The rigid rough square footing of size 100 X 100 mm was placed at the middle of the surface of the unsaturated sample. The footing was fixed at the chosen angle with the loading piston. The displacement transducer was connected with the piston for the measurement of the displacement [R-Displacement {Fig. 5(a)}] during loading. Two external, vertical and horizontal displacement transducer were also placed precisely at the middle of the footing. These transducers were placed perfectly in vertical and horizontal plane at the center of the footing as shown in Fig. 5(a). The footing settlements were measured with a resolution equal to 0.001 mm and the accuracy of the applied load [R-Force] was equal to 0.05 %. A National Instrument (NI) **data** logging system was used to collect all the experimental data. The noisy signal received from load and displacement transducers of the device was filtered using third order Zero-Phase Low Pass Butterworth filter in MATLAB. To obtain a smooth signal after filtering, the unwanted transients were eliminated by using Median Filtering technique available in MATLAB. The loading piston was connected with the footing at an angle of 15 degrees with vertical Fig. 5(a). This provides an angular loading to the footing of 15 degrees to impose a coupled cyclic excitation. A force controlled coupled harmonic excitation from Equation 1 is imposed to the footing at a constant amplitude of 0.25kN, with the frequency of 0.1Hz with respective static load as shown in Fig. 5(b).
[ ] ( ) t A F Force R st cyclic ω cos * + = −(1)
Where, Fst = Static Load A = Amplitude = 0.25kN ω = Angular Frequency = 2*π*f f = frequency = 0.1Hz t = Total time of loading = 0 to 5 x 10 5 sec for 50000 cycles.