In most cases, it should be the reason of low water content in lime soil.
Other reasons:
First, shrinkage cracks caused by excessive ash mixing;
Second, the lime is not digested completely, and it rolls in the water to produce expansion cracks.
Third, the smoothness of the subbase is not enough, and uneven rolling may cause cracks.
Precautions: After the lime-soil compaction is completed, a large amount of water must be sprayed for maintenance. When the temperature is too high in summer, be sure to cover it with felt to avoid exposure to the hot sun for a long time.
When lime stabilized soil is rolled and formed, it often appears local flooding, looseness, and large-scale peeling, and the local water content is too high, which is easy to cause flooding; Uneven mixing or partial segregation of coarse and fine particles easily leads to looseness; The surface is too dry, and the thin layer of grader is easy to find, resulting in large area peeling; Improper rolling method of road roller is easy to cause packing and squeezing.
Extended data:
The function of railway subgrade is to lay the track structure directly on the subgrade surface. So the subgrade is the foundation of the track. The subgrade load not only bears the weight of the track structure, that is, the static load, but also bears the dynamic load transmitted through the track when the train is running. The line structure composed of subgrade and track is a kind of loosely connected structure, and its ability to resist dynamic load is weak.
During the rolling process, the surface of lime soil should always be wet, but the wheels should not be stuck. It is forbidden to repair thin layers, especially the lime soil below 50 mm. This kind of thin-layer repair phenomenon is common in lime-soil acceptance, which is mainly caused by the lax control of elevation by the construction unit.
Therefore, when paving, it is necessary to "rather high than low, rather than make up", and when the grader is finally leveled, "the cutter should not be too deep", and the surveyor should always follow up and monitor it. When rolling, the roller should follow the principles of "light before heavy", "edge before middle" and "slow before fast".
Baidu encyclopedia-lime stabilized soil
Baidu encyclopedia-subgrade