Study On The Engineering Characteristics Of Guilin Clay Modified By Sand And Lime

As a world-famous tourist city,Guilin is building more and more infrastructure,especially the construction of highways and railways and so on.In order to improve the engineering problems of red clay in Guilin area as roadbed filler.In this paper,Guilin red clay is taken as the research object.Under the different curing age and different lime and sand content,the physical and mechanical properties of the red clay of Guilin and its influence mechanism are discussed by the liquid plastic limit,compaction,shrinkage and expansion,direct shear,consolidation and unconfined compressive strength test.The main results are as follows:(1)When lime is added alone,the liquid limit of red clay will be reduced,while the plastic limit will basically remain unchanged,reducing the optimum moisture content and the maximum dry density.However,when the ash content reaches 4%,the liquid plastic limit of red clay will remain unchanged with the increase of lime content.The addition of sand alone will reduce the liquid plastic limit,the optimal moisture content and the maximum dry density of the red clay in Guilin.At the same time,when adding sand and lime,the liquid plastic limit and optimal moisture content of Guilin red clay will be reduced,and the maximum dry density will be raised.(2)When lime and sand mixed with lime and sand alone,both shrinkage and swelling properties of red clay are effectively reduced.Considering the lime addition,it is suggested that the ash mixing rate should not exceed 4%.At the same time,when the sand and lime were mixed,the shrinkage and shrinkage coefficient decreased obviously.The minimum value appeared in the red clay with 12% lime content and 35% sand content.(3)Lime and clay can increase the cohesion and internal friction angle of red clay.In the later stage of maintenance,with the increase of lime content,the cohesion of red clay first increased and then decreased,and the internal friction angle increased first and then stabilized.When curing for 28 days,the cohesive force of red clay with 8% lime content is the largest,which is 4.83 times that of plain soil.When lime and sand are mixed with lime and sand,the cohesive force and internal friction angle of red clay increase with the increase of curing age.At 28 days of maintenance,the cohesion of the red clay with 8% lime content of 15% sand is the largest,which is 4.83 times of the plain soil.The internal friction angle of the red clay with 8% lime content and 35% sand content is the largest,which is 2.06 times that of the plain soil.(4)When lime is added alone,the compression coefficient of red clay decreases with the increase of curing age,while the compression modulus is just the opposite.When curing for 28 days,the compression coefficient of the 8% lime content red clay is reduced to a minimum,and the range of reduction is 68.4% to 71.37%.When the sand is added alone,the compression coefficient of red clay decreases first and then increases with the increase of sand mixing rate.The minimum compression coefficient is 25% sand mixed with red clay.At the same time,when adding lime and sand,the compression coefficient of red clay decreases with the increase of curing age,the minimum compression coefficient is 28 days,and 12% lime is mixed with 35% sand.(5)When lime is added alone,the unconfined compressive strength of red clay increases with the increase of curing age.When the curing period is certain,the unconfined compressive strength of lime red clay increases with the increase of ash content,and the maximum value is 12% red clay for 28 days of curing.At the same time,when lime and sand were added,the unconfined compressive strength of red clay increased with the increase of curing age.