The construction of a country's water conservancy project represents the economic development strength of the country, and it is related to the personal property security of all the people. Quality of a national water conservancy project construction is influenced by many factors, in which anti leakage technology plays an important role in the factors that affect a large number of quality, if there is a problem of water leakage in hydraulic engineering, the whole project will be subject to tremendous impact.
1 engineering seepage problem and reason analysis in water conservancy project.
Water conservancy project and other projects, more attention to the overall safety and seismic capacity, in the safety and seismic capacity of the problem is particularly important for its leakage problem. Leakage in water conservancy projects, not only caused huge losses in economic expenses, but also often lead to the overall project paralysis, resulting in personal injury and death. The following is the frequently appeared in the water conservancy project and its causes of leakage problems.
1.1 the structure and technology of the project is not reasonable.
The existing water conservancy project in our country is in the middle of the last century, due to the effect of the comprehensive national strength, technical level, economic status, educational level at that time, compared to the construction of water conservancy project on the whole and in today's society of water conservancy project construction structure and technology, and in some defects.
1.2 construction facilities are not perfect.
Construction facilities are not perfect, water conservancy project leakage prevention technology is not up to the standards, grouting technology has not reached the designated requirements, are the cause of leakage. Another cause of the leakage of water conservancy project is the construction of water conservancy projects in the material did not meet the specified requirements.
1.3 before and after the construction management problems.
Water conservancy project is another important reason for the leakage problem is in the construction and management of the existence of defects, management is not in place, resulting in construction in each phase of disjointed, no continuity, resulting in water conservancy project appear leakage phenomenon, did not reach the expected effectiveness. There is also a kind of construction in the water conservancy project construction only focus on the quality of the construction, the project after the completion of the work of the maintenance of the project, which leads to irreversible consequences. Like flood occurred in 1998 and in many parts of the levee is because termites Zhushi leakage occurred, causing irreparable disaster.
Through the analysis on the problems appearing in the above water conservancy project construction process, the author of water conservancy project in the project leakage problems proposed two solutions: 1. Cutoff wall technology application; grouting anti leakage technology application. The author starts from these two aspects, and makes a detailed analysis on how to solve the leakage problem.
2 cutoff wall technology.
2.1 characteristics of cutoff wall technology.
1) durability of the use of impervious wall technology of the casting of water conservancy project, in the case of technical standards, the service life and durability are slightly increased [1].
2) the permeability coefficient of the water in the small cutoff wall technology is obviously decreased.
3. The thickness of the wall of the concrete can be effectively controlled by the wall thickness of the wall, so that it can be the most economical as far as possible when the condition is allowed.
4) the unit area cost is low compared with other technologies, the use of cutoff wall technology in the cost of cost more benefits.
2.2 technology of cutoff wall.
2.1 2 impact into slot method.
2 1.1 steps 2.
Steps of the impact into the slot method:
1) hole making. Making holes in the dam with impact drill.
2) fill in the concrete. Put the concrete into the hole.
3) even slot section. Connect the holes in the dam to the concrete.
4) water injection into wall. Inject water into the concrete to make it a part of the wall.
5) the same method of casting another section of concrete wall, connecting to become a continuous concrete cutoff wall.
2 2 characteristics of 1.2.
The impact method is suitable for a wide range of formation, and it can be used for all kinds of strata, and the equipment in this method is simple and safe, and has a high quality level. However, this method because the program is trivial, so it takes a long time, the construction efficiency is not high.
2 2.2 grab slot method.
2 2.1 steps 2.
Grab trenching method:
1) section: hydraulic grab dredging machine dug with slot actual length and width, high demand.
2) into the concrete: first in the dug well in the groove of the injection of the right amount of mud, after watering, so that the formation of concrete walls, to ensure its stability.
3) the same method of casting another section of concrete wall, connecting to become a continuous concrete cutoff wall.
2 2 characteristics of 2.2.
Grab bucket trough method in water conservancy engineering use not only fast, but also has the advantages of high efficiency, in the level of soil and sand more use, should not use in rock more places.
2.3 2 saw slot method.
2 3.1 steps 2.
Saw cell wall step:
1) slot: slot machine to use the slot and the use of positive / reverse circulation to eliminate impurities in the slot.
2) injection of concrete: in a good groove into the mud and water injection to form a concrete wall section, so that it is stable.
2 2 characteristics of 3.2.
Because of the use of slot machine operation, the cutting method of cutoff wall technology can not be intermittent, and can be built in a continuous groove, not only the construction speed is fast, but also the quality of the project is higher.
2 2.4 waterjetting.
2 4.1 steps 2.
Waterjetting steps into the wall:
1) slotted: using slotted hole making machine, mixer, casting machine, using hole making machine spray ultra high water cut, 2) inject concrete: into the mud to make it stable, and finally into the concrete.
2 2 characteristics of 4.2.
Water jetting anti-seepage wall technology due to the use of hole making machine, mixer, pouring machine operation, so that engineering efficiency is improved obviously. This technique applicable to more sand strata.
2 2.5 2 2 5.1 step chain bucket.
Chain a battle of wits into wall steps: borrow by slotting machine, through slot machine driven into the groove of the row pile chamfer, into the mud to make it stable, and finally into the concrete.
2 2 characteristics of 5.2.
Technology of impervious wall chain often slotted spars in 40 cm width.
2.6 2 long deep mixing method.
2 6.1 steps 2.
Long deep mixing wall forming step: long deep mixing method of seepage control technique is by mixing pile machine from the different position of the drill into the dam, and cement slurry is injected into the holes in the dam, the cement slurry and soil formation of cement soil pile, diaphragm wall [2].
2 2 characteristics of 6.2.
The deep mixing method is mainly applied to the clay soil layer, which not only has low construction cost, but also is easy to operate.
2.7 2 plastic concrete.
2 7.1 steps 2.
Plastic concrete technology steps using grab and impact drill to divide the slot, can not be groove segments is too long, not too short, divided in a reasonable position to improve its robustness, complete division of slot into the concrete, and the use of helicopter pilot irrigation to water under the surface of the concrete is, to ensure that the tool is able to get the cooling and lubrication.
2 2 characteristics of 7.2.
Plastic concrete technology characteristics of bentonite and construction materials in a better material, this method using bentonite cement replacement and improve the anti-seepage project, using the performance and quality of the project, the overall project longer service life.
2.8 2 vibration into a wall.
2 8.1 steps 2.
The mold, through the vibration of the form will be sunk in the soil, arrived at the designated depth stop and pull out after the formation of the slot, in the slotted holes into the mud, the formation of cutoff wall.
2 2 characteristics of 8.2.
Diaphragm wall seepage control wall technology is widely used in the construction of water conservancy project. This method is less influenced by external factors, so it has a high impervious and durable.
3 grouting anti leakage technology.
Grouting anti seepage technology is currently used more generally to an anti leakage technology. It can not only be used a wide range, and advanced technology can greatly shorten the construction cycle is completed, to some higher quality requirements and construction technology requirements engineering can also be applied. Grouting anti seepage technology of grouting requirements more stringent, the grouting material shall be non-toxic harmless, not to people and the environment, harm; should be in the use of the environment is stable and reliable, is not easy to change; need to have good mobility, cured after filling into the hole.
3.1 high pressure jet grouting anti leakage technology.
1.1 3 high pressure jet grouting anti leakage method and characteristics.
High-pressure jet grouting anti seepage technology by high pressure water jet grouting pressure is enhanced, structure damage of the formation, make the combination of cement slurry and the formation of sand particles, forming a solid solid, leak proof function, but also improve the bearing capacity of the foundation.
1.2 3 high pressure jet grouting to prevent leakage of the advantages.
High pressure jet grouting anti leakage technology and concrete cutoff wall technology in irrigation increased, in engineering cost cost saving, the use of facilities and equipment is simple, flexible, easy operation, short construction cycle, reliable connection to meet the needs of different levels.
3 2.1 project controllability is better 1.
High pressure jet grouting anti seepage technology in drilling and grouting is more controllable, through the computer control, can more accurately grasp the position and depth of drilling, by easy operation of the device, according to a predetermined standard for open hole and improve the controllability of engineering. At the same time, the high pressure jet grouting technology, the use of high pressure jet principle, the larger gaps in the formation, the use of the material to fill the preferred material to improve the quality of anti leakage.
1 2.2 3 to expand the scope of use, more reliable connection.
High pressure jet grouting technology based on different strata structure have different solutions, can be used in the project before, during and after the three periods, to improve the application of anti leakage technology. By high-pressure jet grouting anti leakage technology for casting the wall, with better anti permeability and reliability, in connection with other engineering equipment and stable is also improved.
Quality control of 1.3 3 high pressure jet grouting.
Impervious wall verticality is in high pressure jet grouting anti leakage technology should pay special attention to a problem, for problems timely rectification; high pressure jet grouting anti leakage technology needs to pay attention to the requirements of the quality and the quantity of cement, with a minimum of input get maximum benefit; staff should, do a good job of construction process of records, so well documented.
3.2 Dam Splitting Grouting technique.
Split the dam splitting grouting technique is according to dam the physics mechanics rule, with the mud pressure will dam split, and the cracks into the mud so as to be combined with the original dam, dam seepage control function of a technology with. Actual situation of this technology in need of attention of splitting grouting in the dam, the construction quality is good can only in splitting grouting, if the quality is poor, you need to across the board grouting. It not only can improve the anti-seepage performance of the dam, and save the cost, improve efficiency in the use of the funds.
3.3 curtain grouting technology.
The technology of foundation curtain which is based on the sand and gravel foundation of the dam is called curtain grouting technology. This technique in the curtain at the bottom of the deep water rock in, and the top of the dam or concrete gate connection, which can effectively reduce the infiltration of ground water, and drainage system and foundation curtain interaction can reduce the impact of water flow on the dam.
4 knot language.
Leakage prevention project plays an important role in water conservancy project, anti leakage works well, the water conservancy project construction, the drawbacks will be reduced, the quality of water conservancy project is bound to have a qualitative leap. In the water conservancy project before and after the construction of each stage, it is necessary for each staff to be taken seriously, this is any one of the small errors, will lead to paralysis of the entire project. The construction of water conservancy projects not only to do a good job in the construction, need to do a good job after the completion of the construction, repair and maintenance work, early discovery, early maintenance, this can not only improve the service life of the project, reduce economic losses due to water conservancy engineering problems, more is a major event in the benefits the country and the people.
Reference
[1] Cai Shujun. Anti leakage technology of water conservancy project [J]. Beijing agriculture, 2013 (09): 223
[2] Huang Yong, Hu Maoping. Discussion on construction technology of chemical grouting technology in water conservancy project [J]. Jiangxi building materials, 2012