SU947270A1 - Combination lining of underground water duct - Google Patents

Description

The invention relates to hydraulic engineering and can be used in the construction of pressure underground pipelines of hydroelectric power stations and spillways of hydroelectric facilities.

Known combined lining of a pressure underground underground conduit, consisting of an external concrete ring and an inner steel lining, including a shell and stiffeners, which are steel single-wall rings [1].

The disadvantage of this design of the lining is that with large pressures of groundwater requires a large thickness and height of the stiffeners.

The lining of an underground water conduit is also known, including an external concrete ring and an inner steel shell equipped with closed annular stiffeners filled with concrete [2].

A disadvantage of the known design is its complexity, as a result of which its implementation requires large labor costs.

The purpose of the invention is to simplify the design. tion lining.

This goal is achieved in that the stiffeners are made composite, consisting of a middle ring of a T-shaped section ⁵ and two lateral rings of rectangular cross section.

In FIG. 1 shows a water conduit with a proposed lining a longitudinal section; in FIG. 2 - node 1 in FIG. 1.

The lining includes an outer concrete ring 1, an inner steel shell 2, and composite stiffeners made of a middle high ring 3 of a T-shaped section and two lateral low rings - stress concentrators 4 of rectangular cross section, the annular zone 5 between which is filled with concrete of the ring 1.

The dimensions of the stiffeners, as well as the distance between the middle 3 and side rings 4 (a) and between adjacent side rings (b), are determined depending on the size of the water conduit and the loads perceived by its lining. The optimal distance a between the middle and side 4 rings of the rib is such that j between the line connecting the edges of the shelf of the T-shaped ring 3 with the side rings 4, 5 and the axis of the conduit forms an angle of 45 °, i.e. stress propagation angle in concrete when a load is applied to it (compressive or tensile).

When the internal pressure of water P is greater than the external pressure of groundwater p (P> p) to the steel shell 2, the internal pressure is partially perceived by the shell 2 and rings 3 and 4 and partially transferred to the concrete ring 1 and through it to the array 15 rocks about.

When emptying the water conduit, the steel shell 2 under the influence of external groundwater pressure p moves inside the water conduit, trying to separate from the concrete ring 1,. However, this is prevented by the embedment of the middle T-rings 3 into the concrete ring 1, and in concrete, in the space between the middle 3 and the lateral 4 rings of the stiffeners, annular zones of concrete are formed, working together with the T-rings and are in a complex stress state: on the one hand they try to separate from the concrete ring 1, on the other - run compression together with _T-30 kol- Tsami.

At high groundwater pressures, the annular zones 5 of concrete can separate from the concrete ring 1 along the joint-cracks с and together with rings 3 and 4 form composite stiffeners, ensuring reliable operation of the shell.

The presence on the shell 2 of the lateral rings 4 of rectangular cross-section provides the formation of organized seams-cracks 7 in predetermined directions. After filling the water conduit with water, the sheath 2 is pressed against the concrete ring 1, the joint-cracks 7 are closed, and the lining works in a predetermined pressure mode.

The application of the invention will simplify the design of the lining of an underground water conduit while ensuring its reliable operation both on the perception of internal water pressures and when exposed to external loads.

Claims (2)

The invention relates to hydraulic construction and can be applied in the construction of pressurized underground water conduits of hydroelectric power stations and waterworks of hydrosystems. A known combined lining of a pressured underground water conduit consisting of an outer concrete ring and an inner steel lining, including a shell and stiffeners, is single-wall steel rings 1. The disadvantage of this lining design is that large thickness is required for large groundwater pressures. and the height of the ribs. The groundwater conduit lining is also known, which includes an outer concrete ring, an inner steel sheath provided with closed annular stiffening ribs filled with concrete 2. A disadvantage of the known construction is its complexity, as a result of which its implementation requires a lot of labor. The purpose of the invention is to simplify the design of the lining. This goal is achieved by the fact that the stiffening ribs are composite, consisting of a middle T-shaped cross-section ring and two side rectangular cross-section rings. FIG. 1 shows a conduit with a proposed longitudinal section lining; in fig. 2 - node 1 and FIG. 1. The lining includes an outer concrete ring 1, an inner steel shell 2 and composite stiffeners made of a medium high ring 3 of T-shaped cross section and two lateral low rings - concentrators 4 rectangular cross-section voltage, the annular zone 5 between which is filled with concrete rings 1. The dimensions of the stiffeners and the distances between the middle 3 n lateral rings 4 (a) and between the adjacent lateral rings (b) are determined depending on the size of the conduit and the loads perceived by its lining. The optimal distance a between the middle and side 4 edge rings is such that a 45 ° angle is formed between the line connecting the edges of the shelf of the T-shaped ring 3 with the side rings 4 and the axis of the conduit. stress spreading angle in concrete under load (compressive or tensile) applied to it. When internal water pressure P is applied to a steel shell 2 greater than the external pressure of groundwater p (P p), the internal pressure is partially perceived by the shell 2 and rings 3 and 4 and is partially transmitted to the concrete ring 1 and through it to the rock mass . When the water conduit is emptied, the steel shell 2 under the action of the external pressure of the groundwater r mixes into the water conduit, striving to separate from the concrete ring 1,. However, this prevents the embedding of the middle T-shaped rings 3 into the concrete ring 1, and in concrete, in the space between the middle 3 and the side 4 rings of stiffeners, annular zones of concrete are formed, which work together with the T-shaped rings and are located in complex stress state: on the one hand they try to separate from the concrete ring 1, on the other hand they work in compression together with T-rings. At high pressures of groundwater, the annular zones 5 of concrete can be separated from the concrete ring 1 along the joints-cracks 7 and, together with rings 3 and 4, form composite stiffeners ensuring reliable operation of the shell. The presence of 2 side rings of 4 rectangular sections on the casing ensures the formation of organized seams-cracker 7 in predetermined directions. After filling the water conduit with water, the casing 2 is fixed to the concrete ring 1, the seams-cracks 7 are closed, and the lining works in the specified pressure mode. The application of the invention will make it possible to simplify the construction of the lining of an underground conduit, while ensuring its reliable operation both on the perception of the internal pressures of the water and on the external loads. A combined lining of an underground water conduit comprising an outer concrete ring and an inner steel shell provided with annular stiffening ribs filled with concrete, characterized in that, in order to simplify the design, stiffeners are made of composite, consisting of a middle ring of T-shaped section and two side rings of rectangular cross section. Sources of information taken into account in the examination 1. Designation for the design of drainage of underground hydraulic structures. M., 1973, p. 31, Fig. 22 2. USSR author's certificate number 642558, cl. F 16 L 1/00, 1978 (prototype).