Assessing the impact of the process of constructing foundation pit enclosure structures on surrounding building

Abstract

An important issue in the calculations of retaining structures of pits and their interaction with the foundation and existing structures is taking into account the features of their installation technology. Quite often, during calculations, this factor is ignored or taken into account by introducing correction factors, which are somehow based on the statistical processing of observation data during the construction of similar objects.
 The development of numerical methods has enabled designers to use detailed finite-element models in calculations to more accurately predict the behavior of bases and structures, without spending excessive amounts of time.
 In this work, numerical modeling methods are used to reproduce the process of installation of the pit enclosure structures using the trench method "wall in soil" to determine its impact on existing buildings. For this, a numerical model of a 9-floor building with a soil massif was created. Modeling of the foundation pit and enclosure structures, which is installed next to the building, was done. At the same time, the use of a three-dimensional formulation of the problem made it possible to take into account the length of the wall panel and the technological sequence of the construction.
 The existing methods of trench excavation modeling were analyzed and one of them was implemented in the calculation scheme.
 The impact of various factors on the formation of additional deformations of the existing building was investigated, such as: L - distance from the foundation pit to the building; Нст - the depth of laying the sole "wall in the ground"; Lзхв - the length of the wall panel; ρг.р - is the density of the clay slurry.
 Within each task, the settlement of the foundation of the building is determined with different input parameters: L={1,2; 3; 5; 10m}, Нст={12; 18; 24m}, Lзхв={3; 4; 5m}, ρг.р={1.05; 1.10; 1.30t/m3}. The results are presented in the form of graphs.
 The results of the research show that the most determining factors affecting the «technological settlements» of the slab foundation of the building are the distance from the pit to the building and the depth of laying the sole of the "wall in the soil". With different combinations of these parameters, the values of calculated vertical deformations of the building can differ up to several times.