free website hit counter Dynamic Cone Penetration Test

Dynamic Cone Penetration Test (DCPT)

In geotechnical engineering and foundation engineering standard penetration tests (SPT)1 and cone penetration (CPT)2 in situ (In-Site) widely used to check the soil conditions of project on site location in order to analyze it and used the structural design. SPT test can be done by a dynamic mechanism with a guided sampler and help of hammer blows, while in CPT test penetration test cone-guided by a semi-static mechanism. In a dynamic cone penetration testing DCPT3 guided with a penetrometer cone by a dynamic mechanism and Indicative the property of both methods.

DCPT tests done by two persons and launched a quick test, for the run and check the results at the project site. This obtained Due to the economic and simplicity as well as a better understanding of the results, it can help to reduce the costs and to efforts to investigate the soil.

In Iran to conduct the DCPT test in is used 10-kilogram hammer it so-called "10-kilogram German handy hammer" will be compared with SPT Tables and following formula results.

Standard:

DIN 4094

  • 10_Lb_SPT_11
Name of
Apparatus
Shafts
Diameter
d
(mm)
Head Diameter
do
(mm)
Head Angel
 
degree
Hammer
Weight
w
(kg)
Falling
Height
h
(cm)
Head Area
A
(cm2)
Depth of
Penetration
in Soil
D
(cm)
Energy consumption
per unit area of the head
E
(kg/cm)
Total Energy
or Work
E'
(kg/cm2)
Hit ratio in comparison
with American SPT
Light German SPT
22
35.6
90
10
50
10
20
50
2.5 n
3.20
Heavy German SPT
32
43.7
90
50
50
15
20
167
8.4 n
0.95
American SPT
36
50.8
-
63.5
76.2
20.2
30
240
8.0 n
1.0
  • Formulas for calculating the energy used in the experiment:

1. E = (w×h)⁄A     kg/cm                                2. E' = ((w×h)⁄A)×(n/D)  kg/cm2

n : Number of blows

  • Formula converting SPT German style to SPT American:

N30 = N20 / 3.2

N20number of hit in SPT test with Light German hammer for 20 cm penetration in the soil, hit count for three times, each time 10 cm penetration in the soil is measured, hits of the first 10 cm of un compressed soil will be ignored, The total number of second and third beats 10 cm N20 is shown and measure as soil resistance.
N30number of hit in SPT test Standard American Hammer for 30 cm penetration in the soil, hit count for three times, each time 15 cm penetration in the soil is measured, hits of the first 15 cm of un compressed soil will be ignored, The total number of second and third beats 15 cm N30 is shown and measure as soil resistance.

Light German SPT

All joints are screwed.
Total weight of Hammer: 20 Kg
Total height of the Hammer: 145 Cm
Hammer Body Material: CK45
Cone Penetration Material: CK45 - 40 Rockwell Hardened
Falling Height 50 Cm

SMSO-8100

 

 
 
 
 
 

1. SPT = Standard Penetration Test
2. CPT = Cone Penetration Test
3. DCPT = Dynamic Cone Penetration Test
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