Contents preface (VII) introduction 1—37

x I

y

F

x

I

y − 1

|F

= a SG 1 +

J

+ G 1

+

J

|H

100K

H

100K

T

R

I

U

F

x

y

x I |F

|

aG 1

+

J SG 1 +

J

−

1V

H

100K |H

100K

|

=

RF

T

x

I

U

W

SG

1 +

J − 1V

T^H

100K

W

F

x I F

100 + xI ^y^− ^1

(TLC) G

J G

100

J

a =

H 100K H

K

F 100 + xI ^y

− 1

G

100

J

H

K

F		x I	y−2	F		x I	1U
			|
+ G 1	+		J		+ ... + G 1	+		J	V
H		100K		H		100K	|
									W

(5.24)

For lining to be economically feasible, the value of a should be less than the annual benefit B_t i.e., the ratio B_t/a should be greater than unity.
5.14.6. Types of Lining
Types of lining are generally classified according to the materials used for their construction. Concrete, rock masonry, brick masonry, bentonite-earth mixtures, natural clays of low permeability, and different mixtures of rubble, plastic, and asphaltic materials are the commonly used materials for canal lining. The suitability of the lining material is decided by: (i ) economy, (ii) structural stability, (iii) durability, (iv) reparability, (v) impermeability, (vi) hydraulic efficiency, and (vii) resistance to erosion (15). The principal types of lining are as follows:
(i) Concrete lining, (ii) Shotcrete lining,

(iii) Precast concrete lining, (iv) Lime concrete lining, (v) Stone masonry lining, (vi) Brick lining,

(vii) Boulder lining, (viii) Asphaltic lining, and

(ix) Earth lining.