Construction technology of artificial backfill

1 scope

This technology is applicable to general industrial and civil building Foundation pit, trench, indoor flooring, trench, an outdoor fat Groove and apron artificial backfill.

2 construction preparation

2.1 materials and equipment:

2.1.1: appropriate priority using excavated soil in the trench, but must not contain organic impurities. Before using screening, its diameter is not more than 50mm, water should meet the requirements.

2.1.2 major equipment: frog-type ramming or diesel, trolleys, sieve (diameter 40~60mm), wooden rakes, shovels (sharp and flat), 2m feet, hose, small lines and Pocket rule.

2.2 operating conditions:

2.2.1 construction should be based on project characteristics, embankment soil types, density requirements, conditions and so on reasonable determination of fill soil moisture control, virtual shop times such as thickness and compaction parameters important backfill project, the parameters of which should be determined through compaction test.

2.2.2 before backfill Foundation, box-type Foundation wall or underground waterproof layer, protective layer, inspection and acceptance, and to run hidden procedures. The Foundation concrete strength should meet the requirements set, backfill can be carried out.

2.2.3 Fang Xin and backfill of the trench should be completing in-door plumbing and gas pipeline installation and reinforced the trench wall, then. And Groove, such as water and organic matter on the floor clean.

2.2.4 prior to construction, we should do a level mark to control the height or thickness of backfill. As in the pit (Groove) or trench slope, every 3M horizontally on the nail plate; indoor and elastic on the side wall on the apron level or elevation control stakes on the nails on the floor.

3 operational processes

3.1 process:

The Foundation pit (Groove) cleaning up → check → soil layer on the bottom floor shop dynamic compaction-compacting soil, rake → →

Acceptance of testing density → trim level

3.2 filling before excavation (Groove) or clean up the garbage and other debris on the floor; fertilizer tank prior to backfilling must be clear to the bottom surface of the base level will fall loose rubbish, sand, stones and other debris cleared.

3.3 test of backfill soil quality is free of debris, particle size for compliance, and backfill soil water content in the context of control if moisture content is too high, can be turned loose, dry or even mixed with dry measures such as; if the backfill of the moisture content is low, use the water wetting and other measures in advance.

3.4 the backfill layer casting. Each layer of thickness of bedding should be based on soil, density requirements and equipment performance. Frog-type ramming machine on each floor thickness of bedding for 200~250mrn artificial ramming is not more than 200mm. After each casting, with the rake.

3.5 backfill tamping each layer at least three times. Ramming a half RAM RAM pressure, poor consolidation phase, is connected to the line, vertical and horizontal cross. And non-irrigated soil sinking of the so-called "water RAM" legislation.

3.6 the depth two pit (Groove) are connected, fill deep dynamic compaction Foundation to form a shallow pit at the same elevation, then fill with the shallow Foundation consolidation. Subparagraph if it is necessary to fill in when tamping, junction shall be filled in a ladder, ladder aspect ratio is generally 1:2. Is less than the distance from the upper and lower joints 1.0M.

3.7 the Foundation pit (Groove) backfill around the opposite sides or both. Base elevation on both sides of the wall must not vary too much, so as not to crowd the walls awry; long trench wall, internal and support measures should be adopted, and then lateral backfill.

3.8 when the backfill and a trench, to prevent the pipe centerline displacement or damage to pipes, artificial fill on both sides of the pipe solid and should be carried out by pipeline on both sides at the same time, until the tube is above 0.5M, in the case of damaged pipes, frog-type ramming machine compacted. In the interface, anticorrosive insulation or cable around backfill should be fine.

3.9 after each layer of filling and tamping of backfill soil, should be carried out according to specifications cutting ring sampling, measure the density of dry soil; after you meet the requirements, then a layer of bedding.

3.10 trim look for dry: upon the completion of the fill, line level should be carried out, any more than the standard height, line level where less than the standard height, should fill soil.

3.11 rain, winter:

3.11.1 pit (Groove) or trench backfill should be carried out continuously, as soon as possible. Attention in construction of rainfall, Yuqian should be finished tamping layer or surface pressure of light, and make certain the slope for the benefit of excluding rain.

3.11.2 construction should be rain-proof measures to prevent surface water from entering pit (bad), so as to avoid slope collapse or destruction of soil.

3.11.3 backfill soil in winter construction of each layer's thickness of the bedding should be higher than room temperature reduces 20%~50%; frozen blocks of which shall not exceed the total volume of fill 15%; its size cannot be greater than 150mm. When filling, frozen soil should be evenly distributed by compaction.

3.11.4 before filling, clear ice and insulation on the basement; filling application are not frozen filling shop, its thickness should comply with the design requirements.

3.11.5 trench from end of pipe 0.5M range must not be used with frozen pieces of taxis refilling; indoor rooms, pit (Groove) or trench shall not be used with frozen soil backfill.

3.11.6 fill construction should be carried out continuously to prevent soil or layer from the cold, Frost measures should be timely.

4 quality criteria

4.1 project:

4.1.l base treatment must comply with the specification for design or construction requirements.

4.1.2 the backfill soil, must comply with the design or construction requirements.

4.1.3 the backfill is required compaction in layers. Sampling for the determination of compacted soil dry density of soil quality, the pass rate should not be less than 90%, not qualified dry density of soil quality the minimum value difference from the design value, should not be greater than 0.08g/cm3, and should not be set. Cutting ring sampling methods and quantity should be in order.

4.2 allowable deviation, as shown in table 1-7.

Backfill engineering tolerances in table 1-7

Serial number item tolerance (mm) test method

1

2 top level

Surface roughness +0-50

20 level or drawing a foot check

2m on foot and a wedge ruler check

5 finished product protection

5.1 when positioning axis standard pile, pile, standard and standard, Dragon door, filling Earth may not hit touch, nor shall rest on the Dragon door. Check these standards and should be repeated on a regular basis and are correct.

5.2 night-time construction, should arrange the construction sequence, equipped with adequate lighting, preventing the filling extra thick, non-auto dump directly into the tank.

5.3 base or ditch in-situ concrete should meet certain strength, will not be affected by the fill is damaged, it shall not be filled.

5.4 in the trench the pipeline, fertilizer tank from buildings of the pipeline shall be properly protected, then provides the backfill material shall not be damaged.

6 quality problems to be noticed

6.1 without the required determination of soil dry density of soil quality: each layer should be determined after tamping of backfill soil density, in line with design requirements before casting the top soil. Test report to indicate the soil types, test date, test results and test signature. Does not meet the design requirements site, proper treatment and re-inspection result.

6.2 backfill sunk: virtual bedding set thickness, or in winter when the larger blocks of frozen soil or compacted enough times, even missed ramming, pit (Groove) organic debris or falling soil cleanup does not clean at the end of, and apron in winter, construction of water into the cushion, caused by freezing and expansion. All these issues should seriously implement the specifications in the construction of the relevant provisions and to strictly check and found the problem corrected.

6.3 pipe lower compacted fill of false: the lower part of the piping should be according to the standard required to tamp the backfill soil, if RAM false leakage will cause the pipe below the empty, cause the pipeline break and leak.

6.4 backfill tamping pressure-tight: should be on proper watering in dry soil in dynamic compaction to be wet if too wet likewise tamping of backfill soil compacting there was "rubber" phenomenon, then it should be "rubber" dug up, again well be compacted soil.

7 quality records

This standard shall meet the following quality records:

7.l ground rod sounding record.

7.2 Foundation covert acceptance record.

7.3 of backfill soil test report.