Winter construction and insulation system

Winter construction and insulation system

I. Basis for compilation

1, reference

Code for Construction and Acceptance of Concrete Structures (GB 50204-2002); );

Code for Construction and Acceptance of Subway Engineering (GB 50299-1999);

Unified standard for construction quality acceptance of building engineering (GB 50300-2001); +0);

Code for Winter Construction of Building Engineering (JJ104-97);

Drawings of public underground circulation passage in Area A of Donghua City;

2. Climatic conditions

According to the statistics of temperature data in Beijing, the winter construction period of this project is1October 15 to March15 of the following year. During this period, the daily average temperature above the ground in Beijing is below 5℃, while the underground temperature is between 10℃ and 18℃ within 3.2m below the ground. Because the construction time of the public underground passage project in Area A of Donghua City is from June 8, 2006 to April 8, 2007, which happens to be the winter construction date, but the underground tunnel is 4 meters below the ground, so the operation procedures in the tunnel do not need to take winter construction measures, and the operation procedures above the ground only need to take winter construction measures.

Second, the project overview

This project is the connection project between the second floor of the public building in Area A of Donghua City and the existing tunnel. The building in Zone A of Donghua City is located on the east side of the existing Chongwenmenwai Street, and the existing underground passage is located under Chongwenmen Street, which is located on the north side of the building in Zone A of Donghua City.

The newly-built passage is a public underground second floor, which is connected with the existing street intersection in front of Hadmen Hotel. The maximum structure of the new passage is 5.02m, and the total length is about103.3m.. The north and south ends of the passage are connected with the existing crossing passage and apartment by open-cut construction (the wind turbine room and power distribution room are set in the open-cut section at the south end), with a total length of about 54 meters. The planned section under Chongwenmenwai Street is constructed by mining method, with a total length of about 49 meters. After reconstruction, the net height is 2.5m, and at the southern end of the passage near the apartment, a small air shaft on the ground of 1.2m× 1.2m is set.

Third, the purpose of preparation

1. Strengthen the technical management of winter construction and improve the technical management level.

2. Ensure the construction quality and avoid unnecessary rework, repair and waste of resources caused by improper technical measures.

3, to ensure construction safety, to achieve national, local and management company goals.

4. Take correct technical measures for winter construction, effectively reduce the project cost and improve economic benefits.

Four, the winter construction site and task

This scheme is applicable to the construction of the public underground passage project in East Huacheng Area A in winter (1 1, 12, 1, February and March). The specific arrangements are as follows:

Shaft construction: 2008165438+1October 20th -20081February 65438;

Construction of backfill section of underground excavation section: 2008 165438+20081October 20th ~ 2008 65438+February 10;

Pipeline construction in underground excavation section: from 2008 12 to 200910;

Construction of underground excavation section crossing the existing hotel section: February 200910 ~ March 20, 2008;

Construction of open cut section on the north side: March 20, 2009 ~ April 20, 2008.

The preparation of verb (verb's abbreviation) for winter application

1, personnel organization

Set up a winter construction leading group with the project manager as the team leader, the deputy project manager and chief engineer as the deputy team leader, and the heads of various departments and work areas as the team members, and be responsible for the organization and coordination of all aspects of winter construction of the project management department. The organization chart of winter construction leadership is as follows:

Among them, the team leader is generally responsible for organizing and coordinating all aspects of winter construction of the project management department and three work areas.

The deputy team leader is specifically responsible for the site winter construction management and technical work.

Each team member is responsible for implementing the specific work of winter construction of each department.

Block diagram of winter construction leading group

Team leader: Zhang

worker

travel

Pipes/pipes

reason

department

Wei quanxing

machine

tool

thing

money

department

liu guanghui

Security captain

Li shuifa

head office

A country in the Zhou dynasty

tiger

safe

quality

department

majority

Horizontal ground

Deputy leader: Duan Ji

day shift

Monitor: Wang Yongrong

night shift

Monitor: Liu Yongqiang.

Engineering laboratory

plum

2. Organizational measures

(1) Before the arrival of winter construction, the technical director shall make a scheme disclosure to the management personnel of each work area, and the technical director and technical office of the work area shall make a written technical disclosure to the construction personnel according to the winter construction scheme. The management personnel of each department shall, according to their respective responsibilities, arrange the preparation work before winter application.

(2) The materials department shall make preparations in advance according to the winter application material plan to ensure that the materials and equipment needed for winter application enter the site on time and as planned; The personnel department arranges the winter construction personnel, and conducts safety training and assessment for special types of work such as thermometers together with the engineering and safety departments; The engineering management department and the technical office of the work area are responsible for the preparations for the on-site winter construction.

(3) Before entering the winter construction, specially organize relevant personnel such as temperature measurement and heat preservation to conduct technical business training, learn relevant knowledge within the scope of work, and clarify responsibilities. Only after passing the exam can they go to work.

(4) Understand the recent weather changes, receive the weather forecast in time, and prevent the cold current from suddenly attacking.

(5) Assign special personnel to measure outdoor temperature, mortar and concrete temperature during construction, and make records.

3. Site preparation

(1) Mechanical ministry of materials and equipment and the electrician in the work area inspect, repair and maintain all kinds of mechanical equipment, electrical equipment and lines to ensure the normal construction in winter.

(2) According to the physical quantity, organize relevant machinery, additives and thermal insulation materials to enter the site in advance.

(3) The temporary water supply pipes and building materials on the construction site shall be insulated against freezing.

4, material preparation

(1) Conduct a detailed market survey on the production, supply, price and variety of various material resources, so as to contact the supply and demand as soon as possible and implement the supply and demand requirements.

(2) According to the construction progress and material consumption plan of the project, do a good job in the application, ordering and procurement of materials, organize the materials to enter the site as planned, and do a good job in storage.

List of winter construction materials and equipment

serial number

Name of materials and equipment

model

amount

comment

1

Thermal insulation waterproof tarpaulin

2000㎡

2

fire

1000

three

straw bag/sack

1000

four

Hot water tank

4m3

1

five

air heater

1 unit

six

generator

200 kV

1 unit

seven

thermometer

Mercury

20

eight

dry-chemical fire extinguisher

10

nine

Huojia

2 pairs

10

Barrier quilt

50 ㎡

1 1

electric blanket

70㎡

Six, winter construction measures

1, sand and gravel for heat preservation and cold protection

(1) Cold protection measures before raw materials enter the site

The sand and gravel used in winter construction requires little water content and almost no water. According to the requirement of water content, the Materials and Equipment Division of the Management Department specially sent people to inspect and contacted a number of sand and gravel manufacturers, and the required sand and gravel must meet the requirement of water content of sand and gravel. If the water content of stone is high, the method of on-site drying is adopted and then transported to the site after drying. Materials in each work area strictly control the quality of materials and resolutely control the water content of aggregates. Aggregates entering the site must be dry sand and dry stone, and water-containing aggregates are strictly prohibited.

(2) Heat preservation measures after materials enter the site

After the sand and gravel are transported to the site, it is fully enclosed and insulated. The lower part of the other three sides of the discharging enclosure is built with a brick wall with a height of 2 meters, and the upper part is built with a steel pipe for rain and snow protection. After the sand and gravel are loaded into the block, they should be leveled by manpower in time, and then the quilt should be covered in time with a thickness of 3㎝. The sand pile is covered with two layers of quilts with a total thickness of 6㎝, and the upper and lower layers of quilts are covered with shed cloth to prevent the quilts from being damaged and soaked. During the construction period from 65438+February to 65438+1October when the temperature in Beijing is the lowest, in order to ensure the temperature of aggregate, an electric blanket was laid between two quilts and heated in time to ensure the discharging temperature of aggregate.

(3) Cold protection measures before using the mixture

Due to the low temperature above the ground, the mixture used to spray concrete is stirred in the ground mixer. In order to prevent the mixture from cooling on the ground for a long time and affecting its use, it is immediately sent into the hole through the conveying pipe after mixing, so as to keep the temperature of the mixture and ensure the quality of sprayed concrete.

2, steel and steel processing cold.

At negative temperature, with the decrease of temperature, the yield point and tensile strength of steel bars increase, while the elongation and impact toughness decrease. In order to ensure the construction quality of reinforcement engineering, the following measures are taken for reinforcement construction in winter:

(1) raw materials, semi-finished products and processed finished products of reinforcement must be covered with tarpaulin;

(2) Facilities sheds must be built in each work area, and warm air should be used in the shed to avoid the construction of steel bars outside the shed. When construction must be carried out outside the construction shed, the weld and heat affected zone should be cooled slowly; Welding joints are insulated by slag; When the wind force exceeds Grade 4 (5.4m/s), windproof measures must be taken. It is forbidden to carry out any welding operation below -20℃;

(3) When carrying out lath or lap arc welding at negative temperature, adopt multi-layer temperature control welding process to prevent the cooling after welding from being too fast or the joint from overheating. The first layer of weld starts to arc from the middle, and then arcs to both ends; During vertical welding, the arc is transported upward from the middle, and then from the lower end to the middle, so that the steel bar at the end of the joint is preheated, and then the temperature of each weld is controlled in layers. The interlayer temperature is controlled between 150 ~ 350℃ to slow down the cooling. The welding current increases slightly, and the welding speed slows down appropriately;

(4) During welding construction, avoid burns and nicks, which are easy to be damaged at negative temperature;

(5) Joints with uncooled welding buckles shall not contact with ice and snow;

(6) The processed steel bars should be kept indoors as far as possible. If it must be placed outdoors, it should be covered with tarpaulin after overhead to prevent the surface from freezing. Binding reinforcement should be installed in place as soon as possible. And before concrete pouring, remove the ice and snow on the steel bar;

(7) During the construction of the concealed excavation section of the Austrian-Austrian section and the Xiong 'ao section, as far as possible, as many steel bars and grilles as possible will be transported into the hole in advance to keep it consistent with the temperature in the hole.

3, concrete construction

(1) cold protection of sprayed concrete

(1) Strengthen the management of raw materials, set up a steel truss material warehouse, and fill it with half brick walls around it to prevent rain and snow damage and prevent materials from being affected with damp. Cement and steel should be padded with wooden pillows and stored in the material warehouse with an overhead distance of 0.3m from the ground.

(2) In order to ensure the strength of concrete, the shotcrete used in underground tunnel is transported to the hole in time after the ground mixture is mixed, which is consistent with the temperature in the hole;

(3) Do a good job of ground water tank and water pipe to ensure that the water used for underground shotcrete is kept at a high temperature.

(2) Cold protection of commercial concrete

(1) If frost-resistant concrete is needed, design the frost-resistant concrete in advance, and attach the concrete mixture ratio and corresponding test report;

(2) The concrete is transported by a pump truck, and the concrete delivery pipe is insulated by a fireproof straw curtain wrapped with plastic sheets, so as to shorten the concrete transportation time as much as possible;

(3) The concrete pouring time should be arranged between 10: 00 am and 16: 00 pm on sunny days;

(4) Before pouring concrete, the snow, ice and dirt of formwork and steel bars should be removed, and the containers used for transporting concrete should have heat preservation measures to ensure the temperature of concrete entering the mold;

⑤ In order to ensure the construction quality of concrete, it is required to test the mold-entering temperature of each vehicle on site, which must be no less than 5℃, otherwise it is required to return it immediately;

4, waterproof layer construction

1, waterproof materials shall be stored overhead, not less than 20cm from the ground, and anti-freezing measures such as quilt cover shall be taken. There is no water in the storage place of bentonite waterproof blanket.

2, laying base surface can not have Mingshui, if there is any water seepage point must be blocked dew processing. During leveling layer construction, ensure that the construction temperature is not lower than 5℃.

3, waterproof layer construction to ensure that the grassroots level off firmly, clean and dry.

4, ECB waterproof board construction must ensure that the construction temperature is not lower than-10℃.

5, polyurethane waterproof layer construction, ensure that the construction temperature is not lower than 5℃, rain and snow weather and gale weather above level 5 shall not be carried out.

5. The ground on the construction site is cold and stagnant.

The construction water in the construction site is stored in the ground masonry pool, and the self-weight of the water is input into the tunnel through the pipeline for various construction operations. Domestic water is directly used through water pipes connected to the municipal water supply company. Because the domestic water pipe is buried below freezing point, it can avoid freezing crack by doing a good job of cold prevention for doors and outlet valves.

Construction water must be kept warm in pools and water pipes.

There is a 5㎝ thick asbestos insulation board around the pool. The pool is covered with a cover, which is also covered with asbestos insulation board to ensure that the water temperature in the pool is kept between 10℃ and 18℃.

Water pipes are mainly distributed on the ground and in the foundation pit, which need cold protection and heat preservation, and two layers of asbestos heat preservation sections are used for cold protection.

Water tanks and water tanks are used to store construction water, and water is pumped into the tunnel through pipelines, so it is not necessary to take cold-proof measures for water pipelines in the tunnel. Domestic water is also connected to the water company's pipeline. The water tank, water tank and water pipe are all made of 5㎝ thick asbestos insulation board and two layers of asbestos insulation board, all of which are covered with cold protection.

6. Cold protection of mechanical equipment

(1) The air compressor is enclosed by colored steel plates, with built-in tarpaulin for cold protection and heat preservation;

(2) Hanging a layer of quilt insulation layer on the inner side of the existing fence of the mixer, and hanging a layer of cotton curtain at the entrance to keep out the cold, so as to ensure the temperature of the stirred materials;

(3) The electric hoist shall arrange special personnel to check the wheel rim and wheel rail of the walking part, the bearing part and the wire rope twice a week, and timely repair the cracks to prevent brittle fracture;

The cold protection of machinery and equipment shall be implemented to people, and antifreeze shall be used for the cold protection of water tanks in machinery to ensure the normal operation of machinery every day.

7, other cold measures

Thermal insulation materials mainly include: shed cloth, quilt, colored strip cloth. The shed cloth and quilt are processed according to the technical requirements. The main technical index is the thickness. The thickness of the quilt is 6㎝, and each layer is 3㎝. The quilt is not translucent. The thickness of the shed cloth is 0.3㎝.

The technicians in each work area will assign special personnel to measure the temperature three times a day in the morning, at noon and at night. The temperature measurement items include: the temperature in the ground and open pit, the temperature in the underground tunnel, and the temperature of sand, gravel, water, cement, sprayed mixture and commercial concrete when they are taken out of the tank and put into the mold. Keep abreast of weather changes. When the weather is fine during the day, you can open the tarpaulin and quilt and cover it at night. In case of windy weather, the materials shall be loaded from a corner of the pile during construction to prevent the quilt from being blown up by strong wind. Shotcrete construction time should be arranged as far as possible at noon when the temperature is the highest. Steel bars should be covered with striped cloth, and the snow covered on striped cloth should be cleaned in time in snowy days.

Seven, winter construction safety assurance measures

1 During winter construction, anti-skid measures should be taken, and the living and construction roads and ramps in each work area should be cleaned frequently by the management department.

2. The drainage system set in the construction site of each work area is connected with the municipal sewage pipe network. It is strictly forbidden for the construction sewage to overflow with the construction site, causing the road surface and the construction site to freeze and causing unnecessary accidents.

3. Set a steel fence around the open-cut foundation pit and the construction shaft to clear the ice and snow around the foundation pit in time. Special escalators are set at the lower foundation pit and shaft, and anti-skid strips are installed on the steps of the escalators.

4. Assign special personnel to check and clean up the construction site every day. If any potential danger is found, it is required to deal with it immediately, including clearing the snow and ice on the construction site and roads.

5, aerial work personnel must fasten your seat belt, wear non-slip shoes. Scaffolds and pedestrian walkways should be laid with sacks or straw mats, and gantry cranes should climb ladders to bind straw bags and rope packages.

6, teams send electricians in snowy days, in order to prevent the lines from freezing in the snow and ice, after the snowstorm, check the power supply lines to prevent electric shock accidents caused by broken wires.

7. In order to avoid fire, it is strictly forbidden to use open fire and electric stove to keep warm in living quarters and work sheds, and make regular inspections. Set dry powder fire extinguishers in warehouses, construction sheds and office buildings.

8. During the curing period of concrete shed, smoke or burning gas should be discharged to the outside of the shed in time, and smoke poisoning prevention and fire prevention measures should be taken.

9, presided over by the trade union, organize employees to learn and popularize knowledge of safety in production, in order to enhance employees' awareness of construction safety and improve safety production technology.

Eight, concrete quality inspection and curing temperature detection method

1, quality inspection

(1) Before concrete pouring, check the preparation quality of pouring base surface, the installation quality of reinforcement and formwork, and carefully record the inspection results.

(2) After the commercial concrete comes into play, there should be a notice of opening appraisal and construction mixture ratio, and there should be concrete label, slump, initial setting time and mixing time.

(3) Self-mixed concrete shall be inspected at least twice per shift for composition materials and mixing methods.

(4) The concrete slump shall be inspected at least twice per shift, and the commercial concrete shall be inspected at the mixing station and pouring point respectively.

(5) Check the production of concrete specimens.

(6) After concrete pouring, carry out the following quality inspection:

(1) Check the appearance of concrete after curing, formwork removal and formwork removal.

(2) Conduct corresponding concrete strength tests for key working procedures of important structures.

(3) The strength and quality of concrete should be evaluated according to the strength of concrete specimens.

2. Check the temperature of water, admixture and aggregate added into the mixer, as well as the mixing and pouring of concrete, not less than 4 times per shift.

3, concrete curing temperature detection times

(1) During tunnel maintenance, it shall be inspected every 12 hours 1 time.

(2) Regularly observe the outdoor temperature and the environmental temperature of the construction site, four times day and night. Generally, the highest temperature and lowest temperature time should be listed as observation time.

Block diagram of winter construction quality assurance system

Winter construction quality assurance system

Personnel quality system

We must have the heart to ensure the winter mission.

We should have the heart of quality first and customer first.

Have professional knowledge of winter application.

Experience in winter management is required.

We should be good at investigation and study, sum up and improve.

There should be a strict and efficient organization.

A clear division of responsibilities between departments.

Strict working procedures

Winter construction should have quality evaluation standards.

There should be a complete and reliable management method to ensure the quality and progress of winter application.

There should be a perfect production and quality feedback system.

Product quality system

Nine, winter environmental protection and civilized construction guarantee measures

1. In order to avoid air pollution, electric heating is used for on-site heating.

2. In order to reduce the pollution to the surrounding environment, commercial concrete should be used as much as possible. For concrete that must be mixed on site, it should be mixed with it, and it is not allowed to throw it around. After completion, the site must be cleaned to avoid freezing.

3. Concentrate the domestic garbage and transport it to the designated garbage dump regularly.

4, before the mechanical construction to do a comprehensive overhaul of machinery, must be equipped with silencing equipment. Try to avoid oil leakage. Arrange assembly line operation during construction, and try to avoid mechanical assault production, causing urban noise pollution.

5. For each construction project, civilized construction should be implemented to each project leader, and the project should be completed from beginning to end.

6. The buried drainage system is connected with the municipal sewage pipe network, and it is regularly checked for dredging, heat preservation and cold protection, so as to ensure smooth drainage all the time.

7. Clean up the site regularly and keep it clean and tidy. Fences and temporary enclosures should be neat, fixed and stable to avoid dumping and hurting people in windy weather.

8. Clean up the surface snow in time after the snow, and pile it up at designated places if it is temporarily impossible to be transported abroad.

Ten, winter construction management

Before entering the winter construction, arrange the production plan as planned and do a good job in wintering maintenance. The engineering department of the project department and the technical office of each work area should combine the tasks of each work area to arrange the production plan in a unified way. Prepare in strict accordance with the winter construction preparation requirements, accept the inspection and acceptance of relevant departments, and urge to solve the problems found in the implementation inspection. In the winter construction process, the construction should be carried out in strict accordance with the requirements of Technical Regulations for Winter Construction and the principles and construction methods for determining the winter construction scheme.

In the whole winter construction process, each construction project should organize special personnel to carry out temperature measurement, and the person in charge of temperature measurement should inform the person in charge of the site every day so as to take immediate measures in case of abnormal situation. Finally, the temperature measurement records are classified into technical files by technicians. Temperature measurement project: During the whole winter construction process, the minimum and maximum outdoor temperatures are measured every day. Concrete mixing and pouring temperature: The temperature of concrete raw materials, pouring temperature and pouring temperature are required to be measured at least four times in the first shift. Curing temperature of concrete.

Concrete demoulding and concrete block construction in winter. The concrete demoulding must be based on the strength provisions in Code for Construction and Acceptance of Concrete Structures. The structure must meet the freezing critical strength of 4Mpa before demoulding. The demoulding of concrete can be controlled by the same test block. However, if the concrete is not demoulded, it must be approved by the on-site technical director and go through the formalities.

Before entering the winter construction, the project manager shall organize production, technology, safety, fire protection, quality and other departments to inspect the projects under their jurisdiction, and conduct acceptance according to the site preparation. Winter construction can only be carried out when winter construction is well prepared, but the problems found must be solved and implemented one by one in the construction. For projects that are not fully prepared, winter construction cannot be carried out, and construction can only be started after re-inspection.