Numerical modeling of geothermal groundwater flow in karst aquifer system in eastern Weibei,Shaanxi Province,China

The quantitative assessment of geothermal water resources is important to the exploitation and utilization of geothermal resources. In the geothermal water systems the density of groundwater changes with the temperature, therefore the variations in hydraulic heads and temperatures are very complicated. A three-dimensional density-dependent model coupling the groundwater flow and heat transport is established and used to simulate the geothermal water flow in the karst aquifers in eastern Weibei, Shaanxi Province, China. The multilayered karst aquifer system in the study area is cut by some major faults which control the regional groundwater flow. In order to calibrate and simulate the effect of the major faults, each fault is discretized as a belt of elements with special hydrological parameters in the numerical model. The groundwater dating data are used to be integrated with the groundwater flow pattern and calibrate the model. Simulation results show that the calculated hydraulic heads and temperature fit with the observed data well.     

烟台冷流强降雪天气预报指标统计分析

通过对1971-2000年期间发生在山东半岛北部（烟台）的冷流强降雪天气过程统计分析，得出了冬季不同月份的冷流强降雪天气预报指标，为预报冷流强降雪提供了依据。     

Suitability analysis for topographic factors in loess landslide research: a case study of Gangu County,China

Loess Plateau is one of the ecologically fragile regions in China. It is one of the slippery strata of which landslides often developed. The formation and development of landslides are mainly affected by various natural environments, triggering factors, the vulnerability of landslide-bearing bodies, and topography has a controlling effect on landslides and determines landslide distribution. As important environmental elements, the selection and reclassification of topographic factors are the basis for loess landslide vulnerability map. In this study, our research suggests an effective workflow to select and analyze the topographic factors in the loess landslides. Nine hazard-formative environmental factors [e.g., slope, aspect, slope shape (SS), slope of slope (SOS), slope of aspect (SOA), surface amplitude (SA), surface roughness (SR), incision depth (ID) and elevation variation coefficient (EVC)] are prepared for landslide suitability analysis. The models of certainty factor, sensitivity index and correlation coefficient are combined to select and analyze the suitability of these factors. Four topographic factors (i.e., slope, SOS, SS and SR) were ultimately selected to carry out the landslide vulnerability mapping with other factors. Our results showed that most of the landslides were located in medium and high classes and accounting for 75.3%, and these places also coincided with higher economies and intense human activities. Our research also suggested that in situ measurements are necessary to determine how to reclassify these topographic factors and how many grades these topographic factors divided, which would further improve the reliability of landslide vulnerability map for the decision makers to deal with the possible future landslides in terms of safety and human activities.     

川东及其周缘地区下寒武统龙王庙组沉积相

通过野外露头、钻测井、三维地震及区域地质调查等资料的综合研究发现,川东及其周缘地区下寒武统龙王庙组岩石类型以碳酸盐岩(粉晶白云岩、颗粒白云岩、泥晶灰岩和颗粒灰岩)为主,局部发育大套蒸发岩(膏岩和云质膏岩)及碳酸盐岩与碎屑岩的混合沉积;识别出局限台地相、开阔台地相、蒸发台地相和混积台地相4种沉积相类型,以局限台地相最为发育;川东及其周缘地区龙王庙组各沉积相带呈北东—南西向展布,混积台地相分布于研究区西北部,蒸发台地相集中发育在研究区西部华蓥山断裂东侧,局限台地相分布于混积台地相以东到盆地东边界以西的地区,开阔台地相分布于局限台地相以东到广海的部分地区。     

兰坪金顶蜂子山铅锌矿床的构造控矿:来自三维空间数据分析的证据

滇西金顶超大型铅锌矿床的热液成矿和构造控矿特点突出,对其主要容矿岩石和断层耦合控矿机制仍不清楚.利用三维空间数据分析方法,对代表性的蜂子山铅锌矿床开展了矿化结构及其空间展布特征的综合研究.结果 表明:Pb和Zn矿化中心呈现出东西向分带及差异性分段富集的特点,空间上并与黄铁矿、天青石(—重晶石)和石膏矿体共置;成矿流体的运聚受近SN向逆冲断层和近EW向走滑断层的共同控制,为其提供通道和沉淀空间;而金顶群(N1j)的湖相氧化性含矿卤水在两组方向断层的联合驱动下,在三合洞组上段(T3S3)地层中与其赋存的还原性流体幕式混合成矿,是该矿床发育的重要机制.尤其是,近SN向逆冲断层和近EW向走滑断层联合控矿特征的发现,为深入理解金顶超大型铅锌矿床成矿作用及指导找矿勘查提供了新的依据.     

Effect of salt solution on the optimum lime contents of bentonite and silt

Acta Geotechnica - In practice, prior to treating a soil with lime, the optimum lime content required for the cation exchange and for providing sufficient Ca2+ and high pH for pozzolanic reaction...     

Changes in microstructure and water retention property of a lime-treated saline soil during curing

Acta Geotechnica - This study aims at investigating the lime treatment effect on the changes in microstructure and water retention property of compacted saline soil, with consideration of the...     

Mineralogical compositions of fault rocks from surface ruptures of Wenchuan earthquake and implication of mineral transformation during the seismic cycle along Yingxiu-Beichuan fault,Sichuan Province,China

Mineralogy and Petrology - There are two co-seismic bedrock surface ruptures from the Mw 7.9 Wenchuan earthquake in the northern and central parts of the Beichuan-Yingxiu fault, Sichuan Province,...     

近30年北京气候舒适度城郊变化对比分析

利用北京市城郊20个气象观测站1981—2010年30年气象资料,计算了20个站点的逐日舒适度指数,并统计了北京城郊夏季最热舒适度、冬季最冷舒适度的年平均值以及炎热日数、酷热日数、寒冷日数和严寒日数,最终分析给出了北京舒适度的年际和空间变化特征以及城郊舒适度差异。结果表明：20世纪80年代,北京夏季最热舒适度在炎热标准以下,城郊差异不大;90年代至今增热趋势明显,炎热和酷热日数显著增多,特别是平原地区炎热和酷热日数分别增加到40天和8天,且炎热和酷热日数空间分布范围不断扩大,2000年后扩大到除朝阳区东部以外的大部分主城区。相比较郊区而言,城区的热舒适度指数和变热幅度大,山前平原比山区热。且城区的冬季暖于郊区,寒冷和严寒日数也低于郊区,这种差距从80年代中后期逐渐明显,最大差距一年能达到10~20天;90年代后严寒区域范围逐渐缩小,平原地区的寒冷日数较80年代平均减少10天。