Detailed construction scheme of flap gate

First, the general situation of construction:

The pile number of Taiping Moon Gate is 2+386. Taipingyue sluice is a sluice, which only plays an irrigation role. It is a reconstruction project, that is, demolishing old culverts and rebuilding new ones. Because the original culvert body is oblique to the levee, and the culvert body constructed according to the construction drawing is orthogonal to the levee, the reconstructed new culvert is arranged a little west of the original culvert position. Culvert is a cast-in-place concrete project, which consists of sluice chamber section, culvert body and outlet section. There are five culverts in total, with the overall dimension of 3.0 * 2.8m The earthwork excavation of culvert body is about 12000m3, and the earthwork required to drive the inner and outer cofferdams is about 8500m3. If the cofferdam is filled with earthwork excavated from culvert foundation, the earthwork filled by cofferdam cannot be used for culvert backfill, so the culvert backfill is convenient for soilless source, and the culvert backfill must meet the requirements of the specification, and it is best to use heavy silty loam and silty clay. Therefore, it is urgent to determine the soil source after construction.

Second, the project construction suggestions

Taiping Moon Gate is an important dike-crossing structure in Feixi section of Chaohu levee. Because the Taiping Moon Gate is located at the throat of the tributary of Chaohu Lake in the polder area, it is mainly responsible for drought relief and water release in the polder area. According to the geographical characteristics of this project, our project department organizes technicians to conduct on-site survey and collect hydrological data. Master the best construction period and construction scheme;

(1) does not affect the drought resistance in polder areas;

(2) Uncertainties of original site demolition and in-situ foundation treatment.

(3) The original sluice chamber is inclined to the levee, and the construction drawing shows that the sluice chamber is orthogonal to the levee, so the sluice foundation construction is not on the original basis, and the new sluice chamber must be staggered from the original sluice chamber.

In view of the above staggered sites, new culverts will be built and the construction period will be reasonably arranged.

Third, the construction preparation

Choose the best start time

According to the information provided in the tender documents, the average water level in Chaohu Lake for many years is 8.03 meters, and in recent years, the water level is mostly 8.5 ~ 9.5 meters ... The low tide period in Chaohu Lake generally begins in September. According to the flood control planning report of Chaohu Lake Basin, the flood level of Chaohu Lake is 10.8m in five years,10m in twenty years and1.6m in thirty years. According to the above data, the best construction period is from 10 to April of the following year, and the water level in Chaohu Lake is around 9.00 and below 9.00. During this period, the water level in Chaohu Lake is low, which is suitable for construction during this period. If you miss this period, it is not suitable for construction.

1. Equipped with capable full-time surveyors, familiar with the construction drawings, know the location of the site coordinate points, and choose measuring instruments such as rangefinder, theodolite and level that have passed the annual inspection by the metrological supervision institution to prepare for the measurement construction.

2. Before the construction of the principal part of the project, the full-time surveyors at the site should check the measurement accuracy of the reference point (line) together with the supervisor according to the reference point, reference line and leveling point provided by the supervision engineer, and lead them to the site according to the national surveying and mapping standards and the construction accuracy requirements of this project, and set up permanent control coordinate piles and horizontal foundation piles at the site. Protect permanent piles and establish engineering survey control network.

Four. Temporary cofferdam project

Because the living water elevation of Taipingyue sluice is 6.0, which is lower than the lowest water level in Chaohu Lake in recent years, and the potential in Taipingyue sluice is low, Taipingyue sluice is a sluice and only plays an irrigation role. There is a large pond with a low water level in the polder, and the top elevation of the cofferdam in the polder is low, while the water level at the edge of Chaohu Lake outside the polder is high, so the cofferdam (earth cofferdam) must be used in the import and export section. Cofferdams are also used as construction access roads during construction.

1, cofferdam section design

The water level from this year 10 to the next year 1 month is generally around 9.00~9.50. Considering the water level, wind and waves, safety and other factors, the top elevation of the outer cofferdam is 10.50m, the top width is 4.0m, and the inner and outer slopes are 1:4. A layer of rain cloth is laid on the water-facing side of the outer cofferdam considering wind and wave erosion, a wave wall with a height of 50cm is laid on the top and outside of the cofferdam, and a filter layer with a height of 1.0 m and a width of 0.5 m is laid on the inner slope angle of the outer cofferdam. Considering that there is no wind and waves in the inner cofferdam, the top height of the cofferdam is 8.50m, the width is 4.0m, and the internal and external slopes are 1: 4.

2, cofferdam section

Cross section of external cofferdam

Cross section of inner cofferdam

3, cofferdam filling

Organize cofferdam mechanical centralized filling immediately after entering the site, and the cofferdam construction period is planned to be completed in 7 working days.

(1) is filled by occupying space. Two excavators 1m3 borrow soil, and two bulldozers 120 level and roll. According to the construction conditions and time limit for a project on the construction site, single-sided filling method or double-sided filling method is adopted for filling.

(2) After the cofferdam is filled out of the water surface, soil shall be applied in layers, the thickness shall be controlled at 30cm, and the particle size of the soil shall be no more than 5cm. After each lamination test, lay the upper soil.

(3) The earth excavated by the emergency gate is used as the earth material for cofferdam filling. The water content of the soil material is controlled within the optimum water content range to ensure that the soil source is not soaked by rain or diving.

(4) Earthwork shall be compacted by bulldozer, and the compaction degree of earthwork after compaction shall be above 0.92.

(5) After filling to the top of the weir, it will be hardened with mud-bound gravel or Zhuangtai building slag.

4, cofferdam demolition

The cofferdam will be dismantled before the end of the project, and it is planned to dismantle all the cofferdams in five days. The above-water part of the removed earthwork is used for backfilling in the backfill area, and the underwater part is abandoned to the spoil ground or the place designated by the owner.

Cofferdam is dismantled by excavator and transported by car. Dig the water part first, and leave 50cm to dig and transport it together with the underwater part.

Chaohu bianwei

Culvert location

dam

dam

5. Breakdown method

All culverts and gates are excavated once, including culvert body, outlet section and inlet section. Construction of culvert body shall be carried out first, and then the construction of outlet section and inlet section shall be carried out after the dike is restored, so as to ensure the safety of Chaohu levee and the travel of surrounding residents.

6. Emergency measures

(1), the construction site is normal. There is an urgent need for excavators 1 set, forklifts 1 set, 2000 woven bags and 50 people.

(2) Drainage measures: When waterlogging occurs, ① temporary drainage facilities are added (pay attention to moving the water pump).

(3) Flood control and storm prevention measures: use sandbags and plastic sheets to build storm protection layer on the water-facing slope, and throw stones outside sandbags to build wave retaining wall.

(4) When the weather and water level are abnormal, the field personnel will be on duty in turn for 24 hours, and the abnormality will be handled and reported in time to ensure the safety of the levee.

Verb (abbreviation for verb) earthworks

Foundation pit excavation and earthwork backfilling shall be carried out with 1m3 backhoe excavator in cooperation with dump trucks and local agricultural vehicles, and the area near the building structure and narrow corners shall be tamped with frog rammer or human rammer.

1, earthwork excavation

(1), before the earthwork excavation of foundation pit, set elevation control piles according to the requirements of drawings, and do a good job of positioning and setting out according to the excavation line shown in the drawings.

(2) Earthwork excavation of foundation pit shall be carried out by layers and sections in turn, and drainage ditches shall be set up step by step for layered excavation. 20cm thick protective layer should be reserved for mechanical excavation at the bottom of foundation pit, and then artificial block excavation should be adopted before foundation construction. The unusable earthwork should be sent to the spoil ground designated by the supervision engineer.

(3) Earthwork excavation shall be carried out in layers and sections from top to bottom. Top-down or upside-down excavation is strictly prohibited. During construction, a certain slope potential should be prepared at any time to facilitate drainage, and water accumulation in the slope stability range should be avoided during excavation. Dig a drainage ditch on the reserved working face 0.7 meters away from the bottom sideline on both sides of the building, dig a sump in the proper position of the drainage ditch, and discharge the water out of the construction area with a pump.

(4) The embankment soil in this section is heavy silty loam with high sand content. Considering the construction safety, two construction platforms are set for foundation pit excavation. Put the slope 1:3 according to the specification requirements, set up a 2.0m-wide construction platform at the elevation of 8.5m, and set up a 2.0m-wide construction platform at the elevation of 1 1.5m, and pile soil is not allowed within 5.0m of the dike top, so as to ensure slope stability and prevent landslide.

2, earthwork backfill

Earth compaction of foundation pit shall be leveled by 59KW bulldozer, and rolled by crawler wheel of bulldozer. The adjacent areas and narrow corners of the building structure should be tamped by frog rammer or human rammer to ensure the compactness meets the requirements of design drawings.

Six, template engineering

1, overview

The concrete engineering buildings shown in the bidding documents of this project include concrete, reinforced concrete, precast concrete and other items of permanent engineering buildings such as culverts and gates.

According to the characteristics and actual requirements of the divisional works, the specific construction sequence of the drainage culvert works is as follows:

2, template engineering construction

3. Design of template system

The formwork of this project adopts wooden formwork. The formwork shall be made of high-quality wood, the thickness of formwork panel shall not be less than 10mm, and the surface of formwork shall be as smooth as possible, without surface defects such as pits and wrinkles.

4, template assembly

The maximum size of a single template is 1500×300mm. Stick sponge strips at the joints of the formwork to prevent slurry leakage. Template and the edge of the template with φ 12mm connection, L= 140. The bracket is provided with a fastener foot tube, and the inside of the formwork is coated with an isolation agent to maintain the color sense of the molded concrete.

5, template support

In order to ensure that the formwork structure has enough strength to meet the lateral pressure and vibration force of concrete pouring and vibrating, the back of the formwork needs to be reinforced, with the horizontal spacing of 800mm and the longitudinal spacing of1000 mm. In order to prevent the formwork from moving, two anchor piles are driven every 1000 mm, and the middle is locked with short steel pipes.

6, template removal

When dismantling the formwork, in addition to observing the provisions of the construction drawings, the following provisions shall also be observed:

1 Non-load-bearing side formwork shall be removed only after the concrete strength reaches the surface and the edges and corners are not damaged by formwork removal.

2 pier, wall, column side template removal should be in the concrete strength is not less than 3.5Mpa, can be removed.

3 bottom die removal should be carried out after the concrete strength reaches the requirements in the table below.

Table 3- 1 Demolition standard of bottom die

Structure type Structure span (m) Percentage (%) according to the standard value of design concrete strength.

Plate ≤ 2 50

≥2,≤8 75

>8 100

Beam ≤ 8 75

>8 100

Cantilever member ≤ 2 75

>2 100

Seven, steel structure engineering construction

1, steel material control

The steel bars used in this project are products produced by Maanshan Iron and Steel Company. Reinforcement must have a quality guarantee or original test report when entering the site. The surface of the steel bar is marked by the manufacturer, and each bundle has a relative furnace (batch) number, which shall be submitted to the representative of the construction unit and the supervision engineer for inspection. Samples shall be taken on site as required and sent to qualified laboratories for tensile strength, elongation and cold bending tests. Unqualified steel bars are strictly prohibited.

2, steel processing

(1) The surface of reinforcement shall be clean and free from damage, and paint pollution and rust shall be removed before use. Granular or flaky old rusty steel bars shall not be used.

(2) Steel bars shall be straight without local bending, and the straightening of steel bars shall meet the following requirements:

1) When straightening steel bars by cold drawing method, the cold drawing rate of Grade I steel bars should not be greater than 4%; The cold-drawn rate of secondary and tertiary steel bars should not be greater than 65438 0%.

2) The processing size of steel bars shall meet the requirements of construction drawings, and the allowable deviation of steel bars after processing shall not exceed the values in Table 3-2 and Table 3-3.

Table 3-2 Stirrups made of round steel and hook length at the end.

Diameter of stirrup and rebar (mm)