Introduction. The convergence of the results obtained during the comparison of analytical and numerical methods using FEM in the Midas GTS NX PC for the calculation of cross-beam foundation and sloping foundation in case of sudden formation of karst-rockfall processes was analyzed. The analytical calculation method was developed on the basis of empirical data obtained during laboratory model tests in a special facility that allows modelling karst-rockfall processes, the numerical model was an identical prototype repeating qualitative and quantitative characteristics used in physical modelling.

Materials and methods. A comparative assessment of the convergence of the results obtained by two independent methods in the calculation of a cross-beam foundation on a sloping base in the conditions of karst-rockfall processes is given.

Results. The obtained discrepancies of the main quantitative parameters such as normal contact stresses under the bottom of the longitudinal strip of the cross-beam foundation, deformations of the foundation after the karst cavity emergence to the surface and formation of sinkholes were evaluated.

Conclusions. The reliability of the proposed numerical model was confirmed as a result of the research. It allows to reduce the labour intensity of laboratory tests and to expand the boundaries of research in further study of cross-beam foundation and sloping foundation performance in the conditions of karst territories.

Introduction. A programme of experimental research based on numerical modelling of pile group behaviour in a homogeneous sandy foundation is considered. The relevance of this work is due to the need to improve the reliability and safety of pile foundations, which are widely used in modern construction. The research is aimed at eliminating the existing gaps in predicting the interaction between piles and homogeneous soil. Within the scope of this study, a comprehensive experimental programme was developed and tested, including both modelling and field tests. The results obtained allowed us to propose new approaches to the calculation of pile groups, which has significant scientific and practical value for the construction industry.

Materials and methods. Data from scientific publications, regulatory documents, project materials, and experimental results were used. Methods of systematic analysis, modelling, as well as experimental and statistical approaches, were applied. These methods enabled the acquisition of new data and adjustments to the calculation methods for pile foundations.

Results. A numerical model for experimental research was developed, various calculation methods for pile foundations were analyzed, a test stand model was created, and a step-by-step experimental programme was designed.

Conclusions. The research results on the behaviour of pile groups in a homogeneous foundation have high scientific and practical value. The developed mathematical model and experimental data allowed to describe more accurately the distribution of loads and deformations in the pile group, which is a significant contribution to the theory of calculation of pile foundations. The obtained results confirm the necessity and importance of revising the existing methods of pile foundations calculation. Their introduction into construction practice and educational programmes will improve the reliability and efficiency of construction, as well as create a basis for further research in this field.

Introduction. A method for determining the lateral pressure on the excavation enclosure is proposed, which is based on the analysis of the stress state of the retained soil mass. It can be used both for non-cohesive and cohesive soils, for homogeneous or non-homogeneous structure of the retained mass, both with and without loads on its surface.

Materials and methods. Materials published by Russian and foreign scientists were used for comparative calculations, where the results of analyses, experiments and theoretical studies are given. All calculations are performed in the shell of the computer programme “Stability”, in which the determination of stress fields is carried out by the finite element method in a linear formulation.

Results. It was found that all the calculated values of lateral pressure with a sufficient degree of accuracy (for experimental studies) coincide with the corresponding values given in the cited works. The lateral pressure values obtained by the authors of the presented paper turned out to be 25–40 % less than the similar results given by the cited authors. The forms of the lateral pressure plots constructed by the authors of each of the cited works are congruent to the lateral pressure plots based on the proposals made in the paper. The difference between the numerical values of the lateral pressure obtained by the authors of the cited works and the values obtained by us is explained by the difference in approaches to the construction of the sliding
surface: in our case, the hypothesis of its flat shape is not used, but its construction is based on the analysis of stress fields taking into account the physical and mechanical properties of the soil.

Conclusions. Taking into account the satisfactory convergence of the compared results, we consider it possible to conclude that the announced method can be used in engineering calculations.

Introduction. Due to the increasing use of underground space in cities, deeper excavations are increasingly being used. These excavations contain more elements and increase the chance of failure of one of the elements. When excavations collapse, there is economic damage and possible loss of life. The current level of research regarding the protection of excavations from progressive collapse and the accidents that have occurred are reviewed. The purpose of the study is to evaluate the influence of modelling of concreting joints between trench wall sections on the redistribution of forces in case of an accidental impact in the form of failure of one strut.

Materials and methods. Numerical finite element modelling of a 16 m deep excavation constructed under the protection of a wall in the ground with a spacer system was carried out. The joints were modelled by interface elements taking into account their deformability and strength.

Results. The modelling of the concreting joints results in a redistribution of the forces in the struts within the same wall section. In the case of normal load combinations, the forces in the struts do not change on average depending on the joint modelling, but in the case of accidental impact, the forces in the design case with concreting joints increase. In the case of progressive collapse within the wall, the direction of action of the bending moments changes. The displacements of the ground surface in the case of joint modelling are smaller than in the traditional modelling method.

Conclusions. The results obtained will allow more accurate modelling of excavation enclosures, making their use more predictable and safer. As further research, more advanced models of concrete contact behaviour are envisaged. The use of identical reinforcement meshes on opposite faces of the wall in the ground is also recommended as a structural measure to prevent progressive collapse.

Introduction. Almost a quarter of the Earth’s landmass and two thirds of the territory of the Russian Federation, including significant areas with a high concentration of natural resources and minerals, are located in the permafrost zone. These soils have structural instability: temperature fluctuations lead to a radical decrease in their strength characteristics and the development of significant deformations, which can critically affect the safety and reliability of buildings and structures. The geographical features of the Russian Federation necessitate the development and refinement of computational methods for determining temperature fields in the bases of cryolithozone soils. This paper discusses the implementation of the problem of freezing and thawing of a soil mass using numerical methods.

Materials and methods. The main provisions of a nonlinear mathematical model describing temperature transformations in a soil body, taking into account the phase transition of a pore liquid into ice and the corresponding thermophysical processes, are presented. The model was implemented in a specialized software package developed by the authors that implements the finite element method.

Results. As part of the study, numerical calculations of the temperature effects of buildings and structures under construction on the soil mass in a flat substitution were carried out. Numerical models were considered taking into account the impact of boundary conditions of various types on the computational domain. The results of numerical calculations were compared in detail with the results of similar calculations performed in proven software packages.

Conclusions. In this paper, the main mechanisms of a numerical model describing temperature transformations in a soil body are formulated and their implementation using the finite element method is proposed. Additionally, recommendations are presented on the further development of the numerical model, including the solution of the deformation problem of determining the precipitation of thawing of a soil body.

Introduction. The study is devoted to the issues of modelling and calculating the process of excavation in the conditions of the city of St. Petersburg, where weak clay soils of various genesis are widespread. The relevance of the topic under consideration is due to the need to improve the accuracy and reliability of calculations of soil foundations in conditions of dense urban development. It is especially important to take into account the specific properties of weak clay soils, such as their undrained behaviour and, mainly, shear deformation. The paper focuses on the mechanism of shear hardening, which is critically important for predicting plastic deformations of clay soils in the pre-limit loading stage.

Materials and methods. The main provisions of the nonlinear mathematical model previously proposed by the authors describing the behaviour of weak clay deposits based on the shear hardening mechanism are presented. The untrained behaviour is described on the basis of the modified theory of instantaneous strength by Yu.K. Solovyov, taking into account the formation of excessive pore pressures under deviatory loading in a plane stress-strain state. The model was numerically implemented in a specialized software package developed by the authors that implements the finite element method based on the displacement method.

Results. As part of the study, a numerical calculation was carried out for the development of a pit protected by a cantilever tongue-and-groove fence in conditions of dense urban development in the Central District of St. Petersburg. The paper also provides a detailed comparison of the results of numerical calculations with data from geotechnical monitoring, including measurements of deformations of the tongue-and-groove fencing of the excavation and foundations of the surrounding buildings.

Conclusions. Based on this study, conclusions are drawn about the predictive capabilities of models with a shear hardening mechanism for pit calculations in conditions of weak clay soils. Recommendations are given on the further development of the proposed model, including improvements in taking into account the effect of unloading the base and changes in stiffness parameters during deformation.

Introduction. In conditions when the thickness of the mined seam does not allow to form the required cross-sectional excavation without cutting of the host rocks, it is advisable to apply technological schemes with reuse of preparatory workings. Research in the field of development of effective ways to assess the stability of reused preparatory workings in such conditions of bedding of seams at present remains relevant, including for the mines of the Pechersk Coal Basin. The task of the described research is to obtain a picture of changes in the stress-strain state of the geotechnical system under consideration and to estimate the displacement values of the near-contour areas of the preparatory mine workings at different positions of the face.

Materials and methods. Were used to carry out numerical experiments using the finite element method in the Midas GTS NX software package for the conditions of one of the operating mines in the Pechersk coal basin. The Coulomb – Mohr criterion was used to describe changes in the geomechanical state of the mining system. To assess the reliability of simulation results, comparisons were made with instrumental measurements of geometric parameters along the length of workings.

Results. During the simulation, the spatial distributions of the resulting deformations in the geomechanical system under consideration were obtained. The estimation of the magnitude of displacements in adjacent areas of preparatory mine workings was made as the face moved. The calculated values of vertical and horizontal displacements allow us to assess compliance with the requirements for fastening and protecting workings, as well as design specifications for the mining area. These values can be used to evaluate the effectiveness of decision-making. The results of model calculations are supported by data from mine instrumental observations.

Conclusions. The results of the study demonstrate that the proposed geomechanical model of rock mass fully reflects the main features of its structure and changes in the contours of preparatory mining operations during its operation and can be used to assess the effectiveness of various methods for maintaining it during reuse.

Introduction. Friction forces have a significant impact on results of the long-time compression tests of peat and peaty soils. Forces occur at the contact between the lateral surface of the sample and the metal ring during compression tests. The authors have developed an oedometer that allows to increase the reliability of laboratory test results by determining the compressibility characteristics taking friction impact into account.

Materials and methods. The oedometer was made by plastic additive manufacturing except for bronze ring. The diameter of the sample is 8.6 cm and the initial height of the sample is 3 or 5 cm. After stabilization of deformations void in the base of the odometer is released and a monotonically increasing load was applied to the upper part of the sample until the “breakdown” at the contact between the lateral surface of the peat sample and the ring. At the same time loosening of the sample was prevented by keeping samples with bolts. The studied peat had the following properties: density 0.98–1.02 g/cm3, water content 861–930 %, void ratio 11.8–14.2, decomposition degree 40–45 %. The tests were carried out at vertical stresses equal to 50 and 100 kPa respectively.

Results. Tests showed that up to 15–20 % of the load applied to the sample is required to overcome friction forces. This phenomenon should be taken into account in determining compressibility characteristics by adjusting the current load on the sample.

Conclusions. The advantage of the oedometer is the determination of compressibility characteristics including compression index taking into account the measurement error occurring from the friction forces at the contact of the sample with the ring. The manufacture of geotechnical devices by 3D printing is non-cost and time-consuming. This also makes it easier to modify the design during testing and simplifies the manufacture of spare parts.

Introduction. The performance of static soil tests with piles is a prerequisite for the design of pile foundations. The existing stands have a number of disadvantages, the main of which are the use of massive large-sized elements for creation of a load platform and performance of installation operations with the involvement of heavy lifting equipment. A number of disadvantages leads to a significant increase in the cost and duration of testing. To exclude these disadvantages, it is proposed to develop a new type of test bench in the form of a geodome. Prefabricated and demountable construction on bolted joints, working mainly on tensile forces will be a distinctive feature of the geodome.

Materials and methods. The comparative analysis of domestic and foreign stands including the results of patent search is carried out. The geometric calculation was performed according to the results of icosahedral approximation of the hemisphere using Autodesk Inventor. Static calculation was performed using the finite element method in STARK ES 2023.

Results. A new design of a stand in the form of a geodome for soils static tests with piles loaded up to 1,500 kN is developed. The performance of the geodome for soils tests by piles with loading up to 1,500 kN was proved according to the results of practice industrial testing. Its main advantages were identified: lightness — with an empty weight of no more than 15 kN, the geodome can be used to perform tests with loading up to 1,500 kN; speed — to reduce the time required to complete the work, several geodome designs can be used for testing. The anchors were tested for pull-out loads to determine their load-bearing capacity.

Conclusions. The use of geodome will allow to perform tests with maximum efficiency by reducing up to 75 % of additional financial costs, including due to a significant reduction of transport costs and exclusion of installation operations for the creation of the load platform, as well as reducing the total time of tests at the site due to their parallel organization.

Introduction. When designing foundation bases, questions arise about the deformation characteristics of soil under complex stress conditions. In this case, the issue of qualitative modelling in laboratory conditions of the calculated stress-strain state of the massif remains the most relevant. One of the solutions may be to study the mechanical properties of soils under block triaxial loading with independently adjustable vertical σ1 and horizontal σ2 = σ3 stresses.

Materials and methods. Laboratory triaxial block regime tests of clayey soils with disturbed structure were carried out. Modes with alternat.ing increasing and decreasing blocks of deviatoric loading were used, with the maximum value of the deviator of the first increasing block of loading and the amplitude of unloading for all modes were assumed to be the same. The studies were carried out on cubic-shaped specimens. A device with rigid edges was used.

Results. The main results of the conducted research are new data on the change in deformations and strength of specimens under block triaxial mode loading conditions depending on the magnitude of all-round compression. The analysis of the obtained results is performed. Some patterns of clayey soil behaviour are established. The mechanism of processes occurring in the specimen is substantiated.

Conclusions. The influence of the magnitude of lateral pressure on the development of linear and volumetric deformations of the specimen, the ultimate values of the destructive load, taking into account the presence of blocks of repeated deviatoric loading, was established.

Introduction. The densification of urban development necessitates the construction of buildings with a developed underground volume. At the same time, the foundations of existing buildings are located on the edge of the deep excavation. The task of assessing the impact of the construction of deep foundations on the surrounding buildings is important and relevant. The analysis of data on foundation settlements near the sides of deep excavations was carried out based on the results of numerical modelling and geotechnical monitoring in the studies of Russian and foreign authors.

Materials and methods. To assess additional settlements of building foundations near deep excavations, research of the stress-strain state of the foundation near a deep excavation was carried out using a model created in laboratory in a flat tray with transparent walls. The displacement values were recorded using video recording and electronic sensors, then processed.

Results. The results of the experiment are consistent with the results of other authors. A law was established for the distribution of horizontal stresses and displacements in the soil mass outside the deep excavation model. Based on the identified patterns, a method was proposed for calculating the settlement of foundations near deep excavations, taking into account changes in the stress-strain state in the surrounding soil.

Conclusions. Based on the results of the study, a pattern of uneven changes in the stress-strain state of soils at the base of building foundations on the edge of excavations was established. The deformation of the soil mass at the base of the foundations of buildings located in the collapse prism occurs nonlinearly and unevenly. The construction of deep excavations leads to a change in the stress-strain state of the soil mass of the base of the foundations located on the edge of the excavation. This leads to a change in the ratio of vertical and horizontal stresses, which causes a change in the deformation characteristics of the soil, resulting in an increase in settlement.

Introduction. This is the first investigation of the behaviour of precast concrete joint piles utilized in challenging soil conditions on a construction site in Kazakhstan.

Materials and methods. The following techniques were applied: evaluation of the bearing capacity of SCLT using field test data interpretation techniques and the ASTM’s dynamic DLT method for driving precast concrete joint piles.

Results. Only 7 % separated the dynamic DLT-PDA approach from the static approach. This implies that, in comparison to other current methods, the alternative dynamic DLT-PDA method is highly precise and effective. Dynamic tests were conducted by PDA (Pile Dynamic Analyzer) and static tests by the requirements of the American Society for Testing Materials (ASTM).

Conclusions. According to the test results have been made design changes in the pile foundation. Static tests (SLT) were carried out on 16-meter piles and precast concrete joint piles with a total length of 25.5 and 27.5 m cross-section 40 × 40 cm. SCLT is a highly accurate and robust system that enables you to monitor static pile tests whilst also ensuring the safety of site operatives. Featuring a cable, users are able to monitor safely and accurately from distance, eliminating the need for personnel to enter potentially dangerous testing zones. This study examined joint piles with a 400 × 400 mm cross section and a pin-joined connection, as well as their relationship with the soil of Western Kazakhstan will be analyzed.

Introduction. The effects of low-rise building mat on liquefiable site were investigated in this study.

Materials and methods. One-dimensional ground response analyses of a layered sand model profile were conducted using Midas. The UBCS and soil model was used.

Results. The excess pore water pressure and the stress/strain time histories as well as the ground deformation of the numerical model were examined.

Conclusions. With the comparison of the free-field solutions, if the liquefaction occurred, the mat can cause the subsoils to settle more and push the side soils to move laterally, which will yield sway motions of the mat. The deeper embedment of the mat sometimes would help to minimize such phenomenon.

Introduction. Designing and constructing highways in difficult soil conditions is a significant engineering objective that requires a comprehensive approach. Traditional design and construction methods may not be effective in unstable or heterogeneous soils, such as subsidence soils. This article discusses key aspects of highway design in complex soil conditions, including geotechnical analysis methods, material selection and application, and soil reinforcement techniques.

Materials and methods. Plate load tests and static pile tests of soils have provided a detailed assessment of soils’ mechanical characteristics and bearing capacity in the project area. These tests provide accurate data on the resistance coefficient and deformation properties, facilitating the adjustment of design solutions and selecting optimal strengthening and stabilization methods.

Results. The test results showed that the soil-bearing capacity of the pile is sufficient to support the maximum indentation design load. The authors also discuss a modern stabilization method, such as the use of geosynthetics, which was applied in the study and improves the bearing capacity and durability of the roadway.

Conclusions. An analysis of successful case studies of projects in difficult soil conditions highlights effective strategies and methods that can be adapted for different geological conditions. The results of the study emphasize the importance of a multidisciplinary approach and the application of modern technologies to ensure the stability and reliability of roadways in difficult soil conditions.

Introduction. Light railway transport (LRT) is the name of the public transportation system that Astana is currently building. The LRT project on Astana’s difficult soils is discussed in the article. Due to problematic foundation soils, both of these larger projects employed piled foundations.

Materials and methods. The bridge’s foundation was built using bored piles that ranged in length from 8 to 55 m and had a cross-section diameter of 1.0 to 1.5 m. Every bored pile has a design bearing capacity ranging from 4,500 to 9,500 kN.

Results. The integrity test (ASTM D6760–08) and static load test (GOST 5686–94) findings for bored piles are presented in this study. Under those circumstances, maintaining the integrity of each bored pile’s concrete body is crucial. Use the cross-hole sonic logging method to verify integrity. At the moment, the most trustworthy approach available for evaluating the integrity of a dug deep pile foundation on a building site is cross-hole acoustic logging, a non-destructive testing technique. After installation, integrity examinations are frequently the most practical way to evaluate the condition of the shaft.

Conclusions. The real site provided the results that were interpreted. Lastly, a few suggestions for testing procedures appropriate for Kazakhstan’s challenging ground conditions are made.

Introduction. The increasing demand for green and intelligent civil infrastructures necessitates high-precision Internet of Things (IoT) monitoring systems. Given the high sensitivity of geotechnical engineering to soil strains, it is essential to develop precise measurement approaches that can accurately capture soil strains ranging from micro-strain to large strains. In recent years, advancements in fibre optic sensing technology have enabled accurate measurements within geotechnical engineering. However, there is still a need to enhance measurement approaches for fibre optic sensing technologies across various strain levels. This study investigates several fibre optic sensing technologies, including point-distributed, array sensing, and distributed fibre optic sensors, and provides a comprehensive review of recent advancements in fibre optic sensing for the field of geotechnical engineering.

Materials and methods. Innovative methods and devices for high-precision small-strain fibre optic sensing are detailed. Additionally, a novel integrated fibre optic sensor device capable of measuring water pressure and total soil pressure using a signal transducer is introduced.

Results. The study also explores the use of 3D printing technology in fabricating these transducers. A fibre optic sensing method for monitoring cracks is presented, encompassing physical fabrication, calibration tests, and field engineering application verification.

Conclusions. The fibre optic sensing methods proposed in this study offer effective solutions for accurate measurement in geotechnical engineering across different environmental and disaster conditions.

Introduction. The Indian subcontinent is renowned for its numerous structural heritage wonders, which reflect the region’s rich cultural history. To preserve the historical significance of these marvels, systematic documentation through digitization is essential. Utilizing advanced techniques like photogrammetry and 3D modeling, surpassing traditional methods, ensures precise and accurate data capture, processing, and representation of heritage information. Combining digital documentation with seismic surface wave techniques to characterize subsoil seismic velocities is vital for sustainable heritage conservation, particularly against natural hazards such as earthquakes. This study focuses on the digital documentation of the Post Master General (PMG) Office in Trivandrum, an iconic structure celebrated for its cultural and architectural significance.

Materials and methods. Close-range photogrammetry was employed to capture and analyze images and Multichannel Analysis of Surface Waves (MASW) tests were conducted at the PMG office site to estimate soil shear wave velocities.

Results. From the photogrammetric images, 3D models, 3D rendered walkthroughs, and 2D line drawings were created resulting in the as-built documentation of the built heritage. These outputs serve as digital records, enhancing visual perception and aiding in the extraction of semantic information for heritage conservation and management. Additionally, the study attempts to characterize subsoil properties by developing a shear wave velocity (Vs) profile from the MASW test results which is crucial for seismic response analysis. The paper also suggests optimal parameters for data collection to effectively characterize the study area.

Conclusions. Thus, this paper presents a comprehensive approach for documenting the built heritage along with assessing and managing their seismic risk combining advanced digital documentation techniques with surface wave methods.

Introduction. Deep foundations are widely used as common foundations for construction work in Indonesia. The axial compression capacity of deep foundations or simply we called it pile, consist of friction and end-bearing.

Materials and methods. Many formulas used to predict the capacity, and yet the behavior better achieved from instrumented static compression test pile.

Results. This paper shown a load transfer behavior for bored pile with diameter of 120-cm with effective length of 30-m constructed in very soft to stiff clay soil with its toe seated in very dense sand.

Conclusions. Result showed that long piles capacity in soft to medium clay dominantly resist by its friction under small displacement (<0.7 % diameter), while the end-bearing fully mobilized under higher displacement (>10 % diameter).

Introduction. As energy piles are increasingly utilized for sustainable energy solutions, understanding how thermal loading affects stress distribution within pile groups becomes essential for optimizing their design and functionality. The research aims to elucidate the mechanisms of stress transfer and the resultant effects on pile group behaviour.

Materials and methods. A 1g physical modelling approach was used to investigate the thermo-mechanical behaviour of 2 × 2 pile groups under asymmetrical thermal loading. Three separate tests were conducted, each featuring a group with 1, 2, or 3 energy piles subjected to cyclic thermal variations. The model employed closed-end aluminum pipes for the piles and dry, fine-grained silty sand for the ground. During thermal cycling, pile-head displacements, axial forces and bending moments along the piles, soil pressure changes beneath the pile tip, and temperature distribution around the group are monitored.

Results. The study demonstrates that thermal cycling has a substantial impact on load distribution among energy piles, with load shares rising during heating phases and falling during cooling phases. This results in an irreversible increase in load share due to soil compaction beneath the pile tips. Additionally, the contribution of the pile tip to the estimated head load increases with each heating-cooling cycle, underscoring the effects of thermal softening at the soil-pile interface.

Conclusions. Experimental observations suggest that the classic Boussinesq method may underestimate soil pressure beneath the pile tip during heating phases, potentially due to the soil’s plastic behaviour.

Introduction. Gypseous soil is one of the problematic soils that have substantial strength while dry but lose strength especially in wetting or saturation condition due to the significant reduction of its strength parameter and bearing capacity upon loading where gypseous cementing bonds have been dissolute and collapsed in the wet condition (Soil collapse occurs when increasing moisture weakens chemical or physical connections between soil particles), and therefore resulting in excessive settlements affects the stability of the engineering structures. Gypseous soils occupy about 1.865 million km2 in the world; the percent of gypseous in Iraq is 6.7 % of the total world gypsiferous area and about 28.6 % of the total area of this country.

Materials and methods. Stone column is a soil improvement technique used for stabilization and reinforcing of soft soil (low strength soil) by increasing of bearing capacity (increasing strength) and reducing the settlement and control it (consolidation acceleration).

Results. The aim of this study is to investigate the performance of gypsum soil reinforced by stone columns, where laboratory loading tests were performed on unreinforced and reinforced gypsum soil using big steel box as modeling and stone columns was have different diameters (5, 10, 15 and 20 cm) and fixed depth (30 cm).

Conclusions. The results showed that the settlement decrease with increase the stone column diameter and the bearing capacity increase when diameter increase.

Introduction. A soil-cement composite, comprising a thoroughly blended mix of soil, cement, and water, has played a crucial role in the construction of various civil infrastructures like bridge foundations, tunnels, highway embankments, foundations for port and harbour structures, and many more. Though efficient, traditional high-cement formulations pose severe environmental concerns, leading to the exploration of alternative materials that can bring sustainability to construction practices.

Materials and methods. This study focuses on utilizing “Ground-Granulated Blast-Furnace Slag” (GGBS) to explore its impact on the engineering characteristics of soil-cement mixtures. In this investigation, clay soil is blended with 20 % of OPC and varying proportions of GGBS (20, 25 and 30 % by weight of cement) as a replacement for OPC.

Results. The composite mixture is subjected to several Unconfined Compressive Strength (UCS) tests to assess the undrained shear strength of soil-cement-GGBS mixtures at distinct curing intervals (7, 14, and 28 days). Field emission scanning electron microscopy (FE-SEM) is also employed to examine the microstructure of the soil-cement composite, revealing the arrangement of particles, pore structures, and the distribution of cementitious materials.

Conclusions. The results show that the composition having clay soil and 20 % cement, replaced with 20 % GGBS, yields maximum strength among all tested compositions with a significant increase of 24 % compared to the conventional soil-cement mixture of clay soil and 20 % cement only.

Introduction. Geotechnical engineering creates a positive environment for innovation due to its multidisciplinary nature and the fact that people have been involved with the soil in every aspect since the establishment of the first civilizations. For invention and innovation, there is a need for ideas that are free from stereotypes, unafraid of making mistakes, inquisitive, productive, diverse and creative. Anatolian civilizations proved their creativity and innovation thousands of years ago with great geotechnical engineering structures.

Materials and methods. Six innovative applications developed at Bogazici University: improvement of pile shaft capacity with lime slurry; rubber added compacted clay liner for underground petroleum tanks; geomaterial production by cold bonding pelletization; compaction of fly ash by using ice; large size large displacement multiple purpose direct shear test apparatus; multiple friction joint pile with adjustable stiffness are presented in this paper. The main objective of the developed methods is to offer environmentaly safe, affordable, sustainable and resillient geotechnical engineering solutions that are accessible to every country in the world and can be easily implemented locally.

Results. The developed methods are practical and have technical advantages over the existing more complicated methods and do not need specialized high cost construction eqipment. Innovative methods can create added value in geotechnical engineering that is compatible with nature, easily accessible and sustainable.

Conclusions. In order to develop creative ideas, during academic education, especially at the doctoral level, instead of stereotyped ideas, ready-made package software and implementation theses, creative projects with strong scientific aspects should be emphasized where new ideas are produced and innovation is encouraged.

Introduction. Designing for geotechnical stability in tropical zones presents a unique set of challenges due to the climatic, geological, and environmental factors prevalent in these regions. It requires a comprehensive understanding of the local soil conditions, climatic factors, and environmental challenges. Materials and methods. Tropical regions often experience heavy rainfall, leading to increased erosion and soil instability. The erosion can weaken soil structures, leading to slope failures, landslides, and foundation instability. Areas with geologically disturbed areas such as clay shale, colluvium, and deformed rock due to relic active tectonic activity are attributed to unexpected failure during construction. While area with problematic soil such as the soft soil zone exhibits large long-term compression and low bearing capacity challenges.

Results. Designing to accommodate the challenges of geologically disturbed areas and problematic soil is crucial to prevent structural damage. Tropical regions also often have high groundwater tables due to frequent rainfall and low evaporation rates. This can pose challenges for geotechnical and structural design as structures may be subjected to buoyancy forces and soil liquefaction during seismic events. Tropical ground requires careful consideration of material properties and behaviour, environmental conditions, and potential hazards. Engineers can solve the difficulties that come with these problematic grounds in tropical areas and guarantee the safety, stability, and sustainability of infrastructure projects by applying suitable geotechnical engineering techniques and mitigating measures.

Conclusions. Case studies about problematic tropical soil and solutions.