Study On The Strength Characteristics And Microscopical Experiment Of Soil Reinforced By Wheat Straw

Reinforced soil technology is an effective soil improvement technology,which can improve the strength of the soil,reduce the development of cracks in the soil and increase the permeability of the soil.Wheat straw as a natural reinforcement material not only has the interweaving effect of flexible materials,but also improves the frictional and quasi cohesive forces of the soil.At present,the research on wheat straw reinforced soil is mainly confined to the study of its mechanical properties,and the research on its reinforcement mechanism is still very few.In this paper,the shear strength index of wheat straw reinforced clay under different reinforcement length and reinforcement ratio was measured by three axis shear test.The microstructure and microstructure parameters of wheat straw reinforced clay were analyzed by means of microcosmic image of SEM in scanning electron microscope test.The number of sample CT in CT scanning section was calculated by CT scanning test.And the meso-structure such as cross section parameters and bulk ratio are calculated.By comparing and analyzing the characteristics and variation rules of micro parameters,the mechanical properties and reinforcement mechanism of wheat straw reinforced clay are studied.Through the analysis,the following conclusions are drawn:(1)Through the three axis shear test,it is concluded that the optimum reinforcement ratio of wheat straw reinforced clay is 0.18~0.22%,and the optimal reinforcement length is 9~11mm.(2)According to the SEM test,the qualitative analysis of two factors to improve the shear strength index improvement of wheat straw reinforced clay: the negative friction between wheat straw and soil,and the interweaving of wheat straw in soil to improve the tensile strength of wheat straw.(3)The SEM image of scanning electron microscope test was analyzed to deter mine that the equivalent diameter of wheat straw was smaller when the length of whe at straw was 10 mm.Under the external load,the interface between the reinforced soil and the soil will increase the frictional force between the interface of the reinforced earth and the soil,which will increase the strength of the soil and achieve the reinforcement effect.(4)According to the CT scanning test,CT images showed that the number of microcracks plain soil was significantly higher than reinforced soil,the fineparameters of the reinforced soil and the plain soil are analyzed.The density of the soil body is reduced by the incorporation of wheat straw rod,and the CT number in each strain state is increased.After the strain is greater than 10%,the change of surface density is smaller and the volume density varies greatly.