### Glossary of terms

### Plate load test

#### The deformation modulus E_{v}

The **deformation modulus** E_{v} is a parameter for the deformability of the soil. Decisive – for the assessment of compression – is both the ratio of the values E_{v2}: E_{v1}, and the value E_{v2}. According to DIN 18134 E_{v} is determined by a polynomial of 2nd degree and the method of least squares. The physical unit is NM/m².

E_{v} = 0,75 * (plate diameter D [mm]) * (Difference of the normal stress between the loads of 0,3*σ_{max} and 0,7*σ_{max} [MN/m²]) / (Difference of the settlement of the load plate at these load steps [mm]).

**The deformation modulus M _{E}**

The

**deformation modulus**M

_{E}is a parameter for the deformability of the soil. (Switzerland, Slovenia)

M

_{E}= (plate diameter D [mm]) * (Difference of the normal stress between two loads [MN/m²}) / (Difference of the settlement of the load plate at these load steps [mm])

**The deformation modulus M _{D}**

The

**deformation modulus**M

_{E}is a parameter for the deformability of the soil. (Italy)

M

_{D}= (plate diameter D [mm]) * (Difference of the normal stress between two loads [MN/m²}) / (Difference of the settlement of the load plate at these load steps [mm])

**The deformation modulus E _{v1}, E_{v2}, E_{v3}**

E

_{v1}is the modulus of the first load cycle of the plate load test. Physical unit is MN/m².

E

_{v2}is the modulus of the second load cycle of the plate load test. Physical unit is MN/m².

E

_{v3}is the modulus of the third load cycle of the plate load test. Physical unit is MN/m². (rare)

**Subgrade reaction k _{s}**

The Westergaard’s modulus of subgrade reaction k

_{s}is a parameter of the resilience of the soil surface under a distributed load. The average normal stress at a settlement of the load plate of 1.25 mm is measured. (according to DIN18134). The diameter of the load plate is typically 762mm.