In the dynamic compaction construction, the deep dynamic compaction method in the hole is a kind of deep foundation treatment method. In this method, the hole is first formed to a predetermined depth, and then the bottom-up dynamic compaction with layered filling or dynamic compaction with filling is carried out to form a dense pile with high bearing capacity and a strongly compacted soil between piles (DDC method for short).
1. The deep hole dynamic compaction method is widely used in planning, and can be used for all kinds of foundation treatment. In foundation treatment engineering, the deep hole dynamic compaction method can be used for all kinds of foundation reinforcement in disordered strata, and has a wide range of applicability. For example, it is used for the disposal of large thickness loess, miscellaneous fill, liquefied soil foundation, all kinds of soft soil, collapsible loess and foundation with acid, alkali and salt corrosion, uneven foundation with hard interlayer, stone and waste backfill waste foundation and underground civil air defense works.
This method can be used to reinforce the foundation of pile hole, no matter whether there is underground water or not. In a word, the deep dynamic compaction technique can not only eliminate the collapsibility and liquefaction of foundation soil, but also have the characteristics of bearing pile and composite foundation with uniform stiffness. Not only the bearing capacity is high, but also the shrinkage deformation is small.
2. Low material standard, tailored: all inorganic solid materials such as soil, sand, stone, brick and tile, concrete block, industrial waste and its mixture can be used. And the material does not need to be strictly processed, and any inorganic solid material that can be filled in the hole can be used. There is no need for long distance transportation.
3. It has high kinetic energy, high pressure and strong compaction effect;
4. The bearing capacity of foundation is advancing obviously;
5. The treatment depth of foundation reinforcement is large: the general treatment depth is 20m-30m, and the depth can reach more than 50m. And even up and down. The foundation soil layer in the bearing stratum planning can be reinforced, and the deep soft underlying layer can also be reinforced, which can obviously improve the soil properties.
6. The diameter of the pile is large, the range of compaction and reinforcement is large, and the pile is Beaded: under the high kinetic energy impact, the diameter of the pile can generally reach about 500mm-2500mm, which has greater lateral compaction effect in soft soil. In layered soil, the pile is beaded, and the soil between piles is "occlusive" and "tight". When the coarse-grained material is used as the reinforcement material, the pile is also the drainage channel of the foundation, which is conducive to the drainage consolidation of the saturated soil foundation. At the same time, the water in the soil within the reinforcement area can be squeezed into the soil outside the reinforcement area. It can improve the soil property of the foundation, and the influence range of reinforcement is large.
7. The composite foundation has high compression modulus, small settlement deformation and good bearing capacity;
8. Good social and economic benefits: it has the characteristics of high kinetic energy, high pressure and deep dynamic compaction in the hole, so it has small vibration, low noise, and eliminates the pollution of slag soil. It can be widely used in the foundation treatment engineering in urban construction. It can purify the living environment of human beings, turn waste into treasure and consume a lot of waste.