u现浇重力式钢筋混凝土挡土墙

1、Good is good, but better carries it.精益求精，善益求善。u现浇重力式钢筋混凝土挡土墙现浇重力式钢筋混凝土挡土墙现浇重力式钢筋混凝土挡土墙Cast in place gravity reinforced concrete retaining wallConstruction technology standards (VIII, 124)1 scope of applicationThis standard is applicable to the construction of cast in place reinforced concrete retain

2、ing wall for highway, urban road and bridge.2 construction preparation2.1 materials2.1.1 cement: generally use Portland cement, ordinary portland cement, slag Portland cement. Cement approach should have product certification and inspection report, deal with the strength, stability and other perform

3、ance indicators after entering the necessary sampling reexamination, the quality must be consistent with current national standards "Portland cement and ordinary portland cement" GB175. When there is any doubt about the quality of the cement or the cement is out of production for more than

4、 three months, the re examination must be conducted before use and the result shall be used as a result of the retest. Different kinds of cement shall not be used in combination.2.1.2 sand: generally use medium and coarse sand. Sand varieties, quality should be consistent with current national stand

5、ard "technical specification for construction of highway bridges and culverts" JTJ041, after entering the country in accordance with the provisions of the current standard "test methods of aggregate for Highway Engineering" JTJ058 sampling test.2.1.3: we should use the hard stone

6、 or pebble gravel, should according to the different situations of origin, category, processing methods and specifications, in accordance with the provisions of the current national standard "test methods of aggregate for Highway Engineering" JTJ058 batch inspection, the quality should be

7、consistent with current national standard "highway bridge culvert construction technology standard" JGJ63 regulations.2.1.4 water: suitable for drinking water. When using other water sources, the water quality should be in line with the current national standard "water standard for co

8、ncrete mixing", JGJ63.2.1.5 steel: steel shall have quality certificate and test report form; variety, level, specifications of steel bars should comply with the design requirements; the reinforced approach should be selected to do sample test of mechanical properties, the quality must be consi

9、stent with existing national standards, "the reinforcement of concrete hot rolled round bar" GB13013, "the reinforcement of concrete hot rolled ribbed bar" GB1499 and "GB13788" cold rolled ribbed steel bars and other provisions.Chemical analysis or other special tests s

10、hall be carried out when the steel bars are found to be brittle, poor in weldability or mechanical properties are abnormal.2.1.6 welding electrode: the selected electrode should be matched with the reinforced base material, and the approach should have a certificate.2.1.7 admixture: additives should

11、 be product manuals, factory inspection reports and certificate of quality, performance testing report, the content of harmful substances should be tested by the corresponding level of testing issued by the testing department. Approach shall be re examined by sampling, and the suitability of admixtu

12、re and cement shall be checked. The quality and application technology of the admixture shall be in line with the current national standard "concrete admixture", GB8076 and regulations on the application of concrete admixtures, GB50119.2.1.8 admixture: the admixture shall have the factory

13、certificate or quality certificate and the quality inspection report provided by the statutory inspection unit, and shall be re examined after the approach. The quality of the admixture shall be in accordance with the current relevant standards of the state, and the amount of admixture shall be dete

14、rmined by experiment.2.1.9 embedded parts specification and material shall comply with the design requirements.2.2 implements and equipment2.2.1 machinery: concrete mixer, concrete pump (pump by using), concrete mixer truck, hoisting machine, cutting machine, bending machine, welding machine, crane,

15、 dump trucks, scales, mobile generator.2.2.2 tools: steel plate, trolley, scraper, level, foot, shovel, vibrator and so on.2.3 operating conditions2.3.1 the main structure of the bridge is completed or the elevation of the subgrade is higher than the elevation of the foundation of the retaining wall

16、, and the compactness can meet the design requirements before construction can be carried out.2.3.2 base acceptance and complete the hidden inspection procedures.2.4 technical preparation2.4.1 the road and bridge design drawings shall be checked before construction, and the surveying personnel shall

17、 calculate the retaining wall plane and Gao Cheng control survey and construction survey according to the construction line and the Gao Cheng control point of the road, the bridge construction line and the control point.2.4.2 complete breakdown of commencement report, concrete test, material inspect

18、ion and examination and approval procedures and requirements of the owners, supervision of technical documents.2.4.3 preparation of concrete retaining wall construction program has been approved, and related personnel safety technical disclosure.3 operation process3.1 processMeasurement line? Cushio

19、n construction production and installation of reinforced foundation? a foundation template pouring concrete foundation? production and installation of reinforced wall and embedded parts? Supported wall template? Pouring concrete wall and health?3.2 operation method3.2.1 measuring and laying out: acc

20、ording to construction drawings and coordinate points, release the retaining wall center line, the basic plane position line and vertical height line, and do the plane and elevation control points.Construction of 3.2.2 cushionThe strength of the 3.2.2.1 cushion concrete shall comply with the design

21、requirements.When the bottom of the 3.2.2.2 cushion is not at the same elevation, the construction shall be carried out in accordance with the first deep and the shallow order.After the completion of the construction of 3.2.2.3 cushion, the design elevation shall be checked, and the axis of the wall

22、, the dimension dimension line and the reinforcing bar control line shall be ejected according to the design drawings and the middle line of the retaining wall.Fabrication and installation of 3.2.3 base reinforcement3.2.3.1 shall be subject to re examination, verification, sampling and inspection of

23、 the steel in accordance with the relevant provisions, and may be used after qualification.3.2.3.2 reinforcement shall be stored according to variety specification, batch number and classification, and shall not be mixed. There are serious corrosion, hemp pit, split, sand, interlayer, oil and other

24、reinforcement may not be used.3.2.3.3 the reinforcement should be cleaned before binding, and the main ribs and the spacing of the tendons should be drawn with chalk on the cushion. According to the first row spacing, placed reinforcement, reinforcement distribution. Embedded parts and preformed hol

25、e should be combined with the installation etc.3.2.3.4 binding steel bar usually with the buckle or eight button, except for the outer two tendons intersection point should be all tied outside, and the other points can be staggered binding.3.2.3.5 in the steel and template pad cushion block, spacing

26、 is not greater than 1.5m, the protective layer thickness should comply with the design requirements.The 3.2.3.6 cushion block is usually made of cement mortar, and the thickness of the cushion block should be the same as the thickness of the protective layer. The embedded fire wire is embedded in t

27、he cushion block or the plastic card is used to guarantee the thickness of the protective layer.3.2.3.7 steel connections shall be welded or mechanically connected.3.2.3.8 in binding double layer steel wire mesh, should set enough strength of support feet, in order to ensure the accurate positioning

28、 of steel mesh. Stable and firm, not loose or deformed when pouring concrete.3.2.3.9 molding steel welding, no rust, grease before welding; weld shall not undercut, crack, slag, the skin should be cleaned up.3.2.4 foundation formworkThe 3.2.4.1 formwork shall have enough strength, stiffness and stab

29、ility to withstand the impact of concrete and the lateral pressure of concrete.3.2.4.2 formwork shall ensure the shape, size and position of the retaining wall accurately, and be easy to disassemble. The joint of the formwork shall be tight and shall not leak or stagger the platform.3.2.4.3 mold rel

30、ease agent should be painted evenly, shall not pollute the steel bar.The 3.2.4.4 axis, the template line is completed, should be dealt with pre screening procedures.3.2.4.5 template after installation, should check the reserved hole and embedment position, meet the design requirements, can be carrie

31、d out under the step.When the 3.2.4.6 formwork is supported, the mouth of the template should be horizontal support first and then be fixed by diagonal brace.3.2.5 pouring foundation concrete3.2.5.1 the concrete shall be checked and accepted before the concrete is poured. Template installation is fi

32、rm, smooth, tight gap, debris should be cleared, excluding the water, and go through the pre screening procedures.3.2.5.2 concrete mix shall comply with the design strength requirements.3.2.5.3 concrete pouring, free fall is generally not greater than 2m, when larger than 2m, the use of pipe or chut

33、e transport.3.2.5.4 cast in place gravity reinforced concrete retaining walls shall be determined according to the concrete form and size of retaining walls. When the foundation and wall are arranged in stages, the following requirements shall be met:(1) the foundation concrete strength above 2.5MPa

34、 can support partner wall wall template.(2) the foundation concrete shall be laid in the foundation for supporting and locating the wall plate.3.2.5.5 concrete vibration(1) the concrete foundation should adopt the plug-in vibrator vibrated, when the vibrating rod inserted in a straight line ranks, 1

35、.5 times the distance shall not exceed the vibrating rod radius; if the plum blossom type ranks insert, moving distance shall not exceed 1.75 times the radius of action; vibration when the vibrator is not directly put in the bar.(2) vibration to concrete is no longer sinking, no significant bubbles,

36、 the surface is flat and consistent, began to emerge cement paste for the degree. If the surface water layer is found, the cause should be analyzed and solved.(3) the vibrating bar should be kept 50 to lOOmm distance from the template. The parts that are not suitable for vibration should be artifici

37、ally vibrated.(4) concrete shall be divided into layers and the thickness shall not exceed 300mm. Each layer of concrete pouring shall not be interrupted; should the first layer of concrete vibration has not been before the initial setting of the secondary layer, concrete pouring and tamping. When v

38、ibrating the secondary concrete, the vibrating bar shall be inserted into the front layer from 50 to 100mm.With the installation requirements of article 3.2.3 of this standard according to related regulations of the construction production of 3.2.6 wall reinforcement and embedded parts.3.2.7 vertica

39、l wall formworkAccording to the position of 3.2.7.1 line installation wall template, the template should be firmly supported, mouth and floor timbers, accounted for in the die with wooden support, to prevent the template loosening, run mode in pouring concrete.According to the 3.2.7.2 template desig

40、n after assembling the good side of the template and according to the position of line in place, and then install the rod or brace, mounting sleeve and wall bolt, wall bolt specifications and spacing should be clearly defined in the template design.3.2.7.3 clean the mess in the wall,Then install the

41、 other side of the template, adjust the support to the template vertically, tighten the pull bolts.3.2.7.4 template isolation agent should be painted evenly, shall not pollute the steel bar.3.2.7.5 template after the installation is complete, check the fastener bolt securely, and under the export te

42、mplate patchwork is tight, for pre screening procedures.3.2.8 pouring wall concrete3.2.8.1 wall before concrete pouring, pouring in the bottom Jiecha first uniform thickness of 15 20mm and the wall of the same strength grade of concrete reduced stone concrete.3.2.8.2 concrete shall be divided into l

43、ayers according to specifications, vibrating and compacted, and the layer thickness shall be no more than 300mm. The concrete blanking points shall be dispersed and arranged. The wall shall be continuously poured, and the interval between each layer shall not exceed the initial setting time of the c

44、oncrete. The wall concrete construction joints shall be located at the design expansion joint.3.2.8.3 the concrete pouring height should be symmetrically and evenly poured on both sides of the tunnel opening. The vibrating bar is more than 300mm from the hole edge to prevent the hole from shifting a

45、nd deforming.3.2.8.4 vibrated concrete pouring is completed, will be thrown out of the mouth of sorting out steel, wood trowel according to the design elevation of the line of control level on the wall.3.2.8.5 other construction of wall concrete can refer to the construction of this standard 3.2.5.3

46、.2.9 concrete curing3.2.9.1 after the completion of concrete pouring should be covered and watered within 12h, the number of watering should be adequate to keep concrete wet state, the maintenance period is generally less than 7d, according to the air temperature and humidity, and mixed with cement

47、and admixture, appropriate extension.3.2.9.2 of large volume concrete retaining wall maintenance, according to climatic conditions to take control measures, to control the temperature in the design requirements in.3.2.10 template removal3.2.10.1 when the strength of concrete reaches more than 2.5MPa

48、, the side formwork can be removed.3.2.10.2 first release and remove the pull rod by section, and it should not be too long for one release. Not allowed to strike with heavy strokes or strong twisting.3.2.IO.3 block removal of formwork, demolition, pay attention to protect the wall, to prevent damag

49、e.3.2.10.4 the template and support should be repaired, sorted and stored properly after dismantling.3.3 seasonal construction3.3.1 construction period3.3.1.1 concrete construction must be ready to cover, block the rain and discharge water, in order to prevent rain soaking and erosion, affecting the

50、 quality of concrete.During the 3.3.1.2 period of construction, water content of sandstone varies greatly, measured in time, and adjust the construction mix, ensure the quality of concrete.3.3.1.3 concrete should understand the weather changes before opening, and try to avoid pouring concrete when i

51、t rains. In case of rain, the concrete should be covered in a timely manner to prevent the rain from pouring.3.3.1.4 water soluble mold release template, should take effective measures to prevent the rain directly erosion and fall off, affecting the release and surface quality of concrete.3.3.1.5 in

52、 the pouring of concrete, if the rain stops suddenly, time is too long, more than the initial setting time of concrete, should be treated as construction joint. When the construction continues after rain, the joints shall be treated with technology before pouring.3.3.2 winter construction3.3.2.1 the winter construction of concrete can be common cement, Portland cement, controlling water cement ratio is less than or equal to O.5, and mixed with antifreeze.3.3.2.2 concrete shall be clear of snow and ice on the formwork before pouring. When the pump concrete pump pipe, insulation