apuntes correcciones spt

8/9/2019 Apuntes Correcciones SPT

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Load

Relative Density of Sand, D r 0 0.2 0.4 0.6 0.8 1.0

A. General Shear

B. Local Shear

C. Punching Shear

S e t

t l e m e n

t

Load

S e t

t l e m e n

t

Load

S e t

t l e m e n

t

Ultimate Load

DepthSurface

0

1

2

3

4

5

R e l a t

i v e

D e p

t h o

f F o u n

d a t

i o n

D / B

^

Test at Greater

Test

Modes of Failure of Model Footings in Chattahoochee

General

Local Shear

Shear

PunchingShear

B^ = B for a Square or Circular Footing.

B^ = 2BL/(B+L) for a Rectangular Footing.

Modes of Bearing Capacity Failure (76) Sand (20,76)

A dapted from Vesic (197 3) JSMFD, ASCE, 99(SMI)

Very loose Very Dense

140

Loose Medium Dense

0

10

20

30

40

50

60

130

120

100

90

80

70

60

50

40

30

20

10

0

N

N r

N q

S t a n

d a r

d P e n e t r a

t i o n

R e s

i s t a n c e

N ,

b l o w s /

f t

B e a r i n g

C a p a c

i t y

F a c

t o r s ,

N r

a n d N

q110

28 30 32 34 36 38 40 42 44

Angle of Internal Friction, , degrees

Curves showing the relationship between bearing-capacity factorsand , as determined by theory, and rough empirical relationshipbetween bearing capacity factors or and values of standard

penetration resistance N.

Adapted from Peck, Hanson & Thornburn (1974)


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SPT N Value (Blows/30cm)0 20 40 60 80 100

1

0

D r = 80%

Dr = 40%

2

3

v o ( k g

/ c m

2 )

Gibbs & Holtz (1957)Peck & Bazaraa (1969)Marcuson & Bieganousky (1976)

Schultze & Melzer (1965)

V e r

t i c a

l S t r e s s ,

Fig. 47. Empirical correlations between standard penetrationresistance and relative density for cohesionless soils.

Adapted from Ladd et al. (1977) 9 th ICFMFE

N, Blows/Foot

0 40 80 120 160 200

DR

DR /

0

2

4

6

8

= 100 %(Gibbs and Holtz)

Points omitted in thisarea

= 100 %(Bazaraa)

E f f e c

t i v e

O v e r

b u r d e n

P r e s s u r e ,

K i p s

S q u a r e

F o o

t

10

Dry Cohesionless Soil

Submerged CoarseCohesionless Soil

Results of Standard Penetration Tests for Very Dense SandsAdapted from Peck & Bazarra (1969)


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45

40

A n g

l e o

f I n t e r n a l

F r i c t

i o n

` ( D e g r e e s

)

35

30

25

20

R e l a t i v e D e

n s i t y1 0 0 %

i n t h i s ra nge

a n d

0

2 5 %

5 0 %

7 5 %

( )

` Obtained from effectivestress failure envelopesapproximate correlation

is for cohesionlessmaterials without

plastic fines

MLSM

SP

SWGP

GW

Angle of Internal Friction Vs Density For Coarse Grained Soils

Material Type

75 80 90 100 110 120 130 140 150

Dry Unit Weight ( D

), PCF(G = 2.68)

1.2 1.1 1.0 0.9 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15

Void Ratio, e

0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15

Porosity, n

Correlations Of Strength Characteristics For Granular Soils

Adapted from NAVFAC DM-7.1 (5/82) p 7.1 - 149


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