Predicting Bearing Ratios of Granular Soils Using Dynamic Cone Penetrometer and Modified PENCEL Pressuremeter Tests

摘要

California bearing ratio (CBR) values were estimated from in-situ dynamic cone penetrometer (DCP) tests. A shortened version of the PENCEL pressuremeter, called the modified pressuremeter test (MPPMT) was developed. MPPMT results were compared to DCP based CBR's. MPPMT data was recorded digitally, using instrumentation and data acquisition. Tests were conducted in base and subgrade soils at three sites in Brevard County, FL. The MPPMT probe is 15 cm (6-in.) long; its diameter is the same as the PENCEL probe, but it is not covered by protective metallic sheathing. It produces a stress-strain response in layers 15 cm (6-in.) or thicker in properly sized holes. MPPMT data were reduced to lift-off pressure, limit pressure, initial elastic modulus, and reload elastic modulus. Statistical correlations were established between these parameters and DCP-CBR values. The results indicated that lift-off pressure and limit pressure both correlated well with CBR. The results also showed a weak correlation between initial elastic moduli and CBR, and a poor correlation between reload elastic moduli and CBR. It was concluded that MPPMT test results are reliable in Central Florida base and subgrade soils.