Determination of the excess excavation ratio from the data of geodesic monitoring

Abstract

Introduction: During constructing tunnels by trenchless method using the shield driving method soil surface subsides. Buildings and structures which fall into the zone of influence of new construction receive additional settlements. To determine it in the calculations it is necessary to take into account the excess excavation ratio. The purpose of the study is to determine the excess excavation ratio for increasing the sample and determining the normative values of the ratio for application in design.Materials and methods: in the article there is examines the construction of a tunnel in the city of Moscow. Calculations are carried out using the PLAXIS software package in two-dimensional and three-dimensional formulations. In the calculations the normative excess excavation ratio was included and a backward calculation was also carried out in order to determine the actual excess excavation ratio according to the data of geodesic monitoring. Results: the results showed that the excess excavation ratio varies from 0.1% to 1.2%. It is much less than the values that are included in the project according to the regulatory documentation.Conclusions: due to the fact settlement is less than the calculation settlement, the cost of building tunnels can be reduced by reducing the cost of protective measures for buildings and structures, as well as reducing the number of buildings that can receive excess settlement.