In this way, the compactness of the subgrade can be ensured and the construction period can be achieved.
Ash mixing, crushing, mixing and preliminary rolling must be completed within the same day.
The moisture content is less than the optimal moisture content, It is not easy to be compacted to the specified compactness.
Especially in the case of no cover, the effective calcium and magnesium content will decrease greatly, and the expected effect cannot be achieved after mixing.
In this way, the specified compactness can be achieved and the construction procedure is simplified..
When the rotary tiller is used to turn and smash the inner layer of wet soil, the outer layer of soil will also be dried together and become dry soil again.
At the same time, rain proof cloth shall be used to cover them.
3.
If the moisture content of the wet soil after drying treatment is too large, it can be excavated from the borrow pit, stacked beside the pit for preliminary drying, and then transported to the construction section for paving; Or, after being excavated from the borrow pit, it shall be transported to one side of the operation section.
The accepted road sections should not be placed for a long time, and the upper soil should be filled in time to avoid exposure and rain, so as to avoid unnecessary rework.
Precautions for the treatment of over wet soil: the construction of over wet soil should focus on the continuity of the construction process, seize the time, carry out surprise attacks, pay attention to the weather forecast, and try to avoid rain.
4.
Therefore, before the backfill is placed on the subgrade, it should be turned and smashed outside the site until the moisture content is uniform and about 2% higher than the optimal moisture content, and then backfilled.
The loose paving thickness of filling treatment shall not be greater than 30cm.
The lime must be fully digested and strictly screened before use, so that the subgrade is treated with less lime that is not fully digested.
In some places with serious water accumulation, the wet soil can be excavated and replaced with evenly mixed lime soil, and then leveled and rolled until the compactness is qualified.
Measures to be taken for construction of over wet soil 1.
Therefore, when this kind of soil is used for subgrade construction, it needs to be mixed, dried, crushed, or even mixed with a certain proportion of lime to reduce its water content and improve the compaction characteristics.
Therefore, during subgrade filling, it is necessary to repeatedly turn over the sun.
Rainproof cloth shall be used as a temporary chute on the subgrade slope to prevent the slope from being destroyed by heavy rain.
Treatment method in rainy days: in case of rain during construction, it is generally advisable to rush the pressure and seal the lower soil with the upper soil.
For the formed road sections, in order to prevent the rain water from penetrating into the soil foundation, the rainproof cloth shall be used to cover the whole before the rain.
In this way, it can be mixed with little or no ash, At the same time, it can also reduce the granular pockmarks formed by the soil blocks.
For the road sections mixed with lime but not leveled and rolled in time, rush compaction shall be carried out in case of rain.
After leveling, the heavy roller shall be used for rolling until the specified compactness is reached.
The soil is muddy in rainy days, and the clay surface is dry in sunny days, but the water content of the soil layer is about 30%.
As the road sections are uneven and partially infiltrated into the rain sections, the rain proof cloth shall be opened immediately after the rain stops, and local turning shall be carried out.
In this way, lime can be added or not, which can not only achieve the specified compactness but also simplify the construction procedure.
Sometimes, the number of times of turning over the sun is as high as 5-6, which brings considerable difficulties to the construction and also affects the construction progress.
Control of water content: since the natural moisture content of the over wet soil is high and will increase after rain, the optimal moisture content must be strictly controlled during construction.
2.
During construction in high-temperature season, the over wet soil is easy to dry after exposure, but the moisture content inside is still large.
Selection and treatment of soil field: due to the high underground water level of the soil field in the road section, the water content of the soil is particularly large.
After rolling and forming, the lime that is not fully digested will continue to be digested in the process of rain, which will cause local swelling and swelling, forming a mushroom shape, and affecting the strength and flatness of the subgrade.
The moisture content is less than the optimal moisture content and it is not easy to press to the specified compactness.
6.
When the rotary tiller is used to turn and smash the inner layer of wet soil, the outer layer of soil will also turn into dry soil.
At the same time, the drainage function shall be strengthened.
The moisture content of the lime soil shall be measured to make it reach ± 2% of the optimum moisture content.
Therefore, before the backfill is placed on the subgrade, it should be turned over and crushed outside the site until the water content is uniform and about 2% higher than the optimal water content.
Characteristics of over wet soil in highway construction, some borrow areas along the line are silty medium weak expansive clay, with high plasticity index, liquid limit index, natural moisture content, low permeability, high moisture absorption, and easy to lose stability.
12 for the sections treated with lime, lime shall be fully digested and screened before use, but the lime stacking time shall not be too long.
In order to ensure normal transportation after rain, the access roads to and from the soil yard shall also be carefully repaired.
Since the natural moisture content of the over wet soil is more than 30%, and the moisture content will increase after rain, the optimal moisture content shall be strictly controlled during construction.
Each layer shall be sunned and crushed.
5.
After the rain passes, the rainproof cloth shall be opened, necessary re compaction shall be carried out, and the compactness shall be re tested.
After being preliminarily dried, it shall be pushed onto the operation section by the bulldozer, crushed by the above-mentioned machinery for 1-2 times, and after being leveled, all or 2 / 3 of the specified dosage of admixture shall be evenly distributed on the surface.
The moisture content must be controlled within 11% ~ 15%, or it is easy to turn over during rolling.
The next process can be carried out only after it is qualified.
During construction in high temperature season, the over wet soil will be dried quickly, while the moisture content of the inner soil is still large.
Laying treatment: after 24 ~ 28h of the initially compacted soil layer, the remaining 1 / 3 lime shall be evenly spread on the soil layer, and then mixed.
Control of moisture content of over wet soil.
The lime with the original quality meeting the requirements can be stacked for several months without cover, and its quality can be reduced to substandard lime.
Only when the water content of the filling is uniform and the particles meet the specification requirements can it be leveled and rolled to the specified compaction degree.
In order to reduce the water content of the soil, the method of ditch drainage around the borrow pit is first adopted, and then the bulldozer is used to push the soil into a large pile for drying, so that the earth can be directly transported to the subgrade for filling.
