Soil–water retention curves and microstructures of undisturbed and compacted Guilin lateritic clay

Abstract

To investigate the soil-water retention curves of undisturbed and compacted lateritic clay specimens in the full suction range, suction is imposed or measured by using the pressure plate method, filter paper and vapor equilibrium technique with a saturated salt solution. The mercury intrusion porosimetry (MIP) tests were also performed to observe the pore size distribution (PSD) of undisturbed and compacted samples. The test results show that the undisturbed samples have lower gravimetric water content and degree of saturation than the compacted samples at the same density in the suction ranging from 0 kPa to 10 MPa. According to the study on microstructures, the observed phenomenon can be explained by internal cracks of undisturbed samples continuing to develop along with an increase in suction. When the suction is higher than 10 MPa, the soil-water retention curves (SWRCs) coincide with each other for both undisturbed and compacted samples. Undisturbed samples exhibit a unimodal PSD, while unsaturated, compacted samples have a distinct bimodal PSD. The structural degradation of the clay aggregate due to the moisture change leads to the change of the interaggregate pores (the intra-aggregate pores remain almost unchanged). For unsaturated, compacted samples with different void ratios, the intra-aggregate PSDs are almost the same, while the inter-aggregate PSD varies with the void ratio. This can be adopted to explain that the wetting branches of the SWRCs are independent of the dry density in the high suction range when the SWRC is expressed by the relation between suction and gravimetric water content. The results of MIP tests on a saturated sample are used to predict the SWRC of the same soil in the main drying.

Evolution Characteristics of the Cracks in the Completely Disintegrated Carbonaceous Mudstone Subjected to Cyclic Wetting and Drying

“…To simulate the working condition of the embankment, the test samples were prepared at a degree of compaction of 96% and an initial water content of 14%. First, the grains were fully mixed with distilled water, sealed with a film bag, and then placed in a moisturizer box for 48 h. Afterward, the grains were weighed and then poured into the direct shear ring cutters with inner diameters of 61.8 mm and heights of 20 mm as used by Sun et al [27] and Zhang et al [28] among others.…”

A New Approach in Comparison and Evaluation of the Overall Accuracy of Six Soil-Water Retention Models Using Statistical Benchmarks and Fuzzy Method

“…Other researchers in this area include Amanabadi et al [3], Sun et al [50], Liu et al [32], Shahnazari et al [47], and Kuang and Jiao [28]. Review previous research that has been done thus far [5,24,43,45,49,51,52,55,56] showed that no research had been conducted to compare the accuracy of the models in all soil texture categories and simultaneously in two categories eld's data and laboratory data.…”

Volumetric behavior of natural swelling soil on drying-wetting paths. Application to the Boumagueur marl -Algeria-

“…The study of drying-wetting paths is a necessary step in the study of unsaturated soils behavior. Indeed, it has a double interest, on the one hand because it makes it possible to highlight the role of the suction to which the soil is subjected and to understand this important aspect of its behavior, on the other hand, many real phenomena follow, as a first approximation, drying-wetting paths (e.g., Al-Mahbashi et al, [2] Bendahgane et al, [5] Estabragh et al, [10] He et al, [15] Goual et al, [18] Seiphoori et al, [31] Sun et al, [33] Sun et al, [34] Tang et al, [35] and Wenjing et al [41] )…”