Turf slope protection construction
The turf slope protection planting part of this project is on the embankment slope. The planting should be carried out at a relatively low temperature, and attention should be paid to watering and maintenance. The work includes trimming slopes, loosening soil and removing impurities, etc.
1． Construction procedures
Slope modification → loose soil and impurity removal → planting and covering → fertilization and maintenance
2. Construction method
(1) Slope modification: After the embankment slope modification and backfilling is completed, manual slope modification should be carried out to achieve the designed slope. The interior of the frame beams should be leveled and concrete waste and other debris should be cleared away.
(2) Loose soil and remove impurities: After the slope is trimmed, manually loosen the soil layer on the slope surface and spread cultivated soil. The thickness of the loose soil shall not be greater than 30cm. During the loosening process, weeds in the soil layer should also be removed and large pieces of soil broken up.
(3) Sow seeds and cover
1) Grass seed selection: Each grass slope protection is fast in production, drought-resistant, high-temperature resistant, flood-resistant, barren-resistant, acid-resistant, and alkali-resistant It is a grass species that can survive the winter safely. At the same time, slope protection lawns are required to have well-developed, strong, densely intersecting root systems and good coverage. Specific grass species should be purchased according to the instructions of the design or supervision engineer.
2) Seeding method: If there are no clear requirements in the design, two methods of spreading grass seeds or paving turf can be considered to complete the construction of turf slope protection projects. The manual spreading method is to mix the grass seeds evenly in a certain proportion before sowing, and then spread the seeds in a row along the dam slope laterally. A sowing section of 50m is used, and the distance between each row of people is 1 meter. The national patented technology "Law Cultivation Bed" and the designed grass density are strictly followed during seeding.
3) Grass seed covering. After each sowing section is completed, please ask the supervision engineer for approval, promptly cover the slope surface with half a garden handle, and then use manual tapping to stabilize the grass seed and prevent it from spreading. drain.
(4) Fertilization and maintenance
After the grass planting is completed, fertilization and maintenance should be carried out within the specified time to ensure that the emergence and survival rate of the seedlings in the year are above 80%.
(5) When sowing at low temperatures in winter, add spicy food and use plastic film to keep the seeds warm and promote seedlings to prevent frostbite on the seedlings.
(6) Grass block transplanting and laying method
1) The grass source for laying turf should grow well, have high density, and have a sufficient area of ??grass.
2) Cut the grass into squares of 30cm×30cm and 2-3cm thick.
3) The grass blocks can be laid densely or intermittently. The dense paving should be connected to each other without leaving gaps. It is required to quickly form a lawn. The grass blocks should be paved in intervals. The gaps between each grass block should not exceed 4- 6cm. When the grass gap is 4cm wide, the grass blocks must account for more than 70% of the total lawn. The gaps should be backfilled with grass. After the grass blocks are laid, they should be compacted and watered.
3. Quality requirements for turf slope protection
(1) The full coverage rate of sown turf should reach 90%.
(2) The densely laid turf is not dead, grows normally, and the coverage rate reaches 95.
Sild excavation
(1), pumping and measuring after pumping, the elevation of the silt surface can be measured by the section method or the grid method. When the water cannot be completely removed, a larger deep pit is dug in a corner; a large pump continuously pumps water to keep the water level lower than the silt surface.
(2) Fill the sidewalk with soil extending from one or more sides of the pit into the pit (squeeze filling method, pile up straight, and use a bulldozer to compact it repeatedly to facilitate driving)
(3) The excavator is placed in the access road to dig out the silt on both sides, and the vehicles are transported out through the access road. When the progress is fast, multiple access roads can be set up so as not to interfere with each other and to excavate effectively.
(4) In some areas, close to the edge of the pit, two or three excavators can be used to transfer to the pit in stages and transport them away.
(5) During the silt excavation process, the best phenomenon is that the water has been drained and there is no intermittent seepage. If there is seepage, the pumping plan needs to be continuously adjusted.
If there is no groundwater seepage, it is best to use an excavator to straighten the bottom surface of the pit; if there is groundwater seepage, increase the pumping intensity after the excavation is completed, and use an excavator or bulldozer (if it can walk) to smooth the bottom surface;
(6) To measure the elevation of the pit bottom, use the same measurement method as the top surface, corresponding to the cross section or grid intersection.
(7) Increase pumping intensity and quickly complete operations such as laying geotextile. You can use the push method to lay one section and fill another section.
Construction technology of stone-embedded concrete project
Construction sequence: construction preparation → measurement and setting out → base surface cleaning → formwork installation → stone-embedded concrete pouring → expansion joint treatment → concrete form removal and maintenance.
1) Construction preparations
Set water retaining cofferdams on the river side, excavate surrounding drainage ditches, and take measures such as pumping water from sump pits to prevent off-site water flow from entering the site and effectively Remove standing water.
2) Measuring and setting out
Measuring and setting out must be carried out with theodolite, level and steel ruler, and setting out stakes should be set according to the spacing between concrete expansion joints. Surveyors must have corresponding professional knowledge and corresponding work experience, and must hold certificates to work. During the construction process, protective facilities should be set up for the measurement datum points, datum lines and level points to avoid damage.
3) Base surface cleaning
After the base surface is accepted, remove debris, soil and loose rocks from the rock base, and then pour concrete after the treatment is completed.
For bedrock surface pouring warehouses, before pouring the first layer of concrete, a layer of 2-3cm thick cement mortar must be laid. The water-cement ratio of the mortar should be compatible with the pouring strength of the concrete. The laying construction process Ensure that the concrete is well bonded with the bedrock.
4) Template making and installation
Template making: Standard wooden boards are used for splicing, and the local curved surfaces are processed and made with wooden boards according to the planar expansion.
Formwork installation: Before installing the formwork, measure and set out according to the design dimensions of the structure's appearance, and set up control points in multiple directions for correction. When erecting the formwork, nail the formwork to the wooden supports, and then support the wooden supports to a solid ground.
5) Concrete pouring
The main construction technology of concrete pouring: mixing → transportation → vibration → curing.
Commercial concrete is used for concrete
Concrete and stone are transported horizontally to the working warehouse using double rubber-tired trucks. It is strictly prohibited to pour concrete directly from high places. The vertical distance between the entrance and the warehouse surface should be controlled within 1.5m. If the vertical distance is too large, a chute or chute must be installed as a buffer.
The stone-buried concrete rate shall be 25% and the stone-buried concrete thickness shall be 500% as required by the design. During construction, a layer of concrete should be laid first, followed by a layer of stones, and then vibrated and compacted until the stones sink into the concrete. Do not place stones first and then pour concrete.
The size of the stones used for burying the stones shall not be larger than 1/3 of the minimum size of the concrete block poured at one time. It is required that the texture is hard and fresh, without weathering or cracks, the saturated compressive strength is greater than 300kg/cm2, and it must be clean.
When pouring, first lay a layer of concrete base with a thickness of 100~150mm, and then lay the stones. The stones should be laid evenly so that the big end is downward and the small end is upward, and the texture of the stone is perpendicular to the direction of stress. The distance between stones is generally not less than 100mm, and the distance between stones and formwork or groove walls should not be less than 150mm to ensure that each stone is wrapped in concrete.
After the stones are laid, continue pouring concrete. Each layer is about 200~250mm thick. Use a vibrator to vibrate. Avoid contact with the formwork and stones during vibration. Pave stones and pour concrete layer by layer in this way until the final level, maintaining a concrete covering layer of no less than 100mm thick on the top surface of the stones, and the quantity of stones used is 15 of the base volume.
The placement of the vibrator into the plane and the vibration time must meet the requirements of the specification to ensure sufficient vibration.
When pouring stone-embedded concrete, the joints should be cleaned. When pouring, the construction joints should be cleaned, and a layer of cement mortar that is exactly the same as the concrete should be laid, and then continue pouring concrete and laying stones.
6) Expansion joint treatment
Expansion joint construction is carried out after the concrete construction is completed. During concrete construction, asphalt wood boards are first installed at the joints according to the designed thickness together with the formwork. .
7) Concrete form removal and curing
Start watering and curing within 12 to 18 hours after the concrete is closed, keep the concrete surface moist, and cover it with straw curtains to keep it moist. Under normal temperatures The covering can be removed after 7 days of curing.
The time limit for the removal of concrete formwork must comply with the provisions of the construction drawings. The non-load-bearing side formwork can only be removed when the concrete strength reaches the point where the surface and edges will not be lost due to formwork removal. The load-bearing formwork can only be removed when the concrete strength reaches the design value. Removable.
8.6 Construction of mortar chip (block) stone
The foundation pit shall be excavated by skipping and constructed in sections. After excavation, the mortar chip stone foundation shall be constructed promptly. In the slurry method, the lower layer is not vibrated when laying the upper layer, and the surface of the lower layer is cleaned and moistened before laying. There should be no through joints or excessively large triangular gaps during masonry, and the mortar must be full. The non-rock foundation shall be 10 to 15 m, and the rock foundation shall not be larger than 25 m to set settlement joints. The seam width is 2~3cm.
1. The construction process is shown in the figure below
Construction process flow chart of mortar rubble retaining wall
2. Construction plan and method
(1). Ground drainage must be done before construction. In soft strata or sloped layer areas, the entire foundation pit must not be excavated to avoid soil collapse before the retaining wall is completed. Jump excavation must be used. Construction shall be carried out in timely and segmented masonry method.
(2) After excavation of the foundation pit, if it is found that the bearing capacity of the foundation is different from the design requirements, report it to the design unit based on the actual conditions and adjust the design in a timely manner.
(3). The masonry stones must be carefully selected, with hard texture, uniform color, no cracks, no rust, and not easily weathered. The compressive strength of the stone should not be less than 30Mpa. There should be no through joints or excessively large triangular gaps during masonry, and the mortar must be full.
(4) When masonry, hang wires on both sides of the poles or templates. The outer lines should be straight and neat, and the slope should be tapered layer by layer. The inner lines should be generally smooth. During the masonry process, the wire rods are often corrected to ensure that the dimensions of each part of the masonry meet the design requirements.
(5). The masonry adopts the grouting method. When building the upper layer, the lower layer should not be vibrated. The surface of the lower layer should be cleaned and moistened before masonry. Methods such as "Ding", "Shun", "Inlaid" and "Wedge" are used to make the stones densely embedded and the wall stable.
(6) The bottom, top and outer layer of the wall should be built with relatively neat large stones, with the same floor height.
(7) Before constructing the retaining wall, the slope surface must be dense and flat before masonry can be carried out. Ensure that the retaining wall facilities can be closely integrated with the earth and rock slopes, and no gaps are allowed.
(8). Use larger and flat stones or blocks for the exposed surfaces, slope tops, and edges of the masonry, and trim them slightly. The stones in other parts should have uniform appearance, color, and texture. It is hard and not easily weathered. The stones should be watered and moistened before masonry, and the surface soil and rust must be cleaned away. The vertical joints of each working layer should be staggered from each other and must not penetrate each other. The width of the vertical joints should not be greater than 3cm. The joints are made using the flat groove method (recessed joints), and after the mortar is initially set, water is sprinkled for curing.