14HYDRAULIC CALCULATIONS OF CULVERTS ON THE HIGH-SPEED SECTION OF THE TASHKENT-SIRDARYA RAILWAY LINE
Elyorbek Begaliyevich Abdualiyev
Tashkent State Transport University, (Tashkent, Uzbekistan).
Auezmurat Bekmuratovich Embergenov
Tashkent State Transport University, (Tashkent, Uzbekistan).
ABSTRACT
This article shows the hydraulic calculation of culverts, which are the most common type of artificial structures in roads and railways. For the passage of water at the intersections of watercourses with the roadbed, culverts are arranged, which, depending on the topographic, hydrological, geological and other conditions, can be of various types.
Keywords: Culverts, bridges, pipes, chutes, duckers, earthwork
INTRODUCTION
The role of Railways in the development of the country's economy, the increase in export potential and the supply of goods to consumers is of great importance. It is not surprising that the railways are called the blood vessels of the country's economy. Therefore, great importance is attached to the development of railway networks and the maintenance of Railways in operation and the maintenance of cargo capacity at the required level[1]. Pipes under the embankment on the railways and make up half of all artificial structures, and these are the most common artificial structures. The scope of application of the pipes is mainly due to the fact that small running water flows from time to time, that is, when it rains and snow melts, ensure that the dressing waters pass without damaging the railway network[2].
MATERIAL AND METHODS
The main regulatory documents in the design of culverts are building codes and regulations. Culverts are designed to pass the maximum estimated costs of a certain probability of exceeding. The probability of exceeding is determined depending on the type of road (railway, automobile), the type of structure (bridge, pipe), the category of road (I, II...V). As a result of hydraulic calculations, the following
parameters should be established that determine the main dimensions of the structures
[3]:
a) the greatest depth in front of the structure, which determines the height of the road embankment;
b) the depth of water at the entrance and in the structure, which determines the mode of flow and filling of the water pipe;
c) the depth of the water and the speed at the exit of the structure, according to which the size and type of fortifications at the exit are assigned;
d) the depth of erosion at the end of the fortifications, the size of which is assigned to the dimensions of the structures of the water-breaking elements. The required hydraulic and structural conditions can be met by different versions of culverts that differ in cost. The optimal construction option should be established by a technical and economic comparison of the options[4].
By hydraulic operation, culverts are classified:
1. According to the conditions of the flow entrance, flat and sloping pipes are distinguished.
2. By the nature of the roughness of the inner surface of the pipe:
- technical, smooth (concrete, reinforced concrete, cast iron, etc.);
- corrugated (metal, plastic, etc.).
3. By the effect of length on throughput:
- short, in which the length does not affect the throughput;
- long, in which the length affects the throughput (Figure 1).
Fig. 1. Flow diagram of water in the pipe: H - head in front of the pipe; hc - flow depth in the compressed section; h0-normal water
depth; hsl - water depth at the beginning of the discharge section; lxx - length of the inlet section;
LT - the length of the pipe; lsi - the length of the drain section; iT - the slope of the pipe; ik-the critical slope[5].
Culverts operate depending on the amount of water intake in front of the pipe in non-pressure mode, semi-pressure mode and in pressure mode. Non-pressure mode of operation is formed if the backstop is less than the height of the pipe at the inlet or exceeds it by no more than 20%. In the non-pressure mode, the free surface above the flow is preserved and calculated by the formula:
qc = vb*uc* * g*(H -hc
Qc - flow rate of water passing through the structure;
®c - the area of the compressed section in the pipe, calculated at hc= 0.5H;
9B - speed coefficient in non-pressure mode, ^B=0,82;
For rectangular pipes: Qc=1.35bH3p The semi-pressure mode is formed when 1,2hT<H<1.4hT In the semi-pressure mode, the free surface above the flow is preserved. A funnel is formed in front of the pipe, in which all floating objects that can clog the holes of the pipe can be tightened. Semi-pressure mode is unstable, it can break down to non-pressure or pressure mode.
Qc = CP**e*72*g* (H-hc)
hc=0.6hT
hT - pipe inlet height;
9P - speed coefficient of the semi-pressure mode 9P=0,85
®T - total cross-sectional area of the entrance;
e - the coefficient of lateral compression; ®T it is easy to calculate for both circular and rectangular cross-sections.
The pressure mode is formed at H>1.4hT. At the beginning of the pipe, a vacuum zone is formed at the entrances of the head, which can lead to the destruction of the embankment above the pipe. In order to eliminate the vacuum zone, the inlet head is arranged with a curved outline so that the flow smoothly enters the curve.
qc = pb*mc* V2 * g * (H - hc) - (iw - i)
0H=0,95 - the speed ratio of the pressure mode;
l h i - the length and slope of the pipe;
iW - the slope of the friction;
iW=Q02/K0
K0 - flow characteristics of a fully filled pipe[6]. Academic Research, Uzbekistan 1966 www.ares.uz
RESULTS AND DISCUSSION
During the study period, Tashkent-Sirdarya direction was chosen as the experimental site. This is because the uchachtka direction is characterized by highspeed and high-speed trains. For this reason, the technical case of the road in such networks is of great importance. We can see the case of artificial structures in the railway network from the tables presented below[7,8].
Table-1
№ Pipe states Quantity %
KM3367-3436 pieces
1) gravity 36 59
2) semi-pressure 2 3
3) pressure level 23 38
Condition of the culvert
40
1) gravity 2) semi-pressure 3) pressure level
CONCLUSION
Conclusions based on the results of studies of culverts can be made as follows it is necessary to study the state of the water-conducting pipes located on high-speed and high-speed lines and its effect on the structure of the movement. It is necessary to conduct detailed surveys of the condition of culverts for high-speed sections, because pipe failures negatively affect the condition of the track structure and rolling stock.
REFERENCES
1. Hydraulic calculations of culverts under road embankments. Methodological guidelines - N. Novgorod: Nizhny Novgorod State Archit. - building it. un-t, 2011. -18 p.
2. S.T. Djabbarov. Kompleks design of new railways. 2018. -156p/
3. V. M. Lisov Road culverts. - M.: Inform. - ed. center "TIMR", 1998. - 140 p.
4. Abdualiev E.B., Embergenov A.B. Case of waterproofing pipes on railways (https://www.scientificprogress.uz/ International Scientific-Practical Distance Conference «The 21st Century Skills for Professional Activity»(2021),( pp. 184185).
5. Abdualiev E.B., Uralov A. Sh. Culverts on the railway track https://www.scientificprogress.uz/ International Scientific-Practical Distance Conference «The 21st Century Skills for Professional Activity»(2021), (pp. 186188).
Abdualiev E.B., Abdukarimov A.M. Increase of productivity and reliability of control of rails. Architectural and construction science and period materials of the Republican scientific and practical conference part №. 2 T.: 2017y. 24-26p.
6. Abdualiyev E.B. (2019) "Research of surface condition of the rails rolling on sections of high-speed and high-speed train traffic, ," Journal of Tashkent Institute of Railway Engineers: Vol.15:Iss.2,Article14.Available at: https: //uzj ournal s .edu.uz/tashiit/vol 15/iss2/14
7. Abdualiyev E.B. (2019) "Research of surface condition of the rails rollingon sections of high-speed and high-speed train traffic," Journal of Tashkent Institute of Railway Engineers: Vol.15:Iss.3,Article4. Available at: https: //uzj ournals.edu.uz/tashiit/vol 15/iss3/4
