Thursday, October 13, 2016

Lime soil Foundation construction technology

1 scope
This technology is applicable to general industry and civil architecture Foundation, base Groove to assessment, sewer, an outdoor stage, indoor and apron and lime soil Foundation (cushion).
2 construction preparation
2.1 materials and equipment:
2.1.1: advised to give priority to the use of trench dug in the dirt, but must not contain organic impurities, prior to screening, its diameter is not more than 15mm. Water content should meet the requirements.
2.1.2 lime: the ash or lime; should be fully cured before using sift shall not contain size block of quicklime is greater than 5mm, or contains too much water.
2.1.3 equipment: General should have wooden Rammer, frog or diesel ramming machines, trolleys, sieve (diameter 6~10MM and 16~20mm two), standard bucket, on foot, rake, a flat shovel, hose, small lines and Pocket rule.
2.2 operating conditions:
2.2.1 pit (Groove) in front of the shop dust study inspection must be brazed, and according to the design and exploration Department Foundation has been processed, through hidden procedures.
2.2.2 base side dust must be based, check basement walls and underground water-proof layer, protective layer, damage should be repaired, when hidden procedures. Poured concrete foundation walls and beams shall meet the requirements of strength, not hit damage concrete.
2.2.3 the local water level higher than the pit (notch) at the end of construction should take measures to reduce groundwater drainage or, enable the groundwater level was maintained at below the 0.5M, shall not be affected by water immersion in a 3D.
2.2.4 engineering should be based on compaction factor characteristics, design, and construction types, soil conditions, rational determination of soil water content control. Thickness of the spreading of lime-soil compaction and consolidation parameters such as playing a few times. Key lime filling its parameters should be determined by compaction tests.
2.2.5 house dust and tunnel dust, should be completed on water pipe installation or after the trench wall reinforcement measures such as, and. On the sewer, tank, flooring and water clean or debris, waste and other organic matter.
2.2.6 construction, as a sign of good levels of elevation. As in the pit (Groove) or trench on every 3M on the slopes of nail dust on flat wood stick, indoors and on playing on the Wall beside the apron level or nail on the floor good elevation control stakes.
3 operational processes
3.1 process:
Testing soil and lime powder and sift the quality of lime-flyash soil mixing bottom clearing layered spread dust

Dynamic compaction-compacting leveling acceptance
3.2 first check type and soil quality and lime quality meets the standard requirements and then sift. If it is made of gray boring Hydrated lime, 6~10MM sieve, sieve, is lime can be used; using 16~20mm soil sieve, sift, shall ensure that the size requirements.
3.3 dust mix: volume ratio of mixture ratio of lime application, apart from special design requirements, typically 2:8 or 3:7. Bedding dust must be standard, strictly control the mixing ratio. Uniform mix must be timely, with at least twice, mix good lime color should be consistent.
3.4 lime soil construction, should be appropriately controlled moisture content. Site inspection methods are: dust with her hands clenched, two-finger pinch light is broken. Too much water or soil is low, should be allowed to dry soaking wet.
3.5 pit (Groove) or base by the end of the surface should be cleaned. Especially trough falls of tilled soil, wind-blown leaves, Wood scraps of paper, plastic bags and other refuse clutter.
3.6 tiered Pu lime: lime casting thickness of each, according to the different construction methods and selection according to table 2-l.
Lime's largest virtual shop thickness table 2-1
Types of compactor weight (kg) empty paving thickness (mm) remarks
1 wooden Rammer 40~80 200~250 human ramming and landed high 400~500mm, a RAM and a half RAM
2 light tamping Rammer, diesel -200~250 frog ramming machine
3 roller 6~10T 200~300 double

Wooden rake after every casting leveling, and pit (Groove) on the side wall of wood bent or correspond to the standard log check on the floor.
3.7 dynamic compaction-compacting: RAM (pressure) times should be designed according to the needs of dry soil density or field test determined that normally no less than three times. Artificial ramming a RAM and a half RAM, RAM RAM, connected to the line, vertical and horizontal cross.
3.8 when the lime soil construction, not in the corner, under the Foundation and load-bearing wall between Windows by Cha, Cha of the upper and lower layers of lime-soil compaction distance shall not be less than 500mm.
3.9-ash backfill each RAM (pressure) after real, should be based on norms of the cutting ring sampling, measure the density of dust, when you meet the design requirements, to make the casting of a layer of dust on it.
Penetration Tester check the dust mass, field tests should be conducted to determine the specific requirements for penetration. Ring cutter soil compaction factor identified by dy, typically 0.93~0.95 either according to the provisions of the table 2-2.
Table 2-2 of the density of lime-soil quality standards
Kinds of lime soil minimum mass density (g/cm3)
1
2
3 light loam
Clay
Clay 1.55
1.50
1.45

3.10 leveling and acceptance: dust the top layer is complete, pull or on foot elevation and flatness check, super high levelled with a spade; low timely fill dirt.
3.11 rain, winter:
3.11.1 pit (Groove) or trench dirt backfill should be carried out continuously, as soon as possible. Should prevent surface water into the slot in the construction pit, so as not to collapse or damage on the base of the slope.
3.11.2 rainy day when rain or drainage measures should be taken. Has just finished playing or not yet compacted lime-soil compaction, such as being caught in the rain soaked, stagnant water and loose dirt should be removed, and to make up for a new lime-soil compacted, wet dust should be dry, dynamic compaction-compacting.
3.11.3 winter lime-soil material shall not contain blocks of frozen soil, to do with the sieve, mix with, with, with cover, seriously implement the provisions, then rub and compaction in layers. In the loose soil can be allowed to sprinkle salt. Temperature below-10 , not construction. And a winter program.
4 quality criteria
4.1 project:
4.1.l the soil must meet the design requirements of the base.
4.1.2 dust dry soil density or penetration must meet the requirements of specification for design and construction.
4.2 Basic project
4.2.1 the ingredients right, mix evenly thickness of layered virtual shop meet the requirements, dynamic compaction-compacting, no loose skin on the surface.
4.2.2 Cha and Cha. Cha place hierarchy, the method correctly, Cha-dense and smooth.
4.3 allowable deviation, as shown in table 2-3.
Lime soil Foundation tolerance table 2-3
Project tolerance (mm) test method
1
2 top level
Surface flatness of ± 15
15 level or cable and check
2m on foot and wedged feeler Gage check

5 finished product protection
5.1 construction should pay attention to properly protect the spud, axis and displacement for preventing collisions and should be repeated frequently.
5.2 Foundation, foundation walls and underground waterproofing layer, protective layer, and reached through the foundation wall of the pipeline shall be protected to prevent collisions when the backfill dirt or damage.
5.3 night-time construction, should arrange the construction sequence, be equipped with adequate lighting facilities, preventing the filling thick or mix errors.
5.4 grey soil after the time of basic construction and floor construction or temporary cover, preventing the sprinkling rain.
6 quality problems to be noticed
6.1 is not required for the determination of dry soil mass density: lime-soil backfill during construction, remember that each layer of lime-soil compacted after determining dry mass density, meets those requirements, to top of the casting dust. And included in the test report, indicating the species, soil mix, testing dates, number of layers (steps), conclusions, test signature, and so on. Density meets the design requirements of the position at the end, should have the treatment and re-inspection result.
6.2 to reserve, answered Cha does not meet the requirements: lime soil construction in strict implementation of the provisions of the Cha. When lime-soil Foundation level is not at the same time, shall be made in step, upper and lower dust Cha distance shall not be less than 500mm. Cha Cha should be vertically aligned.
6.3 lime block curing bad: carefully sift grain too large, causing particles water cure volume expansion, will transform the upper layer, base arch cracked. Consolidation will seriously Hydrated lime, the screening requirements.
6.4 dust mixture ratio is not accurate: no seriously standard bucket and Hydrated lime for soil, or to spend lime powder sprinkled on the soil surface, mixing is not uniform, the result will be inconsistent lime soil base hard and soft, dry soil density difference too much. Should do a measurement.
6.5 dirt surface too large, resulting in concrete layer is too thick or too thin on the ground, causing ground cracking and hollowing. Carefully check the dirt surface elevation and flatness.
6.6 rain, winter can't do dirt work, with due regard to modify the design. You should make good rainy season, the winter programme; construction construction plan in the technical measures to prevent lime-soil quality rework accidents such as blisters, frost heave.
7 quality records
This standard shall meet the following quality records;
7.1 the construction engineering geology investigation report of construction sites within the region.
7.2 ground rod sounding record.
7.3 ground covert acceptance record.
7.4 lime-soil test report.

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