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、孔内深层强夯法适用规划广泛，可用于各类地基处置：在地基处置工程中孔，能适用于各种凌乱地层的地基加固处置，具有广泛的适用性。如用于大厚度的黄土、杂填土、液化土地基，各类软弱土、湿陷性黄土以及具有酸、碱、盐腐蚀的地基，具有硬夹层的不均匀地基、石料及废料回填废物地基以及地下人防工事等各种凌乱修建场所的处置。

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.

通过钻孔、强力冲孔等方法成孔，只要能构成桩孔的地基，不管孔内有无地下水均可选用本法加固处置。总之，选用孔内深层强夯技能，既可地基土的湿陷性、液化性，也兼有承载桩的特征以及刚度均匀的复合地基的特征。不只承载力高，而且紧缩变形小。

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、用料标准低，量体裁衣：凡是无机固体材料如土、砂、石、碎砖瓦、混凝土块、工业废料及其混合物等均可运用。而且用料不需严厉加工，凡能填入孔内的无机固体材料均可运用。用料不需长途运送。

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、具有高动能、高压强和强挤密效应；

3. It has high kinetic energy, high pressure and strong compaction effect;

4、地基承载力前进明显；

4. The bearing capacity of foundation is advancing obviously;

5、地基加固处置深度大：一般处置深度为20m——30m，深时可达50m以上。而且上下均匀。持力层规划内的地基土层都可以加固，深层的软弱下卧层也可加固，可明显地改善土性。

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、成桩直径大，挤密加固范围大，桩呈串珠状：在高动能冲击挤压下，桩径一般可达500mm——2500mm左右，在松软土层中，具有更大的侧向挤密效应。在分层土中，桩体呈串珠状，桩间土呈“咬合”和“抱紧”的强挤密现象。采用粗粒料作加固材料时，桩体也是地基排水通道，有利于饱和土地基的排水固结。同时可将加固区范围内的土中水排挤到加固区以外的土体中去。改善地基土性，加固影响范围大。

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、复合地基压缩模量高，沉降变形小，承载性状好；

7. The composite foundation has high compression modulus, small settlement deformation and good bearing capacity;

8、社会经济效益好：具有高动能、高压强，在孔内深层强夯的特征，故振动小，噪音低，碴土污染，可广泛地应用于城市建设中地基的处理工程。能净化人类生存环境，将垃圾、碴土“变废为宝”，大量消耗废料。

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.