Ageing deformation of tailings dams in seasonally frozen soil areas under freeze-thaw cycles

Jiaxu Jin,Xinlei Zhang,Shiwang Li,Xiangfeng Lv,Chenguang Song

doi:10.1038/s41598-019-51449-6

Abstract

The freeze-thaw cycle is one of the important factors in inducing a dam-break in the permafrost region, so it is of great practical significance to study the mechanism of the failure deformation of tailings dams under freeze-thaw cycles. In this paper, the water-heat-force coupling model of a tailings dam considering frost-thaw damage is established, and the freeze-thaw cyclic ageing deformation of a tailings dam in a seasonally frozen soil area is studied. The correctness of the model is validated by numerical calculation. The research shows under the same water content, the compressive strength and modulus of deformation decrease with an increase in the number of freeze-thaw cycles, the cohesion and internal friction angle decrease, and the amplitude gradually decreases before becoming stable. In the process of cooling, the pore water pressure first increases and then decreases, and the pore water pressure first decreases and then increases during the heating process. The research results can provide a theoretical basis and reference values for the stability analysis of tailings dams in seasonally frozen soil areas.

Highlights

The freeze-thaw cycle is one of the important factors in inducing a dam-break in the permafrost region, so it is of great practical significance to study the mechanism of the failure deformation of tailings dams under freeze-thaw cycles
The slope of a tailings dam in a seasonally frozen soil area is affected by natural freezing and thawing, which damages the structure of the tailings sand and decays the mechanical properties[1,2]
The stability evaluation of the tailings dam in cold areas and the prevention and management of freeze-thaw disasters are key scientific problems[9,10]. It is of great theoretical and engineering significance to study the ageing deformation of tailings dams in seasonal permafrost areas under the action of freeze-thaw cycles, which is the basic mechanical problem directly facing the construction of tailings reservoirs in cold areas

Summary

Introduction

The freeze-thaw cycle is one of the important factors in inducing a dam-break in the permafrost region, so it is of great practical significance to study the mechanism of the failure deformation of tailings dams under freeze-thaw cycles. By setting up a separate open and sealed test environment, the environmental response of the specimen to the surface crack, water content, shear strength, cohesion and internal friction angle after different freeze-thaw cycles was studied by Ai et al.[18], and the response of the mechanical properties to the environment was obtained via the mathematical fitting function. These studies mostly involve the change law of the basic mechanical characteristics of tailings sand, but there is less research on the deformation and internal force evolution law of tailings dams under the freeze-thaw cycles. The research results can provide a basis for the safe operation of a tailings dam in seasonally frozen soil areas

Methods

Findings

Conclusion