CN216894429U - Step-by-step sectional type tunnel curtain grouting construction device - Google Patents

Abstract

The utility model discloses a step-by-step sectional type tunnel curtain grouting construction device which comprises a plurality of groups of construction kits and a plurality of built-in gun tubes, wherein each construction kit comprises two grouting pipes and a vacuum pipe and is used for being inserted into grouting holes with different depths; wherein: each grouting pipe is formed by sequentially connecting a plurality of first grouting pipe sections; the vacuum pipe is formed by connecting a plurality of vacuum pipe sections and a plurality of isolation pipe sections which are communicated at intervals, and the middle part of each vacuum pipe section is communicated with the grouting hole; each isolation pipe section is of a double-layer sleeve structure and comprises a second grouting pipe section and an isolation bag sleeve, wherein the second grouting pipe section and the isolation bag sleeve are sleeved together from inside to outside, and two ends of the isolation bag sleeve are attached to outer walls of two ends of the second grouting pipe section in a closed mode to form an expansion bag cavity with two closed ends. The device is inserted into a grouting hole, the grouting hole is divided into a plurality of isolation sections, a plurality of grouting sections divided by isolation pipe sections are formed in the grouting hole, grouting is performed into the closed grouting sections in a segmented mode, grouting pressure is low, and the fluidity of grout is good.

Description

Step-by-step sectional type tunnel curtain grouting construction device

Technical Field

The utility model belongs to the technical field of tunnel grouting reinforcement, and particularly relates to a step-by-step sectional type tunnel curtain grouting construction device.

Background

In the tunnel excavation process, in the broken zone of groundwater fault or the section that gushes mud in the water inrush that can appear, tunnel excavation probably causes the water inrush and gushes mud or groundwater, risk such as earth's surface water loss, through leading tunnel curtain slip casting system groundwater flow, guarantees construction safety. In actual tunnel curtain slip casting construction, slip casting pipes are adopted to circumferentially discharge holes, slip casting is carried out in the slip casting holes, the slip casting is completely injected into the slip casting holes and surrounding rocks by means of large slip casting pressure, no blocking is arranged between the slip casting pipes and the slip casting holes, the slip casting flows into the slip casting holes through the discharge holes in a scattered mode, slip casting needs to be carried out repeatedly, and the amount of the slip casting consumption is large. And the violent extrusion and disturbance can be easily generated to the surrounding stratum, and the large deformation is generated, thereby endangering the safety of the building (structure).

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a step-by-step sectional type tunnel curtain grouting construction device, which is inserted into a grouting hole, the grouting hole is divided into a plurality of isolation sections, a plurality of grouting sections divided by the isolation sections are formed in the grouting hole, grouting is carried out in the closed grouting sections in a sectional manner, the grouting pressure is low, the mobility of grout is good, and the grout diffusion range can be effectively controlled.

The utility model adopts the following technical scheme: a step-by-step sectional type tunnel curtain grouting construction device comprises a plurality of groups of construction kits and a plurality of built-in gun tubes, wherein each construction kit comprises two grouting pipes and a vacuum pipe and is used for being inserted into grouting holes with different depths; wherein:

each grouting pipe is formed by sequentially connecting a plurality of first grouting pipe sections;

the vacuum pipe is formed by connecting a plurality of vacuum pipe sections and a plurality of isolation pipe sections which are communicated at intervals, the vacuum pipe section is connected at the foremost end, and the middle part of each vacuum pipe section is communicated with the grouting hole; each isolation pipe section is of a double-layer sleeve structure and comprises a second grouting pipe section and an isolation bag sleeve which are sleeved together inside and outside, and two ends of the isolation bag sleeve are attached to and sealed with the outer walls of two ends of the second grouting pipe section to form an expansion bag cavity with two sealed ends; the front ends of the first grouting pipe section and the vacuum pipe section at the foremost end are both closed;

the middle sections of the first grouting pipe section and the second grouting pipe section are small-diameter sections, and rubber reset sleeves are sleeved on the small-diameter sections; a plurality of grout overflow holes are circumferentially arranged on the outer wall of the small-diameter section at intervals, each grout overflow hole is in a circular truncated cone shape with a large outer end and a small inner end from outside to inside, and a one-way plug in accordance with the shape of each grout overflow hole is arranged in each grout overflow hole; under the grouting pressure, all the one-way plugs can move outwards in the grout overflow holes, and the outer ends of the one-way plugs jack up the rubber reset sleeves to form grout overflow channels with two ends communicated with the grouting holes; when no grouting pressure exists, the rubber reset sleeve contracts to close the grout overflow channel;

in the isolation pipe section, the slurry overflow channel is communicated with the expansion bag cavity, slurry fills the expansion bag cavity, the outer wall of the expansion bag cavity is attached to block a grouting hole of the section where the expansion bag cavity is located, the grouting hole sections where two vacuum pipe sections which are arranged at intervals are isolated, and the grouting hole is divided into a plurality of isolation sections.

Further, each built-in barrel includes:

the connecting pipes are of multi-section detachably connected pipe body structures, are inserted into the corresponding pipes, have front ends facing the pipe bottoms and can move back and forth in the pipes;

the gun head is a hard tube body and is detachably arranged at the front end of the connecting tube; the front section of the pipe body is solid and closed, and the pipe body in the middle section is provided with a plurality of communicating holes;

the isolation pistons are sleeved at the front end and the rear end of the gun head at intervals, the outer diameter of the isolation pistons is consistent with the inner diameter of the inserted pipe, and the isolation pistons are tightly attached to the pipe wall so as to seal the vacuum pipe or the grouting pipe section between the isolation pistons into a sealed space;

the built-in gun tube is used for sequentially injecting water or grout into the first grouting pipe section, sequentially grouting into each isolation pipe section and vacuumizing each vacuum pipe section.

Further, the vacuum suction device is connected with an internal gun tube inserted into the vacuum tube;

the vacuum pumping device comprises a vacuum pumping barrel, the vacuum pumping barrel comprises a liquid storage barrel which is a vertically placed steel sealed barrel and is used for temporarily storing pumped liquid; the upper end of the liquid storage barrel is provided with a vacuum pump and a negative pressure meter;

the upper part and the lower part of the side wall of the liquid storage barrel are respectively provided with a liquid inlet pipe and a liquid outlet pipe which are communicated with the inner cavity of the barrel, and a liquid inlet valve (84) is arranged on the liquid inlet pipe; a drain valve (85) is arranged on the drain pipe; when water is injected to wash the surrounding rock, the liquid inlet pipe is connected with the rear end of a connecting pipe, and water flow and fine particles are sucked into the liquid storage barrel;

the side wall of the liquid storage barrel is close to the observation window, is arranged on the side wall of the liquid storage barrel, and is provided with the observation window in the area where the liquid inlet pipe is positioned, and is used for observing the color, the character and the flow of the liquid flowing into the barrel from the liquid inlet valve (84) and the height of the liquid level in the barrel.

Further, the lengths of the two grouting pipes are not equal.

The utility model has the beneficial effects that: the method comprises the following steps that 1, pipe groups formed by combining grouting pipes and vacuum pipes are inserted into grouting holes respectively, the grouting holes are blocked by the isolation pipe sections in a segmented mode, the grouting holes are divided into a plurality of isolation sections, then a plurality of grouting sections divided by the isolation pipe sections are formed in the grouting holes, grouting is conducted in the closed grouting sections in a segmented mode, grouting pressure is low, and slurry flowability is good. 2. The matched built-in gun pipes are adopted, the built-in gun pipes are inserted into the pipes, the sections where the pipes are located are sealed, the sections where the pipes are located are vacuumized or grouted, the sections are grouted in a sealed environment, grout flows in a limited space, the grout is saved, and the grouting effect is good. 3. Set up matched with vacuum suction device, in time extract intraductal water and silt out, and can not block up, guaranteed the continuity of construction.

Drawings

FIG. 1 is a schematic structural view of a construction kit in a step-by-step sectional type tunnel curtain grouting apparatus;

FIG. 2 is a schematic structural view of a tube head;

FIG. 3 is a schematic view of the construction of a first and second section of grout;

FIG. 4 is a schematic diagram of a vacuum tube segment;

FIG. 5 is a schematic view of the structure of an isolated pipe section;

FIG. 6 is a schematic view of a built-in gun barrel;

FIG. 7 is a schematic structural view of a vacuum suction apparatus;

FIG. 8 is a 3D schematic view of a step-wise staged tunnel curtain grouting;

FIG. 9 is a schematic diagram of a step-by-step sectional tunnel curtain grouting scheme showing the arrangement of grouting holes and orifices in a longitudinal cross-sectional view;

FIG. 10 is a longitudinal sectional view of a grout tube and vacuum tube inserted into the grout hole;

FIG. 11 is a schematic view of the formation of a water flow channel in the surrounding rock;

FIG. 12 is a schematic diagram of the structure of the chemical grout injected into the surrounding rock;

FIG. 13 is a schematic view of the structure of the surrounding rock into which cement slurry is injected;

wherein: 1. grouting pipes;

2. a vacuum tube;

3. a pipe head;

4. a slurry overflow hole; 4-1, a first grouting pipe section; 4-2, a second grouting pipe section; 41. a one-way plug; 42. a rubber reset sleeve;

5. a vacuum pipe section; 51. a vent hole; 52. an isolation net;

6. an isolation capsule sleeve; 6a, isolating the pipe section; 61. a sealing band; 62. an expansion sleeve;

7. a barrel is arranged inside; 71. a gun head; 72. an isolation piston; 73. a connecting pipe; 74. a quick coupling; 75. a communicating hole;

8. a vacuum pumping barrel; 81. a liquid storage barrel; 82. a vacuum pump; 83. a negative pressure gauge; 84. a liquid inlet valve; 85. a drain valve; 86. observation window.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The utility model discloses a step-by-step sectional type tunnel curtain grouting construction device, which comprises a plurality of groups of construction kits and a plurality of built-in gun tubes 7, wherein: as shown in fig. 1, each construction kit comprises two grouting pipes 1 and a vacuum pipe 2, which are inserted into grouting holes with different depths; the lengths of the two grouting pipes 1 are not equal. Wherein: each grouting pipe 1 is formed by sequentially connecting a plurality of first grouting pipe sections 4-1.

As shown in fig. 3 and 5, the vacuum tube 2 is composed of a plurality of vacuum tube segments 5 and a plurality of isolation tube segments 6a which are communicated with each other, the vacuum tube segment 5 is connected with the foremost end, and the middle part of each vacuum tube segment 5 is communicated with the grouting hole; each isolation pipe section 6a is of a double-layer sleeve structure and comprises a second grouting pipe section 4-2 and an isolation bag sleeve 6 which are sleeved together from inside to outside, and two ends of the isolation bag sleeve 6 are attached to and sealed with outer walls of two ends of the second grouting pipe section 4-2 to form an expansion bag cavity with two closed ends; as shown in fig. 2, a tapered closed pipe head 3 is connected to each of the front ends of the first grouting pipe section 4-1 and the vacuum pipe section 5 at the foremost end, and the front end of the pipe head 3 is closed. When inserting slip casting pipe 1 and vacuum tube 2 in the injected hole, the setting of toper tube head 3 more makes things convenient for the guide to move ahead, is difficult to damaged. As shown in FIG. 4, a vent hole 51 is arranged in the middle of the vacuum pipe section 5, and an isolation net 52 is wrapped on the outer side of the pipe wall for preventing large-particle silt from entering the vacuum pipe section.

Each isolation capsule sleeve 6 comprises an expansion sleeve 62 and two sealing hoops 61 which are both in a hollow cylinder structure, wherein the sealing hoops 61 are made of PVC hard plastic materials, the expansion sleeve 62 is made of high-elasticity rubber materials, the sealing hoops 61 are positioned on the expansion sleeve 62 and are tightly adhered together at the end parts through hot processing to form the integral hollow isolation capsule sleeve 6 with the sealing hoops 61 at the two ends and the expansion sleeve 62 in the middle.

The inner diameter of the sealing hoop 61 is matched with the outer diameter of the second grouting pipe section 4-2, the sealing hoop can be sleeved outside the second grouting pipe section 4-2 to slide, the isolating bag sleeve 6 is sleeved from one end of the second grouting pipe section 4-2 to finally wrap the second grouting pipe section 4-2, glue is smeared on the outer diameters of two ends of the second grouting pipe section 4-2, and the sealing hoop 61 is bonded and fixed to enable the sealing hoop not to slide and form sealing.

As shown in fig. 3, the first grouting pipe section 4-1 and the second grouting pipe section 4-2 are both made of PVC hard plastic material, each full pipe section is a through uniform inner diameter, one end of the pipe is provided with an external thread, and the other end of the pipe is provided with an internal thread for the combined connection of each pipe section. One section of the middle part of each of the first grouting pipe section 4-1 and the second grouting pipe section 4-2 is a small-diameter section, a rubber reset sleeve 42 is sleeved on the small-diameter section, and the small-diameter section is arranged to limit the sliding of the rubber reset sleeve 42. And for the second grouting pipe section 4-2, the overall outer diameter of the second grouting pipe section 4-2 after the rubber resetting sleeve 42 is installed is reduced, so that the isolation bag sleeve 6 can be conveniently penetrated and sleeved subsequently.

On the outer wall of the small-diameter section, a plurality of grout overflow holes 4 are circumferentially arranged at intervals in a circle, each grout overflow hole 4 is in a circular table shape with a large outer end and a small inner end from outside to inside, a one-way plug 41 consistent with the shape of each grout overflow hole 4 is arranged in each grout overflow hole 4, and each one-way plug 41 is made of rubber. Under the grouting pressure, each one-way plug 41 can move outwards in the grout overflow hole 4, and the outer end jacks up the rubber reset sleeve 42 to form a grout overflow channel with two communicated ends; when no grouting pressure exists, the rubber reset sleeve 42 contracts to close the grout overflow channel;

in the isolation pipe section 6a, the slurry overflow channel is communicated with the expansion bag cavity, slurry fills the expansion bag cavity, the outer wall of the expansion bag cavity is attached to block the grouting hole of the section where the expansion bag cavity is located, the grouting hole sections where two vacuum pipe sections 5 which are arranged alternately are isolated, and the grouting hole is divided into a plurality of isolation sections.

The above-mentioned a plurality of built-in gun pipes 7, each built-in gun pipe 7 is used for inserting in corresponding vacuum tube 2 and slip casting pipe 1, and each built-in gun pipe 7 all includes: the connecting pipes 73 are inserted into the corresponding pipes, the front ends of which face the pipe bottoms, and the connecting pipes can move back and forth in the pipes; the connecting pipes 73 are connected through quick connectors 74; the gun head 71 is a hard pipe body and is detachably arranged at the front end of the connecting pipe 73; the front end section is solid and closed, and the pipe body in the middle section is provided with a plurality of communicating holes 75.

The number of the isolation pistons 72 is two, the isolation pistons are sleeved at the front end and the rear end of the gun head 71 at intervals, namely, the part of the gun head 71, which is provided with the communicating hole 75, is positioned between the two isolation pistons 72, the outer diameter of each isolation piston 72 is consistent with the inner diameter of the pipe into which the isolation piston is inserted, and the isolation pistons 72 are tightly attached to the pipe wall so as to seal the vacuum pipe 2 or the grouting pipe 1 section positioned between the isolation pistons 72 into a closed space, and the isolation pistons 72 move along with the movement of the connecting pipe 73 so as to sequentially seal different sections of the vacuum pipe 2 or the grouting pipe 1 into closed spaces;

the built-in gun tube 7 is used for sequentially injecting water or grout into the first grouting pipe section 4-1, sequentially grouting into each isolation pipe section 6a and vacuumizing each vacuum pipe section 5.

As shown in FIG. 7, the stepped sectional type grouting apparatus for a tunnel curtain further comprises a vacuum suction device for connecting with the built-in gun tube 7 inserted into the vacuum tube 2.

The vacuum pumping device comprises a vacuum pumping barrel 8, the vacuum pumping barrel 8 comprises a liquid storage barrel 81 which is a vertically arranged steel sealing barrel,can resist the external atmospheric pressure without deformation when vacuum is formed in the barrel, and the volume of the barrel is not less than 1m³For temporarily storing the pumped liquid; a vacuum pump 82 and a negative pressure gauge 83 are arranged at the upper end of the liquid storage barrel 81; the vacuum pump 82 is communicated with the interior of the liquid storage barrel 81 and is used for pumping air in the barrel to form vacuum negative pressure. The negative pressure gauge 83 is communicated with the interior of the liquid storage barrel 81 and is used for monitoring the vacuum degree in the barrel.

The upper part and the lower part of the side wall of the liquid storage barrel 81 are respectively provided with a liquid inlet pipe and a liquid outlet pipe which are communicated with the inner cavity of the barrel, and a liquid inlet valve 84 is arranged on the liquid inlet pipe; a drain valve 85 is installed on the drain pipe, and the drain valve 85 is a large-diameter ball valve. When water is injected to wash the surrounding rock, the liquid inlet pipe is connected with the rear end of the connecting pipe 73, and water flow and fine particles are sucked into the liquid storage barrel 81.

The side wall of the liquid storage barrel 81 is close to the observation window 86, is arranged on the side wall of the liquid storage barrel 81, and is provided with the observation window 86 in the area where the liquid inlet pipe is positioned, and is used for observing the color, the property and the flow of the liquid flowing into the barrel from the liquid inlet valve 84 and the height of the liquid level in the barrel.

The construction method using the step-by-step sectional type tunnel curtain grouting construction device comprises the following steps:

step one, grouting holes are formed:

on the grout stop wall, taking the center of the tunnel as the center of a circle, arranging a plurality of radial extensions at intervals along the direction of contour lines of the vault and the side walls of the tunnel, designing three orifices of grouting holes at the inner side, the middle part and the outer side at intervals from inside to outside on each same radial extension, and designing the angle and the depth of each grouting hole; selecting a radially extending grouting hole orifice to be used as a grouting hole, and obtaining the final hole position of the grouting hole in the surrounding rock; wherein: the final holes of the middle and outer grouting holes are positioned at the cross section of the terminal of the section to be reinforced of the tunnel, and the final hole of the inner grouting hole is positioned at the cross section of the middle of the section to be reinforced of the tunnel. The included angle between each two adjacent radial extensions is the same, and as shown in fig. 9, the grouting holes are arranged as follows: the inner side, the middle and the outer side grouting holes are all multiple in orifices, the number of the orifices is the same, and the orifices of the inner side, the middle and the outer side grouting holes are all arranged in an arch shape along the contour lines of the vault and the side walls of the tunnel.

The method is characterized in that three grouting hole orifices on the inner side, the middle side and the outer side on the same radial extension are used as a group, the length of the circulating grouting reinforcement section is 20m, the cross section of a tunnel at the end point of the reinforcement section is a final length cross section, the cross section of the tunnel at the middle (namely 10m) of the length of the circulating grouting reinforcement section is a middle cross section, the end hole position of the inner side hole is an intersection point of a radial plane of the group and a tunnel excavation contour line in the final length cross section, the end hole position of the middle hole is an intersection point of a radial plane and a radial reinforcement range contour line in the final length cross section, and the end hole position of the outer side grouting hole is an intersection point of a reinforcement range contour line in the radial plane and the middle cross section of the group.

Step two, setting vacuum isolation sections in sections:

the vacuum pipe 2 is inserted into the inner grouting hole to the bottom of the hole, the second grouting pipe section 4-2 at the bottom of the hole sequentially retreats to the end of the hole, grout is sequentially injected into each second grouting pipe section 4-2, the grout overflows the rubber reset sleeve 42 through the one-way plug 41 under the action of grouting pressure and enters the expansion bladder cavity, and the isolation bladder sleeve 6 expands to plug the grouting hole at the section, so that the plugging of the grouting hole at each isolation pipe section 6a is completed.

The specific process of the second step is as follows: inserting a built-in gun tube 7 into the vacuum tube 2, wherein the gun head 71 is positioned at the second grouting tube section 4-2 at the bottom of the hole, and the orifice end of the built-in gun tube 7 is connected with a grouting device; the gun head 71 sequentially retreats from the bottom of the hole to the orifice and is sequentially positioned in each second grouting pipe section 4-2; in each second grouting pipe section 4-2, two isolation pistons 72 are tightly attached to the inner wall of the second grouting pipe section 4-2, and a closed space is formed between the two isolation pistons 72; in each second grouting pipe section 4-2, grout is injected by the gun head 71, the grout is cement-water glass double-grout, under the action of grouting pressure, the grout enters and fills the expansion bladder cavity, the isolation bladder sleeve 6 expands to plug the grouting hole of the section where the isolation bladder sleeve is located, so that the grouting hole outside the vacuum pipe 2 forms a plurality of sections which are isolated from each other, namely the grouting hole sections where two vacuum pipe sections 5 which are arranged alternately are isolated.

The purpose of the subsection that the slip casting hole outside the vacuum tube 2 formed the mutual isolation of multistage lies in, when the vacuum suction drainage, can divide into the multistage with the gravitation source, draws close distance with each section slip casting water source, strengthens the vacuum pumping effect, makes the country rock in the full length within range can not appear losing the leakage region, also is convenient for better control slip casting construction overall process's influence scope, avoids the material extravagant.

Step three, injecting water to wash the surrounding rock, and forming a water flow channel in the surrounding rock:

the grouting pipes 1 in the middle and the outer grouting holes are respectively inserted with a built-in gun barrel 7 to the bottom, the vacuum pipe 2 is inserted with a built-in gun barrel 7 to the bottom, and the orifice end of the vacuum pipe is connected with a vacuum suction device; synchronously backing the two built-in gun pipes 7 of the middle grouting pipe 1 and the vacuum pipe 2 to the orifice end in sections, and injecting clear water into the first grouting pipe section 4-1 in each section; pumping each vacuum pipe section 5 into a negative pressure state, forming a negative pressure area between the vacuum pipe section 5 and the grouting holes, guiding pressurized clean water to wrap fine particles to flow to the negative pressure area, flowing into the vacuum pipe section 5 and discharging the fine particles out of the vacuum pipe 2, and forming a plurality of water flow channels in surrounding rocks between the middle grouting holes and the inner side grouting holes in the flowing process of the clean water; and repeating the operation to form a plurality of water flow channels in the surrounding rock between the outer side grouting holes and the inner side grouting holes. The formed water flow channel is used as a channel for subsequent grouting and is formed by washing out a certain amount of stratum fine particles, and subsequent grouting is used for filling and replacing, so that the disturbance to the stratum is relatively small, and the safety of surrounding buildings (structures) is ensured.

The concrete process of the third step is as follows:

inserting a built-in gun barrel 7 into the middle grouting pipe 1, enabling the gun head 71 to reach a first grouting pipe section 4-1 at the bottom, sequentially retreating the gun head 71 from the first grouting pipe section 4-1 at the bottom end to the orifice end, sequentially and respectively locating in each first grouting pipe section 4-1, and enabling two isolation pistons 72 to be tightly attached to the inner wall of the first grouting pipe section 4-1 in each first grouting pipe section 4-1 to form a closed space between the two isolation pistons 72; injecting water into the built-in gun barrel 7, and injecting the water into a closed space in the first grouting pipe section 4-1 through a gun head 71; as the water injection pressure rises, the water flow backs up the one-way plug 41 and the rubber reset sleeve 41 and is injected into the surrounding rock, and a water outlet source with pressure is formed at the point.

Meanwhile, the vacuum suction device is connected with the built-in gun barrel 7 in the vacuum tube 2, the gun head 7 is positioned in the vacuum tube section 5 at the bottom of the hole, and the gun head 71 sequentially retreats towards the orifice end and is sequentially positioned in each vacuum tube section 5 respectively in synchronization with water injection; in each vacuum pipe section 5, a closed space is formed between two isolation pistons 72 and the section of the vacuum pipe section 5 provided with the vent hole 51, a liquid inlet pipe of the vacuum pumping and discharging barrel 8 is connected with the built-in gun barrel 7, the vacuum pump 82 is started to pump and discharge, the vacuum negative pressure is controlled to be about 1MPa according to the indication number of the negative pressure meter 83, and the position of the gun head 71 is communicated with the surrounding rock through the vent hole 51 and the isolation net 52. A vacuum negative pressure source is formed in the surrounding rock at the grouting hole of the section, clear water output by the gun head 71 is guided to flow towards the surrounding rock in a one-way mode, meanwhile, water flow is utilized for wrapping, some fine particles penetrate through the separation net 52 to be sucked into the built-in gun barrel 7 and finally flow into the vacuum exhaust barrel 8, a plurality of water flow channels are formed in the surrounding rock between the middle grouting hole and the inner side grouting hole, and the water flow channels are further enlarged and smooth along with continuous loss of the fine particles in the surrounding rock.

Focusing on the flow of water into the reservoir 81 through the inlet valve 84 through the observation window 86, when the water is relatively clear and free of fine particles such as silt, and the flow rate of the pumped water exceeds 1/2 of the flow rate of the injected water, a sufficiently clear flow path is formed in the formation. When the subsection moves backwards, the grouting machine is closed, water injection is suspended, and the liquid inlet valve 84 of the vacuum exhaust barrel 8 is closed. The inner barrel 7 is pulled towards the port to the next adjacent section of pipe, forming a plurality of water flow channels in the surrounding rock between the outer and inner grout holes. As shown in fig. 8, 10 and 11.

During the operation, the observation window 86 is used for observing, if the water level in the liquid storage barrel 81 exceeds 2/3, the water injection and pumping operation is suspended, the liquid discharge valve 85 is opened to discharge water and silt, then the liquid discharge valve 85 is closed, and the pumping operation is resumed.

Injecting chemical grout to form primary grout veins:

as shown in fig. 12, from the first grouting pipe section 4-1 at the bottom of the grouting pipe 1 in the middle and outer grouting holes, respectively, the grouting pipes go backwards in sections in sequence towards the orifice end, and chemical grout is injected into each section of grouting pipe in sequence; meanwhile, in synchronization with the injection of chemical grout, the vacuum pipe sections 5 at the bottom of the hole are sequentially and sectionally retreated, each vacuum pipe section 5 is vacuumized, and then the chemical grout in the grouting pipe section on the same cross section as the vacuum pipe section 5 flows into and fills a water flow channel in the surrounding rock and is solidified to form primary grout veins. In the third step, by utilizing sectional retreating type under-pressure grouting and vacuum negative pressure suction, the surrounding rock is fully filled with chemical grout with low strength and slightly poor diffusivity along a water flow channel, an extended network-shaped grout pulse is formed after hardening, meanwhile, the grout pulse and the surrounding rock form a contact surface, but the mechanical property is weak, and cement grout needs to be injected for better stability of the surrounding rock.

As shown in fig. 13, after the chemical grout is solidified to form a primary grout vein, the cement grout is injected to form a composite grout vein, specifically: and injecting the cement slurry into a channel filled with the chemical slurry from the grouting pipe 1 in the middle grouting hole to the grouting pipe 1 in the outer grouting hole by adopting a method for injecting the chemical slurry to form a composite slurry vein coated by the cement slurry and the primary slurry vein. The cement slurry has high strength and poor diffusivity, when the cement slurry is contacted with the surface of the chemical slurry vein, the cleavage grouting is carried out on the surface of the chemical slurry vein, the fluidity is good, the grouting amount is improved, and the surrounding rock is extruded and compacted in the surrounding rock to form the composite network-shaped slurry vein externally wrapped with the cement slurry vein and internally sandwiched with the chemical slurry vein.

The concrete process of the step four is as follows:

inserting a built-in gun barrel 7 into a grouting pipe 1 in a middle grouting hole, wherein a gun head 71 is positioned at a first grouting pipe section 4-1 at the bottom end, two isolation pistons 72 are tightly attached to the inner wall of the first grouting pipe section 4-1, and a closed space is formed between the two isolation pistons 72; meanwhile, another built-in gun tube 7 is inserted into the vacuum tube 2, the gun head 71 is positioned at the vacuum tube section 5 at the bottom end, and in each vacuum tube section 5, a closed space is formed between two isolation pistons 72 and the section of the vacuum tube section 5 provided with the vent hole 51;

the two built-in gun pipes 7 drive the gun heads 71 to synchronously and sequentially retreat to the orifice ends from the bottoms of the orifices to the orifices, and the following operations are sequentially carried out in the first grouting pipe sections 4-1 and the vacuum pipe sections 5 of each section: and injecting chemical grout into the first grouting pipe section 4-1, simultaneously sucking by a vacuum suction device, vacuumizing the closed space, enabling the chemical grout to flow into the water flow channel, and sucking the grout into the vacuum suction device when the water flow channel is filled with the chemical grout, so that grouting of the chemical grout is finished. Specifically, the liquid flowing into the liquid storage barrel 81 through the liquid inlet valve 84 is focused through the observation window 86, and when the chemical slurry flows out, the water flow channel of the stratum is filled with the chemical slurry. During operation, if the water level in the liquid storage barrel 81 exceeds 2/3 by observation through the observation window 86, grouting and pumping are suspended, the drainage valve 85 is opened to drain water and waste slurry, and then the drainage valve 85 is closed to resume operation.

And step five, repeating the step one to the step four to finish the grouting of the tunnel curtain. And finally, forming an arch-shaped reinforced area along the outer area of the tunnel excavation contour line.

In the utility model, the following modes are adopted: setting an isolation section, injecting water, injecting chemical slurry and injecting slurry, and distributing sectional type tunnel curtain slurry injection, wherein after the chemical slurry is solidified, a slurry stone body and a stratum form a contact surface, but because the strength of the chemical slurry stone body is very low (the unconfined compressive strength is about 0.5MPa), the surrounding rock reinforcing effect is poor at the moment, further treatment is needed, and then injecting the cement slurry to form a composite slurry vein, specifically: and injecting the chemical grout into the channel with the injected chemical grout to form a composite grout vein coated with the cement grout and the primary grout vein. After the chemical grout is injected, the contact surface of the chemical grout stone body and the stratum becomes a weak surface, and the cement grout generates stress concentration along the surface under the action of grouting pressure, so that splitting and flowing are easy to occur, the resistance of an original stratum is overcome, the injection amount of the grout is greatly improved, a composite grout vein externally wrapped with a grout vein and internally sandwiched with a chemical grout vein is formed, and the grouting reinforcement of the stratum is finished.

Claims (4)

1. The step-by-step sectional type tunnel curtain grouting construction device is characterized by comprising a plurality of groups of construction kits and a plurality of built-in gun pipes (7), wherein each construction kit comprises two grouting pipes (1) and a vacuum pipe (2) and is used for being inserted into grouting holes with different depths; wherein:

each grouting pipe (1) is formed by sequentially connecting a plurality of first grouting pipe sections (4-1);

the vacuum pipe (2) is formed by connecting a plurality of vacuum pipe sections (5) and a plurality of isolation pipe sections (6a) which are communicated at intervals, the vacuum pipe section (5) is connected at the foremost end, and the middle part of each vacuum pipe section (5) is communicated with the grouting hole; each isolation pipe section (6a) is of a double-layer sleeve structure and comprises a second grouting pipe section (4-2) and an isolation bag sleeve (6), wherein the second grouting pipe section (4-2) and the isolation bag sleeve are sleeved together, and two ends of the isolation bag sleeve (6) are attached to and sealed with the outer walls of two ends of the second grouting pipe section (4-2) to form an expansion bag cavity with two closed ends; the front ends of the first grouting pipe section (4-1) and the vacuum pipe section (5) at the foremost end are closed;

the middle sections of the first grouting pipe section (4-1) and the second grouting pipe section (4-2) are small-diameter sections, and rubber reset sleeves (42) are sleeved on the small-diameter sections; a plurality of slurry overflow holes (4) are circumferentially arranged on the outer wall of the small-diameter section at intervals, each slurry overflow hole (4) is in a circular truncated cone shape with a large outer end and a small inner end from outside to inside, and a one-way plug (41) which is consistent with the shape of each slurry overflow hole (4) is arranged in each slurry overflow hole; under the grouting pressure, each one-way plug (41) can move outwards in the grout overflow hole (4), and the outer end of the one-way plug jacks up the rubber reset sleeve (42) to form a grout overflow channel with two communicated ends, which is communicated with the grouting hole; when no grouting pressure exists, the rubber reset sleeve (42) contracts to close the slurry overflow channel;

in the isolation pipe section (6a), a slurry overflow channel is communicated with the expansion bladder cavity, slurry fills the expansion bladder cavity, the outer wall of the expansion bladder cavity is attached to seal the grouting hole of the section where the expansion bladder cavity is located, the grouting hole sections where two vacuum pipe sections (5) which are arranged at intervals are isolated, and the grouting hole is divided into a plurality of isolation sections.

2. A staged sectional tunnel curtain grouting construction device according to claim 1, wherein each of the built-in gun tubes (7) includes:

the connecting pipe (73) is of a multi-section detachably connected pipe body structure, is inserted into the corresponding pipe, has the front end facing the pipe bottom, and can move back and forth in each pipe;

the gun head (71) is a hard pipe body and is detachably arranged at the front end of the connecting pipe (73); a section of the front end of the tube body is solid and closed, and a plurality of communicating holes (75) are formed in the tube body at the middle section;

the isolation pistons (72) are sleeved at the front end and the rear end of the gun head (71) at intervals, the outer diameters of the isolation pistons are consistent with the inner diameters of the inserted pipes, the isolation pistons are tightly attached to the pipe walls, so that the sections of the vacuum pipes (2) or the grouting pipes (1) positioned between the isolation pistons (72) are sealed into closed spaces, the isolation pistons (72) move along with the movement of the connecting pipes (73), and different sections of the vacuum pipes (2) or the grouting pipes (1) are sequentially sealed into closed spaces;

the built-in gun barrel (7) is used for sequentially injecting water or grout into the first grouting pipe section (4-1), sequentially grouting into each isolation pipe section (6a) and vacuumizing each vacuum pipe section (5).

3. A sectional type tunnel curtain grouting construction device according to claim 2, further comprising a vacuum suction device for connecting with a built-in gun tube (7) inserted into the vacuum tube (2);

the vacuum pumping device comprises a vacuum pumping barrel (8), wherein the vacuum pumping barrel (8) comprises a liquid storage barrel (81) which is a vertically-arranged steel sealed barrel and is used for temporarily storing pumped liquid; a vacuum pump (82) and a negative pressure meter (83) are arranged at the upper end of the liquid storage barrel (81);

the upper part and the lower part of the side wall of the liquid storage barrel (81) are respectively provided with a liquid inlet pipe and a liquid outlet pipe which are communicated with the inner cavity of the barrel, and a liquid inlet valve (84) is arranged on the liquid inlet pipe; a drain valve (85) is arranged on the drain pipe; when water is injected to wash the surrounding rock, the liquid inlet pipe is connected with the rear end of a connecting pipe (73), and water flow and fine particles are sucked into the liquid storage barrel (81) through suction;

on the lateral wall of stock solution bucket (81), and be close to observation window (86), set up on stock solution bucket (81) lateral wall, and be located feed liquor pipe place region is provided with observation window (86) for observe color, property and the flow of feed liquor valve (84) inflow bucket interior liquid, and the height of liquid level in the bucket.

4. A stepwise segmented tunnel curtain grouting construction device according to claim 3, wherein the lengths of the two grouting pipes (1) are not equal.

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