Dewatering, waterproofing and drainage - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 189

Table 5-5 Water permeability of rock ( k G ) and rock mass ( k F ) from C. Louis [125].

Rock Rock with one joint per metre

Rock type k G

cm/s

Joint width
mm

k F in the joint direction
cm/s

(0.36 to 23.0) 10 -13 0.7 ∙ 10 -4 1. Limestones 0.1

2. Sandstone

(0.29 to 6.0) 10 -11
(0.21 to 2.0) 10 -11

0.6 ∙ 10 -3
0.5 ∙ 10 -2

Carboniferous 0.2

0.4 Devonian

3. Mixed rocks

(0.33 to 33.0) 10 -12
(0.85 to 130.0) 10 -13
(0.27 to 80.0) 10 -12

2.5 ∙ 10 -2
0.7 ∙ 10 -1

sandy-calcareous 0.7

1.0 clayey-sandy

calcarious-clayey

(0.5 to 2.0) 10 -10 4. Granite 2.0 0.6

(0.7 to 1.6) 10 -10 0.5 ∙ 10 1 5. Shale 4.0

(0.7 to 120.0) 10 -9 6. Limestones

(0.5 to 1.2) 10 -8 1.6 ∙ 10 1 7. Dolomite 6.0

5.2.1.3 Payment and quantity measurement
The reference quantity and measurement point of the incidental water quantity in l/s must
be clearly regulated and specified in the contract between the employer and the contractor
in order to avoid payment difficulties. Depending on the conditions at the face, it should
be specified whether the reference quantity is measured “per advance face”, “per 10 m of
tunnel”, “per 30 m behind the face” or “total water quantity at tunnel exit” [130].

DIN 18 312. German construction contract procedures (VOB) - Part C: General tech-
nical specifications for construction contracts (ATV) - Underground construction work”
(12/2002) [59] includes the following statements to describe dewatering measures during
tunnel construction in Section 0.2:
0.2.18 Type and extent of measures to collect, drain and if required treat groundwater
during the construction period.
0.2.19 The limit water quantity for groundwater.
The area for the determination of the limit water quantity is given in DIN 18312 as
maximum 50 m from the face (Section 4.1.4 of the standard). All costs arising from
water ingress below this limit quantity during excavation and support works are deemed
included in the estimation of unit prices for excavation in the relevant tunnelling class
and are not paid separately. Only when this limit is exceeded can the contractor claim
extra payment. The water quantity for payment purposes is then determined from the
quantity drained from the tunnel less the quantity of service water supplied (Section 5.2
of the standard).