Piling electric steel pole foundation? The following Zhongda Consulting brings the specific performance of power steel pole foundation piling. The relevant content is for reference.
1. There are many types of pile end pressure grouting devices. According to the information collected by the author, there are 18 types of pile end pressure grouting devices in China;
2. The level of grouting technology has been greatly improved and perfected, so that the bearing capacity of end pile pressure grouting piles has been greatly improved compared with the initial use;
3. Many construction units have formulated end pile pressure grouting process operating procedures and quality control standards adapted to local conditions;
4. The number of articles on pile tip pressure grouting piles has also increased significantly. According to the author's collection, there are more than 200 articles scattered in relevant magazines and conference proceedings;
5. Pile tip pressure grouting piles have become an important pile type in deep foundations of civil construction. Preliminary analysis shows that hundreds of multi-story, high-rise and super-high-rise building pile foundation projects in China have adopted this type of pile;
< p>6. While developing pile tip pressure grouting technology, pile side pressure grouting technology has also been developed in China. Pile tip and pile side joint grouting (collectively referred to as post-grouting piles) has achieved more significant technical and economic benefits.The immersed tube rammed bottom-enlarged pile has the advantages of high single pile bearing capacity, no mud discharge and fast construction speed. Although this type of pile can set the enlarged head in a better bearing layer, the supporting area of ??the enlarged head is still limited, and a larger range of foundation soil has not been fully mobilized to participate in the load-bearing. Composite carrier rammed and expanded piles are a new pile type (patented technology) developed to address the problems existing in immersed tube rammed bottom expanded piles.
Composite carrier tamped pile expansion uses a slender hammer to tamp the hole. After the casing is sunk to the design elevation, the slender hammer hits the bottom of the casing to a certain depth, and the filler is put into the hole in batches. The pile is formed by repeatedly tamping and squeezing dry hard concrete with a slender hammer to form a composite carrier at the pile end, then placing a steel cage and pouring concrete into the pile body.
Compound carrier rammed and expanded piles are composed of a composite carrier formed by ramming and expanding dry hard concrete and filler with a slender hammer and a reinforced concrete pile body. Therefore, it has the ability to compact the foundation and expand the pile end area. Dual action.
Although composite carrier rammed and expanded piles are also called piles, they are different from traditional piles in that they look like piles but are not piles. For traditional equal-diameter reinforced concrete precast piles and cast-in-place piles, in order to improve the pile end resistance, the pile end is usually placed in the foundation soil layer with higher bearing capacity, or the pile end is enlarged to become a pile end enlargement head. Piles, these practices all cause the pile end load to be directly transferred from the relatively rigid body at the pile end to the relatively flexible soil there, and they do not fully mobilize the pile end foundation soil to participate in the load-bearing. For composite carrier rammed and expanded piles, the function of the composite carrier below the pile end is to disperse and transfer the load transmitted to the pile end to the bearing soil layer below it. Since the four components of the composite carrier gradually decrease in stiffness and increase in volume from top to bottom, in this way, according to the stress diffusion principle at the pile end, the load at the pile end passes from the rammed dry hard concrete body with greater stiffness but smaller volume. The compacted filling material, compacted soil and influencing soil are buffered and transferred to the bearing soil layer with smaller stiffness but larger bearing area, that is, the composite carrier with a stiffness between the pile body and the bearing layer acts as a buffer. It also plays a role in expanding the effective bearing area of ??the bearing soil layer.
It can be seen that the reinforced soil layer becomes a hard layer and the bearing layer below forms a double-layer foundation, which is the main body that constitutes the bearing capacity of the composite carrier rammed and expanded pile.
After comprehensive research and analysis on the construction period, etc., and technical and economic analysis and comparison, the economical, reasonable, safe and applicable pile type and pile forming technology were finally selected.
Our country has a vast territory, complex and ever-changing engineering geological and hydrogeological conditions, unbalanced economic development between the eastern and central and western regions, and different engineering requirements. A large number of construction practices have shown that the various pile types commonly used in my country have the following characteristics as a whole: large diameter piles and ordinary diameter piles coexist; prefabricated piles and cast-in-place piles coexist; non-squeezing piles, partially squeezed piles and squeezed piles coexist; drilling, punching and digging holes coexist in non-squeezed soil cast-in-place piles; hammering, vibration and static pressure methods coexist in squeezed-soil piles; grouting technology in partially squeezed-soil cast-in-place piles Front grouting piles and rear grouting piles coexist in France and China; advanced and modern process equipment coexist with traditional and older process equipment, etc. It can be seen that various pile types have suitable soil quality, environment and needs in my country, and there are also conditions for development, improvement and innovation.
What needs attention is that no pile type is omnipotent and has its own scope of application. The key is to find an entry point and maximize strengths and avoid weaknesses; no matter how good a pile type is, as long as the quality is not paid attention to during construction or its scope of application is exceeded, problems will occur. Quality problems may even cause major accidents and economic losses.
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