Methods of estimating surface settlement during driving of urban tunnels

Abstract

When urban tunnels are driven, settlement of the daylight surface is one of the forms of deformation experienced by the soil mass. This process is investigated by the following methods. Empirical methods make it possible to describe the displacement distribution of the daylight surface of a soil mass using certain experimentally established coefficients. Gauss' curve [1], which has two important parameters (maximum surface settlement S max above the axis of the tunnel, and distance i to the inflection point of the surface-settlement curve) is used to describe the surface-settlement profile of a single-barrel tunnel. Peck's formula and several empirical formulas in which the dimensions of the settlement basin are determined primarily by the depth of embedment Z 0 of the tunnel and its diameter D alone are presented in Table 1.Basic inadequacies of the empirical methods are as follows: low accuracy; disregard of equations of state of the materials; impossibility of evaluating the displacement and stress within the soil mass; and, impossibility of compiling a prognosis for newly designed structures.Analytical methods based on positions of the theory of elasticity are presented in [2][3][4]. Sagaseta [3] has developed a solution in closed form for an isotropic uniform incompressible soil (Poisson's ratio of 0.5). Here, has considered only the radial compression of the tunnel section in an elastic half space. Verruijt and Booker [4] analyzed two forms of tunnel deformations -radial compression of the section, and variation in the shape of the tunnel in compressible elastic soils (Poisson's ratio of less than 0.5). Loganathan and Poulos [2] considered the internal friction of the rocks spanning a tunnel. Their analytical solution includes Poisson's ratio, the depth of embedment of the tunnel, and its diameter. The analytical solutions are suitable primarily for rocks. They do not allow for consideration of the conditions under which the rock occurs, the presence of water-bearing seams, the construction phases, and other factors.In contrast to the analytical solutions, numerical methods make it possible to account for a multitude of factors describing the "soil-mass/tunnel" system, including the mutual effect of several tunnels.Methods of estimating surface settlement during the driving of tunnels are described. A combination of empirical, analytical, and numerical methods makes it possible to predict the dimensions of a settlement basin. In the course of solving the inverse modeling problem, parameters of the model are established and forecasting charts of maximum surface settlement are compiled.

Deep Learning Neural Network Model for Tunnel Ground Surface Settlement Prediction Based on Sensor Data

“…Zhao [18] used recognized analytical methods to calculate the lining force and deformation of shallow tunnels and deep tunnels. Strokova [19] investigated settlement prediction methods based on traditional models during tunnel construction. Ercelebi et al [6] used the Plaxis finite element program to predict the settlement by the finite element method, and the results showed that the finite element model can predict the shortterm surface settlement well under a given volume loss value.…”

Evaluation of Building Displacement Induced By EPB Tunneling Through GPS-GNSS Monitoring System and Back Analysis Technique (Tabriz Subway Twin Tunnels)

“…Thus, the observing of settlement that occurs due to tunneling in urban areas is an essential issue. The surface settlement can be estimated by using various approaches such as empirical or semi-empirical methods (Peck, 1969) [1], analytical methods (Loganatan-Poulos, 1998) [2] and numerical methods [3,4]. These studies are based essentially on geotechnical soil features and working peculiarities (e.g., excavation geometry and methodology).…”