() Level I construction technical disclosure

Name of unit project: subgrade engineering pile number: K 3 1+025—K 50+000 Technical disclosure content: subgrade filling disclosure card number:

I. Project objectives

1, quality target

All technical indicators meet the requirements of the industry and the owner, and ensure that the excellent rate of the project reaches 100%. Quality and progress are among the best in the whole line, ensuring that the construction quality reaches excellent standards.

2, the time limit for a project schedule target

Strictly implement the time limit for the signing of the contract, strengthen on-site construction management, and ensure that the remaining construction tasks in this contract period are completed on schedule.

3. Security objectives

Take effective measures during construction to ensure that no safety accidents occur during construction.

(Attached page)

Approver: Date:

Discloser: Date:

Recipient: Date:

Second, the construction team task division

Arrange three construction teams to carry out construction at the same time, with pile numbers of K3 1+025-K37+650, on both sides of the old road; K37+650-K42+650 new line segment; K42+650-K50+000 old road reconstruction fill section. Each construction team should carry out the construction of multiple construction faces step by step and cross, so as to ensure that all subdivisional work can complete the tasks according to the overall construction schedule.

1) The personnel and equipment of each construction team shall meet the construction requirements, formulate measures according to the construction production plan, adjust resources, and give priority to controlling the quality and progress of the project and the allocation of resources such as people, finance, materials and equipment for key projects.

2) Arrange and organize the construction reasonably, eliminate the influencing factors of rainy days, make full use of sunny days, seize the construction period, grasp the progress, and shorten the process control time.

3) Strengthen the maintenance of machinery, improve the intact rate and productivity of machinery, and ensure the smooth progress of construction production.

4) Do a good job of material supply in advance, dredge the material supply channels, and ensure that the material supply will not affect the construction.

5) Strengthen quality control, eliminate the factors that delay the construction period due to quality reasons, carefully construct and produce efficiently, and achieve excellent engineering standards.

Third, the engineering technical requirements

1, engineers and technicians should be familiar with the design drawings carefully, and make clear the technical requirements of each section, such as structural layer relationship, single slope of pavement, superelevation of transition section, construction elevation control, subgrade widening section, etc. Do know fairly well, ensure the correct construction lofting, and guide the construction in time.

2, the original traverse points can't meet the construction requirements, encryption, to ensure that in the whole process of construction, adjacent traverse points can intervisibility. It must be closed with the traverse points of the adjacent construction section, and the traverse points that hinder the construction should be fixed before construction after retest. The fixed pile shall be firm and reliable, and the pile position shall be convenient for erection of instruments, and shall be located outside the scope of the construction section.

3. Before subgrade starts, fully restore the center line and determine the main control points of the route, such as turning points, circular curves and bends.

The starting point and end point of the transition curve that plays a controlling role, as well as the 100-meter pile and piling. Pay attention when restoring the midline.

When the center of the structure is closed with the center line of the adjacent construction section, find out the reasons in time when problems are found and report them to the engineering department for solution.

4, add temporary leveling point error to meet the requirements of construction accuracy. If individual datum points are found to be working.

Cheng, move it out of the scope of influence, and its elevation should be closed with the original leveling point.

5, engineering measuring instruments should be taken care of, to prevent the loss of knock against, such as instrument damage, should be investigated.

Responsibilities of relevant personnel.

6. Before subgrade filling, engineers and technicians should restore boundary piles and middle piles, as well as all edges of each layer.

The elevation of middle and middle piles should be calculated clearly and accurately. It is necessary to define the compaction range and elevation control of 92%, 94% and 95% of each section. Make clear the filling height and construction content of each section. In the process of concrete construction, the elevation and width should be well controlled to avoid problems.

Four, subgrade earthwork construction technology

1, preparation work

According to the requirements of design, specifications and supervision, clean up the site without damaging the land use scope.

Remove trees, shrubs, stones, waste, garbage and weeds that hinder the sight, construction and quality, put the weeds and other things removed in the designated places, and remove the topsoil at least 100 ~ 300mm below the original ground. After cleaning, humus soil shall not be discarded, but should be neatly stacked between the foot of subgrade slope and the highway boundary, or other suitable storage places as green soil. Investigate the location of hidden pipelines and facilities in the line and the underground facilities that need to be embedded in the construction, and make disclosure to the construction personnel. Topsoil should be removed from the excavation section, and soil suitable for planting should be placed on both sides of subgrade. Humus soil used for planting grass in subgrade protection engineering should be treated according to the owner's instructions.

According to the design scheme, the borrow site should be sloped according to 1: 1.75, and drainage should be done at the same time. Original basis

Humic soil should not be discarded, but should be neatly stacked outside the foot of the slope or other suitable storage places.

Re-cultivate the soil field after it is used up. The construction adopts the method of manual and combined operation of bulldozer, loader, dump truck and grader.

Before embankment filling, pre-filling treatment should be carried out after site cleaning. After clearing the site, the rest of the fill areas will be leveled by grader, potholes will be filled, and compacted by heavy roller to meet the standards required by the owner. Only after self-inspection and supervision approval can the first subgrade be filled.

2. Temporary drainage of subgrade

Before construction, temporary drainage should be done within the scope of subgrade, vertical and horizontal drainage ditches should be excavated in wet areas to eliminate stagnant water and cut off or reduce the groundwater level. During construction in rainy season, prevent embankment from accumulating water, appropriately increase the cross slope on the surface of the filling layer, and build a temporary drainage trough at the edge of the shoulder to facilitate drainage, and pay attention to the weather forecast. The subgrade is rolled and shaped in time to prevent the subgrade filler from being washed away by rain bubbles.

3, subgrade filling

The subgrade shall be filled in layers, and the filling elevation shall be controlled according to the parallel lines of the pavement. The filling operation shall be paved in layers and in parallel, and mechanical compaction shall be adopted. The maximum loose laying thickness of each layer shall be determined through experiments, and generally it shall not exceed 30cm for fine-grained soil. In the construction section of K37+650-K42+650, the lower part of subgrade is filled with fly ash and bound soil, and the top 40cm of subgrade seal is 6%-8% lime soil; K42+650-K50+000 construction section, 30cm of the top surface of subgrade seal is 6%-8% lime soil. The thickness of the compacted layer from the earthwork embankment to the last layer on the top surface of the subgrade shall be no less than 10cm, and the width of each layer of filler shall exceed the designed width of the embankment by 20cm on each side, so as to ensure that the edge of the embankment behind the whole subgrade slope has sufficient compactness and shall be leveled after the subgrade is formed. Fillers with different soil qualities should be filled in layers to minimize the number of layers. The total thickness of each layer of filler should be not less than 50 cm.

When the height of embankment fill is less than 80 cm (excluding the thickness of pavement), the surface of soil foundation should be loosened to a depth of 30 cm after in-situ surface cleaning and excavation, and then leveled and compacted. Its compactness should meet the specification requirements.

When the height of embankment fill is more than 80cm, the embankment base should be leveled and rolled before filling, and the compaction degree should not be less than 85%.

When the natural transverse slope or longitudinal slope of the ground is steeper than 1: 5, the original ground should be dug into steps, and the width of the steps should meet the needs of paving and compaction equipment operation, and not less than 1 m. The top of the step is inclined inward by 2%, and then filled.

When the old embankment is widened in the construction section of K3 1+025-K37+650, the steps will be excavated along the left and right slopes of the old embankment. When the height of the old embankment is less than 2m, the old roadside slope will be cut off at one time along the old shoulder to reduce the uneven settlement of the new and old subgrade. Special attention should be paid to strengthening the mechanical rolling of the widened part to ensure the qualified compaction degree, so as to ensure the overall stability of the original subgrade. The connecting structure of subgrade engineering should avoid endangering the safety and stability of the structure during construction. When channels and approach roads are built in the embankment, new embankments should be filled as required.

When filling subgrade with gravel soil, it should be filled and compacted by layers. Before filling the permeable material, the layer should be covered with soil, and the width of the covered soil should ensure that the clear width after leveling meets the design requirements of the construction drawing. After paving, the permeable materials should be compacted together to meet the compaction standard. The paved permeable materials must be rolled in time to prevent moisture evaporation from affecting the compaction effect. Gravel soil filling subgrade shall be constructed according to the compaction machinery type, compaction times, paving thickness and compaction degree determined by compaction test.

4, subgrade mixed with ash

Because the subgrade earthwork is filled with clay from the borrow yard, but the soil source of the borrow yard now has a high water content, according to the requirements of the headquarters, the earthwork is now treated with 100% lime.

The process method of mixing lime into subgrade: buy qualified quicklime and spread it evenly on the over-wet soil. When the excavator digs, the bucket is turned over for many times, and the lime is evenly mixed into the wet soil, and at the same time, it is dug out and piled up for later use, so that the lime can fully improve the performance of the soil and reduce the water content of the soil.

Quantity, pay attention to the detection of lime dosage and control of soil moisture content, in order to meet the construction requirements. When filling subgrade, lime soil will be loaded with loaders and transported to the construction site by dump trucks for paving and rolling.

5. The laboratory should do heavy standard compaction of plain soil and 2%, 4%, 6% and 8% standard compaction of lime soil, at the same time, do a good job in EDTA titration standard curve of lime dosage, and test it according to the situation during specific construction. When testing, the operator should first determine the standard degree of compaction of the testing part, then determine the degree of compaction, and clearly record the construction paragraphs, parts, layers and ash dosage, and truthfully reflect them to the employees in the industry for easy measurement.

6, subgrade elastic soft treatment

When the subgrade is elastic and soft, the elastic and soft parts of the subgrade should be dug up and discarded, and replaced with materials with appropriate water content. After leveling, mechanical rolling should be strengthened to ensure that the compaction standard is reached.

7. Compaction of subgrade

Before compaction, the fill layer should be leveled and made into a 2%-3% cross slope. Compaction of subgrade filler is carried out by 25T vibratory roller and 18-2 1t roller. The rolling speed should be slow at the beginning, and the maximum speed should not exceed 4 km/h. When rolling, the straight line segment should be carried out from both sides to the middle, advancing and retreating longitudinally, and rolled from the roadside to the middle with a roller, and then rolled from the low side to the high side in turn. Compaction follows the principle of light before heavy, until the designed degree of compaction is achieved.

When rolling transverse joints, vibratory rollers generally overlap 0.4-0.5m, three-wheeled rollers generally overlap 1/2 of the width of thick wheels, and rolling longitudinal joints should overlap 2.0-3.0m, so as to ensure no pressure leakage and dead angle, and ensure the uniformity after rolling. Before paving the next layer, the pass rate of compaction degree of the previous layer should reach 100%, and the next procedure can be carried out only after it is approved by the supervision engineer.

8. Quality inspection

After the completion of each layer of fill, the sand filling method is used for test and detection, so that the compactness of subgrade can meet the specified requirements.

9, joint parts processing

When the embankment is constructed in several sections, if it can't be filled at the same time, the filled section should be filled in layers with steps, and the slope is1:1; If it can be filled in at the same time, the overlapping length must be greater than 2 meters. When filling at the junction of two sections of subgrade at the same time, they must be overlapped by layers, and the connection length shall not be less than 2m.

10, subgrade sealing

The top seal of subgrade is 6%-8% lime soil. According to the soil moisture content, reduce the soil moisture content first, and then add enough quicklime or hydrated lime (fully digested). Seal coat construction should ensure the dosage of lime, and the subgrade surface has good flatness, cross slope and compactness to ensure the subgrade deflection is qualified.

During the construction of subgrade top seal coat, the line must be hung up, and the elevation should be controlled layer by layer. When necessary, the elevation and control points should be encrypted to ensure the accuracy of subgrade elevation. Manual and mechanical leveling can be used to ensure that the elevation of subgrade top surface meets the specification requirements.

1 1, subgrade shaping

After the subgrade project is basically completed, check the centerline, elevation, width, slope gradient and drainage structure of the subgrade according to the design requirements, and carry out subgrade shaping after completion. Roadbed renovation adopts mechanical and manual methods, slope shaping should be cut from top to bottom according to the design slope, and soil compensation is not allowed on the slope. After the completion of subgrade engineering, completion survey must be carried out as the basis for completion acceptance.

Verb (abbreviation of verb) Other requirements

1, all construction personnel should strengthen their sense of responsibility and strictly establish quality awareness. The construction captain, technical director, technical personnel and foreman are all quality responsible persons and guarantors, and they are duty-bound.

2. At the same time, we should pay attention to safety production, strengthen safety education, establish and improve safety rules and regulations, set up safety signs and warning signs on site, and set up safety personnel to supervise and manage on site to eliminate all unsafe factors and ensure that no safety accidents occur during construction.

Please do your job well, seize the opportunity in advance and strive to complete the construction and production tasks as soon as possible. Hereby, thank you! !