| 释义 |
ˈsubgrade
1. Road and Railway Engineering. [sub- 3 a.] The layer, either natural or constructed, lying immediately beneath the foundations of a road or railway line. Cf. substratum 4 b.
1893G. A. Perkins et al. in Rep. Mass. State Highway Comm. v. 78 The subgrade, or the ground on which the large stones rest, should be thoroughly compacted by rolling. 1906Engin. Rec. 14 Apr. 478/3 The reduced quantity of broken stone required, when it is laid on a firm sub-grade. 1930Engineering 1 Aug. 139/3 Maintenance of a mile of gravel road, including the sub-grade. 1962Ibid. 30 Mar. 439 The stresses transmitted to the subgrade by a high quality structural are so small. 1979Railway Gaz. Internat. Jan. 52/2 Protection of the sub⁓grade against frost.
2. [sub- 9 (a).] A subsidiary grade; one within a grade.
1919Sociol. Rev. XI. 90 We might perhaps recognise..an intermediate group, concerned chiefly with relations between sub-grades. 1931J. S. Huxley What dare I Think? vi. 218 In this stage of thought there are, of course, many sub-grades. |