A preliminary analysis of the ability of seismic liquefaction of soils (for example, water-saturated sandy-clay deposits in Kudepsta village, Adler district of Sochi)

Abstract

The territory of Sochi belongs to the 9-point seismicity zone according to the MSK-64 scale. Under the conditions of flooded sands and soft plastic loams, an earthquake can reach 10-point seismicity, which can create a very serious situation for the urban infrastructure. Using the example of soil analysis of the settlement of Kudepsta (the area of Big Sochi), a preliminary stage of risk assessment of liquefaction of weak water-saturated sediments under the influence of possible strong earthquakes is described. Prediction of the stability of various soil complexes to seismogenic liquefaction is made at a qualitative level, i. e. it is shown in principle is liquefaction possible or not. A quantitative assessment of this possibility (probability) is not made. A description of the sequence, content and the results performed during the analysis of procedures is given. In particular, it is shown that under the conditions of the studied area the soil and the loam with a thickness of 2-3 m can be classified as potentially liquefied soils. The loam lying at a depth of 5-10 m is considered to be practically non-liquefiable. Soils at intermediate depths require an additional study. The obtained data will be used in the further (quantitative) assessment of the probability of seismogenic liquefaction of the studied soils and the thickness of a potentially liquefied stratum. Seismic liquefaction of weak flooded soils during earthquakes, as a rule, manifests itself in the form of instantaneous precipitation and, as a result, massive destruction of buildings. Such earthquakes are characterized by cracks in the earth’s crust up to a meter wide, landslides and avalanches from the slopes, the destruction of stone buildings, the deformation of railway rails. Tectonic fragmentation of the region, rugged relief, excessive water cut contribute to the manifestation of large-scale landslides. In the zone of marine abrasion, there is a high probability of landslides associated with the destruction of port facilities. Over the past 100 years in this region earthquakes of more than 7 points occurred.