In the bustling heart of Shanghai, where towering skyscrapers and sprawling infrastructure projects are a testament to rapid urban development, a team of researchers has unearthed a critical advancement in excavation engineering. Led by Dr. Gu Xiaoqiang from Tongji University’s Department of Geotechnical Engineering, the team has developed a novel method to determine the proportional coefficient of horizontal subgrade reaction (m), a key parameter in calculating the deformation of retaining walls in excavations. Their findings, published in *Yantu gongcheng xuebao* (Chinese Journal of Geotechnical Engineering), promise to enhance the precision and efficiency of deep excavation projects, with significant implications for the energy sector and urban construction.
The method for beams on elastic subgrade is widely used to calculate deformation in excavations, but the range of m values recommended in existing design codes is broad and doesn’t account for soil properties or excavation dimensions. “This lack of specificity can lead to inaccuracies in deformation calculations, potentially compromising the safety and stability of excavation projects,” explains Dr. Gu. To address this gap, the research team conducted extensive numerical analyses using the Hardening Soil Small-strain (HSS) model and appropriate soil parameters. By varying excavation dimensions and void ratios, they gathered a wealth of data and performed inverse calculations to propose an empirical formula for m.
The team applied this method to 25 excavation projects in Shanghai, determining the m values for the city’s clayey soils and calculating associated deformations. The results were impressive: the calculated maximum horizontal displacements of retaining walls closely matched the measured ones, with an average error of just 2.6%. “This level of accuracy is a game-changer for the industry,” says Dr. Zhou Hechen, a co-author of the study. “It allows engineers to predict excavation behavior more reliably, optimizing design and reducing the risk of costly over-engineering or, worse, catastrophic failure.”
For the energy sector, where deep excavations are often required for infrastructure projects such as power plants, pipelines, and renewable energy installations, this research offers a valuable tool. Accurate deformation calculations can lead to more efficient use of materials, reduced construction costs, and enhanced safety. Moreover, the method developed by Dr. Gu and his team can be adapted to other regions, providing a much-needed reference for engineers worldwide.
The implications of this research extend beyond immediate commercial impacts. As cities continue to grow and infrastructure demands increase, the ability to predict and control excavation deformations will become ever more critical. “This work is not just about improving a single parameter; it’s about advancing our understanding of soil-structure interaction and enhancing the resilience of our built environment,” Dr. Gu asserts.
With their innovative approach, Dr. Gu and his colleagues have set a new standard for excavation engineering. As the industry grapples with the challenges of urbanization and infrastructure development, this research offers a beacon of progress, illuminating the path toward safer, more efficient, and more sustainable construction practices.