Background technology
Geostatic stress is meant the inherent strain of rock mass under native state.When the tunnel vertically passes geostatic stress weak surrounding rock stratum, if the uniaxial compressive strength (R of country rock
b) and major principal stress (σ
H, max) ratio, i.e. R
b/ σ
H, maxIn the time of in 4~7 scopes, be called high-ground stress; Work as R
b/ σ
H, max, be called stress highly at<4 o'clock.
In the constructing tunnel process, need in advance to confirm at every turn tap length longitudinally, be about to whole tunnel and be divided into multistage tunnel passage and excavate in order according to the concrete condition of rock mass; When construction, excavate first section tunnel passage according to this tap length earlier, in this first section tunnel passage, implement supporting then; After the completion; Can continue from the end of first section tunnel passage longitudinally to excavate second section tunnel passage, on second section tunnel passage, implement supporting, after the completion; Longitudinally excavate the 3rd section tunnel passage at the end of second section tunnel passage again; So circulation is gone down, and behind the supporting construction of accomplishing final stage tunnel passage, multistage tunnel passage has just formed a complete tunnel.
Wherein, The tunnel support operation is the construction in order to prevent that the tunnel from must in time carry out after excavating every section tunnel passage caving in behind the excavation; And the design of support process has only the concrete geological conditions with this rock stratum, place to adapt, and just can play good resistance to deformation, anti-effect of caving in.But, in the prior art, at high-ground stress even highly under the stress soft rock stress layer geological conditions during excavation tunnel, adopted be with common geostatic stress rock stratum condition under identical support process, be specially:
A Pin rigidity preliminary bracing is set up on the surface of step 1, closely connected tunnel passage; Detailed process be adopt the arch profile steel frame identical with the section configuration of tunnel channel surface from the medial support tunnel passage, that is, the peripheral surface of the outer rim of arch profile steel frame and tunnel passage fits tightly, and then on the arch steelframe sprayed mortar.
Step 2, implement secondary lining based on above-mentioned rigidity preliminary bracing; That is, execute in rigidity preliminary bracing inboard and to do the form concrete lining cutting, to form level and smooth tunnel surface similar with the tunnel channel shape and the passage longitudinal extension along the tunnel.
Support process of the prior art adopts direct closely connected tunnel channel surface to set up the mode of rigidity preliminary bracing; Make under the high stress in the peripheral rock stratum of tunnel passage; Often cause concrete cracking in the preliminary bracing, peel off, and arch profile steel frame torsional deformation; The distortion of arch profile steel frame can be occupied the space of next step secondary lining, causes and can't continue to implement secondary lining, thereby the rigidity preliminary bracing of having built of having to dismantle, rebulid new rigidity preliminary bracing; Engineering cost and construction risk are significantly increased.
Summary of the invention
To above-mentioned defective of the prior art; The present invention provides a kind of tunnel supporting method, tunnel support structure and tunnel; Avoid the high-ground stress of country rock to cause preliminary bracing to peel off, be out of shape the space that ties up secondary lining; Thereby realize need not to rebuild preliminary bracing, guarantee carrying out smoothly of constructing tunnel, this method is particularly useful for the constructing tunnel of high ground stress soft rock stress layer.
First aspect of the present invention provides a kind of tunnel supporting method, comprising:
The peripheral surface of step 1, the closely connected tunnel passage of having excavated is set up the flexible support that at least one Pin is used to support said tunnel passage; And in said tunnel the channel surface sprayed mortar, with the common flexible support layer that is covered in said tunnel channel surface that forms of at least one said flexible support;
Step 2, set up the preliminary bracing of at least one Pin rigidity in said flexible support layer inboard; Leading flank and/or trailing flank sprayed mortar in said rigidity preliminary bracing; Prop up sheath to form rigidity jointly, and said rigidity is propped up between sheath and the said flexible support layer form prepsetting gap with said rigidity preliminary bracing;
Step 3, leave standstill first deformation time;
Step 4, prop up sheath based on said rigidity and build secondary lining.
Preferably, before said step 4, also comprise:
The prepsetting gap that said flexible support layer and said rigidity are propped up between the sheath carries out the slip casting backfill.
Second aspect of the present invention provides a kind of tunnel support structure, comprising:
Cover the flexible support layer of the peripheral surface of the tunnel passage of having excavated, said flexible support layer by at least one Pin, closely connected in said tunnel the flexible support and the concrete coating of the peripheral surface of passage form;
Be arranged on said flexible support layer rigidity inboard, that be formed with prepsetting gap with said flexible support and prop up sheath, said rigidity is propped up sheath by the preliminary bracing of at least one Pin rigidity and be formed on said rigidity preliminary bracing front side and the layer of concrete back-up coat of/rear side is formed;
The surface of propping up sheath in said rigidity is set with secondary lining, and said secondary lining shape of cross section and said rigidity preliminary bracing are complementary and extend longitudinally.
Preferably, in above-mentioned tunnel support structure, also comprise:
Be filled in said flexible support layer and rigidity and prop up the cement paste layer in the prepsetting gap between the sheath.
Another aspect of the present invention provides a kind of tunnel, comprising: the tunnel passages together, more than two sections that are linked in sequence from beginning to end, the inboard of every section said tunnel passage is provided with as above arbitrary described tunnel support structure.
Tunnel supporting method provided by the invention, tunnel support structure and tunnel; Through setting up the mode that flexible support layer and rigidity are propped up sheath and formed prepsetting gap respectively; Can allow country rock to produce certain deformation, thereby the high-ground stress in the country rock obtain discharging, and has reduced the stressed of rigidity preliminary bracing; Thereby; Guaranteed that the rigidity preliminary bracing can not be out of shape, avoided occupying the operation that the secondary lining space must rebuild the rigidity preliminary bracing, reduced construction cost and construction risk because of the rigidity preliminary bracing.
The specific embodiment
" vertically " described in the present invention is meant the direction that the tunnel passage extends, and a plurality of tunnels passage longitudinally head and the tail is connected to form the tunnel, certainly, the tunnel can be straight, also can bend; " preceding " is meant that the tunnel is with carrying out of excavating and the direction that advances; Arbitrary cross section of tunnel passage and tunnel channel surface intersect and the curve that obtains is circumferential curve; A plurality of circumferential curves parallel to each other are longitudinally arranged " peripheral surface " that forms the tunnel passage, and a plurality of " peripheral surface " are longitudinally arranged the whole surface of formation " tunnel passage ".
In order to understand technical scheme of the present invention better, at first the tunnel construction process is simply described.Before the tunnel construction engineering construction; The major parameter and the equipment needed thereby of meeting clear and definite engineering construction in scheme design process; Comprising; Confirm the shape and the size of excavation outline line of length and number, the tunnel passage of the length overall in tunnel, every section tunnel passage, and Pin spacing (adjacent two supporting positions along the tunnel distance) longitudinally etc.In the whole construction course in tunnel; Can adopt constructure scheme in order; Excavate one section both tunnel passage of measured length earlier; On this tunnel passage, accomplish the supporting construction step in order, and then carry out the excavation and the supporting of next section tunnel passage, so continue to always and accomplish both tunnel passages of determined number based on this section tunnel passage.Require the construction period very in short-term in addition, can adopt parallel constructure scheme, promptly; After excavating first section tunnel passage, on this first section tunnel passage, implement in the supporting construction step, also the end at this first section tunnel passage continues to excavate second section tunnel passage; To be excavated go out second section tunnel passage after, on this second section tunnel passage, implement the supporting construction step again, and simultaneously; Also carry out the excavation construction of the 3rd section tunnel passage; So continue, carry out when realizing excavating, to improve efficiency of construction with supporting.Though in parallel constructure scheme; What in the different tunnels of synchronization passage, carry out is the different step of excavation and supporting; But; With regard to a certain tunnel passage, the supporting operation in the implementation process of its supporting operation and the constructure scheme in order in the tunnel passage is the same, and the present invention is primarily aimed at the improvement technical scheme that supporting operation implementation step is proposed.
Fig. 1 is the flow chart of tunnel supporting method embodiment of the present invention; One embodiment of the invention provides a kind of method for tunnel construction, please with reference to Fig. 1, comprising:
Step 201, please with reference to Fig. 2 and Fig. 3; The peripheral surface of the closely connected tunnel passage of having excavated 20 is set up the flexible support 21 that at least one Pin is used to support tunnel passage 20; And in the tunnel passage 20 jet surface concrete, with at least one flexible support 21 common flexible support layers that are covered in tunnel passage 20 surfaces that form.Promptly; Longitudinally excavate the tunnel passage 20 of both measured lengths according to pre-designed excavation outline line after; In time any in tunnel passage 20 or two above cross-section parallel to each other are set up flexible support 21 respectively, and make the outside of flexible support 21 fit tightly and be supported on the surface of tunnel passage 20; Wherein, The shape of flexible support 21 can be identical with tunnel passage 20, so that flexible support 21 is tightr with the applying of tunnel passage 20, and flexible support 21 length longitudinally can be 10~30 (mm).
After setting flexible support 21; Can be between flexible support 21 or flexible support 21 before or after the tunnel passage 20 jet surface concrete of side; The thickness of the concrete coating that forms can equate with the thickness of flexible support 21; Like this concrete coating be arranged at therebetween flexible support 21 and form the flexible support layer of condition of equivalent thickness, this flexible support layer covers the surface of whole tunnel passage 20.Certainly, the thickness of sprayed mortar also can might not require identical with the thickness of flexible support 21 for other is worth.
Step 202, please with reference to Fig. 4 a; Set up at least one Pin rigidity preliminary bracing 22 in flexible support layer inboard; Leading flank and/or trailing flank sprayed mortar in rigidity preliminary bracing 22; Prop up sheath to form rigidity jointly, and make rigidity prop up formation prepsetting gap 3 between sheath and the above-mentioned flexible support layer with the rigidity preliminary bracing.The quantity of rigidity preliminary bracing can be less than the quantity of flexible support 21 in this section tunnel passage 20, and the position need be not corresponding one by one with flexible support 21 yet, but needs to guarantee earlier to form between rigidity preliminary bracing 22 and the flexible support layer prepsetting gap 3; Preferably, rigidity preliminary bracing 22 can be arranged in a certain cross section between adjacent two flexible supports 21; Particularly, the shape of flexible support 21 and rigidity preliminary bracing 22 can be identical, and as all being arch, its length longitudinally can be more than or equal to flexible support 21 length longitudinally; And can be between the rigidity preliminary bracing 22 and be positioned at the leading flank or the trailing flank (when the preliminary bracing of many Pin rigidity is set) of rigidity preliminary bracing 22 of initiating terminal or the end of tunnel passage 20; Or sprayed mortar (when a Pin rigidity preliminary bracing only is set) on the leading flank of a Pin rigidity preliminary bracing 22 and the trailing flank, so that being connected to form rigidity through the concrete strengthening layer, all rigidity preliminary bracings 22 prop up sheath.Wherein, the thickness that sprays the concrete strengthening layer that forms can be identical with rigidity preliminary bracing 22, and like this, when the surface of flexible support layer was smooth surface, rigidity is propped up the prepsetting gap 3 that forms between sheath and the flexible support layer can be the gap of even uniform thickness; Certainly, the concrete strengthening layer that rigidity is propped up in the sheath can be different with the thickness of rigidity preliminary bracing 22, then form uneven prepsetting gap 3.Preferably, general high stressed soft rock layer can be arranged on prepsetting gap 3 in the scope of 30cm~50cm.
Among the present invention program, it is with respect to the rigidity preliminary bracing that said flexible support is construed as, and has less rigidity.Concrete structure as for flexible support and rigidity preliminary bracing then all can directly adopt supporting and protection structure commonly used in this area; For example; Flexible support 21 can adopt the grid steelframe with better flexibility in the present embodiment, can obtain different rigidity through the selection of grid steelframe and the concrete ratio of being sprayed; The rigidity preliminary bracing can be the relatively large steel frame construction of any rigidity; The steelframe processed of shaped steel (adopting the H175 steelframe in the present embodiment) for example; Certainly, wood materials also capable of using or other organic material are processed the arch support that the cross-sectional profiles with tunnel passage 20 is complementary and are used as flexible support 21; The steelframe that rigidity preliminary bracing 22 can adopt shaped steel to process, as long as have the rigidity difference between the two, the present invention does not do special qualification to this.
Step 203, leave standstill first deformation time; In the process of first deformation time that after having set up rigidity preliminary bracing 22, has left standstill, the high-ground stress in the country rock 11 can be oppressed flexible support 21, makes country rock 11 be out of shape in prepsetting gap 3 with flexible support 21, occupies part prepsetting gap 3.Rigidity preliminary bracing 22 has just been set up prepsetting gap 3 after finishing shown in Fig. 4 a, treats that the metaboly of being illustrated like Fig. 4 b might take place for prepsetting gap 3 after first deformation time in the past.
Step 204, please with reference to Fig. 5, prop up sheath based on rigidity and build secondary lining 23.That is, prop up the inner surface of sheath in rigidity and implement the form concrete lining cutting,, also reached the surface smoothing that makes the tunnel passage, effect attractive in appearance simultaneously to form one section complete tunnel passage.
The tunnel supporting method that present embodiment provides through setting up the mode that flexible support layer and rigidity are propped up sheath and formed prepsetting gap respectively, can allow country rock to produce certain deformation; Thereby the high-ground stress in the country rock obtains discharging; Reduced the stressed of rigidity preliminary bracing, thereby, guaranteed that the rigidity preliminary bracing can not be out of shape; Avoided occupying the operation that the secondary lining space must rebuild the rigidity preliminary bracing, reduced construction cost and construction risk because of the rigidity preliminary bracing; Especially be beneficial to the safety and the efficient of raising at the constructing tunnel in area, high-ground stress rock stratum.
Can know by step 1 in the foregoing description, a Pin, two Pin or more Pin flexible supports 21 can be set in the same section tunnel passage 20.It is specifically set up process and can adopt and once excavate tunnel passage 20, in tunnel passage 20, sets up a Pin or many Pin flexible support then successively; But; When tunnel passage 20 is long, when its domestic demand is provided with a plurality of flexible support 21, when especially geological conditions is more weaker, so once excavates one section tunnel passage 20 growing and just possibly cause subsiding in the mining process; For thoroughly eliminating this potential hidden danger of subsiding; Can adopt one section tunnel passage 20 further is divided into a plurality of segmentations, only excavate the scheme of one section segmentation of tunnel passage 20 at every turn, be elaborated in the face of this scheme down.
In the foregoing description; The peripheral surface of the closely connected tunnel passage of having excavated 20 set up at least one Pin be used to support tunnel passage 20 flexible support process can for; The peripheral surface of the closely connected tunnel passage of having excavated 20 is set up the flexible support 21 that at least three Pin are used to support tunnel passage 20; Particularly, its process can for:
Longitudinally excavate first section segmentation of tunnel passage 20, the peripheral surface of first section segmentation of closely connected tunnel passage 20 is set up a Pin flexible support 21;
End based on first section segmentation of tunnel passage 20 repeats said process, and up to the final stage segmentation of having excavated tunnel passage 20, and the peripheral surface of the final stage segmentation of closely connected tunnel passage 20 is set up a Pin flexible support 21.
This programme is through being divided into the tunnel passage a plurality of segmentations, each mode of a segmentation of only excavating; Significantly reduced each tap length longitudinally; Can form simultaneously the structure that many Pin flexible support is set in the same section tunnel passage, the safety that has further improved this tunnel supporting method again.
Please, before accomplishing secondary lining 23 steps, also comprise based on rigidity preliminary bracing 22 with reference to Fig. 4 c and Fig. 5:
The prepsetting gap 3 that flexible support layer and rigidity are propped up between the sheath carries out the slip casting backfill, promptly fills the space that is tied up by flexible support 21 distortion as yet in the prepsetting gap 3 with cement paste.Wherein, the water/binder ratio of cement paste can be selected in the scope at 0.6: 1~0.8: 1, and grouting pressure can be selected in 0.1~0.2MP scope; In addition, also can in this cement paste, add accelerating admixture, so that setting time is controlled within an hour.
Can make flexible support and rigidity preliminary bracing be integrally formed structure through the slip casting backfill, thereby reach better supporting effect.
Another embodiment of the present invention provides a kind of tunnel support structure, please with reference to Fig. 4 a, Fig. 5 and Fig. 6, comprising:
Cover the flexible support layer of the peripheral surface of the tunnel passage of having excavated 20, this flexible support layer by at least one Pin, closely connected in the tunnel flexible support 21 and the concrete coating 212 of the peripheral surface of passage 20 form; Preferably, the flexible support layer can comprise flexible support 21 at least three Pin, vertical arrangement of passage 20 along the tunnel;
Be arranged on flexible support layer rigidity inboard, that be formed with prepsetting gap 3 with this flexible support layer and prop up sheath, this rigidity is propped up sheath and is made up of at least one Pin rigidity preliminary bracing 22 and the concrete strengthening layer 222 that is formed on rigidity preliminary bracing 22 front sides and/or rear side; When the rigidity of tunnel passage 20 is propped up when including only a Pin rigidity preliminary bracing 22 in the sheath; The front side of rigidity preliminary bracing 22 and rear side can be concrete strengthening layer 222; When rigidity is propped up sheath and is comprised three above rigidity preliminary bracings 22; Can connect through concrete strengthening layer 222 between the adjacent rigidity preliminary bracing 22, in also can be concrete strengthening layer 22 with the front side and the rear side of the rigidity preliminary bracing of least significant end foremost.
The surface of propping up sheath in rigidity is set with secondary lining 23, and the shape of cross section of secondary lining 23 and rigidity are propped up sheath and be complementary and extend longitudinally.
In the present embodiment, the shape of cross section of tunnel passage 20 can be square, polygon or arch; The shape of the shape of tunnel passage 20 and flexible support 21 can be identical, so that both better fit tightly, prevents that the detritus particle on the country rock 11 is scattered; Rigidity preliminary bracing 22 can be identical or different with flexible support 21; Preferably; Flexible support 21 is the same with the shape of cross section of tunnel passage 20 with rigidity preliminary bracing 22; All be the identical arch of radian, and the rigidity of flexible support 21 is less than rigidity preliminary bracing 22, to guarantee that flexible support 21 can produce distortion to discharge geostatic stress under the high-ground stress effect in country rock 11; But rigidity preliminary bracing 22 can be out of shape, not tie up the space of secondary lining.In the specific implementation, the arch support that flexible support 21 can adopt wood materials to process, or the arch steelframe that combines of the softer reinforcing bar of quality preferably, can adopt grid steelframe commonly used in this area; The higher profile steel frame of excellent rigidity is then generally selected in rigidity preliminary bracing 22, the profile steel frame that for example can adopt H175 to produce, and can be on this profile steel frame sprayed mortar.
The tunnel support structure of present embodiment; Because the prepsetting gap 3 that flexible support layer and rigidity are propped up between the sheath can be for flexible support provides deformation space, thereby reached through country rock together with the common distortion of flexible support, avoided the high-ground stress of country rock to cause the rigidity preliminary bracing to be out of shape to discharge the purpose of the high-ground stress in the country rock as far as possible; Guaranteed the secondary lining smooth implementation; Reduced engineering cost, and compared with prior art, this supporting and protection structure is more reliable and more stable, risk is lower.
Further, as shown in Figure 5, also comprise in the above-mentioned tunnel support structure:
Be filled in flexible support layer and rigidity and prop up the cement paste layer 31 in the prepsetting gap 3 between the sheath.This cement paste layer 31 can make flexible support layer and rigidity prop up sheath and form more stable whole, so that supporting and protection structure plays a role better.
Further embodiment of this invention provides a kind of tunnel, please with reference to Fig. 4 a and Fig. 5, comprising: the tunnel passages 20 together, more than two sections that are linked in sequence from beginning to end, the inboard of every section tunnel passage 20 is provided with the tunnel support structure among above-mentioned arbitrary embodiment.The concrete structure of tunnel support structure is similar to the above embodiments, repeats no more at this.
In addition, in the present invention, each segmentation of tunnel passage, tunnel passage, flexible support and rigidity preliminary bracing length longitudinally all can be come through calculating definite according to concrete operating mode; And above-mentioned parameter capable of using further calculates and confirms the Pin spacing, and the quantity of flexible support, rigidity supporting.The Pin spacing is meant two adjacent Pin flexible supports or the distance between the rigidity preliminary bracing, and the occurrence of Pin spacing can be the leading flank of two adjacent flexible supports (rigidity preliminary bracing) or the distance between the trailing flank; In whole tunnel, the Pin spacing of flexible support or rigidity preliminary bracing can be definite value, and promptly flexible support or rigidity preliminary bracing are for being spacedly distributed; Certainly, also can be because of the particularity of concrete geological condition, be provided with variant with respect to the position of the tunnel passage at place the flexible support in the different tunnels passage 20 and/or rigidity supporting; Like this; Then each is unequal for the Pin spacing, but which kind of situation no matter, the tunnel support structure that all can adopt present embodiment to provide.
The tunnel that present embodiment provides; Through the flexible support layer is set, rigidity is propped up sheath; And make the mode that forms prepsetting gap between the two, and make flexible support can produce distortion to discharge the high-ground stress in the country rock 11, reduced the stressed of rigidity preliminary bracing; Avoided being out of shape the situation of rebuilding of to dismantle and taken place, can reduce construction cost because of the rigidity preliminary bracing; In addition, adopt the tunnel of this supporting and protection structure to have better stability, safety is higher.
What should explain at last is: above each embodiment is only in order to explaining technical scheme of the present invention, but not to its restriction; Although the present invention has been carried out detailed explanation with reference to aforementioned each embodiment; Those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, perhaps to wherein part or all technical characteristic are equal to replacement; And these are revised or replacement, do not make the scope of the essence disengaging various embodiments of the present invention technical scheme of relevant art scheme.