Reinforcements
Reinforcements or overhangs of mesh behind the wall, respectively, may considerably increase the wall stability. The basic parameter of reinforcement is the tensile strength Rt. A design value of this parameter is used in all programs (except for the Redi-Rock wall program), i.e. the tensile strength of reinforcement reduced by coefficients taking into account the effect of durability, creep, environmental chemistry and installation damage. The force transmitted by reinforcement can never exceed the assigned tensile strength Rt (default value of 40 kN/m is used for gabions).
The second characteristic is the pull-out strength Tp. 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 Rt. 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.
Length of mesh step joint or reinforcement behind blocks, respectively
Calculate pull-out force
The pull-out force F is given by:
where: | σ | - | normal stress due to self-weight at the intersection of mesh and slip surface |
φ | - | angle of internal friction of soil | |
C | - | coefficient of interaction (0,8 by default) | |
le | - | length of mesh step joint behind the slip surface into the soil body |
Computation of the angle υa is described in the chapter earth wedge.
Input reinforcement anchor length lk
An anchoring length lk is specified. This parameter is determined by the shear strength developed between the mesh and the soil gradually increasing from zero to its limit value (measured from the end of reinforcement fixed in soil).
where: | le | - | length of mesh step joint behind the slip surface into the soil body |
lk | - | anchoring length of reinforcement | |
Rt | - | tensile strength |
Input mesh pull-out resistance Tp
The pull-out force F is given by:
where: | le | - | length of mesh step joint behind the slip surface into the soil body |
Tp | - | pull-out resistance of the mesh |