Part A - Introduction 
11 
Methods of carrying out geotechnical surveys and investigations can be divided into the fol 
lowing groups: 
• geophysical and 
• geotechnical investigation methods. 
Geophysical methods are indirect methods (sonars, seismics, echosounding equipment, etc.). 
Geotechnical methods comprise field and laboratory studies. Field investigations consist of 
direct exposure, primarily to recover sediment samples (boreholes) and indirect exposure 
(probes) as well as field tests such as manual vane tests or pressiometric tests in the bore 
hole. 
It may be expedient to carry out further investigations to aid planning such as e. g. pile driving 
or pile load tests. Carrying out pile load tests in the construction phase as part of verification 
of bearing capacities (execution phase) is regulated in the Standard Design. 
Sediment characteristics are deducted as part of laboratory or field tests in exceptional cir 
cumstances, or derived from field investigations. The type and the scope of such surveys and 
investigations for individual project phases are illustrated in Table 2. 
The concept illustrated in this guideline defines the minimum scope of geotechnical surveys 
and investigations in general cases. This is specified in Part B and Part C. 
4 Geotechnical expert 
Guidelines for geotechnical experts (Sachverständige für Geotechnik) in DIN EN 1997 along 
with the supplementary guidelines in DIN 1054 and DIN 4020 have been refined and adapted 
for offshore structures as follows: 
For planning and carrying out geotechnical surveys, investigations and assessments, the ap 
plicant or approval holder must ensure that even in the development phase (in accordance 
with Part A, Table 2) 
• a suitably qualified and independent geotechnical expert 
• with documented experience in such complex construction projects 
has to be involved. This measure should ensure that the soil is recorded as a non-normative 
part of the supporting structure with regard to size and scope in accordance with accepted 
technological standards and taken into account in plans and during implementation. 
The geotechnical expert acts on behalf of the applicant or approval holder and is responsible 
for geotechnical surveys, investigations and assessments which are part of the planning basis 
for the objects of the construction project. The expert’s tasks individually arise from 
DIN 4020. 
The geotechnical expert correspondingly develops the geotechnical planning basis for the 
construction project for the applicant or approval holder. The expert 
• plans the preliminary geotechnical survey and the main geotechnical survey, 
• accompanies the execution of the preliminary geotechnical survey and the main geotechni 
cal survey, 
• develops the geotechnical site survey reports in accordance with Part C, Section 4.2, 
• develops the soil and foundation expertise in accordance with Part C, Section 4.3,