Abstract #
This paper presents a detailed slope stability assessment for a future development site located in a former clay pit in Budapest, Hungary. The site, which includes weathered clay slopes, was analyzed to calculate the factor of safety using field data and computer modelling. The study employed two different geotechnical codes, Plaxis and GEO4, to model potential slope failures. Plaxis uses finite element modelling, while GEO4 applies conventional calculation methods for circular and polygonal slip surfaces. The analysis identified high pore pressure due to rainwater infiltration and small springs as the main triggers of landslides, with slip surfaces located at the boundary between yellow weathered clay and grey unaltered clay.
Technical Relevance #
This document is essential for geotechnical engineers and professionals involved in urban development and slope stability analysis. The study provides critical insights into the behavior of weathered clay slopes, highlighting the importance of accurate modelling in predicting slope stability and ensuring safe site development, particularly in areas with complex geological conditions.
Target Audience #
The document is intended for geotechnical engineers, civil engineers, researchers, and professionals involved in urban planning and slope stability assessment. It is particularly relevant for those working on projects in regions with weathered clay formations, where understanding the factors that contribute to slope instability is crucial for safe and effective site development.
Software and Methodology #
The slope stability analysis was conducted using two different software programs: Plaxis, which utilizes finite element modelling, and GEO4, which uses conventional methods like Bishop’s method for circular slip surfaces and Sarma’s method for polygonal slip surfaces. The methodology involved field surveys, borehole drilling, and laboratory testing to obtain the necessary geotechnical parameters. The study compared the results from both software tools to evaluate the safety factors and identify the most critical slip surfaces within the site.
Process Description #
The paper begins with an overview of the site’s history as a former brick yard with clayey slopes, detailing the geological and hydrological conditions of the area. The process description includes the field surveys, drilling operations, and laboratory analyses conducted to characterize the soil properties. The study then outlines the modelling approach, including the setup of the Plaxis and GEO4 software to simulate slope stability under various conditions. The analysis focuses on identifying the critical slip surfaces and calculating the factor of safety for different sections of the slope.
Main Findings #
The study finds that the slope’s stability is most threatened by high pore pressure resulting from rainwater infiltration and small springs located within the weathered clay. The analysis using Plaxis and GEO4 software produced similar results, with the factor of safety ranging from 1.6 to 1.7 for the circular slip surface and up to 2.0 for the polygonal slip surface. The research highlights the importance of considering both finite element modelling and conventional methods in slope stability analysis to capture the full range of potential failure mechanisms.
Practical Applications #
The findings from this study are directly applicable to the design and planning of urban development projects in areas with weathered clay slopes. Engineers can use the insights gained from the modelling approaches to improve the accuracy of their slope stability assessments and ensure that site development is conducted safely. The study also provides valuable guidance on the selection of appropriate modelling techniques for different geological conditions.
Limitations and Considerations #
The document acknowledges that the accuracy of the slope stability analysis depends on the quality of the input data, particularly the geotechnical parameters obtained from field surveys and laboratory tests. Engineers should conduct thorough site investigations and consider local geological conditions when applying these findings to their projects. The study also emphasizes the need for continuous monitoring during site development to validate the model’s predictions and adjust the design as necessary.
Conclusions #
The paper concludes that the combined use of finite element modelling (Plaxis) and conventional methods (GEO4) provides a comprehensive approach to slope stability assessment in weathered clay slopes. The study demonstrates the effectiveness of these methods in identifying critical slip surfaces and calculating the factor of safety, offering valuable insights for geotechnical engineers involved in urban development projects. The results underscore the importance of integrating multiple modelling approaches to achieve accurate and reliable slope stability predictions.
Related Resources #
Further reading includes studies on slope stability assessment using finite element methods, research on the behavior of weathered clay under varying stress conditions, and case studies on the application of geotechnical software in urban development projects. Additional resources on the calibration of geotechnical models and the analysis of slope failures can provide deeper insights into optimizing slope stability assessments.
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