Construction scheme of hospital foundation and foundation engineering
1 project introduction
The basement of this project is mainly distributed under the outpatient medical technology building, dormitory buildings A, B, C, administrative office building, fever clinic and emergency center. Basement 1, the construction area of the underground part is about 13075.52 square meters, and the elevation of the basement is-3.90 m. According to the geological report, the soil condition of the project site is good, and the groundwater level is 0.7 m ~ 2.7 m below the ground in rainy season, and it drops about 0.5~ 1.5m in dry season.
The foundation structure without basement is an independent foundation with pile caps.
The foundation and foundation subdivisional works of this project mainly include subdivisions and subdivisional works such as earthwork drainage, slope protection, pile foundation, underground waterproofing and reinforced concrete structure below 0.00.
2 Construction sequence
2. 1 Foundation engineering construction is divided into four areas to be carried out at the same time.
2.2 Foundation and foundation engineering construction sequence
Earthwork excavation by layers, slope support → pile foundation construction → earthwork excavation of pile cap, ground beam foundation groove, cushion and brick tire mold → pile cap, ground beam and floor structure → basement structure → external wall waterproofing → backfill soil (only after the first template is removed).
3 foundation pit support design
Hospital B is located at the intersection of Yuanshan North Road in the southwest section of Huancheng Road in Town B, adjacent to Hexi Industrial Park, at the junction of the town center and the outer edge. There are no houses, factories, schools and convenient transportation around. The total planned land area of the hospital is 10 1223.60 square meters, which is about 15 1.83 mu. The first-phase construction area is 104758.33 m2, with 4~ 12 floors above ground and 1 floor underground. The design is 0.00, and the corresponding elevation is 15m.
The engineering site is uneven, the natural ground elevation is 9.90m~ 10m, the average elevation is about 13.34m, and the buried depth of foundation is about 3.85m The engineering site has good geological conditions and the surrounding area is relatively empty. What kind of supporting scheme can achieve the purpose of rapid construction and low cost is the most concerned issue of Party A. In view of the above problems, the analysis and calculation of foundation pit support scheme are as follows.
3. 1 Overview of engineering geology and hydrogeology
1, geological conditions
According to the Geotechnical Engineering Investigation Report of Big Hospital provided by Shaoguan Geological Engineering Investigation Institute (July 2006), the soil layer of the proposed site is as follows from top to bottom:
(1) topsoil
Grayish yellow, mainly clayey soil, mixed with plant humus, containing more sand and being soft locally. The layer thickness is 0.40 ~1.10m;
(2) Quaternary alluvium
(1) Clay layer: yellow and yellow-red, mainly clay particles, plastic, smooth section, strong viscosity, medium dry strength and toughness, and layer thickness1.00 ~ 7.00 m;
(2) Muddy soil layer: gray, mainly clay and sandy, soft and plastic, smooth section, strong viscosity, moderate deviation of dry strength and toughness, and 0.50 ~ 2.50 m thick;
(3) Sandy silty clay layer: grayish white, mainly clay, sandy, plastic, partially hard plastic, rough section, medium dry strength and toughness, and layer thickness1.50 ~ 5.00 m;
(4) Medium sand layer: yellow, mainly quartz sand, saturated, slightly to moderately dense, with good sorting property and layer thickness of1.00 ~ 3.00 m;
(3) Weathered residual granite sandy cohesive soil layer
Locally plastic, with a layer thickness of 4.50 ~ 25.00 meters;
④ Yanshanian intrusive granite
(1) Fully weathered granite: maroon, taupe, hard, retaining original rock structure, with fine feldspar grains, and the core is in the form of soil column with a layer thickness of 4.00~ 12.00m, and the core is in the form of hard soil;
(2) Strongly weathered granite: yellowish brown, grayish white, grayish brown, hemp yellow, brown, with developed cracks, unexposed broken core, and layer thickness of 2.10 ~ 6.80m ~ 6.80m. ..
2. Hydrological situation
All soil layers in the site are strongly permeable except sand layers (2-4 layers), and the rest are weakly permeable. There is also a certain amount of groundwater in the cracks of weathered bedrock layer and plain fill layer. The hydraulic connection between soil layers is obvious. The main recharge sources of groundwater in the site are lateral aquifer overflow recharge and atmospheric precipitation recharge. The water level changes with the seasonal climate, and the buried depth is 0.7 ~ 2.70m in wet season and 0.5 ~1.5m in dry season.
Selection of Foundation Pit Support Scheme in 6.2.3.2
There are several economic schemes for temporary foundation pit support: 1, steel sheet pile scheme; 2, spray anchor net support scheme; 3. Slope placement scheme.
Because the geological conditions of this project are good, the soil quality is mainly residual soil, and the surrounding area of the project site is relatively empty, according to our previous experience in similar projects, it is the most economical scheme to adopt the large slope placement scheme in this project.
According to the geotechnical investigation report, the site is mainly residual soil, and its mechanical parameters are γ= 19kN/m3, c=38.5kPa, φ = 2 1.3. Because the depth of foundation pit base is about 3.85 meters, the buried depth of pile caps is different. For pile caps, different slope ratios are adopted according to specific conditions. Because there is no building in the basement, 1: 1 is adopted.
The slope of foundation pit adopts 50-thick shotcrete, with 50×50 steel wire mesh inside, and the steel bar head is fixed, with a fixed point per square meter.
3.3 Calculation results
According to the actual situation of this project, the slope is temporary. The adopted slope ratio is 1: 1, and the analysis and calculation are as follows. Considering the overload of 20kPa at the top of the slope, a drainage ditch is set at the top of the slope, and C20 concrete with a thickness of 50mm is sprayed on the slope for slope protection. The calculation results of each part are as follows.
3) 1: 1 slope with a height of 3.85m
As can be seen from the above calculation results, the slope stability coefficient Ks=2.92, which meets the requirements of the code and the slope is safe.
3.4 Conclusion
1. It is feasible and economical to adopt graded slope excavation scheme for this foundation pit.
2, in the process of earthwork excavation, in strict accordance with the design slope, it is forbidden to overbreak.
3, in the process of construction, pay attention to observe the slope displacement, solve the problem in time, to ensure the safety of foundation pit.
4 Foundation pit drainage and construction methods
4. 1 foundation pit dewatering
At the same time of pile foundation engineering construction, dewatering well construction and drainage are carried out.
Set 300×300mm intercepting ditch around the top of the slope, set 400×300mm drainage ditch along the wall at the bottom of the pit, with the spacing of 15m or set 800×800× 1000mm sump at the corner. The foundation bearing platform is dehydrated separately, and the water of the bearing platform is pumped to the drainage ditch and then to the ground. See the schematic diagram of foundation pit excavation for details.
5 Pile foundation engineering
5. 1 Overview of pile foundation
This project mainly adopts the independent foundation of pile caps. The pile is 400 high-strength prestressed pipe pile (type A), and the bearing layer at the pile end is strongly weathered granite, and the penetration depth is not less than1m. Piles are divided into bearing piles and uplift piles, and a small amount of deep mixing piles are also used in laundry rooms and morgues.
5.2 Preparation for Pile Foundation Construction
1) material preparation
Due to the tight construction period, materials must be prepared, and there can be no material shutdown. Therefore, pipe piles, pile tips, covered electrode, etc. It must be prepared for 3 days.
2) Mechanical preparation
According to the actual situation, in order to meet the requirements of the construction period, the total * * * is equipped with 7 diesel pile drivers.
3) Site preparation
Clean up the debris on the surface of the site, put away the control points, lay the gantry piles and protect the control points. Construction power lines are erected to the site, and construction water pipelines are installed to the construction site.
4) Technical preparation
Be familiar with the drawings, do indoor calculation according to the construction drawing and the anchor points and elevation points provided by the owner, set out the positions of piles according to the calculation structure, mark them, and make technical disclosure to ZuoYeDui.
5.3 Walking route of pile driver
Hammer piles are used in this project, which is restricted by the progress of earthwork excavation in the basement subcontracted by the owner. Pile foundation construction is divided into two areas, namely, the above-ground part and the underground part. First, carry out the pile foundation construction of the ground outpatient medical technology building, and then carry out the basement construction of the staff dormitory and inpatient building after the construction is completed.
The walking route of the pile driver is as follows:
Figure 5.3 The walking route of the pile driver is as follows
5.4 Construction Technology
1, hammering pile construction
1) flow chart (as shown in figure 5.4- 1)
Figure 5.4- 1 piling hammer process
2) Construction technology
(1) Adjust the pile driver in place, so that the pile frame (or tappet) is in a vertical state, and set a scale on the side to be driven or on the pile frame.
(2) According to the length of the pile, lift the lower section of the pile with a suitable lifting point and align it vertically with the center of the pile. Slowly loosen the pile cap (padding) under the pile hammer to cover the pile top, remove the hook, and check that the pile hammer, pile cap and pile are on the same axis and vertically inserted into the soil.
(3) Gently lift the hammer or hammer, and under the inspection of two theodolite, keep the pile vertical, then the pile can be sunk formally.
(4) When the current pile top is 50cm away from the surface, it can be stopped, and the upper pile can also be lifted, and then it can be connected after being aligned with the lower pile.
(5) Welding is carried out in three layers, and the internal welding slag must be cleaned and the weld seam is full. After welding pile extension is completed, it can be cooled for 8min under natural conditions, and then continue to sink on the pile.
(6) When the top of the upper pile is 50cm away from the surface, choose a suitable pile driver to deliver the pile, and make the center line of the pile driver coincide with the center line of the pile body. After sending the pile to the design elevation, pull out the pile feeder.
(7) The pile driver shifts to the next pile position.
2. Deep mixing pile construction
1) process
The main construction procedures of mixing pile include hole location lofting, positioning and centering, ready-mixed sinking, preparation of curing agent slurry, shotcreting and stirring to lift the pile, and repeated stirring. The process flow is shown in Figure 8-7:
Construction Technology of Mixing Pile Tu Tu 8-7
2) Construction technology
(1) The mixing device is in place, pre-mixed and sunk.
Before the pile driver is in place, clean up the bricks, stones and other hard objects in the pile position, move the mixing rig to the construction pile position, adjust the mixer and the mixer guide frame, and aim the mixing head at the center of the pile. The deviation of pile position is less than 50mm, and the verticality deviation is less than 65438 0.0%. Check the equipment and piping system before mixing, and the pressure and flow must meet the design requirements. Grouting pipe and nozzle can not have sundry, grouting pipe joint sealing ring must be good.
After the drilling rig is in place, start the generator of the mixer. When the rotating speed of the mixing head is normal, loosen the chain hoist to make the mixer sink and stir along the guide frame. With the increase of sinking depth, or when encountering hard soil, the soil can be repeatedly dug up and down to make the mixing head sink smoothly to ensure the verticality of the pile.
The technical parameters of the mixing pile are as follows:
Forward and reverse rotation speed of main engine turntable: 28-93r/min.
Hoisting speed of main engine: 0.47-1.47m/min.
Pile-forming speed of sprayed concrete: 0.47-0.90m/min.
Slurry pump delivery: 0.58-7.70 m3/h.
Working pressure of mud pump:1.5mpa.
Outlet pressure of liquid slurry: 0.4-0.6MPa.
(2) Preparation of curing agent
The curing agent of the mixing pile is cement slurry, the cement is 425# ordinary portland cement and the water is tap water. The water-cement ratio of cement slurry is 0.6: 1-0.75: 1, with the maximum not exceeding 1: 1, which can be adjusted according to the actual water content of the formation. When the water content is high, the water-cement ratio is slightly smaller. When the water content is high, the water-cement ratio is slightly higher. For the soil layer with high water content, 3-5% lignin carbonate or 2-3% calcium chloride and other early strength agents can be mixed into the cement slurry to play the role of rapid setting and early strength.
The mixing ratio of curing agent (cement) is 10%- 15%, that is, 38-57 kg of cement is added per meter of pile.
The preparation of curing agent begins with the mixer in place, and it is prepared while stirring, and it is kept stirring to prevent the cement slurry from separating.
(3) shotcreting, stirring and lifting to form piles
After the mixer is transferred from the top of the pile to the bottom of the designed pile, start the mortar pump. When the slurry reaches the nozzle, it will be sprayed at the same time to increase the speed, so that the slurry and soil can be fully mixed until it falls to the ground.
In the process of gunite mixing, if there is a fault, the pile-forming process will be interrupted. In order to prevent pile breakage, after the mixer is restarted, the mixing part should be overlapped by 50cm.
(4) repeatedly stirring
When the concrete sprayed by the deep mixer is lifted to the designed top elevation, turn off the mortar pump, and the mixer will sink and lift, and stir again within 6m of the pile top (reinforcement section). At this point, the slurry in the hopper should be just emptied. In order to mix the soft soil and mud evenly, the deep mixer sinks again, and after reaching the design depth, the mixer is hoisted out of the ground.
6 infrastructure project
In the process of infrastructure construction, crack prevention and seepage control is an important link in construction. Therefore, in the construction, we should focus on controlling the external wall formwork and the pouring of impervious concrete for the external wall and bottom plate. Therefore, the construction joints should be properly handled during the infrastructure construction to ensure that there are no quality defects such as cracks and leakage.
7. 1 construction sequence
Pile cutting and residual soil cleaning and transportation → measuring and setting out → cushion template of pile cap beam → bottom cushion → waterproof layer → bottom plate reinforcement binding and wall column reinforcement insertion → bottom plate side template → concrete pouring → wall column reinforcement binding → wall column concrete pouring → first floor beam slab template → first floor beam slab reinforcement binding → first floor beam slab concrete pouring → external wall waterproof layer → protective layer → foundation pit backfilling.
7.2 template engineering
(1) The ground beam is built with brick tire mold, the inside is plastered with cement mortar, and the outside is tamped with artificial backfill soil.
(2) The bearing platform is supported by nine splints.
(3) Foundation slab formwork
The foundation slab is 400 mm thick. After the waterproof and concrete cushion construction is completed, the external formwork of the bottom plate shall be built with a brick formwork with a thickness of 240 mm and a height of 650mm, and a brick pier shall be set every 3 m. The brick pier shall be built with mixed mortar, and the internal wall shall be leveled with mixed mortar. When pouring floor concrete, the wall construction joints should be left 500mm above the floor, and hanging formwork should be set at this position. The plastic-coated bamboo plywood side formwork is supported on the 16 reinforced horse stool, and the steel pipe is supported and fixed. See the schematic diagram of bottom formwork for details.
(3) the basement wall template
The wall formwork shall be made of 15 thick high-strength plastic-coated bamboo veneer, with 50× 100 wooden keel as back hoop, with a spacing of ≯400mm, and shall be made according to the wall plane. high
Use 2 "long wood screws to connect the strong plastic-coated bamboo veneer wood belt, drill φ4mm holes in the bamboo veneer, and screw them on the wood belt with wood screws. Wood square must be straight, and the section of wood joint exceeding 1/3 cannot be used. M 12 bolt is used for plate-to-plate splicing, and the length is 130. The main keel adopts φ48@500 double steel pipes and is fixed with Ф12 @ 600× 500 opposite bolts. See the template drawings for details.
Wall formwork design and assembly drawing
(4) the basement column template with the main structure at the back of the chapter "template engineering".
(5) template of post-cast strip
Considering the external water pressure and soil pressure of the post-pouring belt, a 240-thick brick wall is built outside the post-pouring belt of concrete wallboard, and the brick wall is built with M5 cement mortar, and the mixed mortar is used for external use to smooth and polish, and the dried concrete wall is waterproof at the same time. Make a protective layer outside the waterproof layer, and then backfill. The formwork on both sides of post-cast strip is replaced by easy-closing net. Support adopts steel mesh and steel support.
Considering the groundwater pressure, reinforcement measures should be taken for the cushion concrete at the lower part of post-cast strip, with the local depth of 100 and the thickness of reinforced concrete of 100 to prevent water pressure from damaging the cushion of post-cast strip.
7.3 reinforcement engineering
(1) The construction method of reinforcement engineering is the same as that of reinforcement engineering of main structure.
(2) In the parts that cannot be covered by the tower crane, the processed steel bars are hoisted into the foundation pit by the truck crane.
7.4 concrete works
The concrete construction of basement floor and wall column beam slab is the same as that of the main structure concrete project. This paper mainly introduces the temperature control and preventive measures of mass concrete in basement floor, wall column and beam slab.
(1) Selection of concrete raw materials: In order to ensure the construction quality of concrete, the selection of raw materials is extremely important, and the materials entering the site must be strictly selected and meet the requirements of various specifications before they can be used.
① Cement: 425# slag cement is selected and mixed with fly ash. According to the characteristics of mass concrete, the strength grade of concrete is C40. In order to reduce the hydration heat of cement as much as possible, under the condition of meeting the quality requirements of concrete, fly ash is properly mixed, because the dosage of cement can be reduced, and the hydration heat of fly ash is lower than that of ordinary portland cement, which can delay the arrival of the peak of hydration heat, benefit the strength growth of concrete and avoid cracks caused by excessive temperature stress.
Cement, fly ash approach must be strictly accepted, there must be a factory certificate or test certificate. Cement should be sampled and tested according to the acceptance regulations, especially the stability of cement, which must be strictly tested.
② Stone: Granite macadam with good gradation is selected, with a particle size of 10 ~ 30mm, a silt content of no more than 1% and no organic impurities.
③ Sand: medium and coarse sand with good gradation shall be selected, and the silt content shall not exceed 2%, and the sand passing through the 0.3 15mm sieve shall not be less than 15%.
④ Admixture: CEA expansive agent is selected.
⑤ Concrete mix design: Through the experimental study of various mix ratios in the laboratory, the best mix ratio is selected as the construction mix ratio for producing concrete, which meets the following requirements: the concrete strength is not lower than C25. The water-cement ratio shall be controlled within 0.4, and the slump shall be controlled within 14- 17cm. The initial setting time of concrete shall not be less than 6 hours. The sand ratio of concrete is controlled at 35% ~ 40%. Additives can reduce the peak heat of cement hydration and delay the time of peak heat; Delaying concrete setting time, reducing cement consumption, reducing hydration heat, reducing concrete drying shrinkage, improving concrete strength and improving concrete workability.
(2) Technical measures to reduce hydration heat and concrete temperature.
(1) Fly ash is added to concrete ingredients to reduce cement consumption and hydration heat. By adding a large amount of fly ash, we strive to reduce the cement consumption 15-20%, which is the most effective safety guarantee to reduce the hydration heat, increase the temperature and make the floor construction smooth.
(2) The use of superplasticizer in concrete batching. Coupled with the use of fly ash, the cement consumption per M3 of concrete can be controlled within the minimum value.
(3) Reduce the temperature of concrete entering the mold: the raw materials of ready-mixed concrete should be cooled before mixing, and the skin of the tank car should be sprayed with cold water to cool down when entering the site, so that the temperature of concrete entering the mold is not higher than the atmospheric temperature.
(4) Strengthen concrete vibrating to improve concrete compactness;
(3) Temperature measurement and temperature control after concrete pouring
(1) Selection of temperature measurement method: In order to grasp the temperature change caused by hydration heat of cement slurry in the hardening process of concrete in time, prevent cracks caused by excessive internal and external temperature difference during concrete pouring and curing, and take effective measures at any time to control the internal and external temperature difference of concrete within the allowable range (25℃) to ensure the construction quality of concrete, glass mercury thermometer is used to monitor the bottom concrete.
② Arrangement of temperature measuring points of glass mercury thermometer
In order to make the arrangement of temperature measuring points representative and fully reflect the temperature change inside the concrete, the temperature measuring points are arranged at the bottom, middle and bearing surface of the concrete pouring height section of the bottom plate, as well as the middle of the plane size. The temperature measuring point at the bottom of the bottom plate should be arranged at the height of 150mm from the bottom surface, and the temperature measuring point of the glass mercury thermometer should be set in each column cap.
③ Reservation of temperature measuring hole of glass mercury thermometer
The thermometer hole of glass mercury thermometer is embedded in φ20mm thin-walled galvanized iron pipe with different depths. The iron plate is welded at the bottom of the steel pipe first, and the upper part is plugged with a cork to prevent cement mortar and water from being immersed. Iron pipes can be welded to the steel skeleton.
④ Temperature monitoring
Temperature measurement must be carried out in numerical order, and the measurement data should be recorded in a table prepared in advance. The temperature measuring time of concrete shall be measured 12 hours after concrete pouring, and then every 2 ~ 4 hours. Check at any time during the test and measure the atmospheric temperature at the same time. Before measuring the temperature, insert the glass thermometer into the embedded iron pipe and plug the top of the steel pipe with a cork, so that the thermometer stays in the pipe for not less than 5 minutes. When the thermometer is pulled out of the tube, the finger is quickly stuck at the scale showing the temperature, and the temperature value is read out immediately. Monitoring should be strengthened within 3 ~ 5 days, and the monitoring time should be within 20℃ between the concrete surface temperature and the ambient temperature, and between the concrete center temperature and the surface temperature.
(4) Calculation and countermeasures of crack control after concrete pouring.
① Calculation of crack control after pouring: After pouring, calculate the temperature shrinkage and tensile stress of concrete in each cooling stage according to the measured temperature value and the controlled temperature rise and fall curve, and take effective measures to strengthen maintenance, slow down the cooling speed, improve the tensile strength of concrete and ensure the quality.
② Temperature control index: the difference between the center temperature and the surface temperature is ≤25℃, and the cooling rate is ≤2℃/24h.
(3) when the temperature difference between inside and outside is close to 25 degrees or the cooling speed is too fast, adjust the covering thickness in time. After the temperature difference between concrete and atmosphere is stabilized within 25 degrees, the covering layer is removed and naturally cured. The curing time shall not be less than 14 days.
7.5 Construction joint and post-cast strip treatment
(1) Design of floor construction joints
Floor construction joints should be set according to the design position. When the design is not clear, press 35m.
(2) Design of construction joints of underground external walls
The external wall of the basement with vertical construction joints is designed according to the design position, which is the same as the position of the bottom post-pouring belt.
According to previous construction experience, if the length of the primary wall is too long, cracks will inevitably appear at the bottom of the temperature. In order to prevent or reduce the occurrence of temperature stress cracks, a vertical post-pouring belt is set every 20m-25m according to the requirements of the specification.
(3) Construction joint treatment method
(1) The horizontal joint of the secondary pouring interface between the concrete bottom plate and the side wall plate shall be made of water-stop steel plates with a thickness of 2mm and a width of 300mm, which shall be evenly and vertically placed around the upper part of the bottom plate, and slotted outwards, and the upper and lower joints shall be inlaid with a width of 150mm.
(2) The horizontal joint formed by the bottom plate is made of BW-2 water-swellable waterstop with specifications of 20×30mm, which is placed in the reserved construction joint and fixed before the secondary concrete pouring; The vertical joints formed on both sides of post-cast strip are also treated with embedded expansion water stop; Cleaning, chiseling, painting, caulking, secondary pouring and other processes must be carried out to ensure the construction quality of concrete at the joints, so as to achieve the purpose of waterproofing.
(3) The settlement joint (vertical joint) in each construction area adopts the method of embedding rubber water stop between two bottom plates. Rubber waterstops with a width of 300mm and a thickness of 20mm are placed horizontally in their respective floors, with a width of 150mm, perpendicular to the construction joints, so as to adapt to the settlement difference and prevent groundwater leakage.
④ Post-poured zone
The post-cast strip is made into a straight seam, and the main reinforcement of the structure is not broken in the seam. When it is necessary to disconnect, the lap length of the main reinforcement shall be 45 times greater than the diameter of the main reinforcement, and additional reinforcement shall be added according to the design requirements. When the post-cast strip stops water in advance, the concrete in the post-cast strip will be locally thickened, and an external or embedded water stop will be added. The construction of post-cast strip shall meet the following requirements:
The post-cast strip shall be constructed after the concrete ages on both sides reach 42d, and the post-cast strip of high-rise building shall be constructed after the concrete pouring on the structural roof 14d.
The joint treatment of post-cast strip conforms to Article 4. 1.22 of Technical Specification for Waterproofing of Underground Engineering (GB 50 108-200 1).
Before the concrete construction of post-cast strip, the post-cast strip and external water stop should be protected to prevent them from falling into sundries and damaging the external water stop.
The post-cast strip shall be poured with shrinkage compensating concrete, and its strength grade shall not be lower than the concrete on both sides, and the curing time shall not be less than 28d.
7 basement waterproof project
The basement waterproofing project of this project is mainly for the engineering basement. Besides the reinforced concrete self-waterproofing, a flexible waterproof layer is added. The basement exterior wall is waterproof with 4 thick BAC double-sided self-adhesive waterproofing membrane, and the roof is 3 thick BAC double-sided self-adhesive waterproofing membrane. Specific waterproof methods are as follows.
8. 1 Flowchart:
Installation, reserved holes and pipelines are in place → Basic treatment →BAC waterproofing membrane (the outer protective film is not exposed) → Detail enhancement treatment → Protective layer construction.
8.2 Key points of construction
(1) Basic treatment: All pipe holes passing through the wall must be located correctly, installed firmly without looseness, and both ends should be smooth. The 10× 10 groove around the casing hole shall be filled with sealing material and then leveled with cement mortar; Chisel off the opposite screw hole on the outer wall and smooth it with cement mortar. After chiseling away the obvious pockmarked honeycomb, smooth it with cement mortar. All corners shall be made into uniform and smooth rounded corners with a radius of not less than 20 mm.
(2) The BAC coils are firmly bonded, and the lap joint meets the requirements of technical specifications.
(3) 3) The outer protective film of BAC coil, the waterproof cushion side of bottom plate and the waterproof outer protective film of outer wall are not exposed.
(4) For the pipe root, Yin and Yang angles and other parts, large-scale construction should be carried out, with one cloth and two additional waterproof layers with a width of 20-30cm.
8.3 construction matters needing attention
(1) Waterproof materials shall be visually inspected after entering the site, and can be used only after they meet the requirements.
(2) The grass-roots treatment shall be smooth and free from sharp protrusions.
(3) After laying the 3)BAC roller material, check and repair the local damage.
The construction scheme of the above-mentioned hospital foundation and foundation engineering was collected and sorted by Zhong Da Consulting Company.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd