Article 1
Discussion on water conservancy engineering design
Design is a very important part of water conservancy project, but the development of the times puts forward high requirements for water conservancy project design. How to combine these requirements and do a good job in architectural design of water conservancy and hydropower projects is worth our deep thinking. This paper mainly expounds the present situation and prospect of water conservancy design with water conservancy engineering design as an important content.
Keyword design; There is a problem; Governance;
1. Introduction
In the construction of water conservancy and hydropower projects, design departments at all levels undertake a series of design work such as project planning, feasibility study, preliminary design and construction design. This paper analyzes the present situation of water conservancy and hydropower engineering design and the common problems in design. Some countermeasures and suggestions are put forward from the aspects of improving the responsibility, professional quality and strengthening supervision of designers.
2. Current water conservancy project design
1 The construction organization design is too simple.
Whether the organization design of water conservancy project is detailed and comprehensive directly affects the development and implementation of the next work of water conservancy project. However, most water conservancy projects are only very simple in organizational design, such as external traffic, construction diversion, earth-moving distance, river closure scheme, source of building materials, water and electricity supply, construction site environment and so on. , which has brought many problems to the bidding work of water conservancy projects, and the claims of construction parties have become frequent.
2 Waste of water resources
Agriculture is a big water user in China, and the utilization rate of water resources is only about 40%, while the utilization coefficient of irrigation water in China is only about 0.45. If the utilization rate of irrigation water is increased by 10%, water can be saved by 410.90 billion m3 per year, which is equivalent to the total water regulation of the east and middle routes of South-to-North Water Transfer Project. China's second largest water industry is industry. Smelting 1t iron consumes 70~ 100m3 of water, and the reuse rate of water is 70% ~80%, while it is 7~8m3 and 97% abroad in 1990s. At present, citizens in China are not aware of water conservation, and the long-term implementation of welfare water supply makes the water price low. People don't understand the preciousness of water, and the amount of water flowing out of the tap that is not closed is quite amazing.
3 Sewage worsens water quality
The water resources in China are being polluted by agricultural, industrial and domestic garbage, and the water quality is seriously deteriorating. A large number of untreated or incompletely treated industrial and domestic sewage directly flows into river sections and rivers, seriously polluting water bodies. According to the data of the relevant departments of the Environmental Protection Bureau, nearly14 of the river sections and rivers in China have been seriously polluted, which can not reach the level of irrigation water. Rural pollutants have a large output, wide distribution and many kinds, but the relevant treatment has just been put on the agenda, and there are no effective measures and obvious actions at present. According to experts, the total discharge of pollutants is reduced by 2/3 to meet the environmental capacity. However, in all the sewage treatment plants that have been built, due to imperfect planning, the construction of water pipe network does not match the sewage treatment plants, and there are problems to varying degrees.
4 there is a bad behavior of "cutting corners" in the design.
The deepening of water conservancy project design not only means the gradual decomposition and refinement of project cost, engineering quantity and structure diagram, but also includes the improvement and supplement of design basic data and the deeper demonstration of water conservancy project design scheme. The actual design fee has included the cost of supplementary links. The actual situation in engineering project design is that the next design link directly uses the basic materials of the previous link, but there is no specific supplement and improvement work, and the design scheme is not demonstrated in depth, just applying the conclusions and achievements of the previous link.
5 design agencies lack the awareness of serving the owners
Due to the continuous innovation of China's investment system, the owners are responsible for the construction and development of water conservancy projects. The owners of water conservancy projects are responsible for financing, repayment, planning, capital appreciation, capital preservation and management of water conservancy projects, and will inevitably pay great attention to the investment benefit and cost control of water conservancy projects. However, the current design agencies do not have a deep understanding of the mood of the owners, nor can they understand many requirements put forward by the owners. Whenever there is disagreement with the owner in the opinion of water conservancy project, the design agency will perfunctory the owner with excuses such as superior documents and specifications.
6 investment budgeting is not accurate enough
The investment budget of water conservancy project is not accurate enough, which is manifested in: the unit price analysis is incorrect, and the unit price is not accurately analyzed according to the specific price standard set in the design scheme. In order to save time, some engineering designs usually use the unit price analysis table of previous projects instead of making reasonable adjustments according to the actual material prices, which leads to the unit price of these projects being too high or too low, and ultimately has a negative impact on the whole water conservancy project; The detailed description of the preparation of the budget estimate is too simple, and the annexes and schedules are incomplete; When calculating the independent cost, the old standard is adopted, which leads to the low or high engineering design cost.
3. Development trend of water conservancy project design in China.
The present situation of water conservancy project design in China shows that the current water conservancy project design restricts the progress and reform of water conservancy system to a great extent and hinders the smooth development of water conservancy project design in China. Therefore, the future design of water conservancy projects in China may have the following development trends.
1 design institute contracts to design roads.
Through the concrete practice analysis of water conservancy project design contracted by design institute, it is found that water conservancy project design contracted by design institute can effectively integrate various resources of water conservancy project and has very obvious development advantages. These advantages include:
1 can save a lot of construction funds.
General contracting of water conservancy projects by design institutes can make engineering designers pay more attention to the investment of water conservancy projects and design the best water conservancy project design scheme, which can not only simplify the flow of various media and promote the economic and efficient implementation of the project, but also make the material flow direction, process layout and process flow more reasonable, realize the consumption reduction and energy saving of water conservancy project construction, and finally achieve the purpose of saving investment and reducing project cost;
2 can promote the construction department, the procurement department and the design department to be closely integrated.
Engineers of construction, procurement and design can fully communicate with each other in technology and information, so as to avoid the undesirable phenomenon that construction, procurement and design are fragmented, which can effectively prevent construction mistakes and procurement mistakes caused by not understanding the design intent;
○3 can effectively improve the management level of water conservancy projects.
The design institute can effectively grasp the progress of the whole process of water conservancy project, and finally strictly control the quality, cost and progress at the target value through scientific analysis and management;
○4 can accelerate the pace of innovation and reform.
Designers directly participate in the whole process of procurement, commissioning and construction, and keep close contact with relevant markets, so as to directly apply the lessons and problems generated to the design improvement of water conservancy projects. In addition, engineers can deepen their practical work and improve the design level of the project, which can generate more power for technological innovation.
2. Seriously carry out work safety in production.
Give priority to prevention, strengthen supervision, implement responsibilities, and continue to carry out the "year of safe production" activities; Establish and improve the safety production supervision and management institutions, equip full-time safety production supervision and management personnel, and implement the safety production responsibilities at all levels; Earnestly do a good job in safety production inspection, rectification of hidden dangers of accidents and monitoring of dangerous sources, go deep into the reservoir construction site to carry out safety inspections before and during the flood season, effectively prevent and resolutely curb serious water conservancy production safety accidents; Organize publicity, education and training on production safety, further enhance safety awareness and further improve the ability and level of supervision and management.
3 further solve the quality problem of designers
In the next few years, China's relevant departments will pay more attention to the adjustment of talent structure, strengthen talent training, rationally use talents, gradually improve the employment environment, establish strict and effective restraint and incentive systems in the flow of production factors, personnel and labor management, production organization and other aspects, fully mobilize the initiative and enthusiasm of engineering designers, and improve the treatment of designers.
4. Strengthen and improve the legal system construction and review.
In recent years, great changes have taken place in the management and production of water conservancy engineering design enterprises in China, which are gradually changing from integration and specialization to professional management as the basis and project management as the core, and the management modes of various engineering projects will also change. At present, the concrete standards of water conservancy construction in China are basically a standard system that organically combines recommended standards and mandatory standards, and there are a series of problems such as inadequate implementation of standards, complicated contents and insufficient supervision. In the future, the evaluation and design experts of China's water conservancy authorities must make full use of the law to regulate the market and make a comprehensive review. In the review process, it is necessary to go to the field frequently to learn more details, and formulate corresponding regulations, guidelines and requirements to implement the corresponding requirements in the review design stage.
Will cultivate more comprehensive talents.
In order to vigorously promote the smooth progress of water conservancy project design, China will establish a file of outstanding talents in water conservancy project construction in the future, and plan to train engineers in project management, computer application, knowledge structure, project evaluation and engineering construction experience, and continuously train more and better comprehensive water conservancy project construction talents to promote the development of water conservancy project construction in China.
4. Concluding remarks
Through the description of water conservancy project design in recent years, the main problems existing in water conservancy project design are systematically summarized and analyzed, and the corresponding solutions are put forward, which provides reference for optimizing design of small and medium-sized water conservancy projects, improving design quality and improving overall design level.
refer to
[1] Liu Houhu. Problems and improvement measures in hydraulic engineering design [J]. China High-tech Enterprise, 20 109.
the second
Analysis of dike engineering design
Abstract: Dike is the earliest important flood control project widely used in the world. Dike construction is the main measure for flood control, protection of residents and industrial and agricultural production. However, some problems are easy to appear in dike engineering design. This paper briefly analyzes the problems that are easy to occur in dike engineering design, and puts forward design suggestions.
Keywords: analysis of dike engineering design problems
In the past two years, the national small and medium-sized river regulation project has been actively promoted. In the process of project evaluation, it is found that there are some key problems in dike design that affect the safety and investment of dike engineering. There is a certain distance between the proposed governance plan and the governance goal, which leads to repeated revisions of the design report. According to the project review, the main problems are briefly summarized and analyzed, and some preliminary suggestions are put forward for design reference.
First, reasonably determine flood control standards and dike grades.
Flood control standards for dikes should take into account the flood control characteristics of river reach and the needs of economic and social development of protected areas, and make overall consideration of the flood control impact of this river regulation on large rivers, and coordinate with flood control standards for river basins, upstream and downstream and other shoreline. It is not appropriate to raise or lower the flood control standard of regional dikes. In some places, the protection object of this dike section is emphasized unilaterally, and the flood control standard and dike grade of the regulation section are improved. Levee grades should be adapted to flood control standards, determined in principle according to flood control standards and approved flood control plans, and coordinated with the projects and levees approved by the upstream, downstream and left and right banks. In the design of some dike projects, the levees with flood control standard of 100 and once every 50 years are classified as Grade 2 and Grade 3 respectively, which do not meet the requirements of current codes, resulting in that the crest elevation, dike section, compaction standard and stability safety factor cannot meet the requirements of flood control standards. For dikes whose reservoir combination meets the flood control standards of protected objects, their grades should be determined by the flood control standards of protected objects, not by the flood control standards of dikes. In this case, the flood control standard of dike is generally lower than the protected object.
Two, the construction content and design scheme should meet the requirements of flood control project management.
The construction content and design scheme should focus on flood control projects, taking into account the needs of urban landscape and local development, and should not put the cart before the horse, resulting in increased investment. For example, from the perspective of flood control, some river sections can directly adopt high bank or bank slope protection as the design scheme. However, considering the needs of urban planning and construction, the design unit adopted a retaining wall scheme with a height of more than ten meters, and in order to meet the requirements of foundation bearing capacity, it is necessary to add concrete mixing pile foundation treatment measures under the retaining wall. Some people say that the increased investment does not need state investment, but only needs to review and approve the plan.
But in addition to the management of highways, bridges, municipal and other industries, there is also a hidden danger of flood control. The design scheme of high bank or bank slope protection is adopted, and the flood control measures are simple and clear, safe and reliable. However, the construction of flood control wall with a height of more than ten meters on the bank slope increases the depth of geological exploration work of dike engineering, and the engineering design is complex, and a slight negligence may cause potential safety hazards. Flood control wall scheme is the need of municipal construction, not the necessity of flood control project, and does not meet the requirements of flood control project management. If the flood control scheme has the same demand as municipal construction, its control measures and section design can take into account the needs of urban construction and local development, and the increase of flood control project investment should be solved by corresponding municipal and other channels.
3. Reasonable selection of dike line layout scheme
In the design stage of dike project feasibility study, the selection and layout of dike line is very important, but many design units often pay insufficient attention to it. Besides the deficiency of the report itself, the comparison and selection of schemes
If it is not in place, the dike line scheme mainly exists in cutting and bending straight and channelized rivers at will; Reduce the flood discharge section by using the beach; The revetment line is confused with the dike line.
In principle, the layout of 1 dike line should not be curved, but should be curved along the river to maintain the natural shape of the river. River regime is the result of natural evolution for thousands of years, and it is independent of human will.
Man-made bending and straightening need greater engineering protection measures, which do not meet the requirements of ecological environment. Vice Minister Jiao Yong clearly pointed out in his speech at the national conference on the management of small and medium-sized rivers that river management "is strictly forbidden to cut corners and take a straight road, and should be coordinated with the surrounding environment and ecological landscape". In some projects, one-sided emphasis on layout along the control line is not advisable. Some river embankments have been gradually raised and thickened in history, and they are not straight in themselves. On the premise that the existing dike line is basically reasonable, there is no need to change the layout of the existing dike along the control line. The control line is only a theoretical line, and the layout of the dike line should be determined in combination with the existing dike line, topographic and geological conditions, flood control protection objects, resettlement land occupation and other factors, and the layout pattern of the dike line can meet the requirements of the control line.
2. The dike line layout should be basically arranged along the existing dike line or coastline, and the narrow section of the riverbed should retreat to the beach as far as possible, so as not to encroach on the flood crossing section. At present, there is no dike section, and the dike line should be selected after scheme comparison according to the topographic conditions and the dike distance determined by hydrological planning. When there are natural highlands, the natural highlands should be used as embankment lines as much as possible, and the stability and anti-scouring ability of natural slopes should be checked during design, and protective measures should be taken when necessary.
It is not allowed to change the line or build a new dike line through scientific argumentation, occupy the beach to narrow the flood discharge section or bring unnecessary protected objects into the scope of protection. Some embankment sections are dikes.
Basically meet the requirements of flood control, but due to various reasons such as housing occupation, moving the dike line to the beach and building new dikes for protection not only increased investment, but also increased the upstream flood control pressure. In some projects, in order to bring the houses and cultivated land within the beach or the planned dike distance into the scope of protection, the dike line or the planned dike distance is changed to narrow the river course. The dike line layout should be based on the whole project, and regional interests should not affect the whole dike line layout or increase flood control pressure.
4 revetment line and dike line are confused.
Under normal circumstances, rivers often flood from the main channel during floods, and the floodplain overflows during major floods. In some projects, the dike line is moved to the front of the beach, and all the design standard floods are discharged from the main channel, and the beach is changed from flood discharge area to flood control area, which leads to a significant increase in the cross-section type and structural size of the dike body, which not only increases the investment, but also increases the flood control pressure and risk. Especially in mountainous rivers, revetment should be given priority to in front of the beach, and embankment should not be built.
Fourth, reasonably determine the embankment section.
The unreasonable embankment reinforcement method may destroy the existing embankment section and surface protection measures, which is not convenient for construction. Generally speaking, embankment should be reinforced on one side as far as possible, avoiding both sides.
Side training. The method of adding soil is comprehensively determined by considering the current embankment section, the nature of adding soil, the distribution of material yard, the land occupied by immigrants and other factors. For embankment sections below 30 ~ 50 cm in height, no additional culture is needed.
It can be combined with the comprehensive consideration of embankment top pavement construction to meet the flood control requirements. The cross section of embankment should be suitable for filling materials. In principle, the nearest materials should be used for filling materials, and the transportation distance should not be too far, and the mixture should not be used. By designing a reasonable section of the dike body, the defects of building materials are made up. Due to the lack of protective measures, the surface of sand dikes is often destroyed or burst by floods. Therefore, it is necessary to set clay on the water-facing side of the sand dike or combine with slope protection measures for surface protection.
Five, targeted selection of slope protection and revetment measures
Slope protection and revetment engineering measures account for a large proportion in dike engineering investment. Reasonable slope protection and revetment engineering measures not only ensure the safety of the project, but also make the project investment reasonable and minimize the damage to the ecological environment. The main problems that often appear in the design report are: 1 unreasonable slope protection range, and some projects also use hard slope protection in the non-scouring parts of Shunzhi reach; 2. Too much hard slope protection and revetment, and insufficient ecological environment; 3. Too much emphasis on ecological measures, and measures such as counter-current flushing and counter-current leaning are slightly unsafe; 4 copy, not suitable for local building materials; 5. Insufficient attention has been paid to the depth of scour protection and foot protection measures.
Six, according to the dam seepage stability analysis, reasonable choice of seepage control measures.
The seepage stability analysis should be targeted, and the selection of typical sections should correspond to the embankment foundation and embankment body packing. Seepage analysis should be based on embankment foundation layer and embankment fill, and calculated according to Appendix E of GB 50286-98 "Code for Embankment Design". It should be noted that the general riverbanks may not form stable seepage, but the riverbanks of large rivers and lakes or important riverbanks of small rivers and lakes should be calculated as stable seepage.
In the case of increasingly scarce land resources, the choice of anti-seepage measures should follow the principle of minimizing land occupation. For example, the surface cohesive soil layer of more than 30 kilometers of double dike foundation in a province is thin, which can not meet the anti-floating stability requirements of the surface cohesive soil after preliminary accounting. The cohesive soil behind the dike is compacted, with a width of about 10m and a thickness of only 1.5~0.5m ~ 0.5m, occupying a lot of land. In fact, the anti-floating stability of the surface clay of this double-layer dike foundation has little influence on the safety of the dike body, mainly because of the seepage stability of the lower sand layer. The design should check the permeability stability of sand layer. If it does not meet the requirements of seepage stability, it is necessary to add filtration and drainage protection measures in a certain range behind the dike. Another example: a sandy embankment foundation, laying crack-stopping geomembrane under the slope protection of the embankment body, not only can not play the role of seepage control of the embankment foundation, but also will bring hidden dangers to the stability of the slope protection due to reverse water pressure.
To solve the problems of seepage stability, it is necessary to comprehensively analyze and compare the factors such as embankment foundation layer, embankment fill, resettlement land occupation and project investment. Choose technically feasible, economical and reasonable anti-seepage measures.