Pilot study of partial extraction geochemistry for base metal exploration in a thick loess-covered region
12
Citation
17
Reference
10
Related Paper
Citation Trend
Keywords:
Soil test
Ⅰ. RESEARCHED PROFILEIn China, the most detailed study on loess was carried out in the Heimugou loess profile located at Luochuan County, Shaanxi Province, where the loess has a thickness of 135m. According to the lithologic character, loess of this section can be divided into Pouto loess, Malan loess, Lishi loess and Wucheng loess. The layer of red clay, 15m
Lithology
Loess plateau
Cite
Citations (0)
Yili area is located in the west of Xinjiang and is an intermountane basin of Tianshan, in which the loess is widespread. Only a few studies were carried out during past decades. For this reason, there are different opinions on the origin of loess. The results of grain size analysis of loess and reworked loess show that the textural features of both are same on one side and different on the other side. Firstly, the composition of grain size of loess is similar to that of the reworked loess, but the sand particles of loess is higher and the clay particles is lower than that of reworked loess. Secondly, the frequency curve of loess and reworked loess occures to be positive normal distribution. The mode of both locates in the range of 15-30μm, but the percentages are different. The amount of loess is less than 20 %, while the maxmum percentage of reworked loess reaches 50 %. Thirdly, the sorting of loess is better than that of the reworked loess, even though both are poor sorting deposits. The skewness of loess ranges from 0. 13 to 0. 43 and most of them is lower than 0. 3. Comparied with the loess, the skewness of reworked loess is higher and the mediun size moves toward coarse side. The kurtosis of loess is medium, while peak of reworked loess is steep. In summary, the loess and the reworked loess were transported and sorted by different dynamics before the dust deposited. In addition, the depositing environments were also different. The evidences from the grain size show the loess in Yili area is a typical eolian deposit.
Cite
Citations (1)
Abstract The disintegration property of loess is the wetting and subsequent disintegration of loess in water, which is generally an important index for resistance to erosion and disintegration of wet loess slopes and foundations. In this study, a disintegration instrument is developed in this laboratory and used to study the disintegration properties of fly ash-modified loess in foundations and Roadyes-modified loess in subgrades. Disintegration tests are used to compare samples of loess modified with different amounts of fly ash and Roadyes, different water contents and different dry densities; the influence of fly ash and Roadyes content on the disintegration of modified loess is analyzed. The differences in disintegration properties between the pure loess and modified loess are compared to explore the evolution of disintegration properties of modified loess and the optimal incorporation levels of fly ash and Roadyes. The experimental results show that the incorporation of fly ash reduces the disintegration of loess, while the incorporation of Roadyes likewise decreases the disintegration of loess. The disintegration of the loess modified with the two curing agents is better than that of the pure loess and loess mixed with a single curing agent; the optimal incorporation levels are 15% fly ash and 0.5‰ Roadyes. Comparing the evolution of the disintegration curves of samples of loess with different modifications shows is a linear relationship between time and amount of disintegration for pure loess and Roadyes-modified loess. Thus, a linear disintegration model is established in which the parameter P is the disintegration rate. According to the exponential relationship between time and amount of disintegration of fly ash-modified loess and loess modified with both fly ash and Roadyes, an exponential disintegration model is established in which the water stability parameter Q affects the strong and weak disintegration of the modified loess. The relationship between the water stability of the loess (modified with added fly ash and Roadyes) in water and the initial water content and dry density is analyzed. The water stability of the loess first increases and then decreases with increasing initial water content and gradually increases with increasing dry density. When the sample density is the maximum dry density, the sample has the best water stability. These research results provide a basis for the application of loess modified with added fly ash and Roadyes.
Cite
Citations (4)