| Recently the environmental problems such as soil erosion, slope instability, desertification, dust storms and dust have seriously affected on people’s lives. A new type of soil stabilization materials named polymer soil stabilizer has become the key study due to its properties of changing the physical structure of soil; improving mechanical strength, water-stability, erosion resistance; unaffecting vegetation growth; optimizing the ecological environment. In this thesis, based on the principle of soil improvement, two types of soil stabilizers have been developed to modify the different soil properties of clay and sand. These soil stabilizers have the properties of superior performance, simple construction, high competitive and environmental protection. In the laboratory tests, the properties of strength, stability and erosion resistance were studied, the modification mechanism and application was analyzed and the corresponding findings are presented as follows:1. According to the principle of macromolecule polymerization and clay improvement, a new type of polyvinyl acetate soil stabilizer has been developed. Based on lots of experimental study, time of reaction, dosage of agents, temperature of reaction was understood, finally a series of polyvinyl acetate soil stabilizer products were obtained. They are the polymer soil stabilizers with superior performance, low cost, simple construction, high competitive, environmental protection, and can be applied to ecological protection, soil erosion control and other fields.2. The properties of unconfined compressive strength and shear strength parameters of the soil specimens treated by polyvinyl acetate soil stabilizers were studied. The best curing time and the optimal dosage of soil stabilizer were obtained. 3. Effect of soil stabilizer content and soil particle size on the linear swelling ratio and linear shrinkage ratio of soil specimens treated by polyvinyl acetate soil stabilizers were studied. The results show that polyvinyl acetate soil stabilizer can effectively suppress the swelling and shrinkage of expansive soils. The linear swelling ratio of specimen with the average particle diameter of0.75mm had a minimum value. The linear shrinkage ratio reduced with the increasing of soil particles size. Both linear swelling ratio and linear shrinkage ratio reduced with the increasing of soil stabilizers content.4. Effect of soil stabilizer content on water-stability and erosion resistance was studied. The results show that polyvinyl acetate soil stabilizer can improve the water-stability and erosion resistance of treated specimens.5. A new type of polyurethane soil stabilizer (or sand fixing agent) has been developed. Based on lots of experimental study, a series of polyurethane soil stabilizer products were obtained. The strength and erosion resistance of sand were improved by these products, due to the increasing of binding power during soil particles. They are the polymer soil stabilizers with superior performance, simple construction, high competitive, environmental protection, and can be applied to soil erosion control, desertification and dust prevention, sand fixation and other fields.6. The properties of unconfined compressive strength and shear strength parameters of the soil specimens treated by three types of polyurethane soil stabilizers were studied. The results show that the unconfined compressive strength and cohesion increases with the increasing of soil stabilizer, but the internal friction angle is rarely affected.7. Effect of soil stabilizer content on water erosion resistance and wind erosion resistance was studied. The results show that three types of polyurethane soil stabilizer can improve the erosion resistance of treated specimens.8. Base on the characteristics of clay and sand, the modification mechanism of two types of polymer soil stabilizers, named polyvinyl acetate and polyurethane soil stabilizer, was studied. Furthermore, the prospects of polyvinyl acetate and polyurethane soil stabilizer were analyzed. |
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