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Loess geohazards in China
Published in Yanrong Li, Jingui Zhao, Bin Li, Loess and Loess Geohazards in China, 2017
Yanrong Li, Jingui Zhao, Bin Li
The three main layers of loess exposed in China are Wucheng loess (Q1) deposited in the Early Pleistocene, Lishi loess (Q2) deposited in the Middle Pleistocene, and Malan loess (Q3) deposited in the Late Pleistocene (Tang, 2011). Lishi loess (Q2) is reddish yellow clayey soil with layered calcareous concretion, characterized by dense structure and low water permeability. Malan loess (Q3) is light yellow silt, with loose structure, large pores, dense vertical joints, and high permeability. Field investigations show that most of the loess collapses occurred in the Q2 and Q3 loess, particularly in the Q2 layer.
vd ranges and the interrelated relation with the bearing capacity of recently deposited layers in Huaibei Plain
Published in Kennis Chan, Testing and Measurement: Techniques and Applications, 2015
is the narrowest, while that of silt wider and that of sandy soil the widest. 2 There is an incremental impact of specific penetration resistance on dynamic deformation modulus, meaning Evd increases alongside with the increase of specific penetration resistance. Both elements are able to reflect the mechanical property and its variation features of soil layers containing calcareous concretion and the presence of calcareous concretion leads to larger Evd values of clayed soil layers. 3 There is a significant linear correlation between dynamic deformation modulus Evd and the subsoil bearing capacity. Di erent types of subsoil have distinctive features of the bearing capacities which are mutually diverse. Evd values give a good reflection of the bearing capacity features of typical geological bodies in Huaibei Plain and hence can be used as an index for mensurating the subsoil bearing capacity in highway engineering projects.
The Newer Volcanics
Published in W. A. Peck, J.L. Neilson, R.J. Olds, K.D. Seddon, Engineering Geology of Melbourne, 2018
Studies of residual soils developed on the Newer Volcanics of western Victoria (Jackson, et al., 1972; Mokma, et al., 1973; Dahlhaus, 1986c) have established some relationships between age and soil characteristics. In summary: - * the soil depth increases and the proportion of boulders decreases with time given to weathering.* the gravel in the younger soil consists mainly of basalt, while in the older soils and thicker soils it comprises mostly pedogenic nodules.* the amount of kaolinite plus halloysite increases with age, while the amount of amorphous material and chlorite decreases.* the particle size distribution becomes coarser with the progressive development of concretion-like, amorphous, ferruginous nodules in the top of the older soil profiles.* the quartz contents of the surface soils increased with geographic proximity to source of the quartz and the age of the basalt.* older soils have developed a distinctive profile with a friable, red-brown silty clay surface layer, becoming a very stiff, mottled yellow-brown and grey fissured clay.
In-situ test study on compaction control parameters for particular subdivisional railway earthworks
Published in International Journal of Pavement Engineering, 2021
Jianbo Fei, Jinfeng Xiao, Yuxin Jie, Kaihang Han, Changsuo Yang
Inner Mongolia-Jiangxi Railway is a heavy haul railway line with an axle load of 21 ton, and it was built as a freight-only line with a design speed of 200 km/h. This railway line is the longest railway line for coal transportation in China with annual freight volume of 2000 million ton. The construction sequence of cable troughs and drainage ditches along Inner Mongolia-Jiangxi Railway includes channel excavation, soil compaction and cast-in-situ concretion (see Figure 9(a)) or installation of prefabricated units (see Figure 9(b)). Since the cable trough along Inner Mongolia-Jiangxi Railway is 720mm wide and the bottom of drainage ditch is 400mm wide, even small compaction machineries introduced in Section 2 are not applicable. Thus, the light plate vibratory compactor or the vibratory tamper (shown in Figure 2) is adopted to compact the cable trough channel in the project. The hydraulic vibratory tamper is specially designed to be installed on an excavator (see Figure 9(c)) to compact the bottom and slopes of drainage ditches during the implementation of Inner Mongolia-Jiangxi Railway (section MHTJ-11) earthworks.
Health risk assessment of oral bioaccessibility of heavy metal in soil from coalfield in Huaibei City, China
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Liqiang Sun, Chongyu Sun, Fei Liu, Xianming Bao
The coal mine was constructed in 1985 and began exploration in 1997. The coal resource of this coal mine is abundant, as the amount of the pit output is up to 300 Mtpa. An affiliated power plant is in vicinity of the coal mine, discharging a large amount of coal fly ash to surroundings. Moreover, several coal gangue waste piles are located in the study area. Heavy metals existing in coal gangues and coal fly ash may enter into surrounding soils through wet or dry deposition, potentially causing metal pollution in soil and excessive accumulation in plants potentially. Maize (Zea mays L.) and winter wheat are one of the most dominant crops growing on the agricultural fields of this area. Soils are dominated by lime concretion black soils and moisture soil, accounting for 80% of total area.
New results of stable isotope and petrographic studies of Jurassic glendonites from Siberia
Published in GFF, 2019
Kseniia Y. Vasileva, Mikhail A. Rogov, Victoria B. Ershova, Boris G. Pokrovsky
Our data on petrographic, cathodoluminescence and isotopic characteristics of the studied samples along with records of glendonite distribution in Siberia and Northeastern Russia let us draw the following conclusions: Ikaite precipitation occurred in a shallow cold-water basin that confirms that the sedimentation of the studied strata occurred in a cold climate.Geochemical environment of ikaite precipitation was determined by presence of marine organic matter resulted in low carbon isotopic values (up to −30 ‰ PDB) estimated for ikaite-derived calcite.During diagenesis a significant volume of early ikaite-derived calcite was corroded or replaced by cement calcite that influenced greatly on the isotopic composition of the bulk glendonite concretion.