Abstract:In the process of urban road construction, various geological conditions are usually encountered. The soft soil subgrade is one of the common geological problems. The roadbed of urban road is the foundation of pavement and should meet the requirements of strength, deformation and stability. Due to the soft soil with the characteristics of large natural water content, high compressibility, low bearing capacity and low shear strength, when soft soil is used as roadbed foundation, various subgrade reinforcement measures should be taken to treat the soft soil subgrade in order to make the urban roads able to satisfy the design requirements. Taking the South Tuanyuan Road Project in Yiyang City Economic Development Zone of Hunan Province as an example, the steps of establishing the finite difference method model of soft soil roadbed reinforced by preloading with plastic drainage board are introduced in detail through FLAC3D numerical calculation. The response of soft soil subgrade under the preloading and plastic drainage board is obtained through the numerical simulation, and the dissipation law of excess pore water pressure is obtained after preloading load is applied. The distribution characteristics of pore water pressure and consolidation settlement of soft soil roadbed under the preloading and plastic drainage board are revealed. Finally, the changes of pore water pressure, total settlement of each layer and stratified settlement of each layer in soft soil roadbed with the depth direction are obtained. The research conclusion plays a good guiding role in the treatment of soft soil subgrade.
