HAD101/12-1990 in English

1.1 General

The foundation of nuclear power plant is composed of the base structure, the engineering supporting structure, and the underlying soil and rock material at a certain depth and distance. The depth and distance of underlying stratum shall be determined according to that their properties do not influence the safety of nuclear power plant any more. The foundation materials may cause the structural stress of nuclear power plant exceeding the design limit as the foundation transmits the ground vibration movement exceeding the structural design limit of nuclear power plant or due to the settlement or sliding of foundation, and hereby the safety of nuclear power plant is influenced, and this subject must be taken into consideration properly during site selection of nuclear power plant.
The design basis of nuclear power plant requires that the nuclear power plant and its systems shall bear the dynamic load caused by the specified ground movement or design earthquake. Besides, the nuclear power plant generally adopts such structure with the foundation and underground materials (soil and rock) bearing the heavy load. In consideration of these two factors, it is required to make a detailed study on the interaction issue of structure and foundation material of nuclear power plant. The interaction effect shall be studied by geotechnical engineering method, and this is a booming course. Geotechnical investigation generally includes field study and laboratory study, for the purpose of determining the parameters and properties of underground materials and also determining the properties of underground materials under the design load condition through analysis.
The design basis earthquake determined per the method stated in the Guideline "Earthquake Problems in Relation to Nuclear Power Plant Sitting" (HAD 101/01) is used as the input data of foundation ground motion of nuclear power plant. The properties of underground materials and the interaction of underground materials with the structure of nuclear power plant provide one standard for nuclear power plant design to obtain the sufficient safety margin . Therefore, proper site investigation method and analytical model shall be selected for the purpose of obtaining conservative result. When the plant site is with the complicated, dramatic change or unknown characteristics (e.g. the ground surface has fracture or cave, etc.), more advanced and sensitive analytical techniques shall be adopted. Methods proposed in this guideline are universally applicable to all kinds of underground materials.

1.2 To-be-settled Problems

The problems to be settled are related to the properties of underground materials under the design load condition. Table 1 gives the major range requiring analysis as well as the main parameters and coefficients involved.
The nonuniformity of underground materials will cause the variation in actual measurement property, so that the safety analysis must reserve proper margin.