1 Schematic diagram of gravel pile construction Fig.
A hole slightly larger than the diameter of the vibrator is formed outside the hole.
In addition, due to the significant increase of foundation width and relative density, the anti liquefaction performance has also been improved.
2 Schematic diagram of gravel pile construction Fig.
The so-called gravel pile method refers to a method used to strengthen the foundation when building embankment and other structures on soft foundation.
▼ click the business card to pay attention to ▼ gravel pile, which is a kind of bulk pile.
The reinforced foundation soil can meet the requirements of bearing capacity, deformation and liquefaction resistance.
This forced compaction increases the relative density of sand, reduces the porosity, increases the weight and internal friction angle of dry soil, and improves the physical and mechanical properties of soil, Greatly improve the bearing capacity of the foundation (generally 2 ~ 5 times).
At present, there are three main types of vibrator: zcq-13, zcq-30 and zcq-55, of which zcq-30 is a commonly used tool..
Gravel piles are sometimes used to improve the anti sliding capacity of soil slopes.
4 construction of dynamic compaction replacement gravel pile Fig.
The crushed stone is poured into the hole, and the crushed stone is squeezed into the surrounding holes under the lateral force of the vibrator to form a pile with certain compactness and large diameter.
The main machines and tools are vibro punch, crane or special flat car and water pump for construction.
3 construction of vibrating sinking gravel pile Fig.
Construction and quality control of gravel pile 1.
During the construction of gravel pile, the saturated loose sand particles are rearranged and compacted under strong high-frequency forced vibration, and after a large amount of coarse aggregate is filled in the vibration hole, it is squeezed into the surrounding soil by strong horizontal vibration force.
Reinforcement mechanism of sandy soil gravel pile mainly plays a role of compaction in sandy soil.
Although the bearing capacity of cohesive soil is not improved, the bearing capacity of the whole foundation is improved.
When gravel sand, coarse sand, medium sand, round gravel, breccia, pebble and gravel are used as filling materials, the pile is called gravel pile.
The gravel pile made by the pile making process of vibration and water flushing is called Vibroflotation Gravel Pile or wet gravel pile.
Because the material is gravel, it is called gravel pile.
Gravel pile method has been widely used in areas lacking well graded sand.
Fig.
According to the purpose of foundation reinforcement, it can be divided into gravel drainage well method and gravel pile method.
Gravel piles made by various water free punching processes (such as dry vibration, vibration extrusion, hammering, etc.) are collectively referred to as dry gravel piles.
The main purpose is to improve the bearing capacity of foundation soil, reduce deformation and increase liquefaction resistance.
Therefore, since the gravel pile foundation treatment method was introduced into China, it has been rapidly popularized in the foundation reinforcement of a large number of industrial, civil buildings and water conservancy and transportation projects, and achieved good results.
At the same time, start the water pump to make the high-pressure water spray the high-pressure water flow.
Reinforcement mechanism of cohesive soil for cohesive soil foundation (especially saturated soft soil), due to the large content of clay particles, strong binding force between particles and low permeability, the water in the soil is not easy to be discharged under the action of vibration force, so the role of gravel pile is not to compact the foundation, but to replace it.
So as to achieve the effect of strengthening soft foundation.
After reaching the required compactness, lift the vibrator, repeat this, fill and vibrate until it reaches the ground, so as to form a very dense pile with large diameter in the foundation.
The application of vibroflotation method in China began in 1977.
It uses a crane to lift the vibrator, starts the submersible motor and drives the eccentric block to make the vibrator produce high-frequency vibration.
Vibroflotation (wet) gravel pile and dry gravel pile.
6 gravel pile 2 Application of gravel pile in soft soil foundation the so-called soft soil foundation refers to the foundation composed of silt, mucky soil, alluvial fill, miscellaneous fill or other highly compressible soil layers.
At this time, the role of the pile, like the general anti slide pile, is to improve the shear strength of the soil, and force the sliding face away from the slope and transfer to the depth.
Therefore, the correct treatment of soft soil foundation is an important link in highway construction in China.
Because the Vibroflotation Gravel Pile pollutes the environment with mud and water, its application in cities and existing buildings is limited, and it can soften soil.
The gravel pile is a good drainage channel and can reduce the excess pore water pressure in the event of earthquake in this area in the future.
2 vibration water flushing method is a machine with the prototype of modern vibroflotation device designed and manufactured by Keller company in Germany in 1937, which is used to compact sand and gravel foundation successfully.
Vibro soft soil foundation is widely distributed in China, especially in the southeast coast.
2.
Construction of gravel pile (1) introduction of construction machines and tools.
5 gravel pile 1 Fig.
After hole cleaning, Gravel can be gradually filled from the ground to the hole, and each section of filler is vibrated and compacted under the action of vibration.
According to its pile making process, it can be divided into: point me: receive the project gift package.
Under the combined action of vibration and flushing, the vibrator will sink to the predetermined depth in the soil.
In the early 1960s, vibroflotation method began to be used to strengthen cohesive soil foundation.
The ratio of pile stress to cohesive soil stress between piles is called pile-soil stress ratio, which is generally 3 ~ 5.
Therefore, since the 1980s, various construction processes have been produced accordingly, such as hammering method, vibration extrusion method, dry vibration method, pipe sinking method, vibration air impact method, bagged gravel method, dynamic compaction gravel pile replacement method, etc.
The so-called vibroflotation method is the abbreviation of vibroflotation method.
Click me: get the project gift bag.
Fig.
1.
It forms a composite foundation with the original clay and works together.
Therefore, most of the load will be borne by gravel piles.
During construction, the cohesive soil is changed into mud water by the vibrator with the help of its self weight, horizontal vibration force and high-pressure water.
It takes gravel (Pebble) with unbonded strength as the main material, forms holes in the soft foundation by means of vibration, impact or water flushing, and then compresses the gravel (Pebble) into the soil hole to form a dense pile composed of large-diameter gravel, Composite foundation reinforcement pile composed of gravel (Pebble) pile and soil between piles.
Because the stiffness of gravel pile is much larger than that of cohesive soil around the pile, and the stress in the foundation is redistributed according to the material deformation modulus.
