How are the levels of embankments divided? How are flood protection standards determined?

Embankment roads are road projects that use embankment projects as the roadbed and lay pavement structures according to different combinations of embankments and roads. In the urban flood control section, municipal designers and urban planners also refer to embankment roads as riverside (river) roads. Many sections of mountain roads run parallel to rivers, and one side of the roadbed becomes the bank of the mountain river. This type of road is called a riverside road. , current research focuses on planning and construction issues and development strategies and directions. Lu Zhenjie and others discussed details such as embankment and road combination forms, embankment foundation treatment, and embankment body compaction from the perspective of urban embankment and road combination engineering design; Tian Weiping and others conducted a study on water damage disasters and erosion protection of roads along rivers. Research. The above research has a certain guiding role in the construction of embankment roads, but it does not involve the actual functions of embankment roads in different environments. Because embankment roads simply apply highway or urban road standards in the design, without considering their own characteristics, without reasonable classification and grading, and unable to reflect their own functions and characteristics, there is a certain degree of blindness in the current construction. Based on the development process and functional evolution of embankment roads in my country, and with reference to the engineering status of embankment roads (waterfront roads) that have been built in my country, this article puts forward the idea of ??functional classification of embankment roads, studies the classification basis of embankment roads, and establishes the classification and classification of embankment roads. system.

1. Overview of the development of embankment roads

As flood control facilities, embankment roads can improve traffic conditions on the top of the embankment, making project hazard detection, reporting, and rescue operations quick and timely. Our country has a vast territory, complex natural geographical conditions in various regions, different embankment construction conditions, and great differences in the development of flood control roads. Judging from the construction process of embankment roads in my country, its development and functional evolution have generally gone through the following three stages.

The first stage: single function stage. Since 1949, most of my country's embankments have low standards, poor quality, and insufficient flood control capabilities. The rivers and rivers along the rivers are seriously threatened by floods. The core of embankment construction is mainly on blocking and reinforcing embankments, strengthening embankments, and building up to standard embankments. During this period, flood control vehicles mainly used unpaved earth embankment tops or gutter platforms to pass. Even if the pavement structures on individual embankment tops were paved, low-grade pavements were used, such as mud-crushed gravel pavement, marl-crushed gravel pavement or gravel pavement. . Occasionally, there are important urban flood control sections, and the top of the embankment adopts a simple cement concrete pavement structure. During this period, the embankment road had poor traffic capacity and was easily damaged by various vehicles in rainy days. During this period, the main function of embankment roads was flood control, basically ensuring the normal passage of embankment management vehicles and flood control emergency repair vehicles.

The second stage: the function expansion stage. As embankment construction has received more and more attention, people's traffic requirements for flood control have gradually increased, and the construction of embankment roads in various regions has begun one after another. Since the 1990s, embankment roads in the lower reaches of the Yellow River have been paved with asphalt gravel, which can meet the standards of third-class highways. In addition, some urban waterfront roads have begun to show a multi-functional development trend. These embankment roads have high construction standards, large widths, and complete transportation facilities. Most of them use high-grade pavements such as asphalt concrete or cement concrete. They integrate flood control, transportation, landscape, leisure and other functions within the city.

The third stage: the feature-rich stage. Entering the 21st century, comprehensive river management in various regions has been carried out one after another. As part of river management, the construction of embankments and roads has also accelerated. The standardized embankments in the Shandong and Henan sections of the lower reaches of the Yellow River completed from 2002 to 2008 were built into a standardized embankment system integrating the three functions of "flood control security line, emergency transportation line and ecological landscape line" on both sides of the Yellow River. The construction of embankment roads in the urban flood control section is in full swing. For example, the Yongjiang Embankment Road Park Project in Nanning City, Guangxi Province in 2005, and the Binjiang Road in the main urban area of ??Chongqing City in 2010 pay more attention to the functions of landscape, water, leisure and other functions, and introduce a large number of them. Multifunctional social public services and activities have played a great role in developing the value of land along the route and building commercial outlets.

2. Functional classification of embankment roads

2.1 Significance of functional classification

The functions of embankment roads in the new era are gradually diversified and comprehensive, and the functions of embankment roads should be determined according to local conditions. Each function is of great significance in clarifying the nature of the embankment road, providing basis and guidance for its planning and construction, and enabling the embankment road to be comprehensively utilized.

a. Proper classification of embankment road types. If the expansion function of the embankment road is not fully considered during construction, resulting in low construction indicators, it will not be able to meet long-term needs and face the possibility of reconstruction and reconstruction.

The current classification of embankment road grades is based on the standards of urban roads or highways. However, in terms of main functions, embankment roads are somewhat different from them. Therefore, it is necessary to clarify the multiple functions that embankment roads may have and the different combinations of functions. corresponding grade classification.

b. Reasonably determine the layout of the road width. Determine the priority of embankment road functions, use the limited width to rationally allocate various functional areas, scientifically arrange the size and position of motor vehicle lanes, non-motor vehicle lanes and separation strips, so that all types of vehicles and pedestrians can pass smoothly, and provide solutions to adapt to different conditions. The cross-sectional form of functional requirements can be reasonably selected by decision-makers.

c. Reasonably determine the pavement structure form. The axle load of vehicles driving on embankment roads varies greatly. For example, on embankment roads far away from the urban road network, most of the vehicles driving on embankment roads in the dry season are passenger cars or agricultural vehicles, and the traffic volume is not large; during flood fighting and rescue periods, embankment roads need to Withstand repeated crushing by heavy-duty vehicles and construction machinery. Only by determining the main types and driving characteristics of driving vehicles can we ensure that the road surface can withstand the axle load of the vehicles and ensure its service life.

d. Clarify the ownership of embankment road management. Under normal circumstances, embankment roads as flood control facilities are managed by the water conservancy department, but when they add traffic, landscape and other functions, whether they will continue to be the responsibility of the water conservancy department or be jointly managed and maintained by the water conservancy and transportation or urban construction departments, and how Sharing respective responsibilities and authorities is also something that needs to be considered.

2.2 Functional factors

The main tasks and functions of embankment roads vary depending on their location and environment. The functional positioning of embankment roads mainly depends on the following four elements:

a. The importance of flood prevention tasks. In some cities, the level of embankment engineering in the flood control section is high and the flood control pressure is not great. The transportation demand on embankment roads is increasing day by day. However, many river embankments in my country are still frequently damaged by floods. During the flood season, the National Flood Control and Drought Relief Headquarters and local governments at all levels still attach great importance to flood prevention work. At this time, the main task of embankment roads is still flood prevention and rescue. The primary and secondary functions of embankment roads need to be determined based on the severity of flood control tasks and the population, area and protection objects of the protected area.

b. Management policies. In addition to river authorities, management of embankment roads may also involve transportation and municipal departments, among others. Due to different responsibilities, these functional departments have inconsistent management methods and policies for embankment roads. Different management policies will affect the performance of embankment roads.

c. Objects served by embankment roads. The main service objects of embankment roads mainly for flood control are embankment management vehicles and flood fighting and rescue vehicles, that is, including flood control vehicles and social vehicles; roads that combine embankments, roads, and parks also include tourist vehicles and walking tourists.

d. Planning for the area. As the urban area expands, the built low-standard embankment roads may not be able to provide more services and are not compatible with the surrounding environment. The functions of embankment roads should be combined with local urban and rural planning, and various required functions should be considered in advance based on the development prospects and directions of the areas along the riverbank.

3. Embankment Road Classification System

3.1 Embankment Road Classification Method

Different levels of embankment projects have safety heightening values, anti-sliding stability safety factors, Indicators such as embankment body design are different. The higher the level of the embankment project, the greater the compaction of the embankment body, the wider the width of the embankment top, the better the foundation for building embankment roads, and the higher the road construction standards. High-level embankment projects have heavy flood control tasks. The higher the flood control standards and the higher the level of embankment roads, the more they can meet the needs of flood control and rescue work.

Embankment roads located in rural and suburban areas have few connections with the local road network and are inconvenient for public vehicles to enter. Most of the vehicles passing through are flood control vehicles and embankment management vehicles. The main function of embankment roads is flood control. . Embankment roads located in the suburbs of cities connect many towns and have many intersections, making it easy for vehicles to enter and exit. Social vehicles can use some road sections to pass. If traffic control is not implemented, embankment roads not only undertake flood control tasks, but also have certain transportation functions. Embankment roads that pass through or adjacent to towns and cities pass through densely populated areas with large transportation needs, and inevitably form part of the local road network.

When embankment roads become traffic arteries, their attributes can be regarded as municipal facilities or transportation facilities, and their design and construction should be implemented with reference to the standards of the transportation industry.

The functions of embankment roads, the level of embankment projects and their geographical location are organically combined to form a complete embankment road classification system.

First, analyze the various possible functions based on the importance of the flood control tasks of the embankment road, the expansion of functions and the overall planning of land use in the areas along the line; secondly, analyze the geographical location, connection and status of the embankment road with the local road network, and clarify the priorities. Functional relationship; finally, the embankment roads are classified according to the level of the embankment project and the strength of each function, and a reasonable and complete embankment road classification system is constructed.

3.2 Classification of the nature of embankment roads

The functions of embankment roads can be divided into flood fighting and rescue, embankment management, transportation, social services and supporting facilities. On the premise of ensuring the flood resistance and embankment management functions of embankment roads, in order to make full use of road resources during non-flood seasons, their properties are divided into four categories: flood control, comprehensive, traffic and landscape. For various types of embankment roads, the importance of each function is expressed by the number of ★, where ★★★★★ means very important and ★ means very minor, as shown in Table 1.

a. Flood prevention. Flood control embankment roads are mainly used for flood control and embankment management functions. They are exclusive roads serving rivers and embankments. In any case, the main function of flood control embankments cannot be changed. Only by ensuring the smooth passage of flood control vehicles and personnel can the normal monitoring, repair, maintenance, emergency repair and other activities of embankment projects and the transportation of disaster relief materials be ensured. The priority vehicles served by flood control embankments are all vehicles related to flood control. This kind of embankment road has few connections with local roads. Controlling the only intersections can close traffic and ensure the smooth flow of flood control channels. The traffic volume of flood control embankment roads is often small, the road layout is simple, and they tend to be single-width roads without separation zones. The type and structure of the pavement is mainly based on the needs of flood control vehicles. It is generally required to be simple and practical, and can be repaired quickly when the damage is serious. Flood control roads generally do not have social service and landscape functions, and their greatest feature is their simplicity and practicality. At present, flood control embankments account for the largest proportion of the long embankment lines of rivers and lakes in my country.

b. Comprehensive. When the embankment road is located in the suburbs, with developed agricultural production and some industrial and mining enterprises along the line, it will attract social transportation vehicles. Although the embankment road has a transportation function to a certain extent at this time, its basic functions of flood control and flood control remain unchanged, and it only temporarily plays the role of a transportation road during non-flood seasons. During the flood season, the comprehensive embankment road gives priority to flood control vehicles, and public vehicles are prohibited from entering through traffic restrictions and other measures. During the non-flood season, residents along the embankment have a need to use the embankment road. In addition to embankment management vehicles, social vehicles transporting materials and passengers also drive on the embankment road, so the utilization rate is high.

When different vehicles conflict during transportation, embankment management vehicles have higher priority. Only on the premise of ensuring the flood control and embankment management functions of embankment roads can we consider providing certain transportation services to local people along the coast. A comprehensive embankment road must not only meet the needs of flood control, but also facilitate the passage of coastal residents as much as possible and share the pressure on the road network. Its traffic composition is mainly composed of faster freight vehicles, and there are generally fewer non-motor vehicles and pedestrians. Its road width The layout is mainly focused on the rapid passage of vehicles.

c. Transportation. Rivers pass through or are adjacent to towns. On the premise of ensuring flood control safety, the city's heavy transportation needs are increasing day by day.

The combination of embankments and roads can save land and investment, which is very important for cities and towns. It is the most commonly used construction method for rivers crossing urban embankment roads. In addition, due to the higher embankment body and wider embankment top of the embankment project, it is also possible to build high-standard urban arterial roads. After embankment roads are built, they often become part of the local road transportation network and become riverside (river) transportation arteries, mainly responsible for local transportation tasks. The traffic composition of traffic embankments is overwhelmingly composed of various types of motor vehicles, non-motor vehicles and pedestrians in urban traffic, and its road width layout is also mostly inclined to the layout type of urban roads. The red line has a large width, complete cross-sectional elements and municipal facilities, and caters for various transportation service objects. It is not so much a flood control road as a municipal road, with the performance of both water conservancy facilities and transportation and municipal facilities.

d． Landscape. If the embankment road is located in the suburbs and is not a traffic artery, in addition to meeting the needs of flood control, in order to create an embankment ecological landscape, beautify the urban environment, and develop the coastal economy, the embankment road can be built into a landscape that integrates flood control and leisure entertainment. Avenue. The embankment road built along the embankment has a wide view and beautiful scenery, which can attract citizens to come for sightseeing.

As a landscape road, the landscape and greening requirements are high, and the layout of the road width and the selection of pavement materials are also based on this.

3.3 Classification of embankment roads

The classification of embankment roads is an important basis for determining relevant indicators such as road width and form, as well as pavement material and structure combination. Various types of embankment roads should be divided into 2 or 3 levels according to the level of the embankment project, the corresponding traffic volume and the service functions along the line. At the same time, taking into account flood control safety, embankment roads should not follow the specifications of highways and urban expressways. Construction, the characteristics of embankment roads at each level are shown in Table 2.

a. Level I embankment roads should be based on level 2 or above embankment projects, with necessary separation strips or facility strips to enable continuous traffic flow, 2 to 4 motor vehicle lanes in both directions, or a separate flood control channel, and supporting safety equipment. and traffic management facilities. Motor vehicles and non-motor vehicles should drive in separate lanes, and pedestrian travel needs should be considered in urban sections.

b. Level II embankment roads should be based on level 3 or above embankment projects, with no less than 2 lanes in both directions. The non-motorized lanes should be independent or separated from the motorized lanes, and sidewalks may not be provided.

c. Class III embankment roads should be single-width roads with single or double lanes and no dedicated non-motorized lanes or sidewalks.

3.4 Embankment road classification and grading system

Based on the above-mentioned classification of embankment properties, the nature, grade, location, main functions, etc. of embankment roads are summarized in Table 3 to form an embankment road classification system. Road classification and grading system. All types of embankment roads in Table 3 must meet flood control needs. 4 Conclusion The functional evolution of embankment roads in my country has experienced three stages: single function, function expansion and function enrichment. Functional classification of embankment roads is of great significance for correctly classifying embankment road types, reasonably determining road width layout and pavement structure form, and clarifying administrative ownership.

The factors that influence the function of embankment roads include the importance of flood control tasks, the policies of the management department, the objects served by embankment roads, and the planning of the area where they are located.

According to the importance of embankment roads in performing various functions such as flood prevention and rescue, embankment management, transportation, social services and supporting facilities, embankment roads are divided into flood control, comprehensive, transportation and landscape. 4 categories, and divide each category into 2 or 3 levels. The purpose of establishing a classification and grading system is to provide design basis for embankment roads, formulate reasonable construction standards, and promote flood control projects to meet the needs of modern water conservancy.

Recently, the "Rizhao City Urban Drainage (Rainwater) and Flood Control Comprehensive Plan (2016-2030)" organized and compiled by the Rizhao City Garden Management Bureau passed the expert review.

The review meeting was held in Jinan. The expert group was composed of Shandong Urban and Rural Planning and Design Institute, Shandong Urban Construction Design Institute, Shandong Branch of China Urban Construction Research Institute, Shandong Jianzhu University, Jinan Planning and Design Institute and other units. composed of experts. The experts attending the meeting listened to the introduction of the planning preparation, carefully reviewed and approved the "Plan".

The "Plan" is based on the city's master plan and follows the principles of "overall consideration, systematic coordination, advanced concepts, and economic applicability". Within the scope of the main urban area of ??Rizhao (including Shanhaitian, excluding Lanshan District and Taoluo) Planning and construction within.

The "Plan" determines the urban drainage (rainwater) and waterlogging prevention standards for the main urban area of ??Rizhao City in the next 3-15 years, ensuring that urban river flood control standards occur once in 30 years, flash flood standards occur once in 50 years, and urban moisture prevention standards The standard is once in 100 years, urban waterlogging can effectively cope with heavy rains that occur once in 30 years, and the total rainwater runoff control rate is 75%.

After discussion, the expert group unanimously agreed that the "Plan" has passed the review. It believes that the plan has clear objectives, comprehensive content, and detailed information, and meets the in-depth requirements of relevant national regulations. It also recommends further modification and improvement based on the review opinions.

In the next step, Rizhao City Garden Management Bureau will improve the drainage and waterlogging prevention plan to connect it with Rizhao City’s overall urban planning, road traffic planning, sponge city special planning and other related plans, and fully achieve Make overall plans and make careful arrangements to enhance the guidance and feasibility of planning.