Tunnel base soil body active drainage system device and method based on drainage nails

Abstract

The invention discloses a tunnel base soil body active drainage system device and method based on drainage nails, and relates to the technical field of tunnel construction. The device comprises capillary adsorption tube wells, side ditches and a pumping drainage device, the capillary adsorption tube wells are arranged on the two sides of the bottom of a tunnel, and the multiple capillary adsorption tube wells are arranged in the longitudinal direction of the tunnel; each capillary adsorption tube well is arranged in the vertical direction and extends into a base soil body below a tunnel bottom, each capillary adsorption tube well comprises a waterproof tube section, a water seepage tube section and a bottom precipitation tube section which are sequentially arranged, and every two adjacent tube sections are connected through a plugging connector. The side ditches are arranged on the two sides of the railway ballast and used for gathering and discharging water in the capillary adsorption tube wells. And the pumping and draining device is used for pumping and draining water in the capillary adsorption tube well into the side ditch. A natural filter layer can be formed under the capillary action of the water seepage pipe section, silt is effectively prevented from inrush, and therefore the method is suitable for long-term water pumping and drainage construction in the heavy haul railway base operation period, and frequent pipe well cleaning does not need to be carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a device and method for active drainage system of tunnel base soil based on drainage nails. Background Art

[0002] The driving process of heavy-duty railway tunnels is very strict. If water accumulates in the rock and soil at the bottom of the tunnel, the railway roadbed will overflow under large vibration loads, polluting the roadbed material, reducing the structural elasticity, and may cause the track geometry to become unstable, seriously threatening driving safety. In order to achieve stable operation of heavy-duty railways, traditional tunnel bottoms / roadbeds usually use passive drainage or active pumping methods. Passive drainage relies on the deadweight of laying blind pipes, PVC perforated pipes wrapped with geotextiles, etc. to discharge water, while active drainage involves laying precipitation wells / pipe wells, setting filter pipes / filter layers, and pumping groundwater with the help of pumping facilities / water adsorption devices. However, during the long-term pumping and drainage process, the traditional pumping and drainage mechanism will cause soil particles to sink and enter the drainage channel under water pressure and deadweight. Some particles will accumulate in the drainage holes, causing drainage blockage, and then completely lose the drainage function in a short period of time.

[0003] In order to solve the blockage problem caused by traditional long-term drainage, scholars have proposed a new active drainage structure of drainage nails in recent years. It uses capillary water pressure to adsorb pore water in the soil to control the soil saturation, and in the process of adsorbing pore water, a natural overhead layer and filter layer can be formed on the outside of the pipe, thereby preventing soil particles from infiltrating into the drainage channel. However, since the base of the heavy-duty railway tunnel is in the form of a bottom-laying structure, that is, the upper part of the arch foot is in the form of a closed 3 / 4 circular ring, and the lower part adopts a bottom-laying bottom plate and roadbed. However, due to its special annular cylindrical closed structure, the drainage nails need to be set at a certain upward angle to facilitate the free sliding of the water body, and it is difficult to discharge the water body at the bottom of the tunnel structure by relying on its own weight like an open-air foundation.

[0004] Therefore, in view of the shortcomings of the above-mentioned background technology, the present invention proposes an active drainage system device and method for tunnel base soil based on drainage nails, which is used to control the saturation of the base soil under the bottom of the heavy-load railway tunnel section and discharge the base disaster-causing water. Summary of the invention

[0005] The purpose of the present invention is to provide a tunnel base soil active drainage system device and method based on drainage nails to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides a tunnel base soil active drainage system device based on drainage nails, comprising:

[0007] A plurality of capillary adsorption tube wells, wherein the capillary adsorption tube wells are arranged on both sides of the tunnel paving bottom, and the plurality of capillary adsorption tube wells are arranged in the longitudinal direction of the tunnel; a single capillary adsorption tube well is arranged in the vertical direction and extends into the base soil below the tunnel paving bottom, and the capillary adsorption tube well comprises an impermeable pipe section, a seepage pipe section and a bottom sedimentation pipe section arranged in sequence from top to bottom, and two adjacent pipe sections are connected by a plugging joint;

[0008] Side ditches are arranged on both sides of the ballast above the tunnel paving bottom, and are used to collect and discharge water in the capillary adsorption tube well;

[0009] A pumping device is used to pump water in the capillary adsorption tube well into the side ditch.

[0010] Preferably, a compressible sealing strip is provided on the outer wall of the watertight pipe section, and the watertight pipe section and the tunnel floor are sealed by the compressible sealing strip.

[0011] Preferably, the seepage pipe section comprises a plurality of capillary tube sections, a gap is formed between two adjacent capillary tube sections through a fulcrum, and two adjacent capillary tube sections are connected and fixed through a drainage nail joint.

[0012] Preferably, the capillary tube section includes an inner PVC pipe and a capillary drainage belt arranged on the outer side of the PVC pipe, and a plurality of capillary grooves are formed on a side of the capillary drainage belt away from the PVC pipe, and the capillary grooves are arranged along the axial direction of the PVC pipe.

[0013] Preferably, the length of a single capillary segment is 1m to 2m, and the inner diameter is 75mm.

[0014] Preferably, the watertight pipe section and the bottom sedimentation pipe section are both high-rigidity stainless steel pipes, and the inner diameter of the watertight pipe section is 75 mm.

[0015] Preferably, a manhole cover is installed on the top of the watertight pipe section.

[0016] Preferably, the pumping and drainage device includes a pumping pipe arranged in the capillary adsorption tube well, a plurality of the pumping pipes are connected to a pump via a connecting pipe, the water outlet of the pump is connected to a drainage pipe, and the end of the drainage pipe is arranged in the side ditch.

[0017] Preferably, the pumping device further includes a liquid level sensor, which is used to detect the water level in the bottom sedimentation pipe section; a controller is provided in the water pump, and the liquid level sensor and the water pump are both electrically connected to the controller.

[0018] A construction method of a tunnel base soil active drainage system device based on drainage nails, comprising the following steps:

[0019] S1. Determine the construction time and start drilling construction in the dry season when the rainfall is less than 150 mm and there is no significant sudden water inrush at the bottom of the tunnel;

[0020] S2. Before drilling, wellbore positioning is performed;

[0021] S3. After the wellbore is located, the ballast at the wellbore location is removed and core drilling is carried out. The depth of the drilling into the base soil shall not exceed 5m;

[0022] S4. After the drilling is completed, the borehole is cleaned and a capillary adsorption tube well is immediately installed. The length of the impermeable tube section of the capillary adsorption tube well protruding from the ballast is 20 cm to 30 cm;

[0023] S5. Install manhole cover.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] The tunnel base soil active drainage system device based on drainage nails provided by the present invention is based on the mature drainage structure of drainage nail details to construct a drainage top capillary adsorption drainage system suitable for the base rock and soil of heavy-duty railway tunnel roadbed, so as to achieve long-term continuous saturation control and pore water adsorption and drainage of the base slag and rock and soil of the heavy-duty railway tunnel during operation, prevent oversaturation and soil from affecting driving safety, and alleviate the roadbed diseases caused by oversaturation of soil in heavy-duty railway tunnel sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a cross-sectional schematic diagram of a tunnel base soil active drainage system device based on drainage nails according to the present invention;

[0028] Figure 2 It is a schematic longitudinal section diagram of the tunnel base soil active drainage system device based on drainage nails of the present invention;

[0029] Figure 3 It is a structural schematic diagram of the water seepage pipe section of the present invention;

[0030] Figure 4 It is a schematic structural diagram of the capillary segment of the present invention;

[0031] In the figure: 1. capillary adsorption tube well; 2. tunnel bottom; 3. base soil; 4. side ditch; 5. ballast; 6. manhole cover; 7. pumping pipe; 8. pump; 9. drainage pipe; 10. liquid level sensor; 11. impermeable pipe section; 12. seepage pipe section; 13. bottom sedimentation pipe section; 14. plugging joint; 15. compressible sealing strip; 121. capillary tube section; 122. fulcrum; 123. gap; 124. drainage nail joint; 1211. PVC pipe; 1212. capillary drainage belt; 1213. capillary groove. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0033] like Figures 1 to 4 As shown, the present invention provides a tunnel base soil active drainage system device based on drainage nails, comprising:

[0034] A plurality of capillary adsorption tube wells 1 are arranged on both sides of the tunnel paving 2, and the plurality of capillary adsorption tube wells 1 are arranged in the longitudinal direction of the tunnel; a single capillary adsorption tube well 1 is arranged in the vertical direction and extends into the base soil 3 below the tunnel paving 2, and the capillary adsorption tube well 1 includes an impermeable pipe section 11, a seepage pipe section 12 and a bottom sedimentation pipe section 13 arranged in sequence from top to bottom, and two adjacent pipe sections are connected by a plugging joint 14;

[0035] Side ditches 4 are arranged on both sides of the ballast 5 above the tunnel floor 2, and are used to collect and discharge water in the capillary adsorption tube well 1;

[0036] The pumping device is used to pump the water in the capillary adsorption tube well 1 into the side ditch 4.

[0037] The present invention can effectively prevent the recharge of deep pressurized water to the well point caused by external water level fluctuations by using the capillary principle, thereby reducing the safety risks to vehicles during the operation period. Moreover, the capillary action of the seepage pipe section 12 can form a natural filter layer, effectively preventing the influx of sediment, so that it is suitable for long-term drainage construction during the operation period of the heavy-duty railway base, without the need for frequent pipe well cleaning. In addition, the bottom sedimentation pipe section 13 can precipitate sand and soil particles that enter the inner side of the pipeline through adsorption, preventing soil particles from clogging the drainage device during the operation period.

[0038] According to a further optimized solution, a compressible sealing strip 15 is provided on the outer wall of the watertight pipe section 11 , and the watertight pipe section 11 and the tunnel floor 2 are sealed by the compressible sealing strip 15 .

[0039] The provision of the compressible sealing strip 15 can provide an extrusion sealing pressure between the concrete structure of the tunnel floor 2 and the impermeable pipe section 11, thereby controlling water seepage at the joint outside the well of the tunnel floor 2 under high water pressure.

[0040] According to a further optimized solution, the seepage pipe section 12 includes a plurality of capillary tube sections 121 , a gap 123 is formed between two adjacent capillary tube sections 121 through a fulcrum 122 , and two adjacent capillary tube sections 121 are connected and fixed by a drainage nail joint 124 .

[0041] The capillary segments 121 utilize capillary separation to transport water, and the water enters the inner side of the capillary segments 121 at the gaps 123 between the capillary segments 121 , so that the water can normally enter the interior of the capillary segments 121 while ensuring the connection of the capillary segments 121 .

[0042] According to a further optimization scheme, the capillary section 121 includes an inner PVC pipe 1211 and a capillary drainage belt 1212 arranged on the outer side of the PVC pipe 1211. A plurality of capillary grooves 1213 are provided on the side of the capillary drainage belt 1212 away from the PVC pipe 1211. The capillary grooves 1213 are arranged along the axial direction of the PVC pipe 1211.

[0043] The provision of the capillary drainage belt 1212 can form a natural filter layer outside the pipe well, effectively preventing the influx of silt, thereby reducing the frequency of cleaning the pipe well.

[0044] According to a further optimized solution, the length of a single capillary section 121 is 1 m to 2 m, and the inner diameter is 75 mm.

[0045] According to a further optimization scheme, the watertight pipe section 11 and the bottom sedimentation pipe section 13 are both high-rigidity stainless steel pipes, and the inner diameter of the watertight pipe section 11 is 75 mm.

[0046] To further optimize the solution, a manhole cover 6 is installed on the top of the impermeable pipe section 11 to achieve groundwater gas blocking in the non-drainage stage.

[0047] To further optimize the solution, the pumping and drainage device includes a pumping pipe 7 arranged in the capillary adsorption tube well 1, and multiple pumping pipes 7 are connected to a pumping pump 8 through a connecting pipe. The water outlet of the pumping pump 8 is connected to a drainage pipe 9, and the end of the drainage pipe 9 is arranged in the side ditch 4.

[0048] To further optimize the solution, the pumping device also includes a liquid level sensor 10, which is used to detect the water level in the bottom sedimentation pipe section 13; a controller is provided in the water pump 8, and the liquid level sensor 10 and the water pump 8 are both electrically connected to the controller.

[0049] The liquid level sensor 10 can continuously detect the water level of the bottom sedimentation pipe section 13. When the water level reaches a preset low point, the liquid level sensor 10 sends a signal to the water pump 8 to stop pumping water. When the water level returns to a certain height, the water pump 8 restarts to prevent the water pump 8 from running dry and being damaged.

[0050] A construction method of a tunnel base soil active drainage system device based on drainage nails, comprising the following steps:

[0051] S1. Determine the construction time and start drilling construction in the dry season when the rainfall is less than 150 mm and there is no significant sudden water inrush in the tunnel bottom 2;

[0052] S2. Before drilling, first carry out well positioning; for the leakage area, the wellbore is densely arranged, and the spacing on one side is about 2.0m. The specific spacing needs to be determined according to the local historical meteorology, rock and soil saturation control requirements, tunnel burial depth and water level, surrounding rock and soil and hydrogeological environment;

[0053] S3. After the well hole is located, first remove the ballast 5 at the drilling location until the concrete of the tunnel bottom 2 in the drilling area is exposed, then fix the drilling instrument, and use a diamond drill bit to drill the core. The depth of the core entering the base soil 3 should not exceed 5m, and the hole diameter should be slightly larger than 75mm to prevent the hole from collapsing. The specific depth parameters need to be determined in combination with the on-site geological conditions. After drilling, use a negative pressure adsorption device to clean the residue and debris and clean the hole until there is no obvious debris at the bottom of the hole, and then enter the capillary adsorption tube well 1 installation process;

[0054] S4. After the drilling is completed, the borehole is cleaned and the capillary adsorption tube well 1 is immediately installed. The capillary adsorption tube well 1 is vertically inserted into the well hole. During the installation process, the impermeable pipe section 11 of the capillary adsorption tube well 1 is knocked to press the entire capillary adsorption tube well 1 until the expandable compression rubber strip forms a close contact with the inner wall of the concrete borehole. The expandable compression rubber strip is compressed, so that the tunnel paving 2 can control the water seepage at the joint outside the well under high water pressure. The length of the impermeable pipe section 11 of the capillary adsorption tube well 1 protruding from the ballast 5 is 20cm to 30cm, so as to facilitate the drainage operation.

[0055] S5. Install the manhole cover 6 to seal off the underground water and gas in the non-drainage stage.

[0056] After the rainy season begins, the manhole cover 6 is opened, the drainage pipes 9 and the liquid level sensor 10 are installed, and the two are connected to the water pump 8 to start the saturation control of the rock and soil at the bottom of the tunnel.

[0057] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A tunnel base soil active drainage system device based on drainage nails, characterized in that: include: A plurality of capillary adsorption tube wells (1), wherein the capillary adsorption tube wells (1) are arranged on both sides of a tunnel floor (2), and the plurality of capillary adsorption tube wells (1) are arranged in the longitudinal direction of the tunnel; a single capillary adsorption tube well (1) is arranged in the vertical direction and extends into a base soil (3) below the tunnel floor (2); the capillary adsorption tube well (1) comprises a water-impermeable pipe section (11), a water seepage pipe section (12) and a bottom sedimentation pipe section (13) which are arranged in sequence from top to bottom, and two adjacent pipe sections are connected via a plugging joint (14); Side ditches (4), the side ditches (4) being arranged on both sides of the ballast (5) above the tunnel floor (2), the side ditches (4) being used to collect and discharge water in the capillary adsorption tube well (1); A pumping device is used to pump water in the capillary adsorption tube well (1) into the side ditch (4).

2. The tunnel base soil active drainage system device based on drainage nails according to claim 1 is characterized in that: A compressible sealing strip (15) is provided on the outer wall of the watertight pipe section (11), and the watertight pipe section (11) and the tunnel floor (2) are sealed by the compressible sealing strip (15).

3. The tunnel base soil active drainage system device based on drainage nails according to claim 1 is characterized in that: The water seepage pipe section (12) comprises a plurality of capillary tube sections (121), a gap (123) is formed between two adjacent capillary tube sections (121) via a fulcrum (122), and two adjacent capillary tube sections (121) are connected and fixed via a drainage nail joint (124).

4. The tunnel base soil active drainage system device based on drainage nails according to claim 3 is characterized in that: The capillary tube section (121) comprises an inner PVC pipe (1211) and a capillary drainage belt (1212) arranged on the outer side of the PVC pipe (1211); a plurality of capillary grooves (1213) are provided on a side of the capillary drainage belt (1212) away from the PVC pipe (1211); and the capillary grooves (1213) are arranged along the axial direction of the PVC pipe (1211).

5. The tunnel base soil active drainage system device based on drainage nails according to claim 3 is characterized in that: The length of a single capillary section (121) is 1m to 2m, and the inner diameter is 75mm.

6. The tunnel base soil active drainage system device based on drainage nails according to claim 5 is characterized in that: The water-impermeable pipe section (11) and the bottom sedimentation pipe section (13) are both high-rigidity stainless steel pipes, and the inner diameter of the water-impermeable pipe section (11) is 75 mm.

7. The tunnel base soil active drainage system device based on drainage nails according to claim 1 is characterized in that: A manhole cover (6) is installed on the top of the water-tight pipe section (11).

8. The tunnel base soil active drainage system device based on drainage nails according to claim 1 is characterized in that: The pumping and drainage device comprises a water pumping pipe (7) arranged in the capillary adsorption tube well (1); a plurality of the water pumping pipes (7) are connected to a water pump (8) via a connecting pipe; the water outlet end of the water pump (8) is connected to a drainage pipe (9); the end of the drainage pipe (9) is arranged in the side ditch (4).

9. The tunnel base soil active drainage system device based on drainage nails according to claim 8, characterized in that: The pumping device further comprises a liquid level sensor (10), wherein the liquid level sensor (10) is used to detect the water level in the bottom sedimentation pipe section (13); a controller is provided in the water pump (8), and the liquid level sensor (10) and the water pump (8) are both electrically connected to the controller.

10. A construction method for a tunnel base soil active drainage system device based on drainage nails according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Determine the construction time and start drilling construction in the dry season when the rainfall is less than 150 mm and when there is no significant sudden water inrush on the tunnel floor (2); S2. Before drilling, wellbore positioning is performed; S3, after the well hole is located, the ballast (5) at the well hole location is removed, and core drilling is performed, and the depth of the drilling into the base soil (3) does not exceed 5m; S4. After the drilling is completed, the borehole is cleaned and the capillary adsorption tube well (1) is immediately installed. The length of the impermeable pipe section (11) of the capillary adsorption tube well (1) protruding from the ballast (5) is 20 cm to 30 cm; S5. Install the manhole cover (6).

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