CN113803092B - Supporting device and method for broken soft rock roadway based on steel pipe concrete support - Google Patents
Supporting device and method for broken soft rock roadway based on steel pipe concrete support Download PDFInfo
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/021—Grouting with inorganic components, e.g. cement
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/107—Reinforcing elements therefor; Holders for the reinforcing elements
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
- E21D11/152—Laggings made of grids or nettings
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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- Life Sciences & Earth Sciences (AREA)
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- Geochemistry & Mineralogy (AREA)
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Abstract
The invention discloses a supporting device and a method for a broken soft rock roadway based on a steel tube concrete bracket, and relates to the technical field of ground ores. The method comprises the following steps: firstly, placing a plurality of hollow grouting anchor rods into surrounding rocks of a roadway, and performing advanced grouting reinforcement support; then spraying concrete on the surrounding rock of the roadway to form a concrete layer, and crushing the rock on the surface of the roadway through the concrete layer to form a whole; then erecting a bending-resistant early-strength steel tube concrete bracket structure at a certain distance from the plastic plate; pouring early-strength concrete into the bracket, arranging bending steel bars in the circumferential direction of an outer roadway of the bracket, and constructing a bending-resistant early-strength reinforced concrete arch body with a certain thickness between the plastic plate and the bending steel bars; and finally, arranging a plastic plate yielding layer between the surrounding rock of the roadway and the bending-resistant early-strength reinforced concrete arch body. The invention can effectively control the deformation of surrounding rock by combining the ultra-strong grouting reinforcement technology with the bending-resistant steel pipe concrete support structure, and has good supporting effect.
Description
Technical Field
The invention relates to the technical field of ground mines, in particular to a supporting device and a method for a broken soft rock roadway based on a concrete filled steel tube bracket.
Background
As the mining of modern coal mines extends deeper, the geological conditions of the mine become more complex. Soft rock is one of them, and the problem of supporting soft rock roadways is also emphasized. Research shows that the deep soft rock roadway is affected by the factors such as the direction of a ground stress field, the formation occurrence, the dissymmetry of a rock mass structure, the differential deformation of key parts and the like, and the deep soft rock roadway is subjected to the dissymmetry deformation due to the structural effect, so that the conventional symmetrical support cannot be controlled, the self-supporting capacity of the roadway surrounding rock is weak, the roadway deformation speed and the deformation amount are large, and the mine production is greatly affected. In the aspect of soft rock roadway support, the prior art has not reached the requirement of mine production due to the reasons of technology, capital investment and the like.
The soft rock roadway is characterized in that:
(1) Due to the rock mass structure and the environment of the rock stratum, the rock stratum is soft, seriously crushed and has higher ground stress; (2) The physical and mechanical properties of the rock mass are characterized by low strength, rheology, weathering, expansion and the like; (3) For engineering characteristics of surrounding rock, the roadway compression is strong, and surrounding rock deformation has the characteristics of surrounding compression and obvious time effect; (4) The initial pressure is fast, the deformation amount is large, the surrounding rock is still continuously and largely deformed at a certain speed for a long time after the surrounding rock is stabilized, and the stability of the surrounding rock is difficult to control. Namely: weak rock stratum roadway has the characteristics of loose, scattered, soft and weak. The prior researches show that the rock mass and the rock stratum structural surface are main reasons for causing the strength reduction of surrounding rock of a roadway and the generation of asymmetric large denaturation damage, and the control of the structural surface is key to the asymmetric support design, thereby providing a basis for the control of a soft rock roadway.
Due to the characteristics of the soft rock roadway, the soft rock roadway also has certain difficulty in supporting. At present, in the aspect of soft rock roadway support, the prior art forms a series of anchor spraying, anchor net spraying, prestress anchor cable support, a steel frame support, reinforced concrete support, a stone arch support and a series of grouting reinforcement and pressure relief support. Related studies of the prior art report mainly:
application number 202011539713.7 discloses a supporting method of a soft rock roadway, which utilizes numerical simulation software to establish model analysis and develop real-time roadway surrounding rock deep displacement monitoring and loose coil analysis, and analyzes stress distribution and convergence displacement of two sides of an asymmetric surrounding rock roadway; the high stress area and the low stress area are supported in a partitioning way by using a supporting process of 'two digging two anchor nets and one spraying steel belt' based on a supporting principle of 'first yielding and then resisting'. The support technology comprises short anchor rods, long anchor rods, primary anchor nets, secondary anchor nets, double-layer reinforcing steel bars, sprayed concrete and the like.
The application number 202021246768.4 discloses a steel canopy of high-ground-pressure soft rock tunnel support, is connected with steel canopy leg at two bottoms on steel canopy top through U type card cable respectively, the bottom fixed connection sizing block of steel canopy leg, steel canopy leg is fixed in tunnel terrace junction and is provided with U shaped steel dog, U shaped steel sill beam is fixed in between sizing block and the U shaped steel dog in tunnel both sides, constitutes a U shaped steel canopy support whole.
Although the supporting of the soft rock roadway in the prior art is studied in many ways, the supporting effect of the soft rock roadway is still to be further improved, such as a U-shaped steel contractible bracket, an anchor-sprayed net supporting system, a totally-enclosed supporting system with contractibility or yielding devices and a composite supporting for key parts are main methods for supporting the soft rock breaking dynamic pressure roadway of the coal mine. However, how the soft rock roadway is supported depends on the selection of the supporting mode, and is also related to geological conditions, surrounding rock stress states and the like of the roadway. Therefore, many studies are required to find an effective support.
Disclosure of Invention
The invention aims to provide a supporting method of a broken soft rock roadway based on a steel pipe concrete support, which can effectively control surrounding rock deformation by combining a super grouting reinforcement technology with a bending-resistant steel pipe concrete support structure and has a good supporting effect.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a supporting method of a broken soft rock roadway based on a concrete filled steel tube bracket sequentially comprises the following steps:
a. advanced grouting reinforcement support
Placing a plurality of hollow grouting anchor rods into surrounding rocks of a roadway, taking each hollow grouting anchor rod as a grouting pipe, injecting grouting liquid into the surrounding rocks of the roadway through the grouting pipes, and reinforcing and supporting the surrounding rocks of the roadway;
the grouting liquid is a mixed liquid of silicate cement, water glass and a water reducing agent, and the mass ratio of water to ash in the silicate cement is 0.7: 1-1:1, wherein the mass of the water reducer is 0.8-1.0% of the mass of the Portland cement, and the volume of the water glass is 0.4-0.6% of the volume of the Portland cement;
b. spraying concrete on surrounding rock of the roadway to form a concrete layer, and crushing the rock on the surface of the roadway into a whole through the concrete layer;
covering the surface of the concrete layer with a plastic plate, wherein the compressive strength of the plastic plate is more than or equal to 250kPa;
c. construction of bending-resistant early-strength steel tube concrete support structure
Setting up a bending-resistant early-strength steel pipe concrete support structure at a certain distance from the plastic plate, wherein the bending-resistant early-strength steel pipe concrete support structure is formed by connecting a plurality of independent supports together, the distance between the adjacent supports is 0.6-1.0 m, each support comprises a straight wall section, an arc section, a top arc section and a reverse bottom arc section, the straight wall section and the arc section are respectively provided with two sections, the arc sections are correspondingly connected to the top end of the straight wall section, and the straight wall section, the arc section and the top arc section form an inverted U-shaped structure; the reverse bottom arch section is arranged in the bottom plate rock stratum, a grouting hole is formed in the right side of the reverse bottom arch section, and a grouting short pipe serving as a grouting nozzle is arranged outside the grouting hole;
d. pouring early-strength concrete into the bending-resistant early-strength steel pipe concrete support structure;
e. bending steel bars are arranged in the circumferential direction of an outer roadway of the bending early-strength steel tube concrete support structure, early-strength concrete made of sulfate cement is sprayed between the plastic plate and the bending steel bars, and a bending early-strength steel tube concrete arch body with a certain thickness is formed; the roadway surrounding rock is supported together through the bending-resistant early-strength steel tube concrete support structure and the bending-resistant early-strength steel reinforced concrete arch body;
f. a plastic plate yielding layer is arranged between a roadway surrounding rock and a bending-resistant early-strength reinforced concrete arch body, a wood block yielding window is reserved in the bending-resistant early-strength reinforced concrete arch body, and the early-strength bending-yielding type concrete arch body is formed.
The technical scheme directly brings the following beneficial technical effects:
aiming at the characteristic that surrounding rock of a soft rock roadway is extremely broken, advanced grouting reinforcement support is firstly carried out on the roadway, falling and large deformation are prevented after the roadway is excavated, the porous advanced grouting technology is adopted, the self strength of the surrounding rock is improved, and the early-stage stability of the roadway is controlled. Meanwhile, the grouting liquid is mixed liquid of silicate cement, water glass and a water reducing agent, and can control extremely broken surrounding rock and simultaneously achieve good supporting effect.
And further spraying a concrete layer on the surrounding rock of the roadway to enable the surface of the roadway to break the rock to form a whole, covering a layer of high-strength plastic plate on the concrete layer, and constructing a bending-resistant early-strength steel tube concrete support structure on the outer side of the plastic plate. Through designing the early strength steel pipe concrete support structure of anti-bending, the support structure, the support connection design and the connection between the supports are related to, specifically, the support structure is divided into four sections, namely a straight wall section, a circular arc section, a top arc section and a reverse bottom arc section, and the support structure is matched with a tunnel with an oval cross section, so that the support structure can be applied under the condition that the pressure around the tunnel is very large and the distribution is uneven, and can disperse the stress of surrounding rocks of the tunnel to the positions with smaller compression degree of the supports when the early strength steel pipe concrete support structure is adopted for supporting, and release the stress of the surrounding rocks in a similar compression mode, thereby relieving the concentrated stress of the steel pipe concrete support.
The roadway surrounding rock is jointly supported by the bending-resistant early-strength reinforced concrete arch body and the bending-resistant early-strength reinforced concrete arch body.
In the step a, the hollow grouting anchor rod is provided with grout outlet holes at intervals of 20 meters from the end head, and rubber plugs matched with the grout outlet holes are arranged at the grout outlet holes.
As another preferable scheme of the invention, in the step a, the section of the roadway is flat elliptic or circular; the hollow grouting anchor rod is driven into the roadway along the axis of the roadway at an inclined angle of 30 degrees.
Further preferably, in step b, the thickness of the plastic plate is 100mm.
Still preferably, in step c, the sections of the support are connected by a sleeve, the sleeve comprises an upper end steel pipe and a lower end steel pipe, and a baffle ring for preventing the sleeve from sliding downwards is arranged in the circumferential direction of the lower end steel pipe; and an exhaust hole is arranged near the center of the top of the bending-resistant early-strength steel pipe concrete support structure.
In the step c, the straight wall section is connected with the inverted bottom arch section through a footing plate flange, the footing plate flange is connected through four bolts, and bolt holes corresponding to the four bolts are symmetrically distributed on four corners of the steel plate base; one foot plate flange is welded on the straight wall section, and the other foot plate flange is welded on the inverted bottom arch section; the adjacent brackets are connected by adopting a clamping steel belt with the thickness of 20 mm.
In the step e, the early-strength concrete is prepared by adopting the mixing amount of the sulphoaluminate cement with the mass percentage of 8 percent.
The invention further aims to provide a supporting device of a broken soft rock roadway based on a concrete filled steel tube support, which comprises a super grouting reinforcement structure, a concrete structure, a bending-resistant early-strength steel tube concrete support structure, a bending-resistant early-strength steel reinforced concrete arch body structure and a plastic plate yielding layer, wherein the super grouting reinforcement structure comprises a plurality of hollow grouting anchor rods, each hollow grouting anchor rod is placed in surrounding rock of the roadway, grouting liquid is injected into the hollow grouting anchor rods, and the super grouting reinforcement structure is formed;
the concrete structure comprises a concrete layer, wherein the concrete layer is formed by spraying concrete on surrounding rocks of a roadway, and the surface of the concrete layer is covered with a plastic plate with certain strength;
the bending-resistant early-strength steel pipe concrete support structure is positioned on the outer side of the plastic plate and is formed by connecting a plurality of independent bending-resistant early-strength steel pipe concrete supports, wherein the distance between every two adjacent supports is 0.6-1.0 m, each support comprises a straight wall section, a circular arc section, a top arc section and a reverse bottom arc section, the straight wall section and the circular arc section are respectively provided with two sections, the circular arc sections are correspondingly connected to the top end of the straight wall section, and the straight wall section, the circular arc section and the top arc section form an inverted U-shaped structure; the reverse bottom arch section is arranged in the bottom plate rock stratum, a grouting hole is arranged on the right side of the reverse bottom arch section, a grouting short pipe serving as a grouting nozzle is arranged outside the grouting hole, and the grouting short pipe is positioned on the reverse bottom arch section;
the bending-resistant early-strength steel pipe concrete support structure is filled with early-strength concrete; bending steel bars are arranged in the circumferential direction of an outer roadway of the bending-resistant early-strength steel tube concrete support structure;
the bending-resistant early-strength reinforced concrete arch body is formed by spraying early-strength concrete made of sulfate cement between the plastic plate and the bending-resistant steel bar, the bending-resistant early-strength reinforced concrete support structure and the bending-resistant early-strength reinforced concrete arch body form a common support body, and surrounding rocks of a roadway are supported through the common support body;
the plastic plate yielding layer is positioned between the roadway surrounding rock and the bending-resistant early-strength reinforced concrete arch body, a wood block yielding is arranged in the bending-resistant early-strength reinforced concrete arch body, and a yielding window is reserved in the wood block yielding, so that an early-strength-bending-yielding type concrete arch body structure is formed.
Further, the thickness of the bending-resistant early-strength reinforced concrete arch body is 400mm, and a reinforced net shell is arranged in the bending-resistant early-strength reinforced concrete arch body and is used for increasing the bending resistance of the concrete arch body.
Further, the steel bar net shell is bound in the circumferential direction of the roadway at the outer side of the concrete, the steel bar net shell comprises a plurality of bending steel bars, the row spacing between the bending steel bars is 300 multiplied by 300mm, the lap joint length of the bending steel bars is 700mm, and the bending steel bars are bound by adopting wire binding lap joint.
Compared with the prior art, the invention has the following beneficial technical effects:
(1) The invention provides a supporting method of a broken soft rock roadway based on a concrete filled steel tube bracket, which comprises the steps of firstly adopting an advanced grouting reinforcement technology, placing a plurality of hollow grouting anchor rods into surrounding rocks of the roadway, injecting grouting liquid with pressure into the surrounding rocks, and adopting the cross section shape of a flat elliptic roadway; spraying a concrete layer on the surrounding rock of the roadway, and covering a layer of plastic plate with higher strength on the concrete layer; and erecting a bending-resistant early-strength steel tube concrete bracket at a certain distance from the plastic plate, arranging high-strength bending steel bars in the circumferential direction of a roadway outside the bracket, spraying early-strength concrete to form a bending-resistant early-strength steel tube concrete arch body, and arranging a wood block yielding and reserving a yielding window in the concrete arch body. The invention solves the problems that in the process of crushing extremely weak surrounding rock, the surrounding rock is crushed and is loose and soft and difficult to support, replaces the traditional related roadway support technology, and utilizes the technology innovation to realize the effects of high support resistance of the bracket, stable yielding of the surrounding rock and sealing reinforcement.
(2) In order to prevent the occurrence of falling and large deformation after the tunnel is excavated, the invention adopts the advanced grouting reinforcement technology to improve the strength of surrounding rock and control the early stability of the tunnel. Meanwhile, water glass capable of increasing the strength degree is added into the grouting liquid, and a good supporting effect can be achieved when the extremely broken surrounding rock is controlled.
(3) According to the invention, through the designed roadway with the bending-resistant early-strength steel pipe concrete support structure and the flat oval-shaped combined section, the roadway surrounding rock stress can be dispersed to other positions with smaller compression degree of the support, and the surrounding rock stress is released in a similar compression mode, so that the concentrated stress of the steel pipe concrete support is relieved.
(4) In order to adapt to overlarge bending moment generated by roadway deformation extrusion, and considering the characteristic that a steel pipe concrete tensile zone is easy to damage, the invention adopts a bending-resistant early-strength steel pipe concrete support structure to carry out bending-resistant reinforcement on the steel pipe concrete support tensile zone; round steel is adopted as a technical means of bending resistance reinforcement; the core concrete of the steel pipe concrete adopts early strength concrete, so that the hardening speed of the concrete is increased, and the unstable and damaged inward concave of the steel pipe caused by the excessively high deformation speed of surrounding rocks of a roadway is prevented.
(5) The invention adopts a bending-resistant early-strength reinforced concrete arch body structure, prevents the outer side of the concrete arch body from bending, pulling and damaging due to the deformation and extrusion action of surrounding rocks of a roadway, and increases a reinforced net shell on the outer side of the concrete arch body so as to increase the bending resistance of the concrete arch body; the early-strength concrete is adopted, so that the hardening speed of the concrete is improved, and the roadway support and surrounding rock deformation control are facilitated; in order to cope with the characteristic of large deformation of surrounding rocks of a roadway, the damage of the surrounding rocks to the arch body structure of the bending early-strength reinforced concrete is reduced, the annular deformation capacity of the arch body structure of the bending early-strength reinforced concrete is increased, namely the deformation capacity of the arch body of the concrete is increased in the annular direction of the arch body structure of the bending early-strength reinforced concrete.
(6) The invention also provides a supporting device of the broken soft rock roadway based on the steel pipe concrete support, which is beneficial to roadway support and surrounding rock deformation control by mutually matching the yielding layer through a super grouting reinforcement structure, a concrete structure, a bending-resistant early-strength steel pipe concrete support structure, a bending-resistant early-strength steel reinforced concrete arch body structure and a plastic plate.
Drawings
The invention is further described below with reference to the accompanying drawings:
FIG. 1 is a cross-sectional view of grouting surrounding rock of a roadway according to the invention;
FIG. 2 is a longitudinal cross-sectional view of grouting surrounding rock of a roadway in the invention;
FIG. 3 is a whole construction diagram of the support of the concrete filled steel tube bracket according to the present invention;
FIG. 4 is a schematic view of the structure of a grouting hole in the present invention;
FIG. 5 is a schematic view of the construction of the joint sleeve of the present invention;
FIG. 6 is a schematic view of the construction of the position of the retainer ring in the present invention;
FIG. 7 is a schematic view of a bracket steel plate base of the present invention;
FIG. 8 is a schematic view of the construction of the inverted bottom arch bracket joint of the present invention;
FIG. 9 is a schematic diagram of the operation of the grouting pipeline of the concrete pump in the present invention;
FIG. 10 is a construction scheme of the support of the early strength steel tube concrete bracket and arch body of the present invention;
FIG. 11 is a longitudinal cross-sectional view of a concrete arch of the present invention;
FIG. 12 is a horizontal sectional view of the concrete arch of the present invention;
FIG. 13 is a block diagram of a retractable wood board in accordance with the present invention;
FIG. 14 is a schematic perspective view of a roadway floor "yield window" in accordance with the present invention;
FIG. 15 is a vertical cross-sectional view of a floor "yield window" roadway in accordance with the present invention;
fig. 16 is a top view of a roadway floor "yield window" in accordance with the present invention.
Wherein, 1, bending-resistant early-strength steel tube concrete support structure; 2. bending-resistant early-strength reinforced concrete arch body; 3. pressing the wood blocks; 4. a plastic plate; 5. roadway; 6. hollow grouting anchor rod; 7. a sleeve; 8. a top arc section; 9. a straight wall section; 10. a counter-bottom arch segment; 11. grouting holes; 12. grouting short pipe; 13. a baffle ring; 14. a steel pipe; 15. a steel plate base; 16. bolt holes; 17. a concrete delivery pump; 18. a high pressure hose; 19. a floor strata; 20. bending steel bars; 21. and a reinforcing steel bar net shell.
Detailed Description
The invention provides a supporting device and a supporting method for a broken soft rock roadway based on a concrete filled steel tube bracket, and in order to make the advantages and the technical scheme of the invention clearer and more definite, the invention is described in detail below with reference to specific embodiments.
The invention relates to a supporting device of a broken soft rock roadway based on a concrete filled steel tube bracket, which comprises a super grouting reinforcement structure, a concrete structure, a bending-resistant early-strength steel tube concrete bracket structure, a bending-resistant early-strength steel reinforced concrete arch body structure and a plastic plate yielding layer;
the super grouting reinforcement structure comprises a plurality of hollow grouting anchor rods, wherein each hollow grouting anchor rod is placed in a surrounding rock of a roadway, and grouting liquid with pressure is injected into the hollow grouting anchor rods to form the super grouting reinforcement structure;
the concrete structure comprises a concrete layer which is formed by spraying concrete on surrounding rocks of a roadway, and a plastic plate with certain strength is covered on the surface of the concrete layer;
the bending-resistant early-strength steel pipe concrete support structure is positioned on the outer side of the plastic plate and is formed by connecting a plurality of independent bending-resistant early-strength steel pipe concrete supports, wherein the distance between every two adjacent supports is 0.6-1.0 m, each support comprises a straight wall section, an arc section, a top arc section and a reverse bottom arc section, the straight wall section and the arc section are respectively provided with two sections, the two sections of arc sections are correspondingly connected to the top ends of the corresponding straight wall sections, and the straight wall section, the arc section and the top arc section form an inverted U-shaped structure; the reverse bottom arch section is arranged in the bottom plate rock stratum, a grouting hole is formed in the right side of the reverse bottom arch section, a grouting short pipe serving as a grouting nozzle is arranged outside the grouting hole, and the grouting short pipe is positioned on the reverse bottom arch section;
early-strength concrete is poured into the bending-resistant early-strength steel pipe concrete support structure; bending steel bars 20 are arranged in the circumferential direction of an outer roadway of the bending-resistant early-strength steel tube concrete support structure;
the bending-resistant early-strength reinforced concrete arch body is formed by spraying early-strength concrete made of sulfate cement between a plastic plate and bending-resistant steel bars, and the bending-resistant early-strength reinforced concrete support structure and the bending-resistant early-strength reinforced concrete arch body form a common support body, so that the roadway surrounding rock is supported by the common support body;
the plastic plate yielding layer is positioned between the roadway surrounding rock and the bending-resistant early-strength reinforced concrete arch body, a wood block yielding window is reserved in the bending-resistant early-strength reinforced concrete arch body, and an early-strength bending-yielding type concrete arch body structure is formed.
The thickness of the bending-resistant early-strength reinforced concrete arch body is 400mm, and a reinforcing mesh shell is arranged in the bending-resistant early-strength reinforced concrete arch body and is used for increasing the bending resistance of the concrete arch body.
The reinforcing steel bar net shell is bound in the circumferential direction of the roadway at the outer side of the concrete, the reinforcing steel bar net shell comprises a plurality of bending steel bars, the spacing between the bending steel bars is 300 multiplied by 300mm, the lap joint length of the bending steel bars is 700mm, and the bending steel bars are bound by adopting binding wires.
The present invention will be described in detail with reference to specific examples.
Example 1:
a supporting device of broken soft rock roadway based on a concrete filled steel tube support is provided, a plurality of hollow grouting anchor rods 6 are arranged in surrounding rock of the roadway, and grouting liquid with pressure is injected into the surrounding rock by using the grouting anchor rods. The section of the roadway 5 is round or flat elliptic.
And spraying a concrete layer on the surrounding rock of the roadway (the concrete is sprayed here to break the surface of the roadway into a whole), and covering a layer of plastic plate 4 with higher strength (the compressive strength is more than 250 kPa) on the concrete layer, wherein the thickness of the plastic plate 4 is 100mm.
The bending-resistant early-strength steel tube concrete support structure 1 is erected at a certain distance (the distance is usually 50-60 mm) from the plastic plate 4. The bending-resistant early-strength steel tube concrete support structure comprises a plurality of independent supports, wherein each independent support is of a phi 194 multiplied by 10mm,45.4kg/m steel tube type and is subjected to bending resistance strengthening by adopting phi 40 high-strength round steel, the tensile strength is 600MPa, the outer side welding mode is adopted, the distance between adjacent supports is 0.6m, and the connection mode between the supports is that 20mm thick cable steel belts are adopted.
And arranging phi 25 high-strength bending steel bars 20 in the circumferential direction of a roadway outside the concrete support, and preparing early-strength concrete by using sulphoaluminate cement to prepare C30 early-strength concrete. And early-strength concrete is sprayed between the plastic plate and the bending steel bars to form a bending-resistant early-strength reinforced concrete arch body 2. The thickness of the bending-resistant early-strength reinforced concrete arch body 2 is 400mm.
Arranging a pressing wood block 3 in the concrete arch body, wherein the thickness of the wood block is 160mm; and reserving a yielding window, wherein the yielding windows are reserved on the bottom plate and the two sides of the roadway every other bracket, namely, only one third of the circumference of the section of the roadway is supported, and the lower half of the bottom plate and the two sides are intercepted to be the yielding window.
The invention discloses a broken type weak surrounding rock roadway support method based on a concrete filled steel tube bracket, which specifically comprises the following steps:
first step, advanced grouting reinforcement support
The advanced grouting reinforcement step comprises the following steps: the method comprises the steps of grouting liquid selection, grouting drilling arrangement and grouting method.
(1) Preparation of grouting liquid
The grouting liquid is silicate cement-water glass double slurry (425 #525# silicate cement) with low price, and in consideration of the defects of high sedimentation and water precipitation rate, low calculus rate and low strength of cement paste, a proper amount of water glass and a water reducing agent can be added into the silicate cement with the water cement ratio of (0.7-1): 1 to form the silicate cement-water glass double slurry (grouting liquid).
The mixing amount of the water reducer is as follows: the weight ratio of the water reducer to the cement is 0.8-1.0%, the high-efficiency naphthalene water reducer can obviously improve the fluidity of cement slurry, improve the stability of the cement slurry, has little influence on setting time, and can effectively improve the compressive strength of the cement slurry calculus body, especially the later strength.
The doping amount of the water glass is as follows: the volume ratio of the water glass to the cement is 0.4-0.6%, the water glass can obviously increase the calculus rate of the cement slurry, shorten the setting time (including initial setting and final setting), greatly influence the early strength of the cement slurry calculus body and obviously improve the early strength of the cement slurry calculus body.
(2) Arranging grouting drilling holes
The advanced grouting adopts a hollow grouting anchor rod 6, and in order to make the grouting effect better, a drilling hole needs to be added in the hollow grouting anchor rod 6 every 20cm from the end head. After drilling is finished, the drilling is plugged with rubber, so that the water pressure is not lost during drilling, the rubber can be ejected out for normal grouting due to high pressure during grouting, and the plugging degree is determined in a processing plant test. The advanced grouting anchor rod is driven in the direction of 30 degrees along the axis of the roadway. The cross section of the grouting of the surrounding rock of the roadway of the advance support is shown in fig. 1, and the longitudinal cross section of the grouting of the surrounding rock of the roadway of the advance support is shown in fig. 2.
(3) Grouting method
The advanced grouting reinforcement support technology adopts a hollow grouting anchor rod 6 as a grouting pipe to carry out advanced support and reinforcement on surrounding rock. When the deformation of surrounding rock is not stable after the tunnel is excavated, grouting liquid is used for filling and solidifying the surrounding rock, so that the broken surrounding rock is glued into a continuous reinforcing ring, a reliable force foundation is provided for the anchor rod, and meanwhile, the grouting anchor rod can play a role in suspension and extrusion.
The advanced grouting technology aims to reduce and control the convergence deformation rate after tunnel excavation.
Secondly, constructing a bending-resistant early-strength steel tube concrete support structure
And spraying a concrete layer on the surrounding rock (the concrete is sprayed here to break the surface of the roadway into a whole), covering a layer of plastic plate 4 with higher strength (the compressive strength is more than 250 kPa) on the concrete layer, wherein the thickness of the plastic plate 4 is 100mm, and erecting a bending-resistant early-strength steel tube concrete support structure 1 outside the plastic plate 4.
In order to adapt to overlarge bending moment generated by roadway deformation extrusion, the characteristics of easy damage to a steel pipe concrete tensile zone are considered, and bending resistance strengthening is carried out on the steel pipe concrete support tensile zone; round steel is adopted as a technical means of bending resistance reinforcement; the core concrete of the steel pipe concrete adopts early strength concrete, so that the hardening speed of the concrete is increased, and the unstable and damaged inward concave of the steel pipe caused by the excessively high deformation speed of surrounding rocks of a roadway is prevented.
(1) Support structure
The bending-resistant early-strength steel pipe 1 is a steel pipe model with the diameter of 194 multiplied by 10mm and the diameter of 45.4kg/m, is subjected to bending-resistant strengthening by adopting phi 40 high-strength round steel, has the tensile strength of 600MPa, and adopts an outer side welding mode. The steel pipe concrete support structure is divided into four sections: the two-section arc section is positioned at the top of the two straight wall sections, namely, the straight wall section 9, the top arc section 8, the reverse bottom arc section 10; wherein the inverted arch segments 10 are disposed in the floor strata 19 and the segments are connected by sleeves 7, the overall structure of the bracket is shown in figure 3.
The grouting holes 11 are formed in the right side of the inverted arch section 10, grouting short pipes 12 (namely grouting nozzles) are welded outside the grouting holes 11, and the side where the grouting short pipes are arranged is separated from the side where the water ditches are arranged, so that collision is avoided. Concrete is poured into the grouting holes 11, the steel pipe is vibrated by a vibrator to compact the concrete, after grouting is stable, the grouting pipeline is disassembled, and the grouting short pipe 12 is blocked by a log plug. In order to ensure that the concrete inside the steel tube is compact and the filling condition of the concrete is monitored in real time, an exhaust hole is specially reserved, and the exhaust hole is positioned at the left and right 10mm of the center of the top of the support. As shown in fig. 4.
(2) Bracket connection design
a. Connection of arc section at top of support with lower part
The arc sections of the bracket are connected by a joint sleeve 7, the sections of the steel pipes at the two ends are firstly aligned, and then the steel pipes 14 with the same radian are sleeved outside to ensure that the steel pipes at the two ends are concentrically connected; meanwhile, in order to prevent the slip of the joint sleeve 7, a baffle ring 13 is welded on the lower end steel pipe along the circumference. The joint sleeve 7 is shown in fig. 5, and the shape and position of the baffle ring 13 are shown in fig. 6.
b. Connection of support straight wall section and inverted bottom arch section
The straight wall section 9 is connected with the inverted bottom arch section 10 through footing plate flanges, the footing plate flanges are connected through four bolts, the bolt holes 16 are symmetrically distributed at four corners of the steel plate base 15, and the distances between the bolts and the bolts are 40mm. The baseboard flanges are welded on the straight wall section 9, as shown in the figure; the other sheet is welded to the inverted bottom arch segment 10 as shown in fig. 7 and 8.
Considering that the grouting pressure can be influenced by poor sealing performance at the bottom corner flange in the grouting process, a rubber pad with the thickness of 10mm is needed to be added between the upper steel plate base and the lower steel plate base. The rubber pad is processed to be the same form and size as the steel plate base 15.
c. Connection between steel pipe concrete supports
The adjacent brackets are connected by adopting a clamping steel belt with the thickness of 20mm, and the distance between the brackets is 0.6m.
Thirdly, concrete pouring construction of the reinforced concrete bracket
And (5) after the reinforced concrete support is installed, pouring concrete in the reinforced concrete support. The concrete delivery pump 17 is horizontally placed on the roadway 5 and is connected with the bracket grouting short pipe 12 through the high-pressure rubber pipe 18, and the grouting pipe of the concrete delivery pump 17 is arranged as shown in fig. 9. It should be noted that the grouting pipe spool 12 is located on the inverted arch segment 10, so that the grouting pipe spool 12 position needs to be reserved for the back-burying of the inverted arch segment 10 in the floor strata 19.
The bracket poured concrete adopts early-strength concrete, and the concrete is prepared by adopting 8% of sulphoaluminate cement mixing amount, and the proportion of the early-strength concrete is shown in table 1. The experimental test results show that the initial setting time of the concrete is about 120 minutes, the compressive strength of the early-strength concrete test block in the 8-hour age can reach 24.7MPa, and the 24-hour strength can reach 42.8MPa.
And (3) timely pouring: and each time 4 frames of brackets are installed, grouting is performed at a short distance, and the distance between a grouting pump and the brackets is shortened.
TABLE 1 design proportions and material amounts for early strength concrete
Fourth step, preparing bending-resistant early-strength reinforced concrete arch body
And phi 25 high-strength bending-resistant ribs 20 are arranged in the circumferential direction of a roadway outside the reinforced concrete support, early-strength concrete is prepared by sulphoaluminate cement, C30 early-strength concrete is prepared, the early-strength concrete is sprayed to form a bending-resistant early-strength reinforced concrete arch body, and the bending-resistant early-strength reinforced concrete support and the arch body are jointly supported, as shown in figure 10. The thickness of the bending-resistant early-strength reinforced concrete arch body is 400mm, as shown in figures 11 and 12.
The bending-resistant early-strength reinforced concrete arch body can prevent the outer side of the concrete arch body from bending and pulling to be damaged due to the deformation and extrusion effects of the surrounding rock of the roadway, and the reinforced net shell is arranged in the concrete arch body, so that the bending resistance of the concrete arch body is improved; the early-strength concrete is adopted, so that the hardening speed of the concrete is improved, and the roadway support and surrounding rock deformation control are facilitated; in order to cope with the characteristic of large deformation of surrounding rock of a roadway, the damage of the surrounding rock to the concrete arch body is reduced, the annular deformation capacity of the concrete arch body is increased, namely the deformation capacity of the concrete arch body is increased in the annular direction of the concrete arch body.
(1) Binding reinforcing steel bar net shell
In the circumferential direction of the concrete outside roadway, phi 25 bending steel bars 20 are arranged, as shown in fig. 10 and 11, the spacing is 300mm multiplied by 300mm, the lap joint length of the steel bars is 700mm, the connecting steel bars are manufactured by machining phi 10 coils, and the spacing is 600mm. The steel bars are bound by adopting binding wires, when the steel bars are bound, the row spacing between the steel bars must be controlled within the design range, and the steel bar protection layer also accords with the design and specification requirements.
(2) Stable formwork work
According to the design requirements of construction drawings and the middle and waist lines of a roadway provided by measuring staff, discharging an arch base line and two side lines of the roadway, simultaneously and stably erecting roadway wall templates from inside to outside according to the arch base line and the side lines, firstly connecting the wall templates into a whole, arranging the wall templates outside the side lines and below the arch base line, then erecting wall upright posts at joints of wallboard and fixedly connecting the wall upright posts into a whole by using palladium nails, then erecting an upper wooden brace and a lower wooden brace on each wall upright post fixed wooden wedge and firmly fixing the upper wooden brace and the lower wooden brace, finally, between the wallboard and the roadway side, arranging an upper, a middle and a lower three-layer diagonal bracing for each wall upright post to strengthen a firm wallboard, and arranging a top post between the upper wooden brace and the lower wooden brace. The ash chute and the pouring process are not displaced. And the specification and the size of the template are ensured to meet the design requirement, and after the components are firmly and reliably connected, the tunnel arch is poured and tightly sealed. And (3) pulling the concrete into a roadway casting template, casting a roadway wall part by using a compressed air type concrete conveying tank, and symmetrically vibrating and compacting.
After the concrete of the tunnel wall is poured, fixing a 150 multiplied by 150mm lifting beam on each of the upright posts of the two side walls after the concrete is initially set. According to the design requirements of middle lane, waist line and construction drawing, the arch part arch tires and templates are stably erected gradually from inside to outside, each arch tire is fixed and firmly on the lifting beam by using palladium nails, three arch tires are connected into a whole by using three sand wood poles, one end of each arch tire is abutted against the face, at least 5 diagonal braces are arranged between each arch tire and the rock side, at least 4 diagonal braces are uniformly arranged between the arch tire and the face close to one side of the face, and the tread is covered on the arch tire.
When the arch tire and the template are stabilized, the shape, the size and the position relation among the components are ensured, the assembly and the disassembly are convenient, the joint is tight, and the slurry leakage is not easy. The size of the arch tire must meet the design requirement, and each part needs to be supported firmly.
(3) The cast-in-place concrete support adopts sulphoaluminate cement to prepare early-strength concrete, and is prepared into C30 early-strength concrete
A set of concrete mixing station and a storage yard are arranged near the wellhead of the auxiliary well, a light rail and an empty roadway rail are paved below the discharge hole of the mixer, and the mixed concrete is conveyed to the underground working surface through a cage by using a 1.5 ton mine car. A compressed air type concrete conveying tank is adopted, the concrete is slipped into a roadway arch formwork through a slip pipe, two wind-driven inserted high-frequency vibrating rods are adopted for symmetrical layered vibrating, and special fixing people are used for vibrating. During construction, the slump of concrete should be kept within the designed range, and concrete stirring is strictly carried out according to the C30 concrete mixing proportion.
The concrete material is fed into the mould by adopting manual work, the concrete material is uniformly fed into the mould, the vibration is enhanced after the concrete material is fed into the mould, the positioning, the personnel fixing and the quantitative vibration are adopted, the phenomena of honeycomb, pitted surface and dog hole are prevented, the height of the mould is 500-600mm each time when the wall is built, and the mould plate and the supporting leg are firmly fixed so as to facilitate the vibration. The arch is built from inside to outside, two sides are opposite when the mould is erected, the mould is flatly placed, the width of the mould does not exceed 200mm, and the mould is sealed firstly. The embedded part fixed on the template is not omitted, the preformed hole is firmly installed, the support frame is full of the large plate during high-altitude operation, and an operator must tie a safety belt. The vibration adopts mechanical vibration (pneumatic vibration rod), and the pouring and the tamping are carried out after the mould is put into the mould. Vibrating is carried out once every 400mm, and each layer is not more than 300mm.
When the door is folded, the door is vibrated along with the closing, so that the closing compactness is ensured, and the vibrating compactness and no hole phenomenon are ensured. When the joint of two concrete sections is constructed, the sundries and floating gangue are cleaned after being washed by clear water, and then the concrete is poured.
And after the template is removed, sprinkling and curing are timely carried out. The strength of the concrete during the form removal should ensure that the surface and edges thereof are not damaged; the concrete strength meets the design requirement when the arch mold is disassembled; and removing the template after one week after pouring.
Fifth step, let-down
(1) And arranging a plastic plate yielding layer between the roadway surrounding rock and the concrete arch body, wherein the plastic plate yielding layer is arranged as shown in fig. 10. When the surrounding rock of the roadway deforms, partial pressure of the surrounding rock is released, the pressure born by the steel rod concrete support under the action of the stress of the surrounding rock is relieved, the required supporting resistance is reduced, and the stability of the roadway is enhanced.
(2) Arranging a pressing wood block in the concrete arch body, wherein the thickness of the wood block is 160mm, as shown in fig. 13; the "yielding windows" are reserved, and the "yielding windows" are reserved on the roadway bottom plate and the two sides of each bracket, namely, only one third of the circumference of the section of the roadway is supported, and the lower half of the bottom plate and the two sides are intercepted to be the "yielding windows", as shown in fig. 14-16.
(3) The arch body has yielding property: deformation joint yielding is arranged between the concrete arch body and the surrounding rock, and deformation joint yielding is arranged in the concrete arch body.
The invention adopts the super-strong grouting technology, and water glass with increased strength is injected into grouting liquid, so that good supporting effect can be achieved while controlling surrounding rock which is easy to break.
According to the invention, by combining with the super-strong grouting technology, the tunnel is designed to be elliptic in section, so that various factors such as the magnitude and the direction of the ground pressure on the tunnel are comprehensively considered, the surrounding rock stress of the steel pipe concrete support can be released in a similar yielding mode in view of the fact that the surrounding rock of the soft rock tunnel is loose and broken, the surrounding rock is low in strength and easy to generate asymmetric large deformation, the elliptic section can be applied under the condition that the surrounding pressure of the tunnel is large and the distribution is uneven, and when the bending-resistant early-strength steel pipe concrete support structure is adopted for supporting, the tunnel stress can be dispersed to other positions with smaller compression degree of the support, and the concentrated stress of the steel pipe concrete support is relieved.
The supporting device and the supporting method are particularly suitable for supporting broken surrounding rock roadways, and can achieve good supporting effects on broken surrounding rock.
The parts not described in the invention can be realized by referring to the prior art.
It should be noted that: any equivalent or obvious modifications made by those skilled in the art under the teachings of this specification shall fall within the scope of this invention.
Claims (8)
1. The supporting method of the broken soft rock roadway based on the steel pipe concrete bracket is characterized by comprising the following steps in sequence:
a. advanced grouting reinforcement support
Placing a plurality of hollow grouting anchor rods into surrounding rocks of a roadway, taking each hollow grouting anchor rod as a grouting pipe, injecting grouting liquid into the surrounding rocks of the roadway through the grouting pipes, and reinforcing and supporting the surrounding rocks of the roadway;
the grouting liquid is a mixed liquid of silicate cement, water glass and a water reducing agent, the mass ratio of water to ash in the silicate cement is 0.7:1-1:1, the mass of the water reducing agent is 0.8-1.0% of the mass of the silicate cement, and the volume of the water glass is 0.4-0.6% of the volume of the silicate cement;
b. spraying concrete on surrounding rock of the roadway to form a concrete layer, and crushing the rock on the surface of the roadway into a whole through the concrete layer;
covering the surface of the concrete layer with a plastic plate, wherein the compressive strength of the plastic plate is more than or equal to 250kPa;
c. construction of bending-resistant early-strength steel tube concrete support structure
Setting up a bending-resistant early-strength steel pipe concrete support structure at a certain distance from the plastic plate, wherein the bending-resistant early-strength steel pipe concrete support structure is formed by connecting a plurality of independent supports together, the distance between the adjacent supports is 0.6-1.0 m, each support comprises a straight wall section, an arc section, a top arc section and a reverse bottom arc section, the straight wall section and the arc section are respectively provided with two sections, the arc sections are correspondingly connected to the top end of the straight wall section, and the straight wall section, the arc section and the top arc section form an inverted U-shaped structure; the reverse bottom arch section is arranged in the bottom plate rock stratum, a grouting hole is formed in the right side of the reverse bottom arch section, and a grouting short pipe serving as a grouting nozzle is arranged outside the grouting hole;
the sections of the bracket are connected by a sleeve, the sleeve comprises an upper end steel pipe and a lower end steel pipe, and a baffle ring for preventing the sleeve from sliding downwards is arranged in the circumference direction of the lower end steel pipe; an exhaust hole is arranged near the center of the top of the bending-resistant early-strength steel tube concrete support structure;
the straight wall section is connected with the inverted bottom arch section through a footing plate flange, the footing plate flange is connected through four bolts, and bolt holes corresponding to the four bolts are symmetrically distributed on four corners of the steel plate base; one foot plate flange is welded on the straight wall section, and the other foot plate flange is welded on the inverted bottom arch section; adjacent brackets are connected by adopting a clamping steel belt with the thickness of 20 mm;
d. pouring early-strength concrete into the bending-resistant early-strength steel pipe concrete support structure;
e. bending steel bars are arranged in the circumferential direction of an outer roadway of the bending early-strength steel tube concrete support structure, early-strength concrete made of sulfate cement is sprayed between the plastic plate and the bending steel bars, and a bending early-strength steel tube concrete arch body with a certain thickness is formed; the roadway surrounding rock is supported together through the bending-resistant early-strength steel tube concrete support structure and the bending-resistant early-strength steel reinforced concrete arch body;
f. a plastic plate yielding layer is arranged between a roadway surrounding rock and a bending-resistant early-strength reinforced concrete arch body, a wood block yielding window is reserved in the bending-resistant early-strength reinforced concrete arch body, and an early-strength bending-yielding type concrete arch body is formed.
2. The method for supporting the broken type soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 1, wherein the method comprises the following steps: in the step a, grout outlet holes are formed in the hollow grouting anchor rod at intervals of 20 meters from the end head, and rubber plugs matched with the grout outlet holes are arranged at the grout outlet holes.
3. The method for supporting the broken type soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 1, wherein the method comprises the following steps: in the step a, the section of the roadway is flat elliptic or circular; the hollow grouting anchor rod is driven into the roadway along the axis of the roadway at an inclined angle of 30 degrees.
4. The method for supporting the broken type soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 1, wherein the method comprises the following steps: in step b, the thickness of the plastic plate is 100mm.
5. The method for supporting the broken type soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 1, wherein the method comprises the following steps: in the step e, the early-strength concrete is prepared by adopting the mixing amount of the sulphoaluminate cement with the mass percentage of 8 percent.
6. The utility model provides a supporting device in broken type soft rock tunnel based on steel pipe concrete support, its includes superstrong slip casting reinforced structure, concrete structure, bending-resistant early-strength shaped steel pipe concrete support structure, bending-resistant early-strength shaped steel reinforced concrete arch body and plastic slab lets the lamination, its characterized in that:
the super grouting reinforcement structure comprises a plurality of hollow grouting anchor rods, wherein each hollow grouting anchor rod is placed in surrounding rock of a roadway, grouting liquid is injected into the hollow grouting anchor rods, and the super grouting reinforcement structure is formed;
the concrete structure comprises a concrete layer, wherein the concrete layer is formed by spraying concrete on surrounding rocks of a roadway, and the surface of the concrete layer is covered with a plastic plate with certain strength;
the bending-resistant early-strength steel pipe concrete support structure is positioned on the outer side of the plastic plate and is formed by connecting a plurality of independent bending-resistant early-strength steel pipe concrete supports, wherein the distance between adjacent supports is 0.6-1.0 m, each support comprises a straight wall section, an arc section, a top arc section and a reverse bottom arc section, the straight wall section and the arc section are respectively provided with two sections, the arc sections are correspondingly connected to the top end of the straight wall section, and the straight wall section, the arc section and the top arc section form an inverted U-shaped structure; the reverse bottom arch section is arranged in the bottom plate rock stratum, a grouting hole is arranged on the right side of the reverse bottom arch section, a grouting short pipe serving as a grouting nozzle is arranged outside the grouting hole, and the grouting short pipe is positioned on the reverse bottom arch section;
the bending-resistant early-strength steel pipe concrete support structure is filled with early-strength concrete; bending steel bars are arranged in the circumferential direction of an outer roadway of the bending-resistant early-strength steel tube concrete support structure;
the bending-resistant early-strength reinforced concrete arch body is formed by spraying early-strength concrete made of sulfate cement between the plastic plate and the bending-resistant steel bar, the bending-resistant early-strength reinforced concrete support structure and the bending-resistant early-strength reinforced concrete arch body form a common support body, and surrounding rocks of a roadway are supported by the common support body;
the plastic plate yielding layer is positioned between the roadway surrounding rock and the bending-resistant early-strength reinforced concrete arch body, a wood block yielding is arranged in the bending-resistant early-strength reinforced concrete arch body, and a yielding window is reserved, so that an early-strength-bending-yielding type concrete arch body structure is formed.
7. The supporting device for the broken soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 6, wherein: the thickness of the bending-resistant early-strength reinforced concrete arch body is 400mm, a reinforced net shell is arranged in the bending-resistant early-strength reinforced concrete arch body, and the reinforced net shell is used for increasing the bending resistance of the concrete arch body.
8. The supporting device for the broken soft rock roadway based on the concrete filled steel tube bracket as claimed in claim 7, wherein: the reinforcing steel bar net shell is bound in the circumferential direction of a roadway on the outer side of concrete, the reinforcing steel bar net shell comprises a plurality of bending steel bars, the spacing between the bending steel bars is 300 multiplied by 300mm, the lap joint length of the bending steel bars is 700mm, and the bending steel bars are bound by adopting binding wires.
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| CN112196596B (en) * | 2020-10-15 | 2022-04-29 | 山东科技大学 | Grouting anchor rod cable combination beam for advanced support of deep broken surrounding rock and support method |
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| CN101130942A (en) * | 2007-09-06 | 2008-02-27 | 长业建设集团有限公司 | Soft-ground multi-cell twin-cantilever arched bridge structure and its construction method |
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