Experiences of Ground Improvement for Urban Tunnels in Difficult

Akira Koshima, Giorgio Guatteri -1-
Experiences of Ground Improvement for Urban Tunnels in
Difficult Conditions
Authors:
Akira Koshima -- technical manager, Novatecna Consolidações e Construções S/A and 2002-2006
president of the Brazilian Tunnelling Committee, ABMS, São Paulo, Brazil, [email protected]
Giorgio Guatteri -- CEO, Novatecna Consolidações e Construções S/A, and Terrajato, São Paulo,
Brazil, [email protected]
SUMMARY
A brief overview of jet grouting in Brazil is followed by “why and when” basics in relation to ground
improvement for safe tunnel excavating. A number of case histories are reported - mostly NATM tunnels
involving what were seen as difficult, new, or unusual situations. Our report is based on our own ground
improvement experience - over a million meters for 56 tunnels and 26 years of specialized geotechnical work in
Brazil, Portugal, Madeira, and Venezuela.
1.
JET GROUTING TECHNOLOGY IN BRAZIL
As far as Brazilian engineers are concerned, Guatteri [1] introduced jet grouting in the early 1980s, and it spread
to the rest of the Americas, north and south -- Argentina (1983), California (1983), and then other LatinAmerican countries (except Venezuela where it had already been used in 1979) [2] – followed by Iraq (1987)
and Taiwan (1993). In the 1990s, jet grouting was used for Lisbon’s subway modernization (Novatecna Portugal,
1994 - 1998), more recently Caracas subway (Novatecna Caracas, 2000 and ongoing), and there is a project
underway in Spain.
Japanese engineers have done development work on jet grouting since the 1970s. More specifically CCP
(Cement Churning Pile or single fluid ) is attributed to Nakanishi (1970); JSG or JG (Jumbo Special Grout or
Jumbo Grout or double fluid, air and cement slurry) to Yahiro (1970) (panel jet) and Yahiro and Nakanishi
(1975) (column); CJG (Column Jet Grout or triple fluid) to Yahiro et al (1976); SSS Man (Super Soil
Stabilization Management) to Nakanishi (1985); Cross Jet to Shibazaki et al (1996) and Superjet to Yoshida et al
(1996).
In Brazil, the CCP or single-fluid technique was initially used in the 1980s (Novatecna); JSG or JG double-fluid
method was introduced in 1985 (Novatecna); and horizontal jet grouting in 1987 (Novatecna & Rodio); in 1988
the Column Jet Grout (CJG, Embrajet), and 1989 Extended Nozzle Jet (ENJ, Novatecna) [3]. In 1998, Novatecna
was the first to use horizontal jet grouting for full excavation profile (360o) and front septum.
Novatecna played a leading role in developing the technology in Brazil, together with consultants, designers and
construction companies, and led the more innovative uses of jet grouting in tunnels, including some major
underground structures [3 - 33].
The basic jet grouting concept is driving a metallic rod (diameter 7-10 cm) into the ground mass and then
injecting soil and cement slurry under high pressure ( 800 to 1000 km/h nozzle speed) to break down soil into a
homogeneous soil-cement slurry hardening into a cylindrical format (diameter 0.4 to 2 m) from the hole.
Fig. 1 – View of jets
Fig .2 – Test Field
Akira Koshima, Giorgio Guatteri-- 2 –
The resulting consolidated mass is very strong and highly impermeable after curing. Since they depend on
drilling alone, columns may be restricted to the strictly necessary cross section, and may be positioned at any
angle from vertical to horizontal, and in any type of soil without restrictions in relation to granulometrics,
geological origin, or presence of water (figs. 1 and 2).
2. NEED FOR TREATMENT
2.1.
Arch effect
On excavating the tunnel, pre-existing ground mass stresses are channeled along its profile, so certain areas on
the walls of the excavation come under pressure. This channeling of stress along the cavity profile is referred to
as the “arch effect” and this phenomenon means that a cavity may be created in the ground. [39 - 40]
The extent of the “arch effect” will depend on the magnitude of pre-existing ground stresses and their strength
and deformability, which may be manifested in the following ways (fig. 3):
a) in the proximity of the excavation surface;
b) further away from the excavation surface;
c) it may not occur at all
EFEITO ARCO
EFEITO ARCO
3
1
2
NATURAL
2
DESVIADO
1
3
INEXISTENTE
Fig. 3 – Arch effect
The first case (a) occurs when ground mass is well able to support the flow of diverted stresses and responds in
the elastic field in terms of active tensions and deformations.
The second case (b) occurs when the solid responds by plastifying and deforming radially. Thus stress
canalization is diverted within the ground mass, until the triaxial state of tensions becomes compatible with
strength and deformation characteristics. In this situation the “arch effect” occurs far from the excavation walls
and disintegrated ground around the profile may contribute to the final statics with residual strength alone. Major
deformations, convergences, etc. may occur in this way.
The third case (c) occurs when the ground around the excavation profile is not capable of supporting the new
pattern of diverted stresses and responds at the failure stage, causing cavity collapse.
From these three cases, we see:
· The arch effect is produced as a natural consequence only in the first case. The ground is resistant and selfstanding, so no treatment is required.
· In the second case, the arch effect occurs as a natural consequence only if the ground is “helped” through
stabilizing interventions, or based on a major deformation. Treatment may be necessary in this case.
. In the third case, the arch effect does not occur as a natural consequence, and must be created “artificially” by
intervening in the ground prior to excavation. Treatment is required.
Akira Koshima, Giorgio Guatteri-- 3 –
2.2.
Intervention system
“Intervention systems” may be divided in two main groups: “Sustaining approach” (passive) and “confinement
approach” (active), (Lunardi, 1994). (fig. 4)
AÇÃO
INTERVENÇÃO
SUSTENTAÇÃO
ESCORAS DE MADEIRA
PASSIVO
EFEITO ARCO
PRÉ-SUSTENTAÇÃO
TUBOS EM PRÉ-FUROS E CAMBOTAS
CONTENÇÃO
(CONFINAMENTO)
CHUMBADORES RADIAIS E
CONCRETO PROJETADO
ATIVO
PRÉ-CONTENÇÃO
(PRÉ-CONFINAMENTO)
BARRAS DE FIBRA DE VIDRO
NA FRENTE DE AVANÇO
Fig. 4 – Intervention systems
Either approach may intervene after excavation (sustentation / contention) or prior to starting excavation (presustentation / pre-contention).
2.2.1. Sustaining approach (passive)
The “sustaining” approach assumes that even the use of structural elements supported on steel ribs along the arch
is not capable of creating an arch effect on an advance, due to the lack of reciprocal collaboration transversally,
as well as being based on a passive intervention concept.
Sustentation includes: timber props, steel ribs, etc;
Pre-sustentation includes tubes or short bars of any type, possibly placed in pre-drilled holes, which may be
filled with cement slurry and supported by steel ribs, such as driven metallic sheet forepoling, also known as
marciavante, extended reinforced low pressure injected forepoles for structural purposes.
2.2.2. Confinement approach (active)
. The interventionist or “confinement approach” is based on producing and controlling an arch effect
(transversally) in the ground, naturally or artificially. The active intervention concept emphasizes protection of
the excavation face, as theorized by Kastner in the 1950s and developed by Rabcewicz in the 1960s.
Confinement includes shotcreting, several types of radial bolts, different types of TBM shields (open face,
compressed air, slurry, EPB, etc.).
Pre-confinement includes ground treatments by injecting cement of different types and textures; chemical
injections; freezing; jet grouting; mechanical pre-cut; reinforcing core with fiberglass nailings / spilings or other
processes; cellular arch with jacked tubes or pipe-roof etc. (fig. 5, Lunardi, 1994)
INTERVENÇÃO
SOLOS
ARGILA
INJEÇÕES
CONVENCIONAIS
CONGELAMENTO
JET-GROUTING HORIZONTAL
PRÉ-TUNEL
REFORÇO DO NÚCLEO COM TUBOS
DE FIBRA DE VIDRO
PRÉ-CORTE MECÂNICO
ARCO CELULAR
Fig. 5 – Pre-confinement processes
SILTE
AREIA
CASCALHO
ROCHA
FRATURADA
ROCHA
Akira Koshima, Giorgio Guatteri-- 4 –
3. GROUND IMPROVEMENT EQUIPMENT AND ACCESSORIES
3.1. Drilling and injection rigs
Novatecna has designed and built new or modified existing drilling rigs for ground improvement based on the
needs experienced in each project. On this basis, we have worked with tunnel diameters ranging from 3.0m to
over 10m (floor-to-vault).
In the basic concept, the drilling-injection device, known as the positioner, is prepared for a 12m perforation
without maneuvering the rod and without needing a platform. The horizontal drilling and jetting positioner is
assembled with one or two telescopic hydraulic pistons as mast supports, with fully independent motion so as to
provide quick and accurate set up of the drilling string along the required direction (fig. 6). In addition to its
versatility for precise guidance and speed of positioning holes, a laser beam cannon is used to focus the design
with homothetic projections of the drill points located on the treatment face, with inclination and spacing as
designed. (fig. 7)
Fig. 6 – Modern horizontal drill rig (positioner)
Fig. 7– Drill guidance using template and laser beam
Pumped water for drilling and cleaning the hole, or cement slurry during the injection phase, flows through highpressure hoses driven by a pump (approx. 300 HP) located outside the tunnel. Coupled to the pump system is an
automated high-turbulence mixer-agitator system preparing and continuously loading 18,000 liters or more of
cement slurry per hour.
After positioning the machine, rotational drilling starts with water circulating and proceeds until a predetermined
drill-hole length is reached. This machine may be adapted for rotary-percussion drilling when working in ground
containing rock blocks, without altering the other sequences described below.
On withdrawing the drilling string, the injection phase starts immediately; ground mass is disintegrated by
kinetic action and the impact of the cement slurry jet originated by potential energy equivalent to 2000 - 4000
meters of water column. The slurry is thoroughly mixed with the disintegrated ground by rotating and
withdrawing the drilling string to form soil-cement columns. Note that these operations are fully automated.
Excess soil-cement mixture (reflux) has to be removed through the drill-hole itself.
For treatment around the tunnel profile and the front septum, the horizontal drilling and jetting positioner allows
a wider range of movements by means of specific gearing, so that the mast may rotate 360° in relation to the rig
and be set up in an advanced position to execute invert and septum columns. The positioner is also equipped
with two 360° rotational gears, one mounted on the frontal mast support and the second placed onto the vertical
axis of the crawler rig (fig. 8). Due to the versatility of this type of positioner, face teams often call it the
“Kamasutra.”
Fig. 8 – Horizontal drilling rig executing
HJG and front septum
Akira Koshima, Giorgio Guatteri-- 5 –
3.2. Accessory “preventer valve” for drilling and horizontal jet grouting
This oil engineering accessory is called a “preventer valve” (or “blow-up preventer”) and is used to avoid gas
leaks and explosions when drilling oil wells.
Preventer valves and retainers at the mouth of the hole control outflows of solid or liquid spoils from drilling
when ground is sandy and susceptible to “piping.” They also facilitate control of reflux (excess soil-cement
mixture) during jet horizontal grouting jobs, thus avoiding “piping” along the hole or the column. (figs. 9, 10)
Major tunnelling jobs using preventers:
Fig. 9 – Preventer valve schematic
Fig. 10 – Preventer valve view
- Tamanduateí Tunnel, in the city of São Paulo, Brazil. Excavated in coarse sandy-gravel ground to a depth of
25m under the Tamanduateí River with the top of its diaphragm walls around 5m from the tunnel roof. This was
the 1st use of preventer valves and 360o front septum treatment solution using horizontal jet grouting, in 1998.
- Copacabana Subway Tunnel, Rio de Janeiro, Brazil. Excavated in saturated beach sand and in silty sandy
micacious gneiss residual soil under a 7-storey building with direct foundations. The distance between the tunnel
roof and the foundation base was about 6m. Treatment was 360o and front septum using HJG (in 2000).
- Subway tunnel in Caracas, Venezuela. Excavated in sandy paleovale with gravel - solution similar to the
Copacabana tunnel, in 2002.
- Cidade Jardim Tunnel, São Paulo, Brazil. Very shallow traffic tunnel with 2 - 5m overburden and vault
excavated in saturated sandy alluvium with gravel. Pre-lining executed on the vault using horizontal jet grouting
reinforced with metallic piping and front septum, in 2004.
- São Paulo Subway Lines 2 and 4, Brazil.- Used on 9 sites where Novatecna is or was involved using preventer
sporadically.
4
CASE HISTORIES
4.1. Campinas traffic tunnel, São Paulo, Brazil
This was the 1st tunnel in Brazil (in 1987) to use horizontal jet grouting (HJG) with a diameter of 0.50m on
sections not accessible from the surface and also with Jumbo Grout columns (diameter 1.6m), when ground
treatment was possible from the surface. [12]
The tunnel cuts through Tubarão and Itararé formation sedimentary ground mass, which includes porous
colluviums, sand and sandy siltstone, with groundwater level above the tunnel vault. Since this was a large urban
tunnel (125m2), with shallow overburden (3 -15m) in unfavorable geological conditions, horizontal (HJG) and
jumbo grout (JG) methods were used, being entirely new solutions for tunnel engineering at that time.
Jet grouting (HJG) facilitated ground mass consolidation through the tunnel excavation face in sections under the
avenues, houses and the rail classification yard without affecting the surface.
This technique involves laying a consolidated arch of juxtaposed soil-cement columns prior to excavation, which
minimizes settlement and avoids soil loss, particularly in sandy, low-cohesion, low-strength soils immersed in
Akira Koshima, Giorgio Guatteri-- 6 –
groundwater. Due to the porous and low-strength supporting soil, the HJG solution for the vault was combined
with prior widening of the arch foot (elephant foot) using forward sloping CCP columns, thus reducing
settlement under the railroad. In addition, in order to confine the saturated siltstone ground mass for benching, jet
grouting columns were executed sloping from mid-cross-section and interlinked through a shotcrete shoe
projected over the arch support or elephant foot.
Another technique used was jumbo grout, with vertical side-by-side columns around the excavated section
(diameter 1.6m), executed from the surface when possible (certain limited areas such as the portal or sides of the
retaining wall) of trench excavations. This concept, with an arch formed by JG columns was used for the north
portals (railway classification yard) where tunnel width reached 18m due to the curved geometry of the
alignment, with only 3m overburden under the main railroad. A JG gravity wall was executed along the railroad
alignment as retention for 15m excavations. (figs. 11, 12)
Fig. 11 – Shallow rail tunnel portals (3.0m)
Fig. 12 – Jet grouting 15m high gravity wall
4.2. Copacabana subway tunnel, Rio de Janeiro, Brazil
Rio de Janeiro'
s subway company planned a 750m extension to line 1, from Cardinal Arcoverde Station to the
center of Copacabana, also building Siqueira Campos Station and turn-offs or maneuvering areas. The
underground structure comprised two independent but juxtaposed “eyeglass type” tunnels crossing gneissic rock,
saprolite and micacious residual silty-sandy soil and sandy clayish soil of marine origin, of high hydrogeological complexity; the route also crossed a densely populated built-up area. [27]
One of the greatest challenges was the NATM section of the tunnels under the direct foundations of a 50-yearold 7-storey building, standing on sandy sediment (beach sand), with around 6m overburden. These tunnels were
previously treated with horizontal jet grouting forming a closed 360o conical chamber with treatment throughout
the excavation cross section and front septums protecting each advance module. (figs. 13, 14)
The work was successfully concluded on time and the preventer valve was a crucial factor in ground treatment
with maximum settlement of 30mm.
Fig. 13 – Face treatment
Fig. 14 – Front septum excavated by horizontal
jet grouting
4.3. Ipiranga Station in 300 m2 cave in soil, São Paulo Subway, Brazil
Ipiranga Station, now fully excavated with civil engineering work in the final phase, is on a 3km extension of
São Paulo Subway Line 2 from Ana Rosa Station.
Akira Koshima, Giorgio Guatteri-- 7 –
The cave is all underground and is the largest São Paulo Subway has excavated in soil in a built-up urban area.
The cross section (some 300m 2) was excavated from a central shaft about 35m in depth.
The station tunnel (diameter 35m) was excavated in predominantly clayish-silty varved São Paulo Tertiary soil ,
interspersed with discontinuous layers of fine-to-medium slightly clayish sands with SPT ranging from 20 to 40,
and groundwater level around 3.0m from the surface.
The station tunnel overburden varies from 9 to 24m.
Excavation of the cave proceeded in 4 phases, initially executing 2 side-drifts with invert at the turnstile level,
excavation of the vault to the height of the top of the side-drift, excavation of a partial bench to the invert of the
side-drift, and finally final benching down to the final invert. (fig. 15, 16).
CCPH
PREGAGENS
1,40
CALOTA
PONTEIRAS c/ 2,0m
DHPV
DHPV
17,35m
1,40
EIXO S. DRIFT
DA ESTAÇÃO
DHPV
PFV
6,15m
EIXO S. DRIFT
PFV
0m
DHPV
,2
SD
1
1
=1
REBAIXO - AID
4
R
SD
1
EIXO DO TÚNEL
2
REBAIXO
1/2 SEÇÃO
3
23,30m
Fig. 15 – 300m² station cavern excavated
below two rail lines
Fig. 16 – Cavern cross section
Due to the dimension of the tunnel cross section all sequential cross sections were treated with horizontal jet
grouting columns in the weaker sandy and clayish layers and in the remainder with injected pipe-roofing, besides
nailing the face and executing deep horizontal drains.
With such a large vault, 2 positioners were used simultaneously to speed treatment work for this section.
For final benching in sandy soils, we also used the well points system under vacuum to reduce neutral pressure.
4.4. Tunnel under Av. Cidade Jardim - Av. Brig. Faria Lima, São Paulo, Brazil
The Cidade Jardim traffic complex comprises 2 tunnels, with 2 traffic lanes and a pedestrians walkway over
each; the route eliminates a chronic traffic jam at the intersection between Av. Cidade Jardim - Av. Brig. Faria
Lima and under Rua Dr. Mário Ferraz, with a total length of 1,657 m, of which 880m is tunneled. [33]
Execution was planned for 7 months in order to minimize disruption. The 528m tunnel (in the center-suburb
direction) was excavated through three shafts and the ramp at the suburb end, thus providing access for 7 points
of attack. The other tunnel (length 535m, direction suburb-to-center) was executed from two service tunnels
excavated sideways from intermediate points between the shafts from the 1st tunnel, providing access to 4
excavation faces. Due to the difficult geometry of the road complex, horizontal space restrictions and shallow
overburden, four very different types of cross section were used: typical, widened bay, double and triple.
The following ground mass features were intercepted by the deeper excavations: Crystalline bed, mixture of
micacious sandy-silt residual soil and weathered gneiss rock. The upper part of the bed was completely
weathered (saprolite); The Resende Tertiary formation, aka taguá, has two main facies: one clayish and one
sandy. These facies occur in the form of sub-horizontal layers, usually with well individualized and marked
contacts
In the portal areas and the section under Av. Brig. Faria Lima where the alluvium layer was present, soil
treatment was required. This method was frequently used in areas with shallow overburden, varying from 1.5m
to 6m (over the length of the tunnels). Closed chambers were executed with multidirectional composition of
horizontal and vertical jet grouting columns in materials such as gravel, sands and organic clays commonly
found in alluvium regions.
Particularly in shallow overburden sections such as the one under Av. Faria Lima, the double-line treatment
comprised horizontal jet grouting and the internal one was reinforced with 2.1/2” schedule 40 piping (HJG-CB).
The use of HJG or HJG-CB in permeable soils ensures that the excavation perimeter is protected, even if located
below groundwater level. However, the excavation face remained exposed to water filtration and washing, thus
Akira Koshima, Giorgio Guatteri-- 8 –
facilitating “piping” in sandy soil. Several septums were required with sufficient thickness and impermeability to
provide safe excavating in stable watertight chambers for the crossing under Av. Faria Lima. These septums
were executed in three ways:
· from the surface: in double walls of vertical or angled (Ø=0.8m) grouting columns.
· inside the cross section: in sections where execution from the surface was not possible. HJG columns were
juxtaposed inside the tunnel to form a septum in front of the section to be excavated.
· combined solution: part of the septum was executed by vertical and the rest by horizontal jet grouting.
The section under Avenida Faria Lima was divided in three sub-sections in terms of treatment, with different
executive characteristics. (figs 17, 18 and 19):
ELÉTR
TEL
ELÉTR
TEL.
GÁS
ÁGUA
ÁGUA
ELÉTR
CET TEL PLUVIAL
ELÉTR
CET
ESGOTO
GREIDE
SEPTO
VERTICAL
SEPTO
HORIZONTAL
129
CCPH-BC
CCPH-BC
CCPH-BC
130
CCPH-BC
CCPH-BC
MACIÇAMENTO
ARGILA RIJA (TAGUÁ)
(ESTACAS)
131
132
CCPH-BC (AUTO PERFURANTE)
Fig. 17 – Longitudinal section of ramp center
CCPH-BC
CCPH
AREIAS
MÉDIAS E
FINAS
DHP
DHP
AREIA
GROSSA E
CASCALHO
Fig. 18 – Double treatment
15
AV. FARIA LIMA
20
25
30
Figure 19 - Triple section
RAMO 300
TAGUÁ
10
RAMO 200
5
RAMO 100
0
35
40
Akira Koshima, Giorgio Guatteri-- 9 –
The C section, starting from the ramp center in “cut and cover”, comprises a “big block” of vertical jet grouting
columns (Ø = 0.8m) and was executed as a mass of consolidated soil, thus acting as a wall to counteract ground
mass thrust when excavating the portal and “cut and cover” sections. This section presented particular difficulty
due to the numerous interferences from large numbers of utilities in this underground area.
In section B, the tunnel has very shallow overburden and the design included vertical jet grouting columns
around the excavation profile.
This is the section under the two carriageways of Av. Faria Lima. Due to the low overburden and presence of
dynamic load, treatments were executed in HJG-CB and minimum lateral penetration of 1 meter in the taguá
ground. The combination of large cross section (119 m2) with the great thickness of sandy, permeable soil and
shallow overburden required double-layer treatment. The internal layer was executed with HJG-CB and the
outside with HJG (fig. 18). Deep horizontal drains were placed between these two layers to ensure absolute
safety for excavation.
The presence of thick sand and gravel in the bottom meter of the sandy alluvium layer was constant throughout
all treatments; due to the ascending grade of the tunnel, this difficulty gradually and significantly worsened; in
particular due to the presence of water associated with the high permeability of this layer (fig. 19). The initial
drives from the attack shaft met with gravel in the final meters of perforation of the upper columns and required
the preventer valve to ensure quality treatment. For the next drive, the “preventer” had to be used on every
column. Some columns were located entirely in the gravel layer and presented particular difficulty. Drilling in
gravel raised friction between rod and soil and forced operators to be very quick and skillful; it also blocked use
of the positioner'
s automatic HJG system. Friction significantly reduces the working life of rods and injector
devices. On occasion, lateral friction exceeded positioner torque or rod strength and they had to be left in the
ground. In these cases, repair columns were executed outside the unfinished columns.
Face impermeability was achieved by execution of vertical septums comprising two lines of juxtaposed jet
grouted columns (diameter 0.80 m). Using HCCP for executing the septum would require a large number of
columns and take a long time due to the great thickness of the sandy soil layer. Executing these septums meant
partially closing traffic lanes on the avenue early mornings and weekends. Positioning for these septums was
adjusted in order to provide an appropriate length for treatment drill holes around the tunnel and avoid deviations
due to interferences, and position them along the avenue lanes. HJG -CB around the profile was inset 0.5m in
these septums.
The large cross section meant that two positioners could act simultaneously for several drives on this section
(fig. 20). This required more coordination from support teams and extra effort from the instrumentation team,
since faster treatment has a bigger effect on ground mass and requires “online” monitoring. Positioners should
ideally work at opposite ends in these cases.
HJG and horizontal drains were used in residual soil sections when necessary. Holes drilled to execute treatment
often intercepted interfaces between weathered rock and soil to reach within a few centimeters of alluvium
interface. In these cases, HJG was reinforced by introducing schedule piping along the axis.
Another major innovation was the use of video to monitor work inside the tunnel. The monitor in the containeroffice showed progress on the job and any difficulties arising, so measures could be taken quickly, thus
benefiting overall progress and optimizing decision-taking. (fig. 21)
Fig. 20 – Double section tunnel treatment
with two horizontal drill rigs
Fig. 21 – Internal TV circuit to track progress below
Akira Koshima, Giorgio Guatteri-- 10 –
4.5. Consolidation of Tagus River Alluvium for the EPB shield under the Cais
do Sodré railway station in Lisbon, Portugal
The initial excavation region for the EPB shield (diameter 9.8m), the departure point for the shield (cut-andcover future Cais do Sodré subway station) had to be consolidated with jet grouting to sustain the shield that
would start excavating “Tagus River mud” and crossing under the century-old Cais do Sodré railway station
building. This was the first of a series of projects for Novatecna Portugal in Lisbon in 1994. [19]
It was feared that there might be an irreparable loss of control over the shield excavating the clayish alluvium
soil with sandy lenses, soft, very saturated, dark gray, known as “Tagus River mud “. The consequences could be
settlement under the station building.
Single-fluid jet grouting was executed from the surface with sloping holes, from the vertical to about 30o to
horizontal, to form a consolidated mass supported on the Myocene layer.
The length of the treatment across the projection of the railway station was 62m. (figs. 22, 23)
ESTAÇÃO FERROVIÁRIA
CAIS DO SODRÉ
ED. ANEXO
TAPUME
FUNDAÇÃO
SHIELD
ATERRO
ALUVIÃO DO
RIO TEJO
MIOCENIO
Fig. 22 – Typical jet grouted envelope section
Fig. 23 – Cut and cover shield starting
4.6. Other new uses
Certain projects are worthy of special mention for their innovative use of jet grouting:
4.6.1. Tunnel under Av. Sto. Amaro, center-suburb direction, with up to 2.0m
overburden, São Paulo, Brazil
Due to the shallow overburden and geology indicating the presence of clayish and organic waterlogged alluvium,
with sandy intercalations of very low strength, overlaying taguá (hard greenish gray clay), the solution designed
was concrete-filled jacked steel pipes (∅ =1.0m) around the tunnel vault starting from a trench in the central
divide between the carriageways on Avenida Santo Amaro. The pipes were jacked in both directions to cross the
two lanes (suburb-center and vice-versa). The geometry for the distribution of the pipes around the cross section
of the tunnel involved pipejacking as far as possible through a central trench, without necessarily reaching the
alluvium / taguá contact. This pipe roof was supplemented with HJG on the two excavation faces of the tunnel to
provide supplementary support for the pipe roof in the taguá soil. HJG columns were also executed to block and
seal space between pipes. Two supports were executed from inside the two faces, in the form of HJG arch
segments to sustain the tunnel vault pipe roof, as in the two partial septums at each end of the pipes supported on
taguá, in addition to HJG forepoling for the core [18]. (figs. 24, 25)
Akira Koshima, Giorgio Guatteri-- 11 –
Fig. 24 – Longitudinal section
Fig. 25 – Typical tunnel cross section,
steel pipes and HJG
4.6.2. Nailing subway tunnel face with fiberglass (length 28 m) in Lisbon, Portugal.
This was the first time fiberglass nailing was used with 3 tape reinforcement elements (rectangular-cross-section,
composed of fiberglass) attached to the outer face of triangular spacers, with concentric rigid PVC piping to
ensure seamless 28m lengths. These fiberglass tapes were delivered and stored in reels to be cut into 28m lengths
on-site. Nailing elements were placed using a process similar to the self-drill method, with low water/cement
factor (0.4) cement slurry containing liquefier and expansion additives. The special positioner used featured two
long 25m masts with 11m vertical reach for excavating the tunnel full-section [37, 38]. (figs. 26, 27)
Fig. 26 – Two mast horizontal driling rig with
11m range
Fig. 27 – 28 m fiberlass nailing
5. CONCLUDING POINTS
Brazil'
s major tunnel project of the early 1980s involved over 75 km of tunnels on the Steel Railroad from Minas
Gerais to Rio de Janeiro. The technology available for ground improvement for excavation purposes was noreturn valve (manchette) forepoling reinforced with schedule tube as described in several articles in the Annals
of the Underground Excavation Symposium, 1982 [42] and [43].
We would add that the last 20 years have seen major advances in ground improvement for tunnel excavation,
particularly in urban areas, with the introduction and evolution of jet grouting technology in Brazil and
worldwide. The extent of this development is clearly seen in the review of tunnelling experiences in São Paulo
compiled by Negro, Sozio and Ferreira in 1992 [44], when the use of jet grouting for ground improvement was
still incipient. Major road, subway, and sanitation tunnels in São Paulo materialized thereafter - with more than
56 tunnels totaling over one million linear meters in 26 years, reflecting the authors'experience.
What is unarguable is that for safe excavation in adverse geotechnical conditions, the jet grouting solution of
creating a pre-lining over the tunnel vault prior to excavation is one of the most recommendable techniques, and
one of high productivity and efficiency as a treatment method. Tunnelling on this basis is a planned and
industrialized activity.
The average time required to execute an HJC column varies from 60 to 75 minutes, which beats the average for
any other technique available in Brazil, with fine technical performance and increasingly less interference in the
excavation cycle when working from inside the tunnel. Obviously if treatment is executed in advance, from the
surface if possible, with vertical and/or sloping jet grouting, the treatment period does not extend the tunnel
execution schedule.
Akira Koshima, Giorgio Guatteri-- 12 –
Acknowledgements
On behalf of Novatecna S.A, the authors thank the tunnelling community in Brazil for support,
recognition, and encouragement in using and developing this technology. In countries where we have been
active, this has facilitated transfer to the international community of the best applications of jet grouting on the
same level as the best international companies.
In particular we owe gratitude and special recognition to Paolo Mosiici and to the late Victorio Doro
Altan who were decisive in the use of this technology for so many years at Novatecna.
REFERENCES
[1] Abramento, M.; Koshima, A; Zirlis, AC. – chapter 18, Reforço do Terreno; in Fundações: Teoria e Prática,
published by PINI-ABMS ABEF, various authors and editors, 2nd edition / August 1998
[2] (Perri, G. – La Tecnologia “CCP” em el Metrô de Caracas, 8th Panamerican Congress of Soil Mechanics and
Foundation Engineering (CPMSEF), Cartagena, Colombia, August 1987)
[3] Mosiici, P. – High Pressure Injection Columns; ABEF Research on Foundation Engineering, XII ICMSF,
1989.
[4] Construção São Paulo, nº 2013/2014/2015 – Técnica “CCP” de consolidação de solos por cimentação a jatos,
3 parts, September 1986
[5] Teixeira, A H; Guatteri, G; Doro Altan, V. – The CCP Jet Grouting Method for Soil Improvement; VIII
E.C.S.M.F.E, Helsinki, May 1983
[6] Guatteri, G.;Teixeira A H – The Use of CCP Jet Grouting Method for Soil Improvement in Tunnelling;
Tunnelling in Soft and Water Bearing Grounds – AFTES – Paris, 1985
[7] Guatteri, G; Teixeira, A H; Martins, A. - Solutions of Stability Problems in Tunnelling by the CCP Method;
International Congress on Large Underground Openings, ITA International Tunnelling Association, Firenze,
Italy, June 1986
[8] Guatteri G., Mosiici, P.; - O Uso do Jet Grouting em Obras Subterrâneas Urbanas, 1st SEFE, September 1985
[9] Guatteri, G.; Mosiici, P.; Doro Altan, V – Jet Grouted Cut-off Walls, Proceedings of REMR Workshop on
New Remedial Seepage Control Methods for Embankment – Dams and Soil Foundations – U S Army Corps of
Engineers, Vicksburg, Mississipi, January 1988
[10] Teixeira, AH, Guatteri, G – Improvement of Soft Clays by Jet Grouting Technology, 8th CPMEF,
Cartagena, Colombia, August 1987
[11] Guatteri, G.; Kauschinger, J.L.; Doria, A C.; Perry, E.B. – Advances in the Construction and Design of Jet
Grouting Methods in South America; Second Internacional Conference on Case Histories in Geotechnical
Engineering, Missouri, St. Louis, June 1988.
[12] Dugnani, G; Guatteri, G.; Roberti, P; Mosiici, P. – Subhorizontal Jet Grouting Applied to a Large Urban
Twin tunnel in Campinas, Brazil, 12th International Conference on Soil Mechanics and Foundation Engineering
(ICMSF), vol 2, Rio Janeiro, October 1989
[13] Mosiici, P. – Jet Grouting Quality Control; Grouting in the Ground; Conference Proceedings, Institution of
Civil Engineers (PCICE), November 1992 and Annals published by Thomas Telford in 1994.
[14] Guatteri, G.; Mosiici, P.; Koshima, A ; Doro Altan, V. – Application of Jet Grouting to Tunnel Portals and
Top Headings in NATM Tunnelling: the Brazilian Experience; PCICE, November 1992 and Annals published
by Thomas Telford in 1994.
[15]Guatteri, G.; Mosiici, P.; Koshima, A - Túneis em Solos Tratados com Jet Grouting; 3rd Brazilian
Underground Escavation Symposium, Brasilia, August 1994
[16]Guatteri, G; Mosiici, P.; Koshima, A; Postiglione, P; Costa da Silva, A F. – Jet Grouting Horizontal no
Túnel Travessia sob o Rio Tietê; 3rd Brazilian Underground Escavation Symposium, Brasília, August 1994.
[17] Guatteri, G; Mosiici, P.; Koshima, A; Postiglione, - Enfilagem de Bulbo Contínuo no Tratamento de Túneis
do Mini Anel Viário; 10th Brazilian Soil Mechanics and Foundation Engineering Congress (X COBRAMSEG),
November 1994
[18] Guatteri, G; Mosiici, P.; Koshima, A; Harada, T.; Sozio, L.E. – Jet Grouting and Pipe Jacking in a Shallow
Urban Tunnel Construction; IS Tokyo´96, 2nd International Conference on Ground Improvement Geosystems,
Grouting and Deep Mixing, May 1996
[19] Doro Altan, V.; Mosiici, P – Jet Grouting Allows Passage of a 9.8 Shield Under a Building in Lisbon; IS
Tokyo´96, Grouting and Deep Mixing, May 1996.
[20] Postiglione, P.; Abrantes, J R C; Pinto, F; Mosiici, P.; Doro Altan, V; Consolidamentos com Jet Grouting na
Estação Poente do Complexo “Estações Baixa-Chiado” do Metropolitano de Lisboa; 6th National Geotechnics
Congress; Lisbon, Portugal, September 1997
[21] Guatteri, G; Mosiici, P.; Koshima, A; Doro Altan, V – Case History Related to a Jet Grouting Tunnels PreConsolidation With Minimun Coverage of 0.7m to 1.0 m – Under 345 Kv Cables and 8 Rapid Transit Road
Railway Lanes; International Tunnelling Congress, ITA, Prague, Czechoslovakia, October 1997
Akira Koshima, Giorgio Guatteri-- 13 –
[22] Guatteri, G; Mosiici, P.; Doro Altan, V.; Koshima, A – Brazilian Experience of Jet Grouting Treatment in
Difficult Tunnels; World Tunnel Congress 98, ITA CBT, Tunnels and Metropolises, São Paulo, April 1998.
[23] Guatteri, G; Doro Altan, V. – Jet Grouting Horizontal Permite Escavar Túnel sob Residência com Valioso
Painel Cerâmico; Tunnelling Seminar ( IST), Lisbon, Portugal, June 1998
[24] Guatteri, G; Koshima, A; Doro Altan V. – Enfilajes de Bulbo Continuo em Tuneles Excavados em Macizos
Terrosos Vs Enfilajes Tradicionales de Tubos a Manchettes, XI CPMSEF, Foz Iguaçu, Brazil, August 1999
[25] Guatteri,G; P.; Koshima, A.; Lopes, J ; Doro Altan V. – 360º Jet Grouted Conical Chamber Allows Safe
Tunnelling Under River Within a Highly Pervious Enviroment; Geoenge 2000 – An International Conference on
Geotechnical & Geological Engineering; Melbourne, Australia, November 2000
[26] Guatteri, G, Koshima, A.; Lopes J R; Pieroni, M R – Jet Grouting Horizontal em 360º e Septo em Túnel em
Areia sob o Rio Tamanduateí, 4th Urban Tunnel Symposium (4º TURB) , São Paulo, June 2002
[27] Guatteri, G; Lopes J R; Primo C R N P ; Brautigam, V.M.; Sózio, L.E; Koshima, A de Mello, L,G. – A
Construção de Dois Túneis do Metrô RJ sob o Edifício de 7 Andares em Copacabana. um Desafio a Engenharia
de Túneis, XII COBRAMSEG, 1st Luso-Brazilian Geotechnics Congress (1 CLBG), São Paulo, October 2002
[28] ] Guatteri, G; Martinati, R.; Moreira , L.A S; Koshima, A; Motidome, M- Concepção e Execução dos
Tratamentos do Túnel 3/4 , Emboque Santos da Nova Pista Rodovia Imigrantes, XII COBRAMSEG , I CLBG,
S.Paulo, October 2002
[29] Guatteri, G; Lopes J R; Koshima A; Guaraná, C A – A Aplicação de Técnica Inovadora na Execução de
Túnel Muito Raso sob a Rodovia Presidente Dutra; 1st Brazilian Tunnelling Congress (1º CBT/SAT 2004),
March 2004
[30] Guatteri, G; Koshima, A; Matsui, M; Andrade Junior, J C O, Pieroni, M R; Modesto Junior, C – A
Viabilização do Empreendimento com Uso do Jet Grouting Metrô Vila Madalena São Paulo; 1CBT/SAT 2004,
March 2004
[31] Guatteri, G; Koshima, A; Pieroni, M.R.; Moreira, L.A.S.; Lopes, J.R. – Jet Grouting Horizontal como
Condicionamento do Maciço para Escavação do Túnel Após Ruptura; 1º CBT , São Paulo, March 2004
[32] Guatteri, G; Koshima, A; Ravaglia,A, Duarte,M.. – Soluções em Jet Grouting para a linha 4 do Metrô
Caracas – Desafios em Obras Urbanas, XIII COBRAM SEG/III CLBG, Curitiba, August 2006
[33] Guatteri, G; Koshima, A; Pieroni, M.R.; Murakami, C.; Lopes, J.R. – A viabilização do Túnel Raso em
Aluvião Saturado Arenoso com Cascalho, em Jet Grouting – Túnel Travesia da Av. Cidade Jardim sob a Faria
Lima em São Paulo, XIII COBRAM SEG/III CLBG, Curitiba, August 2006
[34]Cruz, H J V; Couto, JVS; Hori, K; Salvoni,J. L; Ferrari, O A; Os Túneis do Prolongamento Norte – Uma
Primeira Avaliação do NATM em Área Urbana; Anais do Simpósio sobre Escavações Subterrâneas (Annals of
Underground Excavation Simposium), Vol. 1, RJ, November 1982
[35] Martinati, R – Aspectos Construtivos e Geotécnicos Relativos e Construção de um Túnel de 5,4 km de
Extensão Escavado ao Longo da Bacia Sedimentar de São Paulo; 3rd Urban Tunnel Symposium, October 1999
[36] Camara, F H; Debelin, P O; Gama E Silva R L – Urban Enviromental and Traffic Problems and The
Underground Solution; North Americam Tunnelling’ 96, ITA, Washington, USA, Abril 1996.
[37]Rocha, H C; Hori, K – Aspectos Construtivos dos Túneis do Metrô Paulista nos Sedimentos da Bacia de São
Paulo; 9th Brazilian Geology Congress, São Pedro, SP, November 1999
[38] Sózio, L E – Jet Setting in Rio; Tunnels & Tunnelling International, Abril 2002
[39] Lunardi, P. – Projeto e Construção de Túneis Segundo o Método Baseado nas Análises das Deformações
Controladas nas Rochas e nos Solos; Article translated by Pucci, M. and Mosiici, P., Published by ABMS in
1995.
[40] Lunardi, P. – Projeto e Construção de Túneis Segundo o Método Baseado nas Análises das Deformações
Controladas nas Rochas e nos Solos; part 2; Article translated by Pucci, M. and Mosiici, P., Published by ABMS
in 1995.
[41] Maffei, C.E.M.; Gonçalves H.H.S.; Guazzelli,M.C. – Uma Utilização Pioneira de Jet Grouting como
Escoramento, XI COBRAMSEG, Brasília, November 1998
[42] Anais do Simpósio Sobre Escavações Subterrâneas, various authors, Vol I E II, November 1982
[43]Carneiro, B P; Elias Filho, A; Campos, C.B ; Pinto, F A A; Carvalho, S A; Dias, J M V; Abijaodi R C;
Schettino, J N F – Experiências Práticas Obtidas no Avanço de Túneis sob Condições Especiais, Simpósio sobre
Escavações Subterrâneas , Volume 1 , November 1982
[44]Negro Jr, A; Sozio, L.E. ; Ferreira A. A . - Túneis; Solos da Cidade de São Paulo, Published by
ABMS/NRSP May 1992.