02 pipe installation 1
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1
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4
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5
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When excavating the pipe trench, the structure of the soil below shall not be damaged
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When various underground facilities or cultural relics are found during trench excavation, protective measures shall be taken and timely reported to Party A and relevant units for treatment
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According to the measured center line, the elevation control pile shall set out the center line and elevation point of the pipe trench before excavating the trench
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2
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3
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After the sewage pipeline is completed in sections, the rainwater pipeline shall be excavated
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2
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When it is inconvenient to carry out at the same time, step connection shall be reserved
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The allowable deviation of inspection well shall comply with: Allowable deviation (mm) shaft size length, width ± 20 diameter ± 20 elevation difference between well cover and pavement non pavement + 20 pavement is consistent with road regulations, well bottom elevation ± 1010, reinforced concrete cover plate installation, reinforced concrete cover plate shall be lifted, handled and stacked according to the design lifting point, and shall not be placed in reverse
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8
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After the cover plate is in place, the staggering of the adjacent plate bottom shall not be greater than 10mm, and the length of the plate end pressing the wall, with the allowable deviation of ± 10mm
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The steps of the concrete shaft wall shall be installed during cast-in-situ
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05 inspection well 1
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If there is no other appropriate method for drainage, a safe and reliable aqueduct or crossover shall be erected
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after the pipe joint is placed on the foundation, it shall be corrected and straightened
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7
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The pipe orifice of the inspection well connected to the circular pipe shall be flush with the inner wall of the well, and the place where the pipe passes through the well wall shall be tight without water leakage
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During the closed water test of the pipeline, the test pipe sections shall meet the following requirements: 1) the appearance quality of the pipeline inspection well has been accepted
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The backfilling around the inspection well shall be carried out at the same time as the backfilling of the pipeline trench
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The concrete sewage pipe can be backfilled after the closed water test is completed and the acceptance records of concealed works are handled
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7
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9
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D
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During step installation, the surrounding pores shall be sealed with 1:2 cement mortar
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First make the foundation and strictly control the elevation
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4
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when the crane is running down the pipe, the position of the crane shall not affect the stability of the trench slope
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After the mechanical excavation depth is about 10cm, it shall be manually excavated to the design elevation
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During backfilling, the original soil shall be used for backfilling
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The triangular mortar at the slab joint and slab end shall be filled and plastered with cement mortar
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3
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2
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9
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After the steps are installed, they shall not be trampled when the masonry mortar or concrete does not reach the specified compressive strength
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Over excavation is strictly prohibited, and the allowable deviation of trench bottom elevation shall be controlled within 0-30mm
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Due to the unknown geological data of the project, during the excavation of pipe trench, the soil quality, groundwater level and original pipeline shall be known in time
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The upper plane should be kept clean
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Before backfilling, the pipeline shall be subject to tightness test by closed water method, and the test pipe sections shall be separated according to the well spacing
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Key points for quality control of pipeline laying 1
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6
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5
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The local over excavation part shall be backfilled and compacted
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Until the end of observation, make up water to the test pipe section continuously to keep the test water head constant
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7
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The virtual paving thickness of compaction tools (CM) roller 20-30 vibratory roller ≤ 406
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03 closed water test according to the specification requirements, the sewage pipeline shall be subject to closed water test
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2) The pipeline is not backfilled and there is no ponding in the trench
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It can be used only after passing the appraisal
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Pipe laying: A
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The minimum thickness shall be determined according to the specification of the actual machinery and the design bearing capacity of the pipeline
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3
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The allowable deviation of groove bottom elevation is ± 20mm
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The sewage pipeline shall be constructed first
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The excavation quality of the trench shall meet the following requirements: the net width on each side of the trench centerline shall not be less than half of the excavation width at the bottom of the pipeline trench
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The materials and thickness of layered backfilling shall be constructed according to the requirements of the design drawings
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The excavation depth of trench shall be strictly controlled according to the base elevation
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The water content of backfill should be controlled close to the optimum water content according to the compaction tools used
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Gantry and manual hoist can be used to slowly lift both ends of the pipe joint and move it on the foundation
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8
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The virtual paving thickness of each layer of backfill shall be determined according to the compaction tools and requirements
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If the groove is supported, it shall not collide with the groove wall support and the pipe under the groove, so as to prevent the pipe laying rope from breaking or sudden impact from damaging the foundation
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When backfilling other parts, they shall be evenly filled into the groove and shall not be pushed in intensively
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3) The pipe section not tested in the inspection well shall be blocked without water seepage
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2
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Cut off the original drainage ditch or drainage pipeline through the trench
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If protection should be taken, protection measures shall be taken in time
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The closed water test shall be carried out according to the following procedures: 1) the soaking time after the test pipe section is filled with water shall not be less than 24h
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For general compaction tools, the paving thickness can be selected according to the table below
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After the inspection well is built or installed to the specified elevation, the well ring shall be poured or installed in time and the well cover shall be covered
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Within 50cm around the wellhead of the inspection well, lime flyash soil shall be backfilled and compacted in layers to the road subbase, and then No
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3
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The well bottom foundation shall be poured simultaneously with the pipeline foundation
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When using the excavator for construction, the 30cm thick soil layer can be reserved
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When the earthwork is excavated close to the design elevation, an elevation control pile shall be driven in the trench to control the excavation depth and prevent too shallow or over excavation
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Before cover plate installation, the wall top shall be cleaned, watered and then spread slurry for installation; The width of the slab joint for the installation of the cover plate shall be uniform, and it shall be handled with care during hoisting without collision
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During excavation, dewatering shall be carried out according to the groundwater level, and the bottom of the tank shall not be soaked by water.
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2
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The observation time of water seepage shall not be less than 30min
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3) When the test water head reaches the specified water head, start timing and observe the water seepage of the pipeline
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the pipe shall be lowered by crane, starting from one end of the two inspection wells, and the pipe shall slowly fall to the foundation
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When heavy compaction machinery is used for compaction or heavy vehicles are driving on the backfill, there shall be a certain thickness of compacted backfill above the top of the pipeline
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The size of inspection well meets the design requirements
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before pipe laying, conduct appearance inspection on the pipe to see whether the pipe meets the design requirements
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B
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The compaction times of each layer of backfill shall be determined by field test according to the required compactness, compaction tools, virtual paving thickness and water content
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25 cement concrete shall be poured 20cm under the asphalt concrete surface for reinforcement
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The plastering of inner and outer walls of masonry manhole shall be compacted in layers
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During well chamber masonry, steps shall be installed at the same time, and the position shall be accurate
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During trench backfilling, bricks, stones, wood blocks and other sundries shall be removed
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During correction, a certain gap (generally 10mm) shall be reserved between pipe interfaces
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The excavation section of pipeline trench shall be determined according to the drawing design
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6
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4) The measured water seepage shall be calculated according to the formula q = w / T · L, where Q – measured water seepage (L / min) w – make-up water (L) T – measured water seepage observation time (min) l – length of experimental pipe section (m) 04 pipe trench backfilling 1
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The trench soil shall be stacked outside the pipeline safety line for pipeline installation, concrete pouring, etc
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2) The test water head shall be calculated by adding 2m to the inner wall of the upstream pipe top of the test section
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If the concrete foundation cannot be poured immediately after manual excavation, 15cm thick soil layer can be reserved at the bottom of the trench
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Source: in case of infringement, please contact to delete 01 trench excavation
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The backfilling materials on both sides of the pipeline and within 50cm above the pipe top shall be transported into the groove symmetrically from both sides of the groove and shall not be directly thrown on the pipeline
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Within 500mm from the groove bottom to the pipe top, there shall be no bricks, stones and other hard blocks greater than 50mm in the backfilled soil
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It is strictly prohibited to be too high and too low
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For the excavated pipeline trench, warning signs shall be set in time and closed for management to prevent accidents
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C
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8
All excavated earthwork shall be transported out
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When the crane is working near the high-voltage transmission line, the safe distance between the crane and the line shall comply with the provisions of the local power management department
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The chute in the inspection well should be built at the same time with the well wall, the surface should be compacted and troweled with mortar in layers, and the chute should be connected with the bottom of upstream and downstream pipes
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4
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Excavation shall be carried out from upstream to downstream
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For the quicksand layer, the following construction methods can be adopted: 5
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1
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