冀南黄土状土湿陷性与物性指标相关性分析及预测

湿陷系数与湿陷起始压力是评价黄土状土湿陷性的重要指标。影响黄土状土湿陷性的因素较多,包括饱和度、孔隙比、含水率、塑性指数等基本物性指标,且各指标之间并非完全独立,具有一定的相关性。本文通过定性和偏相关分析给出了黄土状土基本物性指标与湿陷系数、湿陷起始压力的相关程度,并进行了排序,确定了饱和度、湿密度、塑限/塑性指数为黄土状土湿陷系数、湿陷起始压力主要的独立相关性因素。提出了黄土状土湿陷系数、湿陷起始压力BP神经网络预测模型,选取冀南黄土状土实测数据为样本进行了训练和预测,结果表明黄土状土湿陷系数、湿陷起始压力实测值与预测值误差分别在6%、11%以内,精度较高,符合工程需要,在工程实践中具有一定推广价值。

AVC系统在华北油田冀中电网的应用研究

自动电压控制(Atomatic Votage Control,AVC)是提高电力系统电压水平和经济效益,降低网损的一个重要手段。本文首先通过对华北油田冀中电网电压无功调节现状的分析,阐述了AVC 系统建设的可行性和必要性;其次根据冀中电网的实际,提出适合冀中电网的电压无功控制策略;最后在现有调度系统(DF8003S)基础上开发出了一套适合冀中电网运行实际的AVC 系统,通过不断优化运行,最终可以取得很好的运行效果。

Exploitation of groundwater resources and protection of wetland in the Yuqia Basin

In Yuqia Basin, the climate is arid and the ecologic environment is fragile, and shortage of water resources has seriously restricted the sustainable development of local economy. In order to meet the needs of industrial and domestic water in the Yuqia Basin, numerical simulation was used to evaluate the groundwater resources and potential for exploitation. The results showed that the mathematical model and calculation parameters used were mainly in accordance with practical situation. The calculated value of the underground water level is consistent with measured value during the period of identification and validation. The total recharge of groundwater resources was 22.02×10~4 m^3/d, and the total drainage was 21.95×10~4 m^3/d at present. The Yuqia River leakage is the main supply source of groundwater. There is no significant effect on area of wetland when water source place exploited by 2.5×10~4 m^3/d at alluvial-diluvial fan of Yuqia River. After long-term exploitation, the spring flow reduces from 1.42×10~4 m^3/d to 1.01×10~4 m^3/d and wetland area reduces by 32.7% of original area. The calculation of water balance shows that it is safe to the Yuqia Basin, Da Qiadam Lake, the Mahai Basin at downstream of Yuqia River and wetland under the condition of water source place exploited by 2.5×10~4 m^3/d.

Processes of hydrogeochemical evolution of groundwater in the Guanzhong Basin, China

This paper analyzed regional hydrogeochemical evolution characteristics of groundwater with respect to hydrogeological conditions in the Guanzhong Basin, China. Coefficient variation in the subregion between the Shichuan River and Luo River of the Guanzhong Basin is larger than other subregions, reflecting the more complicated hydrogeological conditions of this subregion. The hydrochemical components and hydrodynamic conditions of this area have distinct horizontal zoning characteristics, and hydrodynamic conditions play a controlling role in the groundwater’s hydrochemistry. The relationship between ions, and between ions and TDS（total dissolved solids） can give an indication of many charteristics of grounwater such as evaporation intensity, ion exchange, and the sources of chemical components. Results indicated that for the coefficient of variation（the coefficient of variation is a statistical measure of the distribution or dispersion of data around mean. This measure is used to analyze the difference of spread in the data relative to the mean value. Coefficient of variation is derived by dividing the standard deviation by the mean）, the minimum value of pH parameters is 0.03-0.07, the minimum value of HCO3-parameters is 0.24, while the maximum is the SO42-coefficinet at 1.67. A PHREEQC simulation demonstrated that different simulation paths roughly have the same trend in dissolution and precipitation of minerals. Along the direction of groundwater flow, the predminant precipitation is of calcite and gypsum and the cation exchange of Na+ and Ca2+ in some paths. However, in other paths, the precipitation of calcite and dissolution of gypsum and dolomite are the main actions, as well as the exchange of Mg2+ and Ca2+ in addition to Na+ and Ca2+.

Numerical simulation and environmental impact prediction of karst groundwater in Sangu Spring Basin,China

The changes of development and utilization of karst groundwater in Sangu Spring Basin have made the original groundwater resource evaluation unable to meet the needs of future economic development.Based on analysis of existing data,combined with the characteristics of supplement,runoff and draining of regional karst groundwater,the Visual Modelflow software was used to build a numerical simulation model of Sangu spring Basin.The amount of karst groundwater resource and groundwater environment of the Basin were evaluated under different exploitation schemes,and the changes of karst groundwater environment in the future ten years were also predicted.The fitting error which is less than 0.5 m between the calculated value and measured value of the water level in the fitted borehole accounts for 93%.For the lithologically and structurally complex Sangu Spring Basin,the fitting effect of numerical simulation model was ideal.On the basis of the current mining amount of 111.80 million m3/a,the total redistributed exploited amount in the spring region was 61.79 million m3/a.Under the condition that the quantity of recoverable resources reached 173.59 million m3/a and under different precipitation schemes,all constraint conditions were satisfied,such as regional water level drawdown,maximum allowable water level drawdown in every simulated water source area and the flow rate of Guobi Spring.The results will provide a scientific basis for the rational development and utilization of karst groundwater in Sangu Spring Basin.