Inland river shipping has achieved its own leap-forward development with the advantages of less land occupation, low energy consumption, large traffic volume and less pollution. The construction of high-grade inland waterway in China has begun to take shape, which has laid the foundation for the sustainable development of inland waterway construction. Waterway engineering construction has many similarities and differences with other engineering projects. The following is an analysis of some common situations in inland waterway design based on daily experience: the characteristics of waterway engineering: (1) Design and construction are relatively professional, and large-scale port projects are generally expensive due to the influence of natural environment. Most of the projects are carried out on water, with strong mechanical cooperation and high engineering technical requirements. Especially in the foundation construction stage, the construction is more difficult, and the construction is mainly affected by the natural environment, such as channel water level, rainfall, tidal flood and so on. Operation in dry season has become the primary consideration of construction arrangement.
(2) The construction intensity of regional water transport projects fluctuates greatly, and inland water transport projects are mostly invested by the state and enterprises. In recent years, the state has invested heavily in inland waterway construction, but the local waterway construction projects based on rivers are bound to be linear when implementing the relevant national planning and construction, and many of them are concentrated in a period of time. The commencement of some large-scale projects is the climax of water transport engineering construction in this region. However, with the end of large-scale projects, the number of water transport engineering construction projects is obviously reduced, and social investment cannot smoothly enter the water transport market for various reasons, which will inevitably lead to the imbalance of business volume of corresponding design and construction enterprises, leading to the lack of coping ability of enterprises in the high and low tide period of construction, which will have many negative effects.
1 Problems in inland waterway engineering design
1. 1 Inadequate supervision of inland waterway engineering design market.
During the "Eleventh Five-Year Plan" to "Twelfth Five-Year Plan" period, the water transport engineering design industry developed rapidly and the supply and demand were unbalanced. Some water transport design enterprises have been unable to meet the design needs of the rapid development of water transport by working overtime, so they have to take the way of grasping the big and letting go of the small. Some small private enterprises designed by other industries filled the design gap at that time by entering the water transport design market. In the later period of "Twelfth Five-Year Plan", the country carried out capacity adjustment, and the water transport design market entered a low tide period, and the design rate also dropped significantly. Due to the insufficient supervision of the water transport engineering design market, some enterprises have seized some markets, and the water transport design industry has entered a difficult period, resulting in a hungry situation. The phenomenon of unreasonable low price has appeared in the design market. Some small and medium-sized water transport engineering design projects with little difficulty, uncomplicated technology and low use requirements adopt the lowest price method to select design enterprises.
1.2 facilities planning can't keep up with the development speed of water transportation.
Due to the long period of water transport engineering planning and port facilities construction, it can't keep up with the development speed of shipping, which leads to the backwardness of port facilities as soon as they are built. The realistic contradiction between ship enlargement and channel grade mismatch is increasingly prominent and sharp, and a large number of super ships enter inland waterway, which makes the safety risk worrying. Shaying River waterway in Anhui Province is 206 kilometers long, the planned waterway grade is grade 4, and the design representative ship type is 500 tons. Take 1039 ships entering and leaving Fuyang lock for statistical analysis, including barge 162 and cargo ship 877. Statistics show that there are 56 ships with 1500 tons or more, accounting for 5.4%; 100 1 ~ 1500 tons has 283 ships, accounting for 27.2%; 80 1 ~ 1000 tons has 185 ships, accounting for17.8%; There are 360 ships with 50 1 ~ 800 tons, accounting for 34.7%; There are 185 ships with 30 1 ~ 500 tons, accounting for14.7%; There are 2 ships under 300 tons, accounting for 0.2%; Ships under 500 tons will be eliminated.
1.3 The determination accuracy of design parameters of waterway engineering is not high and complete, so it needs to be verified.
A theoretically perfect design must be verified by construction before it can become a high-quality project. The natural environment of inland ports in China is very different. With the development of water transport, there are fewer and fewer high-quality shoreline resources, and some bad geological coastlines are gradually utilized, which brings new challenges to the design of water transport projects. The theory and norms of water transport specialty lag behind the design and construction of water transport specialty. To develop the water transport industry, we must take the road of innovation. In the design of waterway engineering, some new technologies, new materials and new processes are constantly adopted, and the road of "specialization and differentiation" is taken to continuously enhance the competitiveness of the industry. Water transport design and construction is the executor and pioneer of water transport professional norms. Through continuous exploration and verification, the existing specifications are supplemented and improved, and the problems that should be paid attention to in determining the design parameters of water transport projects are as follows: (1) Some related indexes and parameters in the specifications have a large range of values, so it is difficult to use them accurately, such as the calculation of ship lock throughput and port throughput, which is somewhat different from the actual situation after operation. (2) When new technologies, new materials and new processes are adopted in the design of water transport projects, there are no relevant parameters in the specifications, which need to be verified by construction tests, and it is easy to cause cost omissions or deficiencies.
(3) Setting out the design coordinates and elevation of waterway engineering is easy to make mistakes, especially in the second phase of construction. Generally, when designing the second-phase project, the coordinates are directly read from the surveying and mapping of the first-phase project, but in the construction process, the construction unit needs to reset the control points within the scope of the second-phase project for lofting, so that there will be some deviations in the coordinates of the structures of the first and second-phase projects, such as dislocation along the line and different elevations of the wharf surface. (4) The design and construction water level of waterway engineering is the key factor to determine the construction scheme and structural foundation, which is often not paid enough attention: the construction water level is determined according to the construction time of the engineering foundation, and the dry season is generally selected, so the construction water level is set high, and the structural stress is poor, which increases the investment; The construction water level is set low, so it is impossible to carry out construction. Relevant measures need to be taken to change the project and the investment will increase. (5) There are often some problems in the use of geological and stratigraphic indicators of water transport engineering. Geological and stratigraphic indicators have always been the basis of waterway engineering design. Determining the foundation form of the structure according to the geological conditions, especially the bearing capacity of the pile foundation, will be inconsistent with the design. At present, geological exploration still reflects the stratigraphic distribution in a certain range from point to area. For the sake of safety, the stratum indexes generally provided are conservative.
2. Countermeasures and suggestions to improve the design level of inland waterway engineering
2. 1 full competition, the industry needs self-discipline.
The main purpose of bidding for water transport projects is to achieve full competition in the water transport design market and seek reasonable quotations. It is another important task of bidding to prevent the problem of clean government in the process of contracting water transport projects and put an end to various forms of kickbacks and other benefits.
2.2 Study carefully and reserve room for development.
Design should be based on the actual situation, careful investigation, in line with the planning premise, there should be appropriate development space. 20 13, the preliminary work of Yingshang double-track ship lock began. According to the current situation of ship navigation and the specific channel conditions, it is determined that the design representative ship type of the double-line lock is a 500-ton ship 1000-ton ship. The effective scale of the ship lock is increased to 200×23×4m, which leaves room for the improvement of the channel grade in the future. At present, the large-scale development of inland ships puts forward higher requirements for the design of inland waterway engineering, and also brings unprecedented pressure to the on-site supervision of local maritime departments. How to resolve the contradiction between the present situation of "large ships entering the river" and the practical guarantee of navigation safety, besides properly improving the design standard of waterway engineering, strengthening the construction and maintenance of infrastructure, ensuring that the hardware conditions are in good technical condition, improving the anti-collision ability of waterway engineering itself, and perfecting safety warning signs, it is more important to strengthen on-site supervision, strictly limit the disorderly development of large ships, promote the standardization of inland river ships, and develop smooth, efficient, safe and green inland river shipping.
2.3 Moderate adjustment, in line with the actual situation.
(1) In order to solve the problem that some related indexes and parameters in the specification vary widely and are difficult to use accurately, corresponding adjustments should be made according to the actual situation in the future design, so as to conform to the actual situation as much as possible and bring into play economic benefits. (2) The time limit for a project and emergency measures of new technologies, new materials and new processes should be considered in the design, and the cost of related measures should also be considered. Design disclosure before construction and post-service during construction are the quality assurance of waterway engineering. Design, construction, supervision and owners should communicate in time to form a unified opinion, so as to make the project go on normally and avoid wrangling in the later stage. (3) The problem of coordinate and lofting is that the measurement itself will produce errors. The solution is to require the construction unit to postpone the design based on the structure of the first phase project. (4) In recent years, the water conservancy department has carried out comprehensive management of rivers and lakes, and the flood control capacity has been greatly improved. In addition, water resources are becoming increasingly tense, and hydrological conditions change greatly in dry season. In some water conservancy projects, the traditional dry season has become a wet season, and the actual dry season has become a pre-flood season. It is necessary to conduct on-site investigation and reasonably determine the construction water level. For example, in 2006, the Linhuaigang Hub of Zhoujigang Phase I did not store water, the construction water level was 19m, and the pier used bored pile foundation; In 20 12, the linhuaigang hub of Zhoujigang Phase II began to store water, and the construction water level was 21m. PHC is used to drive piers into pile foundations. The construction water level has great influence on the structure and construction technology, which needs to be paid attention to.
(5) In order to make the design of pile foundation reasonable and avoid loss, the code requires that the pile should be tested before construction, and the pile length and geological and stratigraphic indicators should be adjusted appropriately according to the test results. For example, the pier project of a shipyard near the Yangtze River in Wuhu must be designed according to the requirements of complex stratum conditions. The owner, supervisor, construction unit, design unit and geological prospecting unit were all on site during the pile test, and as a result, the three test piles failed to reach the design elevation. According to the pile sinking situation, the geological prospecting unit adjusted the stratum index, and finally determined that all the pile lengths of the wharf were shortened by 3 meters. However, we should also pay attention to other situations, such as the foundation construction of a pier approach bridge in Chizhou Yangtze River. The bent frame of the approach bridge is two φ 1000 bored piles and 10m weathered rock, and the construction is normal. However, the frame piers of the approach bridge are four φ800 bored piles, which cannot be driven after entering the weathered rock for 6m, so the design needs to be changed. After the designers and geological prospectors arrive at the site, they should first fish out the hole slag and make a careful judgment. It is found that the drill bit should be able to drill down when entering moderately weathered sandstone. After analyzing the reasons, it is found that the mud is too thick, the φ800 bit is lighter than φ 1000 bit, the stroke is not increased, and the φ800 bit is seriously worn. Treatment method: appropriately reduce the mud proportion, appropriately increase the bit stroke, and replace the new bit, and finally successfully complete the foundation construction.
3 Conclusion
The design of inland waterway engineering has great influence on national and local economic construction, and it is an important work involving a wide range. It is also of great significance to seriously face all kinds of problems in inland waterway design, deeply analyze their causes and try to solve them from the root. It is also of great significance to further correct the competition among water transport engineering design enterprises, promote the effective implementation of relevant national laws and regulations, and further improve the legal level of the whole society and the technical level of design enterprises. I believe that with the joint efforts of all parties, the inland waterway design industry will certainly develop healthily.
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