A device and construction method for preventing collapse of unstable exposed karst caves at the top during tunnel construction

Abstract

The present invention discloses a device and construction method for preventing the collapse of a karst cave with unstable top exposure during tunnel construction. The device comprises a vertical support and an arch support. The vertical support is located in the tunnel and is arranged along the tunnel face. The arch support extends along the designed top surface of the tunnel. A spring buffer is arranged between the top of the vertical support and the arch support. An inflatable tarpaulin is fixed between the two side edges of the arch support. A height adjustment component is arranged between the arch support and the inflatable tarpaulin. A self-sealing component is arranged on the inflatable tarpaulin. The device can not only fit tightly with the top surface of the karst cave, but also improve the overall stability of the device.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel support, and in particular to a device and a construction method for preventing top unstable exposed karst caves from collapsing during tunnel construction. Background Art

[0002] The 19th century was the era of bridges, the 20th century was the era of high-rise buildings, and the 21st century is the era of underground space. In recent years, with the rapid development of my country's economy, the need for transportation infrastructure construction has been increasing, and the construction of highway tunnels has greatly improved the convenience of transportation in the western mountainous areas. At present, my country has become one of the countries with the largest scale, technology and difficulty in tunnel construction in the world. At the same time, with the gradual implementation of the western development strategy, the focus of highway and railway engineering construction has gradually shifted to the western mountainous areas with highly developed karst, which will bring huge challenges to geological surveys, construction safety and ecological environment.

[0003] Karst is a very common geological phenomenon on Earth, and it is found in rocks ranging from high mountains to rocks thousands of meters deep in the earth's crust. my country has a vast territory, with great differences in topography and landforms from east to west. The regional geological conditions are very complex, and karst geology is one of the typical complex geological conditions. my country is one of the countries with the most extensive distribution of karst geology in the world, with 9.6 million km2 of karst geology in the country. 2 In terms of national land area, the distribution area of ​​soluble rock layers is about 3.443 million km 2 , accounting for 1 / 3 of the country's land area. Karst geology is distributed throughout my country's provinces, municipalities and autonomous regions, especially in Yunnan, Guizhou and Guangxi in southwest my country. In addition, there are also a large number of distributions in Shanxi, Guangdong, Taiwan, Hunan, Zhejiang, western Hubei, Sichuan, southern Shaanxi and North China. According to incomplete statistics of railway tunnels built and under construction in the west, tunnels located in karst areas account for about 50%. According to statistics of 26 highway and railway long tunnels built in karst areas, almost all of them encountered karst collapse and water gushing disasters to varying degrees during construction. There were as many as 10 tunnels that had suffered major karst disasters, accounting for 38.64%; and among the 17 karst medium and long tunnels (2km-3km) in the southwest and central-south regions, nearly 50% had suffered major karst disasters.

[0004] Therefore, how to comprehensively determine the stability of karst tunnel construction and excavation from various influencing factors, and how to grasp the timing and treatment plan for geological disasters during karst tunnel excavation have become urgent issues to be solved in the current karst tunnel excavation.

[0005] During tunnel excavation, caves will be encountered. The existing support mainly adopts concrete retaining wall or shotcrete support technology. Its support capacity cannot achieve the expected support effect under such complex geological conditions, mainly because the support structure and the cave are not tightly combined and cannot be deformed together. The utility model patent with publication number CN212454440U discloses a rapid support structure for a cave exposed on a single side wall of a tunnel. The support structure can make the support structure fit tightly with the top of the cave, but it will affect the telescopic rod during the grouting process, causing the displacement or deformation of the telescopic rod, thereby affecting the support effect. Summary of the invention

[0006] In view of the above-mentioned problems, the present invention aims to provide a collapse prevention device and construction method for unstable exposed caves at the top during tunnel construction, which can not only make the collapse prevention device fit tightly with the top surface of the cave, but also improve the overall stability of the collapse prevention device.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A device for preventing a cave from collapsing when the top of a tunnel is unstable and exposed during construction, wherein the cave is located at the top of the tunnel face, and wherein the device is characterized in that: the device comprises a vertical support and an arch support, wherein the vertical support is located in the tunnel and is arranged along the tunnel face;

[0009] The arch support extends along the designed top surface of the tunnel, and a spring buffer is provided between the top of the vertical support and the arch support;

[0010] An inflatable tarpaulin is fixedly arranged between the two side edges of the arch support, and a height adjustment component is arranged between the arch support and the inflatable tarpaulin; and a self-sealing component is arranged on the inflatable tarpaulin.

[0011] Furthermore, the height adjustment assembly includes a plurality of first support columns vertically arranged on the top of the arch support, each of the first support columns is provided with a first telescopic support assembly, the first telescopic support assembly passes through the top of the first support column, and the top of the first telescopic support assembly is fixedly connected to the inflatable tarpaulin;

[0012] A triangular support assembly is slidably provided on the left and right sides of each of the first support columns, the top of the triangular support assembly and the end away from the first support column are fixedly connected to the inflatable tarpaulin, and the end of the triangular support assembly close to the first support column is slidably connected to the side surface corresponding to the first support column.

[0013] Furthermore, the triangular support assembly includes a second support column, the bottom of the second support column is fixedly connected to the top of the arch support, the top of the second support column is provided with a second telescopic support assembly, and the top of the second telescopic support assembly is fixedly connected to the inflatable tarpaulin;

[0014] The left and right sides of the second support column are movably connected with a third support column and a fourth support column respectively, a third telescopic support assembly is arranged in the third support column, an end of the third telescopic support assembly passes through the third support column, and an end of the third telescopic support assembly located outside the third support column is also fixedly connected to the inflatable tarpaulin; a first telescopic rod is fixedly arranged at an end of the fourth support column away from the second support column, and an end of the first telescopic rod away from the fourth support column is slidably connected to the first support column.

[0015] Furthermore, a movable through hole in the up-and-down direction is provided on the second support column, a support block is slidably provided in the movable through hole, a first connecting rod and a second connecting rod are movably provided on both sides of the support block, one end of the first connecting rod is movably connected to the support block, and the other end of the first connecting rod is slidably connected to the third support column; one end of the second connecting rod is also movably connected to the support block, and the other end of the second connecting rod is slidably connected to the fourth support column;

[0016] A first spring is provided between the top of the support block and the top of the movable through hole, a hinge rope is provided at the bottom of the support block, a vertical hinge rope groove is provided at the bottom of the movable through hole, the movable through hole is connected with the vertical hinge rope groove, a horizontal hinge rope groove is provided at the bottom of the vertical hinge rope groove, the vertical hinge rope groove is connected with the horizontal hinge rope groove and is perpendicular to each other, the front end of the horizontal hinge rope groove passes through the front end of the second support column, a fixed pulley is installed at the connection between the vertical hinge rope groove and the horizontal hinge rope groove, the hinge rope extends along the vertical hinge rope groove and then turns through the fixed pulley, and then extends along the horizontal hinge rope groove, and the end of the hinge rope away from the support block is located in the tunnel.

[0017] Furthermore, the first telescopic support assembly includes a hydraulic rod, a first push rod is fixedly provided at a transmission end of the hydraulic rod, and a second telescopic rod is connected to the top of the first push rod;

[0018] The second telescopic rod comprises a plurality of tube columns, each of which is symmetrically provided with a first slide rail on the inner wall thereof, a first limit groove being provided near the top of the first slide rail, a baffle being provided at the bottom of the first slide rail, a self-resetting ball matching the first limit groove being provided at the bottom of the outer wall of each tube column, and the plurality of tube columns are sleeved with each other under the action of the first slide rail and the self-resetting ball;

[0019] An opening is provided at the bottom of each section of the pipe column, the first push rod is inserted into the opening, the top of the first push rod is fixedly connected to the bottom of the innermost pipe column, and the inflatable tarpaulin is fixedly connected to the end of the innermost pipe column.

[0020] Furthermore, the second telescopic support assembly and the third telescopic support assembly have the same structure as the first telescopic support assembly, and a fifth support column is fixedly provided on the top of the second support column, the second telescopic support assembly is installed in the fifth support column, and the top of the second telescopic support assembly passes through the fifth support column.

[0021] Furthermore, the inflatable tarpaulin comprises an inner layer and an outer layer, an air cavity is formed between the inner layer and the outer layer, and a flexible protective plate is fixedly provided on the outside of the outer layer; the self-sealing component is located between the inner layer and the outer layer;

[0022] The self-sealing component comprises a sealing seat, the sealing seat is located between the inner layer and the outer layer, an annular mounting disc is provided on the inner side of the sealing seat, an extrusion plate is provided on the inner side of the mounting disc, and the extrusion plate is made of elastic material;

[0023] An inflation tube is passed through the sealing seat, and inflation branches are provided on the left and right sides of the part of the inflation tube located in the inflatable tarpaulin, and the two inflation branches pass through the mounting plate; a first sealing plate is provided between the extrusion plate and the sealing seat, and a first sealing gasket is installed at the bottom of the first sealing plate, and the first sealing gasket is located at the top of the inflation tube, and the diameter of the first sealing gasket is larger than the outer diameter of the inflation tube; a second push rod is fixedly provided at the bottom of the first sealing gasket, and a second sealing plate is fixedly provided at the bottom of the second push rod, and the second sealing plate is located in the inflation tube, and the second sealing plate is slidingly and sealingly connected to the inner side wall of the inflation tube; a limiting assembly is also provided between the first sealing plate and the sealing seat.

[0024] Furthermore, the limit assembly includes a limit rod fixed at the bottom of the first sealing plate, the bottom of the limit rod passes through the sealing seat, and the part of the limit rod located on the outside of the sealing seat is threadedly connected to the limit nut; a second spring is also provided between the first sealing plate and the inflation branch pipe, and the second spring is sleeved outside the limit rod.

[0025] Furthermore, the spring buffer includes a buffer spring, a piston rod, a piston, a cylinder cover, an end support, a fixed end and a cylinder body, wherein a cylinder cover is provided on the top of the cylinder body; the fixed end is connected to the top of the vertical support, a piston rod is provided on the top of the fixed end, the piston rod passes through the bottom and the cylinder cover of the cylinder body, and an end support is provided on the top of the piston rod; a piston is provided on the outer sleeve of the piston rod, and the piston is located in the cylinder body; a buffer spring is provided between the piston and the bottom of the cylinder body.

[0026] Furthermore, a construction method for a device for preventing the collapse of a top unstable exposed karst cave during tunnel construction is characterized in that it comprises the following steps:

[0027] Step 1: When a karst cave is exposed at the top of the excavated tunnel, vertical support is first applied from the tunnel face;

[0028] Step 2: Install a spring buffer on the top of each vertical support as a buffer device;

[0029] Step 3: Install the inflatable tarpaulin and height adjustment components on the arch support to facilitate later support;

[0030] Step 4: Clean the cave, insert the arch support into the cave along the designed top surface of the tunnel, connect the arch support with the top of the spring buffer, and form preliminary protection for the area below the cave;

[0031] Step 5: After the arch support is installed, the inflatable tarpaulin is erected through the height adjustment assembly to contact the surface of the cave;

[0032] Step 6: Inflate the inflatable tarpaulin so that it fits the surface of the cave completely. The self-sealing component seals the inflation port and the overall installation is completed.

[0033] Step 7: Grout the cavity between the inflatable tarpaulin and the arch support.

[0034] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention has the following improvements:

[0035] 1. The present invention adopts a structure combining vertical support and arch support, which can support the top of the cave and prevent accidents caused by cave collapse; an inflatable tarpaulin is arranged on the arch support, and the inflatable tarpaulin can be deformed along with the shape of the top of the cave in the inflated state, and fits closely with the top of the cave, so that the slurry can fill the gaps in the cave during grouting, and the support effect is better.

[0036] 2. The present invention is provided with a self-sealing component at the inflation port of the inflatable tarpaulin. When the inflatable tarpaulin is inflated through the inflation port, as the volume of gas in the air cavity increases, the extrusion plate will be pushed downward to squeeze the first sealing plate, and the first sealing plate will then push the second sealing plate to move in the inflation tube; when the top of the inflation tube is sealed with the first sealing pad, the second sealing plate moves to the bottom of the inflation branch tube in the inflation tube, and the first sealing plate and the second sealing plate seal the top of the inflation tube and the inflation branch tube respectively, so that the gas cannot enter the inflatable tarpaulin, and the inflation port of the inflatable tarpaulin can be sealed to achieve the self-sealing effect of the inflatable tarpaulin; the first sealing plate will drive the limit rod to move downward during the downward movement, and when the first sealing plate seals the top of the inflation tube, the limit rod is fixed with a limit nut, so that the first sealing plate can be loosened to affect the sealing effect. The self-sealing component of the present invention is easy to operate and has good sealing performance.

[0037] 3. The height adjustment assembly in the present invention can adjust the height of the inflatable tarpaulin and support the inflatable tarpaulin. The first support column and the first telescopic support assembly installed therein can support the middle part of the inflatable tarpaulin. The triangular support assemblies on both sides of the first support column can support the top of the inflatable tarpaulin on both sides of the first support column and the side of the inflatable tarpaulin. The second support column, the third support column and the fourth support column in the triangular support assembly form a triangular structure. The stability of the triangular structure makes the triangular support assembly not easy to deform or shift during grouting, which can improve the overall stability.

[0038] 4. In the present invention, the angles of the third support column and the fourth support column can be adjusted so that they are located at the optimal supporting position. The angle adjustment of the third support column and the fourth support column is achieved by a hinge rope and a fixed pulley arranged in the second support column. The hinge rope only needs to be pulled from the outside to drive the synchronous adjustment of the angles of the third support column and the fourth support column through the support block, the first connecting rod and the second connecting rod. The operation is convenient, and the setting of the fixed pulley reduces the difficulty of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the positional relationship between the cave and the tunnel of the present invention.

[0040] Figure 2 It is the front view of the anti-collapse device structure of the present invention.

[0041] Figure 3 This is a front view of the height adjustment component structure of the present invention.

[0042] Figure 4 This is a front view of the internal structure of the second support column of the present invention.

[0043] Figure 5 It is a side view of the external structure of the second support column of the present invention.

[0044] Figure 6 This is a front view of the internal structure of the first support column of the present invention.

[0045] Figure 7 This is a front view of the first telescopic support assembly structure of the present invention.

[0046] Figure 8 It is a side view of the internal structure of the pipe column of the present invention.

[0047] Fig. 9 This is a cross-sectional structural diagram of the anti-collapse device of the present invention along the arrangement direction of the second support columns.

[0048] Fig.10 It is a side view of the internal structure of the second support column of the present invention.

[0049] Fig.11 It is a schematic diagram of the structure of the inflatable tarpaulin of the present invention.

[0050] Fig.12 It is a schematic structural diagram of the self-sealing component of the present invention in an unsealed state.

[0051] Fig.13 It is a schematic diagram of the sealing state structure of the self-sealing component of the present invention.

[0052] Fig.14 This is a top view of the mounting plate and extruded plate structure of the present invention.

[0053] Fig.15 It is a schematic diagram of the structure of the spring buffer of the present invention.

[0054] Among them: 1-tunnel, 2-cave, 3-vertical support, 4-arch support, 5-spring buffer, 501-buffer spring, 502-piston rod, 503-piston, 504-cylinder head, 505-end support, 506-fixed end, 507-cylinder body, 6-inflatable tarpaulin, 601-inner layer, 602-outer layer, 603-air cavity, 604-protection plate, 7-first support column, 701-first slide groove, 702-first slider, 8-first telescopic support assembly, 801-hydraulic rod, 802-first push rod, 803-second telescopic rod, 8031-pipe column, 8032-first slide rail, 8033-first limit groove, 8034-blocking piece, 8035-self-resetting ball, 9-second support column, 901-movable through hole, 902-vertical hinge rope groove, 903-horizontal hinge rope groove, 10-second telescopic support assembly, 11-third support column, 1101-third telescopic support assembly, 12-fourth support column, 13-first telescopic rod, 14-support block, 15-first connecting rod, 16-second connecting rod, 17-first spring, 18-hinge rope, 19-fixed pulley, 20-fifth support column, 21-sealing seat, 22-mounting plate, 23-extrusion plate, 24-inflating tube, 25-inflating branch pipe, 26-first sealing plate, 27-first sealing pad, 28-second push rod, 29-second sealing plate, 30-limiting rod, 31-limiting nut, 32-second spring. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0056] Refer to the attached Figure 1-15 The illustrated embodiment shows a device for preventing the collapse of a karst cave with unstable top exposure during tunnel construction, wherein the karst cave 2 is located at the top of the tunnel face 1, and the device for preventing the collapse comprises a vertical support 3 and an arch support 4, wherein the vertical support 3 is located in the tunnel 1 and is arranged along the tunnel face 1, and the vertical support 3 is made of a steel pipe and extends vertically upward from the ground;

[0057] The arch support 4 extends along the designed top surface of the tunnel 1, and the arch support 4 adopts a mesh. A spring buffer 5 is provided between the top of the vertical support 3 and the arch support 4;

[0058] An inflatable tarpaulin 6 is fixedly arranged between the two side edges of the arch support 4 , and a height adjustment component is arranged between the arch support 4 and the inflatable tarpaulin 6 ; and a self-sealing component is arranged on the inflatable tarpaulin 6 .

[0059] Specifically, the height adjustment assembly includes a plurality of first support columns 7 vertically arranged on the top of the arch support 4, and the plurality of first support columns 7 extend along the excavation direction of the tunnel 1. The top of the first support column 7 is an open structure, and each of the first support columns 7 is provided with a first telescopic support assembly 8, which passes through the top of the first support column 7, and the top of the first telescopic support assembly 8 is fixedly connected to the inflatable tarpaulin 6;

[0060] A triangular support assembly is slidably provided on the left and right sides of each of the first support columns 7, the top of the triangular support assembly and the end away from the first support column 7 are fixedly connected to the inflatable tarpaulin 6, and the end of the triangular support assembly close to the first support column 7 is slidably connected to the side surface corresponding to the first support column 7.

[0061] Furthermore, the triangular support assembly includes a second support column 9, the bottom of which is fixedly connected to the top of the arch support 4, and a second telescopic support assembly 10 is installed on the top of the second support column 9, and the top of the second telescopic support assembly 10 is fixedly connected to the inflatable tarpaulin 6;

[0062] The left and right sides of the second support column 9 are respectively hingedly connected with a third support column 11 and a fourth support column 12. The center of one end of the third support column 11 away from the second support column 9 is an open structure, and a third telescopic support assembly 1101 is installed in the open structure. The end of the third telescopic support assembly 1101 passes through the third support column 11, and the end of the third telescopic support assembly 1101 located outside the third support column 11 is also fixedly connected to the inflatable tarpaulin 6; the end of the fourth support column 12 away from the second support column 9 is fixedly provided with a first telescopic rod 13, and the first telescopic rod 13 can be an existing ordinary telescopic rod, which can be pulled or shortened under the action of external force. The end of the first telescopic rod 13 away from the fourth support column 12 is slidably connected to the first support column 7, and a first slide groove 701 is provided on the side of the first support column 7 close to the fourth support column 12. The first slide groove 701 extends along the up and down direction, and a first slider 702 matching it is provided in the first slide groove 701, and the end of the first telescopic rod 13 is hingedly connected to the first slider 702.

[0063] The second support column 9 is provided with a movable through hole 901 in the up and down direction, and the left and right sides of the movable through hole 901 respectively penetrate the left and right side surfaces of the second support column 9, and a support block 14 is slidably provided in the movable through hole 901, and the two sides of the support block 14 are respectively hingedly connected with a first connecting rod 15 and a second connecting rod 16, one end of the first connecting rod 15 is hingedly connected to the support block 14, and the other end of the first connecting rod 15 is slidably connected to the third support column 11; one end of the second connecting rod 16 is also hingedly connected to the support block 14, and the other end of the second connecting rod 16 is slidably connected to the fourth support column 12; the sliding connection between the first connecting rod 15 and the third support column 11, and the sliding between the second connecting rod 16 and the fourth support column 12 are both slidably connected by the sliding connection method between the first telescopic rod 13 and the first support column 7 (including a slide groove and a slider, and the first connecting rod 15 and the second connecting rod 16 are both hingedly connected to the corresponding slider).

[0064] Furthermore, a first spring 17 is provided between the top of the support block 14 and the top of the movable through hole 901, a hinge rope 18 is provided at the bottom of the support block 14, a vertical hinge rope groove 902 is provided at the bottom of the movable through hole 901, the movable through hole 901 is connected to the vertical hinge rope groove 902, the bottom of the vertical hinge rope groove 902 is connected to a horizontal hinge rope groove 903, the vertical hinge rope groove 902 is connected to the horizontal hinge rope groove 903 and is perpendicular to each other, the front end of the horizontal hinge rope groove 903 passes through the front end of the second support column 9, a fixed pulley 19 is installed at the connection between the vertical hinge rope groove 902 and the horizontal hinge rope groove 903, the hinge rope 18 extends along the vertical hinge rope groove 902 and then turns through the fixed pulley 19, and then extends along the horizontal hinge rope groove 903, and the end of the hinge rope 18 away from the support block 14 is located in the tunnel 1.

[0065] The working principle of the height adjustment assembly in the present invention is as follows: the first telescopic support assembly 8 in the first support column 7 adjusts the position of the inflatable tarpaulin 6 connected to the first telescopic support assembly 8 by telescoping; the second telescopic support assembly 10 installed on the top of the second support column 9 adjusts the position of the inflatable tarpaulin 6 connected to the second telescopic support assembly 8 by telescoping; in the excavated tunnel 1, the hinge rope 18 is pulled in the direction away from the tunnel face, and the force direction of the hinge rope 18 changes under the action of the fixed pulley 19, thereby pulling the support block 14 downward, and at the same time the first spring 17 is stretched, and the first spring 17 applies an upward pulling force to the support block 14 to prevent the support block 14 from moving downward by itself under the action of gravity. When the support block 14 moves downward, the first connecting rod 15 and the second connecting rod 16 respectively push the third support column 11 and the fourth support column 12 to change their angles. The third telescopic support assembly 1101 installed in the third support column 11 is extended and retracted to support the inflatable tarpaulin 6 from the tilted aspect. The first telescopic rod 13 at the end of the fourth support column 12 moves up and down along the side of the first support column 7. A triangular structure is formed between the second support column 9, the third support column 11 and the fourth support column 12, which has better stability and is not prone to shaking or shifting during grouting after the support is completed, thereby providing better support effect.

[0066] Further, the first telescopic support assembly 8 includes a hydraulic rod 801, the hydraulic rod 801 is installed in the opening of the first telescopic support assembly 8, a first push rod 802 is fixed to the transmission end of the hydraulic rod 801, and a second telescopic rod 803 is connected to the top of the first push rod 802;

[0067] The second telescopic rod 803 is formed by sleeves of multiple sections of pipe columns 8031. The pipe column 8031 ​​sleeved in the innermost layer has the smallest diameter, and the diameter of the pipe column 8031 ​​increases as it goes outward. The end of the innermost pipe column 8031 ​​is fixed to the inflatable tarpaulin 6. Two first slide rails 8032 are symmetrically welded on the inner wall of each section of the pipe column 8031. A baffle 8034 is provided at the bottom of the first slide rail 8032. The baffle 8034 and the first slide rail 8032 are integrally formed. A first limiting groove 8033 is provided at a position near the top of the first slide rail 8032. A self-resetting ball 8035 corresponding to the first limiting groove 8033 is provided at the bottom of the outer wall of each section of the pipe column 8031. An opening is provided at the center of the bottom of each section of the pipe column 8031. The first push rod 802 is inserted into the opening. The top of the first push rod 802 is welded to the bottom of the innermost pipe column 8031. The self-resetting ball 8035 is an elastic ball with a spring arranged inside the ball. The spring is compressed under the squeezing action of the first slide rail 8032, and the ball is squeezed in the slide rail under the action of the slide rail and the spring. When the self-resetting ball 8035 moves to the first limiting groove 8033, the spring is no longer affected by the slide rail, and the spring stretches while pushing the ball to be stuck in the first limiting groove 8033.

[0068] When not in use, the self-resetting ball 8035 is compressed in the first slide rail 8032 and blocked by the blocking piece 8034 at the bottom of the first slide rail 8032 , so that the inner tube column 8031 ​​is sleeved in the outer tube column 8031 ​​. When in use, the transmission end of the hydraulic rod 801 pushes the first push rod 802 to move upward, and the first push rod 802 drives the innermost pipe column 8031 ​​to move upward. When the innermost pipe column 8031 ​​moves upward, the self-resetting ball 8035 on its outer side wall moves in the first slide rail 8032 on the inner side wall of its outer pipe column 8031. When the self-resetting ball 8035 moves to the position of the first limiting groove 8033, the self-resetting ball 8035 is stuck in the first limiting groove 8033 and cannot move further. Under the continued action of the hydraulic rod 801, the innermost pipe column 8031 ​​drives the outer pipe column 8031 ​​to move upward together through the interaction between the self-resetting ball 8035 and the first limiting groove 8033. The principle of upward movement is the same as the movement principle of the innermost pipe column 8031, until the top of the innermost pipe column 8031 ​​reaches the top of the cave 2, and the hydraulic rod 801 stops working. Since the top surface of the cave 2 is uneven, the corresponding telescopic support components at different positions can be extended to different lengths, so that the inflatable tarpaulin 6 can contact the top of the cave 2 at different positions. At the same time, the entire height adjustment component can also further support the top of the cave 2.

[0069] In the present invention, the second telescopic support assembly 10 and the third telescopic support assembly 1101 have the same structure as the first telescopic support assembly 8, and a fifth support column 20 is fixedly provided on the top of the second support column 9, and the top of the fifth support column 20 is also an open structure. The second telescopic support assembly 10 is installed in the opening structure of the fifth support column 20, and the top of the second telescopic support assembly 10 passes through the fifth support column 20 and is fixedly connected to the inflatable tarpaulin 6.

[0070] Furthermore, the inflatable tarpaulin 6 includes an inner layer 601 and an outer layer 602, an air cavity 603 is formed between the inner layer 601 and the outer layer 602, a flexible protective plate 604 is fixedly arranged outside the outer layer 602, so as to prevent the outer layer 602 from being damaged by the uneven top surface of the cave 2, and the self-sealing component is located between the inner layer 601 and the outer layer 602;

[0071] The self-sealing component includes a sealing seat 21, which is located between the inner layer 601 and the outer layer 602. An annular mounting plate 22 is also provided on the inner side of the sealing seat 21, and an extrusion plate 23 is provided on the inner side of the mounting plate 22. The extrusion plate 23 is made of elastic material. The mounting plate 22 and the extrusion plate 23 separate the inflatable tarpaulin 6 into two parts, one part is the space where the sealing seat 21 is located, and the other part is the air cavity 603. When the inflatable tarpaulin 6 is inflated, the air cavity 603 on the inner side of the mounting plate 22 is actually inflated.

[0072] An inflation tube 24 is provided through the sealing seat 21, one end of the inflation tube 24 is located on the inner side of the sealing seat 21, and the other end is located outside the sealing seat 21, which can be connected to an inflation tube and inflation equipment in the outside. An inflation branch tube 25 is provided on both sides of the part of the inflation tube 24 located in the inflatable tarpaulin 6, and both inflation branch tubes 25 pass through the mounting plate 22; a first sealing plate 26 is provided between the extrusion plate 23 and the sealing seat 21, a first sealing pad 27 is installed at the bottom of the first sealing plate 26, the first sealing pad 27 is located at the top of the inflation tube 24, and the diameter of the first sealing pad 27 is larger than the outer diameter of the inflation tube 24; a second push rod 28 is fixedly provided at the bottom of the first sealing pad 27, a second sealing plate 29 is fixedly provided at the bottom of the second push rod 28, the second sealing plate 29 is located in the inflation tube 24, and the second sealing plate 29 is slidingly sealed and connected to the inner side wall of the inflation tube 24; a limiting component is also provided between the first sealing plate 26 and the sealing seat 21. When the inflatable tarpaulin 6 is not inflated, the second sealing plate 29 is located above the inflatable branch pipe 25 to seal the top of the inflatable pipe 24. After the gas passes through the inflatable pipe 24, it can only enter the air cavity 603 from the inflatable branch pipe 25. As the gas in the air cavity 603 is filled with gas, the gas squeezes the squeezing plate 23 to deform, thereby squeezing the first sealing plate 26 downward. During the downward movement of the first sealing plate 26, the second push rod 28 and the second sealing plate 29 are pushed downward. When the first sealing pad 27 at the bottom of the first sealing plate 26 seals the top of the inflatable pipe 24, the second sealing plate 29 moves to the bottom of the inflatable branch pipe 25 to seal the entire inflatable pipe 24 and the inflatable branch pipe 25. The first sealing pad 27 also forms a sealed environment between the inflatable branch pipe 25 and the top of the inflatable pipe 24, and the entire air cavity 603 is filled with gas. The position of the first sealing plate 26 can be limited by using a limit assembly to prevent the movement of the first sealing plate 26 from causing the inflatable tarpaulin 6 to leak and affect the support effect.

[0073] The limiting assembly includes a limiting rod 30 fixed to the bottom of the first sealing plate 26, the bottom of the limiting rod 30 passes through the sealing seat 21, and the part of the limiting rod 30 located outside the sealing seat 21 is threadedly connected to the limiting nut 31; a second spring 32 is also provided between the first sealing plate 26 and the inflation branch pipe 25, and the second spring 32 is sleeved outside the limiting rod 30. The first sealing plate 26 will drive the limiting rod 30 to move downward during the downward movement, and squeeze the second spring 32 at the same time. When the first sealing plate 26 moves to seal with the top of the inflation pipe 24, the limiting nut 31 is used to limit the limiting rod 30. Due to the setting of the second spring 32, the first sealing plate 26 cannot move downward without the action of external force, and the limiting effect of the limiting nut 31 makes the first sealing plate 26 unable to move upward without the action of external force, thereby enhancing the sealing effect.

[0074] Furthermore, the spring buffer 5 includes a buffer spring 501, a piston rod 502, a piston 503, a cylinder cover 504, an end support 505, a fixed end 506 and a cylinder body 507, wherein a cylinder cover 504 is provided on the top of the cylinder body 507; the fixed end 506 is connected to the top of the vertical support 3, a piston rod 502 is provided on the top of the fixed end 506, the piston rod 502 is a retractable rod-shaped structure, the piston rod 502 passes through the bottom of the cylinder body 507 and the cylinder cover 504, and an end support 505 is provided on the top of the piston rod 502; the end support 505 is fixedly connected to the arch support 4, a piston 503 is provided on the outer sleeve of the piston rod 502, and the piston 503 is located in the cylinder body 507; a buffer spring 501 is provided between the piston 503 and the bottom of the cylinder body 507. The spring buffer 5 in the present invention has the same structure as the existing spring buffer, that is, the spring buffer in the prior art can be used, and its specific structure and working principle are not described in detail in the present invention.

[0075] Furthermore, a construction method of a top unstable exposed cave anti-collapse device during tunnel construction comprises the following steps:

[0076] Step 1: When the top of the excavated tunnel encounters a karst cave 2, vertical support 3 is first applied from the tunnel face 1;

[0077] Step 2: Install a spring buffer 5 on the top of each vertical support 3 as a buffer device;

[0078] Step 3: Install the inflatable tarpaulin 6 and the height adjustment assembly on the arch support 4 to facilitate later support;

[0079] Step 4: Clean the inside of the cave 2, insert the arch support 4 into the cave 2 along the designed top surface of the tunnel 1, connect the arch support 4 with the top of the spring buffer 5, and form a preliminary protection for the area below the cave 2;

[0080] Step 5: After the arch support 4 is installed, the inflatable tarpaulin 6 is erected through the height adjustment component to contact the surface of the cave 2;

[0081] Step 6: Inflate the inflatable tarpaulin 6 so that the inflatable tarpaulin 6 is completely in contact with the surface of the cave 2, and the self-sealing component seals the inflation port, and the overall installation is completed;

[0082] Step 7: Grouting is performed on the cavity between the inflatable tarpaulin 6 and the arch support 4.

[0083] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A device for preventing the collapse of a karst cave with unstable top exposure during tunnel construction, wherein the karst cave (2) is located at the top of the tunnel (1) face, and is characterized by: The anti-collapse device comprises a vertical support (3) and an arch support (4), wherein the vertical support (3) is located in the tunnel (1), and the vertical support (3) is arranged along the tunnel face of the tunnel (1); The arch support (4) extends along the designed top surface of the tunnel (1), and a spring buffer (5) is provided between the top of the vertical support (3) and the arch support (4); An inflatable tarpaulin (6) is fixedly arranged between the two side edges of the arch support (4), and a height adjustment component is arranged between the arch support (4) and the inflatable tarpaulin (6); a self-sealing component is arranged on the inflatable tarpaulin (6); The height adjustment assembly comprises a plurality of first support columns (7) vertically arranged at the top of the arch support (4), each of the first support columns (7) being provided with a first telescopic support assembly (8), the first telescopic support assembly (8) penetrating the top of the first support column (7), and the top of the first telescopic support assembly (8) being fixedly connected to the inflatable tarpaulin (6); A triangular support assembly is slidably provided on the left and right sides of each first support column (7), the top of the triangular support assembly and the end away from the first support column (7) are fixedly connected to the inflatable tarpaulin (6), and the end of the triangular support assembly close to the first support column (7) is slidably connected to the side surface corresponding to the first support column (7); The triangular support assembly comprises a second support column (9), the bottom of the second support column (9) is fixedly connected to the top of the arch support (4), the top of the second support column (9) is provided with a second telescopic support assembly (10), and the top of the second telescopic support assembly (10) is fixedly connected to the inflatable tarpaulin (6); The left and right sides of the second support column (9) are movably connected to a third support column (11) and a fourth support column (12), respectively; a third telescopic support assembly (1101) is arranged inside the third support column (11); an end of the third telescopic support assembly (1101) passes through the third support column (11), and an end of the third telescopic support assembly (1101) located outside the third support column (11) is also fixedly connected to the inflatable tarpaulin (6); a first telescopic rod (13) is fixedly arranged at an end of the fourth support column (12) away from the second support column (9); an end of the first telescopic rod (13) away from the fourth support column (12) is slidably connected to the first support column (7).

2. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 1, characterized in that: The second support column (9) is provided with a movable through hole (901) in the up-and-down direction, a support block (14) is slidably provided in the movable through hole (901), a first connecting rod (15) and a second connecting rod (16) are movably provided on both sides of the support block (14), one end of the first connecting rod (15) is movably connected to the support block (14), and the other end of the first connecting rod (15) is slidably connected to the third support column (11); one end of the second connecting rod (16) is also movably connected to the support block (14), and the other end of the second connecting rod (16) is slidably connected to the fourth support column (12); A first spring (17) is provided between the top of the support block (14) and the top of the movable through hole (901); a hinge rope (18) is provided at the bottom of the support block (14); a vertical hinge rope groove (902) is provided at the bottom of the movable through hole (901); the movable through hole (901) is connected to the vertical hinge rope groove (902); a horizontal hinge rope groove (903) is provided at the bottom of the vertical hinge rope groove (902); the vertical hinge rope groove (902) is connected to the horizontal hinge rope groove (903) The two support blocks (14) are connected and perpendicular to each other, the front end of the horizontal rope groove (903) passes through the front end of the second support column (9), a fixed pulley (19) is installed at the connection between the vertical rope groove (902) and the horizontal rope groove (903), the rope (18) extends along the vertical rope groove (902), turns through the fixed pulley (19), and then extends along the horizontal rope groove (903), and the end of the rope (18) away from the support block (14) is located in the tunnel (1).

3. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 2, characterized in that: The first telescopic support assembly (8) comprises a hydraulic rod (801), a first push rod (802) is fixedly provided at the transmission end of the hydraulic rod (801), and a second telescopic rod (803) is connected to the top of the first push rod (802); The second telescopic rod (803) comprises a plurality of tube columns (8031), each of which is symmetrically provided with a first slide rail (8032) on its inner wall, the first slide rail (8032) is provided with a first limiting groove (8033) near the top, the bottom of the first slide rail (8032) is provided with a blocking sheet (8034), the bottom of the outer wall of each tube column (8031) is provided with a self-resetting ball (8035) matching the first limiting groove (8033), and the plurality of tube columns (8031) are mutually sleeved under the action of the first slide rail (8032) and the self-resetting ball (8035); An opening is provided at the bottom of each section of the pipe column (8031), the first push rod (802) is inserted into the opening, and the top of the first push rod (802) is fixedly connected to the bottom of the innermost pipe column (8031), and the inflatable tarpaulin (6) is fixedly connected to the end of the innermost pipe column (8031).

4. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 3, characterized in that: The second telescopic support assembly (10) and the third telescopic support assembly (1101) both have the same structure as the first telescopic support assembly (8), and a fifth support column (20) is fixedly arranged on the top of the second support column (9), the second telescopic support assembly (10) is installed in the fifth support column (20), and the top of the second telescopic support assembly (10) passes through the fifth support column (20).

5. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 1, characterized in that: The inflatable tarpaulin (6) comprises an inner layer (601) and an outer layer (602), an air cavity (603) is formed between the inner layer (601) and the outer layer (602), and a flexible protective plate (604) is fixedly provided on the outside of the outer layer (602); the self-sealing component is located between the inner layer (601) and the outer layer (602); The self-sealing component comprises a sealing seat (21), the sealing seat (21) being located between the inner layer (601) and the outer layer (602), an annular mounting plate (22) being provided on the inner side of the sealing seat (21), an extrusion plate (23) being provided on the inner side of the mounting plate (22), and the extrusion plate (23) being made of an elastic material; An inflation tube (24) is provided through the sealing seat (21), and inflation branches (25) are provided on the left and right sides of the portion of the inflation tube (24) located inside the inflatable tarpaulin (6), and the two inflation branches (25) both pass through the mounting plate (22); a first sealing plate (26) is provided between the extrusion plate (23) and the sealing seat (21), and a first sealing pad (27) is installed at the bottom of the first sealing plate (26), and the first sealing pad (27) is located at the top of the inflation tube (24). The first sealing pad (27) is provided with a second push rod (28) fixedly disposed at the bottom of the first sealing pad (27), and a second sealing plate (29) fixedly disposed at the bottom of the second push rod (28). The second sealing plate (29) is located in the inflation tube (24), and the second sealing plate (29) is slidably sealedly connected to the inner side wall of the inflation tube (24). A limiter assembly is also provided between the first sealing plate (26) and the sealing seat (21).

6. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 5, characterized in that: The limiting assembly comprises a limiting rod (30) fixedly mounted on the bottom of the first sealing plate (26), the bottom of the limiting rod (30) passing through the sealing seat (21), and the portion of the limiting rod (30) located outside the sealing seat (21) is threadedly connected to the limiting nut (31); a second spring (32) is also provided between the first sealing plate (26) and the inflation branch pipe (25), and the second spring (32) is sleeved outside the limiting rod (30).

7. The device for preventing the top of unstable exposed karst cave from collapsing during tunnel construction according to claim 1, characterized in that: The spring buffer (5) comprises a buffer spring (501), a piston rod (502), a piston (503), a cylinder cover (504), an end support (505), a fixed end (506) and a cylinder body (507), wherein the cylinder cover (504) is provided at the top of the cylinder body (507); the fixed end (506) is connected to the top of the vertical support (3), a piston rod (502) is provided at the top of the fixed end (506), the piston rod (502) passes through the bottom of the cylinder body (507) and the cylinder cover (504), and an end support (505) is provided at the top of the piston rod (502); a piston (503) is provided on the outer sleeve of the piston rod (502), and the piston (503) is located in the cylinder body (507); a buffer spring (501) is provided between the piston (503) and the bottom of the cylinder body (507).

8. A construction method for a device for preventing top unstable exposed karst caves from collapsing during tunnel construction as claimed in any one of claims 1 to 7, characterized in that: The following steps are included: Step 1: When a karst cave (2) is exposed at the top of the excavated tunnel, vertical support (3) is first applied from the tunnel face (1); Step 2: Install a spring buffer (5) on the top of each vertical support (3) as a buffer device; Step 3: Install the inflatable tarpaulin (6) and the height adjustment assembly on the arch support (4) to facilitate later support; Step 4: Clean the inside of the cave (2), insert the arch support (4) into the cave (2) along the designed top surface of the tunnel (1), connect the arch support (4) to the top of the spring buffer (5), and form preliminary protection for the area below the cave (2); Step 5: After the arch support (4) is installed, the inflatable tarpaulin (6) is erected through the height adjustment component to contact the surface of the cave (2); Step 6: Inflate the inflatable tarpaulin (6) so that the inflatable tarpaulin (6) is completely in contact with the surface of the cave (2), and the self-sealing component seals the inflation port, and the overall installation is completed; Step 7: Grouting is performed on the cavity between the inflatable tarpaulin (6) and the arch support (4).

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