# Simple settlement prediction in machine tunnelling

## Contents

Introduction:

Main parameters:
Point of inflection “i”:
Ground Stiffness “E”

Method explained with two Examples:
Example 1: Bangkok clay.
Example 2: Germany unweathered solid Rock.

Critical consideration and Conclusion:

References:

## Introduction:

The following text is about the settlement forecast in machine tunneling with a simple empirical method which is designed by the author. For the design of the method EPB headed tunnel projects with 23 measurements sections where taken into account. The sections which where analysed are in Germany in unweathered solid rock, in clay- sandy Bangkok ground in Thailand and in Italy/ Milano with sandy- gravel ground.

The main parameters for empirical settlement prediction are for author purposes the point of inflection known as “i” and the ground stiffness known as “E”, both were explained followed. To get a settlement trough it is important to calculate the peak “Sv max”. With it and the correct "i" the trough can be very well descriped with the gaussian function. Fillibeck & Vogt (2010)

The method is explained with two examples in several geology. At the end there are given some critical considerations and conclusions to the presented procedure.

## Main parameters:

### Point of inflection “i”:

The parameter “i”, the point of inflection, one of the important parameters takes mainly account in the calculation during the prediction of the maximum vertical settlements “Svmax” and for the characterisation of the settlement through especially for the transversal trough.

Based on the Gaussian normal curve of distribution the point of inflection is the standard deviation. It describes the width of the normal curve und takes main influence of the tangents gradient which is important to considerate in cause of building damages.

For the presented method two possibilities to get a value for the point of inflection where shown after:

- Peck (1969)
- Fillibeck & Vogt (2010)

- Peck (1969)

illustration not visible in this excerpt

Figure 1 Peck diagramm to determine “I” (Peck 1969)

- Fillibeck & Vogt (2010)

Cohesionless Grounds

i loose - middledense: 0.25-0.5*z (1)

i middle- dense: 0.4- 0.6*z (2)

Cohesive Grounds

i Soft - stiff: 0.3- 0.6*z (3)

i Stiff - semisolid: 0.5- 0.9*z (4)

The upper equations are described with “z” as the overburden over the top of the tunnel and with “D” as the tunnel diameter. To get the point of inflection “i” the literature recommend the Peck-Method (Nellesen 2005) but also Fillibeck & Vogt (2010) fitted in own calculations of the author well and can be recommend by similar geology as they taken into account during their researches.

12 of 12 pages

Details

Title
Simple settlement prediction in machine tunnelling
Author
Year
2010
Pages
12
Catalog Number
V149067
File size
486 KB
Language
English
Tags
Setzungen, Tunnelbau, Settlements, Tunneling
Quote paper
M.Eng., Dipl.-Ing. Michael Frahm (Author), 2010, Simple settlement prediction in machine tunnelling, Munich, GRIN Verlag, https://www.grin.com/document/149067