When is the construction project backfilled, and what kind of soil is generally used for earthwork b

For the backfill on both sides or around the underground facilities project (such as underground structures, ditches, pipeline trenches, etc.) and the upper part, the underground engineering should be inspected first, and the backfill can only be carried out after the acceptance procedures.

There are three methods of earthwork backfilling for construction projects:

1. Artificial filling method.

2. The mechanical filling method generally has bulldozer filling; scraper filling; There are three types of car filling.

3. Compaction methods generally include rolling method, tamping method and vibration compaction method, as well as compaction by using earth-moving tools. For large-area filling projects, rolling and using earth-moving tools are mostly used for compaction. For smaller areas of earthfilling, it is advisable to use tamping tools for compaction.

The foundation of the project is basically completed, and the rebound is completed (rebound: concrete strength rebound), and it can be backfilled.

Backfill. Back-filing refers to the return of the filled soil after the completion of the foundation and other works below the ground during the construction of the project.

Backfill refers to the construction process of taking soil and backfilling within 5m after the completion of concealed projects such as foundation and cushion.

Second, why backfill:

1. Fill the foundation of the building to protect it;

2. The fill soil can reach the design elevation, so that the ground can be done.

The foundation of the project is basically completed, and the rebound is completed (rebound: concrete strength rebound) can be backfilled.

If the completion is plus or minus zero, the backfill condition is met.

If the basement exterior wall is framed, the waterproof layer and protective layer must be completed.

In short, it is plus or minus zero after drying.

After the foundation is completed and the groove inspection is completed.

A foundation acceptance project with a basement has just been completed today.

1.The quality supervision station completes the basic acceptance;

2.Complete the construction of waterproofing and protective layer of the basement exterior wall;

And the 28-day strength of the concrete meets the design requirements.

The quality supervision station has passed the acceptance of the basic division.

1. Layered backfill, layered thickness is related to rolling equipment, generally 200-350mm; 2. Soil requirements;

3. The density requirement is generally greater than 91%.

About three days.

The foundation pit is a soil pit excavated at the foundation design position according to the base elevation and the size of the foundation plane. Before excavation, the excavation plan should be decided according to the geological and hydrological data, combined with the situation of the buildings near the site, and the waterproof and drainage work should be done. The excavation is not deep, and the method of putting the slope can be used to stabilize the soil slope, and the size of the slope is determined according to the relevant construction regulations.

If the excavation is deeper and there are buildings nearby, the foundation pit wall support method can be used, the shotcrete wall protection method, and the large foundation pit even adopts the methods such as underground diaphragm wall and column-type bored pile chain to protect the outer soil layer from collapsing; If there is no influence on the nearby building, the groundwater level can be lowered by the well point method, and the slope excavation is adopted; In cold areas, natural air-conditioning freezing method can be used for excavation, etc.

Calculation method: The foundation pit is a temporary project, and its function is to provide a space so that the masonry operation of the foundation can be carried out according to the location specified in the design. The amount of foundation pit excavation is calculated according to the volume of the foundation pit. Generally speaking, a deep foundation pit refers to a foundation pit with an excavation depth greater than or equal to 5m.

The calculation formula of foundation pit excavation is as follows:

1. No slope and no retaining plate: the foundation pit at this time is a cuboid or cylinder.

1) When it is a cuboid: the amount of excavation of foundation pit = (A+2C)(B+2C)H.

2) When it is a cylinder: the amount of excavation of foundation pit = *r*r*h.

2. Grading: The foundation pit at this time is a prism or a round platform.

1) When it is a prism: the engineering quantity of digging foundation pit = (A+2C+Kh)(B+2C+Kh)H+1 3 K*K*H*H*H.

2) When it is a round platform: the amount of excavation of foundation pit = 1 3 h (r*r+rr+r*r).

The concrete can be cured for 28 days or the concrete strength reaches 90.

For the basement waterproofing work or other construction content, it can be backfilled only after the work is completed. The foundation acceptance includes a concrete test, and the foundation pit can be backfilled in advance if the pit is small. The backfill should be evenly backfilled, and the backfill should not be completed first, so that the lateral pressure is larger.

After the age of the foundation concrete is reached, the quality inspection institute will test the pressure of the concrete pressure test block, and after the pressure test is qualified, the foundation acceptance will be organized, and the backfill can only be filled after the acceptance is qualified. If you don't follow the procedure, you will get yourself in a lot of trouble.

It's foundation concrete, right?

If so, then the backfill can usually be carried out only after the age is reached, the strength assessment is completed and qualified, and the foundation acceptance is completed.

For about three days, the pressure on the side of the backfill is not greatly affected, but why is it so anxious to backfill, and how convenient it is to throw everything that can be thrown in and backfill when it is finished.

If you want to catch up with the construction progress, you can backfill the soil after the template is removed!

1) Crushed stone soil, sand (the consent of the design unit should be obtained when using fine and silty sand) and blasted stone slag can be used as fillers below the surface. Its maximum particle size shall not exceed 2 3 or 3 4 of the thickness of each layer (when using vibrating rollers), and the moisture content shall comply with the regulations.

2) The moisture content of cohesive soil should be tested, and it must meet the requirements of the design and construction specifications before it can be used.

3) Saline soil is generally not usable. However, the filler shall not contain salt crystals, salt blocks or rhizomes of salt-containing plants, and can be used in accordance with the provisions of Table 1 8 of Appendix I of the Code for Construction and Acceptance of Earthwork and Blasting Engineering.