Yuncheng Coal Mine Power Station in Shandong Province undertakes the air-conditioning cold and warm supply of administrative complex, canteen reception building, dormitory building of armed police squadron and office building, domestic water supply of living quarters, office and domestic electricity supply, hot water supply for employees' bathing and fire water reserve. The power station consists of three parts: refrigeration room, power distribution room, fire fighting and domestic water supply. There are many equipments, complicated pipelines, short contract installation period, narrow installation space and many civil interference factors. Because the equipment is purchased by Party A, involving many manufacturers, it is difficult to coordinate. The sketch of graphic design of this project is as follows:
Second, the difficulties encountered in project management
1. Install three heating, cooling and air conditioning equipment. The single equipment weighs 8.6 tons. Due to the special requirements of the equipment, it can neither be disassembled nor tilted. Forklift or forklift can't be used during transportation, only hoisting can be used. However, the site condition is that the clear height in the machine room is only 4m, and the crane cannot be deployed. The equipment entrance is near the fire pool in the north, and the transportation distance to the equipment foundation is more than 40m. At that time, the equipment foundation was 80mm above the ground. The construction space is narrow, and the internal wall construction is all interference factors.
2. Installation and welding of large pipelines. The equipment in this project has a heavy load, and the maximum pipe diameter reaches DN550, so it needs to be installed indoors. More pipes and limited activity space increase the difficulty of the work. At the same time, due to the long pipeline supply distance and high pressure, the welding requirements are also very strict.
3. Coordinate the technical guidance of other equipment entry time, equipment arrival and equipment installation. Because there are many equipment manufacturers, it is difficult to coordinate.
4. Plan of personnel, equipment and materials. There are many interference factors, tight construction period, limited working face, various materials and equipment, difficult planning and arrangement, and many variables.
5. On-site safety management. There are many layers of pipelines, special operations such as hoisting operation, welding operation, steam pipeline installation, high-voltage distribution equipment installation, etc., and there are many technical jobs, so the personnel who need to enter the site are complex, the personnel flow is large, and the management is difficult.
Third, the corresponding solutions
1. Aiming at the positioning problem of large-scale equipment in this project, the project management department held a special meeting, and invited the project manager, equipment manufacturer and site technical chief engineer with rich experience in construction management to participate in the formulation of specific special hoisting positioning scheme. Three schemes are preliminarily drawn up as follows:
(1) The construction unit belongs to the coal mine unit, with ready-made rails, steel flatbed cars and technicians. The first scheme is to borrow the relevant technical personnel from the construction unit, directly lay the track in front of the equipment foundation, and place the steel flat car on it, so that the equipment can be directly placed at the door of the computer room, and then manually pulled to the equipment foundation.
(2) The second scheme is to weld two ordinary channel steels on the equipment foundation, roll them onto the equipment foundation with forklift or logs, and then install the foundation.
(3) The third scheme is to transport the equipment to the foundation with a flat car with a lower base, and then unload the equipment to the foundation.
The difficulties encountered by the three schemes in site construction are as follows:
(1) When laying the rails, the ground in front of the machine room does not meet the laying conditions, so it is difficult to transport the equipment from the flatbed to the equipment foundation;
(2) The weight of the equipment is uneven from front to back, left and right, and it is easy to overturn, with great safety risks.
(3) It is difficult to get the equipment to the equipment foundation from the flat car, and the car is higher than the foundation, so it is in danger of overturning when it is unloaded.
After on-site analysis, the third scheme is decided after weighing the benefit and schedule requirements, so that it is faster to transport to the equipment foundation, and it is easier to unload from top to bottom than to hoist from bottom to top. During construction, because the equipment only has four legs on the ground and cannot slide, a mini-car with many rollers is used to roll under the four legs. In order to prevent the chain from rolling too fast, the chain is loosened bit by bit. In the order of arrangement, the first one should be transported to the easiest installation location, then the difficulty of the scheme should be weighed, and the most difficult one should be put in place, and then the other one should be installed.
2. Installation and welding of large pipelines. This engineering system has large water flow, large pipe diameter, the largest pipe diameter DN550, high installation position, close to the ceiling, and it is very difficult to install and weld. In the recent scheme, the pipeline welding groove is machined on the ground, and the V-groove is machined by beveling machine or gas cutting. After the pipeline is positioned, the groove is welded. First, the top and bottom of the pipeline are spot-welded and then butt-welded by two welders, which not only ensures the welding pressure requirements, but also ensures the welding speed and quality, and reduces the environmental impact on the weld. Double safeguard measures of temporary support and chain inversion are adopted for pipeline positioning to ensure accurate pipeline positioning.
3. In view of the large number of equipment manufacturers, the coordination with Party A's management personnel has been strengthened, and other equipment entry schedules have been listed, so as to obtain the support and cooperation of Party A and equipment suppliers. The principle is to advance the whole set of equipment first, the equipment that is not easy to disassemble, and then the equipment that can be disassembled. As the installation progress is gradually in place, try to get the equipment to the scene and you can enter the site. Equipment in place will not affect the installation of pipe network. The equipment procurement sequence of this project is: heating and cooling air conditioning units-high and low voltage power distribution equipment-two heat exchange units-refrigeration station pumps and other equipment-high and low voltage area heat exchange equipment-water tank-water pump and frequency conversion water supply equipment.
4. The project department should divide the responsibilities, make the responsibilities to people, and refine each construction process, with clear rewards and punishments at the same time. When the equipment is supplied by Party A, a special person will be arranged to coordinate the relationship between Party A and the equipment manufacturer to ensure that the equipment entry time is not ahead of time or behind time. Material procurement personnel are responsible for the phased supply of pipes, valves, thermal insulation materials, cables and bridges, and there is no backlog or lack of materials; The chief technical engineer of the project arranges construction personnel according to the construction operation surface to ensure that there is no slowdown or delay; The team leader of tools, instruments and mechanical equipment is responsible for writing down the demand details, and the project manager coordinates to improve the utilization efficiency of tools, instruments and mechanical equipment.
5. The safety risk of the construction site is caused by the unsafe behavior of people and the unsafe state of things. To control people's unsafe behavior, we need to sum up psychology and behavior, and improve people's consciousness and ability through education and training. The unsafe state of things must be improved by practical safety technology. As a complex system, building construction is directly caused by people, equipment and environment, while management defects are indirect reasons. There are many layers of pipelines in this project, including special operations such as hoisting operation, welding operation, steam pipeline installation and high-voltage distribution equipment installation. There are many technical jobs, complicated personnel entry, large personnel flow and difficult management. To ensure safety, the following measures are taken:
(1) Implement the policy of "safety in production, prevention first" and the principle of responsibility system for safety in production. The project manager is the person directly responsible for the safety production of the project, strengthening the safety inspection, and setting up special safety management personnel to carry out daily and surprise safety inspections. This project holds weekly safety warning meetings, emphasizing the importance of safety, putting people first and cherishing life.
(2) Implement the system of holding certificates for special operations personnel. Lifting operation, welding operation, steam pipeline installation, and pipeline installation of power transformation and distribution equipment can only be operated with a certificate of conformity within the validity period, and risk prediction should be strengthened and preventive measures should be formulated. During the hoisting operation, no other construction is allowed in the dangerous area; Protective measures should be taken for welding, and the power transformation and distribution equipment should be effectively grounded and live-line operation should be carried out.
(3) When jobs cross, ensure that the previous procedure is qualified before construction, and it is strictly forbidden to "switch to the next procedure as soon as the previous procedure is finished" in order to grab the progress.
(4) Carry out construction according to the approved construction organization sequence, with the upper layer first and the lower layer later, and arrange pipelines and cables; Connect the equipment first, and then take over the network; Pressure test first, and then construction of insulation layer and protective layer.
Fourth, summary.
Because the project is organized and managed in strict accordance with the construction organization design and special construction scheme, the problems encountered are solved in place and the measures are effective. At present, all the installation and debugging work has been completed as scheduled, and the trial operation has achieved good results. The pipelines in the machine room are arranged orderly, the pipe fittings are installed neatly, and all kinds of equipment are positioned accurately, which has been unanimously recognized and praised by the construction unit and supervision unit. To sum up, the equipment installation project should be based on various external conditions, combined with the difficulties of practical problems, carry out targeted analysis, and finally implement the correct solution, in order to achieve twice the result with half the effort.
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