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CONTENTS
Volume 41, Number 3, May10 2025
 


Abstract
Dolomite by-products, often considered waste spillages from mining sedimentary rock deposits, represent a significant environmental challenge due to their improper disposal. This study investigates the potential use of these by-products as sustainable geomaterials for road embankments. Laboratory tests conducted in accordance with ASTM standards evaluated the microfabric structure, particle size distribution, compaction behavior, load-bearing capacity, and permeability characteristics of dolomite by-products. Results classify the material as well-graded silty sand with low plasticity with USCS symbol of SWSM. It falls under the AASHTO group A-1-b, indicating an excellent to good general subgrade rating. Microstructural analysis reveals angular particles with sharp edges, promoting interlocking and strength, while chemical analysis indicates a composition dominated by oxygen and carbon with traces of magnesium and calcium. The material achieves a maximum dry unit weight of 18.31 kN/m at an optimum moisture content of 8.34%, with California Bearing Ratio (CBR) values ranging from 6% to 19%, rating it as a fair subbase material. Permeability tests show medium drainage characteristics with coefficients ranging from 0.0187 cm/sec to 0.0417 cm/sec suitable for subgrade applications with adequate drainage. Predictive models for hydraulic conductivity and load-bearing capacity provide practical tools for field applications. Comparative analysis highlights the material's performance as superior to clayey subgrades and comparable to sandy subgrades. This study establishes dolomite byproducts as a viable alternative geomaterial for road construction, addressing waste disposal issues while promoting sustainable construction practices. Limitations include the absence of shear strength and compressibility data, suggesting avenues for further research.

Key Words
compaction behavior; dolomite by-productpermeability; geomaterial; load-bearing capacity

Address
Mary Ann Q. Adajar, Jackielyn Mae F. Bacay, Andre Angelo L. Chu and Daryl Ann Del Rosario: Department of Civil Engineering, Gokongwei College of Engineering, De La Salle University, 2401 Taft Avenue, Manila 0922, Philippines

Abstract
POM pipes are used to transport fluids. For this application, in-depth knowledge of the material's mechanical behavior and long-term performance is essential when subjected to mechanical stress. This article used an experimental approach based on macroscopic tests (thermal analysis technique for POM, tensile testing on notched axisymmetric specimens with measurement of the volume change), and complementary microscopic observations (MEB) to identify the cause of the damage. The results of the tests carried out at ambient temperature will be presented to show the influence of the type of control and the measurement principle (an assumption of homogeneous or isochoric deformation versus an assumption of transverse isotropic deformation) on the materia's response.

Key Words
differential thermal analysis DTA; MEB; polyacetal; stress; thermogram DSC analysis; thermogravimetric

Address
S.A. Reffas and M. Elmeguenni: Department of Engineering Mechanics, University Djilali Liabes of sidi bel abbés, 22000, Algeria
M.S. Zagane and A. Moulgada: Department of Mechanical Engineering, University of Ibn Khaldoun Tiaret, 14000, Algeria
M. Yaylaci: Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey;
Turgut Kiran Maritime Faculty, Recep Tayyip Erdogan University, 53900, Rize, Turkey;
Murat Yaylaci-Luzeri R&D Engineering Company, 53100, Rize, Turkey
R. Yekhlef: Research center in Industrial Technology, CRTI, P.O.Box 64 Cheraga, 16014, Algiers, Algeria
Ş. Öztürk: Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey
M.E. Özdemir: Department of Civil Engineering, Cankiri Karatekin University, 18100, Çankiri, Turkey
E. Uzun Yaylaci: Faculty of Fisheries, Recep Tayyip Erdogan University, 53100, Rize, Turkey


Abstract
When a tunnel or underground cavern is excavated in a karst region, a hidden karst cave may occur close to the planned tunnel or underground cavern, which may potential to cause the collapse damage of the surrounding rock during the excavation. Since many previous studies on this issue are carried out based on a two-dimensional model, the three-dimensional collapse mechanism for the surrounding rock is not well investigated. In this study, a three-dimensional approach to determine the rock mass collapse range caused by a hidden spherical karst cave above a rectangular cavern is developed. Based on the rock mass collapse characteristics caused by a hidden karst cave above the deep cavern roof, a three-dimensional rock mass collapse mechanism is established, and the collapse surface equation is derived from the variational approach in combination with the upper bound theorem. By utilizing the aforementioned collapse surface equation, three-dimensional collapse surfaces influenced with varying parameters are depicted. Moreover, a numerical model that describes a spherical karst cave occurring above a rectangular cavern is established by employing three-dimensional numerical software, and the numerical solution of the collapse surface is obtained, which is represented by contour of maximum shear strain increment. By comparing the collapse surface derived from the latter computation and that attained from numerical simulation, the validity of the proposed approach is demonstrated.

Key Words
collapse volume; difference method; three-dimensional collapse surface; three-dimensional failure mechanism; variational approach

Address
Fu Huang, Min Zhang and Tonghua Ling: School of Civil and Environmental Engineering, Changsha University of Science and Technology, Changsha, Hunan, China
Xiaoli Yang: School of Civil Engineering, Central South University, Changsha, Hunan, China

Abstract
The swelling/shrinkage behavior of expansive soils in relation to water content may pose considerable threats to the infrastructures above them. While piles are commonly used to address this issue, the performance of pile-soil systems is usually elusive. In this context, the paper numerically studies the bearing behavior and uplift potential of a single pile in expansive soils. To this end, the stress-strain responses and shear strength variation of expansive soil specimens under different water contents are experimentally investigated through a series of consolidated undrained (CU) triaxial tests. Based on the dataset, threedimensional (3D) finite element analyses of a single pile in expansive soils are conducted using the thermo-mechanical module of ABAQUS. This approach utilizes the association between water-induced soil swelling/shrinkage behavior and that caused by temperature changes. The results reveal that as the water content within the effective depth increases, the ultimate bearing capacity of the pile initially rises and then declines, due to the competing mechanism between soil strength reduction induced by water infiltration and the upward soil-to-pile friction provided by soil swelling effects. Such a competing mechanism is shown to play a non-negligible role in affecting the interplay between the pile uplift potential and water content. In addition, the uplift potential is also influenced by the variation in pile self-weight due to the change of pile length or diameter.

Key Words
bearing behavior; expansive soils; finite element modeling; pile; soil swelling

Address
Xilin Lü, Yishun Zhong and Zheng Su: Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University,
Shanghai 200092, China
Dawei Xue: Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University,
Shanghai 200092, China
Huanhuan Du: College of Architecture and Energy engineering, Wenzhou University of Technology, Wenzhou, 325035, China

Abstract
This study comprises the design of rectangular underground water tanks under different ground conditions and the strength analysis of slab floor, walls, and foundation of rectangular underground water tanks. The importance and sustainability of water storage and management for humans is a very important and detailed issue. In this research, the design and analysis of rectangular water tanks to be constructed in ZA and ZE ground classes classified according to the Turkish earthquake regulation (TBDY 2018) were made using the IdeCAD program. The results of the stress, moment and deformation analyzes according to the design made with the design parameters used in this research showed that the rectangular water tanks to be built in the ZA ground class have structural strength against the stresses arising from soil, water and earthquake loads without suffering any significant deformation. The design values obtained using stress, deformation, and structure overturning moment analyses were found to be with in the limits of structural safety confirming the reliability of the design parameters. On the other hand, it has been found that underground water tanks to be built in the ZE soil class could also successfully resist to the lateral overburden and earthquake loads. However, it was determined that the deformations in the tank structure in ZE class soil were found higher than in the ZA class soil due to th e loose, weathered, and low bearing strength of the ZE class soils. This study also emphasizes the importance of using raft foundations under underground water tanks to be built on ZE class grounds to increase safety and prevent increasing deformations over time, such as creep.

Key Words
IDECAD; underground water tanks; ZA and ZE class soils and rectangular water tanks

Address
Pinar Sari Çavdar and Merve GÜÇ: Izmir Democracy University, Engineering Faculty, Department of Civil Engineering
Izmir Democracy University, Gursel Aksel Bulv. No: 14, İzmir, Turkey

Abstract
Recent years have witnessed a burgeoning interest in sustainable, eco-friendly, and cost-effective construction materials for civil engineering projects. Soilcrete, an innovative blend of soil and cement, has gained significant acclaim for its versatility and effectiveness. It serves not only as grout for soil stabilization in corrosive environments like landfills and coastal regions but also as a reliable material for constructing structural elements. Understanding the mechanical properties of soilcrete is crucial, yet traditional laboratory tests are prohibitively expensive, time-consuming, and often imprecise. Machine learning (ML) algorithms present a superior alternative, offering efficiency and accuracy. This research focuses on the application of the adaptive neuro-fuzzy inference system (ANFIS) algorithm to predict the uniaxial compressive strength (UCS) of soilcrete. A total of 300 soilcrete specimens, crafted from two types of soil (clay and limestone) and enhanced with metakaolin as a pozzolanic additive, were meticulously prepared and tested. The dataset was divided, with 80% used for training and 20% for testing the model. Eight parameters were identified as key determinants of soilcrete

Key Words
adaptive neuro-fuzzy inference system; compressive strength; laboratory test; soilcrete

Address
Ibrahim Albaijan: Department of Mechanical Engineering, College of Engineering at Al-Kharj, Prince Sattam Bin Abdulaziz University, Al Kharj 16273, Saudi Arabia
Abdelkader Mabrouk: Department of Civil Engineering, College of Engineering, Northern Border University, Arar 73222, Saudi Arabia
Wael S. Al-Rashed: Department of Civil Engineering, Faculty of Engineering, University of Tabuk, P.O. Box 741 Tabuk 71491, Kingdom of Saudi Arabia
Mehdi Hosseinzadeh: School of Computer Science, Duy Tan University, Da Nang, Vietnam;
Jadara Research Center, Jadara University, Irbid 21110, Jordan
Khaled Mohamed Elhadi: Department of Civil Engineering, College of Engineering, King Khalid University, Saudi Arabia;
Center for Engineering and Technology Innovations, King Khalid University, Abha 61421, Saudi Arabia


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