Construction process block diagram of expressway civil engineering sub-projects (including text description)
1. Construction process of tunnel advanced long pipe shed
(1), process block diagram
Figure 3.5.1.1-1 Pipe shed construction construction process block diagram
(2), construction points
(1), pipe shed drilling rig workbench working platform It is 6m long. The front end is lined with a slurry disc and the steel pipe concrete wall is fixed.
(2). Drilling rig installation and pipe shed positioning.
(3) Drilling: Use the pipe shed drilling rig to rotate and hydraulically propel the hole to the designed depth.
(4) Cleaning the hole: After the hole is formed, use high-pressure water to clean the remaining ballast in the hole.
(5). Hole calibration: When measuring, pull out the drill pipe and drill bit, and use an instrument to measure the offset.
(6) Correction of curved holes: Fill the curved part with mortar and wait for it to solidify before drilling again.
(7) Installing steel pipes: Steel pipe connections can be made by cutting small-diameter steel pipes into large-diameter steel pipes and then welding them.
(8). Hole plugging and grouting.
(9). High-pressure grouting: Reinforce the formation through grouting holes in the steel pipe wall.
2. Tunnel advance small duct construction technology (see Figure 3.5.2)
Figure 35.2 Small duct construction technology block diagram
Construction points:
1. Be familiar with the design drawings, understand the geological conditions, prepare drilling and grouting plans, organize and train the construction team, and equip with sufficient construction machinery and tools.
2. Small duct construction:
(1). The front end of the small duct is made into a pointed cone shape, and a ф6 hoop is welded to the tail. 8mm grouting holes are drilled around the pipe arm, and the tail is There is no grouting hole for 1m.
(2). Before drilling, design the measurement and placement hole positions according to the center line and elevation, and control the drilling direction and extrapolation angle.
(3). After drilling is completed, use Feng Shui pressure to clear the hole.
(4). Cement slurry is used for grouting, and the grouting ratio is determined through actual field tests.
(5). The tail of the leading small duct is welded to the steel arch, and the two rows of small ducts maintain an overlap length of more than 1m.
(6) During the grouting process, records must be filled in tube by tube.
3. Tunnel drill and blast construction technology (see Figure 3.5.3)
Figure 3.5.3 Drill and blast construction technology block diagram
Drill and blast construction technology description
Drilling: Type II and III surrounding rocks are drilled with artificial air guns, and Type IV to V surrounding rocks are drilled with a three-arm drilling rig. The depth, angle, and spacing of the blastholes are designed according to the drilling and blasting design. The requirements are determined, and the blast hole accuracy strictly meets the requirements of the construction specifications.
Charging and network connection: Before charging, blow out the rock powder in the hole and proceed in sections from top to bottom. Millisecond detonators, arithmetic detonators, and second detonators are used to detonate, and the detonation is carried out accurately according to the pre-designed number of eyelet segments. Mixing is prohibited to prevent affecting the blasting effect and causing blind shots.
Network connection: Start connecting to the network after all non-essential machines and equipment have been evacuated from the blasting surface. The connection should be as close to the eyelet as possible, and the network outside the hole should be as short as possible. The connection must be neat and convenient. Visually inspect the network. In order to ensure reliable ignition of the millisecond detonator, the minimum length of the detonator detonator must be less than 1.5m. To detonate the entire network, use No. 8 fire detonators with ordinary fuses. When using electricity or detonators to detonate, the operation method should be carried out in accordance with the relevant provisions of the national standard "Explosion Safety Regulations".
After the network connection is completed, carefully check whether the connection is correct, whether the detonating charge roll of each eyelet is included, and whether there is a detonator in each cluster or connection block. When using extension control outside the hole, it should also be checked whether the number of detonator segments at each connection point complies with the design.
Blasting effect inspection: According to the specification requirements, the excavation section after blasting should meet the requirements in the following table.
Blasting Effect Checklist Table 3.5.3-1
Serial Number Requirements Item Requirements Content
1 The allowable over-under excavation amount for Class II arches is an average of 10cm, with a maximum 15cm; side walls, inverted arches and tunnel bottoms average 10cm.
Class III to V arches average 15cm, maximum 25cm; side walls, inverted arches and tunnel bottoms average 10cm
2 blasthole residual rate hard rock ≥80%, medium hard rock ≥ 70%, soft rock ≥50%, the peripheral eye marks should be evenly distributed on the excavation contour line
3. The step-shaped error when the two shots are connected shall not be greater than 15cm
Four , Tunnel hollow grouting anchor construction technology (see Figure 3.5.4)
Figure 3.5.4 Hollow grouting anchor construction technology block diagram
Construction points
1. Mark the anchor position along the arch excavation contour according to the designed position; use an air gun to drill holes. After drilling to the design depth, clear the hole with water or high-pressure air. After inspection, the anchor rod can be installed.
2. The hollow anchor rod is customized by the manufacturer according to the design requirements. Before use, check whether there is any foreign matter blocking the anchor hole, and clean it if there is any. The anchor rod is installed manually. The exposed length of the anchor rod should be kept at 10 to 15cm, and then the orifice cap (stopper) should be installed.
3. Grouting: The slurry is cement slurry. In order to ensure continuous and uninterrupted grouting, before grouting, you should carefully check whether the grouting pump is in good condition and whether the accessories are available; check whether the raw materials for grouting are available and whether the quality is up to standard.
Grouting sequence: Quickly connect the anchor rod, grouting pipe and grouting pump with quick connectors. Start the grouting pump to inject grout until the grout overflows from around the orifice or the pressure gauge reaches the design pressure value. After an anchor is completed, the grouting hose and anchor joints should be quickly removed, cleaned and moved to the next anchor for use. The grout should be prepared strictly according to the mix ratio and used as needed to prevent the grout from condensing in the grouting pipes and pumps. In order to ensure the grouting effect, the grouting pressure must be strictly controlled. The opening of the rubber grout stopper should not be less than 30cm, and the drilling holes other than the grout stopper must be sealed with quick-setting cement mortar immediately after the air is exhausted.
5. Tunnel mortar anchor construction technology (see Figure 3.5.5)
Figure 3.5.5 Mortar anchor construction technology block diagram
6. Tunnel steel Support construction technology (see Figure 3.5.6)
7. Tunnel wet shotcrete construction technology (see Figure 3.5.7)
Figure 3.5.7 Wet shotcrete construction technology block diagram< /p>
Key points of wet shotcrete construction:
1. The cement is 425# ordinary Portland cement, the sand is machine-made sand, and the gravel particle size is controlled at 5-10mm.
Use liquid quick-setting agent. Before formal spraying, conduct actual tests to measure the actual initial and final setting times, make test pieces, and test the strength of the test pieces to select the optimal mix ratio and verify the operating process.
2. Operation points
①. Spray multiple times in layers according to the thickness. The initial spray thickness is 3 to 5cm, seal the rock surface and make the sprayed surface smooth; bury during layered spraying φ6 steel bar head to check whether the spray layer is smooth. If there is any leakage, it should be re-sprayed.
② Before spraying, clean the rock surface with high-pressure water or high-pressure wind. The spray port is about 1m away from the rock surface. Fix the nozzle on the manipulator for operation. The spray should be vertical to the rock surface, from bottom to top. The spiral moves back and forth in the transverse direction, with one circle pressing half a circle.
⑤ After 2 hours of final setting of the shotcrete, it should be sprayed with water for curing, and the curing time is generally not less than 7 days.
8. Tunnel waterproof layer construction technology (see Figure 3.5.8)
Figure 3.5.8 Waterproof layer construction technology block diagram
9. Tunnel lining concrete construction Technology (see Figure 3.5.9)
Figure 3.5.9 Tunnel secondary lining process flow chart
10. Construction technology of tunnel pavement engineering (see Figure 3.5.10)
p>Figure 3.5.10 Pavement construction process block diagram
Construction process description:
1. Pavement cushion construction
2. Concrete surface layer construction
(1) Before the construction of concrete pavement, the materials entering the site should be inspected, and the inspection items and inspection frequency should comply with the relevant test regulations.
(2) Before construction, mechanical equipment, measuring instruments, baselines or templates, and various test instruments must be comprehensively inspected and debugged. There should be an appropriate amount of reserves for wearing parts of major construction machinery.
(3) Before pouring the concrete surface layer, the floating soil and debris on the surface of the base layer should be removed.
(4) The mixing and transportation of concrete should be handled in accordance with the relevant provisions of Chapter 5 and Chapter 6 of the "Technical Specifications for Construction of Highway Cement Concrete Pavement" (JTGF30-2003).
(5). The pavement construction formwork is made of channel steel. The accuracy and size requirements of the formwork should comply with the provisions of Section 7.3.1 of the "Technical Specifications for Highway Cement Concrete Pavement Construction" (JTGF30-2003).
(6) Concrete panel paving uses a concrete paver, and the process flow is constructed in accordance with the order specified in the "Technical Specifications for Construction of Highway Cement Concrete Pavement" (JTGF30-2003).
(7) In order to increase the compactness and early strength of concrete and improve the physical and mechanical properties, the vacuum water absorption process of pavement concrete is adopted.
3. Construction of longitudinal joints, transverse shrinkage joints and expansion joints
(1) Longitudinal joints, transverse contraction joints and expansion joints should be constructed in accordance with the requirements of the drawings and "Construction of Highway Cement Concrete Pavement" "Technical Specifications" (JTGF30-2003).
(2). The joints should be filled in time according to the drawing after the concrete curing period expires. Before filling, the joints must be kept dry and clean to prevent sand and other debris from falling into the joints.
(3). The filler joints should adhere closely to the concrete joint walls, and the filling depth should be twice the joint width. When the depth is greater than 30 to 40mm, porous flexible substrate materials can be filled. In summer, the caulking material should be filled flush with the board surface; in winter, it should be slightly lower than the board surface.
(4) Before opening to traffic, the caulking material should have sufficient time to harden.
4. The curing should be started immediately after the concrete pavement is paved or the soft anti-slip structure is completed. The spray curing agent and covering should be used in accordance with the "Technical Specifications for Construction of Highway Cement Concrete Pavement" (JTGF30-2003) ) The relevant provisions of Section 9.3 shall be implemented.
11. Tunnel curtain grouting construction technology (see Figure 3.5.11-1)
Figure 3.5.11-1 Drilling grouting operation process flow chart
Operation points:
1. Hole opening and orifice pipe installation: Open the hole with light pressure, slow speed, and sufficient water supply. When burying orifice pipes, use dry-hard early-strength mortar to plug and position them in areas without water. For areas where water is gushing from the orifice, use enhanced waterproofing agent and a pipe-fixing mixture prepared with cement to position and fix the pipes. See the figure for details. 3.5.11-2, the orifice pipe can be drilled or grouted after it has been retained in the pressure water for a certain period of time.
Figure 3.5.11-2 Schematic diagram of the orifice pipe
2. The deviation of the hole bottom of the drilled hole should not be greater than 1/40 of the hole depth. During the drilling process, strictly keep drilling records: hole number, footage, development of rock fissures, location of water inflow, water inflow volume and water inrush pressure, etc.
The pre-grouting methods mainly include the step-by-step forward grouting method from the tunnel face inward; the backward grouting method from the inside out; the comprehensive grouting method; the whole hole one-time grouting method; and small-diameter drilling holes. Mouth sealing grouting method, etc. Considering that the curtain grouting section is mainly located in the fault fracture zone, the order of drilling and grouting is first the outer circle and then the inner circle, first close and then far away. The holes in the same circle are constructed at intervals. When the rock formation is easily broken and can cause hole collapse, advance grouting is used. Otherwise, retreat grouting is used. The grouting pipeline connection is shown in the schematic diagram 3.5.11-3 of the grouting system layout. Before grouting, a pressure water test should be carried out, and rock cracks should be flushed as needed before grouting according to specifications.
Figure 3.5.11-3 Schematic layout of the grouting system
The grouting procedure is:
Table 6 Project Productivity and Construction Periodicity Schedule ** Contract Section
Serial number Project unit number Average scale per production unit (- people, various machines - sets) Average productivity per unit (quantity, weekly) Average construction time per production unit (weeks) Production unit Total number (number)
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