Experimental Investigation of the Engineering Properties of Coarse Grain Embankment Fill Material with Accumulative Salt Effect by Adding Onsite Brine Groundwater

摘要

The purpose of this research is to study the accumulative effect of repetitively adding groundwater on the engineering properties of coarse grain salinized embankment fill material. Large-scale compression and engineering characteristics tests were carried out on different salt content samples. Based on the laboratory test results, the influence factors on the engineering properties were analyzed by repetitively adding groundwater with SO_4~(2-) or CL~-. With the increase of added water containing SO_4~(2-) or CL~-, the compressive deformation of tested samples showed a trend of dramatically increasing at the beginning followed by gradually decreasing, while the collapse deformation of the samples increased continuously. The coefficient of compressibility showed a typical three-stage variation law, regardless of the salt type of added water. With the decrease in temperature (simulating the cooling period during construction), the excess content of SO4" in the water resulted in an increase of salt expansion in the samples, while shrinkage behavior was observed with the excess of CL~ in the water. Thus, an obvious accumulative effect in the salt expansion of the sample was observed. With the increasing addition of water containing SO_4~(2-) or CL~-, the collapse deformation of the samples increased continuously. Moreover, the effects of added water with SO_4~(2-) or CL~- on the engineering characteristics of the samples were discussed from the following perspectives: salt accumulation, distribution of salt in the soil, interaction of salt ions, and dissolution of soluble salt. It is further shown that even a small amount of soluble salt in groundwater will have a significant impact on the engineering properties of the coarse grain saline soil with an accumulative effect by repetitively adding groundwater.