AN IMPROVED MURAYAMA RHEOLOGY MODEL TO DESCRIBE THE CREEP BEHAVIOR OF THE MIXTURE COMPOSED BY CALCAREOUS SAND AND POLYURETHANE POLYMER GROUTING

While grouting with polyurethane polymer significantly enhances the bearing capacity of coral calcareous sand foundations, accurately describing the total settlement and creep rate remains challenging. This study introduces an improved Murayama rheology model(IMRM)that pieceswisely describes the creep rate. The IMRM incorporates an inverse proportional function related to stress and time to replace the viscous coefficient in the traditional Murayama rheology model. The validity of the IMRM was assessed through uniaxial oedometer tests under pressures of 100, 200, and 400 kPa. The results indicate that the estimated values from the IMRM align well with the actually measured data throughout the entire experimental period. In contrast, the traditional Murayama rheology model proves effective only before the critical time. Higher stress applied to the soil samples results in larger settlements and an earlier occurrence of the critical time.