(1) Rolling roadbed with static smooth road roller
Static smooth road roller is only suitable for rolling dilute filling roadbed. This is because the static smooth roller between the contact area and soil is large, the unit pressure is very small, and from the surface down the compaction ability is gradually reduced, so that the density of the upper layer is greater than the density of the lower layer, and the compactness of the entire roadbed is poor.
When static smooth roller is used, thin filling and slow transmission should be used for many times, that is, filling ten layers of thin thickness (about 25~30cm), and the rolling speed is slow and fast, light and heavy grinding.
(2) rolling roadbed with tire road roller
Tyre roller is suitable for compaction of all kinds of soil, the most effective compaction relative to wet clay soil. Effective depth of compaction can reach more than 30cm.
The biggest characteristic of tire roller is that it can change the internal pressure of the tire according to the soil condition, and the maximum stress of the soil is controlled within the limit strength range of the soil: another characteristic is that the pneumatic tire is deformable, so that the depth of soil compaction is kept within a certain depth range; The third characteristic is the tire and soil contact area is large, the pressure distribution is uniform, the soil compression time is long, the compaction density is good.
(3) Compaction of roadbed with vibratory road rollers
① When rolling rockfill roadbed, vibratory road rollers of different tonnage should be selected according to the thickness of rockfill, and attention should be paid to the speed of the roller. In general, the compaction effect is proportional to the rolling pass, and inversely proportional to the driving speed: the experiment shows that when the driving speed is 3~6km/h, the compaction effect is the best.
② High frequency and low amplitude vibration road roller can be used when rolling sand and gravel and other non-clay roadbed. The rolling speed varies in the range of 3~6km/h, and the rolling times are about 2~3 times. If the layer is too thick, the rolling speed can be reduced.
③ When rolling non-plastic silt subgrade, the thickness of road surface can reach 0.7~1.0m, and heavy roller of 10~ 15T can be used.
④ When rolling silty soil subgrade containing a certain amount of clay, vibratory roller with low or medium static pressure can be used.
⑤when rolling clay roadbed, large tonnage vibratory roller should be used; When rolling high strength clay roadbed, it is necessary to use lift foot road roller vibratory roller; When rolling clay subgrade, high amplitude and low frequency compaction method should be adopted. The compression speed is 3~4km/h.
