Experimental Study On The Mechanical Properties Of Wave-shape Fiber Reinforced Soil And Reinforced Soil Slope Model

Fiber reinforcement is a new type of soil improvement technology in recent years,which can effectively improve the engineering mechanical properties of soil.In this paper,a new wave-shape fiber is developed,and in order to study the mechanical characteristics and reinforcement mechanism of wave-shape fiber reinforced soil,a series of laboratory tests are carried out,including single fiber pull-out test,tensile test,unconfined compressive strength test and CBR test of wave-shape fiber reinforced soil,interfacial shear strength,tensile strength,unconfined compressive strength and bearing capacity of wave-shape fiber reinforced soil is systematicly analyzed.Through wave-shape fiber reinforced soil scanning electron microscope test,the reinforced mechanism and interfacial mechanics are slao analyzed by the microscopic point of view.In addition,based on fiber-optic sensing technology,fiber reinforced soil slope model test is carried out,and the influence of fiber on the stability of the slope is explored.In this paper,the mechanical properties of wave-shape fiber and straight fiber reinforced soil are compared with,and the qualitative and quantitative analysis are compared with,and the macro and micro analysis are relatied,test and simulation are compared with,and the main conclusions are as follows:(1)Interfacial shear strength of wave-shape fiber reinforced soil was quantitatively measured by conducting single fiber pull-out tests,analyzing mechanical characteristics on the interface of wave-shape fiber and soil,discussing the effect of water content,dry density,lime,cement on interfacial shear strength of wave-shape fiber reinforced soil.The result shows that:the pull-out curve of wave-shape fiber reinforced soil show typical multi-peaks,and compared to traditional straight fiber,wave-shape fiber has a better reinforcement effect.Wave-shape fiber can significantly improve the interfacial shear strength of soil,interfacial shear strength and residual shear strength decreases with the increase of water content,and increases with dry density increase.The addition of lime and cement can significantly improve the strength of wave-shape fiber reinforced soil,and the interfacial shear strength and residual shear strength of wave-shape fiber reinforced soil both increase with the increasing of lime and cement content and curing time.(2)Tensile strength tests of wave-shape fiber reinforced soil were undertook to analyse tensile characteristics and pull mechanism of wave-shape fiber reinforced soil,discussing the effect of fiber content,water content,dry density,lime content and curing time,cement content and curing time on tensile strength of wave-shape fiber reinforced soil.The results show that:wave-shape fiber can significantly improve the tensile strength of soil,and tensile strength increases with fiber content and dry density increased,and decreasing with the increase of water content;the addition of lime and cement can improve the strength of wave-shape fiber reinforced soil,and the tensile strength increases withincreasing lime and cement content and curing time.(3)Unconfined compressive strength test of wave-shape fiber reinforced soil is conducted,and the unconfined compressive strength of wave-shape fiber reinforced soil is analyzed,and the effect of fiber content,lime content and curing time on unconfined compressive strength of wave-shape fiber reinforced soil is also analyzed.Experiment result shows:wave-shape fiber can significantly improve unconfined compressive strength,and unconfined compressive strength increased gradually with decrease of fiber content;the addition of lime can also strengthen the strength of wave-shape fiber reinforced soil,and lime content and curing time are greater,unconfined compressive strength is stronger.Howerver,brittleness of soil would increase with the addition of lime,the greater lime content is,the easier soil happen a brittle failure.(4)The CBR test of wave-shape fiber reinforced soil are carried out to investigate the bearing capacity of wave-shape fiber reinforced soil,and to analyze the influence of fiber content,fiber length and lime content on the bearing capacity of wave-shape fiber reinforced soil.Test results show that:fiber can greatly improve the bearing capacity of soil,and with the increase of fiber content,the CBR values firstly increased and then decreased,and the optimal fiber content is 0.4%.With the increase of fiber length,CBR values decrease guadually.and the bearing capacity also decrease.Lime distributed to soil can obviously enhance the bearing capacity of fiber reinforced soil,and the more the lime content is,the greater CBR value are.and the bigger the bearing capacity is.(5)Fiber reinforced soil slope model test is carried out,and the slope is sensing based on BOTDA and FBG technology,and slope is loaded by the method of loading step by step in the part top of the slope,and the effect of fiber content on the stability of fiber reinforced soil slope is analyzed.The slope model is analyzed by finite element numerical simulation based on the experimental conditions,and displacement deformation in the horizontal direction in the each level load conditions is obtained.The results of numerical simulation show that in the condition of loading on the top of slope the horizontal deformation of the slope after the load is in a compressed state,and decreases gradually with the increasing of depth,and the horizontal deformation of the slope befor the load is in a loading state,and first increases and then decreases with the depth.The maximum horizontal displacement appears in the middle of the slope.The slope model test results show that the distributed optical fiber technology can obtain the information of the internal strain field of the reinforced soil slope during loading.With the increase of part load loading on the top of the slope,horizontal displacement increases gradually.Fiber can significantly improve the stability of slope,better prevent the displacement and deformation of slope.(6)Wave-shape fiber can significantly improve the soil mechanical properties,and fiber distributed in soil can enhance the interfacial shear strength,tensile strength,unconfined compression strength,the bearing capacity of the soil,and present the shear failure modeof soil,and increase the residual strength and make soil be of better toughness.Compared to straight fiber,the reinforcement effect of wave-shape fiber presented in this paper is better,and the mix technology is more simple and easier,and wave-shape fiber is of better engineering promotion value.