长江河口青草沙水库最长连续不宜取水天数

为解决上海日益增长的用水需求, 保障淡水资源安全, 需要建设长江河口避咸蓄淡特大型水库。本文应用改进的三维长江河口盐水入侵数值模式, 采用2007和2008年10个水文站盐度资料对模式进行验证, 计算青草沙水库最长不宜取水天数。本文以径流量特枯的1978—1979年作为水文计算年, 考虑三峡工程、南水北调东线工程和沿江引排水对大通实测逐日径流量的修正, 考虑潮汐、风应力和混合等作用。根据2003年地形计算得出青草沙水库的最长连续不宜取水天数为68天, 这个水库设计的重要参数已在水库建设中采用。根据2008年地形计算得出青草沙水库的最长连续不宜取水天数为54天, 已被水库调度采用。2003年至2008年北支上段河势发生了明显变化, 导致北支盐水倒灌减弱, 因此这期间的最长不宜取水天数减少。     

Risk analysis for drought hazard in China: a case study in Huaibei Plain

In recent decades, risk management is significant to mitigate the severe status caused by droughts. As one of the primary components in risk analysis, drought hazard analysis is basic but important. In this paper, the framework of drought risk analysis and the methodology for drought hazard analysis are presented, and Huaibei Plain of China is chosen as the study area. The whole study region is divided into three parts (northern, central, and southern) by geographical factors, and a developed index named drought comprehensive Z index (DCZI) containing hydrological and meteorological factors is employed for drought hazard analysis in each area. By comparison, it implicates that DCZI is applicable for Huaibei Plain and indicates drought extent more objectively. Moreover, the results of drought hazard analysis reflect that the northern area is affected by droughts more seriously. As for the whole region, there is a great probability of severe drought. Finally, some policy recommendations on drought management are also made.     

Study on the property of apparent resistivity changes of rock samples by in situ shear and friction test

In the strip limestone mine in Guiding county, Guizhou Province the shear and frictionin situ tests of rock body were made for the three typical inclined weak bands C ₃ ¹ /C ₃ ¹ , C ₃ ¹ /C ₂ ² and C ₂ ² /C ₂ ¹ . The tests were made according to the second scheme of cuneate sample of the standards on rock mechanics test of Water Conservancy and Electricity Ministry. The changes of the resistivity in the weak band and the acoustic speed across the weak band were measured in the same time. The apparent resistivity data, obtained for 8 samples on 27 measure lines in 38 cycle tests, show that the apparent resistivity changes have rather obvious characters as follows: 1. At shear and friction stage, the change of the apparent resistivity accelerates after the yield point, and reaches the maximum of change rate and change amplitude near fracture point (except the lines with resistivity invariant); 2. On the same sample, the resistivity changes are different on the various lines and related to the location settled the lines, there are some “sensitive” location; 3. At the stage of preloading normal stress before shearing, the resistivity decreases on most lines, but on a few lines the resistivity does not changes; 4. After unloading shear stress, the resistivity could not recover completely and the hysteresis of resistiviity takes place on a few lines. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 217–223, 1993. Support for this research was received from Guiding strip limestone mine, Guizhou Organic Chemistry Factory. This research is supported by the Chinese Joint Seismological Science Foundation.     

Reliability back analysis of shear strength parameters of landslide with three-dimensional upper bound limit analysis theory

It is essential to determine the shear strength parameters c and φ on the sliding surface for stability evaluation and engineering design of a landslide. In this study, a new parameter back analysis method is proposed by combining the 2D/3D upper bound method of limit analysis and reliability theory to accurately determine the shear strength parameters for a 3D slope with a single failure surface. The proposed reliability back analysis method overcomes the shortcomings of the traditional deterministic analysis method of slope stability that cannot take into account the randomness and uncertainty of geotechnical parameters. Based on the reliability theory, two methods were studied: first-order reliability method (implemented by spreadsheet and Matlab, called spreadsheet method and constrained optimization method, respectively, in this paper) and Monte Carlo simulation. The optimized values of c and φ were obtained by establishing only one balance equation with the consideration of the pore water pressure or other complex conditions, which can solve the problem of the back analysis of strength parameters for a single 3D sliding surface condition. The correlation research showed that the negative correlation between c and φ greatly affected the back analysis results, and the reliability index values were conservative without considering such a negative correlation. A case study for the back analysis of shear strength parameters is conducted based on a practical landslide model with a broken line slip surface slope in Zhuquedong village, Luxi town, Xiangxi County, Hunan Province, China, and a suggestion for the selection of landslide cross section is presented. The results show that the back analysis results determined by the reliability theory coincide well with the survey and experimental results. The proposed method is found to be more accurate and effective in determining the values of shear parameters than that of the traditional deterministic inversion method.     

Comprehensive evaluation of ice disaster risk of the Ningxia–Inner Mongolia Reach in the upper Yellow River

The Ningxia–Inner Mongolia Reach, in the upper Yellow River, is one of the most serious reaches suffering from ice flood disaster in China. Firstly, according to its characteristics of ice condition evolution and ice disaster, the concept of ice disaster risk of Ningxia–Inner Mongolia Reach was defined, the risk factors of ice disaster were discussed, and the theory and method of “risk identification–risk estimation–risk assessment–risk management” for the ice disaster risk analysis of Ningxia–Inner Mongolia Reach was proposed. Then, the comprehensive evaluation model of ice disaster risk was established using the projection pursuit, fuzzy clustering and accelerating genetic algorithm method. Finally, the ice disaster risk grade was formulated, and the ice disaster risk of 1991–2010 for the Ningxia–Inner Mongolia Reach was evaluated in this paper. The results show that the application results were consistent with the practical characteristics of water regime, meteorological and ice condition, revealing the rationality of the risk evaluation model. This study aims at enriching and developing the theory and method for the ice disaster risk analysis and providing scientific decision basis for the ice-prevention preparedness of Ningxia–Inner Mongolia Reach, in the upper Yellow River.     

Integrated risk assessment method of waterlog disaster in Huaihe River Basin of China

Regional waterlog disaster integrated risk system, affected by natural, social, and economic systems and its combination relationship, is a complex system with certain structure and function. Waterlog disaster integrated risk results from the combined effects of regional environment, impact factors, vulnerability, and disaster-reducing capability of flood hazards in the drainage area. Waterlog disaster integrated risk system can be divided into four subsystems of hazard, vulnerability, disaster-reducing capability, and disaster conditions. Evaluation indexes are selected using fuzzy analytic hierarchy process method, and the evaluation index system is established. Then, the waterlog disaster integrated risk evaluation model is proposed based on set pair analysis method. Taking Huaihe river in Anhui Province of China as the typical area in this study, the results show that the proposed approach is able to obtain the spatial distribution characteristics of waterlog hazard, vulnerability, mitigation capabilities, and integrated disaster risk within the study area. From the quantitative point of view, identification of the areas with high flood risk can provide a scientific basis for the flood management and technical support.     

复合生物反应器处理城市污水的试验研究

为了提高城市污水的处理效率、降低运行成本,进行了复合生物反应器处理城市污水的试验研究,从曝气停留时间、有机负荷率、气水比等3个方面研究了试验运行的最佳条件和控制参数.试验结果表明,利用该工艺方法处理城市污水在有机负荷率高达2.44 kgCOD/kgMLSS*d的条件下,停留时间1.5～2 h,气水比(2.5～3)∶1,可使出水COD去除率达80%以上.该方法强化了混合液的物相传质速率.     

Study on the property of apparent resistivity changes of rock samples byin situ shear and friction test

In the strip limestone mine in Guiding county, Guizhou Province the shear and frictionin situ tests of rock body were made for the three typical inclined weak bands C ₃ ¹ /C ₃ ¹ , C ₃ ¹ /C ₂ ² and C ₂ ² /C ₂ ¹ . The tests were made according to the second scheme of cuneate sample of the standards on rock mechanics test of Water Conservancy and Electricity Ministry. The changes of the resistivity in the weak band and the acoustic speed across the weak band were measured in the same time. The apparent resistivity data, obtained for 8 samples on 27 measure lines in 38 cycle tests, show that the apparent resistivity changes have rather obvious characters as follows: 1. At shear and friction stage, the change of the apparent resistivity accelerates after the yield point, and reaches the maximum of change rate and change amplitude near fracture point (except the lines with resistivity invariant); 2. On the same sample, the resistivity changes are different on the various lines and related to the location settled the lines, there are some “sensitive” location; 3. At the stage of preloading normal stress before shearing, the resistivity decreases on most lines, but on a few lines the resistivity does not changes; 4. After unloading shear stress, the resistivity could not recover completely and the hysteresis of resistiviity takes place on a few lines.     

激光探测大气扩散参数

利用红宝石激光雷达,在烟粒形状任意(或晶轴取向任意)和烟粒成分和谱分布稳定,以及一次散射和独立散射条件下,探测了烟羽相对浓度的垂直剖面分布,从而获得不同天气条件下离烟源下风向一定距离范围内大气扩散参数σ_y和σ_z。