Annex I.1

(informative)

(1) This is an example of deriving the undrained shear strength Cu; Cu can be obtained by using the following equation:

where:

pu is the ultimate contact pressure from the PLT results;

γ · z is the total stress (density times depth) at test level included when the test is conducted in a borehole with a diameter smaller than three times the diameter or width of the plate;

Nc is the bearing capacity factor; for circular plates is:

Nc = 6 for PLT on the subsoil surface;

Nc = 9 for PLT in boreholes of depths greater than four times the diameter or width of the plate.

For additional information and examples, see Annex M.

ANNEX I.2

(informative)

(1) This is an example of deriving the plate settlement modulus EPLT (secant modulus).

(2) For loading tests made at the ground level or in an excavation where the bottom is at least five times the plate diameter, the plate settlement modulus EPLT may be calculated from the general equation:

where:

Δp is the selected range of applied contact pressure considered;

Δs is the change in total settlement for the corresponding change in the applied contact pressure Δp including creep settlements;

b is the diameter of the plate;

is Poisson's ratio for the conditions of the test.

(3) If not determined in other ways, is equal to 0,5 for undrained conditions of cohesive soils and 0,3 for non-cohesive soils.

(4) If the test is made at the base of a borehole the value of EPLT may be calculated from the equation:

where:

Cz is a depth correction factor; an example for suggested values is given in figure I.1.

Figure I.1: Depth factor Cz as function of plate diameter b and depth z for PLT results obtained with a uniform circular load at the base of an unlined shaft (after Burland 1969)

For additional information and examples, see Annex M.

ANNEX I.3

(informative)

(1) This is an example of deriving the coefficient of subgrade reaction ks; ks may be calculated from the equation:

where:

Δp is the selected range of applied contact pressure considered;

Δs is the change in settlement for the corresponding change in applied contact pressure Δp including creep settlements.

(2) The dimensions of the loading plate should be stated when calculating values of ks.

ANNEX I.4

(informative)

(1) This is an example of deriving settlements directly. The settlements of the footing in sand may be derived empirically according to the relations given in figure I.3, if the ground beneath the footing to a depth larger than two times the width is the same as the ground beneath the plate (see figure I.2).

Figure I.2: Influenced area beneath a test plate and a footing

Figure I.3: Graph for calculations of settlement based on plate loading tests

For additional information and examples, see Annex M.

ANNEX J

(informative)

## Selection of the sampling method

Table J.1: Examples on sampling methods with respect to the sampling category in different soils; the abbreviations of the sampling methods are listed in table J.2
 Soil type Suitability depends on e.g. Category A Category B Category C Sampling method Clay - stiffness or strength-sensitivity PS-PUOS-TNW-PUOS-TNW-PE*)OS-TCW-PE*)CS-DTBS-TPBS-FD OS-TNW-PE OS-TCW-PECS-STAS*) AS Silt -stiffness or strength-sensitivity-groundwater table PS-PUOS-TNW-PUBS-TP CS-DT OS-TCW-PE AS CS-ST Sand -sizes of theparticles-density-groundwater table BS-TPOS-TNW-PU*)OS-TCW-PE*) OS-TCW-PE CS-DT AS CS-ST Gravel - size of the particles - density - groundwater table BS-TP OS-TCW-PE' CS-DT*) AS Peat -state of decay PS-PUOS-TNW-PUBS-TP CS-ST AS*) AS *) can be used only on very favourable conditions.

(2) The quality class of the sample for laboratory tests obtained by a certain sampling method also depends very strongly on:

• details of the sampler;
• carefulness of the sampling procedure.

Table J.2: Sampling methods and their abbreviations used in table J.1
 OS-TNW-PU open-tube samplers, thin-walled/pushed OS-TNW-PE open-tube samplers, thin-walled/percussion OS-TCW-PE open-tube samplers, thick-walled/percussion PS-PU Piston samplers/pushed CS-ST rotary core drilling, single tube, vibrocoring CS-DT rotary core drilling, double or triple tube AS Augering BS-TP block samplers/test pit BS-FD block samplers/from depth

For additional information and examples, see Annex M.

ANNEX K

(informative)

## This is an example of simplified weathering classification in six grades.

 Grade Degree of decomposition Diagnostic features in samples and cores I Fresh rock No visible sign of rock material weathering; perhaps slight discoloration on major discontinuity surfaces. II Slightly weathered rock Discoloration indicates weathering of rock material and discontinuity surfaces. III Moderately weathered rock Less than half of the rock material is decomposed or disintegrated to a soil. Fresh or discoloured rock is present either as a continuous framework or as corestones. IV Highly weathered rock More than half of the rock material is decomposed or disintegrated to a soil. Fresh or discoloured rock is present either as a discontinuous framework or as corestones. V Completely weathered rock All rock material is decomposed and/or disintegrated to soil. The original mass structure is still largely intact. VI Residual soil All rock material is converted to soil. The mass structure and material fabric are destroyed. There is a large change in volume, but the soil has not been significantly transported.

For additional information and examples, see Annex M.

Eurocode 7 Geotechnical design — Part 3: Design assisted by fieldtesting