In recent years, after the reform of water pipe system, the shortage of project maintenance funds and the phenomenon of "light pipe reform" have been basically solved, the flood-fighting intensity of the project has been further enhanced, and the project management level and overall appearance have been further improved, which is inseparable from the high standard maintenance of river engineering in recent years. As an engineer and technician of a water management unit, I participated in the maintenance inspection and studied the maintenance standards of water conservancy, so I put forward some opinions for discussion.
Pay attention to the high standard maintenance of some rivers of the Yellow River. In the maintenance construction, the engineering procedure can be basically divided into several stages: pre-construction preparation, maintenance construction stage, main project construction quality control, construction process quality management, civilized construction and safe production, so that the whole project maintenance construction can be carried out in an orderly manner.
1. Preparation before construction
According to the actual situation of river engineering, the maintenance company can maintain the river engineering at the same time in order to ensure the smooth progress of the construction. All the quantities signed in the contract can be subdivided and arranged to be implemented by the engineering maintenance team, which will complete the maintenance tasks in sections.
1. 1 personnel organization: in view of the actual situation of the Yellow River waterway project, in order to gain the initiative in maintenance construction, the maintenance company scientifically arranges the maintenance teams and their maintenance personnel according to the location of the project and the size of the maintenance project, quantifies the division of labor among the maintenance personnel, implements the responsibility system for maintenance posts, and manages the maintenance teams separately. According to the requirements of the construction contract, the list of personnel and construction equipment, construction organization design and construction progress plan were provided to the supervision department. According to the construction procedures and related requirements, the related projects were re-surveyed, and the problems affecting maintenance and construction were reported to the supervisor and water management unit in time, which made full preparations for the smooth progress of the project.
1.2 Selection of control guide stones: In order to ensure the quality of control guide stones, we will organize special personnel to conduct field visits, select and purchase stones with hard texture and weight above 30kg, report them to the supervision engineer for approval, and sign an agreement to ensure the high-quality stones of the project.
2. Maintenance construction stage
The maintenance task is to maintain the integrity and aesthetics of the project. In the maintenance of pilotage control project, it is necessary to maintain pilotage control project frequently, deal with surface defects in time, and maintain the integrity, safety and normal operation of the project.
2. 1 peak maintenance. Maintenance requirements for dam crest of pilot control project: the dam crest shall be flat, free of water and potholes. The eyebrow soil should be cultivated neatly and firmly, and the earth-rock joint should be close, without potholes and joints. The drainage ditch is unobstructed, and there are no gullies, badger foxholes, tall weeds, scattered stones and other sundries. The reserve stones stored at the dam crest should be piled up and located in a suitable position, which is conducive to flood control and emergency rescue. The stone cribs should be more than 3.0m away from the abutment facing the water, the height of each crib should be between 1.0- 1.2m, and the dimensions of each crib should be consistent. Stacking should be flush, flat, dense, neat and beautiful. Before stacking, the top surface of the dam should be leveled with dry soil, and then each stack should be marked with white ash, and the stacks should be arranged evenly and neatly. At the same time, we should do a good job in greening, planting trees and grass, the trees grow vigorously, there are no pests and diseases, the turf is neat and beautiful, and the coverage rate is over 95%.
2.2 Dam slope maintenance. Maintenance requirements for dam slope of control and guidance project: the slope surface is smooth, free from rain outlets, thorns and weeds, and the stone slope protection is free from looseness, collapse, falling off, weathering, freezing damage or overhead.
(1) Soil and water conservation of dam slope: it is used to fill the rain mouth that has an impact on the soil slope at the downstream side of groin, the soil slope near and behind the earth dam river and the soil slope behind the Shi Lian dam river due to rain erosion.
(2) Dam slope maintenance: repair the damaged part of dam slope caused by engineering emergency rescue, root stone reinforcement, rain erosion and root stone loss. There are three main aspects in the renovation of dam slope stone: one is the renovation of loose stone slope protection. If Tan Shi slides down and falls off, the upper residual stone can be thrown to the falling part, then the top block stone part can be filled with new stone for protection, and finally the slope and the altar top can be renovated. If the dam tire soil is washed away by rain or river water, resulting in gullies and depressions on the slope surface, the stones in the depressed part can be removed and moved out, and the dam tire can be backfilled with clay, and then the slope surface can be backfilled with the removed stones. The second is the restoration of stone retaining slope protection. When the stone retaining slope is damaged by sliding, bulging, concave waist, etc., the damaged parts should be removed first, the sub-stone should be separated from the abdomen stone, and the filter pad should be removed. If there are large dam face holes and swallow nests, they should be filled with gravel to prevent water from scouring the cushion and dam tire soil and causing new damage. The third is the transformation of gravity mortar masonry slope protection. The damaged stones should be removed first, and the grouting joints of the stones should be washed clean according to the slope protection construction technology before renovation.
(3) Maintenance of drainage ditch: First, there are many obstacles to retaining water, such as dumping garbage, waste residue and other sundries into the ditch at will; Second, grazing, pit building and pit digging on the drainage slope caused accidents such as slope collapse and gap; Third, weeds are overgrown, which affects the smooth drainage. Therefore, the maintenance of the drainage ditch includes removing the sundries in the drainage ditch and repairing the partially damaged parts, and the seriously damaged parts should be updated. If the drainage ditch on the dam slope sinks or is damaged, the damaged part shall be removed, backfilled and compacted, and the dam slope and drainage ditch shall be repaired according to the original structure.
2.3 root stone maintenance. Root stone is the foundation for the safety and stability of Tan Shi and even the whole dam, and the slope is1:1~1:1.5. The erosion of dam banks is serious, and it is easy to cause root stone loss, root stone stabbing pain, root stone erosion and root stone collapse. When the slope or depth is insufficient, the whole dam bank may be in danger. So the daily maintenance of the root stone is very important. Its maintenance includes root stone detection, root stone reinforcement and root stone leveling.
(1) Root stone detection: According to the relevant regulations on root stone detection and management of river regulation projects, root stone detection can be divided into pre-flood, mid-flood and post-flood detection. The detection method mainly adopts artificial cone rod detection, and the trend of root stone is determined by point alignment. Before the flood season, the number of dams to be detected should be no less than 50% of the dams near Daliu. In the flood season, dams that have been near Daliu for a long time or show signs of danger should be detected in time, and the number of dams detected after the flood season should be no less than 50% of the total number of dams near rivers in that year.
(2) Root stone reinforcement: When the detected root stone slope is less than the stable slope, riprap, big stone or lead wire cage will make up for it. Throwing amount is calculated according to the measured average slope, designed stable slope, river bottom surrounding area multiplied by section control length. When the measured slope of root stone is steeper than 1: 1, it is necessary to throw root stone for reinforcement.
(3) Root stone leveling: refers to the root stone exposed after the water level drops in flood season or dry season. At this time, for incomplete or urgent riprap accumulation, it is necessary to remove the height, fill the concave and pick up the flat to repair. When looking for riprap mulch, big stones should be outside, small stones should be inside, and layered flattening should be staggered and extruded.
2.4 Maintenance of ancillary facilities. The ground for the berm is flat; the boundary is clear; the boundary ditches and ridges are neat and level; and there is no illegal soil borrowing and sundries. Signs (monuments) are firmly buried, with reasonable layout, standardized scale, clear, eye-catching and beautiful signs, and no damage or loss; The water gauge shall be free from damage, clear scale and no coating on the base shall fall off.
3. The main project construction quality control
3. 1 Earthwork
(1) dam foundation cleaning: the cleaning boundary exceeds the design sideline by 30cm-50cm, and the vertical cleaning depth of dam foundation reaches 30cm. All trees, weeds and other sundries within the scope of the project should be removed and transported away, and stacked within the specified scope.
(2) Earthwork filling: Earthwork filling shall be carried out after foundation cleaning. The soil must be qualified, without impurities, and the clod size meets the requirements. Should choose less viscous soil, should not use silt soil, impurity soil, expansive soil and dispersed clay. Pave to the specified position according to the specified requirements, fill horizontally, and do not fill along the slope, and the thickness meets the requirements; When working in sections, reduce joints as much as possible, and it is forbidden to leave bounded ditches; When the material is paved to the dam edge, a certain margin should be filled outside the design boundary, and the paving thickness and water content should be controlled. Frog rammer or steam rammer for rolling and tandem tamping. After rolling, the dry density and water content of soil are measured by nuclear instrument, and the construction of next working procedure is carried out after passing the inspection and being reported to the supervision engineer for approval.
(3) Impervious body construction: Impervious body is also called mud tire, and the soil quality should be cohesive soil, which must be filled horizontally in layers and compacted layer by layer manually or mechanically.
3.2 Stone Engineering
(1) Dry-set button face stone: Dry-set button face stone is made of high-quality stone, and each stone is processed by hand hammer and chisel, and the face is roughly square. If there is a crack in the middle of the stone, it must be opened, otherwise it shall not be used. The continuous use of stones less than 30cm in length shall not exceed four, and Shi Ding must be added at both ends. Avoid vertical straight seams, vertical seams and serrated seams. Dry button masonry slope is generally smooth, avoiding the phenomenon of "protruding belly and concave waist".
(2) Dry-filled abdomen stone: the abdomen stone is located between the dam tire and the top button face stone. Abdominal stone shall be buckled once every 1-2 level, and it shall be filled as it is laid. Abdominal calculus is lower than the tail of facial calculus. In order to protect the clay layer, the abdomen stone will pass through the riprap groove and be compacted layer by layer. The big stone will be compacted with small stones, and the feet will not move after the big stone is paved. Put a vertical stone every 2m2, and the vertical stone is 20cm higher than the plane of the abdomen stone, which is convenient for the combination of the upper and lower blanks of the abdomen stone.
(3) Rough riprap arrangement: Stones should be used along the direction, stubble should be pressed layer by layer, and the combination should be smooth. It is forbidden to use pebbles and peace pebbles. Cushion stones are not allowed in the first half. Try to avoid butt joint, no vertical seam; The slope is gentle and generally consistent, and there is no internal and external turning point on the flat surface.
(4) Scattered-root riprap: The stone weight is generally controlled at 25Kg~75Kg, and riprap is arranged in layers through riprap grooves, so that the internal and external stone stubs have the same thickness and the slope is smooth. 25Kg~75Kg of large stones are mainly used in the dam body, and stones below 30Kg are prohibited under water, and the total amount of stones around 25Kg is controlled at 10.
4. Construction process quality management
4. 1 In terms of engineering maintenance, we will further improve the construction quality assurance system, issue maintenance standards for water conservancy projects to maintenance personnel, and establish a maintenance post responsibility system. Designate a special person to be responsible for the key working procedures and important links of each unit project, and strictly control various factors affecting quality.
4.2 In order to ensure the quality of engineering maintenance, in the process of maintenance, the quality of engineering maintenance should be managed in an all-round, all-round and whole process, the relevant norms, regulations and quality standards of the Ministry of Water Resources should be strictly implemented, and the quality of materials, personnel and machinery should be strictly controlled.
4.3 Implement a comprehensive inspection system for project quality, set up a quality patrol inspection team, check the construction quality of each maintenance team from time to time, and make quality inspection records at the same time, so as to completely put an end to quality accidents.
5. Civilized construction and safe production
5. 1 Establish a security organization. In the process of engineering construction, the maintenance team should set up a leading group for production safety, provide necessary safety protection equipment for the members of the maintenance team, and formulate and implement safety measures to ensure the construction safety of the whole engineering construction site.
5.2 Do a good job in safety publicity. Organize construction personnel to seriously study the safety laws and regulations at higher levels, and make it clear that safety personnel should pay attention to safety. Among all construction personnel, actively carry out safety publicity and education, implement the policy of "safety first, prevention first", strengthen safety awareness, and attach importance to safety production ideologically.
5.3 Strict safety operation procedures. Strictly implement the corresponding safety operation procedures for each type of work. Construction personnel must wear effective safety protection facilities when entering the site, and safety officers at all levels should carefully carry out safety inspections before, during and after construction to eliminate or avoid potential accidents.
5.4 Carry out safety inspection. Full-time safety inspectors were set up on site. In accordance with the relevant principles, they focused on the inspection of working conditions, production equipment, on-site management, safety and health and the behavior of production personnel, and found that unsafe factors were completely eliminated.
In a word, in recent years, we have attached great importance to the high-standard maintenance and construction of river engineering, further strengthened the flood control strength of the project, and further improved the project management level and the overall appearance of the project.
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