Abstract
In engineering geological formations, it is common to encounter discontinuous grading soils. However,
existing grading equations have limitations in representing these discontinuous gradings, which are mainly
manifested in a single morphological limitation and quantitative expression. This study proposes a unified equation
for describing continuous and discontinuous grading of coarse-grained soil. The equation's basic properties were
investigated to check its ability to reflect different forms of grading curves. Additionally, the practicality of using this
equation for designing grading curves of coarse-grained soil was discussed. The main conclusions of this study are as
follows: By adjusting the grading segmentation parameter n in the grading equation, the equation can be made
applicable to both continuous and discontinuous grading curves. When n = 1, adjusting the grading curve anchor
point parameter gt,i, the anchor point control parameter dcr,i,, and the curve shape control parameter ki can achieve the
precise representation of three typical curves: hyperbolic, reversed S-shaped, and approximate straight line. When n =
2, inflection points may occur along a continuous grading curve, at which structural transitions in particle
composition and the dominant particle size take place. When n > 3, adjusting the parameters n,gt,i, dcr,i, and ki can
allow control over the number of inflection points and the particle content in different intervals of discontinuous
grading. The unified grading equation applies to both continuous and discontinuous grading curves of coarse-grained
soil in various regions. Its key parameters effectively link the granular skeleton state to macro-mechanical
performance, providing a predictive mathematical model for permeability, shear strength, and other engineering
properties, and offering a reference for assessing how grading continuity affects internal stability. The findings are
thus valuable for designing both continuous and gap-graded coarse-grained soils.
Address
Yiqian Xia: School of Civil Engineering, Central South University, Changsha, Hunan 410075, China
Jinyang F: School of Civil Engineering, Central South University, Changsha, Hunan 410075, China;
National Engineering Research Center of High-speed Railway Construction Technology, Changsha, Hunan 410075, China
Zhou Yang: Guangzhou Metro Construction Management Co., Ltd., Guangzhou, Guangdong 510330, China
Qianhui Sun: Power China Hubei Electric Engineering Co., Ltd., Wuhan, Hubei 430040, China
Jiawei Xie: School of Infrastructure Engineering, Nanchang University, Nanchang, Jiangxi 330031, China
Niu Zhang: National Engineering Research Center of High-speed Railway Construction Technology,
Changsha, Hunan 410075, China;
China Railway No. 10 Engineering Group Co., Ltd. Jinan, Shandong 250101, China
Abstract
To prevent contamination, the disposal of solid wastes in a landfill is a common practice in most
countries. According to the USEPA regulation, the liner of waste disposal landfills must have a hydraulic conductivity
of no more than 1x10-7 cm/sec. Fly ash, a by-product of thermal power plants, is generated in significant quantities;
approximately 13 million tons are produced annually by 11 thermal power plants in Turkey. This study aims to
evaluate the feasibility of using fly ash as a liner material. For this purpose, Type C fly ash was obtained from Afşin-
Elbistan power plant in Turkiye and modified by NaOH, xanthan gum, bentonite, borogypsum and glucose
monohydrate in laboratory. To investigate the properties of the modified material, hydraulic conductivity, unconfined
compression, contact angle, XRD, and SEM tests were performed. The results indicated that the engineering
properties of the modified fly ash changed significantly compared to the raw material. Based on these findings, fly
ash treated with NaOH, xanthan gum, and glucose monohydrate achieved lower hydraulic conductivity and can be
considered a suitable material for use as a waste disposal landfill liner.
Address
Uğur E. Yurtcan: Bingol University, Vocational School of Technical Science, 12000 Bingol, Turkiye;
Bingöl University Centre for Energy, Environment and Natural Disasters, Bingol, Turkiye
Hakan İkiz: Skyline Homes Inc. Erzurum, Türkiye
Lale Oncu: Erzurum Provincial Directorate of Environment and Urbanization, Erzurum, Turkiye
Seracettin Arasan: Evreka Engineering Comp., Erzurum, Türkiye
Lale Oncu: Erzurum Provincial Directorate of Environment and Urbanization, Erzurum, Turkiye
Abstract
Weathered sand normally has a lower shear strength and generally requires additional ground
improvement measures to fulfil the required bearing capacity. In situations where ground improvement measures are
considered inefficient or restricted due to site conditions, a skirted footing can be used as an effective measure to
increase bearing capacity. Additionally, the foundation can also be subjected to load eccentricity and load inclination
due to the moment and horizontal forces acting on the foundation, respectively. Under the combined effect of
moment and horizontal load, the footing is subjected to an eccentrically inclined loading condition, which in turn
reduces the ultimate bearing capacity. However, there is a lack of research work on the impact of combined (vertical,
horizontal and moment) load on a skirted square foundation. The present work provides laboratory test results on a
skirted square (B = 0.1 m) model footing in dense and medium-dense sand. The footing with skirt length varying
from L/B = 0 to 1 is subjected to a combined load eccentricity (e) and inclination (a). The load eccentricity varied
from e/B = 0 to 0.15, and load inclination varied from 0⁰ to 15. In addition to laboratory tests, finite element analysis
was conducted on a prototype footing (B = 1 m) to compare with the laboratory test results. The results indicate that
for any combination of e/B and a, the bearing capacity of a skirted footing improved with an increase in skirt length
ratio (L/B) compared to a spread footing (L/B = 0). The improvement is found to be 3.7 times in dense soil and 4
times in medium dense soil with L/B = 1 and for the loading at e = 0, a = 0. The improvement factor increases for the
case of e > 0, a > 0. A chart has been provided based on laboratory tests and finite element result to estimate the
ultimate bearing capacity of skirted footing under combined loading conditions.
Address
Atish K. Das: Department of Civil Engineering, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India
Chittaranjan Patra, Khaled Sobhan: Department of Civil, Environmental and Geomatics Engineering, Florida Atlantic University, Bldg. 36,777 glades Road, Boca Raton, FL 33431, USA
Abstract
The inclusion of geocell in weak soils has emerged as an effective option to enhance its performance.
The limitation of suitable land for construction and weaker foundation soils arise the need of interfering footings. The
present study investigates the response of circular and square interfering footings of equivalent area placed on
geocell-reinforced silty sand. A series of three-dimensional (3D) numerical simulations using finite element approach
(FEA) has been performed to evaluate the influence of parameters such as footing-spacing, geometry of geocellgeocell-
height and aperture-size, shear strength and stiffness of silty sand on the ultimate bearing capacity (UBC) of
interfering footings and the performance comparison thereof. The findings reveal that geocell reinforcement
significantly enhances the UBC by improving the confinement and load distribution with comparatively higher UBC
values for all the cases of circular interfering footings over the square ones. The UBC improvement for circular
interfering footings varies between 12.85-14.68% and 2.35-12.98%, depending on the spacing ratio and geocell
configuration respectively. More efficient stress distribution and mobilization of soil resistance for circular interfering
footings in addition to uneven stress concentrations at the corners for square footings, may lead to this discrepancy.
The study focuses on the importance of providing geocell reinforcement of variable geometry in improving the
performance of interfering footings placed on low-stiffness silty sand, with a comparative analysis of different footing
shapes. These outcomes provide practical implications for the design of interfering footings on geocell-reinforced
silty sand.
Address
Zuha Kanji: Department of Civil Engineering, National Institute of Technology, Hamirpur,
Himachal Pradesh - 177005, India
Shibayan Biswas: Department of Civil Engineering, Dr. B. R. Ambedkar National Institute of Technology,
Jalandhar, Punjab - 144008, India
Swaraj Chowdhury: Department of Civil Engineering, National Institute of Technology, Hamirpur,
Himachal Pradesh - 177005, India
Abstract
In this study, the strength variation of fiber-reinforced cement-added sand soils was examined. The
cement contents of the specimens were 2%, 4%, and 6% by the dry weight of the soil. The 6mm long fibers were
added at the ratios of 0%, 0.3%, 0.6%, and 0.9% by the dry weight of the soil. The specimens were cured for 7, 14,
and 28 days. It was seen that cement ratio and fiber ratio must be considered as separate components of the
specimens. 2% cement-added soil specimens with 0.9% fiber and 4% and 6% cement-added soil specimens with
0.6% fiber resulted in the highest compressive strength among their related specimen groups. The stress-strain
behavior, deformability index, secant modulus, tangent modulus, and energy absorption capacity of the specimens
were evaluated, and the failure modes of the specimens were visually inspected. Freeze-thaw experiments were
carried out with 0, 1, and 3 cycles. As the number of cycles increased, the strength of the specimens decreased, but
fiber reinforcement was successful to slow down the decrease in strength. The major outcome of this study showed
that fiber-reinforced cement-added sand soils could be a successful ground improvement choice even under the
effects of freeze-thaw cycles.
Key Words
cement; fiber; freeze-thaw cycles; sand; unconfined compressive strength
Address
Tugba Eskisar, Esma Rahat: Ege University, Faculty of Engineering, Department of Civil Engineering, 35100, Izmir, Turkey
Abstract
Various input parameters are required to estimate landslide susceptibility. However, it is difficult to obtain
all types of variables from each grid through experiments. The objective of this paper is to investigate the degree of
influence of the input parameters on the factor of safety based on a high-risk area (HRA) model to suggest the
number of minimum input parameters required to obtain a reliable factor of safety. Random forest (RF) and partial
dependence (PD) algorithms as well as Shapley additive explanations (SHAP) are selected to find the feature
contributions in the HRA. In total, 1800 data items for each input parameter are collected; these are used as input data
for the RF, PD, and SHAP algorithms. The influencing order of the independent data slightly differed, depending on
the algorithm used. The input variables ranked first to fourth present a similarity. The variables ranked as important
are individually applied as input data to create a deep neural network, and the predicted factor of safety is compared
with the true value. An oversampling algorithm is also used to investigate the effect of the number of data on
determining the influencing degree in each variable. The results demonstrate that this method could be applied to
discover key parameters if obtaining all types of input variable is difficult.
Key Words
feature; landslide susceptibility; oversampling; partial dependence (PD); random forest (RF);
shapley additive explanations (SHAP)
Address
Junghee Park: Department of Civil and Environmental Engineering, Incheon National University,
Incheon 22012, Republic of Korea
Hyung-Koo Yoon: Department of Construction and Disaster Prevention Engineering, Daejeon University,
Daejeon 34520, Republic of Korea
