Small roller is a very widely used type of roller, different from large roller, small roller for rolling road edge position and corner position has unique advantages, whether in large roads or rural roads can see the shadow of small roller, then small roller rolling effect how?
Subgrade construction quality and stability of concentrated embodiment is in the compact degree of small roller. The quality of compactness not only directly affects the quality of pavement, but also has a great influence on the use of the whole highway in the later period. The embodiment of the compaction effect is mainly related to the soil quality, water content, amplitude, vibration frequency and the number of rolling passes. The specific reasons for affecting the rolling quality are as follows:
1. Soil quality
The compacting properties of different types of soil are different. As far as filling compaction is concerned, the suitable soils are gravel soils, sandy soils and sandy soils, which are easy to be compacted, have sufficient stability and have little settlement. Difficult to compacting is clay, which is unstable in the wet state, has a higher water content than other soils and a lower dry density, but compacted clay still has good water permeability.
2. Water content
Water content has a great influence on the compaction effect. Water content should be controlled both in trench backfilling and subgrade compaction. Strictly control the water content within the range of water content ±2%. In this state, the gravity between soil particles is small, and the water film is thicker, which plays the role of lubrication. External compaction is easier to make the soil particles move relative, and the compaction fruit is good.
When the water content in the soil is too large, free water appears in the pores, and it is impossible for the compaction function to discharge the gas. The part of the compaction function is offset by the free water, which reduces the pressure, and the compaction fruit decreases instead. When the water content is small, the gravitation between soil particles is larger. Although the dry bulk density is larger, its strength may be higher than that when the water content is small. But at this time because of low density, porosity, after saturation, its strength will drop sharply.
3. Frequency and amplitude
Vibration frequency and amplitude are important performance parameters of compaction operation of vibratory roller. Vibration frequency refers to the number of vibrations of the vibration wheel within a unit time, and its unit is HZ. Amplitude refers to the height of the vibration wheel from the ground during vibration, and its unit is mm. The amplitude parameter is an indicator called amplitude, that is, assuming the vibration on the elastic surface, the vibration wheel is completely free to hang from the ground height. The actual vibration pressure is real, and the actual amplitude is generally slightly larger than the nominal amplitude. High vibration frequency, the surface flatness of the compacted layer is good; The amplitude is large and the exciting force acting on the compacted layer is large. According to the operation content, vibration frequency and amplitude coordinate each other, in order to obtain a better compaction effect.
4, the thickness of the rolling layer and the number of rolling passes
The speed of compaction also has an effect on the compacted fruit. The compactness requirement is higher, when the soil layer is thicker, the driving speed is slower. Rolling should start with a slow speed, with the gradual compaction of the soil layer, the speed gradually increased. At the beginning, the soil is relatively loose and the strength is low. It is advisable to press lightly first. With the increase of the soil density, the pressure of the small roller is gradually increased. Therefore, when pushing and spreading soil material, mechanical vehicles should be evenly distributed in the entire width of the embankment, so that the fill can be evenly preloaded. Formal rolling, if the vibration roller, should be static pressure, and then from weak vibration to strong vibration.
Contact: Ms. Anna
Add: Incalcu Industrial Park, 327 National Road, High-tech Zone, Jining City, China., Jining, Shandong, China