0 preface language.
Domestic small reservoirs have a considerable part of the building's long, when the level of construction technology, the quality of materials, the latter part of the maintenance level of subjective and objective factors, in after a long time of operation will inevitably be some impact on the performance of the. If laissez faire on these issues, is bound to caused a serious threat to the downstream regions of the people's life and property safety, therefore, must be through all kinds of danger and reinforcement technology of problem to solve, for the reservoir using efficiency into full play and safe operation provides more security [1]. Due to the small reservoir reinforcement technology more, so in the process of selection and the practical application of must guarantee the construction scheme of pertinence, the danger and reinforcement engineering more feasible and reliable. Below, common defects of small reservoirs were simple instructions, and around the earth rock dam reinforcement application and main points of construction technology are discussed.
1 common diseases of small reservoirs.
Mainly includes 2 aspects of the content:
1.1 dam seepage.
Domestic small reservoirs in quite a number of construction in the 20th century, from the 1950s to the 1970s, construction technology and management level of the time constraints, some reservoir in the process of building didn't even formal planning and design, construction scheme is the product of "crossing the river by feeling the stones". Under the influence of these factors, the dam seepage is the most common. In general, the dam seepage problem is caused by long-term erosion of the reservoir, if not on such issues in a timely and effective solution, it is easy to cause the serious consequences of dam collapse.
1.2 dam structure diseases.
Dam structure disease is often caused disrepair, appear this kind of problem, dam stability, structural strength, stiffness, flood control function will substantially reduced, thereby causing cracks, landslide, drainage, such as profit Hong and other common earth rock dam. If there is no adequate attention to these issues or failure to timely and effective exclusion, often cause serious consequences.
With the continuous development of China's water conservancy, reinforcement technology level continuously improve, small reservoirs exist in the process of operation of various problems can get timely find and solve, effective way to avoid the large-scale emergence of reservoir disease and for downstream regions of the people's production and living order, safety of life and property provides effective protection.
Application of 2 small reservoir reinforcement technology.
In small reservoir reinforcement engineering, the reinforcement technology is mainly used in seepage control of earth rock dam, landslide treatment, crack treatment 3 is the most common disease of earth rock dams link and its application are as follows:
2.1 seepage control of earth rock dam.
In the small reservoir reinforcement project, anti-seepage in earth rock dam is a complex. First of all, it is the construction of concrete cutoff wall, concrete cutoff wall with the reinforcement of earth rock dam, the dam seepage prevention ability and the ability to resist shear. In the construction process of the cutoff wall, the technical personnel should focus on the analysis of the stress, which is very important in the construction of the deep dam seepage prevention wall. Because the impervious wall of dam foundation will be affected by the impact of water impact force and the weight of the dam, the dam itself is prone to deformation and thus cause seepage problems. Therefore the anti-seepage treatment process, the staff should be and guarantee the quality of concrete cutoff wall construction, simultaneously should also pay attention to the completion of high jet grouting impervious wall construction, such cutoff wall is widely used, its technology is relatively mature, construction progress is more than 20 times of the impervious wall in general. But in the actual operation, to ensure the construction technical level to meet the design requirements, otherwise will not be able to fully play the positive role of the reinforcement. Generally speaking, in the use of high jet grouting cutoff wall, the depth and width of the selection should be based on the construction standards, the actual situation of the dam, in order to make the construction of the performance of the finished product more targeted.
2.2 landslide treatment of earth rock dam.
The reason of the landslide of the small reservoir is not reasonable, the filling density is insufficient, the dam foundation has the soft soil layer or the dam slope is too steep. Aiming at the problems of the causes and reinforcement engineering in the bottom bearing capacity increased the dam flood control capacity regulation. Owing to the collapse or mud soil easily induced landslide. Therefore, in the construction process can be in the dam site to build a road riprap solid feet tooth antiskid wall. The tooth wall must be higher than the foundation surface, so as to obtain a better balance of pressure after the backfill effect, in the non slip wall, the platform between the formation of a layer of anti filter layer. In addition, in earth rockfill dam body intact, landslide appears in the upstream of the dam and the existence of local collapse of, in the reservoir water level is reduced to take proper drainage measures of removing loose soil, enhance the permeability of earth dam, the related problems are self repair.
2.3 crack treatment of earth rock dam.
Crack is earth rockfill dam is most common, the most dangerous and serious diseases, in dealing with this kind of problem, reinforcement technology usually adopts the method of backfill excavation. Before the start of construction, technical personnel deal with earth rock dam crack degree were observed, if the crack is small, preliminary excavation depth control in less than 100 cm, if in the excavation process found fracture development by seam poured into fine sandy loam, with sticks to lay a solid foundation. According to previous construction experience, in most cases, the depth of excavation should be controlled within 30 cm, and then backfill and compaction, so that the new and old soil can be successfully mixed and cohesive. In addition to determine crack processing diameter is earth dam cracks treatment work in an important part of, generally speaking, if the crack depth is less than 5 cm and continue to, the stepped open pit and groove digging, in the backfill process will be steps one by one to truncate, keep the trapezoidal cross section, so that the original dam, backfilling soil materials are basically consistent. In general, the depth and width of crack treatment is a key factor in determining reinforcement quality, construction and technical personnel must be of the field survey, in order to obtain the optimal reinforcement effect.
The main points of construction technology of 3 reinforced earth rock dam.
3.1 laying construction.
In the laying of the construction, laying thickness will have obvious influence to the construction effect, so technicians should combined with reservoir, covering layer depth, clay soil material properties such as the actual situation of construction materials for a reasonable choice, for different types of soil used for construction materials. Generally speaking, the thickness of fine sand is small, and the high injection grouting technique can be used in the laying of fine sand, so as to obtain the most ideal reinforcing effect.
3.2 grouting construction.
Grouting construction focuses on the process of reasonable selection, staff before the start of construction should be fully prepared, especially to do the scientific allocation of grouting material, after the end of the grouting and grout sealing work and do a good job, in order to avoid flooding or leaking problem. At the same time, designers to deal with the construction side of technical disclosure, to fully understand the design drawings of the requirements and the original structure of earth rock dam foundation concrete conditions, so as to avoid damage to the original results and reasonably determine the excavation depth and width. In addition, after the grouting construction should be carried out in time to carry out drainage work, a reasonable set of drainage pipeline, to avoid the dam grouting construction due to poor drainage and can not get the reinforcement effect.
3.3 filling construction.
Filling construction quality determines the quality of the dam foundation, therefore, before construction began, designers should work together with the technical personnel to carry out a survey of the actual situation, in order to achieve the optimization of the construction scheme. In order to effectively control the density of the dam, we should pay attention to the reasonable selection of the dam material and carry out the roller compaction test in advance. In addition to control the density of the dam by way of rolling, vibration compaction method is used to complete the filling, on the one hand, the method can avoid damage to the original soil, on the other hand can also play the role of reinforcement and strengthening.
4 knot language.
Small reservoir whether the construction scale and technical difficulty can and large and medium-sized reservoirs mentioned in the same breath, but because of its large number, wide distribution, once appear serious quality problems, still poses a serious threat to the downstream regions of the people's life and property safety. In view of the present situation, domestic small reservoirs reinforcement technology has been towards mature, the introduction of technology standards and norms is for the construction of scientific and reasonable provides a fundamental guarantee, but in practical application process, the staff still need to pay attention to combine the actual situation of construction scheme for a reasonable choice, only in this way can we for the construction quality to provide basic guarantee, enhance reinforcement effect at the same time, the social and economic benefits of the reservoir get maximum play.
Reference
[1] 陈树明.黑龙江省小型水库除险加固[J].水利科技，2012,40（09）：251-252