Mechanical properties of frozen soil (in Japanese with English summary)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenhua Yin ◽  
Hu Zhang ◽  
Jianming Zhang ◽  
Mingtang Chai

Abstract The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.


2014 ◽  
Vol 905 ◽  
pp. 230-234
Author(s):  
Jun Lei Tian ◽  
Yan Ke Yang ◽  
Yi Ping Hu ◽  
Jian Qiang Cheng

Ha Tai railway passenger dedicated line is a national key project of the eleventh five-year plan. Its different from other construction of high-speed railway because there is many frozen soil over the place. The requirement of the subgrade material is higher.We proposed a idea that gradred broken stone mixed with cement and fine powder applied in the project.The compressive strength,splitting tensile strength and flexural strength were studied and analyzed through laboratory test.And regression analysis between compressive strength and flexural strength was made .According to the regression analysis,a power exponent function between flexural strength and compressive strength was got.Based on this,the corresponding relationship table was deduced,which can be used in practical projects.


2013 ◽  
Vol 353-356 ◽  
pp. 1662-1665 ◽  
Author(s):  
Xiang Dong Hu ◽  
Yan Guang Han

Artificial ground freezing method (AGF) was applied in cross passage constructing of line 1 and 2 of Wuxi Metro. Mechanical properties of frozen soils such as uniaxial compressive strength, modulus of elasticity, Poissons Ratio, frost heave rate and freezing point are prerequisite for design and construction of AGF. In order to obtain the parameters mentioned, laboratory tests were conducted. One was the basic geotechnical test. Another was the frozen soil test.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Lingshi An ◽  
Xianzhang Ling ◽  
Yongchang Geng ◽  
Qionglin Li ◽  
Feng Zhang

Although frozen soil is in nature the discrete material, it is generally treated as the continuum material. The mechanical properties of frozen soil are so complex to describe adequately by conventional continuum mechanics method. In this study, the nonlinear microcontact model incorporating rolling resistance is proposed to investigate the particle-scale mechanical properties of frozen soil. The failure mechanism of frozen soil is explicated based on the evolution of contact force chains and propagation of microcracks. In addition, the effects of contact stiffness ratio and friction coefficient on stress-strain curve and energy evolution are evaluated. The results show that the nonlinear microcontact model incorporating rolling resistance can better describe the experimental data. At a higher axial strain, the contact force chains near shear band which can give rise to the soil arch effect rotate away from the shear band inclination but not so much as to become perpendicular to it. The propagation of microcracks can be divided into two phases. The stress-strain curve is strongly influenced by contact stiffness ratio. In addition, friction coefficient does not significantly affect the initial tangential modulus. Compared with frictional coefficient, the effect of contact stiffness ratio on stress-strain curve and energy evolution is greater.


2012 ◽  
Vol 442 ◽  
pp. 286-290
Author(s):  
Gui Quan Bi

Loess foundations in seasonally frozen soil region are subject to severe effect of freeze-thaw cycles. This often results in water redistribution and structure weakening. So it is very important to study the physical-mechanical properties of loess under freeze-thaw cycles. In this paper, systematic study was carried out using freeze-thaw cycle machine. The impacts of freeze-thaw cycles on the physical-mechanical properties of loess including deformation, water distribution and dry density under the condition of filling water to loess samples were investigated. The results proved that the freeze-thaw cycles can increase the water content gradually from the bottom to the top in the loess samples under water supplied condition. The water content gradient reaches maximum at the freeze-thaw interface. The loess samples deform sharply at the early stage of the freeze-thaw cycles and then reach a stable status. The freeze-thaw cycles decrease the dry density of the loess samples gradually. The dry density at the top is lower than that at the bottom, due to more severe freeze-thaw effect at the top of the samples.


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