Abstract
The construction of buildings and structures in seismically hazardous areas is closely connected with the solution of the question of the dynamic stability of the soil base. World experience shows that the most destructive effect of seismic action is dynamic liquefaction. The probability of occurrence and intensity of this process are determined by the geological and hydrogeological structure of the soil massif. Based on the results of special laboratory and field dynamic tests of soils, it is not always possible to completely exclude the possibility of developing this extremely negative process. In this paper, the main stages of the analysis of the dynamic stability of the soil of the foundations of buildings and structures in complex engineering-geological conditions are presented. A brief review of existing domestic and foreign measures for the protection of buildings and structures from the dynamic dilution of soils is given. Information is provided on the applicability and comparative effectiveness of the methods in question.
Highlights
Where: amax is the peak value of the horizontal acceleration on the surface of the ground; g acceleration of gravity; γ is the specific gravity of the soil; rd is the stress reduction coefficient, taking into account the deformability of the soil column, the value of which is less than one
Analysis of the dynamic liquefaction process can be performed by comparing the tangential stress caused by the seismic load and the tangential stress required to initiate the liquefaction of the soil, or the level of shear strain amplitude that is considered unacceptable for design [15,16,17]
Using the formula (2), it is possible to calculate the cyclic stress that is valid for a given seismic action, and the strength of the soil under dynamic influence can be determined from the results of soil tests in dynamic triaxial compression devices [18,19,20]
Summary
The value of the cyclic tangential stress at any point below the horizontal surface of the earth during an earthquake when passing from below the shear wave can be determined using the method proposed by Seed H.B. and Idriss I.M. [1,2,3]. The value of the cyclic tangential stress at any point below the horizontal surface of the earth during an earthquake when passing from below the shear wave can be determined using the method proposed by Seed H.B. and Idriss I.M. If we express the relative magnitude of the applied stresses through the relative equivalent voltage τav / σ'z, the corresponding strength must be expressed in terms of the relative equivalent stress τav, l / σ'z In this case, τav is the average amplitude of the cyclic action, which is 0.65 of the maximum shear stress τmax. The relative level of tangential stresses τav / σ'z acting in the ground is often called the reduced cyclic shear stress CSR (cyclic stress ratio), and the value of the cyclic strength is called the reduced cyclic resistance of the CRR (cyclic resistance ratio). Calculationexperimental methods for estimating the potential (dilution potential) are based on a comparison of the values of CSR and CRR
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