Laboratory Investigation On Rice Straw Reinforced Ecological Slope Protection

With China’s rapid economic construction development and large-scale basic construction,the express highways are gradually stretching to middle and west regions,however the problems of granite residual soil slope are increasingly emerging.The protection and greening of slope in the road construction and use of the process is the most important.For the problems that granite residual soil of high-risk expansion of water,very poor water stability is easy to form slope rain erosion before plant grows to a certain scale to against late growth stage of plants.So the study of ecological protection technology of granite residual soil slope is of great significance to improve the ecological environment along the expressway and ensure the safety,economy and comfort in the construction and use of expressway.Based on the science project“The Research on The Rainwater Disaster Mechanism and Ecological Treatment of Granite Residual Soil Slope under Complex Conditions",domestic and international research data and the field research,this article mainly aims at the rice straw reinforced indoor experimental research on ecological slope protection,the main idea is just as follows:The moisture content of the reinforced soil samples was changed by adding water method and drying method to simulate the mechanical properties in the construction and use process,and the direct shear test was used to study on the shear strength of reinforced soil under different reinforcement rate and moisture content.The results indicate that in different reinforcement ratio the shear strength,cohesion and internal friction angle of the reinforced soil samples obtained by adding water method increased first and then decreased with the increase of water content,but the samples obtained by drying method gradually decreased with the increase of water content.The effect of rice straw incorporation on the cracking behavior of soil was studied by the cracking test of rice straw reinforced soil at room temperature and simulated sunshine condition,and the better ratio of rice straw incorporation was obtained.The experiment results showed that rice straw stalk can effectively reduce the cracks in soil,whose limit reinforcement rate was 0.3%.According to the disintegration test of rice straw reinforced soil,it was concluded that the amount of disintegration and the average disintegration rate of the samples were related to the initial water content and the rice straw blending ratio.The amount of disintegration and the average disintegration rate of the sample increased with the decrease of the initial moisture content,but with the increase of the rice straw blending ratio,it showed a tendency to decrease first and then increase.The rainfall erosion test of the protective layer under different thickness and different rice straw blending ratio was carried out by the indoor rainfall device and the slope simulation device.The erosion condition of slope and the amount of scouring per time was used as the evaluation standard,the conclusion was obtained that reinforced soil has a good protecting effect when the rice straw incorporation ratio was 0.3%and the protective layer thickness was 5cm.