The potential damages of low-rise building foundations on liquefiable sites were studied using the Midas GTS-NX analysis. Both free-field and foundation responses for single raft and piled raft foundations were monitored on layered sands using the UBCSand model. It was found that a single raft can be easily uplifted by surrounding groundwater and soil liquefaction occurred. The piled raft foundation has better seismic resistance compared to the single raft. The foundation load will enlarge the ground settlements but reduce the horizontal ground displacements underneath the foundation. The 2D analysis can provide rational predictions of the piled raft responses despite the foundation geometry not being fully simulated. Using a thicker raft can eliminate the angle variable of the foundation. Considerable amounts of foundation settlements were found for single rafts and piled rafts according to the design specification. Longer piles will help to reduce the foundation settlement.

Currently, more and more unique industrial buildings and structures are being built in difficult geotechnical conditions all over the world. One of the most common factors complicating the design of facilities with a high level of responsibility from the point of view of geotechnics is construction in earthquake-prone regions. Seismic impacts lead to a loss of soil stability under dynamic influence and require the determination of nonlinear dynamic properties of soils for the subsequent design of structures on such grounds. To carry out a qualitative and quantitative assessment of the stability of the base of a nuclear power facility under dynamic loads, a series of special laboratory studies was carried out, including dynamic triaxial compression tests and low-amplitude torsional vibration tests in a resonant column. The base was represented by bulk sandy soils, soil samples were tested at full water saturation and in accordance with the regulatory and technical documentation of the Russian Federation. According to the results of dynamic triaxial compression tests, dilution potentials were determined for each of the soil samples taken from a depth of 0.8 to 9.0 m. As a result of low-amplitude dynamic tests performed using a resonant column, the corresponding resonant frequencies, shear modulus, and damping coefficients were obtained for each of the soil samples taken from a depth of 3.8 to 8.0 m. During the research, a computer program was implemented and tested to speed up the processing of test results, as well as improve the accuracy and reliability of the data obtained because of processing. The use of automated tools for processing laboratory test results significantly reduces the time required to complete research and improves the accuracy of processing. The tests performed made it possible to assess the dynamic stability of the projected structure at different intensities of the predicted seismic impact. Based on the data obtained, a computational model was created in the Plaxis geotechnical software complex, in which the behavior of a sand embankment under dynamic loads was modeled. An analysis of the stress-strain state of the base of the projected structure under seismic influence has been performed, considering the soil parameters determined based on special laboratory studies of the dynamic properties of soils. The assessment of the risk of loss of stability of the foundation soils at various levels of seismic impact is carried out based on the initial data on the predicted seismic impact.

One method for effectively utilizing the unsuitable soil that is generated at construction sites is to improve it by solidification. This method is reliable, as it causes strength to develop over time. The shape of the embankment is toe of slope of the embankment is thinnest and thickest towards the top of slope, so the greatest load acts on the center of the embankment. For this reason, when an embankment is constructed on soft ground, the center of the embankment will settle the most and the bottom of the embankment will be subjected to tensile stress. Unsolidified soil will gradually follow the deformation of the ground even when subjected to tensile stress, but embankments made of solidified soil will not be able to withstand the tensile stress caused by settlement and will crack. If the embankment is a river levee, there is the risk of water leakage through these cracks. The plains of Hokkaido, Japan, are widely distributed with peaty soft ground. When river levees are constructed using solidified soil on such ground, similar issues can occur. Crushed solidified soil is a material created by crushing solidified improved materials after they have undergone a certain period of strength development. This material is compactable and exhibits only a small strength increase after compaction. Previous studies have investigated the geotechnical properties of crushed solidified soil. In this current study, to understand the strength characteristics of crushed solidified soil, a one-year investigation was conducted on compacted lab specimens and embankments constructed in the field using this material to examine the relationship between elapsed time and strength. The lab specimens were found to exhibit a certain increase in strength over time. It was confirmed that the embankment material had a low degree of solidification and that the material aggregated into small clumps of soil. These results show that embankments made of crushed solidified soil exhibit low strength development, making such soil a suitable material for constructing embankments on soft ground.

It has been widely reported that reliquefaction engenders under smaller seismic events than previous liquefaction. Once a sand undergoes liquefaction, the initial sand’s fabric (skeleton structure) formed during sedimentation process will be completely destroyed and changed during liquefaction and re-sedimentation process. Therefore, reliquefaction resistance is influenced by not only density but also structure change. To fully understand the mechanism of reliquefaction, this study focused on effects of sand particle orientation on deformation characteristics of sand in small to large strain range. The specimens were prepared using Toyoura sand with three initial depositional angles of 0°, 45°, and 90°. Then, two kinds of mechanical tests, those are bender element (BE) tests to measure initial shear modulus (G0) and local small-strain (LSS) tests to obtain secant shear modulus at various strain range were conducted using a triaxial apparatus. Two types of specimens, which are before liquefaction (without liquefaction history) and after liquefaction (with liquefaction history), were used in those tests. The particle orientations before and after liquefaction were measured using an image microscopy. The results obtained are follows. The BE tests showed increased G0 with increase of initial orientation angles (0° to 90°) before liquefaction. However, this trend became indistinct after liquefaction. Microscopic analysis for the particle orientation revealed that particle orientation tended to concentrate on 90° orientation in all cases after liquefaction. LSS test results additionally indicate degradation of secant G (Gsec) with shear strain is greater in the specimens with larger orientation angles. Those deformation characteristics had close relations with sand particle orientation.

The purpose of the study is the geotechnical substantiation of methods for the protection of underground, linear structures operated for a long time in difficult engineering and geological conditions, taking into account the combined effects of external forces and internal environmental influences. Taking into account the specifics of the set goal and the complexity of engineering and geological tasks, their achievement is proposed to be solved by modeling the interaction of underground aquifers with the host soil mass under the influence of external forceful static and dynamic influences. A calculation justification is given and methods for strengthening and protecting tunnel structures under various combinations of extreme force and dynamic impacts during train movement are presented. In order to take into account the specifics of the operation of sewer tunnels in difficult ground conditions, revealed as a result of instrumental, hydraulic and engineering-geological surveys, modeling of the interaction of underground reservoirs with the host soil based on geotechnical calculations (Plaxis 3D) was performed. As a result of the simulation, design situations were developed that take into account the most unfavorable conditions that may arise when force and dynamic loads are applied to linear underground structures. Based on the modeling results, an integrated approach to the choice of methods for protecting structures is proposed, and a calculated justification for their structural reinforcement is given. The implementation of the proposed methods of strengthening and protecting underground linear communications was successfully tested during the reconstruction of Russian Railways station facilities.

This study evaluates the load-bearing capacity of pile foundations, with a focus on those used in the “Multifunctional complex”. The objective of the field tests was to determine the bearing capacity of two driven piles, Nos. TR7 and TR18, type C9.30, installed to depths ranging from 4.1 m to 3.5 m, with final shaft elevations of 340.51–341.34. In addition, one driven pile No. TR34, type C11.30, was installed to a depth of 3.6 m. Two test piles of grade C9.30 (TR7 and TR18) and one test pile of type C11.30 (TR34) were subjected to load testing. Driving operations were performed on July, 2021, using a Juntan PM-25 pile-driving rig equipped with an NNK-5A hydraulic hammer weighing 5000 kg. Field load testing was conducted after a pile “rest” period of 28 days following installation. The load-bearing capacity of the pile according to the results of static load tests on the above-mentioned site of construction amounted to 799 kN.

This paper discusses the issues of modeling swelling soils and their implementation in the finite element program. The main emphasis is on the choice of a mathematical model that best allows you to make correct and accurate calculations in such complex soils as swelling. Based on the results of the comparison, the most suitable model was implemented in the Plaxis 2D program. Despite the wide prevalence of swelling soils, design methods have many differences and are not reduced to a single standard that allows you to reduce costs at the design stage. The complexity and variety of conditions for constructing a foundation on swelling soils force engineers to resort to solving each problem separately. New global trends and conditions are changing the established order of things even in construction. The new approach outlined in the study will help to solve this problem with greater ease and accuracy. Based on laboratory data, modeling of foundations on improved expansive soils with lime and polypropylene fiber, allowed us to come to conclusions that significantly improve the behavior of foundations on swelling soils and simplify their design, which opens the possibility of using the research results and the calculation model in engineering practice.

The study is focused on the increasing transition from laboratory soil testing to advanced in-situ methods, which is particularly relevant due to the difficulty of obtaining undisturbed natural samples for large-scale engineering projects. At the same time, laboratory investigations remain essential for scientific research and calibration of field data. The main objective of the work was to describe the operation principles, measurement capabilities, and practical applications of the Marchetti Flat Dilatometer (DMT), as well as to present the upgraded Seismic Dilatometer Marchetti (SDMT) equipped with a module for measuring shear wave velocity (Vs). The research methodology included experimental field measurements, observational studies, and comparative analysis supported by data interpretation techniques. These methods allowed obtaining reliable and practically significant information on soil behaviour underload. The results demonstrate that the Marchetti dilatometer is suitable for testing a wide range of soil types, from loose and soft clays to dense sands and soft rocks. DMT provides stable and accurate results even in very soft or highly over-consolidated soils. The obtained parameters can be effectively used for prediction of foundation settlement, evaluation of compaction quality, assessment of cyclic liquefaction resistance, and control of geotechnical improvement processes. The introduction of the seismic module considerably expands the capabilities of the device, allowing simultaneous determination of shear wave velocity and stiffness parameters crucial for seismic site characterization. Correlations established between DMT indices, deformation modulus, and liquefaction resistance confirm the applicability of DMT/SDMT data for integrated geotechnical and seismic analyses. The study concludes that the Marchetti dilatometer, especially in its seismic modification, is an efficient and informative tool for field soil investigations, offering a reliable basis for engineering decision-making in design, monitoring, and ground improvement quality control.

A distinctive feature of the geological structure of the regions of southern Kazakhstan are weak ground deposits with a thickness of up to 20 meters or more, water saturation of the surface layers of the base with groundwater or surface waters and high seismicity up to 10 points on the MSK-94 scale. Construction in such conditions requires a set of measures to strengthen the foundation and improve the mechanical properties of the foundation soils. Soil hardening is performed with DSM cement columns of a certain diameter and a step of arrangement along the reinforced array. Such hardening changes the seismic properties of the base and, accordingly, the joint operation of the structure with the base soils in comparison with the non-hardened base soil. The article presents data on the propagation velocities of transverse and longitudinal waves in natural and reinforced substrates. Data on the wave propagation velocities in the column material used to strengthen the base are presented. The data of geophysical studies on the measurement of wave propagation velocities in an unconstructed and hardened massif are presented. It is shown how, depending on the number of reinforcement elements and their arrangement patterns in the reinforced array, the propagation velocity of transverse and longitudinal waves can change. It is shown how and to what extent the rigidity of the hardened massif and the seismic properties of the soils of the hardened base change. The MIDAS GTS NX provides an example of using the DSM column reinforcement method and an approach to determining the dynamic properties of a reinforced base to calculate the bearing capacity and operational suitability of a building or structure under seismic influence.

Nowadays, due to the increase in the number of storeys of structures under construction, the number of buildings erected on pile foundations has increased. A large number of theoretical and experimental studies of pile operation under load have allowed the development of various methods for calculating pile settlement. However, most of them do not take into account the technology of pile construction, which affects the change in the properties of the contact zone soils. In addition, most of the methods assume that the settlement of the pile is equal to the settlement of the soil, but in reality, after reaching the ultimate strength, the pile has the possibility of slipping through the soil. The main purpose of this paper is to investigate the influence of the interface friction coefficient (strength reduction factor Rinter) on the results of pile settlement calculations performed by numerical method in the geotechnical software package Plaxis. In this paper, the interface friction coefficient was determined from the results of laboratory shear tests of sandy and clayey soils over concrete, in accordance with the current regulatory documentation (SP 22.133330.2016 «Soil bases of buildings and structures») and back calculation based on field tests. Based on the results of the calculations, graphs of load-dependent settlement were plotted and a comparative analysis of the results obtained with the results of known field tests of bored piles by static loading was performed. Based on the comparative analysis, conclusions were drawn about the influence of the method of determining the interface friction coefficient on the pile settlement calculation results, the influence of the pile construction technology on the interface friction coefficient value and recommendations on how to take this coefficient into account in the calculations.

The Shymkent city, located in the south of Kazakhstan, has become a megalopolis. The population and traffic intensity on roads of the city are growing, which outpace the rate of increase in road strength. The traffic flow contains public transport with a large capacity and heavy trucks. The climate of the region is characterized by a long hot period. The above factors caused the appearance of rutting on asphalt concrete road surfaces in the city. This paper studies rutting on city roads with asphalt concrete pavement. In field conditions, the characteristics of rutting and influencing factors were determined.

This study investigates the horizontal prestressing effects induced by stone column installation, with particular focus on displacement-based methods performed without or with minimal predrilling. These methods, commonly implemented as dry bottom-feed vibro-displacement techniques, are widely applied in engineering practice across a broad range of soil conditions, including granular, silty, and cohesive soils. Using advanced three-dimensional numerical modelling and critical evaluation of existing literature and analytical procedures, this study examines how installation-induced lateral stresses influence the geotechnical performance of soils.The research focuses on three key aspects of ground improvement: settlement reduction, bearing capacity enhancement, and liquefaction resistance. Analysis highlights the significant differences in stress transfer mechanisms and soil-structure interaction between Low-Confinement Stone Columns (LCSC) and displacement-based installations. Displacement methods such as vibro-displacement were shown to substantially increase horizontal stresses in the surrounding soil, resulting in markedly improved ground performance.In addition, we review and assess the limitations of current design approaches used for settlement analysis, stability checks, and liquefaction evaluation. The findings underscore the need to incorporate horizontal prestressing effects into geotechnical design practices to avoid underestimating and overestimating performance, and to develop more accurate, installation-informed design strategies for stone column-improved ground.

In this study, the dynamic stability assessment of underground structures under seismic loading is carried out by combining the back analysis of rock mechanical parameters with a case study of the Oya tuff underground quarry in Japan. The modulus of elasticity and Rayleigh damping coefficient of the Oya tuff were obtained by inversion of the field shock vibration test, and the FLAC3D three-dimensional numerical model was constructed to simulate the dynamic response under the action of the 2024 Ibaraki earthquake (M5.3). The results show that the deformation near the seismic wave input point is significant; the persistent stress concentration exists at the corner of the pillar base, which is easy to trigger plastic deformation. A dynamic stability assessment framework integrating the plastic zone ratio, displacement field and stress concentration factor is proposed to provide a theoretical basis for pillar foundation reinforcement and roof monitoring. The study verifies the reliability of the inversion parameters for seismic performance assessment of underground structures, which provides technical reference for similar projects.

This paper examines the features of calculating the seismic resistance of a continuous monolithic highway overpass. The study focuses on a 120-meter-long three-span continuous monolithic highway overpass located in an 8-point seismic intensity zone in the city of Jizzakh, above the Tashkent-Samarkand high-speed railway line (Republic of Uzbekistan). The results of calculations for changes in normal stress in the upper and lower parts of the span structure elements of the continuous monolithic overpass, performed using the SHARK and MIDAS Civil software packages, are presented. As a result of the numerical calculation of the seismic resistance of the continuous monolithic overpass, taking into account the interaction between the soil and the foundation of bridge structure, it was revealed that the overpass retains its operational characteristics during an earthquake with an intensity of 8 and 9 points.

Construction activities in Slovenia generate significant amounts of waste, primarily from excavated soil and the demolition of existing structures. The reuse of construction waste is a key aspect of sustainable construction, but its implementation poses numerous challenges. Excavation, a fundamental stage of construction projects, often results in large surpluses of clean or slightly contaminated soil. On a societal level, these surpluses become significant, especially when considering the dredging of sediments from rivers, lakes and marine areas. Additionally, the demolition of buildings produces considerable waste that requires proper processing to be transformed into reusable materials. Although the benefits of reusing construction waste are widely recognized, there are several barriers to its widespread application. These include legal, organizational, logistical, and technical challenges. Regulatory barriers arise from complex legislation and the lack of clear guidelines for the reuse of excavated soil. Organizational issues arise from the need for comprehensive planning, contractual agreements, and alignment among stakeholders. Logistical constraints involve transportation, storage and the coordination of supply and demand for secondary materials. Implementation challenges are related to the lack of standardized testing procedures to assess the geochemical and geotechnical properties of materials intended for reuse. This paper presents a framework for the reuse of construction waste in pavement structures and proposes solutions to overcome these challenges. The analysis and structural design process includes data collection, target definition, determination of structural elements, consideration of environmental and technical conditions, formulation of optimal technical solutions, and selection of the best solution based on economic, environmental, and technical criteria. The successful reuse of construction waste as a valuable secondary raw material in modern construction requires close collaboration between regulatory authorities, investors, designers, and contractors. Only through coordinated efforts can Slovenia fully exploit the potential of construction waste for sustainable development.

Unbonded sections may occur at various points along the length of fully grouted rock bolts. This research explores the condition assessment of these bolts through acoustic wave analyses and controlled model experiments. Rock bolts with varying lengths of unbonded sections were embedded in a concrete block. Hammer strikes were applied to the bolt heads to induce longitudinal vibrations in the rebars. The resulting acoustic signals were measured by a microphone, and their frequency characteristics were subsequently analyzed. It was observed that a longer unbonded section corresponded to a reduction in the dominant frequency of the longitudinal mode. This study demonstrates that the structural soundness of fully grouted rock bolts can be effectively assessed using microphone measurements and analysis of vibration frequency responses.

In such megacities as St. Petersburg, the development of urban areas is not possible without the construction of existing historical buildings. For the construction of foundations and underground parts of buildings, deep excavation pits have to be designed. In such circumstances, the main task of the successful implementation of the project is to ensure the safety of neighboring buildings. For St. Petersburg, for example, the search for a solution to the conditions of safe construction is associated with an assessment of the deformability of the foundation soils under various kinds of technological construction impacts. We have analyzed various methods of geotechnical protection of buildings and structures based on practical experience, depending on a combination of factors. Numerical calculations performed using the PLAXIS software package make it possible to predict with sufficient accuracy the degree of impact of excavation of the excavation pit and its loosening on nearby buildings, taking into account the proposed protective measures. The article discusses practical examples of the use of various active and passive geotechnical protective measures in the groundwater conditions of St. Petersburg, as well as possible consequences in the event of their absence. For the construction of a geotechnical barrier, it is necessary to use modern materials that reduce the time of standing and accelerate the strength gain of the fixed soil mass.

Nowadays various dynamic loads including pile sinking, vibropiling and intensive traffic circulation have a considerable effect on subsoils in case of modern urban development. Dynamic effects might cause additional settlements of foundations of already built structures surrounding a building site. It has been established that dynamic loading leads to liquefaction of sandy soils in certain cases. For this purpose, the experimental research of soil behavior under dynamic effect is a relevant objective.The article deals with integrated laboratory study of the sandy soil samples of different fineness and dry density under the conditions of triaxial dynamic compression. The experiments were performed with a modern dynamic triaxial compression unit, which allows to simulate various modes of static and dynamic loadings of soil samples. As controlled variables in the research vertical and horizontal static stresses ratio, frequency and amplitude were considered. The degree of soil deformation characteristics dependence of particle size distribution and water-saturation degree in case of dynamic loading is specially noted. Critical values of dynamic stresses were obtained. Changes in the soil sample's structure and strain accumulation caused with dynamic dresses were taken into account. The results of the research are presented in a graphical form. Due to the results of the research practical recommendations on building sustainability assessment in case of dynamic loading are given. The veracity of the results is verified with the massive volume of data, that was gotten during the experimental research. Precision of experimental and calculation results has been observed. The results of the research might be applied by civil engineers in foundation design in case of dynamic loading and development of activities for engineering protection of vibration effects.

Tropical soils, particularly in Southeast Asia, present significant geohazard challenges due to their intricate mineralogy and variable properties. This paper evaluates the impacts of weathering, disintegration, and shear failure, employing field investigations and laboratory testing to assess soil behaviour under extreme conditions. Key findings reveal that heavy rainfall and rapid urbanisation heighten the risks of slope failure and foundation instability, thereby complicating hazard mitigation efforts. The research underscores the need for enhanced site characterisation and advanced engineering solutions that consider the unique characteristics of tropical soils. Implications for engineering practices emphasise the importance of adopting specialised geotechnical methodologies for design and construction in these regions.

The development of methods for the construction of foundations for buildings and structures using bored-injection piles allows expanding the scope of their application in seismic areas, as well as in complex and especially complex engineering-geological conditions. In this article, bored-injection piles are understood as piles formed in boreholes by injecting fine-grained concrete mixture under pressure through a hollow rod with a perforated drill bit at the end. The disadvantage of such piles in sandy clay soils is the limited bearing capacity of their upper part for the action of horizontal seismic loads and limited crack resistance of the reinforced concrete body. This is explained by the absence of a spatial rigid reinforcement cage or continuous external reinforcement in the pile. The role of reinforcement in these bored-injection piles is performed by a small-diameter (up to 103 mm) hollow metal rod located in the center of the cross-section. In this case, the upper section of the pile does not work effectively in resisting the reinforced concrete section to horizontal seismic loads. The proposed bored-injection piles differ from the known ones in that a reinforcing element made of a hollow metal pipe with a diameter of 0.3-0.4 meters is made in their upper part. To connect the hollow metal pipe with the underlying small-diameter metal rod, a screw-on transition coupling with a diameter equal to the diameter of the hollow metal section to be connected above is used. After installation, the hollow pipe is filled with concrete, and reinforcement bars are placed inside to subsequently form rigid connections with the body of the grillage or foundation slab of the building. This reduces bending deformations of the pile and achieves the required load-bearing capacity both in terms of material and soil during earthquakes.

The Press-in Method is a static installation method for sheet piles and pipe piles. It secures a reaction force from previously installed piles, and provides a spatially efficient piling work without the need of additional temporary works, even on slopes or above the water. The method has been applied to various projects such as the functional upgrade of the existing structures, restoration of geotechnical structures damaged by heavy rain or earthquakes, disaster prevention and mitigation, prevention of landslide and others. Along with these applications, there has been a growing need for sophisticated methods of design and construction control. This paper reports a series of field tests which were conducted for sophisticating the current construction control method for a penetration technique called the Rotary Cutting Press-in (RCP) Method, where a pipe pile with base cutting teeth is pushed and rotated at the same time. Sixteen sets of installation tests and the rapid loading tests were conducted on the RCP piles with the outer diameter of 1000 mm in dense sands and gravels, by using an actual RCP piling machine and a newly developed spatially effective rapid loading test device. As a result, the effects of the axial loading without rotation at the end of installation and the air injection during installation on the pile capacity were confirmed to be limited, and the pile capacity estimated from the RCP piling data were shown to provide a lower bound for the capacity obtained by the rapid loading test.

Intense rainfall is a primary trigger for slope failures and landslides, posing significant challenges to geotechnical stability. While various reinforcement measures have been extensively studied to mitigate rainfall-induced slope failures, innovative approaches are still needed to address these issues effectively. Recently, biomineralization technology has emerged as a promising technique. This approach leverages bacteria or enzyme-induce urea hydrolysis to induce calcium carbonate precipitation, which enhances soil strength and stiffness while reducing permeability, offering a low-carbon and environmentally friendly solution. In this study, the concept of using urease extracted from soybeans to activate biomineralization was proposed for mitigating rainfall-induced slope instability. Simulated rainfall experiments were conducted on slope models with multi-sensor monitoring system. The failure mechanisms and internal moisture migration characteristics of slopes before and after biotreatment under extreme rainfall conditions were studied and compared. The results reveal that rapid increases in moisture content and pore water pressure due to rainwater infiltration are the main causes of slope failure. The biotreatment effectively established a rainwater shielding system, suppressing rainwater infiltration. During simulated rainfall test, the biotreated slope exhibited slower increases in moisture content and pore water pressure compared to the untreated slope. Furthermore, the onset of slope failure was delayed in the biotreated model. This study provides valuable insights into the application of biomineralization technology as a novel strategy to mitigate slope failure under extreme rainfall conditions.