Origin of the high sensitivity of Chinese red clay soils to drought: Significance of the clay characteristics

D'Angelo, Benoît; Bruand, Ary; Qin, Jingxiu; Peng, Xinhua; Hartmann, Christian; Sun, Bо; Huang, Hao; Rozenbaum, Olivier; Muller, Fabrice

doi:10.1016/j.geoderma.2014.01.029

Cited by 27 publications

(8 citation statements)

References 33 publications

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“…[13] [14]. There are literatures on the relation between BSP and pH for red soil series in county scale [8] [9], but so far little information is available of red soils series in province scale.…”

Section: Introductionmentioning

confidence: 99%

Predicting Base Saturation Percentage by pH—A Case Study of Red Soil Series in South China

Wang¹,

Bing²,

Li³

2019

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pH and base saturation percentage (BSP) are two basic indexes in identifying soil types in Chinese Soil Taxonomy. Some studies proved that there is significant correlation between BSP and pH, thus it could save the cost of laboratory work if we can infer BSP directly from pH. In this study, the measured values of BSP and pH of 162 and 232 horizon samples from 48 and 55 red soil series surveyed from 2009 to 2011 in Fujian and Guangdong respectively were adopted from Soil Series Database to set up the optimal correlation model between BSP and pH. The results showed that: 1) BSP ranged from 2.30% to 94.02% with a mean of 25.07%, while pH from 3.42 to 6.91 with a mean of 4.98 for the total soil samples. 2) There were significant differences in pH between different soil types (R 2 were 0.624 for Ferralosols, 0.507 for Ferrosols, 0.515 for Argosols, and 0.456 for Cambosols, p < 0.01), in BSP between different parent materials (R 2 were 0.580 for Quaternary red clay, 0.434 for granite, 0.642 for sandstone, and 0.712 for basalt, p < 0.01), in pH and BSP between different land use types (R 2 were 0.623 for dryland, and 0.404 for forest land, p < 0.01). pH and BSP generally were in moderate variation (10%-100%), and in positive skew distribution (>0), their probability density curves were mainly in flat or normal curves (<0.67). 3) There is significant positive correlation between BSP and pH, and the optimal correlation models are in quadratic form in most circumstances, but the optimal model and the accuracy are different in different circumstances, changed with different regions, parent materials, soil types and land use types. The accuracy of models established in other studies when predicting our soil samples was lower compared with our models. pH < 5.33 or <5.93 could be used roughly to judge BSP < 35% or <50% based on the model of all red soil series (y = 6.84x 2 − 45.86x + 81.52, R 2 = 0.494, p < 0.01).

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Section: Introductionmentioning

confidence: 99%

Predicting Base Saturation Percentage by pH—A Case Study of Red Soil Series in South China

Wang¹,

Bing²,

Li³

2019

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“…Red clay is also widely distributed in Jiangxi Province and is a kind of special soil with the characteristics of high liquid limit and high water sensitivity [16][17][18]. After dry-wet cycles, it is easy to produce drying shrinkage cracks [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Improvement Effects of Completely Weathered Phyllite Using Red Clay and Cement for High-Speed Railway Embankments

Zhao¹,

Rao²,

Yang³

et al. 2022

Journal of Renewable Materials

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Completely weathered phyllite (CWP) has the characteristics of difficult compaction, low shear strength after compaction and large settlement after construction. The traditional improvement method using a single agent of red clay or cement for CWP satisfies the subgrade requirements for ordinary railway, but cannot meet the requirements of immediate strength and long-term post-construction settlement of high-speed railway at the same time. A series of experimental investigations were undertaken for the blended CWP soils, with three additives used. The first additive was red clay, the second was cement and the third was a combination of both red clay and cement at various portions. Results of consolidation test and shear strength test carried out for the treated CWP soils show that: 1) The effect of cement on improving the compression modulus of CWP is much better than that of red clay; 2) The settlement of an embankment of 10 m high formed by blended soil of CWP with 3% cement can be controlled within 15 mm, while the settlement will be 25.15 mm for the same embankment of blended soil of CWP with 40% red clay; 3) The shear strength and ultimate bearing capacity of CWP improved by red clay are much better than those of 5% cement; 4) The ultimate bearing capacity of CWP improved by 40% red clay is 3.42 times of that by 3% cement and 2.95 times by 5% cement. Furthermore, the bearing capacity of CWP when improved by red clay can meet railway subgrade requirements immediately after compaction, while cement improved CWP needs a curing time of 1 day or longer. This is an impediment to rapid construction process. The improvement mechanism of red clay is mainly filling effect and grading improvement effect, while the improvement mechanism of cement is mainly hardening reaction, which produces high strength material to cement. It is found that 40% red clay and 3% cement treated CWP, which is considered to be optimum, can meet the subgrade requirements of both immediate bearing capacity and long-term post-construction settlement for the high-speed railway.

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“…e high strength of red clay means that it is often mistaken as a good foundation soil. However, because of the high shrinkage of red clay, when its thickness variation in the horizontal direction is large, uneven settling can easily occur over time, leading to building damage [1]. To promote economic development, China has stepped up its efforts to construct infrastructure in its western region.…”

Section: Introductionmentioning

confidence: 99%

Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

Chen

Yang

et al. 2020

Advances in Materials Science and Engineering

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The influence of precipitated calcium carbonate on the strength and microstructure of red clay was studied. Precipitated calcium carbonate was added to red clay at ratios of 0%, 5%, 10%, 15%, and 20%. Shear tests were carried out on the samples to observe the effect of calcium carbonate on the mechanical properties of red clay. The results showed that, with increasing calcium carbonate content, the strength of red clay first decreased and then increased. The maximum strength was obtained for the sample with 20% calcium carbonate. Scanning electron microscopy (SEM) was used to observe the changes in microstructure caused by addition of calcium carbonate. The pores and cracks analysis system (PCAS) was used to quantitatively characterize the microstructure changes detected in SEM images. The addition of calcium carbonate decreased the pore area and increased the total number of pores of red clay. The incorporation of calcium carbonate caused the red clay particles to agglomerate. The higher the calcium carbonate content, the stronger the agglomeration of red clay particles in the soil samples.

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Origin of the high sensitivity of Chinese red clay soils to drought: Significance of the clay characteristics

Cited by 27 publications

References 33 publications

Predicting Base Saturation Percentage by pH—A Case Study of Red Soil Series in South China

Predicting Base Saturation Percentage by pH—A Case Study of Red Soil Series in South China

Experimental Study on Improvement Effects of Completely Weathered Phyllite Using Red Clay and Cement for High-Speed Railway Embankments

Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

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