Application of pile foundations in structurally unstable soils

Abstract

The active development of the Asia-Pacific region is often accompanied by geotechnical problems that require a rational solution. The article presents the results of a laboratory experiment that simulates the process of slurried pile construction in sandy frozen soils. The authors present the dependence of changes in the temperature of the soil and cement-sand mortar in time, defined the maximum radius of thawing and the total duration of the process of thawing and freezing back to the natural state, given the recommendations for the design of slurried piles taking into account thermal interaction with permafrost soils. The article presents a laboratory study of the interaction of auger cast piles with frozen soil. The results of laboratory studies of the strength of cement mortars of different compositions, hardened at a negative temperature. Recommendations on the choice of the solution composition for the installation of grout-injected piles in frozen soil are given. The article presents the state of the question of designing multi-blade screw piles, reflects the relevance of the development of methods of calculation and updating the regulatory framework. The authors carried out calculations of the bearing capacity of screw piles on various calculation schemes, the results of which are compared with field tests. As a result of comparison recommendations on the choice of the reliable settlement scheme are given. The authors believe that the solution of the problems identified in the article related to the use of advanced types of pile foundations in difficult geotechnical conditions will significantly improve the reliability of structures, reduce construction time and reduce economic costs.