CN213980822U - U-shaped support device for roadway - Google Patents

Abstract

The utility model relates to a tunnel U type support device. The support leg expansion device comprises support arch crown U-shaped steel, wherein two ends of the support arch crown U-shaped steel are fixedly connected with support leg U-shaped steel through connecting clamp cables, and a support leg expansion device is arranged at the bottom of the support leg U-shaped steel; the stent leg expansion device comprises a lower inner sleeve, an upper outer sleeve, a bunched composite expansion material cartridge and filled river sand; the upper outer sleeve is sleeved outside the lower inner sleeve, a bunched composite expansion material cartridge is arranged in the lower inner sleeve, and river sand is filled in the top and the bottom of the bunched composite expansion material cartridge. The utility model discloses can effectively improve the whole stress state of U type support to can provide the controllable initial holding power of load to the country rock, have and warp the adaptive function with the country rock, the column leg structure bending resistance can be good, column leg intensity is higher, simple structure, cost are lower, construction process is simple, do not influence tunnel section utilization ratio.

Description

U-shaped support device for roadway

Technical Field

The utility model belongs to the technical field of underground mine tunnel and geotechnical engineering tunnel are strutted, especially relate to a tunnel U type support device.

Background

With the increasing underground mines entering deep mining and the implementation of a large number of deep geotechnical engineering in China, the deep high stress environment puts higher requirements on the supporting process. The U-shaped steel yieldable support has the advantages of strong bearing capacity, contractible yielding support and the like, is widely applied to support of mine roadways, railway tunnels and other underground geotechnical engineering tunnels at home and abroad at present, and the application range of the U-shaped steel yieldable support is gradually expanded from soft rock roadways to hard rock roadways. Due to the complex diversity of engineering situations, in engineering practice, the following problems often occur:

firstly, the actual supporting capability is far lower than the theoretical supporting capability: when the load born by the bracket does not reach the bearing limit load, the structure is damaged, and the support fails. The relevant researchers found through a large amount of engineering case statistics and analysis that the main reason causing the phenomenon is that: due to the over-excavation and under-excavation, a large gap exists between the support and the surrounding rock erected after the roadway is excavated, the roof connecting effect is poor, the support and the surrounding rock are in random point and line contact, so that the support is not stressed uniformly after the surrounding rock is deformed and pressed, stress concentration in the support structure is caused under the action of local load and eccentric load, and the support is damaged in advance.

Secondly, passive support limits the bearing performance to play: the U-shaped steel yieldable support is in a contact state with surrounding rocks of a roadway after being erected, but does not generate any active supporting force for the surrounding rocks, the support starts to play a bearing role after the surrounding rocks deform and squeeze the support passively, the support belongs to typical passive support, early deformation of the surrounding rocks cannot be effectively controlled, and full play of the self-bearing performance of the surrounding rocks is limited.

Thirdly, the leg of the bracket is sunk into the bottom plate: the problem is more obvious in the soft rock tunnel, especially in the engineering that the bottom plate intensity is lower, because shank and bottom plate area of contact are less after the support erects, when the support bears the load that comes from the country rock deformation production, the stress that its shank and bottom plate contact position produced is greater than bottom plate intensity, will take place the phenomenon that the support shank sinks into the bottom plate, and then arouse that the country rock deformation is too big to lead to strutting the inefficacy.

To address the above problems in engineering applications, different solutions have been proposed:

the invention patent (CN102926766A) discloses a U-shaped shed capable of being filled behind the wall, after a support is erected in a roadway, firstly, guniting is carried out on the surface of the roadway, gaps such as the U-shaped shed and the surface of surrounding rocks are sealed, then, grouting filling is carried out on a cavity behind the wall by using a specially reserved grouting pipe, the contact area and the structural stress are improved, and the supporting performance is improved; for example, the invention patent (CN105649657A) discloses a U-shaped steel bracket with a flexible stable supporting device, which can perform lateral transfer and energy absorption to a small-area local high stress at a certain position of a roadway, thereby improving the supporting capability and stability of the whole structure; the method has certain effects on the aspects of adjusting the stress state of the support and improving the load distribution, but does not realize the active support of the support to the surrounding rock, and still belongs to passive support.

The utility model discloses a U shaped steel support and surrounding rock stress coupler combined supporting system as in utility model patent (CN202718680U), utilize the rigidity surrounding rock stress coupler that has the screw rod regulatory function to erect between support and surrounding rock, and exert the initial supporting force of certain size, change the irregular point contact between surrounding rock and support into the point contact of equipartition, improve the support stress state; for example, the invention patent (CN107060806A) discloses a U-shaped steel bracket capable of actively stabilizing surrounding rock, wherein an elastic filling body is arranged between the bracket and the surrounding rock, the bracket and an elastic body are fixed on the roadway wall by using an anchor rod penetrating through the bracket and the elastic body, and a certain initial supporting force is applied to the surrounding rock, so that the supporting performance of the bracket is improved. The method can adjust the contact condition of the support and the surrounding rock, and simultaneously the generated active initial supporting force improves the integrity of the supporting system and the self-supporting capability of the surrounding rock to a certain extent, but has the defects of lower initial supporting force, complex construction process, higher cost and the like.

For example, the invention patent (CN103470279A) discloses a U-shaped steel support capable of actively controlling deformation of surrounding rocks, wherein a hydraulic jack and a single hydraulic prop are erected in the internal space of the U-shaped steel support, and the support supports exert a large initial supporting force on the surrounding rocks, so that the stress state of the supports is improved, and active support is realized. However, the cost of the hydraulic equipment adopted by the method is high, so that the supporting cost is greatly improved, and the hydraulic equipment erected in the support occupies a large amount of space, so that the available section area of the roadway is greatly reduced, and the underground equipment personnel can not pass the roadway conveniently.

For the problem that the leg of the support falls into the bottom plate, the most effective method is to weld a steel plate with a certain thickness on the leg of the support to increase the contact area between the leg of the support and the bottom plate, and considering that the steel plate should be uniformly stressed, the leg of the support is usually welded in the center of the steel plate, so that a large gap is formed between the leg of the support and the surrounding rocks on two sides of the roadway, and the deformation control of the support on the surrounding rocks on the two sides is influenced.

In the scheme, the bearing performance of the U-shaped steel bracket is improved by mostly adopting a method for improving the stress state of the bracket, the U-shaped steel bracket still belongs to passive support, and the advantage of active support cannot be exerted; in the scheme with the active supporting characteristic, the method has no advantages in the aspects of economy and feasibility at the cost of complex process and high cost or sacrifice of the utilization rate of the roadway section; according to the scheme, when the U-shaped steel support is actively supported, the basic mechanical properties of the surrounding rock and the relation among the surrounding rock, the support and the active supporting force are not fully considered, and a good supporting effect cannot be achieved.

SUMMERY OF THE UTILITY MODEL

To the problem that current U shaped steel support exists in the tunnel supporting engineering, the utility model provides an use the basic mechanical properties of country rock and ground stress distribution law as the foundation, can effectively improve the whole stress state of U shaped steel support to can provide the controllable initial holding power of load to the country rock, have with the country rock deformation phase adaptation function, the leg structure bending resistance can be good, leg intensity is higher, simple structure, the cost is lower, construction process is simple, do not influence a tunnel U type strutting arrangement of section utilization ratio.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the roadway U-shaped support device comprises support arch crown U-shaped steel, wherein two ends of the support arch crown U-shaped steel are fixedly connected with support leg U-shaped steel through connecting clamp cables, and a support leg expansion device is arranged at the bottom of the support leg U-shaped steel; the stent leg expansion device comprises a lower inner sleeve, an upper outer sleeve, a bunched composite expansion material cartridge and filled river sand; the upper outer sleeve is sleeved outside the lower inner sleeve, a bunched composite expansion material cartridge is arranged in the lower inner sleeve, and river sand is filled in the top and the bottom of the bunched composite expansion material cartridge.

The lower inner sleeve is made of a seamless steel pipe with the outer diameter of 121mm, the inner diameter of 109mm and the wall thickness of 6mm, the length of the steel pipe is 500mm, one end of the steel pipe is open, and a steel plate with the size of 125mm multiplied by 200mm and the thickness of 6mm is welded at the other end of the steel pipe to serve as a base, so that one end of the steel pipe is closed; holes with the diameter of 20mm are respectively arranged at four corners of the steel plate, and in the process of mounting the support, expansion bolts are adopted to firmly fix the support leg expansion device on the roadway bottom plate; 4 drainage exhaust holes with the diameter of 3mm are uniformly drilled on the outer wall of the steel pipe 20mm above the welding position of the steel plate and the steel pipe and are used for drainage before hydration reaction and exhaust in reaction of the bunched composite expansion material cartridge; the outer wall of the steel pipe is sleeved with an elastic rubber ring with the width of 10mm, when the bundled composite expansion material cartridge in the steel pipe is in a soaking and water absorbing stage, the bundled composite expansion material cartridge is sleeved outside the water drainage exhaust hole to be blocked, and after soaking and water absorbing are completed, the bundled composite expansion material cartridge is moved to other parts of the steel pipe to facilitate water drainage and exhaust.

The structure of the upper outer sleeve is similar to that of the lower inner sleeve, the upper outer sleeve is made of a seamless steel pipe with the outer diameter of 133mm, the inner diameter of 122mm and the wall thickness of 5.5mm, the length of the steel pipe is 450mm, one end of the steel pipe is open, and the other end of the steel pipe is welded with a steel plate with the size of 140mm multiplied by 140mm and the thickness of 6mm to seal the steel pipe; the steel plate positioned in the inner area of the steel pipe is provided with a water injection hole with the diameter of 22mm, one side of the steel plate, which faces to the inner space of the steel pipe, is welded with a nut M22, the center of the opening of the nut and the center of the water injection hole are positioned on the same axis, and after water injection is completed, the M22 bolt is screwed into the water injection hole welded with the nut, so that the hydration product of the composite expansion material in the sleeve is sealed.

The inner diameter of the upper outer sleeve is 1mm larger than the outer diameter of the lower inner sleeve, so that a gap of 0.5mm is reserved between the inner wall and the outer wall of the two sleeves to form clearance fit; the open ends of the upper outer sleeve and the lower inner sleeve are inserted oppositely to form a main body structure of the stent leg expansion device.

The bundle-shaped compound expansion material cartridge is a bundle body formed by binding 7 cylindrical compound expansion material cartridges into a whole, the length of the bundle-shaped body is 200mm, the diameter of an external circle of the bundle-shaped body is about 105mm, and the bundle-shaped compound expansion material cartridge can be integrally placed in the inner space of the lower inner sleeve; a certain gap is formed between the compound expansion material cartridges; the composite expansion material cartridge is cylindrical, the diameter of a single body is 35mm, the length of the single body is 200mm, the composite expansion material cartridge is formed by compression molding, demolding and packaging loose composite expansion materials in a specific mold, and the package is made of a paper material with good toughness and good water permeability; the compound expanded material cartridge absorbs and reacts the volume expansion with water after certain moisture, takes place the directional inflation along the steel pipe direction under the restraint of lower part inner skleeve and upper portion outer skleeve, is the utility model discloses well support and country rock initiative meet the top and produce the power source of great initiative initial holding power.

Pack the river sand for conventional building river sand, its main function is for filling the clearance between restrainting form composite expansion material cartridge and the lower part inner skleeve, fills the inside space of restrainting form composite expansion material cartridge, improves composite expansion material's expansibility, strengthens the utility model discloses well support and the initial holding power to the country rock of adaptability ability that the country rock warp.

The bunched composite expansion material cartridge is arranged in the sleeve space of the bracket leg expansion device in an upper section and a lower section, and river sand is filled in the sleeve space to separate the two sections of bunched composite expansion material cartridges, so that the full expansion of the volume of the composite expansion material cartridges during the hydration reaction is facilitated, the active roof connecting effect is improved, and the initial supporting force is improved.

The bundle-shaped composite expansion material cartridge absorbs water and then reacts with volume expansion, is mixed with filling river sand and extruded into a hard and compact hardened body to fill the inner space of the steel tube under the constraint condition in the steel tube, so that the whole support leg expansion device is of a composite structure similar to 'steel tube concrete', the compressive strength and the bending resistance of the part are greatly improved, and the integral support capability and the lateral pressure resistance of two sides of the support are improved.

After the hydration reaction of beam-shaped composite expansion material cartridge, the sclerosis body that generates under the steel pipe constraint condition has the volume and contracts the characteristic of returning under the high pressure condition, and when tunnel country rock pressure lasts the increase, compression support overlap joint position takes place to let the pressure return and contracts, and before reaching connection card cable ultimate strength and destroying, the right amount that the sclerosis body in the expansion device produced returns and contracts when no longer continuing to contract, makes the utility model discloses have the function that "the secondary lets press" is strutted.

The bracket leg U-shaped steel is U-shaped steel used for a traditional U-shaped steel flexible bracket, and comprises leg linear parts and arch lap joint bending parts, the parameters and the size of the U-shaped steel follow the design principle of the traditional U-shaped steel flexible bracket, and the U-shaped steel is designed and selected by considering the shape parameters of the roadway section and the supporting requirements; one end of the straight line part of the leg part is welded at the center of the upper outer sleeve steel plate in the bracket leg expansion device.

The support arch crown U-shaped steel is U-shaped steel used for a traditional U-shaped steel flexible support, the parameters and the size of the support arch crown U-shaped steel follow the design principle of the traditional U-shaped steel flexible support, the design selection is carried out by considering the sectional shape parameters of a roadway and the support requirement, and two ends of the arch crown U-shaped steel are respectively lapped with the bent parts of the support leg U-shaped steel positioned at two sides of the roadway; the lap joint part is connected and pre-tightened by the connecting clamping cable.

The utility model provides a pair of tunnel U type support device when strutting the tunnel country rock, can provide and match, the adjustable initiative holding power of size with country rock mechanical properties according to the basic mechanical properties of tunnel country rock, consequently in concrete engineering is used, should at first develop the basic mechanical properties test of tunnel country rock, then according to the utility model discloses well support shank expansion device is at the axial expansion power output law under the different conditions, design and tunnel country rock assorted expansion device parameter, carry out engineering according to design parameter and use.

The utility model discloses application method in the engineering includes tunnel country rock mechanical properties test, supporting structure and shank expansion device parametric design and site application triplex:

firstly, testing the mechanical property of surrounding rock of a roadway:

performing on-site drilling on the roadway surrounding rock to be supported to obtain a rock core, developing an indoor rock mechanics experiment, and testing basic mechanical parameters such as uniaxial compressive strength, tensile strength, elastic modulus, cohesion, internal friction angle and the like of the rock; and meanwhile, carrying out structural plane investigation work on the area of the roadway surrounding rock, carrying out stability grading on the roadway surrounding rock to be supported based on rock stability indexes and methods, and taking a grading result as a basis for parameter design of a support structure and an expansion device.

Secondly, designing parameters of the support structure and the leg expansion device:

firstly, determining relevant parameters such as U-shaped steel type, size of each part of a support structure, lap joint size of a contractible part, connection clamping cable type and the like according to factors such as roadway section size to be supported, estimated (or actually measured) roadway pressure, roadway surrounding rock stability classification result and the like;

secondly, performing parameter design on the support leg expansion device according to the ground pressure display characteristics of the area where the supporting roadway is located or the stress field distribution rule obtained through actual measurement, wherein when the vertical stress is large and the horizontal stress is not significant, the leg expansion device can be made of a steel pipe with the diameter slightly larger than the section of the U-shaped steel; when the vertical stress is small and the horizontal stress is large, a steel pipe with a large diameter is selected to manufacture the leg expansion device, so that the capability of the leg expansion device for resisting horizontal deformation of surrounding rocks is improved;

and finally, determining the axial expansion force generated by the leg expansion device according to the selected parameters such as the type of the U-shaped steel, the size of each component of the structure, the type of the clamping cable, the pretightening force and the like, and calculating the dosage according to the quantitative relation between the dosage of the bundled composite expansion material cartridge and the axial expansion force generated by the bundled composite expansion material cartridge. By the utility model provides a pair of tunnel U type support device structure can know, in this supporting system, the axial force that bears when the axial expansive force that shank expansion device produced, the cable pretension effect produced at frictional force, the expansion device in compound expanded material sclerosis body produce "the secondary lets press" volume retract to and reach the whole ultimate strength of support, 4 key bearing points when this supporting system bore, and above-mentioned 4 size of bearing points should with the order is unanimous, according to arranging by little to big. Therefore, when the dosage of the bunched composite expansion material cartridge is calculated, the axial expansion force value generated in the leg expansion device and the axial force value born by the hardened body during retraction meet the requirements.

The bearing capacity corresponding to the 4 key bearing points can be measured by indoor experiments to obtain accurate data.

Thirdly, field application steps:

1. drilling 4 drill holes with the depth of 300mm and the diameter of 20mm-22mm at proper positions of bottom plates at two sides of a roadway to be supported, wherein the arrangement of the drill holes corresponds to the openings on the base steel plate of the lower inner sleeve one by one;

2. laying filling river sand with the thickness of about 25mm in the lower inner sleeve, placing the bunched composite expansion material cartridge into the sleeve, pouring a proper amount of the filling river sand, slightly vibrating to fill the river sand into the inside of the bunched composite expansion material cartridge and a gap between the bunched composite expansion material cartridge and the inner sleeve, after the river sand completely covers the top of the bunched composite expansion material cartridge, continuously pouring the river sand into the sleeve to form an isolation cushion layer with the thickness of about 50mm in the sleeve, then placing the other bunched composite expansion material cartridge into the residual space in the sleeve, and repeatedly pouring the river sand and vibrating until the filling river sand is completely flush with the edge of the sleeve;

3. integrally moving an elastic rubber ring on the outer wall of the lower inner sleeve to a water drainage vent hole positioned below the sleeve, plugging a water drainage vent hole on the side wall of the sleeve under the action of rubber tension, and then sleeving an upper outer sleeve welded with U-shaped steel of the leg of the support into the lower inner sleeve;

4. respectively placing the assembled parts at the positions of the holes drilled on the bottom plates at the two sides of the roadway, penetrating the reserved holes at the four corners of the bottom plate of the lower inner sleeve by using expansion bolts, inserting the expansion bolts into the pre-drilled holes on the bottom plate of the roadway, screwing the expansion bolts, fixing the expansion bolts on the bottom plate of the roadway, and rotating U-shaped steel at the leg part of the bracket to enable the parts at the two sides of the roadway to be in an aligned state;

5. erecting support arch U-shaped steel between the aligned support leg U-shaped steel on two sides of the roadway to ensure the lap joint length, and installing a connecting clamping cable at the lap joint part, wherein the whole support needs to be properly adjusted in the installation process, the contact area of the support arch part and the roadway surrounding rock is increased as much as possible, and the connecting clamping cable is screwed down according to the design requirement after the adjustment is finished;

6. the water injection hole reserved on the upper outer sleeve steel plate in the support leg expansion device is used for injecting water into the inner space of the support leg expansion device until the water is in an overflowing state, the water injection is stopped, a bolt matched with a welded nut in the water injection hole is screwed into the water injection hole to seal the inner space of the sleeve, the water discharge hole reserved at the bottom of the lower inner sleeve is temporarily blocked by the elastic rubber ring, the bunched composite expansion material cartridge and the filled river sand in the space of the sleeve are in a completely soaked state by water after the water injection, the composite expansion material in the cartridge absorbs water through the paper shell with good water permeability at the moment, the elastic rubber ring is removed after 10min, and redundant water in the sleeve is discharged along the water discharge hole;

7. after 20min to 40min, the bundle-shaped composite expansion material cartridge in the support leg expansion device starts to react, the volume expansion enables the upper outer sleeve to do piston-like motion along the sleeve barrel body direction, and the support leg U-shaped steel and the support arch U-shaped steel above the upper outer sleeve are pushed to move towards the vault of the roadway, so that the support and the surrounding rock of the roadway are in active roof contact.

Because the arch part of the support is already contacted with surrounding rocks of a roadway at a plurality of places during installation, the continuous expansion displacement generated by the expansion device of the leg part of the support can be continuously output and acted on the whole structure of the support in the form of thrust under the condition that the surrounding rocks of the roadway constrain the support, so that the contact point and the contact area of each part of the support, particularly the arch part, and the wall of the surrounding rocks of the roadway are continuously increased, the whole support is in a relatively uniform stress state, and the integral support capability of the support is favorably improved; meanwhile, active thrust generated in the support leg expansion device is uniformly distributed in the support integral structure, so that each part of the support generates initial supporting force of large load on the surrounding rock of the roadway, the surrounding rock can be in a three-dimensional stress state, the self-stability capability of the surrounding rock is improved, the early deformation after the surrounding rock excavation is effectively controlled, and the advantage that the support and the surrounding rock deformation are supported in a matched mode is fully exerted.

The utility model has the advantages that:

1. the utility model discloses compare with traditional U shaped steel yieldability support, increased expansion device at the support shank, utilize the great displacement that compound expanding material volume expansion thrust unit produced, promote the whole extension of support, realized the support and suited with that the tunnel country rock warp, improved the contact condition and the stress state of support with the country rock, improved the strut performance of support.

2. The utility model discloses compare with current wall back filling etc. and strut technology, the support erects the back, need not to carry out construction processes such as whitewashing, maintenance, slip casting, only needs the water injection and waits for in short time can effectively improve support overall structure stress state, the simple easy operation of work progress.

3. The utility model discloses an expansion device have great propulsion stroke, to the realization that has the condition in great space also can be fine between support and the tunnel country rock wall and the effect that the country rock warp and suit, it is not high to the requirement of tunnel section, application scope is wide.

4. The utility model discloses well expansion device promotes that the support is whole to realize good contact back with the country rock, under the constraint condition of tunnel country rock to the support, the initiative thrust evenly distributed that lasts the inflation production is whole in the support, produces the initiative holding power of great load to tunnel country rock, changes the stress state of country rock, improves the whole ability of stabilizing oneself of country rock, and control country rock early deformation has the characteristics that the initiative was strutted, compares with traditional passive support, and the effect of strutting has obtained the improvement.

5. The utility model discloses after the interior composite expansion material reaction expansion of well expansion device, generate hard fine and close sclerosis body under the steel cylinder restraint condition, its intensity is close to with the concrete, constitutes the composite construction who has similar "steel pipe concrete" jointly with the steel sleeve, has improved resistance to compression and bending resistance by a wide margin, compares with traditional U shaped steel yieldable support, and its shank resists to come from the ability of two group side pressures in tunnel and improves greatly, is particularly useful for the tunnel support that the side pressure is big.

6. The utility model discloses after the interior compound expanded material hydration reaction of well expansion device, the sclerosis body of formation has the volume suitable amount and contracts the characteristic that contracts under the high-pressure condition, consequently when tunnel country rock pressure lasts the increase and acts on the support, the sclerosis body in the expansion device contracts in a suitable amount and contracts, has the characteristic of letting press and strut, combines together with support overlap joint yieldability part, makes the utility model discloses have the function that "the secondary lets press" strut, improved the strut ability of support.

7. The utility model discloses well shank expansion device bottom be equipped with steel pipe size assorted steel sheet, ensure the shank expansion device structure with the tunnel two help the surrounding rock under the prerequisite of abundant contact, increase support shank and the area of contact of bottom plate have effectively solved the support and bear the weight of the problem that the shank is absorbed in the soft rock bottom plate after.

8. The utility model discloses simple structure, the initiative supports the great and stable of load, and expansion device and support overall structure integrated design do not occupy tunnel section space when realizing the initiative and connect the top to strut, and processing technology is simple, the extensive cheap of material source, and overall cost is lower.

Drawings

Fig. 1 is the utility model discloses a three-dimensional schematic diagram of tunnel U type support device

FIG. 2 is a schematic structural section view of the stent leg expansion device of the present invention

The device comprises a bracket leg expansion device 1, a bracket leg U-shaped steel 2, a bracket vault U-shaped steel 3, a connecting clamp cable 4, a lower inner sleeve 1-1, an upper outer sleeve 1-2, a bunched composite expansion material cartridge 1-3, river sand filling 1-4, a bottom plate fixing hole 1-5, a water drainage exhaust hole 1-6, an elastic rubber ring 1-7, a water injection hole 1-8, a water injection hole sealing nut 1-9 and a water injection hole sealing bolt 1-10.

Detailed Description

The invention is described in further detail below with reference to the drawings and specific methods of use.

The working principle is as follows: paving and filling river sand 1-4 and bunched composite expansion material cartridges in a certain sequence in the inner space of a lower inner sleeve 1-1 of a support leg expansion device 1, covering an upper outer sleeve 1-2 welded with support leg U-shaped steel 2, connecting the lap joint part between support vault U-shaped steel 3 and support leg U-shaped steel 2 through a connecting clamp cable 4 and applying a design pretightening force to form a U-shaped steel integral structure; plugging a water drainage exhaust hole 1-6 below a cylinder body of a lower inner sleeve 1-1 by using an elastic rubber ring 1-7, injecting water into a space containing river sand 1-4 and a bunched composite expansion material cartridge 1-3 in a bracket leg expansion device 1 through a water injection hole 1-8 until the water overflows, absorbing water for a certain time by the bunched composite expansion material cartridge 1-3 in a soaking state, removing the elastic rubber ring 1-7, and discharging redundant water from the inner space of the bracket leg expansion device 1; the bundle-shaped composite expansion material cartridge 1-3 and water are subjected to volume expansion reaction, under the constraint of the lower inner sleeve 1-1, displacement is generated along the axial direction to push the upper outer sleeve 1-2 and the bracket leg U-shaped steel 2 above the upper outer sleeve, so that the bracket arch U-shaped steel 3 is pushed to move towards the arch crown of the roadway, all parts of the bracket are enabled to be in active contact with the roadway, the contact part and the contact area are increased, and the contact state of the bracket and surrounding rocks is effectively improved; after the support is wholly fully abutted with the surrounding rock of the roadway under the axial expansion pushing action of the support leg expansion device 1, the support is restrained by the surrounding rock of the roadway, the expansion continuously generated in the support leg expansion device 1 is output in a mode of larger thrust, so that the support wholly generates an active initial supporting force with larger load and more uniform distribution on the surrounding rock of the roadway, on one hand, the integral stress state of the support is improved, the supporting capacity of the support is improved, on the other hand, the initial supporting force on the surrounding rock of the roadway is controlled, the early deformation of the surrounding rock after excavation of the roadway is effectively controlled, the self-supporting capacity of the surrounding rock is favorably fully exerted, and the supporting performance of the support is greatly improved.

The roadway U-shaped support device comprises the following steps:

the method comprises the following steps: the tunnel section size and the estimated (or actually measured) tunnel pressure that support as required confirm the whole size of support, including support shank expansion device 1, support shank U shaped steel 2, support vault U shaped steel 3 parameter, but relevant parameters such as the position overlap joint size of the contraction and 4 models of connecting clamp cable, measure by the indoor experiment the utility model provides a support system required 4 key bearing points correspond the bearing capacity, calculate the quantity of the compound expanded material cartridge 1-3 of the required beam shape in the support shank expansion device 1;

step two: 4 drilling holes with the depth of 300mm and the diameter of 20mm-22mm at proper positions of bottom plates at two sides of a roadway to be supported, wherein the arrangement of the drilling holes is in one-to-one correspondence with the fixing holes 1-5 of the bottom plate on the lower inner sleeve 1-1;

step three: laying filling river sand 1-4 with the thickness of about 25mm in the inner space of the lower inner sleeve 1-1, placing the bundled composite expansion material cartridge 1-3 into the sleeve, pouring a proper amount of filling river sand 1-4, slightly vibrating to fill the filling river sand 1-4 into the bundled composite expansion material cartridge 1-3 and a gap between the filling river sand and the inner sleeve, after the filling river sand 1-4 completely covers the top of the bundled composite expansion material cartridge 1-3, continuously pouring the filling river sand 1-4 to form an isolation cushion with the thickness of about 50mm in the sleeve, then placing the other bundled composite expansion material cartridge 1-3 into the residual space in the sleeve, repeatedly pouring the filling river sand 1-4 and vibrating until the filling river sand 1-4 is completely flush with the edge of the sleeve;

step four: integrally moving an elastic rubber ring 1-7 on the outer wall of a lower inner sleeve 1-1 to a drain vent hole 1-6 positioned below the sleeve, plugging the drain vent hole 1-6 on the side wall of the sleeve under the action of rubber tension, and then sleeving an upper outer sleeve 1-2 welded with a bracket leg U-shaped steel 2 into the lower inner sleeve 1-1;

step five: respectively placing the combined support leg expansion devices 1 at the positions of the holes drilled on the bottom plates at the two sides of the roadway, penetrating the expansion bolts through bottom plate fixing holes 1-5 reserved at four corners of the upper bottom plate of the lower inner sleeve 1-1, inserting the expansion bolts into the pre-drilled holes of the bottom plate of the roadway, screwing the expansion bolts, fixing the expansion bolts on the bottom plate of the roadway, and rotating the support leg U-shaped steel 2 to enable the support leg U-shaped steel 2 at the two sides of the roadway to be in an aligned state;

step six: erecting a bracket arch U-shaped steel 3 between two aligned bracket leg U-shaped steels 2 of two sides of a roadway to ensure the lapping length, and installing a connecting clamping cable 4 at the lapping part, wherein the whole bracket needs to be properly adjusted in the installation process, the contact area of the bracket arch part and the roadway surrounding rock is increased as much as possible, and the connecting clamping cable 4 is screwed down according to the design requirement after the adjustment is finished to apply pre-tightening force to the lapping part;

step seven: water injection holes 1-8 reserved on the steel plate of the outer sleeve 1-2 at the upper part of the bracket leg expansion device 1 are used for injecting water into the inner space of the bracket leg expansion device and stopping injecting water after the water is in an overflowing state, water injection hole sealing bolts 1-10 are screwed into water injection hole sealing nuts 1-9 welded in the water injection holes 1-8, sealing the inner space of the sleeve, wherein a drain vent hole 1-6 reserved at the bottom of a lower inner sleeve 1-1 is temporarily blocked by an elastic rubber ring 1-7, a bundle-shaped composite expansion material cartridge 1-3 and filled river sand 1-4 in the sleeve space are completely soaked by water after water is injected, the composite expansion material in the cartridge absorbs water through a paper shell with good water permeability, the elastic rubber ring 1-7 is removed after 10min, and redundant water in the sleeve is discharged along the drain vent hole 1-6;

step eight: after standing for 20min to 40min, the bundle-shaped composite expansion material cartridge 1-3 in the support leg expansion device 1 starts to react, and the volume expansion enables the upper outer sleeve 1-2 to do piston-like motion along the sleeve barrel body direction, and pushes the support leg U-shaped steel 2 and the support arch U-shaped steel 3 above the upper outer sleeve to move towards the vault of the roadway, so that the support and the surrounding rock of the roadway are initiatively abutted, and the contact state of each part of the support and the surrounding rock of the roadway is improved; and then, the roadway surrounding rock restrains the whole support, at the moment, the bunched composite expansion material cartridge 1-3 in the support leg expansion device 1 continuously reacts and expands, and the output is continued in a thrust mode, so that the whole support generates an active initial supporting force with larger load and more uniform distribution on the roadway surrounding rock, the whole stress state of the support is improved, the early deformation of the excavated surrounding rock is controlled through the active initial supporting force generated by the support on the surrounding rock, the self-bearing capacity of the surrounding rock is fully exerted, and the support performance of the support is improved.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so that any slight modifications, equivalent changes and modifications made by the technical spirit of the present invention to the above embodiments are all within the scope of the technical solution of the present invention.

Claims (5)

1. A U-shaped support device for a roadway comprises support arch crown U-shaped steel, wherein two ends of the support arch crown U-shaped steel are fixedly connected with support leg U-shaped steel through connecting clamp cables, and the support U-shaped steel support device is characterized in that a support leg expansion device is arranged at the bottom of the support leg U-shaped steel; the stent leg expansion device comprises a lower inner sleeve, an upper outer sleeve, a bunched composite expansion material cartridge and filled river sand; the upper outer sleeve is sleeved outside the lower inner sleeve, a bunched composite expansion material cartridge is arranged in the lower inner sleeve, and river sand is filled in the top and the bottom of the bunched composite expansion material cartridge.

2. The roadway U-shaped support device according to claim 1, wherein the lower inner sleeve is a seamless steel tube, one end of the lower inner sleeve is open, the other end of the lower inner sleeve is fixedly connected with an inner sleeve steel plate, and four corners of the inner sleeve steel plate are respectively provided with an opening; a plurality of water drainage vent holes are uniformly formed in the outer wall of the lower inner sleeve; the water drainage vent hole is sleeved with an elastic rubber ring, and the width of the elastic rubber ring is larger than the diameter of the water drainage vent hole.

3. The roadway U-shaped support device according to claim 1, wherein the upper outer sleeve is a seamless steel pipe, one end of the seamless steel pipe is open, the other end of the seamless steel pipe is fixedly connected with an outer sleeve steel plate, a water injection hole is formed in the outer sleeve steel plate, and the water injection hole is communicated with the interior of the upper outer sleeve; and a nut is fixedly connected to one side of the inner space of the upper outer sleeve on the outer sleeve steel plate, and the center of the opening of the nut is coaxial with the water injection hole.

4. The roadway U-shaped bracket device as claimed in claim 1, wherein the bundle-shaped compound expansion material cartridge is a bundle body formed by binding a plurality of cylindrical compound expansion material cartridges; the composite expansion material cartridge is internally provided with a compressed cylindrical composite expansion material, and the outside of the composite expansion material cartridge is coated with a paper material with water permeability.

5. The roadway U-shaped support device as claimed in claim 4, wherein the bundle-shaped composite expansion material cartridge is arranged inside the lower inner sleeve and divided into an upper section and a lower section, and the upper section and the lower section are separated by filling river sand.

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