Reinforcements

Reinforcements are horizontal reinforcing elements, which are placed into the soil to increase the slope stability utilizing their tensile strength. If the reinforcement intersects the slip surface, the force developed in the reinforcement enters the force equation of equilibrium of a given block. In the contrary case, the slope stability is not influenced.

The basic parameter of reinforcement is the tensile strength R_t. A design value of this parameter is used - i.e. the strength of reinforcement reduced by coefficients taking into account the effect of durability, creep and installation damage. The force transmitted by reinforcement can never exceed the assigned tensile strength R_t.

Scheme of accounting for reinforcement

The second characteristic is the pull-out strength T_p. This parameter determines the anchoring length, i.e. the required length of reinforcement in the soil, for which the reinforcement is fully stressed attaining the value R_t. Since the realistic values of the pull-out strength are difficult to determine, the program offers three options for their calculation, respectively for the calculation of the force F transmitted by the reinforcement.

Calculate reinforcement bearing capacity

The pull-out force F is given by:

where:	σ	-	normal stress due to self weight at the intersection of reinforcement and slip surface – see Fig.
	φ	-	angle of internal friction of soil
	C	-	coefficient of interaction (0,8 by default)
	l	-	length of reinforcement step joint behind the slip surface into the soil body

Input reinforcement anchor length l_k

An anchoring length l_k is specified. This parameter is determined by the shear strength developed between the reinforcement and the soil gradually increasing from zero to its limit value (measured from the end of reinforcement fixed in soil).

where:	l	-	length of reinforcement behind the slip surface into the soil body
	lk	-	anchoring length of reinforcement
	Rt	-	tensile strength

Input reinforcement pull-out resistance T_p

The pull-out force F is given by:

where:	l	-	length of reinforcement behind the slip surface into the soil body
	Tp	-	pull-out resistance of reinforcement