Search Results (19)

Field measurements of ground vibrations were conducted along the Paris–Brussels high-speed railway (HSR) to systematically analyze vibration characteristics generated by embankment and cutting sections. Utilizing the 2.5D finite element method (FEM), numerical models were developed for both earthworks to evaluate the influences of design parameters on ground vibration responses. Results demonstrate that train axle load dominates vibration amplitude in the near-track zone, while the superposition effect of adjacent wheelsets and bogies becomes predominant at larger distances. Vibration energy attenuates progressively with increasing distance from the track, with medium- and high-frequency components decaying more rapidly than low-frequency components. The dominant vibration frequency is determined by the fundamental train-loading frequency (f₁), which increases with train speed. Distinct attenuation patterns are identified between earthwork types: embankments exhibit a two-stage attenuation process, whereas cuttings undergo three stages, including a vibration rebound phenomenon at the slope crest. Furthermore, greater embankment height or cutting depth reduces ground vibrations, but beyond a critical threshold, further increases yield negligible benefits. A higher elastic modulus of the embankment material correlates with reduced vibrations, and steeper cutting slopes, while ensuring slope stability, contribute to additional mitigation. Full article

The stability of slopes is a critical challenge in various civil engineering projects, such as embankments, cut-slopes, landfills, dams, transportation infrastructure, and riverbank restoration. Stabilizing slopes using bioengineering methods is a sustainable approach that limits the negative impact of engineering works; such methods should be implemented and adopted worldwide. Geosynthetic materials and plant roots are sustainable for preventing erosion and surface landslides. The plants used for this paper are known to have beneficial effects on erosion control, namely Festuca arundinaceous, Dactylis glomerata, Phleum pratensis, Trifolium pratense, and Trifolium repens. Using vegetation as a bio-reinforcement method is often more cost effective and environmentally friendly than traditional engineering solutions, making a more sustainable engineering solution for shallow slope stabilization applications. The paper presents the erosion process that occurred on sandy slopes protected by organic soil layers and geosynthetic materials under rainfall simulation in scaled model tests. Full article

Asphalt cores in embankment dams are subject to loading and temperature changes during construction and reservoir impounding. Asphalt samples were drilled out from the Quxue Dam and Laojiaoxi Dam cores during construction. The diameter of the samples was 100 mm, and the length was about 450 mm. The samples were cut into specimens measuring 200 mm in length. Long-term triaxial creep tests were conducted on the specimens. The tests were run systematically at different radial confining stresses in the range of 0.5–1.5 MPa and at different temperatures in the range of 5–30 °C. More than 3.5 years were required to complete the tests. Based on the systematic test results and the application of the viscoelastic theory, a material stress–strain–time–temperature creep model (SSTTC) is proposed. The performance of asphalt cores in dams is discussed. The proposed SSTTC model may be applied in the numerical analysis of asphalt cores in dams during dam construction and reservoir impounding. Full article

This paper uses the SPH method to study snow disasters, including the snow flow model of a vertical water diffusion equation and heat balance equation. The advantage of the SPH method is that it can capture particles’ positions, which can be used to track the initial position distribution of hazardous particles. At the same time, a particle modeling method based on pixel value is proposed, which has certain advantages in dealing with the boundary modeling of different materials. In addition, snow disaster prevention and the control of classic embankment and cutting procedures were carried out. The final treatment results showed that the number of snow particles on the subgrade surface was reduced by about 90%. The validity and feasibility of the snow disaster simulation software based on the SPH method are verified by comparison with the experimental results. Full article

A current big challenge for developed or developing countries is how to keep large-scale transportation infrastructure networks operational under all conditions. Network extensions and budgetary constraints for maintenance purposes are among the main factors that make transportation network management a non-trivial task. On the other hand, the high number of parameters affecting the stability condition of engineered slopes makes their assessment even more complex and difficult to accomplish. Aiming to help achieve the more efficient management of such an important element of modern society, a first attempt at the development of a classification system for rock and soil cuttings, as well as embankments based on visual features, was made in this paper using soft computing algorithms. The achieved results, although interesting, nevertheless have some important limitations to their successful use as auxiliary tools for transportation network management tasks. Accordingly, we carried out new experiments through the combination of modern optimization and soft computing algorithms. Thus, one of the main challenges to overcome is related to the selection of the best set of input features for a feedforward neural network for earthwork hazard category (EHC) identification. We applied a genetic algorithm (GA) for this purpose. Another challenging task is related to the asymmetric distribution of the data (since typically good conditions are much more common than bad ones). To address this question, three training sampling approaches were explored: no resampling, the synthetic minority oversampling technique (SMOTE), and oversampling. Some relevant observations were taken from the optimization process, namely, the identification of which variables are more frequently selected for EHC identification. After finding the most efficient models, a detailed sensitivity analysis was applied over the selected models, allowing us to measure the relative importance of each attribute in EHC identification. Full article

The reduction of train-induced ground vibrations by different railway lines and by mitigation measures in the propagation path is analysed in a unified approach by two-dimensional finite element calculations where the reduction is expressed as the amplitude ratio between a specific and the reference situation (the surface track without a mitigation measure). In general, there is no reduction at low frequencies, and the reduction becomes stronger with increasing frequency. A maximum reduction ratio of 0.1 at high frequencies is established with an open trench. Reduction ratios between 0.7 and 0.2 have been found for the other situations, filled trenches, walls, plates, and blocks, as well as for railway lines on embankment, in cuts and in a tunnel. Bridges can produce amplifications due to their resonance frequencies, but also strong reductions due to the massive bridge piers. The influence of some parameters has been analysed, the length of the bridge span, the inclination of the embankment and the cut, and the stiffness of the soil and of the tunnel structure. The dynamic track stiffnesses of a surface, bridge and tunnel track have been calculated by the 3D finite-element boundary-element method for comparison with corresponding measurements. Full article

The international commitment to achieve carbon neutrality in the next few decades has oriented human activities towards the preservation of natural and non-renewable resources. In this context, a great research effort has been devoted to the search for sustainable solutions for the infrastructure construction sector, based on a thorough assessment of the environmental impact (EI). In this regards, Life Cycle Assessment (LCA) is considered one of the main components of Environmental Impact Assessment (EIA) and, for a comprehensive analysis, all the costs incurred by stakeholders during the useful life of the infrastructure should also be taken into account, applying the Life Cycle Cost (LCC) methodology. So far, there is a lack of combined LCA and LCC analyses of railway projects to support a proper sustainable decision-making process at a project level. Therefore, this study aimed to contributed to this topic by determining the environmental effect and related costs of different planning and construction choices in terms of material and maintenance strategies. For this purpose, first, an LCA of typical railway infrastructures with a ballasted track was developed. The case study considered two different functional units of a double-track railway line: 1 km of embankment section and 1 km of a cut section, in straight alignment. After defining five alternative railway infrastructure scenarios with different materials (virgin or recycled material) and construction methods (e.g., lime stabilization), two different railway track maintenance approaches were analysed. SimaPro was used to analyse the case study, and the results were compared with those obtained using the PaLATE software, suitably adapted for use in the railway sector. Finally, a cost analysis was carried out using Life Cycle Cost (LCC) methodology for all the scenarios analysed. The results obtained in terms of EI and related costs of each scenario provide useful information, allowing a sustainable planning approach: as a general result, the initial construction phase always involves the larger part of the total environmental impact while the material production is the most polluting phase, reaching percentages always higher than 50% of the total. Full article

Owing to steep terrain and complicated geology, constructing spur roads with low cost and sufficient strength is crucial for sustainable forest management in Japan. The Shimanto method was developed for making narrow spur roads robust against collapse around the 2000s in the Shimanto geology belt area, where the strata were slanted because of an accretion wedge. Kochi University Forest adopted this method and constructed some routes of spur roads in the 2010s. In the present study, we assessed the performance of this method in terms of the roadbed strength and bearing capacity. Two routes were selected, namely Sites 1 and 2, constructed in 2013–2016 and 2019–2021, and tested in 2017 and 2021, respectively. The roadbed strength was measured up to a depth of 100 cm using a handy dynamic cone penetrometer with a rammer of 5 kg. The results showed that the roadbed strength of the embankment side was weaker than that of the cut slope side, although the method was supposed to compact the roadbeds equally over the road width. However, most of the roadbeds had sufficient strength; the younger ones tended to have lower strength than the older ones, and the same tendency was observed for the bearing capacity. It was suggested that the soil under the road width should be excavated more widely toward the cut slope side before compaction. Full article

Sand is one of the most abundant, naturally occurring materials in many parts of the world, which is used in local rural areas in infrastructure projects such as in the construction of low volume paved and unpaved road layers due to their availability at low cost and scarcity of other suitable construction materials. Several geotechnical solutions for sand stabilization have been undertaken to improve their properties in order to overcome erosion, failure of pavements under traffic loading, embankments, cuts and excavations caused by failures of sand structure. In this investigation, bentonite clay–water slurry was used due to its cohesive and eco-friendly nature to improve sand strength by the means of manual injection in the laboratory and pilot scales. Sand was stabilized using variation of bentonite clay contents, 0%, 1%, 2%, 3%, and 4% (by weight of dry sand), at different curing times: 0 days, 1 day, 2 days, and 3 days. Direct shear tests were conducted to determine shear strength parameters for sand before and after stabilization process. Furthermore, a transparent polypropylene box (60 cm × 40 cm × 30 cm) was used in this study as a larger scale for sand stabilization technique by applying manual grouting of bentonite clay–water slurry to the sand mass. A mechanical shaker was used at 100, 200, 300, and 400 rpm for 10 min at each stage to test the stability of sand in addition to using a Scanning Electron Microscope (SEM) to obtain images for stabilized sand and Ground Penetrating Radar (GPR) to scan soil mass before and after stabilization. The test results showed that a slurry composed of 3% of bentonite clay additive with 10.3% added water by weight of dry sand mass are the optimum amounts for the stabilization process, which provides a substantial resistance to shear forces. Full article

With the rapid development of road engineering today, a large number of high-grade highways need to pass through expansive soil distribution areas. At present, the research on expansive soil slope mainly focuses on the newly excavated cutting slope. However, according to engineering experience, a landslide of fill embankment on expansive soil foundation is also very common. The expansive soil layer is heterogeneous. There are many weak intercalations or large fissures under the ground, which are generally parallel to the trend, with low strength and high permeability. After rainfall, the strength of the weak interlayer and large fissures will be further reduced after moisture absorption, and the sliding surface is easily formed under the load of filler, which is the main factor inducing embankment landslide. On the basis of landslide investigation and a laboratory test, a FORTRAN calculation program is developed in this paper, which can comprehensively consider the special moisture absorption and softening characteristics of expansive soil. Taking a high fill embankment slope with a soft interlayer in the Baoshan area of Yunnan Province as an example, the stability and instability characteristics of the fill slope on the expansive soil foundation are analyzed, and the influence of moisture absorption and softening on the expansive soil slope is emphatically discussed. Finally, this paper puts forward the reinforcement method of the high fill embankment slope on the soft expansive soil foundation, which is proven to have a good reinforcement effect through calculation analysis and field practice. For expansive soil foundation with weak interlayer, it is better to directly reinforce the weak layer through rigid piles. Full article

High-pressure jet grouting is widely used in the construction of cut-off wall in hydraulic engineering. Compared to the high-pressure jet grouting used for foundation improvement, the high-pressure jet grouting cut-off wall of hydraulic engineering has lower requirements for the advance consolidation and provision of bearing capacity, and more focus on providing an anti-seepage effect and ensuring the continuous integrity of the wall. In the past, the research on high-pressure jet grouting focused more on the application to foundation treatments, and the research on the construction efficiency of cut-off wall is relatively insufficient. Therefore, in this study, a self-developed ipsilateral multi-nozzle jet grouting machine with a large drill diameter and construction method are proposed according to the construction characteristics of the embankment cut-off wall in hydraulic engineering. Based on the dyke protection projects, Jinggangshan navigation hydropower and Xingan navigation hydropower, the large-diameter, multi-nozzle, high-pressure jet cut-off wall test is carried out, and the wall forming effect of the cut-off wall is verified through the combination of indoor and outdoor tests. The results show that the proposed construction method can adapt to the formation conditions in which it is difficult to implement conventional high-pressure jet grouting, and obtains good construction efficiency. A favorable wall quality can be obtained by using more efficient large-diameter and ipsilateral multi-nozzle jet grouting in the construction of high-pressure jet cut-off wall. Full article

In recent years, there has been a marked increase in the amount of municipal waste generated in Poland. In the context of circular economy assumptions, the key is the availability of technologies that would make it possible to safely process and reuse waste, especially when it is difficult to manage. One such direction is thermal waste treatment. In 2020, 21.6% of all municipal waste was subjected to this process. Consequently, the amount of ash generated is significant (approximately 2,823,000 tons annually). One of the uses of waste materials is the sealing of earth hydrotechnical facilities, such as flood embankments, water dams, and embankments of waste landfills. For this purpose, cut-off screens made of hardening slurries are used. In order to improve the tightness and corrosion resistance of hardening suspensions, combustion by-products are added to their composition. The article presents an assessment of the possibility of using ashes from municipal waste incineration as an additive to hardening slurries. It also discusses the technological and operational parameters of hardening slurries with the addition of the ashes in question. Binding requirements for hardening slurries used for the construction of cut-off walls is also defined. The experiment showed that the tested hardening slurries meet most of the suitability criteria. Further research directions are proposed to fully identify other properties of hardening slurries in terms of their environmental impact. Full article

Slope failures in high plasticity clay deposits are common occurrences in many parts of the world. In western and central Alabama, expansive Prairie clays are commonly found, and shallow slope failures have occurred in both fill and cut slopes containing these high plasticity clays. The objective of this study was to examine the effects of suction and the use of nonlinear strength envelopes on the embankment stability of a section of highway AL-5. The testing program consisted of fifteen ring shear tests performed using a Bromhead Ring Shear Device. The results of the tests were used to develop both linear and nonlinear fully softened and residual strength envelopes. The saturated strength envelopes are then used in a limit equilibrium slope stability analysis with and without the effects of suction. The results show stability (factor of safety >1) for all cases except the residual friction angle without suction. Given these results, large slope failures are unlikely to occur in this area, but surficial failures and deformations due to creep may be possible. These results demonstrate the importance of considering the effects of suction and nonlinear strength envelopes when examining the potential for shallow slope failures in high plasticity clays. Full article

The mission of botanical gardens is to work towards the conservation and sustainable use of plant diversity. In the case of gardens established on the premises of former manor estates, actions are also being taken to properly manage existing natural resources, e.g., historic tree stands. This article is based on the case study of the Botanical Garden in Lublin. To assess the health condition of the trees growing in the oldest part of the park—Kościuszko Redoubt—sonic tomography examinations were performed. The article presents the practical application of a newer form of digital imaging, put to the service of assessing the health of old trees in an important public space. The Redoubt is the only work of defense architecture in Poland related to the activity of General Tadeusz Kościuszko, the hero of Poland and the United States of America. It has survived in an excellent condition, preserved without significant changes, as an earth structure with ramparts; an interior, i.e., a yard; a cannon post located on an inaccessible cliff; and a brick basement serving as a shelter for soldiers and a warehouse. The entire surroundings also survived: ravines masked with a wild green, embankments with a safe hidden access road to the Redoubt, and a shaped defense line. The Botanical Garden area is located in the Sławinek district, in the valley of the Czechówka River, and includes a fragment of it and the slope adjacent to the west, cut by three loess ravines. The Botanical Garden was established in 1965, where there was a manor farm earlier, and then in the 19th century, a spa that was destroyed during World War I and II. Good soils and a varied microclimate provide the right ecological conditions for the high biodiversity of plants. With an area of 21.15 ha, the Garden area has the character of a landscape park with the theme of a manor garden from the turn of the 18th/19th century and a spa garden. The primary purpose of the work was to investigate the effectiveness of the use of computer tools in the sustainable management of historical greenery in the Botanical Garden. Research has shown that diagnostics with the use of sound waves allow for an accurate diagnosis and quick protective measures against the tree, improving the safety of visitors to the botanical garden. Moreover, the obtained results and a historical query were used to prepare an application to recognize Redoubt as a monument. Full article