Influence of excavation depth on the interaction between barrette and subgrade soil (Moscow)

Abstract

   Barrette is a type of piles used in the construction of high-rise buildings on soft soils, as an additional option of bored piles. It is shown that the use of barrettes activates the search for new ways to improve the design quality of foundations, in particular the development of new calculation methods. The paper analyses the computational results of the interaction between long length barrette and subgrade soil at different excavation depths.   Methodology: The numerical analysis combined with analogy; numerical simulation based on PLAXIS 3D geotechnical software for the elastic-plastic model of hard and soft soils. Comparison and analysis of numerical simulation data on the barrette interaction and bearing capacity.   Findings: Data obtained for excavations of different depths are compared and analyzed. It is evident that piles with greater excavation depth in the considered soil conditions, always have greater bearing capacity and less settlement. The soil bearing capacity can be defined as the barrette load at 40 mm settlement by analogy with in-situ barrette tests. Based on the calculation results, load-settlement plots are given for loading at different excavation depth. It is shown that zones of plastic deformation appear on the lateral surface of the barrette, which is the reason for the settlement growth.   Conclusion: The proposed computational model confirms the research results based on the state standard 22.13330.2016 " Building Foundations". The excavation depth affects both bearing capacity and vertical settlement of the barrette. Further research based on numerical calculations and experimental and theoretical data will allow to develop new calculation methods and increase the efficiency of design solutions.