РАБОТА ВИНТОВЫХ СВАЙ В МЁРЗЛЫХ ГРУНТАХ

• Main Authors: АКСЁНОВ ВИКТОР ИВАНОВИЧ, ГЕВОРКЯН СЕРГЕЙ ГЕОРГИЕВИЧ, ИОСПА АНДРЕЙ ВИКТОРОВИЧ, КРИВОВ ДЕНИС НИКОЛАЕВИЧ, ШМЕЛЁВ ИГОРЬ ВЛАДИМИРОВИЧ
• Format: Text
• Language: unknown
• Published: Автономная некоммерческая организация Научно-издательский Центр "Пространство и Время" 2016
• Subjects: ВИНТОВЫЕ СВАИ,МЁРЗЛЫЕ ГРУНТЫ,ФИЗИЧЕСКОЕ МОДЕЛИРОВАНИЕ,СДВИГ,СЖАТИЕ,СМЕРЗАНИЕ,СТРОИТЕЛЬСТВО В КРИОЛИТОЗОНЕ,SCREW PILES,FROZEN SOIL,PHYSICAL MODELING,SHEAR,COMPRESSION,FREEZING,CONSTRUCTION IN PERMAFROST; The Heel; permafrost
• Online Access: http://cyberleninka.ru/article/n/rabota-vintovyh-svay-v-myorzlyh-gruntah; http://cyberleninka.ru/article_covers/16794666.png

В статье приводятся результаты лабораторных исследований на физических моделях работы винтовых свай в мёрзлых грунтах, проведённых в целях получения представлений о работе винтовых свай в натурных условиях. Использование морозильных камер и специально изготовленного оборудования (модели сваек, силовая установка, средства измерения и т.п.) позволили успешно решить задачу по физическому моделированию работы винтовых свай в мёрзлых грунтах. Полученные результаты позволили уточнить методику расчета работы винтовых свай в мерзлых грунтах и предложить новую расчетную формулу, особенность которой состоит в том, что она не учитывает смерзание цилиндрической части сваи с грунтом. Анализ результатов испытаний натурных винтовых свай, доведенных до срыва, показал практическую приемлемость предложенной расчетной формулы. There are various methods of pile foundations, as by way of devices and by design features. According to the method of device, piles may be hammered, screwed, drill-hammered, drill-injected. Depending on the material, piles may be concrete or metal. Depending on their design features, piles may be smooth, with extended fifth, with the broadening along the entire length, and screw. Currently screw piles are widely used in the areas of distribution of snowmelt and frozen soils, in various fields of construction. Screw pile is a cylindrical pile with helical projections (lobes) at its lower end. Screw piles are a relatively new but promising design for their application in the territories of the permafrost. They have a number of significant advantages compared to conventional prismatic and cylindrical hanging piles and piles-racks: (i) universality for the different soils; (ii) greater speed of construction of foundations in difficult climatic and cramped conditions; (iii) successful operation under alternating loads, and also in conditions of frost heaving of soils; (iv) high accuracy of the installation; (v) bumpless immersion in the soil, ensuring the safety of underground utilities and surface structures, etc.; (vi) absence of wet processes in the production of works. In our paper, we discuss the results of laboratory researches on physical models of the work of screw piles into frozen soils. The aim of our study was obtaining results of experiments with models to get the necessary answers to questions about the work of screw piles in natural conditions. The use of freezers and specially made equipment (model screw piles, the test facility, measurement tools, etc.) allowed us to solve successfully the problem on physical modeling of work of screw piles into frozen soils. The results of these tests show that under other equal conditions (composition of the soil, moisture, density, etc.) wherein the length of the ‘feathered’ parts of the screw piles increase 2 times, in this case carrying capacity of screw piles increases of approximately 40÷50%. Analysis of the curves describing soil deformation under pressing model screw piles showed that deformation of frozen soil grows exponentially during the stress application to the screw pile load by the equal degrees. This means that frozen soil behaves like Voigt’s environment during the interaction with screw pile. A characteristic feature of the Voigt’s environment is that developing it under the action of compression stresses the total deformation ε has two components: deformation of compression and deformation of viscous flow. The results of our research have confirmed the fact of formation of the compacted soil cores under the heel of the screw piles. Accounting compressed kernel allows you to calculate the surface area of the shift during the definition of bearing ability of screw piles. The results of our study helped to clarify the methods of calculating the work of screw piles into frozen soils and to offer a new calculation formula. The distinctive feature of this formula is that it does not take account the freezing of the cylindrical part of the pile with the ground. Analysis of the results of field tests of full-scale screw piles driven to collapse, showed practical acceptability of the proposed formula.