Settlement prediction for protected buildings nearby deep excavation

Abstract

Increasing demand on new spaces in cities due to restrained urban conditions dictates development of underground construction including excavation of deep pits. So there is a need to prevent negative consequences caused by changes in a stress-strain condition of soil mass and additional settlement of foundations with underlying soil. A decrease in excessive settlements of building and their difference could be achieved by protection of a building with implementation of mitigation measures. The goal of the paper is to provide a method of settlement prediction for adjacent buildings in a zone of deep pit excavation for mitigation measure – underpinning of foundations with micropiles. Different factors affecting the settlement value (of building with micropiles) were considered. These factors are the distance from pit edge to a building, geology type, depth of excavation, height of the building etc. Also variation of settlement along a building was taken into account. A series of numerical experiments was conducted modelling these conditions. By methods of statistical analysis empirical equations were obtained allowing to predict the settlement of adjacent buildings underpinned with micropiles. These equations serve as a base for method aimed to determine building settlement in a zone of deep excavations impact with micropiles installed, also considering technological settlement. Technological settlement values were taken from similar case histories. Settlement prediction with the use of obtained equations could be useful at initial design phase to evaluate the use of micropiles to ensure permissible additional settlement values of adjacent buildings in a zone of deep excavation impact.