Experimental Study on Consolidation-Creep Behavior of Subgrade Modified Soil in Seasonally Frozen Areas

Frost heaving and boiling are the most common road disorders due to the special climatic conditions in a seasonal frozen area. From the perspective of controlling road disorders in seasonally frozen areas and making effective use of industrial waste residue, two kinds of subgrade modified soil—crumb rubber modified fly ash soil (CRFS) and oil shale waste residue modified fly ash soil (OSFS)—were proposed by the research group. The research results proved that the two new subgrade fillers both have excellent engineering characteristics in cold areas, such as high strength and low thermal conductivity, and both have the function of waste utilization, giving them broad application prospects. In road engineering, the instability of slopes and retaining walls and the uneven settlement of the subgrade are closely related to soil creep, which are problems that cannot be ignored in road design and use. As a new material to treat road disorders in seasonally frozen areas, more attention should be paid to the continuous deformation property of modified soil under long-term load. The study on the creep characteristics of the modified soil can provide reliable parameters for the design of the modified soil subgrade and predict the settlement of the subgrade after construction, which is of great significance to the stability of the subgrade. In this paper, an experimental study on the consolidation–creep characteristics of two kinds of subgrade modified soil in a seasonal frozen region was carried out, the relationship between modified soil deformation and time is discussed, and the effects of different moisture contents and compaction degrees on the creep characteristics of modified soil were analyzed. The test results provide parameters for the engineering design of modified soil subgrade and provide data support for the popularization and application of modified soil in seasonally frozen subgrade.