粗颗粒盐渍土路用填料可用性指标研究

Experimental Studies of the Applicability Index of Coarse-Grained Salty Soil as an Embankment Filling

盐渍土盐胀的主要控制因素有土、水、盐、温、力.采用均匀设计方法,通过系列室内单次降温盐胀试验,研究了粗颗粒硫酸盐渍土的盐胀特性及其作为路基填料的可用性.结果表明:影响粗颗粒硫酸盐渍土盐胀量大小的主要控制因素是含盐量、含水率及初始干容重,且三个因素互为联系及彼此影响.上覆附加荷载对盐胀量大小具有很强的抑制作用,砾类盐渍土起胀含盐量约0.4%,砂类盐渍土起胀含盐量约为0.2%.盐胀活跃温度区间主要为5^-5℃,活跃温度区间主要控制因素是含水率;如果初始干容重较低,盐胀过程中会发生体缩现象.

In the laboratory test of coarse grain saline soil samples collected from Gansu province in China, the representative samples of coarse grain saline soil were selected for the experiments of salt expansion tests under different conditions. The factors which control the behaviors of salt expansion are soil, water, salt, temperature and pressure. In order to investigate the salt expansion behaviors and embankment filling usability in coarse grain saline soil regions, the salt expansion behaviors of sulfate salty gravel is mainly studied with a single salty expansion experiment and freezing experiment under different loads based on uniform design. In the paper, salty expansion experiments at different loads are done, the salt expansion of sulfate salty gravel, the salt expansion of sulfate salty sand and the salt expansion of sandy sulfate salty soil are mainly studied. The effect of small particles on the characteristics of coarse grain sulfate salty soil is also studied. On this foundation, using non--linear regression analysis, the salt expansion characteristics and influence factors of coarse grain sulfate salty soil are revealed. The test shows that the main factors which control the behaviors of salt expansion are salt, water and initial dry density. Overburden pressure can make salt expansion smaller. When the coarse grained sulfate salty soil contains 50% of finegrained soil, at 50 kPa of overburden pressure, with 0.93 compaction degree and appropriate water content, the minimum salt concentration of sulfate salty gravel is 0.4% and the minimum salt content Of sandy soil sulfate salty soil is 0.2 %. When the coarse-grained sulfate salty soil contains 15% of fine-grained soil, at 50 kPa overburden pressure, with 0.93 compaction degree and appropriate water content, the minimum salt content of sulfate salty sand is 0.2%. At 5 ℃--5℃, the salt expansion of sulfate salty gravel is larger. When initial dry density is low, this soil would be shrunk in a cooling process.