8/9/2019 1 Excavation Methods and Support System
1/55
3.1 Introduction3.2 Excavation Methods
3.3 Retaining Walls
3.4 Strutting Systems
3.5 Selection of the
Retaining Strut System
3.6 Case History of the
TNEC Excavation
Excavation Methods and Lateral SupportingSystems
3.2.1 Full Open Cut Methods3.2.2 Braced Excavation Methods3.2.3 Anchored Excavation Methods3.2.4 Island Excavation Methods3.2.5 Top-down Construction Methods
3.2.6 Zoned Excavation Methods
3.3.1 Soldier Piles3.3.2 Sheet Piles3.3.3 Column Piles3.3.4 Diaphragm Walls
8/9/2019 1 Excavation Methods and Support System
2/55
Definition of deep excavation
Terzaghi(1943)Whose excavation depths were larger thantheir widths
Terzaghi and Peck (1967) Peck et al.(1977)Whose depths were deeper than 6 meters
Introduction (in chapter 1)
8/9/2019 1 Excavation Methods and Support System
3/55
A complete deep excavation design
includes a retaining system, a strutting
system, a dewatering system, excavation
procedure, a monitoring system, building
protection , etc. Figure 1.1 illustrates the
general course of deep excavation design.
8/9/2019 1 Excavation Methods and Support System
4/55
Adjacent propertyinvestigation
Set the criteria fo r design
Confirm the conditions of
the excavation site
Decide excavationmethod
Decide auxiliary method
Decide depth of retainingwall
Whether economic ?
Strut design
Determination of theexcavation procedure
Deformation analysis
Meet the designcriteria ?
Stress analysis
Geologicalinvestigation
Boiling analysis
Push - in fa il ur eanalysis
Basal heaveanalysis
Detailed design of theretaining strutting system
Arrangement of monitoringsystems
Dewatering analysis
Uplift analysis
FIGURE 1 . 1 Flow chart for analysis and design of an excavation
Yes
Start
End
No
No
8/9/2019 1 Excavation Methods and Support System
5/55
Flow chart for analysis anddesign of an excavation
Adjacent propertyinvestigation
Set the criteria for design
Confirm the conditions ofthe excavation site
Decide excavationmethod
Decide auxiliary method
Decide depth of retainingwall
Whether economic?
Geologicalinvestigation
Boiling analysis
Push-in failureanalysis
Basal heaveanalysis
Yes
Start
No
No
8/9/2019 1 Excavation Methods and Support System
6/55
Strut design
Determination of the
excavation procedure
Deformation analysis
Meet the design
criteria?
Stress analysis
Detailed design of theretaining strutting system
Arrangement of monitoringsystems
Yes
End
No
Dewatering analysis
Uplift analysis
8/9/2019 1 Excavation Methods and Support System
7/55
3.2 Excavation Methods
3.2.1 Full Open Cut Methods
FIGURE 3.1 Sloped open cut method
a
8/9/2019 1 Excavation Methods and Support System
8/55
Retaining wall
3.2 Excavation Methods3.2.1 Full Open Cut Methods
FIGURE 3.2 Cantilevered open cut method
8/9/2019 1 Excavation Methods and Support System
9/55
3.2.2 Braced Excavation Methods
Excavation surface
BracketWale
Strut
Mat
Slab
Center post
Retaining wall
FIGURE 3.3 Braced excavation method (a) profile
8/9/2019 1 Excavation Methods and Support System
10/55
Retaining wallHorizontal strut
Brace
Wale
3.2.2 Braced Excavation Methods
FIGURE 3.3 Braced excavation method (b) plan
8/9/2019 1 Excavation Methods and Support System
11/55
3.2.2 Braced Excavation MethodsFigure 3.4
8/9/2019 1 Excavation Methods and Support System
12/55
3.2.3 Anchored Excavation Methods
Retaining wall
Anchor head
Anchor seat
Tendon
FIGURE 3.6 Basic configuration of an anchor
8/9/2019 1 Excavation Methods and Support System
13/55
Slab
Excavation surface
Anchor head
Free sectionAnchorage section
Mat foundation
3.2 Excavation Methods3.2.3 Anchored Excavation Methods
FIGURE 3.7 Profile of the anchored excavation method
8/9/2019 1 Excavation Methods and Support System
14/55
3.2.3 Anchored Excavation Methods
8/9/2019 1 Excavation Methods and Support System
15/55
Water flow
FIGURE 3.8 Problem of the anchored excavation method when applied inthe cohesionless soil with high groundwater level
Retaining wall
3.2.3 Anchored Excavation Methods
8/9/2019 1 Excavation Methods and Support System
16/55
3.2.4 Island Excavation Methods
q
o35q
Retaining wall
Raker Wale
FIGURE 3.9 Island excavation method with single level of struts
8/9/2019 1 Excavation Methods and Support System
17/55
3.2.4 Island Excavation Methods
FIGURE 3.10 Island excavation method with multiple levels of struts
Main structure
Center post
Wale
Retaining wall
Raker
8/9/2019 1 Excavation Methods and Support System
18/55
8/9/2019 1 Excavation Methods and Support System
19/55
3.2.5 Top-down Construction Methods
FIGURE 3.12 Top down construction method
Bearing stratum
Pile
Steel columnRetaining wall
Excavation surface
Excavation surface
Final excavation surfac
Floor slab
8/9/2019 1 Excavation Methods and Support System
20/55
3.2.6 Zoned Excavation Methods
Diaphragm wall
Wall deformation
FIGURE 3.13 Plan of an excavation
8/9/2019 1 Excavation Methods and Support System
21/55
A zone B zone
Diaphragm walla b
3.2.6 Zoned Excavation Methods
FIGURE 3.14 Plan of the zoned excavation method
8/9/2019 1 Excavation Methods and Support System
22/55
3.3 Retaining Walls
3.3.1 Soldier Piles3.3.2 Sheet Piles
3.3.3 Column Piles3.3.4 Diaphragm Walls
8/9/2019 1 Excavation Methods and Support System
23/55
3.3.1 Soldier Piles
WedgeSoldier pile
Lagging
(b)(a)
Backfill
FIGURE 3.15 Soldier piles (a) front view (b) section view
8/9/2019 1 Excavation Methods and Support System
24/55
3.3.1 Soldier Piles
h l
8/9/2019 1 Excavation Methods and Support System
25/55
3.3.2 Sheet Piles
Excavation bottom
FIGURE 3.17 Steel sheet pile method
8/9/2019 1 Excavation Methods and Support System
26/55
3.3.2 Sheet Piles3.3 Retaining Walls
3 3 2 Sh Pil
8/9/2019 1 Excavation Methods and Support System
27/55
( a )
( b )
( c )
3.3.2 Sheet Piles
FIGURE 3.19 Sections of steel sheet piles (a) U pile (b) Z pile (c) straight pile
8/9/2019 1 Excavation Methods and Support System
28/55
3.3.3 Column Piles
(1) Packed In Place pile. The diameter of PIP pile isaround 30 cm to 60 cm.
..
.
..
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
..
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.... .
. ..
..
..
.
..
.
.. .
. .
..
FIGURE 3.21 Construction procedure of a packed in place (PIP) pile
...
...
.
. .
....
.
.
.
. .. .
.
.
..
...
. .. .
.
..
.
.
3.3 Retaining Walls
3 3 3 C l Pil
8/9/2019 1 Excavation Methods and Support System
29/55
(2) Concrete piles
Reverse circulation drill method--
All casing method--
The diameters are around 60 cm to 200 cm.
3.3.3 Column Piles
3 3 3 C l Pil
8/9/2019 1 Excavation Methods and Support System
30/55
(3) Mixed piles.They are also called MIP piles (Mixed In
Place piles). The diameters are around 30 cm to 60 cm.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. .
.
.
.
.
.
.
.
.
.
.
. . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
(a) swirl the drillingrod and inject mortarinto the soil from the
bottom of thedrilling rod
(b) drill to thedesigned depth andtreat the soilsimultaneously whilekeeping swirling
(d) finish theimprovement
(c) withdraw thedrilling rod andinject the mortar simultaneously
FIGURE 3.22 Construction procedure of a mixed in place (MIP) pile
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
. . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. .
.
.
.
.
.
.
.
.
.
.
. . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
. . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
3.3.3 Column Piles
8/9/2019 1 Excavation Methods and Support System
31/55
SMW is a typical MIP piles.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
........
.
.. .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
..
.
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. ..
.
.
.
. ..
.
.
.
... .
...
.
. . ...
.
...
.
. .
....
...
.
.
.
.
.
...
.
.
.
. ..
.
..
.....
.
.
.
.
.
... .
...
.
.
.
.....
.... ..
.
.
.
...
....
.
.
.
.
.
...
....
.
.
..
. ..
.
.
.
.
... .. ..
.
.
.
.
FIGURE 3.23 Soil mixed wall (SMW)
8/9/2019 1 Excavation Methods and Support System
32/55
Layouts of column piles
( a )
( b )
15
24
79
68
3
1 683524 79
32 68 71 954
1 365
2 47
( c )
( d )
( e )
FIGURE 3.24 Layouts of column piles (a) independent pattern (b) S pattern
(c) line pattern (d) overlapping pattern (e) mixed pattern
3 3 4 Diaphragm Walls
8/9/2019 1 Excavation Methods and Support System
33/55
(a) (b) (d)
Groundwater
(c)
FIGURE 3.26 Construction procedure of a diaphragm wall panel(a) construction of the guided wall(b) excavation of the trench
(c) placement of reinforcements(d) concrete casting
3.3.4 Diaphragm Walls
Panel partition
8/9/2019 1 Excavation Methods and Support System
34/55
Panel partition----
Primary panelSecondary panel
8/9/2019 1 Excavation Methods and Support System
35/55
Guided wall construction----
8/9/2019 1 Excavation Methods and Support System
36/55
Trench excavation----
Clamp type----
8/9/2019 1 Excavation Methods and Support System
37/55
31 2
1 3 2
Hydraulic bucket
FIGURE 3.25 Trench excavation by the MHL method
8/9/2019 1 Excavation Methods and Support System
38/55
Rotatory type----
8/9/2019 1 Excavation Methods and Support System
39/55
Placement of reinforcements----
8/9/2019 1 Excavation Methods and Support System
40/55
The joint of diaphragm walls:
Connection pipe method--
End-plate method--
Stable waterConcreteGround Steel pipe
8/9/2019 1 Excavation Methods and Support System
41/55
( a ) ( b )
( c ) ( d )
FIGURE 3.27 Procedure of construction of a diaphragm wall (a) trenchexcavation (b) steel pipe installation (c) steel cage
placement (d) concrete casting
Stabilizer
surfaceConcrete surface
p p(connection pipe)
Tremie concreteStabilizer
Reinforcement cage
Fresh concrete
8/9/2019 1 Excavation Methods and Support System
42/55
Concrete
Connection pipe
FIGURE 3.29 Joint of diaphragm walls: theconnection pipe method
1. excavate trench
2. Place reinforcement cage and insert connection pipe
3. Backfill concrete and pull out connection pipe
4. Excavate secondary unitPrimary unit Secondary unit
Connection pipe method--
8/9/2019 1 Excavation Methods and Support System
43/55
End-plate method--
Angle steel forstopping water
Partition plate
Angle steel for stoping water
#10#5@30
40 50 20
6 0
Vinylon sheet
6-#8#5@60
#5@30#10
Tremie pipe
Short reinforced bar for fixing steel plate#4@60
FIGURE 3.30 Joint of diaphragm walls: the end-plate method (unit: cm)
8/9/2019 1 Excavation Methods and Support System
44/55
3.4 Strutting Systems
According to the material a strut is made of, thereare wood strut, RC strut, and steel strut.
According to the function of a strut, it is classifiedas an earth berm, a horizontal strut, a raker, ananchor, or as a top-down floor slab.
8/9/2019 1 Excavation Methods and Support System
45/55
Berm
Retaining wall
FIGURE 3.31 Earth berm as lateral support
R k
8/9/2019 1 Excavation Methods and Support System
46/55
Main structure
Steel pile
Retaining wall
Retaining wall
Raker
Raker
FIGURE 3.32 Rakers
8/9/2019 1 Excavation Methods and Support System
47/55
3.5 Selection of the Retaining Strut System
: good : acceptable : not good Note (1): should be applied along with special drill and striking device.
(2): if driven into soil by static vibrating, noise and vibration can be reduced.
TABLE 3.1 Application conditions for retaining walls
Wall type Soil type Sealing &Stiffness
Construction Conditions
BudgetSoftclay
SandGravel
soilSealing Stiffness
Noise &Vibration
Treatmentof dump
mud
Surfacesettlement
Soldier pile (1) (2)
Steel sheet pile
(2)
PIP pile
Reinforcedconcretecolumn
pile
MIP pile
Diaphragmwall
E x c a v a t
i o n
D e p
t h
U n
d e r g r o u n
d
O b s t r u c t
i o n
C o n s t r u c t
i o n p e r
i o d
8/9/2019 1 Excavation Methods and Support System
48/55
Retaining wall E (kg/cm 2)
I (cm 4/ m)
E I (t-m 2/ m)
StiffnessratioMethod Type & Dimension
Soldier
pile (1)H300x300x10x15 2.04 106 20,400 4,160 1.0
H350x350x12x19 2.04 106 40,300 8,220 2.0
Steel sheet
pile (2)SP- 2.04 106 16,400 3,350 0.8
SP- 2.04 106 31,900 6,500 1.6
Column
pile (3)30 cm (diameter) 2.1 105 132,500 2,780 0.7
80 cm (diameter) 2.1 105 2,513,300 52,780 12.7
Mip pile (4)SMW method
H400x200x8x132.04 106 59,250 12,090 2.9
Diaphragm
wall (5)50cm thick 2.1 105 1,041,700 21,900 5.3
100cm thick 2.1 105 8,333,300 175,000 42.0
TABLE 3.2 Nominal stiffness (before reduction)
8/9/2019 1 Excavation Methods and Support System
49/55
3.6 Case History of the TNEC ExcavationStreet
Inclinometer Extensometer Tiltmeter Main observation sectionPizometer Rebar stress meter Heave gaugeEarth/water pressure cell
FIGURE 3.33 Excavation of the Taipei National Enterprise Center (a) plan (b) profile
(a)
Scale0 5 10 m
F
E
DC
A
B
P R
Q S
8/9/2019 1 Excavation Methods and Support System
50/55
(b)
densegravel
N>100
compactto densesilty sand
N>14~37
stiff silty clay; N=9~11medium loose silty sand ; N=22~24
soft tomediumsilty clay
N=2~5
loose silty sand N=4~11
soft siltyclay
N=2~4
D e p t h
( m )
5
0
10
20
15
25
30
35
40
45
50
Diaphragm wall
Inclinometer Extensometer Heave gauge
Settlement mark Pizometer Earth/Piezometer cell
FIGURE 3.33 Excavation of the Taipei National Enterprise Center(a) plan (b) profile
8/9/2019 1 Excavation Methods and Support System
51/55
Pile
Steelcolumn
Diaphragm wall
(a) (b)
B1F
GL-19.7m
Strut
GL-19.7m
GL-4.9m
GL-2.8m
GL-35m
FIGURE 3.34 Construction procedure of the Taipei National Enterprise Center
(see Table 3.3 for the description of the construction procedure)
8/9/2019 1 Excavation Methods and Support System
52/55
(c)
B3FB2FB1F1F
6F
GL-19.7mGL-11.7m
GL-8.6m
(d)
GL-19.7m
GL-15.2mGL-17.3m
B4FB3FB2FB1F1F
Strut
FIGURE 3.34 Construction procedure of the Taipei National Enterprise Center(see Table 3.3 for the description of the construction procedure)
8/9/2019 1 Excavation Methods and Support System
53/55
TABLE 3.3 Excavation process of TNEC
8/9/2019 1 Excavation Methods and Support System
54/55
Stage Day Excavation activities
-29~ Installed devices outside of the excavation zone, including in-soilinclinometers, extensometers, observation wells, and electronic
piezometers1~89 Constructed the diaphragm wall, including installation of the earth/water
pressure cells, in-wall rebar strain meters, and in-wall inclinometers
89~147 Constructed piles and the steel columns
147~155 Installed devices inside of the excavation zone, including the piezometers
and heave gauges1 156~162 Excavated to the depth of GL-2.80 m
2 164~169 Installed struts H 3003001015 at the depth of GL-2.0 m. The preload ofeach strut 784.8 kN
3 181~188 Excavated to the depth of GL-4.9 m
4A 217 Constructed B1F floor slab at the depth of GL-3.5 m4B 222~238 Dismantled the first level of strut and constructed the 1F floor slab.
Started the construction of the superstructure
5 233~255 Excavated to the depth of GL-8.6 m
6 279 Constructed the B2F floor slab at the depth of GL-7.1 m
7 318~337 Excavated to the depth of GL-11.8 m
p
8/9/2019 1 Excavation Methods and Support System
55/55
Note The first day of the construction of the diaphragm wall is the datum
8 352 Constructed the B3F floor slab at the depth of GL-10.3 m
9 363~378 Excavated to the depth of GL-15.2 m
10 400 Constructed the B4F floor slab at the depth of GL-13.7 m11A 419~423 Excavated the central zone to the depth of GL-17.3 m
12A 425~429 Installed struts H4004001321 at the depth of GL-16.5 m in the centralzone. The preload of each strut 1177 kN
11B 430~436 Excavated the side zones to the depth of GL-17.3 m
12B 437~444 Installed struts H4004001321 in the two side zones at the depth ofGL-16.5 m. The preload of each strut 1177 kN
13 445~460 Excavated to the depth of GL-19.7 m
457 Finished the superstructure
14 464~468 Cast the foundation slab
15 506~520 Constructed the B5F floor slab at the depth of GL-17.1 m
16 528 Dismantled the second level of struts
Top Related