I want to cover earthwork in civil engineering, but I don't know much about it! Ask the master to guide me how to do it.

Civil engineering summer vacation construction practice report (1) With the end of junior year, we ushered in the last summer vacation of college life, and we also made full use of this summer vacation to carry out practical activities. This internship is our first contact with the scene since we studied theoretical knowledge for three years. Its significance can be imagined, and we combine theoretical knowledge with practice for the first time. I came to the construction site to study without exception. 10 From July to August 20th, 2006, I learned a lot from the 40-day internship, which also allowed me to break through the limitations of books and truly combine theory with practice. The construction company I participated in the internship is the Third Construction Company of China Construction No.7 Bureau, which is an enterprise with a glorious history and tradition of 50 years. It belongs to the Ministry of Construction and China State Construction Engineering Corporation, and is a national large-scale first-class construction enterprise. During my internship, the company is undertaking the project of "Famous City, Harbor and County", including 43 residential buildings. Because of its large scale, I learned a lot during my internship, which is summarized as follows: (1) Project Overview: Project Location: No.88 Dongjiangbin, Mawei District, Fuzhou Construction Unit: Mingcheng Real Estate (Fujian) Co., Ltd. Construction Unit: China Construction Seventh Engineering Bureau. Construction area excluding basement: 442.79 square meters; Building length and width: 14.70m× 45.30m (no deformation joint); BuildingNo.: Ground Floor 12; Building height: 3.0m (1st to 9th floors) /3.45m (10th floors) /3.0m (11th and 12th floors). Building height: 36.90m Functional layout: residential building grade: Grade II reasonable service life: 50 years building fire protection: Grade II fire safety regulations, Grade II fire-resistant structural system: seismic fortification intensity of reinforced concrete frame-shear structure: 7 degrees building elevation: indoor 0.00 equivalent to absolute elevation (zero) 7.850m wall: external wall, household wall: 190 thick load-bearing hollow. Interior wall: 90, 190 thick non-bearing hollow brick. Exterior wall decoration: the large surface is brick, and the lines are mostly exterior wall paint. Interior wall decoration: cement mortar base roof (secondary waterproofing) 1, cast-in-place reinforced concrete flat roof (including small roof with room and hall at the lower part): waterproof layer: 3mm thick cement-based polymer waterproof coating, 3mm thick APP modified asphalt waterproofing membrane. Insulation layer method (polyester tire): 25 thick extruded foam insulation board, 40 thick C20 fine stone concrete, with 4@200 bidirectional steel mesh in the insulation board. See page 30 1 for the setting and practice of frame joints. Small roof with balcony or outdoor platform at the lower part: 20 thick 1: 2.5 cement mortar leveling layer, C20 fine stone concrete slope finding, waterproof layer: 3 thick cement-based polymer waterproof coating, and 3 thick APP modified asphalt waterproofing membrane. The waterproof layer (polyester tire) is made of 25 thick fine stone concrete and 4@200 bidirectional steel mesh. See page 30 1 for the setting and practice of frame joints. The owner's roof is non-slip floor tile (light color surface). Structural overview: structural environment category: the environmental category of the upper indoor concrete structure is category I, and the environmental category of the concrete such as roof, pile cap, ground beam and floor is category II. Seismic fortification category: Class C structural safety grade: Class II structural seismic grade: Class III frame seismic grade, seismic wall and coupling beam seismic grade: Class II foundation design grade: Class B foundation form: static prestressed high-strength concrete pipe pile concrete (C35 and above concrete adopts crushed stone grading). Cushion pile core cap beam 1 floor wall column 2 floor beam slab 2 floor wall column c15 C30 C30 C40 C35 3 floor beam slab 4 floor beam slab 5 floor beam slab 6 floor beam slab 7 floor beam slab 8 floor beam slab C25. C30 C25 C30 C25 C25 9-story beam slab 10-story beam slab/KLOC-0 1 1 story wall C25 C25 C25 C25 C2512 story wall column roof beam slab and its upper water tank others. The height of C20 structure of C25 C25 C25S6 dense concrete is 3.0m (1 floor 9)/3.45m (1floor 0)/3.0m (1floor,1floor 2). (2) Explain the main contents of the internship and the specific work I personally participated in: I learned a lot because of the long internship time, from the pile cap construction to the standard floor, which I personally participated in. However, because the pile foundation had been finished when I went there, I was deeply sorry that I couldn't get in touch with piling. The whole workflow is as follows: pouring pile core → pouring cushion → installing pile cap and foundation beam formwork → installing pile cap and ground beam reinforcement (including column reinforcement) → pouring pile cap concrete → backfilling foundation → welding column reinforcement → installing column and beam slab formwork → installing beam slab reinforcement → pouring beam slab concrete. The whole construction process also needs to include plane and elevation lofting. In addition to studying the construction of single building, I also assisted the deputy project manager to control the construction progress. The whole concrete structure engineering includes foundation engineering, reinforcement engineering, formwork engineering and concrete engineering. However, due to the rush of time, I didn't come into contact with roof engineering and decoration engineering during the whole internship. The following will summarize the knowledge I have learned in my internship and the projects I have participated in: foundation engineering: because foundation is the most critical part of the whole building, it is also the top priority of the project. It is very important to do a good job in foundation engineering, including earthwork excavation, piling, pile breaking treatment, pile cap and foundation beam construction, etc. Because the earthwork excavation and piling of the whole project have basically ended, there has been no contact during the internship. So the following is just a brief introduction. Due to the poor soil quality and thick muddy soil in this project, a large area of broken piles occurred during piling, and many buildings were seriously affected by broken piles. In this internship, I learned a lot of methods to deal with broken piles, mainly introducing the methods of manual digging piles commonly used in engineering: First, introduce the treatment process of broken piles. After pile completion and static load test, do dynamic measurement. After the dynamic test report comes out, you will know that the pile is broken at a depth of several meters. If the dynamic test report shows that the pile is broken at about 4m, dig a hole manually. Attention must be paid to safety in the process of manual excavation, which is very important for the protection of the hole. There are generally two kinds of retaining structures, one is between -0.00 m and-1.50 m, with concrete as retaining structure, and then generally with steel casing as retaining structure. When the pile is dug to a depth of 20 cm ~ 50 cm, the broken part of the pile is taken out by crane, and the prefabricated reinforcing cage is hoisted down. After alignment, concrete will be poured. The whole pouring process needs the cooperation of concrete mixer, crane and hanging basket, and workers also need to vibrate with vibrator. In the process of pouring pile, it takes considerable skill to pull out the steel casing. When pouring about 2 ~ 3 hanging basket concrete, iron liners should be taken out. After the pile is broken, the next procedure is to pour the pile core and pile cap cushion. In this process, the problem to be paid attention to is the control of concrete grade, and the concrete used for pouring needs to be added with expansion agent, because the pile cap and pile can be better connected together after the concrete is solidified. Special attention should also be paid to the formwork of the bearing platform. Because of its large volume, the spacing of the reinforcement system of the formwork of the bearing platform should be relatively small to prevent the formwork from expanding. The steel bar installation of pile caps and ground beams is also complicated, especially at the junction, which belongs to concealed works, so it is necessary to do a good job of inspection and acceptance. Reinforcement engineering: reinforcement is the skeleton of reinforced concrete structure, and it is integrated with concrete through gripping force. Reinforcement engineering is one of the three major projects of concrete structure engineering. The classification of steel bars can generally be classified according to different production processes, diameters and strengths of steel bars. The production process can generally be divided into hot rolled steel bars, cold rolled steel bars, cold drawn steel bars and cold drawn steel bars. According to different diameters, there are mainly the following kinds of steel bars: 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, etc. As far as strength is concerned, steel bars can be divided into HPB235, HPB335, HPB400 and RRB400 grades. Among them, HPB235 and HPB335 are the two most commonly used steel bars. Because it is difficult to check the quality of steel bars after concrete pouring, the steel bar project is a concealed project, which needs to be strictly checked in the construction process and the necessary inspection and acceptance system should be established. In order to ensure the normal operation of concrete structure in the use stage, the specifications and positions of steel bars must be consistent with the structural construction drawing. The construction process of general reinforcement engineering is as follows: structural construction drawing → drawing reinforcement sample diagram and filling in ingredient list → material procurement, inspection and storage → reinforcement processing → reinforcement connection and installation → inspection and acceptance of concealed works. The installation of steel bars requires workers' ability to look at pictures, and requires high kinds, quantities and positions of steel bars, which should generally be consistent with the drawings. In engineering, due to insufficient length or the requirements of construction technology, steel bars are often connected. Therefore, the connection of reinforcement is an important link in reinforcement engineering. Let me briefly introduce the three connection methods I learned today: 1, and binding connection: binding is still one of the main means of steel bar connection. When binding connection is adopted, its position and lap length must comply with the Code for Design of Concrete Structures (GB50204-2002), and binding joints shall not be adopted for longitudinal stress reinforcement of axial tension and small eccentric tension members. 20~22 fire wires or galvanized wires shall be used for steel bar binding joints, and they shall be bound together according to the minimum overlapping steel bar length specified in the specification. In this project, the beam-slab reinforcement is usually connected by binding, but it can't be used when the diameter of the reinforcement is too large, because it will have the adverse effect of eccentricity. 2. Welded connection: According to Code for Design of Concrete Structures, welded joints should be adopted for steel bar joints. The welding quality of welded joints is related to the weldability of steel and welding technology. Welding is divided into flash butt welding, arc welding and electroslag pressure welding. Among them, flash butt welding and electroslag pressure welding are commonly used welding methods in engineering. In this project, electroslag pressure welding is usually used for the connection of column reinforcement, while flash butt welding is used for the directly larger reinforcement in beam reinforcement. 3. Mechanical connection: Mechanical connection of steel bars is to connect two steel bar ends together by mechanical method. The beams and ribs in the basement of this project are connected by straight thread sleeves, and the quality of mechanical connection will be better than that of welding, but it is at a disadvantage in terms of construction cost and the cost is higher. Formwork engineering: Formwork engineering of concrete structure is a very important part of concrete molding construction. The formwork we are talking about actually includes two parts, one is the formwork that forms the shape and design size of concrete members, and the other is the supporting system that ensures the shape, size and spatial position of the formwork. The formwork shall have certain strength and rigidity to ensure that the concrete will not be damaged or deformed under the action of self-weight, construction load and concrete lateral pressure. The supporting system should not only ensure the accuracy of the spatial position of the formwork, but also bear the self-weight and construction load of the formwork and concrete, so it should also have sufficient strength, stiffness and stability to ensure that it will not sink, deform or destroy under the load. The materials and types of templates are also very different. Generally can be divided into this template, steel template, plywood. Plywood formwork is mostly used in this project, and steel formwork is used in some details, such as stair stepping, which is not easy to deform. The role of formwork is that in the process of structural construction, the concrete that has just been stirred from the mixer is in liquid state, and it needs to be poured into the same model with the shape and size of the component, and the required structural component can only be formed after the concrete is solidified and hardened. Formwork is a model used to form reinforced concrete structures or members. Most of the formworks in this project are long-span beam formworks, so the formworks and their supporting systems must meet the following requirements: 1, with firm installation and accurate dimensions, to ensure the section size and appearance quality of engineering structural members; 2. The supporting system has sufficient strength, rigidity and stability, and can reliably bear the weight and lateral pressure of newly poured concrete, as well as the load generated in the construction process; 3, simple structure and convenient disassembly; It is also convenient for the binding and installation of steel bars and the technological requirements of concrete pouring and maintenance. 4, template joints should be tight, shall not leak slurry; 5. This project adopts brand-new plywood construction; After four planned turns, the damaged and deformed boards will be phased out. Try to meet the design requirements, save materials and reduce costs. In the process of construction, the foundation of supporting system is often neglected, especially the bottom supporting foundation is often uneven, the sediment is not dense, and it is easy to sink under the upper load, which leads to slab deformation and insufficient flatness. Formwork support system is a temporary structure to ensure the shape and position of formwork panel and bear the dead weight of formwork, steel bar and fresh concrete and construction load. The vertical support of formwork mainly includes pipe supports assembled in dispersion, steel columns with height adjustable devices and portal frames that can be used independently. Before installing the template, the template needs to be designed and calculated. Generally, it is not necessary to design or check the commonly used structural types within its scope of application. Generally speaking, experienced contractors and workers know how to install them. However, some special structures, new system templates or general templates beyond the scope of application need to be designed or checked. Such as large pile caps and tower crane foundations. Otherwise, it is easy to swell. Concrete engineering: Concrete engineering includes preparation, transportation, pouring, maintenance and other construction processes, which are interrelated and influence each other. Improper construction of any process will affect the final quality of concrete engineering. Concrete preparation includes concrete preparation and concrete mixing, and each step is very important. The preparation of concrete also includes the design and construction of concrete. The construction mixture ratio is increased by a value according to the laboratory design mixture ratio, and the strength guarantee rate is 95%. The measurement of concrete construction ingredients must be accurate to ensure that the mixed concrete meets the design and construction requirements. The deviation shall not exceed the specification. The difference between construction mixture ratio and test mixture ratio lies in the difference of water content. Because the concrete strength value is very sensitive to the change of water-cement ratio. Because the actual water content of sand and gravel when the laboratory tries to mix concrete. In order to ensure the accurate water-cement ratio of concrete on site, the water consumption should be adjusted according to the actual water content of sand and gravel on site. Mixing of concrete, in order to obtain uniform concrete, raw materials must be fully mixed and thoroughly mixed. Mechanical mixing is generally used in concrete mixing in engineering, and attention should be paid to the control of mixing time and feeder time. Concrete pouring is the most important thing in concrete engineering. Only qualified pouring can ensure the strength and compactness of concrete meet the design requirements, ensure the integrity and durability of the structure, and ensure the accurate size, so as to ensure the smooth and bright surface of concrete after formwork removal. Before concrete pouring, it is necessary to do a good job in the acceptance of concealed works, and also check the size, axis, bearing capacity and stability of the formwork and its supports. The quality of pouring is also closely related to the technical level of pouring workers. If there is not enough vibration in the pouring process, it is easy to produce segregation, honeycomb, pits and even exposed tendons. The retention of construction joints is also a special process of concrete pouring. For some reasons, the whole structure can't be poured continuously, and the time of stopping pouring may exceed the setting time of concrete, so it should be determined in advance to leave construction joints in appropriate parts. Generally, construction joints should be left in the parts with small shear force in the structure, and the convenience of construction should be considered when applying. Progress control: The key to construction is how to control the progress, and how to arrange the time of mason class, steel bar class and woodworking class so that their working hours are staggered and there will be no conflict. Generally, the progress of a standard floor is as follows: column rebar vertical welding and column hoop installation 1 day → column formwork and beam slab formwork installation for 3 days → column concrete pouring 1 day → beam slab reinforcement binding for 2 days → beam slab concrete pouring 1 day. Among them, concrete pouring usually requires overtime or even overnight. The above progress is almost four sets (500 square meters) of commercial housing as an example, which takes 8 days. What the builder has to do is to coordinate the working hours of the three team leaders so that one party can't stop working. For example, in one day, one of the two buildings needs to be concreted, and the other needs to be concreted, so which one should be concreted first so as not to slow down the progress. Only the scheme of pouring column concrete first will be better. In fact, we should have avoided pouring concrete with two buildings. Internship for 40 days, check the progress almost every day. I should have more control over the progress, at least unconsciously. In the aspect of schedule control, I also learned how to draw horizontal schedule diagram and schedule network diagram. (3) New equipment, new materials, new technology and new technology adopted at the site: high-pressure pile connection: There are two methods to deal with broken piles, one is manual digging pile connection, and the other is high-pressure cement grouting pile. Manual digging pile is an obvious pile connection method for broken piles. High-pressure cement grouting pile is aimed at the pile that has been broken but not offset. Therefore, there is no need to use high-cost manual digging piles to connect piles. The steps of high-pressure cement grouting pile are as follows: 1. If the pile is broken at -4.00 m, a reinforcing cage with a diameter of about 6.50m must be made, and the pile insertion depth is about 6.00m, which is generally 2m larger than the broken pile position. 2. Fill the diameter of the pile hole with stones until it is filled. Thirdly, the mortar is poured into the pile core with a high-pressure machine until the whole pile is filled, and the broken parts of the pile can be almost connected. However, there may be some problems in this process, such as exposed mud during operation, which can't be filled, and the concrete hidden wall will be formed around the broken pile next door after solidification, which makes it impossible to press the steel retaining wall into the broken pile next door when digging a hole manually. (4) Problems existing in the construction site and suggestions for improvement: Safety: Safety is always the first and most important issue in the construction site. For the safety of this project, I attended the first meeting on the construction site, which was the summary meeting of the leaders of the head office to check the safety problems. At the meeting, the following points were mainly put forward: 1, power supply problem: the electrical box configuration of mixer and steel bar processing plant is not complete enough, and there is a danger of leakage and electrical contact. 2. Some scaffolding of seven floors are made of bamboo, and the monitor didn't choose the quality of bamboo, so with the increase of the number of floors and the increase of load, the greater the danger, especially the small bar. The leader also pointed out that although it is impossible to change it into a hard-core scaffold, it is best to choose the bottom material. 3. Scaffolding and formwork foundations are not very stable and may collapse, especially in rainy days. There are too many wooden houses, and they are not standardized. Workers build houses and live everywhere, and their lives are threatened, so the construction site cannot be standardized. The above safety problems are not only existing in this site where I practice, but also in many projects, so the safety of the site still needs to be further improved, and relevant departments should also strengthen supervision. Basement construction technology: the basement of this project is composed of three buildings, forming a large underground connection, and the building functions are parking lot and wartime civil air defense. This grounded platform and ground beam are templates made of brick walls (referred to as brick tire molds). Moreover, the 800mm wide post-cast strip is divided into five pieces and poured separately to prevent uneven settlement. And set up a number of intercepting ditches, so the amount of work is quite huge, and the whole 40-day internship has not seen much progress and change. Due to the influence of the fourth strong tropical storm, the soil in the upper part of the basement collapsed, the brick formwork was pushed down by the soil, and a group of workers were rebuilding the excavation. Because the technical level of basement construction is limited, and the degree of mechanization is not high, the safety measures are not in place, which also directly reflects the level of basement construction in China. Therefore, it is necessary for us to improve its construction level and mechanization level, and go out and learn from foreign advanced levels more, instead of blindly building cars behind closed doors. (5) Emphasize the harvest and experience of internship: 40 days of internship in the third company of China Construction Seventh Bureau is a process of combining theory with practice for me. Under the guidance of on-site construction personnel and technical leaders, plus my own efforts, I actively participated in the work, which made me have a deep understanding and mastery of the whole foundation practice and standard layer construction. But also have a deep understanding of all aspects of the whole civil engineering, and consolidate the knowledge in books from the actual construction, apply theory to practice, and enrich their theoretical knowledge. Although the whole internship process is short, I know how to be a good builder. The whole internship process also made me discover my own theoretical knowledge deficiency, and also made me full of motivation for future study. Although the construction site is a bit bitter, it also makes me understand a sentence: "You are a master if you suffer." . (6) Comments and suggestions on this internship: I am very grateful to the college and teachers for providing me with a good internship opportunity and letting me contact the scene and society for the first time. I not only learned how to integrate theory with practice, but also learned how to be a man. After 40 days of internship, I have matured a lot, but there are also some problems in acquiring knowledge. I sum up four opinions and suggestions on this internship (1), and the internship time can be appropriately increased. After all, although I can learn how to build the whole workflow in just 40 days, some details can't be deepened. (2) During the internship, some exchange meetings can be held appropriately. For example, in the middle of internship, some experience exchange meetings can be held in groups, and teachers can guide students, so that students can have a more purposeful internship in the second half, without the phenomenon of aimless internship. (3) Students can find a free time (such as weekends) to visit each other's projects and see how others do it. This can prevent them from becoming frogs at the bottom of the well, and also promote communication, take the essence and discard the dross. (4) If conditions permit, teachers can go to the construction site for investigation and guidance during students' internship, which can not only prevent students from being lazy, but also give them constructive guidance.