Experimental Study On The Physical Property And Strength Characteristics Of Red Soil In South Jiangxi

The red soil soften,its water content increase and aggregates and particle size reduce during the rainwater infiltration,laterization process and load.These result in red soil body strength reduction,uneven settlement and landslides and other engineering problems.At present,many studies on red soil in Hunan,Guangxi and Guizhou has been done.But little research on the Gannan red soil has been done.The red soil characteristics are different due to the different of mother rock,weathering,transported deposit.Therefore,this paper takes the remolded laterite of a construction site in southern Jiangxi as the research object.The influence of particle size and water content on the physical and mechanical properties of Ganan red soil during laterization and under load was studied.The distribution of aggregate size of soil samples with different particle sizes was analyzed.The fractal dimension of aggregates with different particle sizes is calculated,and the relationship between fractal dimension and strength parameters is established.The influence of water content,particle size and grain grading on the red soil strength were analyzed using Coulomb strength theory.The main conclusions as follows:(1)When the particle size was 0~0.5 mm,the liquid limit and plastic limit of red soil decreased rapidly with the increase of particle size;when the particle size was 0.5mm~2 mm,the liquid limit and plastic limit of red soil decreased slowly and tended to be stable.This was mainly due to the increase of the specific surface area of the small particle size,the enhancement of the adsorption capacity of the combined water.So liquid plastic limit changed obviously.(2)When the particle size was less than 0.5 mm,with the increase of the particle size,the NMWD value increased from 0.58 to 1.05,the stability of aggregates was better;when the particle size was greater than 0.5mm,with the increase of the particle size,the NMWD value decreased from 1.05 to 0.94,the stability of aggregates was worse.(3)When the particle size of red soil was 0.075~0.25 mm,0.25~0.5 mm and the original gradation,with the increase of water content,the cohesion of red soil first increased and then decreased,and reached the maximum value when the water content was about 18%;when the particle size of red soil was 0.5~1 mm,with the increase of water content,the cohesion of red soil gradually decreased.(4)With the increase of particle size,the cohesion of saturated red soil decreased first,then increased and then decreased,and the internal friction angle of saturated red soil increased first,then decreased and then increased.When the particle size was0.25~0.5 mm,the cohesion and internal friction angle of saturated red soil reached the minimum and maximum values respectively.