Véas-Souche Theory
The critical force Ncr is calculated according to the formula [1]:
where: | lp | - | effective micropile length (free length + 1/2 root length) |
EI | - | bending stiffness of micropile reinforcement | |
Er | - | ||
m | - | number of half-waves |
The critical force Ncr is taken as a minimum of function (1). It is achieved for the length of half-wave:
The number of half-waves n is based on formula (2):
Let's introduce the dimensionless parameter ω, calculated according to the formula:
where: | lv | - | length of micropile above the terrain |
and another dimensionless quantify, taken according to the formula:
Relations between formulas (3), (4) and (5) are described in the article [2] using the charts. The critical force Ncr is calculated from the dimensionless quantify (5), which is determined from the charts for known values of ω and m.
Literature:
[1] Timoshenko, S. P.: Theory of Elastic Stability, New York, 1936
[2] Véase, Souche: Étude du fla,berment de pieux partiellernent immergés dans offrant latéralement une réaction élastique pure, Annales de I’ITBTP, No. 423, Sene Soils et Foundations, 187, mars - avril 1984, str. 38 - 60 (in French)