Experimental Investigation on Frost Heaving Force (FHF) Evolution in Preflawed Rocks Exposed to Cyclic Freeze-Thaw Conditions

Abstract

This work is aimed at investigating the structural deterioration and the frost heaving force evolution characteristics of flawed rocks using a self-developed frost heaving force (FHF) measurement system. Three kinds of preflawed rocks with different flaw geometry parameters were used to conduct the FHF measurement tests. The testing results reveal five distinguished stages from the frost heaving force evolution curve; they are the inoculation stage, explosive stage, decline to steady stage, recovery stage, and sudden drop stage. In addition, a secondary frost heaving phenomenon is found, and the secondary peak value is lower than the initial peak value. Moreover, the FHF decreases with increasing the F-T cycle number, and its decreasing rate becomes faster at a high F-T cycle. The frost heaving force is affected not only by flaw geometry but also by the lithology. For low-pore hard rock, damage propagates quickly after the occurrence of freeze-thaw damage. It is suggested that the mesoscopic structure of rock affects the water migration and water-ice phase transformation, and rock can be fractured by FHF in the preexisting flaws.

Frost heaving damage mechanism of fractured rock masses: Main research progress and prospects for international frontiers

“…In addition to external factors, the lithology, structure, and cement of FRM have a very significant influence on frost heaving weathering. The lithology determines the water migration capacity, affects the water-ice phase transition, and is a decisive factor affecting the frost heaving force [49] . Frost heaving force causes the weaker cemented particles in rock to dislodge, resulting in more pores and storage of more water.…”

“…Frost heaving force causes the weaker cemented particles in rock to dislodge, resulting in more pores and storage of more water. Wang [49] pointed out that the order of influence on the frost heaving deterioration of FRM was: rock lithology > fracture width > cement > fracture length. Fig.…”

“…The area of permafrost frozen soil accounts for about 22.83% of the country's land area (about 2.19 million km 2 ), which is mainly distributed in the Qinghai-Tibetan Plateau, the Daxing'anling and Xiaoxing'anling regions, the Altai Mountains, the Tianshan Mountains, the Qilian Mountains, the Himalayas, and other mountainous regions. The area of seasonal frozen soil accounts for about 49.6% (about 4.76 million km 2 ) of the country's land area. The area of transient frozen soil is about 1.86 × 10 6 km 2 , accounting for 19.33% of the country's land area.…”

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

“…In the 1970s, Tenneco Oil Company proposed injecting cryogenic fluid into coal and rock fractures to increase natural gas production. − Industrial field tests were successfully conducted by B. W. McDaniel in 1997 and Steve R. Grundman in 1998 and proved that repeated fracturing using LN 2 can increase the production of unconventional oil and gas. − Between the late 1990s and the early 21st century, unconventional oil and gas production met demand from the energy market, and research on LN 2 fracturing stagnated. − In recent years, the share of unconventional oil and gas in global oil and gas production has continued to increase. As a result, LN 2 technology, fracturing mechanism, and influencing factors have once again become the focus of many research studies. − Liquid nitrogen fracturing has many advantages over traditional fracturing technologies.…”