Test method and application for microstructures of undisturbed silty sand and sandy silt
- 157 Downloads
The physical and mechanical properties of soil are determined by microstructure. Sandy silt, silty sand and other weak cohesive materials have low strength in the dry state, limiting the apply scope of scanning electron microscope and mercury porosimeter in such material. The experiment proposes the use of solid–liquid–gas three-phase transformation principle of menthol to strengthen the soil particle, include related sampling device and experimental procedures, to obtain parameters of the microscope image and porosity characteristics. Scanning electron microscopy show the clear photograph of particle form, spatial position, contact mode, plane pore characteristics and so on for undisturbed silty sand and sandy silt in Shanghai area. Freeze–thaw action can change the micro-pore parameters of soil. The mercury intrusion porosimetry test demonstrates that the pore volume, accumulated pore area, the most probable pore size and appearance probability of frozen-thawed silty sand increase with the decrease of freezing temperature. The pore size shows a normal distribution. Besides, pore size distribution of frozen-thawed sandy silt shows the interval distribution. Increasing the freezing temperature, the pore volume and accumulated pore area for sandy silt increase, while bigger value and smaller probability of the most probable pore diameter are obtained.
KeywordsMicrostructure Silty sand Sandy silt Scanning electron microscopy Pore size distribution
This work was supported by the National Natural Science Foundation of China (Grant no. 41572285).
- Chamberlain EJ (1981) Frost susceptibility of soil, review of index tests. In: Army cold regions research and engineering laboratory. Monograph, pp 81–82Google Scholar
- Ding Z, Zhang M, Wei X et al (2016) Study on pore pressure and microstructure of frozen and thawed soft soil under subway cyclic loading. Chin J Undergr Space Eng 35(11):2328–2336 (in chinese) Google Scholar
- Fang J, Zhang Z, Zhang J (2009) Application of artificial freezing to recovering a collapsed tunnel in Shanghai metro No. 4 line. China Civil Eng 42(8):124–128 (in Chinese) Google Scholar
- He L (2009) Experimental study on electrical resistivity characteristic of silty clay under uniaxial compression and frozen-thaw cycles. Graduate School of Chinese Academy of Science, Wuhan (in Chinese) Google Scholar
- Kong L, Huang H, Zhang D (2007) Experiment study on relationship between pore distribution and different stress levels due to consolidation of soft clays. Chin J Undergr Space Eng 3(06):1036–1040 (in Chinese) Google Scholar
- Shear DL, Olsen HW, Nelson KR (1993) Effects of desiccation on the hydraulic conductivity versus void ratio relationship for natural clay. National Academy Press, Washington, DC, pp 1365–1370Google Scholar
- Shi B (1997) A simple quantitative analysis method for microstructure of clayey soil. Hydrogeol Eng Geol 20(6):7–10 (in Chinese) Google Scholar
- Wang Q, Sang W, Xu L (2011) Fractal geometry of consolidation settlement of soft soil based on simulation experiment. J Jilin Univ 41(2):465–470Google Scholar