A New Design of Bridge-Subgrade Transition Sections Applied in Beijing-Shanghai High-Speed Railway

Table 1

Compaction quality test results for graded gravel transition section.

Testing time	Coefficient of subgrade reaction (MPa/m)	Dynamic modulus (MPa)	Static modulus (MPa)	Porosity; (%)
Filling standards	≥150	≥50	≥80	<28
Testing results for 4 h after finishing the filling of transition section	151	58	162	15~20
Testing results for 1 day after finishing the filling of transition section	431	170	446	—
Test results for 2 days after finishing the filling of transition section		174	449	—
(Testing results – filling standards)/filling standards (%)	188	241	459	—
(Testing results – filling standards)/filling standards (%)		248	461	—

Note: when testing of the transition section on the third day, the result cannot be tested because the strength of the graded gravel mixed with 5% cement is comparatively large, and when the hydraulic jack reaches its max top elevating force, the subsidence of loading board cannot reach 1.25 mm.