Experimental Study On Mechanical Properties Of Reinforced Calcareous Sand And Its Application In Retaining Wall

In recent years,calcareous sand,a material that differs greatly from continental sediments in the mechanical properties,has gradually attracted people’s attention.In addition,geosynthetic reinforced soil structures has gained extensive applications in engineering,however,people still do not have a clear understanding of the mechanical properties of reinforced calcareous sand,whether it can be used in reinforced retaining wall engineering also lack of a reasonable understanding.This thesis takes reinforced calcareous sand as the research object,analyzes the characteristics of strength,deformation and particle breakage of reinforced calcareous sand through a series of triaxial compression tests,and analyzes the reinforcement mechanism of reinforced calcareous sand by simulating the triaxial test.Finally,through numerical simulation analysis,the feasibility of using calcareous sand as a filler for reinforced earth retaining wall was discussed and to analyze the reinforced calcareous sand retaining wall working characteristics under various working conditions.The main research methods and results are as follows:(1)In order to study the mechanical properties of reinforced calcareous sand,through a series of triaxial tests,the stress-strain relationships of calcareous sand in different reinforcing materials,with different reinforced layers and different confining pressures was obtained.The results showed that,compared with calcareous sand,the strength after reinforcement was significantly improved,and increased with the number of reinforcement layers,and the reinforcement effect was better under low confining pressure.(2)Reinforcement enhanced the particle breakage of calcareous sand,and the particle breakage of reinforced calcareous sand was affected by many factors such as confining pressure,number of reinforced layers,and reinforced materials.Under low confining pressure,the particle breakage of reinforced calcareous sand was mainly reflected in the fracture and shear of some particle corners,adding a very small amount of fine-grained components.Under high confining pressure,it was mainly reflected in the proportion of medium and fine particles obviously increase.There existed a certain relationship between the energy consumed by reinforced calcareous sand and particle breakage.(3)In order to understand the reinforcement mechanism of reinforced calcareous sand,the strength of the reinforced soil interface was obtained through simulation of the triaxial tests.The increase in strength after reinforcement was mainly due to the frictional resistance generated between the interface between calcareous sand and the reinforcement,which restricted its lateral deformation.The equivalent confining pressure mechanism could be used to explain the strength increase of reinforced calcareous sand.The failure mode of reinforced calcareous sand was mainly frictional failure.(4)From the perspective of deformation and stability,the working performance of reinforced calcareous sand and siliceous sand retaining wall was compared and analyzed.At the same time,the influence of step width and number of reinforced layers on the performance of reinforced calcareous sand retaining wall was analyzed.