Analysis of soil subgrade bearing capacity for clay using laboratory testing data

Abstract Road construction failures are often caused by unsupported subgrade classification. The purpose of this study was to determine the bearing capacity of subgrade on clay using test data in the laboratory. The contribution of this study can later be a recommendation in the use of subgrade types of clay and alternative uses. One of the properties of land strength associated with roads in the California Bearing Ratio (CBR). The method used is soil physical testing and CBR testing. The soil sample used was undisturbed soil in the subgrade in Minas District, Siak Regency, Riau Province. The result showed that the clay studied was non-organic Sandy Lean Clay CL) with low plasticity based on the USCS classification table. 2.681 specific gravity, water content 29,94%, liquid limit 33.64%, plastic limit 23,67% and plasticity index 9.97%. Soaked CBR test results obtained 4.21% and included in the medium classification. The use of this type of clay soil for subgrade with the bearing capacity of CBR classification needs to be pursued with alternative improvements and soil reinforcement that can increase the CBR value to a minimum of 6%.