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Evaluating the slope behavior for geophysical flow prediction with advanced machine learning combinations
(2025-12-01)
Onyelowe, Kennedy C.
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Ebid, Ahmed M.
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Hanandeh, Shadi
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Kamchoom, Viroon
Ensuring safety in geotechnical engineering has consistently posed challenges due to the inherent variability of soil. In the case of slope stability problems, performing on-site tests is both costly and time-intensive due to the need for sophisticated equipment (to acquire and move) and logistics. Consequently, the analysis of simulation models based on soft computing proves to be a practical and invaluable alternative. In this research work, learning abilities of the Class Noise Two (CN2), Stochastic Gradient Descent (SGD), Group Method of Data Handling (GMDH) and artificial neural network (ANN) have been investigated in the prediction of the factor of safety (FOS) of slopes. This has been successfully done through literature search, data curation and data sorting. A total of three hundred and forty-nine (349) data entries on the FOS of slopes were collected from literature and sorted to remove odd values and unlogic results, which had been used together in a previous research work. After the sorting process, the remainder of the realistic data entries was 296. The previous work which had included unrealistic data entries had unit weight, γ (kN/m<sup>3</sup>), cohesion, C (kPa),angle of internal friction (Φ°), slope angle (°), slope height H (m), and pore water pressure ratio, r<inf>u</inf> as the studied parameters, which formed the independent variables. After careful checks, the initial results showed poor correlation with the individual factors and the factors were collected into three non-dimensional parameters based on the understanding of the physics of flows, which are: C/γ.h-Cohesion/unit weight x slope height, tan(ϕ)/tan(β)-the tangent of internal friction angle/Tangent of slope angle, and ρ/γ.h-Water pressure/unit weight x slope height, which are deployed as inputs and FOS-the safety factor of the slope as the output. At the end of the exercise, the ANN outclassed the other techniques with SSE of 62%, MAE of 0.27, MSE of 0.21, RMSE of 0.46, average total error of 24%, and R<sup>2</sup> of 0.946 thereby becoming the decisive intelligent model in this exercise. However, there is an advantage the deployment of GMDH, which comes second in order of superiority, has over the ANN. This is the development of a closed-form equation that allows its model to be applied manually in the design of slope stability problems. Overall, the present research models outperformed the eleven (11) models of the previous work due to sorting and elimination of unrealistic data entries deposited in the literature, the application of dimensionless combination of the studied slope stability parameters and the superiority of the selected machine learning techniques.
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Modelling root decomposition effects on root reinforcement and slope stability
(2025-03-01)
Phan, Trung Nghia
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Leung, Anthony Kwan
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Nguyen, Thanh Son
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Kamchoom, Viroon
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Likitlersuang, Suched
This study investigates the influences of root decomposition of two vetiver species on mechanical root shear reinforcement and vegetated slope stability. The transient variations of maximum root shear reinforcement (C<inf>r,max</inf>) of vetiver species was examined by combining the extended Root Bundle Model with the modified Wu's model. Existing laboratory data of the biomechanical properties (i.e., tensile strength, secant modulus) and morphological traits (i.e., diameter distribution, root length, orientation) of the decomposing roots following herbicide application were used as input parameters in the root reinforcement models to predict the root shear reinforcement. The predicted C<inf>r,max</inf> was then used in the slope stability analysis on the basis of Morgenstern-Price method to evaluate the temporal variation in the stability of vegetated slope with different slope angles and plant killing patterns. The combined model was capable of predicting the exponential reductions in C<inf>r,max</inf> following the transient declines in the root strength, secant modulus and diameter. The large variability in the tensile strength of decomposing roots could also be well captured through the use of Weibull survival function. The slope stability analysis highlighted that the vetiver roots contributed the most to the stability of slope when the slope angle was less than 45°. Additionally, it is recommended to refrain from killing the plants grown near the slope's toe, because this region is particularly susceptible to shallow slope failure.
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Hydromechanical behaviour of a slope reinforced by grass roots under rainfall conditions
(2024-12-01)
Prasetyaningtiyas, Gayuh Aji
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Kamchoom, Viroon
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Leung, Anthony Kwan
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Likitlersuang, Suched
Soil bioengineering using vegetation has been considered an environmentally friendly solution to improve slope stability. Although several studies have demonstrated the contribution of vegetation to slope stability, a gap in understanding the mechanisms of grass root–soil interactions under rainfall conditions remains. This study investigates the effects of the roots of vetiver grass (Chrysopogon zizanioides) on the hydromechanical behaviour of an unsaturated soil slope using the centrifuge modelling technique. The changes in pore water pressure and slope deformation were monitored during the test. The monitored data were subsequently back-analysed and interpreted using seepage–stability analyses. In addition, this study focused on evaluating the effect of roots on slope stability, considering safety and pore water pressure during rainfall. Results revealed that the vetiver roots remarkably affected the initial suction of the slope by increasing the soil's air-entry value. The increased suction and the additional cohesion provided by the roots enhanced slope stability under rainfall conditions.
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Effect of root growth on slope hydrology and stability during early plant establishment
(2020-01-01)
Kamchoom, Viroon
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Jotisankasa, A.
The roots developed during early plant establishment could affect soil hydraulic properties, including soil water retention curve (SWRC) and hydraulic conductivity function (HCF). It remains unclear whether the changes in SWRC and HCF due to root growth are significant to slope stabilisation. This study aims to investigate effect of root growth on slope hydrology and stability during early plant establishment. Finite-element seepage-stability models of 45-degree clayey sand slopes subjected to intense rainfall were developed, with due consideration of coupled hydro-mechanical reinforcement and root-induced changes soil hydraulic properties. The results suggested that root growth increase infiltration rate by almost twice and resulted in significant loss of retained suction. Considering changes of SWRC and HCF influenced by fine roots can reduce slope stability by up to 22%.
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Hydro-mechanical reinforcements of live poles to slope stability
(2018-12-01)
Kamchoom, Viroon
;
Leung, Anthony K.
Soil bioengineering using live poles is an environmentally friendly technique for shallow slope stabilisation. However, it remains unclear in this technique whether the hydrological effects of pole transpiration are significant to slope stabilisation, compared to mechanical reinforcement by structural poles and their fibrous roots. The aims of this study were to investigate the hydro-mechanical reinforcement effects of live poles and to evaluate their effectiveness for shallow slope stabilisation, giving due consideration to the different pole growth stages. Finite-element seepage-stability models were developed and validated against centrifuge model tests that investigated the rainfall-induced instability of a 45-degree clayey sand slope subjected to intense rainfall. The short-term stability right after the installation of the poles is critical because only structural poles, i.e., without fibrous root reinforcement or water uptake, are insufficient for reinforcement, even those as long as 2 m. Due to the absence of pole transpiration, positive pore water pressure of up to 10 kPa was built up near the slope toe, causing the significant mobilisation of shear strain and consequentially slope failure. In longer term, during which fibrous roots developed and provided additional mechanical reinforcement (via root cohesion) and transpiration-induced suction, no slope failure occurred due to the considerable amount of suction that was retained within the pole zone. It was mainly the pole transpiration before the rainfall, i.e., antecedent drying, that retained the suction, rather than the transpiration that took place during the rainfall.

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