Drained and water tight tunnels

7/25/2019 Drained and water tight tunnels

1/20

Drained and Water

Tight Tunnel


2/20

Contents

2

Introduction

Infow in the construction phase

Groundwater Control during

Construction

Sealed Tunnel/Permanent Lining

Drained tunnel

Sealing (Waterproong o! Tunnel a"o#e

Ground Water Ta"le

Geos$nthetics %sed in Tunnels

Smart Drains


3/20

Introduction

3

Tunnels are always encountered with theseepage of water from the surrounding soil

or rock

below the ground water table

percolating water

groundwater and other waters must be

withdrawn from the tunnel Ground water must not inter into the tunnel

specially road and railway tunnels during its

service life


4/20

Infow in the construction phase

4

Heading inows occur whentunneling inters a water-bearing

one cases with ow rate more than

!"### $%s are reported appropriate resources &pumps

etc'( must be available on site

during tunneling

)ater in rush" *ussen Tunnel

$nrushing water" +implon Tunnel


5/20

Groundwater Control during Construction

,

ewatering at the Tunnel

*ace rainage .head of *ace

from /robe Holes

rainage from /ilot

0ore%Tunnel

Grouting

*reeing


6/20


1

+ealed tunnels do not inuence the groundwater

but their lining has to support full water pressure To estimate ground water load

mpirical ethod

.nalytical +olution

and umerical ethod


7/20


5

*actors that a6ecting water loads on the

underwater tunnel linings due to water ow are relative ground-lining permeability

relative ground-lining sti6ness

geometric factors such as

depth below the water body


8/20


7

T0 e8cavated tunnel +prayed shotcrete lining

$mpermeable geosynthetic membrane 9nal lining may consist of cast-in-place concrete"

precast concrete panels" or shotcrete


9/20

Drained tunnel

:

Hydrostatic pressure on lining relieved due to

drainage of water Groundwater penetrates the shotcrete shell

through 9ssures and ad hoc bored holes +ide pipes guide the groundwater to main

collector


10/20

!#

Drained tunnel

Geosynthetic sheet%strip are used


11/20

!!

Drained tunnel

Ground )ater ischarge into a &rained

circular tunnel(

+olution given by ;aymer< obtained with packer tests

appro8imate solution isotropic permeability

&


12/20

!2

Drained tunnel

+eepage *orce on rained

Tunnel

pressure e8erted by the ground upon the crown of an undrained tunnelis given by

ground pressure acting upon thecrown of a drained tunnel


13/20

!3

Drained tunnel

nvironmental 6ects of drainage

>euier arch dam &+witerland(


14/20

!4

Sealing (Waterproong o! Tunnel a"o#e Ground Water Ta"le

?mbrella waterproo9ng

protected against

downwards percolatingwater

water pressure &3-bar(water-tight concrete

high water pressure &up to!, bar( watertightmembranes


15/20

!,


Drained tunnel

Geospacers Geocomposite


16/20

!1


%ndrained tunnel

Geocompositeprotective

Geomembrane


17/20

!5

Smart Drains .n e6ective and long lasting solution for tunnel

drainage

micro channels start collect water" dirt and

particles are held back by in the soil gravity

separating action avoid clogging of drains


18/20

!7

Smart Drains

siphoning action The drain belts are inserted into the

collection pipes


19/20

!:

Smart Drains

also available in pipe

form

@logging and

sedimentation is

avoided


20/20

2#

Documents

Drained and water tight tunnels