I. Overview of the Project
K46+740~K47+3 10.68 in my contract section is designed as a reinforced earth retaining wall, with 48 1.3m on the left and right sides ... The reinforced retaining wall panel is made of precast concrete, with the strength grade of C30, and the outer side of the panel is made of rectangular trough plates, with the horizontal spacing Sx=0.5mm and the vertical spacing Sy = 0.5m.. The reinforcement belt is designed as follows. Belt thickness ≥2mm, breaking tension ≥7.5KN, allowable tensile stress [σ]= 1 10MPa, and elongation < 2%. The friction coefficient between the filler of the reinforced retaining wall and the reinforced belt is 0.35, and it is filled with crushed stone soil, that is, the mixed crushed stone content is adopted.
Second, clean up the site and treat the basement.
Before construction, all the roots, turf and humus in the subgrade should be dug out. The bottom of foundation groove (pit) of reinforced retaining wall shall be leveled and compacted. Before laying reinforced earth retaining wall, the bearing capacity of foundation soil (rock) at the bottom of foundation should be tested. When the design value can't be reached, the replacement method is adopted, and the C30 concrete construction of foundation can only be carried out after the design value is reached.
Third, building the foundation
(1) According to the Domestic Bidding Document for Highway Engineering (2003 Edition) issued by the Ministry of Communications;
(2) According to Technical Standard for Highway Engineering (JTGB 01-2003) issued by the Ministry of Communications;
(3) According to the Standard for Quality Inspection and Evaluation of Highway Engineering issued by the Ministry of Communications (JTGF 80-2004) 2004;
(4) According to the Technical Specification for Construction of Highway Reinforced Retaining Walls issued by the Ministry of Communications.
Four. Construction date: June 2005 1 ~ 20051October 15.
Verb (abbreviation of verb) staffing
Six, mechanical configuration
Serial number, model, quantity, 1 17T dump truck, 10, 2 daewoo 220 excavators, 3 3T 140 bulldozers, 3 4ZL50 loaders, 3 4P 160B graders, 2 5 Changsha YZ road rollers.
Seven, the construction method
1, basic processing
The foundation pit of reinforced retaining wall is treated with lime gravel soil replacement, and the bearing capacity of the foundation at the bottom of the foundation is tested. After the bearing capacity meets the design requirements, the foundation adopts 50cm cast-in-place C30 concrete, and the wallboard can be built only after the strength meets the design requirements.
2. Panel installation
When installing panels, the foundation shall be leveled with low-strength mortar, the horizontal error of adjacent panels on the same floor shall be controlled within 8mm, the axis deviation shall not exceed 65,438+00 mm every 20 linear meters, and the joint width of panels shall be 65,438+00 mm. A layer of panels shall not be installed on unfilled panels, and hard stones and iron sheets shall not be used as the bottom of masonry to avoid stress concentration and damage to panels. When installing each floor, use hanging ball and hanging line to check. After the installation of each three-layer panel, measure the elevation and axis in time. Adjust the horizontal and vertical errors step by step in time, and do not adjust after the errors are accumulated.
3, steel belt laying
The ribbon passes through the reserved hole on the panel, and then turns back to the other end for alignment. Ribbons are strictly prohibited from winding into knots on the holes. Ribbons are arranged in a fan shape on the compacted and flat filler. They can't overlap, curl or bend, and they can't come into direct contact with hard edges and corners. The direction of reinforcement at corners and bends is basically perpendicular to the wall. Where it is difficult to arrange steel bars along the direction perpendicular to the wall at the joint with the structure, the steel bars that cannot be arranged vertically will gradually tilt. After the tendon is tensioned and positioned, take a small amount of filler from the pull ring to cover the tendon tail and fix it.
4, packaging construction
Gravel soil filler is fully mixed with 30kg gravel per 70kg soil in the borrow yard, then excavated and loaded by excavator, and transported to the construction site of reinforced retaining wall by dump truck. When discharging, the distance between the machine and the panel shall not be less than 1.5m, and the machine shall not run on the reinforced belt without packing and shall not disturb the reinforced belt below. The particle size of the filler shall not be greater than 1/2 of the compacted thickness of the filler, and the maximum particle size shall not be greater than 10cm. The filler shall not freeze or contain sharp gravel, and it is forbidden to mix organic materials and domestic garbage. The filler shall be paved mechanically, and the distance between the paver and the panel shall not be less than. Within the range of 1.5m from the panel, manual paving is adopted. The packing shall be compacted in layers, and the compaction sequence shall start from the middle of the reinforcement belt, gradually roll to the tail of the reinforcement belt, and then roll to the position close to the panel. The distance between the compaction machine and the panel should not be less than1.0m. Within this range, the filler with good water permeability should be selected first, and it should be lightly pressed with a small roller or tamped manually. It is forbidden to use large and medium-sized compaction machinery.
4. Packing compactness
After the filler is paved and leveled, it shall be tamped with a small roller or manually. When rolling, it should be light before heavy. It is forbidden to use sheep hoof mill, and it is not allowed to turn around and brake suddenly on uncompacted packing. Outside the range of 1.0m from the panel, 0-80cm below the bottom of the tank, and the compactness is greater than 95%. Below 80cm, the degree of compaction is more than 90%, and within the range of 1.0 from the panel, the degree of compaction is more than 90% in the whole wall height range, which meets the design requirements.
5. Wall capping and guardrail construction
After the top wallboard is installed, longitudinal unevenness is formed. Leveling with mortar, strictly control the design elevation. After the leveling mortar reaches a certain strength, the cap stone can be poured. In addition, according to the design, a drainage pipe is set every 10m, and the part extending out of the wall is painted with white paint. The guardrail adopts C25 reinforced concrete anti-collision guardrail, and the middle part of the retaining wall panel and guardrail adopts C25 concrete cast-in-place, and its height is determined by the wall height, so as to facilitate the adjustment of longitudinal slope elevation and reduce irregular panels.
Eight, construction quality, safety and civilized construction requirements
1, quality measures:
(1) During the construction, strictly control the particle size and quality of filler, reasonably select construction equipment with good performance, adopt the best combination mode, and standardize the construction method and technology.
(2) Carry out total quality management, implement project decomposition and target management, and set up QC research group for reinforced earth retaining wall construction to guide the construction scientifically.
(3) Strictly implement double inspection of measurement, implement the system of technical disclosure before construction, and establish three major guarantee systems: organization guarantee, work guarantee and system guarantee.
(4) In the construction process, according to the actual situation, constantly adjust, improve, supplement and summarize, improve the construction parameters, collect technical data in time, and guide the construction correctly.
2. Safety measures:
(1) Regularly carry out safety education, speech and inspection system, set up safety supervision post system, and implement safety technical disclosure system.
(2) Seriously implement standardized operation, strictly implement construction discipline and labor discipline, put an end to illegal command and illegal operation, and make safe production based on scientific management, advanced technology and reliable guarantee.
(3) Use various propaganda tools and take various forms to educate employees to establish the concept of safety first and strengthen the safety awareness of all employees.
3, civilized construction:
(1) Create a beautiful environment, set up enough temporary sanitary facilities in the construction site and living quarters, and clean them up every day. Domestic garbage should be piled up centrally, and construction wastewater and domestic sewage should not pollute the environment.
(2) During the construction, indicate the project name, scope, site director, site layout is reasonable, and materials, articles, machines and tools are piled up to meet the requirements. (3) During the construction period, the construction machinery, vehicles and roads should be maintained frequently, and the construction access road should be kept clear of rain and shine, and sprinkled with water to prevent dust.
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