Construction scheme of cast-in-place concrete lattice slope protection
I. Overview of the Project
My contract section is the TJ-XX contract section of XX expressway, with mileage pile number k11+000 ~ k117+325, with a total length of 6.325km. When the filling slope height H≥5m, the excavation slope height ≥8m. Second, the construction machinery and personnel
1, main construction machinery and equipment
List of main construction machinery and equipment
2. Supervisors: subgrade supervision engineer 1 name, survey supervision engineer 1 name, test supervision engineer 1 name, supervisor 1 name.
3. Staffing of the project department: chief engineer 1 person, deputy production manager 1 person, section chief 1 person, technician 1 person, experimenter 1 person, foreman 1 person, 5 template workers and vibrator workers. Third, the construction preparation
1. Before the construction of cast-in-place concrete lining arch, the earthwork construction of this section of subgrade must be completed. Firstly, the boundary line of subgrade is measured, and the subgrade slope is repaired by excavator combined with manual work. When trimming the slope, use slope scale guy to trim it, and the slope after trimming shall not be greater than the design value. After the trimmed slope is accepted by the supervision engineer, the next procedure can be carried out.
2. Before the foundation starts construction, submit the construction organization design and commencement report of this project to the supervision engineer, and start construction only after it is approved by the supervision engineer.
3. Survey and lofting: determine the skeleton foundation details according to the design requirements, and carry out the construction according to the plane position, elevation and geometric dimensions designed by the drawings in combination with manual excavation of the foundation pit.
4, the construction site electricity generator is used to generate electricity.
5. Set up sub-project construction signs at the site, indicating the main technical director, on-site quality management personnel, test and inspection personnel, safety director, main construction technology and quality standards, so as to guide the construction. And establish a safety production card.
Four. Temporary drainage scheme
Because my contract section mainly belongs to the expansive soil area, strict measures should be taken to prevent the slope and foundation pit from being washed by rain during construction. Therefore, before construction, facilities such as temporary intercepting ditch and water retaining bank should be prepared to prevent rain from washing the slope, and ponchos should be prepared to prevent sudden rain from washing the loose concrete surface during construction.
Verb (abbreviation of verb) construction scheme of cast-in-place concrete grid skeleton
1, construction lofting
Cast-in-place concrete lattice skeleton project should be constructed in sections and set out in sections. According to the centerline of subgrade and the slope angle (top) line of transverse slope, the elevation of the top surface of skeleton foundation should be determined, and the position of skeleton should be accurately set out according to the length of this section of slope. After the line position is determined, it shall be reported to the supervisor for testing, and the next working procedure shall be carried out after it meets the requirements.
2, concrete materials and pouring requirements
The grid skeleton material is C20 concrete, which will be supplied by the mixing station in our contract section. Because concrete needs to be poured on the slope, the slump of concrete is controlled at 3 ~ 5 cm, and the workability is good. Because the skeleton is small in size and located on a slope, artificial steel bars are used for vibrating during pouring. In order to prevent the concrete from sliding down, the method of adding baffles on the partition can be adopted.
3, the construction method
(1) skeleton trench excavation
Due to the operation on the slope, and the width of the skeleton is only 40cm, it is not suitable for mechanical operation, so all trenches are excavated manually. Before manual excavation, determine the position according to survey and layout, and strictly control the excavation width and depth. Overexcavation and underexcavation are not allowed to ensure that the edge of the skeleton is straight and the excavation is carried out from top to bottom. No loose soil can be left in the ditch, and it should be compacted manually. The excavation length is generally determined according to the construction capacity and weather conditions, and the excavated trench shall not be suspended for a long time.
(2) Trench excavation of skeleton foundation
After the opening of the upper skeleton and arch rib groove of a certain section, remove the abandoned soil of this section, and then restore the excavation edge and elevation control points of the footrest foundation pit. Excavators can be used to cooperate with manual excavation. After the excavation is completed, the loose soil at the bottom of the pit shall be removed manually, leveled and compacted by a small vibration dynamic compactor.
(3) Slope protection foundation construction
After the foundation pit excavation is completed, install the formwork according to the design requirements. After the formwork installation is completed, the plane position and elevation of the footguard foundation should be checked again. After confirmation, it shall be reported to the supervision engineer for on-site inspection and acceptance, and concrete for toe protection foundation shall be poured. When vibrating compaction, attention must be paid to manually inserting steel bars.
(4) pouring grid skeleton concrete
After the foundation concrete pouring is completed, the upper grid skeleton concrete can be poured. Transportation by chute or hopper car also requires vibration compaction.
(5) Setting of settlement joint
According to the length of the construction section, expansion joints are set at 10m ~ 18m section. The seam is required to be 2cm wide and filled with asphalt hemp.
(6) Health care
After the completion of each section of construction, after the initial setting of concrete, cover it with geotextile, and water it regularly for maintenance and covering.
Keep in good health for 7 days, and avoid external force collision, vibration or bearing during maintenance.
4, detection
(1) raw material inspection
Before the materials enter the site, samples of gravel, sand and cement shall be taken and submitted to the supervisor and the laboratory. Only after passing the inspection can they enter the scene. After the materials enter the site, they can only be used after passing the on-site inspection by the supervisor.
Concrete is mixed centrally according to the mixture ratio provided by the laboratory and the mixing station, and the performance of concrete is tested as required, and test blocks are made and sent to the laboratory for testing.
(2) Slope protection detection
After the slope protection masonry is completed for a period of time, according to the slope protection detection and evaluation standards, the line position, elevation, flatness and section size are detected and evaluated as required. Do not meet the requirements, and resolutely rework. In short, in the construction process, we must resolutely ensure the quality and constantly improve.