Stability Analysis of a High-Steep Dump Slope under Different Rainfall Conditions
Round 1
Reviewer 1 Report
The paper entitled " Stability analysis of high-steep dump slope under different rainfall conditions" is a very interesting study that investigates the slope stability with unsaturated soil using the finite element method. Xinxing Coal Mine of Wuhai has been chosen as case study.
The paper can be published after the following suggestions/comments.
1) In the introduction, check the reference Muhammad et al. [13]. Author's last name should be used.
2) In paragraph 3.1, it may be interesting to report the locations where the two samples were retrieved.
3) The reference list should report also the following references that have been cited in the manuscript:
- GB / T50123-2019
- HJ 651-2013
-GB50021-2001
4) Report more information about the location of Xinxing Coal Mine.
5) Minor spell check required;
6) About the importance of the finite element modelling, authors may consider also the following papers:
Castelli, F.; Grasso, S.; Lentini, V.; Sammito, M.S.V. Effects of Soil-Foundation-Interaction on the Seismic Response of a Cooling Tower by 3D-FEM Analysis. Geosciences 2021, 11, 200. https://doi.org/10.3390/geosciences11050200
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
In my opinion, this work merges two studies - Tu et al. (2016) and Tang et al. (2018). The big problem is that water interferes with soil particles depending on the clay or sand predominance. Tang et al. (2018) apply their theory to specific sandy soil, and call attention to this aspect. Because water behavior in sandy and clay soil is entirely different, it is essential to characterize the material - grain size distribution and its quantification, and characterize the type of clay, if it is a significant fraction to explain the swelling potential.
From literature - It has been reported that the sediment yield and runoff production of a slope, are significantly impacted by soil texture, slope topography, rainfall intensity and cover condition (Fox et al., 1997, Qing-quan et al., 2001, Rieke-Zapp and Nearing, 2005, Zhang et al., 2018).
From literature - Since the slopes are typically in an unsaturated state, part of the flow infiltrates the slope, which increases the pore water pressure and seepage forces within the slope. When the water table is close to the surface of the slope, the rise in pore water pressure diminishes the effective stress of the slope soil, reducing the soil strength and may trigger the slope failures (Harden and Scruggs, 2003, Muntohar and Liao, 2010).
From literature - Fine-grained soil slopes that are in a state of the unsaturated condition typically undergo a large deformation prior to reaching failure conditions (Ng, Zhan, Bao, Fredlund, & Gong, 2003; Widger & Fredlund, 1979). In such scenarios, the soil shear strength in the sliding zone will drop from the peak shear strength (PSS) to the residual shear strength (RSS) due to the large shear strain. The phenomenon is widely referred to in the literature as strain-softening behavior (Skempton, 1964).
Part II of the work needs an improvement of the text redaction.... see the File with comments.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
I have gone through carefully the content and would like to inform that the paper represents the scientific level. The authors analyzed the progress and problem of previous researches. The conclusions are resulted from research presented in the paper but the discussion could be completed. It should be based on studies recently done. What is more, the paper was not prepared according to MDPI standards. It must be definitely improved. The punctuation should be also improved.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The reviewer still considers important the classification of the soil, taking into account the grain size and the clay type (quality). Quantifying the deformation by summing the swelling and settling movements, without mentioning whether they are positive and/or negative (only the absolute values), can introduce many errors in the interpretation of the final results.
The authors should read more about the settlement and swelling of natural materials... Some references are below.
B.R. Phanikumar, Ravideep Singla,
Swell-consolidation characteristics of fibre-reinforced expansive soils,
Soils and Foundations,
Volume 56, Issue 1,
2016,
Pages 138-143,
ISSN 0038-0806,
https://doi.org/10.1016/j.sandf.2016.01.011.
(https://www.sciencedirect.com/science/article/pii/S0038080616000123)
Abstract: Many innovative foundation techniques have been devised to counteract the swell-shrink problems posed by expansive soils. Some of these techniques include physical alteration, sand cushioning, cohesive non-swelling soil (CNS) layers, belled piers, under-reamed piers, granular pile anchors and chemical stabilisation. Reinforcing expansive soils with randomly oriented geo-fibres is also an effective technique for controlling the volumetric changes in expansive soils. This paper presents the swell-consolidation characteristics of fibre-reinforced expansive soils. Nylon fibre was used to reinforce expansive soil specimens. One-dimensional swell-consolidation tests were conducted to study the swell-consolidation characteristics of fibre-reinforced clay specimens. The fibre content (fc) was varied at 0%, 0.05%, 0.10%, 0.15%, 0.20%, 0.25% and 0.30% by the dry weight of the soil. The length (l) of the fibres was varied at 15mm and 20mm. The swell potential and the vertical swelling pressure decreased up to fc=0.25% for both fibre lengths, but increased mildly when fc was increased to 0.30%. The swell potential and the vertical swelling pressure decreased with an increasing fibre length (l) for all the fibre contents (fc). The rate of heave for the samples was also found to be in accordance with the above observations. The secondary consolidation characteristics of the fibre-reinforced samples were also studied and compared with those of an unreinforced specimen. It was found that the secondary consolidation characteristics of the fibre-reinforced specimens improved compared to those of the unreinforced specimen.
Keywords: Expansive soils; Fibre-reinforcement; Swell potential; Vertical swelling pressure; Rate of heave; Secondary consolidation
Prediction of final settlements of buildings constructed on expansive soils
María-de-la-Luz Pérez-Rea, Tania Ayala-Ibarra, Víctor M. Castaño
International Journal of Engineering & Technology, 4 (3) (2015) 424-431
Abstract
Because the action of the swelling pressure, the settlements caused by the transmitted load from the structure on expansive soils, and the settlements calculated by classic theories of soils mechanics are different. This swelling pressure acts in opposite direction to the weight of the building. In this paper, the authors propose the use of a volumetric strain coefficient by settlements exp, in a soil-structure interaction algorithm taking into account the expansive soil behavior in the reduction of the settlement magnitude when a building is placed above soil. It’s necessary to know the initial properties of the expansive unsaturated soil and the load building conditions. A laboratory process is described for determining the aexp coefficient.
Keywords: Expansive Soils; Settlement; Soil Strain; Soil-Structure Interaction; Swelling Pressure.
https://www.bgs.ac.uk/geology-projects/shallow-geohazards/clay-shrink-swell/
https://events.saip.org.za/event/170/contributions/7705/attachments/2892/4146/ARTICLE%20INFLUENCE%20OF%20SWELLING%20ON%20THE%20SETTLEMENT%20OF%20CLAY%20SOILS%20OF%20VIRTUS%20TOHOUNGBA
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
I accept the improvements made to the work and consider it publishable.
However, I have some doubts regarding the fact that the authors consider settlements as a positive vertical deformation (+) and expansibility as a negative vertical deformation (-).
Please confirm the citations in the text and the respective references.
Author Response
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Author Response File: Author Response.pdf
