Fig 1.
Schematic showing the residual anchor force monitoring system of the earth anchor using the magnetic-elastic effect.
Fig 2.
The magnetic field generated by the solenoid coil.
Fig 3.
Hysteresis curve.
Fig 4.
The effect of tensile force in magnetic field.
Fig 5.
Conceptual diagram of an elasto-magnetic sensor.
Fig 6.
A magnetic field diagram outside a solenoid.
Fig 7.
Schematic diagram of mesh setting algorithm.
Table 1.
Anchor body and sensor head properties for magnetic field analysis.
Fig 8.
Magnetic field distribution (600[turns]) (a): Magnetic flux density distribution of the anchor head. (b): Magnetic flux density distribution of the wedge.
Fig 9.
Magnetic field distribution (1000[turns]) (a) Magnetic flux density distribution of the anchor head. (b) Wedge magnetic flux density distribution.
Fig 10.
Magnetic field distribution analysis results for the cases of coil setup directly installed to individual tension member (full coil direction; counterclockwise) (a) Magnetic field distribution map (X-Z plane, whole). (b) Magnetic field distribution map (X-Z plane, per coil). (c) Wedge magnetization. (d) Anchor head magnetization.
Fig 11.
Magnetic field distribution analysis results for the cases of coil setup directly installed to individual tension member (left side coil direction; counterclockwise, right side coil direction; clockwise) (a) Magnetic field distribution map (X-Z plane, whole). (b) Magnetic field distribution map (X-Z plane, per coil). (c) Wedge magnetization. (d) Anchor head magnetization.
Fig 12.
Elasto-magnetic sensor manufacturing (a) Elasto-magnetic sensor head. (b) Additional magnetization coil for the magnetization of the wedge.
Fig 13.
Installation of load control and measuring devices used in the test.
Fig 14.
Elasto-magnetic sensor installation view.
Fig 15.
Changes in the hysteresis curve area when tension is unloaded (a) B-H curve (b) Raw area. (c) Normalized area.
Fig 16.
Temperature graph by test load step (a) Test 1. (b) Test 3. (c) Test 4. (d) Test 5.
Table 2.
Temperature by test load step.
Fig 17.
Comparison of B-H curve area and temperature change by test load step (amplitude is normalized) (a) Test 1. (b) Test 3. (c) Test 4. (d) Test 5.
Table 3.
The correlation coefficient between area and the temperature of B-H curve.
Fig 18.
Linear regression results (a) Test 1. (b) Test 2. (c) Test 3. (d) Test 4. (e) Test 5.
Table 4.
The correlation coefficient between area and the temperature of B-H curve.
Fig 19.
Validation results of residual tensile force estimation.
Table 5.
Validation results of tensile force estimation for Test 4 and 5.