The article presents the results of numerical modeling assessing the effectiveness of vibration barriers for protecting rail transport infrastructure elements, specifically tram tracks and subway tunnels, from vibrational impact. The study examines three types of structures: horizontal, vertical, and combined barriers made from stone wool, expanded polystyrene (EPS), and extruded polystyrene (XPS). The methodology is based on solving the elastodynamic equations in the frequency domain using a finite-difference scheme that accounts for the free surface and utilizes perfectly matched layers (PMLs). The results indicated that horizontal barriers are most effective when using XPS (up to 70
The paper describes the reasons for the destruction caused by Spitak earthquake (December 7, 1988) and its socioeconomic impacts on the population from the time of the disaster to the present. Study of the aftermath of devastating earthquakes helps both to prepare for future seismic disasters and to better understand how to cope with their consequences. The Spitak earthquake triggered changes in approaches to construction in seismically hazardous zones promoting new standards and technologies for earthquake-resistant construction to become a priority for many countries. The discussed issues are relevant and require thorough studies of preparatory work and seismic hazard assessment in the study area.
The article experimentally studies the effectiveness of trench vibration barriers for the protection of buildings and engineering objects from anthropogenic vibrations. We consider vibration barriers made of such materials as expanded clay and expanded (EPS) and extruded (XPS) polystyrene foam. Experiments are conducted in a frequency range from 1 to 450 Hz, corresponding to vibration sources of different types such as: railroad and road transportation, industrial plants, intensive construction works, etc. The average values of vibration suppression efficiency in the whole frequency range studied were 55, 67, and 72
The article presents a brief overview of soil classifications and response spectra adopted in the building codes of the European Union and 15 other countries possessing seismically active regions, such as the United States, Japan, Australia and New Zealand, South Africa, Turkey, Iran, Kazakhstan, Kyrgyzstan, Armenia, Azerbaijan, Ukraine, Uzbekistan, Saudi Arabia, and China. The descriptions are based on regulatory documents, commentaries on standards, and scientific publications. The review indicated that classification of soil conditions and descriptions of response spectra in the Russian building codes SP14.13330.2018 significantly lag behind their foreign counterparts and do not provide necessary reliability of seismic motion assessments; also, an unreasonably wide range of S-wave velocities is defined for soils of category 2. To improve the situation, we suggest the following: (1) increase the number of soil categories in the building codes of Russian Federation to five main categories, including the category of soils with resonance properties, and two additional categories that require special investigations, and balance the ranges of S-wave velocities; (2) define two groups of response spectra for the main types of soils, for stronger and weaker earthquakes, as done in the Eurocodes; (3) include determination of predominant periods of vibrations of soil strata in studies of site conditions; (4) introduce corrections for topographic effects during construction in mountainous areas. These adjustments will not require substantial efforts, but will lead to a significant increase in the reliability of seismic motion assessments.
Current strain analysis for Obninsk observatory are presented. An extension rate of 5 × 10-9/y was recorded for the central part of European Russia using satellite geodesy. Preliminary results for a new laser extensometer installed in the Obninsk underground gallery (55.12° N, 36.59° E) are presented. The instrument with a 36 m base was an installed at depth of 30 m, along latitude and longitude. In this case, both seismic waves from earthquakes, tidal strain, and long-period signals associated with tectonic processes are recorded. Original strain data presented for July–September 2024 year period. Analysis of record noise is developed. Microseismic waves with periods from 10 to 50 s are presented. The long-period part with periods from 18 to 38 and 291 h connected with meteorological effects. Noise influence was excepted and for tidal analysis of difference strain a 70-day record are used. The Shida tidal parameter is studied. As a result of the study, it is shown that old results by measurements with gravimeters, tube-extensometers, and tiltmeters are related to old elastic tidal models. Our new results show accordance with DDW99 Earth tidal model with viscosity-elastic mantle.
