(Revised: 07/17/2015)
Class 1:
A Profile consisting of:
Rock of Material Classes 1 through 4, or
Rock of any characteristic, either shale-like or
crystalline in nature, which has a shear wave velocity greater than 2000 feet per
second, or
Stiff soil conditions where the soil depth is less
than 200 feet and the soil types overlying rock are stable deposits of
weathered bedrock of Material class 5.
Dense to very dense till, gravel or sand and gravel
of Material Classes 6 and 7.
Dense to very dense sand of Material Classes 8 and
9.
Dense inorganic silt of Material Class 9.
Stiff to hard clay of Material Class 10 with
un-drained shear strength of 2000 pounds per square foot or greater, or
Compacted granular fills provided that the fill
soils are compacted throughout as required in 780 CMR
1904.1.
Class 2:
A soil Profile meeting the requirements for S1
except the soil depth exceeds 200 feet, or
A soil profile which contains up to 40 feet of
medium stiff clay (Material class 10), with un-drained shear strength of 1000
pounds per square foot or greater, or
A soil profile which contains up to 40 feet of
medium dense gravel, sand and/or silt (Material classes 7 through 10), that is
not susceptible to liquefaction in accordance with 780 CMR
1802.2.
Class 3:
A soil profile containing 40 to 100 feet in
thickness of medium stiff clay (Material Class 10) with an un-drained shear
strength of 1000 pounds per square foot, or greater, with or without
intervening layers of granular soils, or
Up to 40 feet of soft clay (Material Class 10) with
un-drained shear strength of less than 1000 pounds per square foot, or
Up to 40 feet of very loose to loose gravel, sand
or silt (Material Classes 7 through 9), or
Up to 20 feet of organic soil (Material Class 11)
or loose or soft fill which was not placed in accordance with 780 CMR 1804.1.
Class 4:
A soil profile containing more than 100 feet of
medium stiff clay (Material Class 10) with un-drained shear strength of 1000
pounds per square foot or greater, with or without intervening layers of
granular soils, or
More than 40 feet of soft clay (Material Class 10)
with un-drained shear strength of less than 1000 pounds per square foot, or
More than 40 feet of very loose to loose sand or
silt (Material Classes 8 and 9), or
More than 20 feet of organic soil (Material Class
11), or
More than 20 feet of loose soft fill which was not
placed in accordance with 780 CMR 1804.1, or
More than
20 feet of soils of any type having a shear wave velocity of 500 feet per
second or less.
See also: