The Microstructure Characters of Saline Soil in Qarhan Salt Lake Area and Its Behaviors of Mechanics and Compressive Strength

Abstract

In order to verify the microstructure of saline soil in Qarhan Salt Lake area and its behaviors of mechanics and compressive strength, nine-group saline soil samples with different salt content were collected from the Qarhan Salt Lake and the microstructure of samples was scanned by electron microscope. Direct shear test and compression test were made accordingly. The behaviors of mechanics and compressive strength of saline soil were analyzed from the microstructure. The paper puts forward the skeleton connecting forms between particles of saline soil and took its results in comparison with the studies of Xinjiang plate-like saline soil. The study results show that: (1) The link of soil particles have three forms: ① point contact; ② stacked contact; ③ salt crystals cementation. (2) Saline soil with different salt content has different microstructure. The more dense the microstructure is, the stronger the salt crystals cement, and saline soils show higher mechanical and strength characteristics. Salt crystals cementation is the significant factor which affects the saline soil mechanics and strength characteristics. (3) Unconfined compressive strength significantly changes when salinity reaches and exceeds 45.74 %. (4) Compared with Xinjiang plate-like saline soil, as the difference of grain grade, with the increase in salt content, the microstructure and strength changes are different between the saline soils in Qinghai Qarhan Salt lake and Xinjiang province.