Study On The Mechanical Properties Of Geosynthetics Reinforced Rice Husk Ash Mixed Soil

As the main rice producing country in the world,rice is one of the main food crops in China.The annual output is nearly 200 million tons,and the rice husk accounts for about 20% of the rice weight.Although the rice husk resources are very rich,the utilization rate of rice husk is low in China,causing great waste of resources when it is used as fuel in rural areas,and it causes great pollution to the environment.Therefore,it is especially important to find a reasonable treatment for rice husk ash.Some Southeast Asian countries,which are also major rice producing countries,use rice husk ash as a roadbed filler to enhance the soil carrying capacity,solve the agricultural waste of rice husk and reduce environmental pollution.Therefore,the application of rice husk ash to building roadbed materials has research value and broad application prospects.In this paper,the rice husk ash mixed soil and the reinforced mixed soil were studied by triaxial test.Different ratios of rice husk ash and clay were mixed as the roadbed filler.The different proportions of rice ash mixed soil were tested by triaxial compression test.The mechanical properties and shear strength parameters of the mixed soil were analyzed.The test results show that adding different proportions of rice husk ash has a great influence on the shear strength of mixed soil.At low confining pressure,the early strength of rice husk mixed soil is better;Under the high confining pressure,it is “slowly hardened”.After adding rice husk ash,the soil elastic modulus and secant modulus increase significantly,and can increase to more than 1.5 times in a better ratio;Adding rice husk ash can effectively improve soil strength;When the ratio of rice husk ash is 15%,the tangential modulus reaches the maximum.That is,the 15% rice husk ash ratio can maximize the soil strength.In order to more accurately describe the stress-strain properties of rice husk ash mixed clay,a hyperbolic model,an exponential model,and a new nonlinear model proposed by Zhang Junhao et al.were used to simulate the rice husk mixed soil.The results show that the comparison of the three models shows that the hyperbolic model and the exponential model not only underestimate the initial tangent modulus of the rice husk ash mixed soil under high confining pressure,but also underestimate the overall strength of the mixed soil.Compared with the conventional hyperbolic model and exponential model,the tangent modulus model can more accurately reflect the actual stress-strain performance and strength characteristics of rice husk ash mixed soil.The parameters of the deviatoric and reinforced strength ratio of unreinforced and reinforced rice husk mixed soil under different axial strains,the actual force conditions under different test conditions can be derived to determine the design allowable value.Different strain levels of rice husk ash mixed soil have great influence on the performance of reinforced soil.