Operational Geodetic Check of Bottom-Hole Zone Deformations at Innovative Tunneling Technologies

Abstract

Purpose: To consider the issue on performance of operational control of deformations of tunnel bottomhole zone with the use of ground-based laser scanning technology when tunneling with New Austrian tunneling method which is the most progressive one and feasible in economics terms for underground building construction by mining. The essence of this method is in that as a support for tunnel bottom-hole zone, a self-supporting shell made of sprayed concrete without traditional fastening method usage is applied that allows to save time for tunneling significantly, especially of those tunnels which have complex geometry and non-standard dimensions. At the same, the conceptual basis for this method is the necessity to identify operatively bottomhole zone soil mass deformations that’s justified by the need to provide job realization safety. Methods: As a major method for to determine tunnel bottomhole zone geospatial position it is proposed to consider ground-based laser scanning technology. Scanning result processing was implemented in specialized software package Leica Cyclone 3DR. Results: Existing experience of geodetic check of deformations in tunneling by New Austrian method is considered. Processing results for data on ground laser scanning of a tunnel separate fragment are presented, a tunnel mathematical three-dimensional model is obtained and assessment of deviations of tunnel actual surface from obtained theoretical one is fulfilled. Practical significance: The obtained threedimensional model can be further used for geodetic monitoring of deformations. Theoretical bases for estimation required accuracy for deformation characteristics definition are substantiated which are based on the transition from construction tolerances to average quadratic errors of deformation characteristics definition and then to average quadratic errors of coordinates for laser scanning points. The enlarged stages of scanning are defined with view of tunneling technology of New Austrian method.