Abstract
Based on the current shortcomings in frozen wall designations, in which the unconfined compressive strength test parameters of undisturbed and remolded frozen soils are used for calculations, in situ frozen soil samples were taken from a frozen wellbore, and unconfined compressive strength tests were performed in this study. The test results showed significant discreteness in the in situ freezing uniaxial compressive strength of the cohesive soil, with low test repeatability. Because of the anisotropy of the original soil structure, the elastic modulus of 31.3% of the undisturbed frozen soil was found to be lower than that of the remolded frozen soil at the same temperature, and it was 0.5–2.1 times the elastic modulus of the remolded frozen soil. This value was negatively correlated with the freezing temperature; however, it had no evident relationship with the occurrence depth of the frozen soil. Based on the design principle of the frozen wall of the west air shaft in Zhaogu No. 2 Mine, the thickness calculated by substituting the in situ frozen soil test parameters was 1.14–1.61 times that of the original design of the frozen wall of the viscous soil layer.
Highlights
The artificial ground freezing (AGF) method is a construction method developed on the basis of seasonal frozen soil
-10°C: A3 > A2 > A1 > A4 -15°C: A2 > A1 > A3 > A4 -20°C: A2 > A1 > A3 > A4 -25°C: A1 > A2 > A4 > A3 The results show that under the condition of no confining pressure, the temperature of the undisturbed frozen soil and remolded frozen soil is negatively correlated with the uniaxial compressive strength, and the uniaxial compressive strength of the remolded frozen soil shows similar properties
In this study, unconfined compressive strength tests were conducted on frozen soil sampled from Zhaogu No 2 Mine under undisturbed and remolded conditions
Summary
Frozen soil is a type of special rock/soil composed of four basic components: solid particles, ice, liquid water, and gas. When the mechanical parameters of a remolded frozen soil are applied in the design of natural foundations or frozen walls in the original state, the calculation results are biased, and it should be modified in practical applications [8–10]. The conservation of undisturbed frozen soil, which is obtained from the drilling hole, is a process of water migration at low temperatures under the condition of the original moisture content, and ice lenses are formed at the contact end of the cold source [14–18]. The existing frozen soil test is generally based on sampling from the wellbore inspection hole In this case, the test results cannot fully reflect the real original characteristics of the frozen soil; a frozen soil “block” taken from inside the wellbore is in a good original state, and the migration and redistribution process of most of the free water would have been completed. By comparing with the original design parameters, the influence degree of the different sampling methods on the design calculation results of the frozen wall thickness was analyzed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
