Effect of environmental factors on mechanical properties and damage characteristics of mine overburden used in subgrade

ABSTRACT

The resource utilisation of mine overburden in subgrade is an essential approach to accelerate environmental governance in mining areas. The present study focuses on investigating the mechanical properties and damage evolution of mine overburden under different environmental factors. The influences of water immersion, freeze–thaw cycles, water and salt migration on the road characteristics of mine overburden with different coarse grain contents (CGCs) were systematically studied and a cumulative damage model of mine overburden was proposed. The durability of mine overburden under the effect of the environmental factors was further compared. The results showed that mine overburden has less frost heave and can be utilised as subgrade filler in seasonally frozen region. With the increase of CGC of mine overburden, the resilient modulus and CBR gradually increase, and the UCS increases first and then decreases. The cumulative damage model of mechanical properties can effectively characterise the failure evolution of mine overburden. The infiltration of sulphate solution turns the mine overburden filler into weak frost heaving soil. The mine overburden with a CGC of 40% – 60% can be selected to improve the environmental adaptation. The wrapping method is recommended to reduce the impact of negative temperature and moisture on mine overburden subgrade.

KEYWORDS:

• Mine overburden
• subgrade
• environmental factors
• water immersion
• freeze-thaw cycles
• water and salt migration
• damage evolution

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Transportation Department Science and Technology Project in Ministry of Transport of the People's Republic of China: [Grant Number 2019-MS1-024]; Fundamental Research Funds for the Central Universities, CHD: [Grant Number 300102210705,300102219314]; Shaanxi Province Key Research & Development Plan: [Grant Number 2021GY-206]; Transportation Department Science and Technology Project in Xinjiang Uygur Autonomous Region of China: [Grant Number 2019-ZD1-015].