The Experts below are selected from a list of 13863 Experts worldwide ranked by ideXlab platform
Yu-jun Cui - One of the best experts on this subject based on the ideXlab platform.
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Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under Salinization-deSalinization cycle conditions
Applied Clay Science, 2015Co-Authors: Y.g. Chen, Chunming Zhu, Qiong Wang, Yu-jun CuiAbstract:Compacted bentonite has been used as buffer material in radioactive waste disposal. Once compacted bentonite is emplaced, the chemical composition of site water is changed due to the long-term interaction between the bentonite, surrounding rock and the concrete facility; therefore the hydraulic mechanical behavior of compacted bentonite should be evaluated for the disposal safety. In this study, the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite were investigated under Salinization deSalinization chemical cycles using a newly developed apparatus. Results show that the Salinization process leads a reducing of swelling pressure and the desalination process leads to an increasing of swelling pressure; the hydraulic conductivity increases in the Salinization process while decreases in the deSalinization process. The variation magnitude of the swelling pressure and hydraulic conductivity is related to the solution concentration applied. Meanwhile, the initial chemical condition and chemical cycle paths have a significant effect in the swelling characteristics and hydraulic properties. Since the Salinization-deSalinization cycle is expected to occur over a long time during the operation of the repository, the monitoring of the buffer materials will be important for the disposal safety.
Naipeng Zhang - One of the best experts on this subject based on the ideXlab platform.
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valley reshaping and damming induce water table rise and soil Salinization on the chinese loess plateau
Geoderma, 2019Co-Authors: Yunqiang Wang, Yunlong Yu, Yiping Chen, Jing Zhang, Naipeng ZhangAbstract:Abstract A megaproject, “Gully Land Consolidation” (GLC), was launched on the Chinese Loess Plateau in 2011 to combat land degradation and create new farmlands. However, the newly-claimed farmlands have suffered soil Salinization, and the mechanism of Salinization has been inadequately addressed. In this study, a creek valley that completed the GLC project in 2014 was selected and a total of 17 new farmlands along the reshaped creek valley were investigated in 2016. Moreover, the hillslope farmlands without conducting the GLC project, the loess parent material that used to fill the stream channel, and the water samples from reservoirs, irrigation wells and spring outlets in the reshaped valley were sampled and chemically analyzed. We found that the new farmlands experienced a significant rise in the water table that played a key role on soil Salinization. After GLC, >80% of the sampling sites (14 out of 17) showed a shallow depth (≤3 m) from the soil surface down to the groundwater influence zone. Moreover, the closer the downstream farmlands to the newly-built dams, the shallower the water table, indicating considerable impacts of constructing dams on the water table depth in the near-dam farmlands. At the study site, more than half of the shallow soil samples (20 cm depth) underwent light soil Salinization, and the most significant soil salinity occurred in the upper stream farmlands. The interplay between a near-surface water table, a high evaporation rate, landform features, and the alkaline properties of the loessial soil has led to the significant soil Salinization in the upper stream of the valley. To mitigate soil Salinization and ensure the sustainability of the newly-created farmlands in GLC, drainage trenches in the downstream near-dam farmlands and the drainage canals on both sides of the reshaped valley are suggested, which improve the drainage efficiency and control the water table depth.
Y.g. Chen - One of the best experts on this subject based on the ideXlab platform.
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Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under Salinization-deSalinization cycle conditions
Applied Clay Science, 2015Co-Authors: Y.g. Chen, Chunming Zhu, Qiong Wang, Yu-jun CuiAbstract:Compacted bentonite has been used as buffer material in radioactive waste disposal. Once compacted bentonite is emplaced, the chemical composition of site water is changed due to the long-term interaction between the bentonite, surrounding rock and the concrete facility; therefore the hydraulic mechanical behavior of compacted bentonite should be evaluated for the disposal safety. In this study, the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite were investigated under Salinization deSalinization chemical cycles using a newly developed apparatus. Results show that the Salinization process leads a reducing of swelling pressure and the desalination process leads to an increasing of swelling pressure; the hydraulic conductivity increases in the Salinization process while decreases in the deSalinization process. The variation magnitude of the swelling pressure and hydraulic conductivity is related to the solution concentration applied. Meanwhile, the initial chemical condition and chemical cycle paths have a significant effect in the swelling characteristics and hydraulic properties. Since the Salinization-deSalinization cycle is expected to occur over a long time during the operation of the repository, the monitoring of the buffer materials will be important for the disposal safety.
Xiangping Wang - One of the best experts on this subject based on the ideXlab platform.
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multiple time scale characteristics of rainfall and its impact on soil Salinization in the typical easily salinized area in huang huai hai plain china
Stochastic Environmental Research and Risk Assessment, 2012Co-Authors: Jingsong Yang, Guangming Liu, Rongjiang Yao, Xiangping WangAbstract:On the basis of monthly rainfall data over 50 years, we analyzed temporal properties of annual and seasonal rainfall variability by using and comparing two kinds of continuous wavelet transforms. Furthermore, we deduced its impacts on soil Salinization in the area of Huang-Huai-Hai Plain, China. Results showed that the annual rainfall collected by the studied area showed a decreasing trend during period 1960–2009 at a climatic tendency rate of 14.43 mm/10 years. The Morlet wavelet is better at capturing local feature of rainfall oscillatory behaviors at fine time scales, and the Mexican Hat wavelet is better at revealing global feature of rainfall period. Combining Wavelet transform with wavelet power spectrum and its confidence test, we found the 8-year dominant period of annual rainfall and the 5-, 6-, 10- and 12-year dominant periods of seasonal rainfall, respectively. The annual and seasonal rainfall trends in the near future and their impacts on soil Salinization are deduced based on the rainfall dominant periods and the prominent correlation between rainfall and soil salinity changes. The annual rainfall will still be in a relatively low period in the subsequent year after 2009 and then revert to a relatively high period during 2011–2014. The subsequent summer variability of rainfall may be helpful for reducing the soil Salinization, while the opposite trends of spring and autumn rainfall variability may aggravate the soil Salinization. This suggests sustainable irrigation and drainage measures to prevent soil Salinization in this area.
David Zimmermann - One of the best experts on this subject based on the ideXlab platform.
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assessing secondary soil Salinization risk based on the psr sustainability framework
Journal of Environmental Management, 2013Co-Authors: De Zhou, Zhulu Lin, Liming Liu, David ZimmermannAbstract:Risk assessment of secondary soil Salinization, which is caused in part by the way people manage the land, is an essential challenge to agricultural sustainability. The objective of our study was to develop a soil salinity risk assessment methodology by selecting a consistent set of risk factors based on the conceptual Pressure-State-Response (PSR) sustainability framework and incorporating the grey relational analysis and the Analytic Hierarchy Process methods. The proposed salinity risk assessment methodology was demonstrated through a case study of developing composite risk index maps for the Yinchuan Plain, a major irrigation agriculture district in northwest China. Fourteen risk factors were selected in terms of the three PSR criteria: pressure, state, and response. The results showed that the salinity risk in the Yinchuan Plain was strongly influenced by the subsoil and groundwater salinity, land use, distance to irrigation canals, and depth to groundwater. To maintain agricultural sustainability in the Yinchuan Plain, a suite of remedial and preventative actions were proposed to manage soil salinity risk in the regions that are affected by salinity at different levels and by different Salinization processes. The weight sensitivity analysis results also showed that the overall salinity risk of the Yinchuan Plain would increase or decrease as the weights for pressure or response risk factors increased, signifying the importance of human activities on secondary soil Salinization. Ideally, the proposed methodology will help us develop more consistent management tools for risk assessment and management and for control of secondary soil Salinization.
