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231.
Wischmeier's soil erodibility factor K calculated for 10 surface soils in the Hornos area, S. Spain, is compared with 3 aspects of aggregate stability. A significant correlation is found with the percentage of particles < 100 μm after aggregate breakdown, which is used as a measure of the vulnerability of the soil to erosion by overland flow. No significant correlation exists with the number of water drops required to cause breakdown of the aggregates nor with the mean size of the shattered aggregates, both being aspects of the resistance of aggregates to splash erosion. Of the micromorphological and analytical soil properties explaining aggregate stability, only the clay and silt content and the number of closed voids are significantly correlated with the factor K. The aggregate stability of the investigated soils is mainly determined by soil properties inherited from the parent material; the stabilizing effect of pedological features is small. 相似文献
232.
233.
赞比亚卢菲利安弧中西段有大量辉长岩体发育。由于本区风化严重,辉长岩常被厚土壤层覆盖。辉长岩中的铜含量常高于其沉积围岩,易于形成铜异常。为了将辉长岩形成的异常与矿致异常区别开,有必要对土壤覆盖层下的辉长岩进行识别。作者对卡皮萨比地区的化探数据采用相关分析和因子分析进行了研究,认为铜异常与基性岩浆作用有关。根据野外地质观察、音频大地电磁测量、高精度磁法测量、槽探和钻探等工作,认为:地表砖红色土壤、高磁高阻地质体和Sc-Ti-V-Fe-Co-Ni-Cu的元素组合是识别强风化条件下隐伏基性岩体的标志。 相似文献
234.
Identification of hydrogeochemical zones in postglacial buried valley aquifer (Wielkopolska Buried Valley aquifer,Poland) 总被引:3,自引:0,他引:3
This article presents the difficulty in identifying the hydrochemical zoning of a semi-confined aquifer, characterised by
a relative small spatial differentiation of groundwater chemistry. It is shown that multivariate statistical methods can be
used for the recognition and interpretation of the groundwater chemistry distribution in an aquifer. The hydrochemical zonation
caused by both natural and anthropogenic processes was identified using factor analyses in combination with a classical interpretation
of the hydrogeological material. The interpretation of the groundwater chemistry allows both identification of the aquifer
recharge mechanism and verification of the groundwater-flow system. 相似文献
235.
A soil geochemical survey was undertaken in the cultivated region of Agia in Thessaly area, Central Greece. The objectives
of the study were to assess the levels of soil contamination in respect to average concentrations of toxic metals in the region,
to determine the associations between the different toxic elements and their spatial distribution and to identify possible
sources of contamination that can explain the spatial patterns of soil pollution in the area. One hundred seventy three soil
samples were collected and analysed by ICP-AES after digestion with a mixture of HClO4–HNO3–H2O. The study focused on eleven elements (Cu, Pb, Zn, Ni, Co, Mn, As, V, Cr, Fe and Mg) and all of them except Pb have mean
concentrations above the average global soil composition. The elements Ni, Cr, Mn and V show concentrations that according
to G.L.C guidelines the Agia soils are classified as slightly contaminated to contaminated. Factor analysis explained 84.02%
of the total variance of the data through four factors. Combined with spatial interpretation of its output, the method successfully
grouped the elements according to their sources and provided evidence about their natural or anthropogenic origin. 相似文献
236.
用抗剪强度折减系数法计算复合土针支护的稳定系数,与传统计算方法相比减少了很多假设,稳定系数的概念更加明确。该方法的计算结果与复合土钉支护实际破坏形态非常吻合,与传统计算方法的结果相差不大。 相似文献
237.
238.
Sreenivasulu Ganugapenta Jayaraju Nadimikeri Sundara Raja Reddy Balam Chinnapolla Lakshmanna Ballari Rajasekhar Madiga Nirmala K Lakshmi Prasad Tella 《国际泥沙研究》2018,33(3):294-302
Sediment from twelve stations was sampled from the Tupilipalem Coast, southeast coast of India, and the presence of a set of heavy metals was established including iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd). The heavy metals were assessed by factor analysis, the results of which showed positive and/or negative correlations among Fe, Mn, Cr, Cu, Ni, Pb, Zn, and Cd. Factor analysis also indicated that heavy metals in the sediments of the study area have different natural and anthropogenic sources. Similarly, a sediment pollution assessment was done using the Geoaccumulation Index (Igeo), Enrichment Factor (EF), and Pollution Load Index (PLI). The Geoaccumulation Index indicated that the surface sediment of the Tupilipalem Coast was extremely contaminated with Fe, Mn, Cr, Cu, Ni, Pb, and Zn. The calculation of enrichment factors showed a significant enrichment with respect to Pb, Zn, and Cd and a moderate enrichment with Cr, Cu, and Ni. The falling trend of average contents’ enrichment factors is Cd> Pb> Zn> Cu> Cr> Ni> Mn> Fe. The PLI values of the Cd show higher (>1) values due to the influence of distinct external sources like agricultural runoff, industrial activities, and other anthropogenic inputs. Ninety two percent of heavy metals under study showed the highest concentrations at station TP-5 where the Buckingham Canal and other agricultural and aquacultural effluents connect with the Bay of Bengal. This location is the second inlet which is periodically closed and it seemed that these parts of the study area are heavily affected by anthropogenic pollution. 相似文献
239.
Bulk rock geochemistry of 169 fine-grained sediment samples of the upper Cretaceous to Paleogene Gosau Group(Northern Calcareous Alps,Austria and Slovakia) from borehole and outcrop localities was performed to separate non-marine and marine deposits.Geochemical characteristics of different Gosau depositional systems,basins and sediment provenance using major-,trace-,and rare earth elements were also investigated.Geochemical proxies such as boron concentrations were tested for seeking the possibilities of paleosalinity indicators.Due to the fact that several pelagic sections are represented by extremely low boron contents.B/Al* ratios are recognized as more robust and differentiate reliably between marine(mean:160±34) and non-marine(mean:133±33) samples.Using statistical factor analysis,hemipelagic to pelagic samples from the Gieβhbl Syncline and Slovakian equivalents can be differentiated from marginal-marine to non-marine samples from the Grnbach and Glinzendorf Syncline related to terrigenous(SiCh.Al2O3,K2O,Th,Rb,Zr and others) and pelagic indicative elements (CaO,Sr,TOT/C and B/Al*).A clear indication for ophiolitic provenance is traced by high amounts of chromium and nickel.Only non-marine successions of the Glinzendorf Syncline show higher Cr and Ni concentrations(up to 250 and 400 ppm,respectively) and enriched Cr/V and Y/Ni ratios trending to an ultramafic source. 相似文献
240.
In this paper, slope reinforced with one row of piles is considered. The critical slip surface is found to be divided into two parts when the pile spacing is small, and these two parts gradually get connected with the increase of pile spacing until a clear critical slip surface is formed. The critical slip surface of the piled slope is found to be usually shallower than the corresponding slope without pile, and this result is totally different from the previous results based on the maximum point of shear force where a very deep critical slip surface is obtained. The optimal pile position for slope reinforced with one row of piles is found to be located between the middle of the slope and the middle of the critical slip surface. An optimal design procedure for the pile spacing has also been suggested in the present paper, and the procedure will help to reduce the time required for a piled slope three-dimensional analysis. 相似文献