1949
Technical Committee 207 /
Comité technique 207
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Nail Movement (mm)
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Mobilised Skin Friction (kPa)
Legend:
Level 2 - 3
Level 3 - 4
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Preliminary Soil Nail Pullout Test (Y-7)
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Nail Movement (mm)
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Mobilised Skin Friction (kPa)
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Legend:
Level 2 - 3
Level 3 - 4
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Preliminary Soil Nail Pullout Test (W/X-16)
4 RESULTS OF INSTRUMENTED PULL-OUT TESTS
The test procedures and testing sequence of the soil nails are in
accordance with FHWA 1998 and the loading schedule is
summarised in Table 2. The pull-out test results showing the
mobilised skin friction vs nail movement are shown in Figures 4
to 6.
Table 2. Pull-out tests loading schedule (FHWA 1998).
Load
Hold Time (minutes)
0.25 DTL
10
0.50 DTL
10
0.75 DTL
10
1.00 DTL
10
1.25 DTL
10
1.50 DTL (Creep Test)
60
1.75 DTL
10
2.00 DTL
60
Repeat cycle if test load increased to 3.00 DTL
Note:
1. DTL
–
Design test load
2. Test load limited to maximum 80% yield strength of nail
reinforcement
The longer holding time of 60 minutes at 1.50 DTL and 2.00
DTL is to monitor creep movement. The acceptance criteria is
total creep movement of less than 2mm per log cycle of time
between the 6 and 60 minute readings and the creep rate is
linear or decreasing throughout the creep test load hold period.
Figure 4. Pull-out test results for nail Y-7.
Figure 5. Pull-out test results for nail W/X-16.
Figure 3. Typical details of instrumented preliminary soil nail.
