Limit deviation of overburden thickness       

Executive standard：HG/T 3647--2014

Nominal thickness of upper
and lower cover

Limit deviation

≤4

Upper deviation: Unspecified lower
deviation：0.2mm

＞4

Upper deviation: Unspecified lower
eviation: 5% of basic size

Physical properties of overburden

Executive standard：HG/T3647--2014

project

index

H

D

L

tensile strength Mpa   (Not less than)

24

18

15

Elongation at break/%   (Not less than)

450

400

350

Wear volume/mm3

120

100

200

Aging test（70℃×168h）Tensile
strength change rate/% elongation
change rate at break/%

-25~+25

-25~+25

-25~+25

Cold resistance

Tensile Strength Change Rate/%

C1(-45℃)

±20

C2(-50℃)

±25

Change rate of elongation at break/%

C1(-45℃)

±20

C2(-50℃)

±30

notes：C1-----The ambient temperature is：-45℃~+45℃；
C2-----The ambient temperature is -50℃~+45℃