In order to fully implement the national, provincial and municipal requirements on the construction of sponge city and effectively promote the construction of sponge city in Foshan City, Guangdong Province, according to the relevant documents of sponge city issued by the state, province and relevant ministries and commissions, Foshan City made overall arrangements for Foshan City to compile and improve the technical standards of sponge city in the Implementation Plan for Promoting the Construction of Sponge City in Foshan City. The compilation covers four separate technical guidelines for building and residential projects, water projects, transportation infrastructure projects and green space and park projects. As one of them, Foshan Sponge City Traffic Infrastructure Construction Technical Guidelines (hereinafter referred to as Guidelines) will be used to guide the planning, design, construction, maintenance management, performance evaluation and approval management of Foshan traffic infrastructure projects.
1 Main contents of the Guidelines
The guide stipulates the planning and design objectives, planning guidelines, design points, construction supervision requirements, maintenance management points, performance evaluation methods, examination and approval management methods of Foshan traffic infrastructure projects.
2 "Annual Runoff Total Control Rate" Rapid Test Method Research
2. 1 Selection of planning and design objectives
The objectives of sponge city in transportation infrastructure projects generally include total runoff control objectives, peak runoff control objectives and runoff pollution control objectives. Through analysis and comparison, Foshan regards total runoff control as the most important control goal, which is generally characterized by "annual total runoff control rate". Therefore, the planning and design goal of Foshan transportation infrastructure sponge city is characterized by "annual runoff total control rate" The annual total runoff control rate corresponds to the design rainfall one by one, that is, it reaches a certain annual total runoff control rate target, which is used to determine the rainfall control value that does not affect the design scale of development facilities. Based on the statistics of meteorological data in Foshan in recent 30 years, the design rainfall corresponding to the annual runoff control rate in Foshan is obtained (see table 1 and figure 1). According to Foshan Sponge City Guidelines, the annual runoff control rate in Foshan is 70%. Based on the analysis of the current situation and the planned municipal road section size in Foshan, the nine most widely used section sizes in Foshan are sorted out to determine different total runoff for new or rebuilt projects.
2.2 put forward a quick inspection method
At present, the accessibility of the transportation infrastructure sponge city target is generally verified by hydraulic model or volume method, but both of these verification methods need a lot of basic data and need to be calculated by professional software, while the general planning and design units and government functional departments do not fully grasp these local data and skillfully use professional software. It is impossible to determine whether the design and acceptance confirmation of the next stage of the project meet the specified annual total runoff control rate. Therefore, considering the lack of relevant basic data, this guide proposes for the first time that the municipal roads in Foshan (including roads with the function of municipal roads) can quickly obtain the evaluation value of the annual total runoff control rate of various municipal roads according to the actual construction situation of the project, and the design unit and management department can compare it with the corresponding Foshan city through the process shown in Figure 2. After review, the management department thinks that the target can be achieved before the next stage of construction is allowed. Otherwise, opinions should be issued to require the design unit to modify the design scheme until the sponge goal is achieved.
2.3 the establishment of rapid inspection method
The establishment of quick search method needs to unify relevant design parameters to ensure the consistency of later data. When using the quick look-up table in the future, the relevant design parameters should meet the requirements in Tables 3 ~ 4. 1) Analyze the influence of road length, total road width, green space width, sidewalk width, carriageway width, sidewalk water permeability, depression depth and other factors on road rainwater runoff control rate under different parameters. 2) Collect the typical section of Foshan about 138, analyze the factors such as road width, pavement width and green belt width, and divide the original section of 138 into 88 sections.
3) Establishing hydrological model for analysis: Using EPA-SWMM, 88 kinds of sections were simulated according to the total width of roads and the proportion of passenger flow and water received by green space, and 176 kinds of simulation analysis were carried out. Fig. 3 is a cross-sectional view of a road with a width of11~130m. ① Green space for accepting passengers' water: refers to the green space adjacent to motor vehicle lanes and auxiliary roads within the red line, which can accept rainwater runoff from thawing lanes and auxiliary roads; ② Controlled motor vehicle lanes: refer to motor vehicle lanes and auxiliary lanes where rainwater runoff can enter adjacent green spaces for control; (3) The rate of water green space for visitors: refers to the ratio of the water green space for visitors to the area of the corresponding controlled motor vehicle lanes. Figure 3 1 10 ~ 130m wide section Figure 4) Regression analysis: The results of 176 kinds of simulation analysis are analyzed, and the functional relationship between design parameters and annual runoff control rate is regressed. By comparing the correlation coefficient (R2), the regression equation with the greatest correlation is determined. 5) Through analysis and comparison, it is found that there is a high logarithmic regression correlation between the annual total runoff control rate and the proportion of water received by green space, and R2 is between 0.8574 and 0.9963 (as shown in Table 5). 6) Calculate the annual total runoff control rate of the above nine sections when they receive passenger flow water and the green space sinks by 65,438+00 cm and 65,438+05 cm under different green space rates. Figure 3 and Table 6 list the calculation results in the case of 1 1 ~ 130m section.
3 Conclusion
Through the quick look-up table of the annual total runoff control rate of road engineering, the designers of Foshan traffic management department and planning and design unit can quickly and effectively inquire whether the road design and acceptance meet the planning and design objectives of Foshan's transportation infrastructure sponge city, which increases the operability and simplicity of sponge city evaluation, improves the efficiency of sponge city planning and design, and provides a new research method for sponge city construction.
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