Quantification of salt weathering in porous stones using an experimental continuous partial immersion method   总被引：1，自引：0，他引：1  

D. Benavente  M. A. Garcí  a del Cura  A. Bernab  u  S. Ord    ez 《Engineering Geology》2001,59(3-4):313-325

In this study, an experimental salt weathering simulation and porous stone durability classification are proposed. There are many laboratory tests that quantify durability against salt crystallisation weathering action. These are usually based on the total immersion of samples into a saline solution, which is not representative of the salt weathering mechanism. An experimental test based on partial immersion is suggested. This is a comparable study of weight loss and degradation of visual appearance due to salt crystallisation using, on the one hand, a standard durability test (UNE), and, on the other, the proposed durability test. The weight loss and visual appearance in our test is comparable to the degradation of building stone. The differences between weight loss data in both tests depend on the petrophysical properties: porous media and degree of coherence.

From this testing, a new durability classification as a function of dry weight loss in the partial immersion test is proposed. Four divisions of different types of materials can be made in this classification, which quantifies salt weathering action mainly in environments and mild climatic conditions.  相似文献   

川滇地震科学实验场地震目录最小完整性震级分析          下载免费PDF全文

史翔宇  王晓青  邱玉荣  袁小祥 《地球物理学报》1954,63(10):3683-3697

地震目录是地震监测预报、地震活动性等研究的重要资料.川滇地震科学实验场地区近几十年来积累了大量的地震记录,为实验场的地震科学研究提供了宝贵的数据.地震台网密度和仪器观测精度是逐步提高的,不同时期地震目录的完整性存在差异,因此进行现代仪器观测记录的地震目录最小完整性震级（M_C,Magnitude of Completeness）分析,对正确研究和认识该地区地震活动规律及其影响因素等具有重要意义.本文采用震级—序号方法、最大曲率法（MAXC,Maximum Curvature）和拟合度检测法（GFT,Goodness-of-Fit Test）分析了川滇地震科学实验场地区1970—2018年地震目录的最小完整性震级M_C值,得到了实验场地区及其内部各地震区（带）M_C值的时间演化特征和空间分布特征.结果表明,实验场地区及其内部各地震区（带）M_C值变化趋势大致为1970—1986年M_L2.0~2.6,1987—1999年M_L2.5~2.6,2000—2008年后M_L1.4~2.1,2009—2018年M_L1.2~1.9;实验场地区M_C值的空间分布大致呈现东北部和西南部较低、西北部和东南部较高的特征,其中云南最南端的澜沧—耿马区和思普区、四川西北部的理塘—木里区以及川藏交界处的金沙江带M_C值普遍较高,云南北部和四川南部的松潘—龙门山带、安宁河带、元谋区、楚雄—建水带和大理—丽江—盐源区M_C值普遍较低;强震会使M_C值出现突然升高、之后逐渐恢复的现象,其中M_C值升高程度与震级有一定相关性,并且强震导致的M_C值升高是M_C值空间和时间分布不均匀的原因之一.  相似文献   

Mapping runoff generating areas using AGNPS-VSA model     

Kishor Panjabi  Pradeep Goel  Prasad Daggupati  Narayan Kumar Shrestha  Rituraj Shukla 《水文科学杂志》2020,65(13):2224-2232

ABSTRACT

In humid regions, surface runoff is often generated by saturation-excess runoff mechanisms from relatively small variable source areas (VSAs). However, the majority of the current hydrologic models are based on infiltration-excess mechanisms. In this study, the AGricultural Non-Point Source Pollution (AGNPS) model was used to integrate the VSA concept using topographic wetness index (TWI). Both the original and AGNPS-VSA models were evaluated for a small agricultural field in Ontario, Canada. The results indicate that the AGNPS-VSA model performed better than original model. The AGNPS-VSA model predicted that only the saturated portion of the field with higher TWI values produced runoff, whereas the original AGNPS model showed uniform hydrologic response from the entire field. The results of this study are important for accurately mapping the locations of VSAs. This new model could be a powerful tool in identifying critical source areas for applying targeted best management practices to minimize pollutant loads to receiving waters.  相似文献   

Studies on Intercorrelation between Ions Co-Occurring in Precipitation in the Gdańsk-Sopot-Gdynia Tricity (Poland)     

Żaneta Polkowska  Aleksander Astel  Marzena Grynkiewicz  Tadeusz Górecki  Jacek Namieśnik 《Journal of Atmospheric Chemistry》2002,41(3):239-264

The paper presents monitoring results and environmental pollution assessment for the Gdask-Sopot-Gdynia Tricity (Poland), based onanalysis of precipitation. Precipitation samples were collected over a period of 12 months (January–December 1998) at ten locations in the Tricity. The following selected ions were determined in the samples:SO₄ ^2–, F^–, Cl^–, NO₃ ^–,PO₄ ^3–, NH₄ ⁺, Na⁺,Mg²⁺, Ca²⁺, K⁺. The results were subjected to full statistical evaluation. Values of the parameters determined were correlated with each other. An attempt was made to explain co-occurrences of certain ions and the significance of their mutual effects. Pollutant concentrations and loads in precipitation were also correlated with data on wind direction and temperature in the region.Deposition of pollutants was very high in spring due to the prevailing air circulation patterns and low temperatures. Analysis of the correlations between co-occurring ions confirmed the significant impact of the location (sea coast) on the composition of rain water. Ionic ratios in rainwater were similar to those observed for sea salt samples. In addition, heavy traffic was most probably responsible for high concentrations of various forms of nitrogen and sulphates in the vicinity of major highways.  相似文献   

新疆-甘肃北山金矿南带的成矿流体演化和成矿机制   总被引：1，自引：0，他引：1  

刘伟  潘小菲 《岩石学报》2006,22(1):171-188

北山金矿南带是西北5省区规模最大的金矿带。选择北山南带的新金厂、老金厂和小西弓金矿床，在矿床地质和岩相学研究的基础上，对脉石英的流体包裹体进行了显微温度计和激光拉曼探针气体成分测定；对石英和矿石黄铁矿的包裹体H2O，CO2和CH4进行了H和C同位素组成测定，对石英和黄铁矿分别做了O和S同位素组成测定。3个金矿床的脉石英含有富CO2＋CH4、H2O溶液以及H2O-CO2＋CH4包裹体。小西弓金矿床流体包裹体的均一化温度主要介于270℃-450℃，一部分H2O溶液包裹体圈闭了高盐度流体（16．43—18．63wt．％NaCl equiv．），大部分H2O溶液包裹体和全部富CO2＋CH。包裹体代表了中-低盐度（2．8％-13．6％）流体。新金厂金矿床流体包裹体的均一化温度主要介于210℃-346℃；一部分流体包裹体圈闭了高盐度（10．98％～14％NaCl equiv．）流体，一部分H2O溶液包裹体和绝大多数富CO2＋CH4包裹体圈闭了中-低盐度（2．9％-8．81％NaCl equiv．）流体。老金厂金矿床H2O溶液包裹体的均一化温度主要分布于141℃-400℃，含盐度介于1．4％-8．28％，属于中-低盐度流体。进行了大气降水-围岩^18O／^16O、D／H交换反应模拟。小西弓矿床早期硫化物-石英脉金矿成矿流体对应较高的水／岩比（=0．01—0．05），其^18O／^16O和D／H组成更受钾长花岗岩者控制，硫化物的δ^34S值也接近钾长花岗岩的黄铁矿者，指示热液流体围绕着钾长花岗岩的对流淋滤。成矿晚期，围绕着花岗岩侵入体的热液对流崩溃，矿区围岩内发育更大尺度的彼此分离的弥漫性流体渗透淋滤；相应地，小西弓矿床晚期蚀变岩金矿成矿流体的8D值对应低水／岩比（0．005-≈0．01），其δ^18O值变化范围较宽，受当地中元古界变质岩控制，蚀变岩型金矿黄铁矿的δ^34S值也接近中元古界长英质片岩的黄铁矿者。新金厂金矿和老金厂金矿成矿流体的δD值和δ^18O值对应的水／岩值分别介于0．004—0．01和0．007～0．02，与岩浆流体或者下二叠统哲斯群辉绿岩和英安岩围岩具有更密切的关系。新金厂金矿和老金厂金矿黄铁矿样品的δ^34S值介于-2．58‰和-6．32‰，指示S来源于下二叠统哲斯群辉绿岩、英安岩和碳质板岩围岩。3个金矿的石英包裹体CO2（δ^13C=-2．20‰--9．14‰），以及石英和黄铁矿包裹体CH4（δ^13C=013．10‰--27．40‰）不平衡；前者来源于幔源岩浆去气，后者来源于哲斯群碳质板岩或者中元古界长英质片岩中的还原碳。3个金矿黄铁矿包裹体的CO（δ^13C=-10．79‰--23．62‰）主要来源于哲斯群碳质板岩或中元古界长英质片岩中的还原碳，但是，也混合了较少的岩浆CO2。包裹体CO2和CH4δ^13C值的系统变化，也反映了从岩浆侵位和去气、流体对流，到围岩中流体大面积弥漫性渗透淋滤的演化过程。CH4介入成矿流体，导致流体不混溶和金的沉淀。北山金矿南带的形成既不同于典型的造山带型金矿床，也不同于与侵入岩有关的金矿床。我们提出北山金矿南带的成矿模式为：岩浆去气和流体对流、岩石挤压破碎、流体弥漫性渗透淋滤。  相似文献   

含碎石土壤水分入渗试验研究   总被引：24，自引：6，他引：24       下载免费PDF全文

王慧芳  邵明安 《水科学进展》2006,17(5):604-609

采用一维积水垂直入渗法测定含碎石土壤的入渗过程,分析碎石含量和碎石组成对土壤水分运动影响。对试验数据采用Kostiakov入渗公式拟合,得出反映入渗速率的拟合参数比值与土石比成幂函数关系;采用简略的Philip垂直入渗方程幂级数解拟合湿润峰随时间的变化,拟合精度高,并发现拟合参数与土石比仍成幂函数关系。采用简单相关分析碎石粒径对入渗过程影响,得出粒径2~3 mm碎石与入渗过程成显著的负相关关系,而>25 mm碎石有利于入渗。研究结果可为含碎石土壤的水循环提供重要的基础。  相似文献   

基于GIS的城区雨洪监控系统应用     

常玉奎 《北京测绘》2006,(3):54-56,33

在GIS技术支持下建立的雨洪监控系统,为及时、合理地利用雨洪,节约开支提供了很好的保障,本文介绍了雨洪监控系统的应用和工程实践中的问题。  相似文献   

北京市老城区雨洪控制与利用示范工程运行中的水质研究     

崔瑜  谢振华  许苗娟 《城市地质》2006,1(2)

以北京市老城区雨洪控制与利用示范工程为背景．对天然降雨、不同下垫面雨水径流、示范工程处理过程雨水径流以及地下水水质进行分析研究,通过示范工程对雨洪的处理利用效果,探讨雨水回灌至地下能否对地下水环境产生负面影响。  相似文献   

浅析莱芜接触交代-热液铁矿的双交代渗滤作用     

杨昌彬  宗信德  卢铁元  汪云  方传昌 《地质找矿论丛》2006,21(Z1):85-89

莱芜接触交代-热液铁矿赋存于奥陶系马家沟组碳酸盐岩与燕山晚期闪长岩的接触带及其附近.通过对各矿床有益有害组分分析,以及对成矿母岩、围岩岩石化学特征、双交代渗滤作用和围岩蚀变类型等研究,总结出"三位一体"成矿模式,进而探讨了矿体的空间分布规律及其找矿意义.  相似文献   

人工合成烃类包裹体的实验研究   总被引：6，自引：3，他引：6  

倪培  王一刚 《岩石学报》2007,23(9):2033-2038

运用 Sterner 和 Bodnar(1984)提出的愈合裂隙的实验技术,在石英中成功地合成了烃类包裹体,并对合成的包裹体进行了岩相学观察、显微温度测定及激光拉曼光谱分析等。实验揭示出除合成压力之外,合成温度、反应时间和油水比例是烃类包裹体合成时几个需要重点考虑的因素。此外,合成时加入的初始溶液盐度和酸碱度也值得进一步考虑。人工合成烃类包裹体为研究天然烃类包裹体的形成机制及测定分析奠定了基础。  相似文献