Warsaw, 27 April 2012
Item 463
REGULATION
OF THE MINISTER OF TRANSPORT, CONSTRUCTION AND MARITIME ECONOMY 1)
of 25 April 2012
on determining geotechnical conditions for building foundations
Pursuant to Article 34(6)(2) of the Act of 7 July 1994 – Construction Law (Journal of Laws of 2010 No. 243, item 1623, as amended2)), the following is enacted:
§ 1. This Regulation specifies detailed rules for determining geotechnical conditions for building foundations,
hereinafter referred to as “geotechnical foundation conditions.”
§ 2. Wherever this Regulation refers to specialist geotechnical works, it means a set of specialist construction works aimed at strengthening the ground subsoil, reinforcing existing foundations, carrying out complex foundation and earthworks, and ensuring the safe execution of a building. In particular, this includes: conventional and jet grouting, ground anchors, piles, micropiles, consolidation columns, reinforced fills, diaphragm walls, slurry walls, tunnels, shafts and caissons, and other specialized methods for performing earthworks and foundation works.
§ 3. 1. Determining geotechnical foundation conditions consists of:
1) assigning the building to an appropriate geotechnical category;
2) designing construction drainage systems;
3) preparing an assessment of the suitability of soils used in earth structures;
4) designing sealing barriers or screens;
5) determining bearing capacity, settlements and overall stability of the ground subsoil;
6) establishing the mutual interaction between the building and the ground subsoil during different stages of construction and operation,
and also the interaction between the building and adjacent structures;
7) assessing the stability of slopes, excavation faces and embankments;
8) selecting methods for ground improvement and stabilization of slopes, excavation faces and embankments;
9) evaluating the interaction between groundwater and the building;
10) assessing the degree of contamination of the ground subsoil and selecting methods for soil remediation.
2. The scope of activities carried out when determining geotechnical foundation conditions should depend on the geotechnical category assigned to the building.
3. Geotechnical foundation conditions are presented in the form of:
1) a geotechnical opinion;
2) ground investigation documentation;
3) a geotechnical design.
4. The form of presenting geotechnical foundation conditions and the scope of necessary investigations should be dependent on the geotechnical category assigned to the building.
§ 4. 1. The geotechnical category is determined in the geotechnical opinion depending on the complexity of ground conditions and on the building's structural system, which together characterize the potential for transmitting deformations and vibrations, the complexity of interactions, the degree of risk to life and property from structural failure, as well as the historical or technical value of the building and its potential for significant impact on the environment.
2. Ground conditions, depending on their complexity, are classified as:
1) simple – occurring where layers of soil are genetically and lithologically homogeneous, lying horizontally, and not including mineral weak-bearing soils, organic soils or uncontrolled fills, with the groundwater table below the design foundation level and with no occurrence of adverse geological phenomena;
2) complex – occurring where soil layers are heterogeneous, discontinuous, genetically and lithologically variable, including mineral weak-bearing soils, organic soils and uncontrolled fills, with the groundwater table at or above the design foundation level and with no occurrence of adverse geological phenomena;
3) complicated – occurring where soils are affected by adverse geological phenomena, especially karstic, landslide, suffosion, piping, glacitectonic processes, expansive or subsiding soils, in areas of mining damage, where discontinuous deformations of the rock mass are possible, in river valleys and deltas, and in marine areas.
3. The following geotechnical categories of a building are distinguished:
1) first geotechnical category, which covers the foundations of small buildings with statically determinate calculation schemes in simple ground conditions, for which minimal requirements can be met on the basis of experience and qualitative geotechnical investigations, such as:
a) one- or two-storey residential and utility buildings,
b) retaining walls and excavation supports where the level difference does not exceed 2.0 m,
c) excavations up to 1.2 m deep and embankments up to 3.0 m high, performed particularly for road construction, drainage works and pipeline installation;
2) second geotechnical category, which includes buildings founded in simple and complex ground conditions, requiring quantitative and qualitative assessment and analysis of geotechnical data, such as:
a) shallow or deep foundations,
b) retaining walls or other earth-retaining structures, subject to the reservation in item 1(b), holding back soil or water,
c) excavations, embankments (subject to the reservation in item 1(c)) and other earth structures,
d) bridge abutments and piers and quays,
e) ground anchors and other anchoring systems;
3) third geotechnical category, which includes:
a) buildings founded in complicated ground conditions,
b) unusual buildings, regardless of ground condition complexity, whose construction or use may create a serious hazard to users, e.g. power generation facilities, refineries, chemical plants, dams and other hydraulic structures with a retention height above 5.0 m, shipyard structures, artificial islands and drilling platforms and other complex offshore structures, or those whose designs contain novel technical solutions not established in national practice,
c) buildings classified as projects likely to have a significant environmental impact as specified in the Regulation of the Council of Ministers of 9 November 2010 on projects likely to have significant effects on the environment (Journal of Laws No. 213, item 1397),
d) high-rise buildings designed within existing urban development,
e) tall structures whose depth of direct foundation exceeds 5.0 m or which include more than one basement level,
f) tunnels in intact hard rock, in conditions not requiring special impermeability,
g) critical infrastructure facilities,
h) historic and monumental structures.
4. The geotechnical category of the whole building or of its individual parts is determined by the building designer on the basis of geotechnical investigations, the scope of which is agreed with the contractor for specialist geotechnical works.
5. If actual ground conditions differ from those assumed in the investigations, the building designer shall change the geotechnical category of the building accordingly.
§ 5. Geotechnical foundation conditions are established in particular on the basis of current results of ground investigations, analysis of archival data including assessment of geotechnical, engineering-geological and hydrogeological documentation, geodetic observations of the behavior of neighboring structures and other data concerning the subsoil of the site under investigation and its surroundings.
§ 6. 1. The scope of ground investigations is determined according to the geotechnical category of the building.
2. For buildings in the first geotechnical category the scope of ground investigations may be limited to boreholes and probing and to determination of soil type by macroscopic analysis. Geotechnical parameter values may be established using local correlation relationships.
3. For buildings in the second and third geotechnical categories the scope of investigations, in addition to the tests referred to in paragraph 2, should depend on the expected complexity of ground conditions and on the specifics and nature of the building or the type of planned geotechnical works and should determine:
1) soil types;
2) the physical and mechanical soil parameters, such as: internal friction angle, cohesion, undrained shear strength, compressibility or deformation modulus, obtained from laboratory or in-situ tests, in particular by methods such as:
a) static and dynamic probing,
b) pressuremeter and dilatometer tests,
c) vane probing,
d) plate load tests;
3) hydromechanical properties of groundwater where required.
4. For buildings in the third geotechnical category, the scope of investigations, beyond those referred to in paragraphs 2 and 3, should be additionally supplemented with tests necessary for conducting analytical and numerical calculations for the adopted geotechnical model of the subsoil, in agreement with the contractor performing specialist geotechnical works.
5. For earth structures and waste landfills classified in the second and third geotechnical categories, the scope of investigations, in addition to those referred to in paragraphs 2 and 3, should be supplemented by tests of:
1) hydraulic conductivity of soils carried out in the field and laboratory;
2) compaction characteristics of the subsoil and of materials used for construction;
3) materials used for sealing;
4) materials used in drainage structures.
6. For ground improvement works for buildings classified in the second and third geotechnical categories, in addition to the tests referred to in paragraphs 2 and 3, the investigation scope should be supplemented with tests of:
1) effects of ground improvement;
2) materials used for ground improvement.
7. The scope of investigations listed in paragraphs 2–6 may, as required, be extended to include additional ground tests, such as:
1) geophysical surveys;
2) tests on trial plots;
3) excavations exposing foundations;
4) tests for soil and groundwater contamination;
5) dynamic soil property tests;
6) remote sensing surveys.
8. Samples for laboratory tests should comply with Polish Standard PN-EN 1997-2 Eurocode 7: Geotechnical design – Part 2: Ground investigation and testing, and should be taken during boreholes, from trial pits, using appropriate sampling devices.
§ 7. 1. A geotechnical opinion shall be prepared for buildings of all geotechnical categories.
2. For buildings in the second and third geotechnical categories, ground investigation documentation and a geotechnical design shall also be prepared.
3. For buildings in the third geotechnical category and for complex ground conditions in the second category, engineering-geological documentation shall also be prepared, in accordance with the provisions of the Act of 9 June 2011 – Geological and Mining Law (Journal of Laws No. 163, item 981).
§ 8. The geotechnical opinion should establish the suitability of soils for construction purposes and indicate the geotechnical category of the building.
§ 9. Ground investigation documentation, in accordance with Polish Standards PN-EN 1997-1: Eurocode 7: Geotechnical design – Part 1: General rules and PN-EN 1997-2: Eurocode 7: Geotechnical design – Part 2: Ground investigation and testing, should include a description of the field and laboratory testing methodology, their results and interpretation, a geological model and a summary of the derived geotechnical parameter values for each layer.
§ 10. The geotechnical design, in accordance with Polish Standards PN-EN 1997-1: Eurocode 7: Geotechnical design – Part 1: General rules and PN-EN 1997-2: Eurocode 7: Geotechnical design – Part 2: Ground investigation and testing, should include:
1) forecast of changes in subsoil properties over time;
2) determination of design geotechnical parameters;
3) determination of partial safety factors for geotechnical calculations;
4) determination of actions from the ground;
5) adoption of a computational model of the subsoil, or in simple cases a design geotechnical section;
6) calculation of bearing capacity and settlement of the subsoil and of overall stability;
7) specification of data necessary for foundation design;
8) specification of tests required to ensure the required quality of earthworks and specialist geotechnical works;
9) assessment of harmful effects of groundwater on the building and methods to mitigate these risks;
10) determination of the scope of necessary monitoring of the completed building, adjacent structures and surrounding ground, required to identify hazards that may arise during construction or as a result thereof and during the building's operation.
§ 11. Provisions previously in force shall apply to buildings for which, before the entry into force of this Regulation:
1) an application for a building permit or a separate application for approval of the building design has been submitted, or
2) a notification of intention to carry out construction works has been made where a building permit is not required, or
3) a notification of change of use of a building or part of a building has been made.
§ 12. This Regulation enters into force on 29 April 2012.3)
Minister of Transport, Construction and Maritime Economy: S. Nowak
