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Singapore has a relatively high water table. When liquefied natural gas (LNG) storage systems are built in soils below the water table in Singapore, the engineering properties of the surrounding soils could be improved through cement stabilization. Due to the extremely low temperature (T) of LNG (approximately −162°C), the effect of ultralow T on the physical and mechanical properties of cement-stabilized soil in case of accidental LNG leakage should be investigated. However, existing studies on cement-stabilized soils are limited to T above −20°C. Therefore, in this study laboratory experiments to quantify volumetric expansion, unconfined compressive strength (UCS), and Young's modulus (E) of cement-stabilized soils at −40°C, −80°C, and −120°C were conducted. The experimental results indicated that the stabilized soils' volumetric expansion reached ≤2.6% at −120°C. The UCS and E of the stabilized soils increased from 0.9 to 27.6 MPa and from 99.8 to 2,669 MPa, respectively, and the T decreased from 24°C to −120°C. In summary, the ultralow T induced limited volumetric expansion (<3%) for cement-stabilized soil and significantly increased its strength and E, which indicated that cement soil stabilization could be beneficial for underground LNG storage systems in Singapore when exposed to accidental LNG leakage. [ABSTRACT FROM AUTHOR]

Frost heave of soil is a highly nonuniform problem, in which the local deformation is much more severe and meaningful compared with the overall deformation. When soil is upon freezing, a water–ice phase change occurs and induces the migration of pore water. Subsequently, the distribution of temperature, water content, ice content, and fabric is highly nonuniform in frozen soil. The local frost deformation of soil mainly depends on the local temperature, soil water content, and ice content. In this study, the particle image velocimetry (PIV) method is introduced into the soil column test to monitor the local frost deformation. Several tracer particles are tested to overcome the difficulty that the deformation field is not clear in clay soil. The results demonstrate that the mixed sand is a suitable choice of tracer particles and can lead to clear contours of vertical displacement and strain. Such local deformation information is valuable and can be synthetically analyzed with the local temperature, soil water content, and ice content. The PIV technique is considered to be a good choice for monitoring the local frost deformation field in frozen soil. [ABSTRACT FROM AUTHOR]