PAT TBM Improving

A case of study to Mêtro São Paulo

by:

D. Agnella GETAD Consult, São Paulo, Brasil

W. J. Giannotti, M. A. Rosatti Filho, T. Oliveira Pires Companhia do Metropolitano de São Paulo - METRÔ, São Paulo, Brasil

1 - Introduction 11.5 km

NATM 2 TBM – EPB Ø 6,86 m 1 TBM – EPB Ø 10,58 m

SÃO PAULO LINE 5 – “LILÁS”

Chácara Klabin Dionísio da Costa

May-June 2016

Commercial Offices Building

2 - The Problem

Building footprint of different area Vertical stress (pressure bulb) overlap with the excavation tunnel section

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3 - Geological Setting

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Technogenic Soils (1)

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Technogenic Soils (1)

Clay (3Ag1)

São Paulo Formations

Fine Sand (3Ar1)

Coarse-Fine Sand (3Ar2)

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Technogenic Soils (1)

Clay (3Ag1)

São Paulo Formations

Fine Sand (3Ar1)

Coarse-Fine Sand (3Ar2)

Stiff Clay (4Ag1)

Resende Formations

Clayey Sand (4Ag2)

Coarse-Medium Sand (3Ar1)

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Technogenic Soils (1)

Clay (3Ag1)

São Paulo Formations

Fine Sand (3Ar1)

Coarse-Fine Sand (3Ar2)

Stiff Clay (4Ag1)

Resende Formations

Clayey Sand (4Ag2)

Coarse-Medium Sand (3Ar1)

Underground Water LevelFinal design

735

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3Ar 1

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Technogenic Soils (1)

Clay (3Ag1)

São Paulo Formations

Fine Sand (3Ar1)

Coarse-Fine Sand (3Ar2)

Stiff Clay (4Ag1)

Resende Formations

Clayey Sand (4Ag2)

Coarse-Medium Sand (3Ar1)

Underground Water LevelFinal design

Underground Water LevelMeasured by the piezometers at April-May 2016

Table 1. Main geotechnical characteristics of the soils, involved in the considered section. Geological Formations

Geotechnical Units

c' (kPa)

φ' (o)

γ (kN/m3)

Es (MPa)

K (cm/s)

São Paulo

Fine Medium Sand 10 32 19,00 40 5,0E-04

Clay 40 20 18,00 20 5,0E-06

Resende Stiff Clay 60 20 20,00 70 5,0E-07

Stiff Clayey Sand 60 22 20,00 70 5,0E-07

4a - Greenfield Settlement Analytical method of New and O’Reilly (1991)

It must be recognised that ground settlement, of itself, does not damage structures and is therefore likely to be an unreliable measure of damage potential. It is the differential ground movements which give rise to the angular distortion and horizontal ground scrains which cause damage. In particular it is the hogging curvature and tensile strain beneath structures which will be the best measures of the risk of damage. The maximum angular distortion (/3) for the overlying buildings is calculated based on the typical building length, B, and the maximum slope of the settlement profile beneath it. NB The angular distortion describes the rotation of a line joining two reference points on the structure relative to the rigid body tilt of the structure (See Figure 2). At a particular part of a structure it is equal to the slope of the settlement trough at that point relative to the building tilt. The angular distortion of any structure is also, of course, dependent on its location with respect to the tunnel. For a single tunnel the building will suffer the maximum angular distortions and tensile ground strain when centred a t a distance of about J 3 i U 3 Kz ) from the tunnel centre line . For twin tunne l s the position may vary considerably due to superposition of distortions and strains in the zone between the tunnels. The area of ground above the tunnel which is sub ject to significant ground movements is then identified. This may be taken as a strip of ground extending a distance of 2.5 i (2.5Kz) on either si~e of the tunnel centreline . (For twin tunnels this becomes D/2 + 2.5Kz on either side of the midpoint between the tunnels, see Fig 2).

considering the volume loss VL=0,5%, the trough width parameter constant K=0,4 (clay excavation), on the tunnel axis, the predicting magnitude of the settlement, resulting of 20mm, superficial and 47mm at 2m up the top heading (Figure 3)

Volume Loss VL=0,5%

Constant K=0,4 (clay excavation)

Transversal coordinate (m)0 10 20 30 40-10-20-30-40

0,0

1,0

2,0

3,0

4,0

5,0

Superficial Settlement

Settlement 2m up thetop heading

Max magnitude of the settlement: -   20mm (superficial)

Transversal coordinate (m)0 10 20 30 40-10-20-30-40

0,0

1,0

2,0

3,0

4,0

5,0

Superficial Settlement

Settlement 2m up thetop heading

Max magnitude of the settlement: -   20mm (superficial) -   47mm (2m up the top heading)

4b - Greenfield Settlement Analytical method of New and O’Reilly (1991)

It must be recognised that ground settlement, of itself, does not damage structures and is therefore likely to be an unreliable measure of damage potential. It is the differential ground movements which give rise to the angular distortion and horizontal ground scrains which cause damage. In particular it is the hogging curvature and tensile strain beneath structures which will be the best measures of the risk of damage. The maximum angular distortion (/3) for the overlying buildings is calculated based on the typical building length, B, and the maximum slope of the settlement profile beneath it. NB The angular distortion describes the rotation of a line joining two reference points on the structure relative to the rigid body tilt of the structure (See Figure 2). At a particular part of a structure it is equal to the slope of the settlement trough at that point relative to the building tilt. The angular distortion of any structure is also, of course, dependent on its location with respect to the tunnel. For a single tunnel the building will suffer the maximum angular distortions and tensile ground strain when centred a t a distance of about J 3 i U 3 Kz ) from the tunnel centre line . For twin tunne l s the position may vary considerably due to superposition of distortions and strains in the zone between the tunnels. The area of ground above the tunnel which is sub ject to significant ground movements is then identified. This may be taken as a strip of ground extending a distance of 2.5 i (2.5Kz) on either si~e of the tunnel centreline . (For twin tunnels this becomes D/2 + 2.5Kz on either side of the midpoint between the tunnels, see Fig 2).

Transversal coordinate (m)0 10 20 30 40-10-20-30-40

0,0

1,0

2,0

3,0

4,0

5,0

Superficial Settlement

Settlement 2m up thetop headingSettlement 11m up thetop heading(foundation level)

Max magnitude of the settlement: -   20mm (superficial) -   47mm (2m up the top heading) -   32mm (11m up the top heading)

Attention limits considered Vertical movement of the building (S) ≤ 15 mm Rotation (θ) ≤ 1/500 Deflection ratio (Δ/L) ≤ 1/900

4c - Greenfield Settlement

It must be recognised that ground settlement, of itself, does not damage structures and is therefore likely to be an unreliable measure of damage potential. It is the differential ground movements which give rise to the angular distortion and horizontal ground scrains which cause damage. In particular it is the hogging curvature and tensile strain beneath structures which will be the best measures of the risk of damage. The maximum angular distortion (/3) for the overlying buildings is calculated based on the typical building length, B, and the maximum slope of the settlement profile beneath it. NB The angular distortion describes the rotation of a line joining two reference points on the structure relative to the rigid body tilt of the structure (See Figure 2). At a particular part of a structure it is equal to the slope of the settlement trough at that point relative to the building tilt. The angular distortion of any structure is also, of course, dependent on its location with respect to the tunnel. For a single tunnel the building will suffer the maximum angular distortions and tensile ground strain when centred a t a distance of about J 3 i U 3 Kz ) from the tunnel centre line . For twin tunne l s the position may vary considerably due to superposition of distortions and strains in the zone between the tunnels. The area of ground above the tunnel which is sub ject to significant ground movements is then identified. This may be taken as a strip of ground extending a distance of 2.5 i (2.5Kz) on either si~e of the tunnel centreline . (For twin tunnels this becomes D/2 + 2.5Kz on either side of the midpoint between the tunnels, see Fig 2).

Transversal coordinate (m)0 10 20 30 40-10-20-30-40

0,0

1,0

2,0

3,0

4,0

5,0

Superficial Settlement

Settlement 2m up thetop headingSettlement 11m up thetop heading(foundation level)

Deformation Parameter of the Building

Calculated Max vertical movement of the building (S) = 32mm Max differential settlements (δS) = 25mm Max rotation (θ) = 1/526 Max relative deflection (Δ) = 22mm Max deflection ratio (Δ/L) = 1/909

Allarm limits considered Vertical movement of the building (S) ≤ 30 mm Rotation (θ) ≤ 1/250 Deflection ratio (Δ/L) ≤ 1/450

•   Superficial topographic marks •   Tassometers •   Inclinometers •   Piezometers

5 - Monitoring System

It must be recognised that ground settlement, of itself, does not damage structures and is therefore likely to be an unreliable measure of damage potential. It is the differential ground movements which give rise to the angular distortion and horizontal ground scrains which cause damage. In particular it is the hogging curvature and tensile strain beneath structures which will be the best measures of the risk of damage. The maximum angular distortion (/3) for the overlying buildings is calculated based on the typical building length, B, and the maximum slope of the settlement profile beneath it. NB The angular distortion describes the rotation of a line joining two reference points on the structure relative to the rigid body tilt of the structure (See Figure 2). At a particular part of a structure it is equal to the slope of the settlement trough at that point relative to the building tilt. The angular distortion of any structure is also, of course, dependent on its location with respect to the tunnel. For a single tunnel the building will suffer the maximum angular distortions and tensile ground strain when centred a t a distance of about J 3 i U 3 Kz ) from the tunnel centre line . For twin tunne l s the position may vary considerably due to superposition of distortions and strains in the zone between the tunnels. The area of ground above the tunnel which is sub ject to significant ground movements is then identified. This may be taken as a strip of ground extending a distance of 2.5 i (2.5Kz) on either si~e of the tunnel centreline . (For twin tunnels this becomes D/2 + 2.5Kz on either side of the midpoint between the tunnels, see Fig 2).

•   Superficial topographic marks •   Tassometers •   Inclinometers •   Piezometers •   Optical targets

Monitoring Building - 2nd Floor Underground (May, 2016)

Monitoring Building - 2nd Floor Underground (May, 2016) Frequency readings 2-8 measurements per day

6a - TBM Face Pressure Caquot-Karisel (1956) based on the plasticity theorems, integrated by Carranza- Torres

Stability model for ‘wet’ ground - dry tunnel

Stability model for ‘dry’ ground conditions

qs = 20kPa Fs = 2

6b - TBM Face Pressure

qs = 20kPa Fs = 2

Calculated in correspondence to the building:

•   202-220 kPa – PAT Executive Project

•   170 kPa – PAT improving for variation on the underground water level without footing pressure

contribution

Calculated in correspondence to the building:

•   202-220 kPa – PAT Executive Project

Calculated in correspondence to the building:

•   202-220 kPa – PAT Executive Project

•   170 kPa – PAT improving for variation on the underground water level without footing pressure

contribution

•   230 kPa – PAT improving for variation on the underground water level with footing pressure

contribution

7 - Building Foundation Vertical Stress Contribution

Steinbrenner Chart Based on theory of elasticity

Principal sizes footing = 32 m2

Applied load = 14.400 kN Up-pressure contribution = 60 kPa

Principal sizes footing = 32 m2

Applied load = 14.400 kN

8 - PAT Improving

Calculated in correspondence to the building:

•   170 kPa – PAT improving for variation on the underground water level without footing pressure

contribution

•   230 kPa – PAT improving for variation on the underground water level with footing pressure

contribution

The PAT Improving has been considered also a pondering on the deformation behavior of the ground

mass:

•   variation of the heading

•   lateral geological structuring

•   presence of others interferences in the area

•   application procedure for the grout injection to fill the voids between the extrados of the lining and

the excavated tunnel profile, at the tail shield

100,0

120,0

140,0

160,0

180,0

200,0

220,0

240,0

260,0

280,0

300,0

21170 21180 21190 21200 21210 21220 21230 21240 21250

Pres

sure

(kPa

)

Pk (m)

Referenced Face Pressures

Pressure S1 - PAT Improving

Pressure S1 - PAT Improving whitout building

Building Interference

Calculated in correspondence to the building:

•   170 kPa – PAT improving for variation on the underground water level without footing pressure

contribution

•   230 kPa – PAT improving for variation on the underground water level with footing pressure

contribution

9a - Results

During the excavation of the TBM the face pressures were maintained within the values indicated in the improving PAT

9b - Results

The weight ground’s mass value extracted from the screw conveyor of the TBM were maintained respect to the theoretical value as shown the ratio R (Ratio R, between the mass of the actually extracted material from the screw conveyor and the theoretical mass)

9c - Results

Regarding the TBM penetration rate, it can be seen that this parameter show constant values in the considered section

9d - Results

The deformation of the soil mass during the TBM excavation has been mild and negligible in relation to the foreseen limits; •   Max. 2-3mm (Optical Target buiding) •   Angular rotations of the building

practically nil

Metro Line 5 Lilas - TBMOptical Target - Building in Rua Fabio Prado 211

Metro Line 5 Lilas - TBMOptical Target - Building in Rua Fabio Prado 211

9e - Results

The deformation of the soil mass during the TBM excavation has been mild and negligible in relation to the foreseen limits; •   Max. 3,5mm (T-01, section EX

21+144)

Metro Line 5 Lilas - TBMChacara Klabin/Dionisio - Monitoring Section 21+144

Metro Line 5 Lilas - TBMChacara Klabin/Dionisio - Monitoring Section 21+199

Metro Line 5 Lilas - TBMChacara Klabin/Dionisio - Monitoring Section 21+230

10 - Conclusion The standard of the approach used for the PAT improving is shown by: i)  the continuous observance of the limits of recorded TBM parameters; ii)  the monitoring data results, with small vertical deformation of the foundations

building (2-3mm), without significant angular rotations; iii)  the absence of building damages and segment damages of the tunnel. The PAT improving was the result of a correct analysis approach of the boundary conditions to the tunnel, in particular taking into consideration the contribution of the: i)  up-load of the building at the TBM face pressure; ii)  its distribution along the section, defined with a pondering on the deformation

behavior related to the •   backfill grouting, •   variation to the heading, •   lateral geological structuring , •   presence of others interferences.

Moreover, the goodness of the work has been possible by the good involvement, collaboration and relationship between the Metro Supervision staff, the Metro Consultant (designer) and the Contractor TBM staff.

The standard of the approach used for the PAT improving is shown by: i)  the continuous observance of the limits of recorded TBM parameters; ii)  the monitoring data results, with small vertical deformation of the foundations

building (2-3mm), without significant angular rotations; iii)  the absence of building damages and segment damages of the tunnel. The PAT improving was the result of a correct analysis approach of the boundary conditions to the tunnel, in particular taking into consideration the contribution of the: i)  up-load of the building at the TBM face pressure; ii)  its distribution along the section, defined with a pondering on the deformation

behavior related to the •   backfill grouting, •   variation to the heading, •   lateral geological structuring , •   presence of others interferences.

Thank You! D. Agnella

GETAD Consult, São Paulo, Brasil

W. J. Giannotti, M. A. Rosatti Filho, T. Oliveira Pires Companhia do Metropolitano de São Paulo - METRÔ, São Paulo, Brasil

Tunnel Chácara Klabin – Dionísio da Costa (June, 2016) Breakthrough in Dionísio da Costa (June, 2016)