Effect of freeze–thaw cycle on physical and mechanical properties and damage characteristics of sandstone

Abstract

Rock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.

Study on the Influence of Saturation on Freeze–Thaw Damage Characteristics of Sandstone

“…The existing research has shown that the compressive strength, elastic modulus, Poisson’s ratio, and other mechanical properties of rock gradually decrease with the increase in the water content of rock in the process of freeze–thaw cycle [ 6 , 7 ], Hou et al [ 8 ] found that the water chemical softening mechanism plays an important role in the process of rock freeze–thaw damage. Ren et al [ 9 ] studied the change in mechanical properties and damage mechanism of saturated red sandstone under freeze–thaw and triaxial load.…”

Grouting technology and construction schemes of a tunnel in aeolian stratum: a case study of Shenmu No. 1 tunnel

“…Many studies have been conducted on this worldwide 16 – 19 . Jin et al adopted a pipe shed advanced support and observed that as the effective range of the one-time support increases, the integrity of the support increases and safety of the construction process increases 20 .…”

Investigation of the support constraint effect and failure instability law of tunnels constructed using the New Austrian tunneling method

“…Confinement convergence method and support constraint effect. During underground tunnel construction, the working face has a constraint effect on the surrounding rock after excavation, which gradually weakens as the working face advances and the surrounding rock pressure is slowly released 20,21 . Similar to the constraint effect of the working face, the support structure applied in a tunnel also has a certain constraint effect on the surrounding rock in front of it, which restricts surrounding rock deformation and is herein referred to as the "support constraint effect".…”