Embankments contained by two tensioned retaining walls are an opportunity to control our measurements. Tests are performed at both ends of the tie rods and the results are compared (Fig. 7.1).

Fig. 7.1
figure 1

Source Rincent BTP—Recife

Horizontal ties across an embankment.

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The dynamic stiffness is calculated from the eight mechanical impedance tests performed on the tie rod head.

Two tie rods were tested on both sides of the embankment (Figs. 7.2 and 7.3).

Fig. 7.2
figure 2

Results of stiffness (N/m) and force (t)

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Fig. 7.3
figure 3

Walls and anchors

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First case

The values for the forces are as follows, 8.7 tons and 8.6 tons, i.e. 0.1-ton difference.

Second case

The force values are 6.9 tons and 7.1 tons or 0.2ton difference.

The measurement uncertainty is less than 0.2 ton.

On another site, tests were performed with the following results.

The characteristic of the tie rods being formed by a central plate and two bars, 16 acquisitions were performed, 8 on the left bar, 8 on the right bar. Each of these acquisitions results in a dynamic stiffness value.

T1

Left

3,67E + 08

8,4t

Right

3,86E + 08

8,7t

T2

Left

4,43E + 08

4,43t

Right

4,40E + 08

4,40t

T3

Left

5,04E + 08

10,3t

Right

4,82E + 08

10,0t

The differentials of the internal force values are: 0.3 ton—0 ton and 0.3 ton.

Five tests were performed on horizontal ties the difference between the calculated forces on both sides of the tie backfill is less than 0.5 ton (Fig. 7.4).

Fig. 7.4
figure 4

Histogram of differences

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