1 Central Asian Institute of Applied Earth Research (CAIAG), Bishkek, Kyrgyzstan
2 Research Institute of «Seismic Resistant Construction», Bishkek, Kyrgyzstan
3 Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Russian Academy of Sciences, Moscow, Russia
4Institute of Marine Geology and Geophysics, Far East Division, Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia
Abstract. The most widespread methods of seismic engineering are the methods based on the analysis of the microseisms, which is due to the economical reasons and simplicity implementation of this approach in different practical situations. It was shown that the analysis of the reaction of buildings on microseisms allows, as a rule, to obtain sufficiently complete information about the resonant characteristics and the spectral ratio of the surveyed buildings. The inevitable disadvantage of the use of microseisms is the small amplitudes of these seismic vibrations, which in principle does not allow to identify possible non-linear reactions of both the studied buildings and soils, which can origin, however, during strong earthquake occurrences. To a certain extent, especially for small size buildings, this defect can be compensated by using of the artificial vibration method. The paper compares the results of the application of the methods for analyzing the field of microseisms and the method of artificial vibration for a seismic assessment of a typical small private house. As a source of impact, a vibrator is used that simulates the impact on the entire surveyed house with an intensity I=VI, and on individual sites of the building - up to intensity I=IX. An sufficient agreement was obtained between the results of both methods in relation to the characteristics of the building. However, in the soil investigation woth using a vibrator, an additional low-frequency blurred maximum with a period of 0.3-0.7 sec was found, which, by the way, overlaps with the period of natural oscillations of the surveyed building in the E-W direction. The reason for an appearance of this additional low-frequency period of oscillations of the soil strates can be connected both with the resonance arising from the boundary located in the soil at a depth of 20-30 m, and with the beginning of the liquefaction of the soil. Based on the available data, we find no possibility to make a choice between these two possible explanations. The above comparisons point to the limited applicability of the methods based on the use of the microseisms. On the basis of the performed analysis, recommendations for choosing the orientation of new-constructing buildings of the studied type are proposed.
Keywords: artificial vibration, microseisms, soil properties, earthquake resistance, fundamental period.
Orunbaev Sagynbek Zholchuyevich – Master Researcher, Central Asian Institute of Applied Earth Sciences, Kyrgyzstan, 720027 Bishkek, ul. Timur Frunze 73/2. Tel .: + 996-312-555-111.
Fax: + 996-312-555-222. E-mail: s.orunbaev@caiag.kg
Mendekeyev Rayymkul Abdymananovich – Doctor of Technical Sciences, Director, Research Institute of Earthquake Engineering at the Kyrgyz State University of Construction, Transport and Architecture (KSUCTA). 720000, Bishkek city, Mildybaev str., 34b Tel .: + 996-772-47-48-98. E-mail: mra58@mail.ru
Moldobekov Bolot Duyshenalievich – Candidate of geological and mineralogical sciences, Director, Central Asian Institute of Applied Earth Sciences, Kyrgyz Republic, 720027 Bishkek, ul. Timur Frunze 73/2. Tel .: + 996-312-555-111. Fax: + 996-312-555-222. E-mail: b.moldobekov@caiag.kg
Rodkin Mikhail Vladimirovich – Doctor of physical and mathematical sciences, chief research officer, Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Russian Academy of Sciences. Russia, nstitute of Marine Geology and Geophysics, Far East Division, Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia 117997, Moscow, ul. Profsoyuznaya, 84/32. E-mail: rodkin@mitp.ru
Cite this article as: Orunbaev S.Z., Mendekeyev R.A., Moldobekov B.D., Rodkin M.V.. Microseismic and vibroseismic explorations of the house, results and comparison (on the example of a typical private residential house in Bishkek, Kyrgyzstan), Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology), 2018, Vol. 45, No. 1, pp. 49–58. [in Russian]. DOI: 10.21455/VIS2018.1-5
English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990), 2019, Volume 55, Issue 1.