The geosynthetic reinforcement layer techniques have been widely used nowadays in the foundations and embankments. During the course of the design of the geosynthetic reinforcement layer

the confirmation of the stress diffusion angle is very important

but no good methods to calculate the stress diffusion angle. This paper presents the method of calculating the stress diffusion angle of geosynthetic reinforcement layer based on additional stress back-analysis; and then using this method

researching the setup parameters of geosynthetic reinforcement layer ( the thickness of geosynthetic reinforcement layer

the composite modulus of compressibility of geosynthetic reinforcement layer) and geosynthetic factors (such as reinforcing space

reinforcing width

total numbers of geosynthetic reinforcement layer etc.)on the distribution rule of the stress diffusion angle; the results indicate that the range of the stress diffusion angle is 45-60 º; further more the setup parameters of geosynthetic reinforcement layer and geosynthetic factors existing optimum values

corresponding on these values

the stress diffusion angle reaches the max. Finally

using orthogonal tests and regression methods

many effect factors on the stress diffusion angle are analyzed

the results indicate reinforcing space has a most effect on the stress diffusion angle of the geosynthetic reinforcement layer

secondly the embedded depth of the first geosynthetic

however

reinforcing width has a slight effect on the stress diffusion angle.