CN1030467A

CN1030467A - Pressure piping

Info

Publication number: CN1030467A
Application number: CN88103768A
Authority: CN
Inventors: 大卫·D·A·皮谢德
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-23
Filing date: 1988-06-23
Publication date: 1989-01-18
Also published as: ZA884489B; GB2207935B; GB2207935A; GB8714618D0; GB8814971D0

Abstract

A kind of method of constructing the pressure piping bend pipe in the rock stratum comprises: excavation cavity 1 in rock, in order to construct bend pipe, concrete member 6 is set in cavity, and pipeline passes through wherein, and forms bend pipe therein; Between member and rock chamber wall, inject the pulpous state pressure medium, act on inside pressure on the member in order to generation.Member has predetermined shape, and has and bend pipe concave edge outer surface adjacent, and outer surface is along being rectilinear or convex on the longitudinal section of pipeline rout, and in order to reducing or to eliminate tensile stress on inner surface of component as far as possible, member can be ovate.

Description

Pressure piping

The present invention relates to the improvement of water power device or the used pressure piping of pumped storage device one class water resource system.

Be to bear load in the existing design of set pressure piping in the rock stratum with steel, cement lining, linerless rock or with the mixed construction of steel and cement layer or steel, cement and lithosphere formation, be performance in mixed construction, share this load by certain predetermined mode according to above-mentioned two or three material.Though steel lining generally can bear maximum load, but because expense is excessive, often replace steel lining in some cases with concrete lining, at this moment, earlier concrete lining is placed in the rock cavity of excavation, between chamber wall and concrete lining, is in the milk subsequently, make the outer surface of lining receive extraneous pressure, and make the radial compressive stress that acts on the lining surpass the tensile stress that when pressure piping is worked, acts on the lining, thereby reduce the danger that cracks and make crack propagation in the concrete towards pipeline center.

When the lineal shape concrete lining has identical sectional shape on its whole length, and the outer surface of concrete lining and limit the hydraulic pressure internal surface of pipeline when all rounded, the method for this " precharge pressure " is very fruitful.But, in the time must bend pipe or breeches pipe being set in pressure piping, generally just be difficult to make lining to have very suitable shape, some suffered stress in zone is tensile stress in the lining because the method for precharge pressure can make, rather than the required radial compressive stress that adds in advance, for example: at the concave edge of bend pipe, the outer surface of lining is along being spill on the longitudinal section of pipeline rout, therefore, outside slurry acts on this regional pressure and can cause very big tensile stress on the hydraulic pressure internal surface of adjacency, only can impel crackle to produce, and can not suppress the generation of crackle.

On pressure piping, make bend pipe or breeches pipe can overcome this difficulty with the heavy wall steel lining.But, when internal diameter of the pipeline be 5m or bigger, when wall thickness is several centimetres, this lining is just very expensive.When the required load that bears is very little, once used the lining of strengthening concrete for making bend pipe and breeches pipe, but in the power station that peak load is controlled automatically, to worry to act on the fatigue effect that continuous alternating stress produced on the pressure lining, therefore also must use the performance of strainometer one quasi-instrument monitoring reinforcement concrete lining sometimes.

From on the one hand, the invention provides the method for the rock stratum, constructing the pressure piping bend pipe, comprise: excavation is in order to construct the cavity of bend pipe in the rock stratum, concrete member is set in cavity, pipeline passes through wherein, and form tube bends therein, member have internal surface and with rock chamber wall outer surface adjacent; Pressure medium is injected between external surface of structural member and the rock chamber wall, in order to produce an effect inside pressure on the outer surface; Wherein, concrete member has predetermined shape, in order to reducing or to eliminate tensile stress on its internal surface as far as possible, therefore, be rectilinear basically or convex normally along having a part in the described outer surface adjacent on the longitudinal section of pipeline rout at least with the bend pipe concave edge.

The present invention also provides a kind of structure that are arranged in the excavation rock stratum cavity from another point of view, comprising: concrete member, pressure piping be by wherein, and form tube bends therein, member have internal surface and with rock chamber wall outer surface adjacent; Pressure medium, be arranged between the outer surface and rock chamber wall of member, in order to produce an effect inside pressure on the outer surface, wherein, concrete member has predetermined shape, in order to reduce or eliminate the tensile stress on its internal surface as far as possible, therefore, along on the longitudinal section of pipeline rout, be rectilinear substantially or convex normally with having a part in the bend pipe concave edge outer surface adjacent at least.

The pressure piping of Xing Chenging just can adopt the method to concrete member " precharge pressure " like this, makes pipeline in use stand sizable internal pulsations hydraulic pressure, prevents large-area tensile stress simultaneously on the internal surface of tube bends.Therefore, can in the very big pipeline of when work internal stress, adopt bend pipe and needn't adopt very expensive heavy wall steel lining.

When making concrete member, be the precompressed effect that might estimate pressure medium quite exactly, because can determine its load condition fully according to predetermined shape by predetermined shape.Adopt present The common calculation methods, as adopt the elemental microanalysis method of deciding of computer, just might determine to have the interior stress of member of suitable shape quite exactly, therefore, just can adopt to add reinforcing bar, additionally add reinforcing bar or answer and carry out suitable protection with the method for steel plate if a certain internal surface of hydraulic action that is subjected to is not subjected to due precompressed.The state of precompressed can be used instrument check at the scene, but the state that if can measure stress in advance just can be saved time and expense.Therefore being preferably in the design phase just adopts and decide the stress phase of elemental microanalysis method forecasting institute with member, selectes the reservation shape of concrete member.

In suitable rock, construct large-scale breeches pipe with said method and just can save a lot of expenses.Pressure piping generally has than the better anti-fatigue performance of the lining of other type when bearing internal pulsations pressure owing to the transient phenomena of waterpower (being electric power sometimes).

Bend pipe in the pressure piping is a part of off-straight state in the pipeline.And the present invention is specially adapted to ducted breeches pipe, just the part of pipeline fork.For example, " Y " shape pipe just has three curved sections, and each curved section has a concave edge, and as mentioned above, concrete member just has one to be that concave edge is adjacent therewith for outer surface rectilinear or normally convex basically.

For better simply bend pipe in the pipeline, it is rectilinear or the outer surface of convex (on the longitudinal section) substantially that this member has at the position adjacent with the bend pipe concave edge.The accurate shape at this concave edge position and concavity preferably adopt well-knownly decides elemental microanalysis method and pre-determines, thereby eliminates any tensile stress at bend pipe concave edge position on inner surface of component.

Concrete member preferably along pipeline rout from the pipe of all around going for a stroll, and its outer surface entirely is circular usually.Member can form a cylindrical body or form a truncated cone, has end face flat or circle, and this moment and bend pipe concave edge outer surface adjacent are along can being rectilinear on the longitudinal section of pipeline rout.Perhaps, truncated cone is particularly suitable for " Y " shape breeches pipe, one of them fork passes the small end of cone, two forks then pass big end in addition, this member also can form oval body, ellipsoid or spheroid, and this moment and bend pipe concave edge outer surface adjacent are along convex normally on the longitudinal section of pipeline rout.

This class concrete member can be an asbestos cement, also can adopt other suitable materials, but preferably pure concrete or strengthen concretely, concrete is liquid pouring, and before the injection pressure medium it is solidified.

Usually in rock, excavate and the identical shaped cavity of concrete member, as rock matter better and excavation accurately, the chamber wall is lining more just, but had better be again with shotcrete one class wadding, excavate very irregular state on the rock face to eliminate, and in the excavation area, form and the corresponding cavity of concrete member shape.

Although being formed for the space of pressure medium around concrete member is not very main problem, had better constitute a space in this zone with model or the filler that is easy to eliminate.Usually with pure concrete or add reinforced concrete constructing concrete member, shed model or removing filler then.Usually also inner model must be set, in order to form side opposite.

More favourable way is: before the injection pressure medium, earlier water is made a bet into around the zone of concrete member outer surface (for example in pressure selected, be similar to, equal or exceed the internal work pressure that will be subjected to when working later in the pipeline in formation), and determine its leak rate.Like this with regard to the denseness and the type of optional level pressure power media.This method in order to the lineal shape pressure piping and the band bend pipe the pipeline precharge pressure time be of great value.

In addition, the invention provides the method that the cavity lining that excavates in the rock stratum is constituted pressure piping, comprising: pipelining member is set in cavity, makes the outer surface of member adjacent with the chamber wall; Between outer surface and chamber wall, water is injected, and determine the leak rate of water under selected pressure with pressure selected.

Can be with water, and afterwards with pressure medium by be located in the member or the chamber wall on pipe-line system inject in the suitable zone.

Must prevent the generation of air pocket in pressure testing, this can adopt the exhaust tube that is located in the member to come discharging air.Exhaust tube also can discharge the water of pressure testing when injecting the permanent pressure medium afterwards.

Pressure medium can adopt various cement slurrys, can make various gluey cement slurries in case of necessity and have the cement slurry of cement plasticizing agent or make the slurry that expands to be in the milk, and makes it solidify the preloading condition that the back maintenance adheres to specification.Sometimes preferably making needs the zone of injection pressure medium to have enough radial width, makes the slurry hardening so that add sand stage by stage in cement.Can use the slurry that expands in case of necessity, this can increase the endurance of precompressed.

The buffering person in charge, dashpot of rock etc. around also having, the structure relevant with pressure piping are arranged.

Below describe with regard to most preferred embodiment of the present invention and accompanying drawing thereof.

Fig. 1 is the sectional arrangement drawing that is provided with the pressure piping of breeches pipe.

Fig. 2 is the II-II drawing in side sectional elevation of pressure piping among Fig. 1.

As shown in the figure, excavation cavity 1 in rock stratum 2, and reserve and build by laying the required surplus of concrete wall body, the requirement that makes it meet initial analysis and construct facility.The lining 4 that rock chamber wall 3 multiple useful shotcretes or similar material constitute, in order to eliminate the irregular and asymmetric state of wall, and constituting the outside profiled surface of hollow structure 5, structure 5 can be very fast at inside and outside stress suffered when receiving pressure and be analyzed exactly.In most preferred embodiment, hollow structure are ovate, in pure concrete is arranged or strengthens concrete member 6, in member 6, form " Y " shape breeches pipe 7 of pressure tube.Leave the space between lining 4 and concrete member 6 outer surfaces, be filled with the slurry 8 as pressure medium in the space, slurry 8 produces an inside pressure that acts on the member.As shown in Figure 1, the outer surface of member makes slurry pressure produce pressure stress in the outer surface region of concrete member along being convex on the longitudinal section of pipeline rout.Breeches pipe is made of three curved sections of pressure tube, and the position 9(on the concrete outer surface adjacent with the concave edge of curved section is the position, radius of curvature center of curved section) not to be shaped along the profile of curved section, but convex.

During breeches pipe in constructing pressure piping, excavation cavity 1 is multiple then to serve as a contrast 4 earlier.Add hollow mould or the filler of easily eliminating 10 on 4 at lining again,,, and it is solidified and after forming member 6, shed hollow mould or water is injected the space to remove filler at placement of concrete in order to form the space between lining and the concrete outer surface.Water is to inject by the pipe-line system that is located in the concrete member 6 or be located in the space between member and the wadding.Hydraulic pressure should be equal to or greater than the maximum functional internal pressure of being born after the pipeline when work.Determine the leak rate of water.Just can select the type and the denseness of slurry.Utilize these pipes to the space used pressure when reaching water filling that is in the milk then.After finishing grouting, pipe is cleared up in water filling again, and makes water stay in the pipe and the outlet port.If find later on since around rock displacement or because stock losses reduces the precharge pressure on the concrete member in rock empty to some extent, just can utilize these pipes to add slurry inward.

Figure 2 shows that the cross section of circular section lineal shape pipe section.Crag 3, lining 4, slurry 8 is corresponding with each one of breeches pipe with concrete member 6 each one, but the concrete member that forms this part pipeline has better simply pipe cross-section certainly.Concrete tube body and serve as a contrast annular space between 4 before pressure testing and grouting, is to seal by wadding is directly contacted on a very short segment length of pipeline with concrete, just no longer has hollow mould or easy-clear filler on this segment length.After the pressure slurry solidifies, before the extensional pipeline, repair this section annular space with pneumatic tool.

The method of common this improvement pressure piping is best suited for rock matter area preferably, although also there is some defective here, the Young's modulus of rock also can surpass the slurry in the space and constitute the concrete member of pipeline.Around pipeline, no matter in Vertical direction, or widthwise, outer rock is enough to avoid produce in its surface the displacement phenomenon in pressure testing and injection grout.

In the appearance of pipeline, except that carry out necessary appearance by reliable structural analysis, also must consider the hydraulic pressure load.In real work, between this requirement aspect two, there is not tangible contradiction.

Aspect total and can carry out some and revise on specific embodiments, this is clearly for the personnel that are familiar with this technology to the present invention.These modifications should be included in the scope of invention.

Claims

1, a kind of method of constructing rock stratum internal pressure tube bends comprises: excavation is in order to construct the cavity of bend pipe in rock; Concrete member is set in cavity, have pipeline to pass through wherein, and form tube bends therein, member have internal surface and with rock chamber wall outer surface adjacent, injection pressure medium between external surface of structural member and rock chamber wall makes to produce a kind of effect inside pressure on the outer surface; Wherein, concrete member has predetermined shape, in order to reducing or to eliminate tensile stress on its internal surface as far as possible, therefore, along on the longitudinal section of pipeline rout, with bend pipe concave edge outer surface adjacent in to have a part at least be rectilinear or convex normally basically.

2, according to the described method of claim 1, wherein, pipeline is " Y " shape, has three curved sections, each curved section respectively has a concave edge, and the concrete member outer surface adjacent with concave edge is rectilinear or convex normally basically.

3, according to claim 1 or 2 described methods, wherein, concrete member is ovate.

4, according to claim 1,2 or 3 described methods, wherein, on the wall of rock chamber, wadding is arranged again, in order to the irregular status on the elimination pledge excavation face, and in formation of excavation part and the corresponding shape of concrete member.

5, according to method described in above arbitrary claim, wherein, with hollow mould or easily eliminate filler and form a space around the concrete member, in order to the injection pressure medium.

6, according to the described method of above arbitrary claim, wherein, before the injection pressure medium with pressure selected with water inject the concrete member outer surface around, and determine the leak rate of water under selected pressure.

7, set structure in the cavity that excavates in the rock stratum comprise: concrete member, pressure piping passes through wherein, and forms tube bends therein, member have internal surface and with rock chamber wall outer surface adjacent; Pressure medium between external surface of structural member and rock chamber wall is in order to generation effect inside pressure on the outer surface; Wherein, concrete member has predetermined shape, in order to reducing or to eliminate tensile stress on its internal surface as far as possible, therefore, along on the longitudinal section of pipeline rout with to have a part at least be rectilinear or convex normally basically in the bend pipe concave edge outer surface adjacent.

8, the construction method of rock stratum internal pressure tube bends is substantially as the above accompanying drawing illustration of pressing.

9, the structure that are provided with in the cavity that excavates in the rock stratum are substantially as the above accompanying drawing illustration of pressing.