RU2223361C2 - Structure protecting against earth flow - Google Patents

Abstract

FIELD: hydraulic engineering. SUBSTANCE: structure can be employed as sill protection to prevent possible congestion in chutes transporting sill mass, it includes dam with holes formed by tubes of rectangular or round shape with dimensions of area of cross-section diminishing in direction of earth flow. Tubes are interjoined rigidly with concrete to form solid structure-dam presenting arch form in plan with trapezoidal cross-section which back is vertical or has adverse gradient and which down-stream side is sloping gently. Structure protecting against earth flow can be formed by chain of dams with holes which dimensions gradually decrease as earth flows to size of hole ensuring carrying capacity of sill-conducting course. Ridges reducing friction force of large entrained stones against concrete are uniformly arranged over perimeter and entire length in round or square holes. Upper edge of dam carries dampers-absorbers of dynamic or impact action of boulders and large stones on dam. As upstream wall is silted height of dams in chain should be built up gradually. EFFECT: proposed structure is effective and reliable in operation thanks to increased strength and resistance dynamic and static pressure of earth flow. 3 cl, 8 dwg

Description

 The invention relates to hydraulic engineering and can be used as a mud screen to prevent possible congestion in the trays transporting mudflow, and thereby increase its transporting ability.

 Known anti-mudflow construction [1], containing a springboard, the inlet head of which is made in the form of a triangular prism, pointed with a tip towards the lead channel, iron posts, by means of which shields are attached to the springboard and reinforced concrete walls installed in the channel section. With the passage of the mudflow, its shock impact perceives the tip of the springboard. The crushed stream moves between the diving board and the walls. The remaining energy of the mudflow is perceived by the shields, they, in turn, transmit the power load to the hydraulic cylinders.

The disadvantages of this technical solution is that
- the device does not provide for extinguishing a stream containing large inclusions or boulders;
- from the pressure of mudflow on the shields, their destruction is possible, since they are installed across the mudflow;
- the device does not provide for the possibility of accumulation of dangerous fractions of mudflows.

 The closest technical solution is a self-regulating structure [2], which consists of a mud-holding through dam, equipped with a selector channel with side walls to the full height of the dam, while the side walls of the channel are protruding towards the upper and lower heads of the structure. The presence of a through channel and a through dam provides the ability to control the mass of mudflow particles.

The disadvantages of this technical solution is that
- the mud-retaining part of the dam can become clogged with stones and boulders of relatively small diameter and blockage of the dam will gradually occur,
- boulders of large sizes will pass through the selection channel, which can clog the selection tray and thereby reduce the channel capacity;
- the planned structural solution of the dam does not allow full use of the strength properties of concrete, and the stability of the dam is ensured by the dead weight of the dam.

 The purpose of the invention is to increase the efficiency and reliability of the work, as well as the strength and stability of the structure from the dynamic and static pressure of the mudflow.

 This goal is achieved by the fact that the mud-retaining dam is made in an arch form in plan from pipes of rectangular or round shape of such a diameter that boulders smaller than, say, 1-1.5 m in size will pass through it unhindered, and larger ones will linger in the upper pool. Stones less than 1-1.5 m in size do not pose a threat to the seeding tray and can be transported. The arch-shaped construction of the retaining dam allows full use of the bearing capacity of concrete, as in this case, the concrete works in compression. The entire load from the pressure of the mudflow will be perceived by the sides of the gorge, on which the arched spill-resistant dam rests. The stability of the through arched mud-holding dam is ensured not by the friction and adhesion forces of the contact surface of the base, depending on the weight of the structure, but by the reactions of the sides of the gorge. This allows you to design an arch dam with parameters determined mainly by the condition of the strength of the material of the structure and its adjacency to the shores. Due to the nature of its work, the arched dam does not need significant weight.

 The mudflow protection structure consists of many round or square pipes with decreasing cross-sectional area in the direction of mudflow and rigidly interconnected with concrete, forming a naturally unified whole structure having an arched plan with a trapezoidal cross section, the uphill of which is vertical or has the opposite slope, shallow shallow.

 The mudflow protection structure may consist of a cascade of dams, the size of the holes of which gradually decreases along the course of the mudflow, and the size of the latter depends on the transporting ability of the mudflow channel. As silt of the upper pool is silted with boulders that do not pass through the structure, which will happen in several decades, the height of the dam can gradually increase. The downstream slope will be concreted and serve as a rapid current.

 In FIG. 1 shows a longitudinal section of a mudflow protection structure consisting of a cascade of dams with holes decreasing along the course of the mudflow; figure 2 is a cross section 1-1 of the upper dam, consisting of round pipes, rigidly interconnected with concrete; figure 3 is a cross section 1-1 of the upper dam, consisting of rectangular pipes of such a size that boulders smaller than 1-1.5 m will pass through it without hindrance, and larger ones will linger in the upper pool; figure 4 is a cross section 2-2 of the lower dam, consisting of round pipes of a smaller diameter than in the upper dam, rigidly connected to each other by concrete; in FIG. 5 is a cross-section 2-2 of a lower dam, consisting of rectangular pipes of reduced size; Fig.6 is a plan view of the arch structure of a mudflow protection structure made of rectangular or round pipes rigidly connected to each other by concrete, forming a single solid structure, the uphill of which is vertical or has a reverse slope, perceives the mudflow pressure and transfers it to the sides gorges; in FIG. 7 is a longitudinal section of a mud protection structure after a dam has been built upon siltation of existing mud retaining dams; in FIG. 8 - structural design of the pipe connection unit with the skates located inside the holes uniformly around the perimeter and along the entire length and provided with shock absorbers and dampers provided in the upper face from dynamic and impact effects.

 On the basis of 1, a mud protection structure is arranged, consisting of a cascade of dams 2, 3 with holes decreasing along the course of the mudflow. The upper slope of the dams is strengthened from erosion by the tooth 4. The upper dam 2 is made of pipes of round 5 shape, rigidly interconnected with concrete 6, or rectangular 7 shape. The size of the pipes is selected taking into account the fractional composition of the mudflow 8 so that boulders less than 1-1.5 m in size freely pass through the structure, while larger ones are delayed in the upstream. The bottom dam 3 is made of pipes of a round 5 or rectangular 7 shape of a smaller transverse dimension, rigidly interconnected by concrete 6.

 Debris protection is performed with a trapezoidal cross-section. Downhill slope 9 is shallow. The uphill slope 10, perceiving mudflow pressure, is vertical or has a reverse slope. Arched in terms of the design of the mud protection structure allows full use of the bearing capacity of concrete, as concrete in this case works for compression. The entire load from the pressure of the mudflow is perceived by the sides of the gorge, on which the arched spill-resistant dam rests.

 In the upper face of the dam, dampers-dampers 11 from the dynamic and impact of boulders and large stones on the dam are provided. Inside the round or square holes, skates 12 are provided uniformly around the perimeter and along the entire length, which reduce the friction force of large drawn stones on concrete.

 During operation, as the silt of the upper pool is silted with boulders that have not passed through the building 13, 14, 15, the height of the dams gradually increases 16, 17. The lower slope of the dams serves as a rapid current 18. It is envisaged that the upper pool of the built dams will be strengthened with reinforced concrete ponim 19.

 Mudflow protection works as follows. Debris protection structure delays certain fractions of the mudflow, destroying or clogging the selector tray. To increase the efficiency of the work, the structure may consist of a cascade of dams 2 and 3, arranged on a rocky base 1, with holes decreasing along the course of mudflow.

 The pressure of the mudflow 8 is perceived by a gentle uphill slope 9 of the dam 2. The arch-shaped construction of the mud protection structure allows to fully use the bearing capacity of concrete 6, because concrete in this case works for compression. The entire load from the pressure of the mudflow is not perceived by the forces of friction and adhesion of the contact surface of the base, depending on the weight of the structure, but by the reactions of the sides of the gorge, on which the arched mud-holding dam is based. This allows you to design an arch dam with parameters determined mainly by the condition of the strength of the material of the structure and its adjoining to the shores.

 The bottom slope of the dam 10 is designed flat from the condition of the stability of the structure.

 The uphill slope 9 of the dam is strengthened from erosion by the tooth 4.

 Debris flow 8 passes through round 5 or rectangular 7 openings of the mud-holding dam 2. Moreover, fractions of less than 1-1.5 m in size freely pass through structure 8, while larger ones are retained in the upper pool 14.

 The size of the openings of the inlet and outlet round 5 or rectangular 7 sections within one arched dam is different. The size of the inlet section is larger than the size of the outlet section, which significantly improves the process of mudflow through the dam, allows more uniform use of the strength properties of concrete within the dam body and makes the structure more economical.

 To increase the efficiency of the mud-holding structure, a cascade of dams with holes decreasing along the mudflow is arranged. The mudflow 8 passes further through the holes of the dam 3 with a smaller cross-sectional size of the holes. In the upper pool of this dam, smaller fractions of the mudflow 15 are retained.

 During operation, as the silt of the upper pool is silted up by boulders that have not passed through the structure 13, 14, 15, which will occur in several decades, the height of the upper 16 and lower 17 dams gradually increases. At the same time, the bottom slope of the dams is concreted 18 and serves as a rapid current. The upper pool of the built dams is reinforced with reinforced concrete ponur 19.

 Damper absorbers 11 are provided in the upper edge of the dam for protection during mudflows from dynamic and impact of boulders and large stones.

 To reduce the friction of large entrained stones on concrete inside the round or square holes of the dams, skates 12 are provided uniformly around the perimeter and along the entire length.

 Mudflow protection increases the efficiency and longevity of the operation of the mud-removing structures, excluding the passage of large fractions of mudflow dangerous to them. The proposed constructive solution reduces the cost of construction in comparison with similar mud-holding structures.

Sources of information
1. A.S. 1625937 USSR, MKI E 02 B 8/06. Anti-mudflow construction / Gavardashvili G.V., Teliashvili D.S., Diakonidze R.V., Kvirkvelia I.B., Gvishiani Z.G. (USSR); application 03/20/89; publ. 02/07/91, bull. 5 (analogue).

 2. A.S. 1604907 USSR, MKI E 02 B 8/06. Self-regulating construction / Baljyan P.O. (USSR); application 01/21/88; publ. 11/07/90, bull. 41 (prototype).

Claims (4)

1. Mudflow protection structure, consisting of a dam having openings for passing mudflow, characterized in that the openings are formed by a variety of round or square pipes made with decreasing cross-sectional area in the direction of mudflow and rigidly interconnected with concrete to form a single unitary structure - a dam having in plan an arched shape with a trapezoidal cross section, the uphill slope of which is vertical or has a reverse slope, and the lower sloping. 2. Mudflow protection structure according to claim 1, characterized in that it is provided with additional dams with the formation of a cascade of dams, the size of the holes of which gradually decreases along the course of the mudflow to the size of the last dam of the cascade, which provides the transporting ability of the selector channel. 3. Mudproof building according to claim 1, characterized in that in the round or square holes, skates are evenly distributed around the perimeter and along the entire length, reducing the friction force of large drawn stones on concrete. 4. Mudguard construction according to claim 1, characterized in that damper dampers from the dynamic and impact effects of boulders and large stones on the dam are located on the upper edge of the dam.

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