Study On Engineering Characteristics And Compaction Control Of Clay Soil With High Moisture Content Under Curing

Embankment projects are related to the national economy and people's livelihood,and are inseparable from the political,economic,and social development.In order to guarantee the quality of embankment construction,embankment fill must have sufficient impermeability,shear strength,and compression resistance.However,due to the uneven type and quality of the earth filling material along the dam,the poor engineering properties make it difficult to directly use the filling material for the embankment.For soil materials that do not meet engineering requirements,a method of curing and improving with different materials is adopted.In this paper,relying on the dam protection project of the Songhua River Basin in Heilongjiang Province,the experimental study on the performance of the groyne filling was carried out after systematically curing the clay with high moisture content.The main work and research results are as follows:The research history and status quo of curing agent used as clay modification are summarized.The basic mechanism of curing agent modification,curing theory and mineral characteristics of clay with high moisture content are summarized.Factors influencing the effect of curing are summarized:1.The research history and status quo of curing agent used as clay modification are summarized.The basic mechanism of curing agent modification and the mineral characteristics of clay with high moisture content are summarized.The factors affecting the curing effect are summarized.2.The relevant specification requirements for the use of high water content clay soils as embankment fillings are summarized.The basic characteristics of the clay soil with high water content in the Songhua River Basin were measured.It was concluded that the high water content clay soil in the Songhua River Basin did not meet the requirements of the levee packing standard,and the dehydration modification was required.3.The composite solidified material of cement + lime + fly ash + fine sand was selected.Through laboratory tests,the changes in properties such as strength,compaction,specific gravity,permeability coefficient,and moisture content in the curing process were measured,and different cured materials were evaluated.The dehydration cure effect reveals the main reason for the low curing efficiency in the later stage of the test,and analyzes the influence of curing age and compaction degree of the sample on the curing effect.4.The series of laboratory tests such as compaction,water immersion and freeze-thaw cycle were used to study the influence of the air volume rate Va on the compaction quality control of clay,the immersion stability of compacted clay,and the freeze-thaw cycles.The results show that:(1)When the same compaction energy,the air volume rate(Va)corresponding to the maximum dry density and the optimal moisture content obtained by different compaction types(heavy and light)is different;when the same compaction type The air volume rate values for different impact energy at maximum dry density are basically the same;(2)The length of submergence destruction of compacted clay increases with decreasing air volume rate,showing a distinct"three-stage" feature.And the critical values of air volume ratio of different compacted clays in three stages are close to each other;(3)The unconfined compressive strength attenuation coefficient Q of the compacted clay as a whole undergoes multiple freeze-thaw cycles increases with the air volume rate.Reduce;(4)Proposed that the air volume rate of clay embankment filling in cold regions should be controlled within 10%.5.The imperfection of compaction control index as the index of compaction is summarized,and the rationality and superiority of the air volume ratio as an additional index of compaction control of cohesive soil are analyzed.