Abstract

The article investigates dependences of flat ice strength properties in the Kara, Laptev and East Siberian seas on ice structure and physical parameters (first of all, on the ice temperature). Research was based on the array of experimental data on the flat ice properties studied during 2013-2017 expeditions in the Kara, Laptev and East Siberian seas and 2016-2019 work on the research site in the Khatanga bay of the Laptev sea. Analysis of various ice strength characteristics showed similarity of ice in the Russian Arctic seas and in the Pacific Ocean. The differences in the ice strength properties at different loading rates were determined, and the variation coefficients of ice strength parameters were estimated. Dependences on ice temperature were obtained for all ice strength characteristics, and show a good approximation that can be described by a linear law. Indenter and compressive strength correlations were reformed for various types of first-year ice. Regression equations were determined in order to estimate the bending strength of ice consoles; anomalous behavior of Young's modulus of ice was observed during tests of consoles. Results of the work can be used for calculating ice loads on offshore structures, as well as for assessing icebreaking capacity of vessels passing the Northern Sea Route.

Introduction

Information on flat ice strength properties is essential for assessment of ice loads on vessels hulls and offshore facilities. It can be obtained either during large-scale field studies across the seas or at a special ice research site. Each of these methods has advantages and disadvantages. Expeditionary surveys accumulate significant statistics on ice properties, but are time-limited to 1-2 months (mostly by economic factors). At research site it is possible to study ice for 7-8 months, but in one geographical location; only one type of ice can be studied. For a high-quality numerical assessment of the flat ice strength properties under various environmental conditions, a combination of both these methods is required. At the same time, there is an important scientific problem – to achieve a trustful correlation between expeditionary results obtained with icebreaker and site results. In 2013-2015 and 2017 authors carried out expeditionary ice studies in the Kara, Laptev and East Siberian seas. During 2016-2019 ice studies were conducted at the research sites "Khastyr" (Khatanga Bay of the Laptev sea), "Baranova Cape" (Severnaya Zemlya archipelago, Kara sea) and "Nogliki" (Sakhalin island, sea of Okhotsk). Locations of the studied ice stations (1-2 days each) and ice research sites of continuous ice study are shown in Figure 1. Detailed description of these works can be found in the articles (Kovalev et al., 2019) and (Bekker et al., 2020). This paper is focused on the study of combined data and on development of adequate correlations for the Arctic ice. The main goal of the work is to determine the sea ice strength as a function of its temperature and salinity.

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