Abstract:Pisha sandstone area in the Yellow River Basin is a region with severe ecological degeneration in northern China. The soil erosion control in Pisha sandstone areas has long been one of the difficult problems for many soil and water conservation scholars. The difficulty lies in the alternating occurrence of multiple composite erosive forces such as water, wind, freeze-thaw, and gravity. In addition, the evident space-time separation of erosion and the complex of erosion lithology mechanism and erosion dynamic process in Pisha sandstone areas which has climate characteristics of drought, lack of water and the concentration of heavy rain, and the knowledge limitations of researchers also increase the difficulty. The research and practice progress of the soil erosion characteristics, the effects and benefits of the erosion control measures and the new technologies of controlling soil loss in Pisha sandstone areas were reviewed, and the existing problems were also proposed. The integration of erosion resistance with vegetation restoration, the combination of the Pisa sandstone utilization with the development of eco-derived industries and implementation of the ecological comprehensive treatment will be the main development aspects of soil erosion control technologies for Pisha sandstone areas in the future.

Abstract:An X-ray diffractometer and an ultra-deep three-dimensional microscope were used to determine the mineral composition and microstructure of the Pisha sandstone at different depths. The weathering characteristics of the Pisha sandstone at different depths were studied. The amount of the secondary minerals and the porosity were selected as the evaluation indicators to determine the degree of weathering of the Pisha sandstone. The experimental results show that the kinds of minerals in different depths of Pisha sandstone are the same, including quartz, feldspar, chlorite, calcite, illite, biotite, kaolinite, etc. However, the total amount of the secondary minerals is different. With the increase of depth, the secondary mineral reduces and the surface roughness of the Pisha sandstone decreases gradually. With the increase of depth, the size and number of the micro-cracks and pores are gradually reduced, the influence of the external environment become small on the weathering of Pisha sandstone, and the degree of weathering gradually decreases.

Abstract:To change the collapsing property of Pisha sandstone in water and to meet the needs for construction materials of check dams, Pisha sandstone property modification technologies were investigated. The effects of modifier with different concentrations on the swelling volume, shear strength, mineral composition and microstructure were studied by using consolidation volume and mechanical tests, XRD, TG-DTG and SEM. It shows that after property modification, the swelling of Pisha sandstone was evidently controlled and both the volume stability and the shear strength were improved. The maximum value of the volume reduction and the shear strength can be 50% and 138 kPa respectively. After modification, the spacing of the crystal layers of montmorillonite and the mass loss of the test specimen showed a significant decrease, and the hydration swelling inhibition was controlled effectively. In addition, the fracture and pore structure of the modified specimen was significantly reduced with much less cracks and smaller scales, which was more homogeneous.

Abstract:The mechanical properties of red and white Pisha sandstone with moisture content were investigated by direct shear test, X-ray diffraction and electron microscope analysis. The particle size distribution, mineral composition and micromorphology of Pisha sandstone were observed, and the influence of structural characteristics of Pisha sandstone on shear strength was also discussed. The results show that moisture content has different effects on the shear strength of red and white Pisha sandstone. The shear strength of red Pisha sandstone increases first and then decreases with the increase of moisture content dominated by the cohesive force, and the shear strength of white Pisha sandstone decreases with the increase of moisture content dominated by the friction and bite force. The main minerals of red and white Pisha sandstone are quartz, feldspar, montmorillonite and calcite. The easy weathering of feldspar, easy water expansion of montmorillonite, and the easy decomposition of calcite lead to the poor mechanical properties of Pisha sandstone. The white Pisha sandstone is composed of coarse sand and a small amount of fine sands. The particles have obvious edges and large pores, which lead to strong friction and bite force among the particles. The red Pisha sandstone is mainly composed of fine sand, and the structure is more compact, so in the sliding process, cohesion is the dominant factor, and the frictional action is less important.

Abstract:Double mass curve(DMC)method and rating curve method were applied to explore the loop characteristics of the suspended sediment concentration based on measured daily discharge and suspended sediment runoff from 1960 to 2015 of Huangfuchuan Basin in the midstream of the Yellow River. The results show that the average annual runoff and the mean sediment runoff was 111 million m³ and 31 million tons respectively. Significant reduction tendency was revealed with a reduction rate of 0. 0331 billion m³/a and 0. 0101 billion t/a, respectively. 1979 and 2003 were two turning years, exhibiting distinct phase characteristics. In addition, the rating curve can be fitted with a power exponent function and the relation between discharge and sediment does not show significant deviation. Vegetation recovery together with soil and water conservation projects play an important role in sediment reduction. Finally, there are 5 patterns of Concentration-Discharge(C-Q)relation loops for typical hydrological events, including clockwise, counterclockwise, figure-eight, reverse figure-eight and linear loops, which describe different sediment transport features during a flood.

Abstract:The correlation between two hydrology randon variables with arbitrary distribution functon is distinguished. The characteristics of correlation between two hydrology randon variables with the normal distribution function are analysed. Thefundamentals of Copula function and deformation function ditermined binarry distribution runction between two hydrology randon variables are discussed. The natures of Copula function method and deformation function method are pointed out. Finally, applications of binary distributon function in in terpolation and extension of data, probability hydrology forecasting, frequency analysis of inconsistency sample, risk probability of water engineering, design flood, geomorphologic instantameous unit hydrograph etc. are dissected and prospected.

Abstract:To evaluate the water quality in the middle and lower reaches of the Guo River, the spatial and temporal distribution characteristics of phytoplankton were quantitatively analyzed using species dominance and diversity indices methods based on four measuring data samples of phytoplankton and water quality from December 2016 to September 2017. The results show that the phytoplankton distributed unevenly in the main stream and differed greatly among different river sections. A total of 7 species and 89 genera of phytoplankton were found in the Guo River, in which Chlorophyta and Bacillariophyta were the main species. Furthermore, the dominant species of phytoplankton varied greatly with the seasons. A total of 16 dominant species were found in the four samples and those of Chlorophyta were the most in all four seasons. Shannon-Wiener diversity index evaluation grade reflects that the overall trend of water pollution was gradually improved. In addition, redundancy analysis results display that the environmental factors explained 60. 02% of the overall variation in spatial and temporal distributions of the phytoplankton. Moreover, temperature, conductivity and total phosphorus were the main environmental factors affecting spatial and temporal distributions of phytoplankton in the middle and lower reaches of the Guo River.

Abstract:The development history of effectiveness assessment and monitoring technologies for global fish passage facilities were reviewed. The main contents and monitoring technologies of effectiveness assessment were summarized and the design, operation and management of fish passage facilities were discussed. Monitoring technologies and applications of fish passage facilities both at home and abroad were compared, and combined with the practice on the monitoring and assessment in China, the guidance of oversea regulations and practice on the design, operation and management for China were analyzed. The operation effects of established fish passage facilities in China were discussed and the development directions for effectiveness assessment were pointed out. Finally, recommendations were proposed, including strengthening the monitoring technology research on fish passage facilities, implementing effectiveness assessment and monitoring in due time, and compiling technical specifications for the operation effect monitoring technologies.

Abstract:According to the characteristics and development trend of pipes and safety protection of water transfer engineering, the application advance and the main achievements of various pipes and safety protection technology of long distance water transfer pipeline engineering in Xinjiang were summarized and reviewed, combined with the special conditions of extremely cold, frequent earthquake, multiple sediment and complex erosion in Xinjiang. The problems existing in safety technology of water transfer pipeline were analyzed. The main factors considered in pipe selection and the technology development trend of water transfer engineering were proposed. Proposals for future development were also put forward.

Abstract:In order to solve the problems such as weak linkage between construction schedule and cost, lack of effective monitoring on schedule and cost during construction, difficult to find the deviation and adjust construction plans in time, this paper introduced a method which applies BIM technology and improved earned value method to construction schedule-cost joint control of RCC dams. By establishing a 3D model of the dam, using Primavera 6. 0 software to prepare a construction schedule and calculate the construction costs, and importing construction schedule and cost information into Navisworks software, the relevance matching of the 3D model and the schedule-cost information was realized. Also a 5D construction schedule-cost information visualization model and a dynamic joint management platform based on BIM during construction period was established. Secondary development plug-ins based on C#. NET and API interface can realize analogue simulation of the schedule-cost and visual information query at any time such as construction appearance and schedule, cost, resourceallocation, pouring strength of the placing unit. Monitoring the dynamic changes of improved earned value indicators, early warning during construction and adjusting construction plans can realize schedule-cost joint control during the construction. The engineering application verifies the practicability and superiority of the technology, which possesses the value of popularization.

Abstract:To study the variation law of the leakage and seepage drop due to the deterioration of water sealing in the vertical joints, a concrete face rockfill dam(CRFD)was taken as an example to simulate the seepage in the vertical joints on the left bank of the face slab, the vertical joints in the middle of the face slab, and the middle sag of the face slab under different elevations in the process of water sealing deterioration based on finite element method. The leakage through the face slab, the leakage measurement value of the measuring weir and the distribution of the seepage surface were calculated and the relationship between seepage gradient and the measured value of the measuring weir behind the dam was analyzed. The calculation results show that the measured value of the weir can reflect the deterioration degree of the water sealing in the vertical joints of face slabs and it can also estimate whether the seepage slope in the cushion zone exceeds the allowable value. With the deterioration of the water sealing, the leakage caused by the vertical joint in the middle of the panel increases, and the rise of the seepage line is more evident than that of the left bank. In addition, with the decrease of elevation, the leakage caused by the vertical joint in the middle of the panel increases, and the rise of the seepage line is also obvious.

Abstract:In order to improve the current data mining method of the dam safety monitoring database which runs slowly and takes up a lot of computational space, a modified FP-growth algorithm was proposed. The pre-processed monitoring data was pruned, and then frequent item mining was performed after the Priority tree was generated. In the application of exploring the correlation between dam deformation and water temperature and other environmental quantities, the proposed method not only has high mining speed, high precision, and simple results, but also can compare a single factor or analyze the relationship between multiple factor coupling with target variables. The example shows that the improved FP-growth algorithm provides a good idea for dam safety monitoring data mining.

Abstract:To explore the characteristics of the support structure for a folding hydraulic lifting dam during operation, combined with a practical project, the stress change laws after reinforcement under different opening angles were analyzed by FEM. Also, the effects of sediment deposition height in front of the dam on the support structure were analyzed. The results show that under the pressure of actual overflow head which led to the destruction of hydraulic lifting dam, the maximum value of the principal stress in the folding strut first increases and then decreases with the increase of opening angle. The most dangerous working angle is 45°. As the opening angle increases, the maximum value of the principal stress in the support seat first decreases, then increases, and decreases at last. Its most dangerous working angle is 0°. At the opening angle of 45°, the average tensile stress in the anchor bolt reaches the peak of 59. 46 MPa. At the opening angle of 0°, the average shear stress in the anchor bolt reaches the peak of 75. 56 MPa. The average stress is lower than that before reinforcement, indicating that the support structure is safe and feasible. The sediment deposition before the dam mainly has an adverse effect on the stability of the folding support structure.

Abstract:The association rule algorithm was introduced into the prediction of seepage behavior of earth-rock dams, and a prediction model was established. Firstly, the seepage flow, upstream water level, rainfall, downstream water level, etc. were formed into a transaction group. Secondly, the K-means algorithm was used to preprocess the measured data, and then the Apriori algorithm was used to mine the frequent item sets, resulting in strong association rules. Finally, strong association rules were used for the prediction of the seepage flow. This model can better explain the intrinsic reasons of the seepage variation. The prediction model was applied to a certain earth-rock dam project, and the results show that the model has good accuracy.