A $3 \: m \times 3 \: m$ square precast reinforced concrete segments to be installed by pushing them through an existing railway embankment for making an underpass as shown in the figure. A reaction arrangement using precast PCC blocks placed on the ground is to be made for the jacks.

At each stage, the jacks are required to apply a force of $1875 \: kN$ to push the segment. The jacks will react against the rigid steel plate placed against the reaction arrangement. The footprint area of reaction arrangement on natural ground is $37.5 \: m^2$. The unit of weight of PCC block is $24 kN/m^3$. The properties of the natural ground are: $c:17 \: kPa; \: \phi=25^{\circ}$ and $\gamma=18 \: kN/m^3$. Assuming that the reaction arrangement has rough interface and has the same properties that of soil, the factor of safety (round off to $1$ decimal place) against shear failure is ________