Drainage structure for long distance tunnels in deep water-rich fractured zones

Abstract

The present invention discloses a drainage structure for a long-distance tunnel in a deep-buried water-rich fractured zone. A first water retaining wall is arranged at a position close to the face of the outlet section of the horizontal guide. The lower part of the first water retaining wall is not sealed to form a water outlet. The surrounding rock between the face of the outlet section of the horizontal guide and the first water retaining wall is reinforced by anchor rods. A second water retaining wall is arranged on the side of the horizontal hole in the horizontal guide close to the outlet. A third water retaining wall is arranged on the side of the horizontal hole in the main hole close to the outlet. Drainage ditches are arranged on the left and right sides of the tunnel section between the first water retaining wall and the second water retaining wall and on the left and right sides of the horizontal hole. A drainage channel connected to a natural river ditch is built at the outlet of the horizontal hole. A drainage hole that penetrates the outlet section and the excavated section is drilled on the to-be-excavated section of the horizontal guide. It is specially used for rapid drainage of special tunnels that have not yet been penetrated, the length of the to-be-excavated section reaches more than 800 meters, the daily water inflow is large, and the outlet is below a residential area or factory area that is not suitable for drainage.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a drainage structure for a long tunnel in a deep-buried water-rich broken zone. Background Art

[0002] Horizontal directional drilling rigs were first used in the late 1970s. With the continuous improvement and perfection of technology and equipment, they are developing towards large-scale, miniaturized, hard rock operations, mechanical automation (including self-contained anchoring systems, automatic stacking and extraction of drill pipes, automatic lubrication of drill pipe connections, anti-electric shock systems and other automated operation functions), ultra-deep guidance monitoring, etc. At present, directional drilling is mainly used in pipeline laying. Directional drilling is used to cross obstacles including highways, high-speed railways, large rivers, reservoirs, ponds, swamps, etc. It has the characteristics of short construction period, little damage to the surface, and little pollution to the environment.

[0003] However, horizontal directional drilling has not yet been applied in the construction of long-distance, large-diameter tunnels. There is a lack of experience in terms of equipment tonnage selection, technical level of construction personnel, control of construction technology difficulty, and construction measures. However, with the increasing number of long and large tunnels in China, there are more and more cases where sudden water inrush accidents require drilling for drainage, and complex geological conditions are difficult to investigate. It is urgent to use directional drilling to drill holes in tunnels for drainage while exploring the geological conditions ahead, especially in the study of construction technology for crossing long tunnels.

[0004] like Figure 1 In the tunnel shown in the figure, water gushed out from the side wall of the excavated section of Pingdao 2. This sudden water gushing is rare in China, with the lowest water gushing amount in the tunnel being 6965m 3 / h, maximum 11631m 3 / h, average 9298m 3 / h, daily water inflow 169641m 3 / d~279144m 3 / d, with a total water inflow of 11.53 million m 3 (Including the amount of water in the tunnel). However, the tunnel has not been completed yet, and there are 952 meters between the inclined shaft and the exit section that have not been penetrated. The section to be excavated passes through the fault fracture zone 4. The main tunnel 1 is higher than the horizontal guide 2, and the main tunnel 1 and the horizontal guide 2 have a descending slope along the A direction. The water in the excavated section of the tunnel has flooded to the wellhead of the inclined shaft 5, and the fixed pumping station at the inclined shaft 5 cannot be used for pumping and drainage. In addition, there is a residential area below the exit of this long-distance tunnel. This sudden water influx is rare in China and has a great impact on the safety and construction period of the project. How to quickly discharge water in a short period of time and do a good job in the rescue work of the main project is urgent. Summary of the invention

[0005] The present invention aims to provide a drainage structure for a long tunnel in a deep-buried water-rich fractured zone, which is specially used for tunnels that have not yet been penetrated, the length of the section to be excavated reaches more than 800 meters, the daily water inflow is large, the water in the tunnel has flooded the wellhead of the inclined well, the pump station is unable to pump out water, the section to be excavated runs through the fault fractured zone, and the exit is below a residential area or factory area, etc., which are special tunnels that are not suitable for drainage.

[0006] To this end, the technical solution adopted by the present invention is: a drainage structure for a long-distance tunnel in a deeply buried water-rich fractured zone, including a main tunnel and a horizontal guide, both of which include an excavated section, a section to be excavated and an exit section; the main tunnel and the horizontal guide are connected by a number of transverse passages arranged at intervals along the length of the tunnel, the length of the section to be excavated of the horizontal guide reaches more than 800 meters, and the section to be excavated runs through the fault fractured zone, the main tunnel is higher than the horizontal guide, the main tunnel and the horizontal guide have a descending slope along the A direction, a transverse tunnel that runs through the main tunnel to the horizontal guide is arranged at the tunnel exit section, the water in the excavated section of the tunnel has flooded to the inclined shaft mouth, a first water retaining wall is arranged at a position close to the heading face of the exit section of the horizontal guide, and the first water retaining wall The lower part of the wall is not sealed to form a water outlet. The surrounding rock between the face of the exit section of the horizontal guide and the first water retaining wall is reinforced by anchor rods. A second water retaining wall is arranged on the side of the horizontal hole in the horizontal guide close to the exit, and a third water retaining wall is arranged on the side of the horizontal hole in the main tunnel close to the exit; drainage ditches are arranged on the left and right sides of the tunnel section between the first water retaining wall and the second water retaining wall and on the left and right sides of the horizontal hole between the second water retaining wall and the third water retaining wall. A drainage channel connected to the natural river ditch is built at the exit of the horizontal hole. A drainage hole that passes through the exit section and the excavated section is drilled on the section to be excavated of the horizontal guide, and the drainage hole is constructed by a horizontal directional drilling rig from the exit horizontal guide face to the long-mileage horizontal guide face.

[0007] As a preferred embodiment of the above scheme, at least two drainage holes are drilled from top to bottom along the height direction of the flat guide face.

[0008] More preferably, the diameter of the drain hole is 250 mm.

[0009] Beneficial effects of the present invention:

[0010] (1) Horizontal directional drilling, which is mainly used for laying pipelines, is used for tunnel drilling and drainage. Compared with ordinary horizontal drilling rigs that can only drill to a depth of more than 100 meters, horizontal directional drilling rigs can drill holes to a depth of 1,000 meters. With a large borehole diameter, they can quickly drill holes for drainage, solve the problem of tunnel flooding in a timely manner, and avoid project delays and safety hazards caused by sudden water inrush;

[0011] (2) When drilling with horizontal directional drilling, taking into account the special situation of long tunnels buried deep in water-rich broken zones, use the cross hole to enter and drill long holes from the horizontal guide outlet section for rapid water discharge;

[0012] (3) Since the water in the excavated section has flooded the inclined shaft mouth, a first water retaining wall is set at a position close to the horizontal guide outlet section, and the lower part of the first water retaining wall is not sealed to form a water outlet. A comprehensive measure of anchor rod reinforcement is taken for the surrounding rock between the horizontal guide outlet section and the first water retaining wall to ensure that the water pressure from the drill hole will not cause the face to collapse. The water with high impact force from the drill hole releases kinetic energy instantly under the action of the first water retaining wall and flows out along the water outlet at the lower part of the first water retaining wall, which will not affect the working drilling rig and will not affect the construction of the next drill hole;

[0013] (4) Add the second and third water retaining walls, set drainage ditches on the left and right sides of the tunnel section between the first and second water retaining walls and on the left and right sides of the transverse tunnel between the second and third water retaining walls, and build a drainage channel connected to the natural river ditch at the exit of the transverse tunnel, so that water can only flow through the drainage ditch of the transverse tunnel and then to the natural river ditch through the drainage channel, and will not flow out from the exit of the tunnel. Abandon the traditional way of draining water from the exit, cleverly use the transverse tunnel for drainage, and will not interfere with the lives of residents and factory operations at the exit. ;

[0014] (5) The method of reverse drilling from the exit section using a horizontal directional drill to quickly drain the water from the constructed section is shorter in construction period, lower in cost, and safer and more reliable than the traditional excavation drainage method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention.

[0016] Figure 2 This is the process flow chart of horizontal directional drilling construction.

[0017] Figure 3 Schematic diagram of water drainage during drilling of horizontal directional drilling rig.

[0018] Figure 4 Schematic diagram of the site layout of the horizontal directional drilling rig in the tunnel. DETAILED DESCRIPTION

[0019] The present invention will be further described below by way of embodiments and in conjunction with the accompanying drawings:

[0020] like Figure 1As shown, a main tunnel 1 and a horizontal guide 2 are set in a long-distance tunnel in a deep-buried water-rich fracture zone. Both the main tunnel 1 and the horizontal guide 2 include an excavated section, a section to be excavated, and an exit section. The main tunnel 1 and the horizontal guide 2 are connected by a number of transverse passages 3 arranged at intervals along the length of the tunnel. The length of the section to be excavated of the horizontal guide 2 is 952 meters, and the section to be excavated runs through the fault fracture zone 4, and the length of the fracture zone is 250 meters. The main tunnel 1 is higher than the horizontal guide 2. The main tunnel 1 and the horizontal guide 2 have a 1.1% descending slope along the A direction (as shown by the arrow in the figure). A horizontal tunnel 9 is set at the exit section of the tunnel, which runs through the main tunnel 1 to the horizontal guide 2. The water in the excavated section of the tunnel has flooded to the wellhead of the inclined shaft 5. The water in the tunnel is very deep, and the daily water inflow reaches tens of thousands of cubic meters. The pump station 5a at the wellhead of the inclined shaft can no longer perform normal pumping and drainage. Below the exit section of the tunnel is a residential area or factory area, and drainage is impossible.

[0021] A first water retaining wall 6 is provided at a position close to the exit section of the flat guide 2, and the lower part of the first water retaining wall 6 is not sealed to form a water outlet. The surrounding rock between the exit section of the flat guide 2 and the first water retaining wall 6 is reinforced by anchor rods. A second water retaining wall 7 is provided on the side of the horizontal hole 9 in the flat guide 2 close to the exit, and a third water retaining wall 8 is provided on the side of the horizontal hole 9 in the main tunnel 1 close to the exit; drainage ditches are provided on the left and right sides of the tunnel section between the first water retaining wall 6 and the second water retaining wall 7, and on the left and right sides of the horizontal hole between the second water retaining wall 7 and the third water retaining wall 8. A drainage channel connected to the natural river ditch is built at the exit of the horizontal hole 9, so that the water coming out of the drilled hole first flows out through the outlet below the first water retaining wall 6, and then flows into the natural river ditch through the drainage ditches on the left and right sides of the tunnel, the drainage ditches on the left and right sides of the horizontal hole, and the drainage channel. Before drilling, the drainage route is planned, anchor rod reinforcement and water retaining wall arrangement are carried out first.

[0022] A drainage hole is drilled on the section to be excavated of flat guide 2, which passes through the exit section and the excavated section. The drainage hole is drilled by a horizontal directional drilling rig from the exit flat guide heading face toward the long-mileage flat guide heading face.

[0023] The specific construction steps for drilling drainage holes using a horizontal directional drill are as follows:

[0024] The first step is to conduct on-site survey, site layout, guide line design and measurement and layout;

[0025] Horizontal directional drilling construction process flow chart Figure 1 Before the horizontal directional drilling rig enters the site, on-site survey, site layout, guide line design and measurement and layout are carried out to prepare for the subsequent horizontal directional drilling rig construction; Figure 1 , Figure 4 As shown, the tunnel between the first water retaining wall 6 and the second water retaining wall 7 is divided into six parts: a drilling rig operation area, a drill rod storage area, a pump station, a mud recovery area, a jet pump, and a bentonite storage area.

[0026] like Figure 3 As shown, no matter whether the horizontal guide to be traversed is a curved section or a straight section, it is best to design the guide line by straight drilling, and the drilling guide line design must be completed before the horizontal directional drilling rig is in place.

[0027] The drilling direction is determined by the coordinates of the horizontal guide exit section and the horizontal guide long mileage face, and the coordinates of the entry point, exit point and the horizontal distance between the two points are verified. The center axis is laid out according to the coordinates, and the placement of the horizontal directional drilling rig is determined to ensure that the center line of the drilling rig is in a straight line with the entry point and exit point. At the same time, ground beacon control piles are set, the relative coordinates of each ground beacon control pile are measured, and records are kept.

[0028] The second step is to put the drilling rig in place and test drill.

[0029] The horizontal directional drilling rig enters the exit section of the horizontal guide 2 through the horizontal hole 9 and is positioned near the first retaining wall 6. The drilling rig is set in the middle of the left and right. The angle between the drilling rig guide rail and the horizontal plane is 0.1-0.5° larger than the designed entry angle. The drilling rig is installed firmly and stably. After passing the inspection, the system is connected.

[0030] Before drilling, check whether the power supply of the horizontal directional drilling rig's guidance system, including the receiver, transmitter, and remote synchronous monitor, is intact; check whether the receiver and remote synchronous monitor channels match, and test the interference signal in the construction area to determine the appropriate transmission and reception frequencies.

[0031] Before drilling, prepare for the installation and commissioning of the drilling rig, and after trial drilling 1 to 2 drill rods, make sure that the system is operating normally.

[0032] Calibrate the steering parameters according to the operating procedures. To ensure the accuracy of the data, it is best to measure at different positions across the axis, and measure each position at least four times, compare and record them, and take the average of the effective values ​​as the steering value.

[0033] The third step is drilling with a drilling rig;

[0034] Before the formal drilling, install the non-magnetic drill collar, non-magnetic directional short section, non-magnetic deflection short section, and positioning adjustment piece in front of the drill rod, and then connect the drill bit.

[0035] Before drilling, clean the mud filter, flush the drill bit and its nozzle with mud, and test run the drill bit for no less than 15 minutes. Drilling should begin only after ensuring that all parts of the machine are operating normally and mud is flowing from the drill bit nozzle.

[0036] During the drilling process, the wired geomagnetic rod installed at the tail of the drill bit transmits data to a dedicated computer equipped with a data box. The operator compares the data with the design coordinates entered into the computer before drilling, and makes timely adjustments if any deviation occurs.

[0037] In case of abnormal mud pressure, timely analyze the drilling situation, withdraw several drill rods and adjust the drilling direction if necessary;

[0038] During the drilling process, the electrician should check and adjust the control line at any time to ensure that there are no kinks or damages to prevent signal transmission failure.

[0039] During the directional drilling process, strictly control the angle change and shorten the measurement interval. When encountering changes in the hardness of the formation, the parameter measurement interval must not exceed 2 meters. When adjusting the azimuth and inclination, leave a margin to avoid repeated adjustment of the angle due to excessive adjustment to prevent the formation of an "S" shaped trajectory.

[0040] Step 4: Quickly clean up and restore the site;

[0041] After the drilling construction is completed, the horizontal directional drilling rig leaves the tunnel through the horizontal tunnel 9, and promptly cleans up the remaining mud, additives and other materials on site to ensure that the drainage on site is pollution-free.

Claims

1. A drainage structure for a long-distance tunnel in a deep-buried, water-rich fractured zone, comprising a main tunnel (1) and a horizontal guide (2), wherein both the main tunnel (1) and the horizontal guide (2) include an excavated section, a section to be excavated and an exit section; the main tunnel (1) and the horizontal guide (2) are connected via a plurality of transverse passages (3) arranged at intervals along the length direction of the tunnel, the length of the section to be excavated of the horizontal guide (2) reaches more than 800 meters, and the section to be excavated runs through a fault fractured zone (4), the main tunnel (1) is higher than the horizontal guide (2), the main tunnel (1) and the horizontal guide (2) have a descending slope along the A direction, a transverse tunnel (9) is arranged at the tunnel exit section, which runs through the main tunnel (1) to the horizontal guide (2), the water in the excavated section of the tunnel has flooded to the wellhead of the inclined shaft (5), and the invention is characterized in that: A first water retaining wall (6) is arranged at a position close to the exit section of the flat guide (2), and the lower part of the first water retaining wall (6) is not sealed to form a water outlet. The surrounding rock between the exit section of the flat guide (2) and the first water retaining wall (6) is reinforced by anchor rods. A second water retaining wall (7) is arranged on the side of the horizontal hole (9) in the flat guide (2) close to the exit, and a third water retaining wall (8) is arranged on the side of the horizontal hole (9) in the main hole (1) close to the exit. Drainage ditches are arranged on the left and right sides of the tunnel section between the first water retaining wall (6) and the second water retaining wall (7) and on the left and right sides of the horizontal hole between the second water retaining wall (7) and the third water retaining wall (8). A drainage channel connected to a natural river ditch is built at the exit of the horizontal hole (9). A drainage hole penetrating the exit section and the excavated section is drilled on the section to be excavated of the flat guide (2). The drainage hole is drilled by a horizontal directional drilling rig from the exit flat guide heading to the long-mileage flat guide heading direction.

2. The drainage structure for a long-distance tunnel in a deep-buried water-rich fractured zone according to claim 1 is characterized in that: At least two drainage holes are drilled from top to bottom along the height direction of the flat guide face.

3. The drainage structure for a long-distance tunnel in a deep-buried water-rich fractured zone according to claim 1 is characterized in that: The diameter of the drain hole is 250 mm.

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