CN101319942B - Hydraulic prototype test method of underwater shield tunneling structure model - Google Patents

Abstract

The invention relates to a hydraulic pressure prototype test method for a structure of a shield tunnel which includes: A, mounting an annular anchor: vertically arranging a tunnel structure (2) on the ground; vertically arranging a front annular hoop beam and a back annular hoop beam(3a,3b) on the outer surface of the tunnel structure (2); alternatively anchoring an annular hoop anchor cable (5) with a load meter on the front annular hoop beam and the back annular hoop beam(3a,3b); fixing the other end of the annular hoop anchor cable (5) on the top rod of a jack (6) corresponding to the annular hoop beams(3a,3b); B, padding friction reducing layers: symmetrically padding 3 to 5 sections of friction reducing layers with degressive friction coefficients between the tunnel structure (2) andthe annular hoop anchor cable (5); C, testing: using the jack (6) to tight the annular hoop anchor cable (5) and testing and analyzing the load capacity and the mechanical property of the tunnel structure (2) by a corresponding measuring instrument. The method more factually simulates the effect of the hydraulic pressure of an environment to an underwater tunnel structure and provides a basis forthe design and construction of the underwater tunnel structure for ensuring the construction and operating safety of the tunnel.

Description

A kind of hydraulic pressure prototype test method of underwater shield tunneling structure

Technical field

The present invention relates to a kind of test method of shield tunnel construction, relate in particular to a kind of hydraulic pressure prototype test method of underwater shield tunneling structure.

Background technology

Underwater shield tunneling structure at the bottom of seabed, the river is under the external hydrostatic pressure effect, and the distributional pattern of the hydraulic pressure that it bears is big " bulb " shape in little bottom, top.During construction and operation, the variation in water pressure that the tunnel bears is very big, the present trend that maximizes of tunnel cross-section in addition, and the non-homogeneous hydraulic pressure that bears in construction time and operation phase of shield tunnel be can not ignore the effect of tunnel structure under water.By the role and influence of simulation bulb-shaped hydraulic pressure, can provide the scientific and reliable test basis to the design and the construction of underwater shield tunneling structure, to guarantee the construction and the operation safety in tunnel to tunnel structure.At present still not having effective ways can apply bulb-shaped hydraulic pressure to tunnel structure when the prototype test of tunnel structure, this is a problem demanding prompt solution in current Tunnel Design and the construction.

Summary of the invention

Purpose of the present invention just provides a kind of prototype test method of underwater shield tunneling structure hydraulic pressure, this method can apply the little bulb-shaped hydraulic pressure in big bottom, top to shield tunnel construction, simulated environment hydraulic pressure is to the role and influence of tunnel structure more truly, thereby design and construction to underwater shield tunneling structure provide more scientific and reliable test basis, to guarantee the construction and the operation safety in tunnel.

The present invention realizes its goal of the invention, and the technical scheme that is adopted is:

A kind of hydraulic pressure prototype test method of underwater shield tunneling structure, its practice is:

The duct pieces of shield tunnel that A, installation hoop anchor cable will be embedded with strainometer, reinforcing bar meter is assembled into short cylinder shape tunnel structure, then tunnel structure is placed ground, and wherein axis normal is in ground; Former and later two vertical hoop beams are arranged at the outside surface of tunnel structure symmetrically, the hoop anchor cable of the vertical band loadometer more than two that distributes alternately is anchored on the forward and backward hoop beam, and the hoop anchor cable then is fixed on around the other end of tunnel structure after one week of surface on the push rod of lifting jack of corresponding hoop beam.

B, pad are established the antifriction layer and are filled up between tunnel structure and hoop anchor cable and establish the teflon antifriction layer that radian is a 250-290 ° of circular arc, this circular arc antifriction layer is distributed between the forward and backward hoop beam symmetrically, and the part of described antifriction layer hoop Liang Chu before be positioned to the both ends of described antifriction layer only respectively are divided into the 3-5 section that friction factor successively decreases.

The layout of C, testing tool is pasted on a plurality of foil gauges on the inside surface and outside surface of section of jurisdiction, and crack gauge is installed on the inside surface and outside surface of junction, section of jurisdiction, and displacement meter is installed on the inside surface of tunnel structure.

D, test outwards eject the push rod of lifting jack, the hoop anchor cable is strained, tunnel structure is imposed radial pressure, by foil gauge, displacement meter, crack gauge and strainometer, reinforcing bar meter the load capacity of loading and the mechanical property parameters of tunnel structure are tested simultaneously, and test data is imported Computer Analysis calculate, obtain test result.

Test method of the present invention and principle are: the short cylinder shape prototype tunnel constitution water level land that true duct pieces of shield tunnel is constituted is positioned over ground, because the concrete Poisson ratio in section of jurisdiction is very little, so can keep the identical plane strain state that is in of tunnel structure body and long tubular tunnel structure really.Adopt the hoop load mode, the hoop anchor cable that utilizes the static(al) jack pair to be installed on the forward and backward hoop beam applies stretching force, and tunnel structure is produced radially contact pressure.Because the hoop anchor cable is to the contact pressure of shield tunnel construction outside surface everywhere, become the relation of negative correlation with the suffered friction force of this place's anchor cable, so antifriction layer that the part position is provided with between hoop anchor cable and tunnel structure, can change the frictional resistance of hoop anchor cable and tunnel structure outside surface, and then the change contact pressure, thereby simulate of the effect of true hydraulic pressure to tunnel structure.Because antifriction layer in the past hoop Liang Chu rises and only is divided into the 3-5 section that friction factor increases progressively to the end, therefore also hoop Liang Chu, antifriction layer end, back hoop Liang Chu progressively increase progressively the suffered friction force of anchor cable in the past, make the hoop anchor cable then successively decrease successively to the contact pressure of shield tunnel construction outside surface, realized that tunnel structure top (back hoop Liang Chu) pressure is little, bottom (preceding hoop Liang Chu) bulb-shaped pressure distribution that pressure is big, thereby simulate suffered under water non-homogeneous (bulb-shaped) hydraulic pressure of tunnel structure more truly, test again subsequently.Therefore, the inventive method can be subjected under the condition of bulb-shaped hydraulic pressure at tunnel structure, measures its every mechanics parameter and performance.

Compared with prior art, the invention has the beneficial effects as follows:

1, can apply the big bulb-shaped hydraulic pressure in little bottom, top to shield tunnel construction, the role and influence of environment hydraulic pressure to tunnel structure are measured in serious site test, thereby design and construction to underwater shield tunneling structure provide more scientific and reliable test basis, to guarantee the construction and the operation safety in tunnel.

2, friction factor by the antifriction layer material and changing value thereof and control for loading value, thus contact pressure adjusted, simulating under different water level conditions, true hydraulic pressure makes the inventive method applicability strong for the effect of tunnel structure.

The above-mentioned A step is when installing the hoop anchor cable, the anchor cable locating device also is set on tunnel structure, this locating device is by the fixed bar of tunnel structure inside surface, the connection cross bar on the backstay of outside surface and the upper and lower surface of tunnel structure is formed, and fixed bar is connected with backstay and is fixed on the tunnel structure by connecting cross bar; The inside surface of backstay is provided with the anchor cable locating slot with the quantity and the form fit of hoop anchor cable, and every hoop anchor cable places in the corresponding anchor cable locating slot.

Like this, every hoop anchor cable can be positioned in the anchor cable locating slot, each bar hoop anchor cable is evenly spaced apart.Effectively avoid at the trial, the hoop anchor cable twines mutually, and influences applying of load, causes testing being difficult to the situation of carrying out.

The above-mentioned B step fills up when establishing the antifriction layer, the concrete practice that the part of antifriction layer hoop Liang Chu before be positioned to the both ends of described antifriction layer only respectively are divided into the 3-5 section that friction factor successively decreases is: the antifriction section at both ends is made of one deck teflon piece, the antifriction layer of preceding hoop Liang Chu is made of two-layer teflon piece, and scribble lubricant between two-layer teflon, remaining antifriction section is made of two-layer teflon piece.

The antifriction material that teflon is a kind of intensity height, cost is low, smooth utilizes the antifriction layer that it makes, and can reduce the friction factor between hoop anchor cable and tunnel structure effectively; And adopt two polyvinyl fluoride pieces to be stacked to constitute the antifriction layer, and utilize the slip of polyvinyl fluoride two interlayers, further reduce the friction factor of this place's anchor cable and antifriction interlayer; Coat lubricant at two-layer polyvinyl fluoride interlayer again, make the friction factor of anchor cable and antifriction interlayer reduce to minimum.Adopt this method, can be simply, realize that hoop Liang Chu in the past increases progressively to the friction factor of its end effectively.

The present invention is further detailed explanation below in conjunction with accompanying drawing and concrete embodiment.

Description of drawings

Synoptic diagram when Fig. 1 is embodiment of the invention test.

The hydraulic pressure distribution schematic diagram that Fig. 2 produces on the prototype shield tunnel construction when being embodiment of the invention test;

The force analysis figure of hoop anchor cable infinitesimal d1 when Fig. 3 is embodiment of the invention test.

The force analysis figure of prototype shield tunnel construction body infinitesimal dL when Fig. 4 is embodiment of the invention test.

Embodiment

Embodiment

Fig. 1 illustrates, and a kind of embodiment of the present invention is, a kind of hydraulic pressure prototype test method of underwater shield tunneling structure, and its practice is:

A, installation hoop anchor cable are embedded with 12 strainometers, 12 reinforcing bar meters altogether in all sections of jurisdiction 1 of whole tunnel structure 2, then tunnel structure 2 is placed ground, and wherein axis normal is in ground; Vertical former and later two hoop beams 3a, the outside surface that 3b is arranged at tunnel structure 2 symmetrically, the hoop anchor cable 5 of eight band loadometers alternately is anchored on forward and backward hoop beam 3a, the 3b, and hoop anchor cable 5 then is fixed on around the other end of tunnel structure after 2 surperficial weeks on the push rod of lifting jack 6 of corresponding hoop beam 3a, 3b; Former and later two rings

Hoop beam 3a, the last inboard of 3b have groove, with conveniently be anchored in another hoop beam 3b, the last hoop anchor cable 5 of 3a passes through.

When the hoop anchor cable is installed, anchor cable locating device 8 also is set on tunnel structure 2, this locating device 8 is by 6 fixed bar 8a of tunnel structure 2 inside surfaces, 6 the backstay 8b of outside surface and the connection cross bar 8c on tunnel structure 2 upper and lower surfaces form, and fixed bar 8a is connected with backstay 8b and is fixed on the tunnel structure 2 by connecting cross bar 8c; The inside surface of backstay 8b is provided with 8 anchor cable locating slots with hoop anchor cable 5 form fit, and every hoop anchor cable 5 places in the corresponding anchor cable locating slot.

B, pad are established the antifriction layer and are filled up between tunnel structure 2 and hoop anchor cable 5 and establish the teflon antifriction layer 7 that radian is 270 ° of circular arcs, this circular arc antifriction layer 7 is distributed between forward and backward hoop beam 3a, the 3b symmetrically, and hoop Liang3aChu rose to its end and only was divided into 3 sections that friction factor successively decreases 7 the past of antifriction layer.

When pad is established the antifriction layer, antifriction layer 7 hoop Liang3aChu in the past rises and only is divided into 3 sections the concrete practice that friction factor successively decreases to the end and is: the antifriction section at place, end is made of one deck teflon piece, the antifriction layer of preceding hoop Liang3aChu is made of two-layer teflon piece, and scribble lubricant between two-layer teflon, remaining antifriction section is made of two-layer teflon piece.

The layout of C, testing tool is pasted on 126 foil gauges 10 on the inside surface and outside surface of section of jurisdiction 21, and displacement meter 11 is installed on the inside surface of tunnel structure 2, and crack gauge 12 is installed on the inside surface and outside surface of junction, tunnel structure 2 section of jurisdiction.D, test outwards eject the push rod of lifting jack 6, with 5 tensions of hoop anchor cable, tunnel structure 2 is imposed radial pressure, by foil gauge, displacement meter, crack gauge and strainometer, reinforcing bar meter the load capacity of loading and the mechanical property parameters of tunnel structure 2 are tested simultaneously, and test result is imported Computer Analysis calculate.

Analytical calculation draws according to theory of mechanics below, and the hoop anchor cable is located the relation of the suffered friction force of anchor cable to the contact pressure of shield tunnel construction outside surface with this.

Fig. 3 illustrates, and the infinitesimal d1 that gets in the hoop anchor cable 5 carries out force analysis, supposes that coefficientoffriction is constant on the little infinitesimal d1 of infinite in length.

During infinitesimal d1 stress balance in the hoop anchor cable 5:

$N_g\cos \frac{\mathrm{d\θ}}{2}-f-N_g^{\′}\cos \frac{\mathrm{d\θ}}{2}=0---\left(1\right)$

$F_c-N_g\sin \frac{\mathrm{d\θ}}{2}-N_g^{\′}\sin \frac{\mathrm{d\θ}}{2}=0---\left(2\right)$

Wherein, N _gBe the suffered anticlockwise stretching force of anchor cable 5 infinitesimal d1, N _g' be the suffered clockwise stretching force of infinitesimal d1, f is the suffered stiction of infinitesimal d1, F _cThe normal direction contact pressure that is applied for the suffered tunnel structure 2 of infinitesimal d1.

Because stiction f evenly distributes on d1, then:

f＝μF _c (3)

Fig. 4 illustrates, and according to acting force and reacting force principle, acts on the normal direction contact pressure F on the tunnel structure 2 infinitesimal dL _ωFor:

F _ω＝-F _c (4)

By (1), (2), (3), (4) Shi Kede, the normal direction contact pressure F that the infinitesimal dL of shield tunnel construction 2 is suffered _ωFor:

$F_{\mathrm{\ω}}=\frac{N_g\sin \mathrm{d\θ}}{\mathrm{\μ}\sin \frac{\mathrm{d\θ}}{2}+\cos \frac{\mathrm{d\θ}}{2}}---\left(5\right)$

Because

Be an a small amount of, so have $\sin \frac{\mathrm{d\θ}}{2}\≈\frac{\mathrm{d\θ}}{2},$ $\cos \frac{\mathrm{d\θ}}{2}\≈1,$ Substitution (5 formulas are reduced to:

$F_{\mathrm{\ω}}=\frac{2N_g\mathrm{d\θ}}{\mathrm{\μd\θ}+2}---\left(6\right)$

Can learn the contact pressure of 5 pairs of shield tunnel construction 2 outside surfaces of hoop anchor cable everywhere, the negative correlativing relation that is inversely proportional to the suffered friction force of this place's anchor cable 5 by (6) formula.Therefore can pass through to lay antifriction layer 7, and make the friction factor difference of antifriction layer 7 each section, the frictional resistance that changes hoop anchor cable 5 and tunnel structure 2 outside surfaces is to change the contact pressure F of 5 pairs of tunnel structures 2 of hoop anchor cable _ω, can apply the pressure that a kind of " bulb-shaped " distributes to tunnel structure 2, simulate the pressure of the non-uniform Distribution of shield tunnel construction 2.Thereby simulate the role and influence of true hydraulic pressure to tunnel structure.

Fig. 2 is the pressure-plotting that uses the resulting tunnel structure of the inventive method, and arrow length is wherein represented this place force value, and it is the bulb-shaped distribution, and the distribution of the true hydraulic pressure that is born to submerged tunnel structure 2 is similar.

Obviously, the quantity of hoop anchor cable 5 of the present invention, locating device 8, foil gauge 10, displacement meter 11, crack gauge 12 and strainometer, reinforcing bar meter is not limited to the quantity of embodiment; The radian of circular arc antifriction layer 7 and the hop count of antifriction layer 7 also are not limited to the situation of embodiment, and can be the circular arc antifriction layers 7 that is divided into 250-290 ° of radian of 3-5 section.

Claims (3)

1. the hydraulic pressure prototype test method of a underwater shield tunneling structure, its practice is:

The duct pieces of shield tunnel (21) that A, installation hoop anchor cable will be embedded with strainometer, reinforcing bar meter is assembled into short cylinder shape tunnel structure (2), then described tunnel structure (2) is placed ground, and wherein axis normal is in ground; Vertical former and later two hoop beams (3a, 3b) are arranged at the outside surface of described tunnel structure (2) symmetrically, the hoop anchor cable (5) of the vertical band loadometer more than two that distributes alternately is anchored on the forward and backward hoop beam (3a, 3b), and hoop anchor cable (5) then is fixed on around the other end of described tunnel structure (2) after the surperficial week on the push rod of lifting jack (6) of corresponding hoop beam (3a, 3b);

B, pad are established the antifriction layer and are filled up between described tunnel structure (2) and hoop anchor cable (5) and establish the teflon antifriction layer (7) that radian is a 250-290 ° of circular arc, this circular arc antifriction layer (7) is distributed between the forward and backward hoop beam (3a, 3b) symmetrically, and the part of described antifriction layer (7) hoop beam (3a) before be positioned to the both ends of described antifriction layer (7) only respectively are divided into the 3-5 section that friction factor successively decreases;

The layout of C, testing tool is pasted on a plurality of foil gauges (10) on the inside surface and outside surface of described section of jurisdiction (21), crack gauge (12) is installed on the inside surface and outside surface of junction, described section of jurisdiction (21), and displacement meter (11) is installed on the inside surface of described tunnel structure (2);

D, test outwards eject the push rod of lifting jack (6), hoop anchor cable (5) is strained, described tunnel structure (2) is imposed radial pressure, by foil gauge (10), displacement meter (11), crack gauge (12) and strainometer, reinforcing bar meter the load capacity of loading and the mechanical property parameters of described tunnel structure (2) are tested simultaneously, and test data is imported Computer Analysis calculate, obtain test result.

2. the hydraulic pressure prototype test method of a kind of underwater shield tunneling structure according to claim 1, it is characterized in that: the described A step is when installing the hoop anchor cable, anchor cable locating device (8) also is set on described tunnel structure (2), this locating device (8) is by the fixed bar (8a) of described tunnel structure (2) inside surface, the connection cross bar (8c) on backstay of outside surface (8b) and the upper and lower surface of described tunnel structure (2) is formed, and fixed bar (8a) is connected with backstay (8b) and is fixed on the described tunnel structure (2) by connecting cross bar (8c); The inside surface of backstay (8b) is provided with the anchor cable locating slot with the quantity and the form fit of hoop anchor cable (5), and every hoop anchor cable (5) places in the corresponding anchor cable locating slot.

3. the hydraulic pressure prototype test method of a kind of underwater shield tunneling structure according to claim 1, it is characterized in that: the described B step fills up when establishing the antifriction layer, the concrete practice that the part of described antifriction layer (7) hoop beam (3a) before be positioned to the both ends of described antifriction layer (7) respectively are divided into the 3-5 section that friction factor successively decreases with onlying is: the antifriction section that both ends are located is made of one deck teflon piece, the antifriction layer that preceding hoop beam (3a) is located is made of two-layer teflon piece, and scribble lubricant between two-layer teflon, remaining antifriction section is made of two-layer teflon piece.

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