Abstract:In this paper, the simplified algorithms for quantitative calculation of drought resistance capacity are proposed under two kinds of commonly used data conditions: (1) available monthly runoff data and corresponding monthly or annual water supply-demand data, and (2) available monthly runoff data and water supply-demand data with different guarantee probabilities (50%, 75%, 90%, 95%, 97%, etc. ) for water resources planning. The drought resistance capacity is determined based on the relationship between the level index of drought resistance capacity and inflow frequency. A calculation example is given, which can provide references for further study and applications.

Abstract:The same-frequency area composition method was used to analyze the area composition of a design flood of the dam site of the Xiaonanhai Hydropower Station. The flood routing in the river reach of the dam site was simulated with the artificial neural network model, and the influence of the flood control operation of the upstream cascade reservoir group on the design flood of the Xiaonanhai Hydropower Station in different typical years was analyzed. The results show that the flood control operation of the upstream cascade reservoir group has a significant influence on the design flood of the Xiaonanhai Hydropower Station, especially on the reduction of rare floods. The floods that mainly come from the Jinshajiang River are greatly influenced by the flood control operation, while the floods that mainly come from the Minjiang River are not significantly influenced by the flood control operation.

Abstract:The inhibiting effects of immobilized photosynthetic bacteria on Microcystis aeruginosa were investigated in this study. First, through comparison of five immobilization methods and their features, the optimal immobilization method was determined. Then, photosynthetic bacteria and Microcystis aeruginosa were co-cultured through laboratory experiments. After the experiments, the impacts of immobilized photosynthetic bacteria and mobile photosynthetic bacteria on the growth of Microcystis aeruginosa were studied, and the optimal dosage of immobilized photosynthetic bacteria was determined. The study results show that the optimal method for immobilization of photosynthetic bacteria was to mix zeolites, calcium carbonate, and sodium alginate. The immobilized photosynthetic bacteria had a significant inhibiting effect on Microcystis aeruginosa, with an inhibition rate of 83.55%, while the mobile photosynthetic bacteria, at the same amount, had an inhibition rate of only 26.81%. The optimal dosage of immobilized photosynthetic bacteria was 36 g/ L.

Abstract:In order to study the effect of dynamic properties of discontinuous interfaces on mass transfer of volatile pollutants, a transient three-dimensional coupling transport model was developed based on the VOF method. The chemical reaction was ignored in the coupling transport model. With consideration of the large difference between water density and gas density, an entirely limited differencing scheme was developed. The computational results of mass transfer in an ethanol solution agreed with the experimental results. The degree of the discontinuousness increased with the initial energy of water flow blocked by barriers. Such an increase enhanced the mass transfer of volatile pollutants at the water-gas interface. Water waves with high frequencies dragged the transportation of pollutants in the air. The fluctuation frequency of pollutants increased spatially with the increase of the degree of the discontinuousness.

Abstract:Through a large-scale triaxial test, a new type of nonlinear K-G-D constitutive model, which can describe the strain softening and dilatancy of cemented sand and gravel (CSG) material, was developed based on the K-G constitutive model. The bulk modulus, shear modulus, dilatancy modulus, and other important parameters of the model were determined according to the test results and regression analysis. The nonlinear K-G-D constitutive model was verified. The results show that the calculated values agreed with experimental data, indicating that the model can provide references for the design and analysis of dams with CSG materials.

Abstract:A feasibility study of the indoor test of the Yunnan laterite landslide was carried out under simulated rainfall conditions. In the study, the modeling material, the Yunnan laterite, was used to make lateritic slopes, and the effects of the size of the slope, the lateritic properties, the molding method, and the rainfall level were all considered. The tests results show that, the success rate is low if a laterite is directly selected for the indoor test. However, a lateritic slope landslide may occur if the test conditions are well controlled. Under the conditions of indoor rainstorms, the sliding process of the lateritic slopes can be divided into the following stages: the formation of the slope, the implementation of rainfall, the formation and development of the sliding surface, and the overall slide. The sliding characteristics can be expressed as cracking and sinking on the top of the slope first, and then cracking and extension on the sides of the slope. The conditions for sliding include larger values of the height and angle of the slope, a moderate width of the slope top, a lower plasticity index, a lower dry density, a moisture content of approaching the plastic limit, the stacked molding method, and a rainstorm.

Abstract:This study focused on the Malan loess on the Longdong Plateau. A field experiment was conducted in order to study the capillary rise, and the rate of capillary rise in the loess was obtained. According to Terzaghi's theory and the estimation method proposed by Lu and Likos, the rate of capillary rise in the loess was calculated on the basis of the unsaturated soil-water characteristic curve, and was compared with the experimental value. The results show that the value obtained by Terzaghi爷s theory was larger because the permeability coefficient at the wetting front was presumed to be a saturated permeability coefficient. In contrast, the value obtained by the Lu and Likos method, which considered the unsaturated permeability of soil, had high prediction accuracy. It can therefore be used to estimate the rate of capillary rise in the loess if there is no access to a field experiment.

Abstract:A single-point GM (1,1) model was expanded into a multi-point mode1 with consideration of the correlation and interaction between multiple points. The self-adaptive MGM (1,n) model, was used for modeling and prediction of multi-point deformation, coded in Matlab. The model was applied to the prediction of deformation of the Wangxia Rock, which is an unstable rock. The results show that the predicted values agreed with the measured values, and the model had better effects, higher precision, and more accurate results than the traditional GM (1,1)model in predicting the deformation of unstable rocks.

Abstract:Within the framework of the Cosserat continuum medium mechanics model, the spherical micro particle is extended and transformed into a square micro particle with consideration of the dipole effect of material points. Based on the Cosserat continuum medium mechanics model, a linear elastic relationship between the couple stress and the curvature strain for the square micro particle is derived, and a generalized yield criterion that can consider the overturning failure of micro particles is put forward. With the finite element analysis program based on the Cosserat continuum medium mechanics model, a numerical simulation was performed in order to analyze the concrete specimens under uniaxial compression and the soil slope stability. The results show that the dipole effect of material points indeed exists, and it is a direct cause of strain localization of materials.

Abstract:It is difficult to obtain the analytical solution of a nonlinear consolidation partial differential equation. In order to solve this problem, the consolidation time is segmented into small intervals and the parameters of soft soil and stone columns are assumed to be constants at any time interval. Then, the governing consolidation equation of the stone column composite foundation is built and solved at each time interval. The calculation parameters and initial conditions of the computing unit can be determined by the calculation results of a previous time interval. Finally, consolidation calculation is conducted for the composite ground, with consideration of the nonlinear characteristics of the stone column and soft soil. On this basis, the nonlinear consolidation properties of composite ground are analyzed. The results show that the consolidation rate of the stone column composite ground decreases with the increase of Cc / Ck.

Abstract:The finite element method (FEM) was used to study the deformation, pore pressure, stress, and bag tension of a soilbag under vertical loads. The soilbag was composed of the soil modeled by a modified Cam-Clay constitutive relationship, and a woven bag modeled by a modified two-node beam element. The simulation results show that the largest horizontal displacement occurred on both sides of the soilbag, while the largest vertical displacement took place on the surface of the soilbag. The pore pressure increased initially, and then decreased with the increase of loading time. In addition, the average tension of the bag was approximately linearly correlated with the loads.

Abstract:Two long-period seismic waves with abundant long-period information were selected from earthquake records databases from all over the world. The frequency and spectrum characteristics of these two seismic waves were investigated with the orthogonal HHT (Hilbert-Huang transform) method, and compared with those of two commonly used seismic waves. A complex high-rise building was selected as a case study, in which a finite element model was established with the ANSYS software, and nonlinear dynamic response analysis was conducted on the complex high-rise building with the four seismic waves mentioned above as an input. The results show that the complex high-rise building has different effects in filtering seismic waves, and it can filter long-period seismic waves significantly. In addition, the structure's seismic response to long-period seismic waves is greater than it is to common seismic waves, and the displacement response is more significant than the acceleration responses.

Abstract:with electro-migration of N,N'-dimethylaminoethanol and the electrochemical corrosion properties of the steel reinforcement was investigated through a comparative experiment, in which N,N'-dimethylaminoethanol was used as a corrosion inhibitor. The results show that the combined remediation technology can more quickly transport the inhibition groups into the steel reinforcement, and is similarly effective in removing chloride from the steel reinforcement, when compared with the natural diffusion of N, N'-dimethylaminoethanol and the single electrochemical chloride removal method. With the increase of the duration of current and the water-cement ratio, the amounts of nitrogen electro-migrated into the specimens and the chloride removed from the specimens increased. In addition, as the applied voltage increased, the amounts of nitrogen electro-migrated into the specimens and the chloride removed from the specimens initially increased, then remained steadily unchanged. After remediation, the steel reinforcement in the mortar exhibited a strong ability to maintain passivation.

Abstract:Composite liners are commonly used in modern landfills. The translational slide failure modes, in which the back slope of the failure surface slides along the inside of waste dump and the bottom slope slides along the liner interface, may become one of the composite failure modes. In this study, we considered the effects of leachate based on the methods for stability calculation of such failure modes. We assumed that the failure surface through the inside of the waste dump was an active failure surface. Then, we used the limit equilibrium analysis method and discussed different positional relationships between leachate levels and specific interfaces, in order to obtain the calculation methods for different situations. The results of analysis and calculation show that, when the leachate water levels rose, the failures of waste dumps changed from translational slides along the liner interface to composite failures through the inside of waste dumps and the bottom liner. In practical engineering examples, the failure and instability occurred precisely because the leachate water level was too high.

Abstract:Based on tests of a rectangular one-span simply supported aqueduct, the tuned liquid damper (TLD) effect on the aqueduct under the condition of a rigid foundation subjected to strong vibration was analyzed. The relationship between the transverse damping effect and the ratio of depth to width were studied by adjusting the water level. The test results demonstrated that water sloshing and wave breaking had a TLD effect on the aqueduct structure; the increase of the water level in the aqueduct changed the dynamic properties of the structure, causing the self-vibration frequency of the structure to decrease; during strong vibration, the TLD effect fluctuated with the change of water level; and the most significant TLD effect occurred when the water sloshing frequency was close to the self-vibration frequency of the structure.

Abstract:According to the estimation formula of flood discharge atomization, and with reference to the atomization range of major hydropower engineering projects such as the Ertan Hydropower Station, we determined the range of the flood discharge atomization of the chosen hydropower station. Based on the main properties of the structural plane of the hydropower station, we determined the potential landslide downstream the left bank of the station. Based on saturated and unsaturated unstable seepage theory, and with consideration of the function of flood discharge atomization, we analyzed the evolution of the uplift pressure on the structural surfaces of the potential landslide, and we propose three protection schemes based on the design scheme. Through comparison of the effects of the three schemes, we have selected the optimum scheme.

Abstract:In order to effectively balance the risks of upstream and downstream hydropower stations and the peak load dispatching hydropower station, and reasonably share their benefits, we considered the effects of flood regulation and the storage process of the upstream station as a cooperative risk benefit and used the least core method in cooperative games to establish a least core model of diversion risk benefit sharing under the conditions of the construction of cascade hydropower stations, in order to calculate the diversion risk benefit sharing quota. A case study shows that the sharing of the diversion system and the pumped storage hydropower station exhibited negative values due to the benefits from the water diversion and flood storage at the upstream station, which means that we need to compensate the upstream hydropower station. The sharing of expenses of all the three hydropower stations varied with the change of diversion standards.