Study On The Stress Transferring Law Of Regularly Arranged Lightweight Spherical Materials Subgrade

Light spherical material is well-known for its advantages like light weight, high strength and fast construction as a new kind of subgrade. In order to analyze the stability of the subgrade, it is important to study the stress transfer of this material. However, the discreteness of this material made it hard to use traditional soil mechanics to analyze the stability.So, the study of the stress transfer of this material is based on the theory of the contact force of regular accumulation and contact force test. The research contents and conclusions are as follows:First, light spherical material mold was improved based on the shortages of the old one. Also, a new way of sample shaping method that matches this mold was established.Second, the stress transfer theory of both regular and closely arranged towdimensional arrays and body-centered cubic packing under vertical concentrated load or vertical uniform load. This theory is based on static equilibrium theory and stochastic theory. Using the theory in this paper, the equations of different contact force can be established. Using these equations, the regularities of distribution can be analyzed.Third, load cells were used in order to check the stress of the bottom of each layer. As the result, the regularities of distribution of both regular and closely arranged tow-dimensional arrays and body-centered cubic packing can be obtained. After analyzing the difference between measurement and theoretical result, it is believed that the key reason of this phenomenon is the light difference of size and stability of load mode. The linear correlation of the peak value of test value and theoretical value of the contact force was established. Because of this correlation, the way to ensure correction factor was established.Last but not least, according to the destruction test, the damage form is the brittle cracking after the appearance of large plastic deformation. It is believed that Hertz contact theory is not suitable here. This paper suggests using the contact force when the material reaches its elastic limit as one of the standard to control the subgrade height. Based on this standard, the maximum filling depth of this kind of material was calculated and the depth meet the requirement of the filling depth of normal subgrade.