRCs of WDSs is an under-determined optimization problem. Existing methods tend to use a parametric method of pipe grouping to convert the under-determined problem to over-determined, and then solve it using GA or other stochastic searching algorithms. This paper presents a prior information based algorithm for PRCs identification of WDSs. In the proposed method, the PRCs are estimated previously according to prior information of pipe material and pipe-age, and then used as pseudo observations introduced into objective function to convert the under-determined optimization problem to over-determined one, and the Gauss Newton algorithm is utilized to solve it. Compared to existing method, the proposed algorithm avoids the non-uniqueness problem of pipe grouping; in addition, the analytic formula of Jacobian matrix of PRC is deduced for searching vector construction, which improves the calculation efficiency of parameter identification. A simple network was used to illustrate the calculation of Jacobian matrix and the construction of search vector, and a larger network was utilized to validate the practicability of the method.

Abstract:To improve the accuracy and economy of fault diagnosis, the layout method of water pressure monitoring points is proposed. Firstly, a fault diagnosis model of water supply network is designed by using Modified Fruit Fly Optimization Algorithm (MFFOA) and Kernel Extreme Learning Machine (KELM). The experimental results show that the fault diagnosis model has the advantages of fast training speed and high accuracy. Then, based on the Fruit Fly Optimization Algorithm (FFOA) and the fault diagnosis model which is proposed, a water pressure monitoring point layout method is designed. In the method, firstly a set of water pressure detection points is formed by FFOA. Then, the diagnostic accuracy of each scheme is calculated by the fault diagnosis model and the accurate and economic scheme is chosen to be the candidate optimal program. After that, FFOA algorithm is used to iterate and find the optimal layout of water pressure monitoring solution which has the best accuracy and best economic performance. Finally, the proposed method which is realized is tested by the actual pipe network data. The results show that the method presented in this paper is an effective method to optimize the water pressure monitoring points. Comparing with other methods, the accuracy and economy of fault diagnosis are improved obviously.

Abstract:When evaluating the seismic reliability of urban WDSs, most of traditional methods use the same approach to simulate the leakage and burst, which leads to inaccurate results of simulation and reliability evaluation. Considering pipe damages due to earthquake are random, this paper proposed a stochastic simulation method for seismic reliability assessment of WDSs. Specifically, the seismic damage scenarios are generated using Monte Carlo simulation, in which Poisson and uniform random number are used for determining pipe working status, and normal random numbers are used for pipe leakage coefficient generation. Pipe leakage and burst are simulated based on the emitter and pipe close function in EPANET. To improve hydraulic simulation accuracy of the damaged WDSs, the long pipes are segmented and "two-step iteration" method is introduced to solve the network in low pressure condition. The ratio of the statistical average values to normal values of nodal demand in seismic damage scenarios is used as reliability index. The proposed algorithm and GIRAFFE software are used to evaluate the performance of WDSs of an ancient town in Yunnan under VⅢ and IV seismic intensity, and the feasibility of the proposed algorithm is demonstrated by analyzing and comparing the evaluating results. Evaluation results indicate that, in addition to seismic intensity factor, the hydraulic condition has great influence on the seismic reliability of WDS. Under the same seismic intensity, the water supply reliability for areas located in high terrain or far from water resource is considerably lower than that of areas closed to the water source with main pipe being serviced.

Abstract:A series of factors, such as dosage of tobacco scrap, the solution pH of solution, the time of adsorption, the original concentration and temperature, influencing adsorption of tobacco scrap to U are investigated by means of static experiment. It takes the tobacco scrap produced during the production of cigarette as ingredient. Besides, this thesis has also adopted the FTIR, SEM and EDS to represent the tobacco scrap and has discussed the mechanism of adsorbing U (VI). The result has shown that the tobacco scrap has the best adsorption of U (VI) on condition that the temperature is 30℃, the dosage is 4g/L, the? pH of the solution is 5, the concentration of U (VI) is 25 mg/L and the adsorption time is 100 minutes. The process of adsorption fits the Level 2 Dynamic Model (R²≈1) and Langmuir Isotherm Model (R²≈1) better. The results of X-ray diffraction, FTIR, and SEM have shown that the tobacco scrap has a great capability of adsorption to U (VI), whose adsorption makes the form of its surface change. The groups that interact with U (VI) are mainly hydroxyl and carboxyl groups.

Abstract:The rainstorm frequency curve fitting is essential for the identification of storm intensity formula, the study of rainstorm frequency curve fitting with considering of experience factors was carried out, and put forward to regard the rainstorm intensity frequency curve fitting as an optimization problem, and then to solve it by the weighted damped Gauss-Newton iterative algorithm. Compared to existing methods, the proposed method introduced weight coefficients to improve the fitting precision of commonly used recurrence period in engineering, and to avoid the intersection problem of different frequency curves. The finite difference method is proposed to simplify the calculation of Jacobian matrix, and the damping coefficient was added in Hesse matrix to improve iterative convergence. Thirty-three years of rainfall data of Longyang District of Baoshan city in Yunnan Province were used as an example to illustrate and demonstrate the feasibility and practicability of the proposed algorithm.

Abstract:The damage probability and the leakage level of pipelines in different earthquake intensity were calculated according to earthquake damage evaluation model and probability theory for the reason of studying the leakage and hydraulic characteristics of water supply network in ground motion. The reduction coefficient was introduced to improve the seismic reliability analysis of the pipe section, by means of comparing with the traditional calculation method, the rationality was verified. Monte Carlo simulation technology application in the service of water supply network was developed, with considering leakage and burst of pipes as well as compiling the program, the earthquake leakage of a large-scale water supply pipeline network had been calculated. The result is consistent with those of the actual earthquake disasters and provides an effective means for evaluating the failure state of the seismic function of the water supply pipeline network.

Abstract:Tests of capillary radiant heating system in Chongqing district were carried out and indoor temperature, surface temperature of envelope in condition of three different capillary laying modes (ceiling, wall and floor) with 35℃ supply water temperature were analyzed. The experimental data indicates that in the three different conditions, when the temperature of the supply water is 35℃, the average temperature of indoor air is 16.53℃, 16.40℃ and 16.94℃ respectively and that of radiation surface is 29.21℃, 28.17℃ and 22.98℃ respectively. The largest vertical temperature difference tested is 1.76℃, 3.16℃ and 0.3℃ while the largest horizontal difference tested in the direction fall is -0.26℃, 0.59℃, -0.34℃ respectively. It is shown that the system meets the requirements of indoor temperature 16℃ in three conditions. Both the thickness of capillary structure layer and the laying mode have an directly influence on the indoor thermal comfort.

Abstract:LNG ambient air vaporizer (AAV) composed of fin tube bundle is widely used in small to medium gas stations due to its advantages in energy and economic savings. The heat transfer of the fin tube in the bundle is affected by the adjacent fin tube, which is different with the fin tube in the large space. The heat transfer difference of each fin tube in the bundle is generally neglected during the design process, which results in large error. The heat transfer performance of the fin tube bundle of AAV was investigated. The fluid solid coupled heat transfer of the fin tube bundle was numerically simulated integrally, and the mixture model and Lee model were used to solve the vaporization process of LNG. The heat transfer coefficients of the air side of the different fin tube in the bundle were obtained, and the formula of the heat transfer difference among the fin tube bundle was obtained based on the numerical results. A field test of the LNG ambient air vaporizer was carried out in a LNG gas terminal to validate the formula.

Abstract:Existing energy-saving potential evaluation methods for building occupant behavior improvement do not take occupants' diversity into consideration. This significantly decreases the accuracy of evaluation results. To address this issue, a new energy-saving potential evaluation method has been established. First, principal component analysis is used to reduce the number of influencing factors of occupant behavior. Then, a data mining technique, clustering analysis is used to classify sample occupants into different groups. At last, energy-saving potentials are evaluated in terms of different groups characteristics. This method takes both the impact of various influencing factors and the diversity of occupants into account, and thus could improve the evaluation accuracy significantly. The method was applied to evaluate the energy-saving potential of 100 graduate students' computer standby usage behavior in 3 universities in Hunan province. The results demonstrate its effectiveness and feasibility.

Abstract:Temperature and humidity were measured in two typical Huizhou dwellings in winter in order to compare the indoor thermal and humidity conditions in the Huizhou traditional vernacular dwelling with that in the modern dwelling. The indoor humidity environment and thermal comfort in different zones were also studied. The results show that the level of the humidity environment is at ‘wet’ and ‘very wet’ in the Huizhou traditional vernacular dwelling in which the relative humidity is higher than that in the modern dwelling. The daily amplitude of humidity is smaller in the traditional vernacular dwelling than that in the modern dwelling, which is considered that the indoor humidity environment is stable well. There is a strong correlation between the outdoor humidity ratio and the indoor humidity ratio with a correlation coefficient over 0.8 both in the traditional vernacular dwelling and the modern dwelling. However, only 7.36% time in the hall and 8.77% time in the wing-room are comfortable with natural ventilation in the traditional vernacular dwelling, that means that the thermal comfort is unsatisfied. To improve the indoor thermal comfort, it is supposed to apply local heating equipment.

Abstract:Complete and accurate radiation data is the precondition for using solar energy,but measured data is severely lacking. The data situation can be change effectively by establishing solar radiation area estimation model Two-stage regionalization method for solar irradiation is proposed. Clearness index and mean temperature as the first-level and second-level index of regionalization separately are employing, solar climate can be divided into 17 solar zones in China. In each zone, daily global irradiation(DGI) data of the stations without measured data will be calculated with proper regional model. Taking shaanxi province as an example to estimate province-wide 33 stations DGI data, the result shows that the amount of yearly mean DGI gradually decreases from northernmost shaanxi, northern shaanxi, guanzhong region, to southern shaanxi. The solar mapping corresponds with the principle that local latitude, climate and terrain have influence on solar radiation intensity. This result indicates that two-stage regionalization method can be used in estimating DGI.

Abstract:For solving the uneven cooling problem of VAV (variable air volume) air conditioning operation, two kinds of variable static pressure and one kind of constant pressure control strategies of VAV system were operated. The relationship of room temperature,air volume,fan frequency,maximum value position,and setting pressure valve with fan power consumption respectively were analyzed and compared. Experimental results show that in addition to the set temperature, the Indoor Aai Quality(IAQ)、relative humidity and other factors should be considered in the design of valve control algorithm for variable air volume box; When using the variable air volume air conditioning system, the room temperature should be reduced to the set temperature, then the automatic control system is opened to avoid being affected by the delay of the algorithm. As to transporting unit cooling load, the electrical consumption under constant static strategy is more 7.8% than it under variable pressure strategy which static pressure measuring point is nearing the fan. And the cooling effect of constant static strategy is poor. Under the same outside conditions, compared to variable pressure strategy with static pressure measuring point nearing the fan, the cooling effect under the variable pressure strategy with static pressure measurement point far away from the fan is better. The cooling rate is at least 14% faster. And the consumption of electricity is almost the same.

Abstract:The main control building of the substation is not only to meet the operational requirements of precision equipment, but also to meet the working requirements of personnel. The design of external shading should take into account the requirements of energy saving and daylight. In this study, a typical substation building as an example in the hot-summer and warm-winter area was chosen. The change of indoor light environment and energy consumption of this building in different shading facilities were simulated and analyzed by using energy and lighting simulation software. And the suitable range of size of the shading facilities were obtained by taking the building energy efficiency and lighting coefficient standard value as evaluation index. Finally, it is clear that the size design of the external shading of this kind of building should adopt the method of double goals optimization of energy saving and natural lighting, to change the way that outside shading coefficient as a single evaluation parameter.