KAJIAN KEKUATAN TANAH DALAM PERENCANAAN JALAN TOL SEMARANG - UNGARAN SEKSI II GEDAWANG - PENGGARON DI STA 3+500 Sampai STA 8+450

Abstract

The stiffness and strength of soil sub grade play an important role in determining the performance of roads. The purpose of this research is to know kind of lithology in located area and determine the stiffness or strength of soil sub grade by doing geotechnical survey such as geology mapping, geotechnical mapping, field investigation and laboratory investigation. The strength of the sub grade (soil below the pavement) is assessed using a test known as the California Bearing Ratio test. The minimum value of CBR for road is 6%. Standard penetration (SPT) is testing together with machine bor, minimum value of SPT for road sub grade is 15 (N SPT ≥ 15) will be interpreted as stiff soil. For cone penetrometer test, sub grade with conus resistance (qc) > 60 kg/cm2 will be interpreted as stiff soil. Result of the investigation are: CBR value for cut material = 7% - 21%, for fill material = 8,20% - 18%. From bor test in depth of 2m – 12m SPT ≥ 15. CPT test in depth 0,20m – 7,20m, qc > 60 kg/cm2.