METHOD FOR SIMPLIFIED BEARINGGRATIO TEST OF SUBGRADE SOIL AND PENETRATION TEST MACHINE FOR SOIL

摘要

PURPOSE:To calculate apparent CBR values and simply test subgrade soil bearing- ratios by a comparison of results obtained from a penetration test by a tester equipped with sampling and measuring devices between base plates assembled at the job site, to those obtained from tests of sample soils carried out in advance at a test room. CONSTITUTION:A soil at the job site is sampled into a mold with holes 40 on a tester 1, made compact in three layers by rammer and immersed in water together with a mold for a specified time. A needle 24 of the tester 1 is penetrated into the specimen to measure a penetration resistance and read the maximum meedle resistance. On the other hand, an apparent CBR value equivalent to a deviation value of an index read at the test in the job site is calculated from a correlation figure drawn with a comparison between the needle resistances and the values obtained from a penetration test which is made on the same soil beforehand in a test room in accordance with the JIS subgrade soil bearing-ratio test method. By this method, apparent CBR values can be measured easily from needle resistances and accordingly a soil judgement is simplified.