| With the revision of the Specification for Highway Bridges in 2002 (in Japanese)、 correction coefficients for scale effects were introduced for use in the calculation formula of the ultimate bearing capacity of spread foundation. Meanwhile、 soil moduli are often found using estimated formulas or other methods for practical reasons and are likely to be underestimated. As a result、 the bearing capacity may also be underestimated、 thereby leading to the design of uneconomical structures. Therefore、 a proper understanding of appropriate design constants based on scale effects is of great importance.[*]In this study、 therefore、 plate loading tests of the ground with different-sized loading plates were conducted using rock fills and gravel soils to examine the scale effect properties of the ultimate bearing capacity with changes in the form of spread foundation.[*]The results of the tests were examined and compared with the ultimate bearing capacity formula. As a result、 the following were revealed:[*]1)The same relationship of approximate expressions as in the Specification for Highway Bridges was recognized for the correction coefficient Sγ of the bearing capacity coefficient Nγ.[*]2)Because the parameter of the correction coefficient is not necessarily the same as the general value in the Specification for Highway Bridges、 it is necessary to study and calculate correction coefficients and soil moduli appropriate for on-site conditions.[*]The plate loading test with different-sized loading plates is effective as a method for studying design constants in the design of spread foundation taking scale effects into consideration. |
