Multifunctional tunnel construction auxiliary facility and design method thereof

Abstract

The invention discloses a multifunctional tunnel construction auxiliary facility and a design method thereof, and relates to the technical field of tunnel and underground engineering construction, and the multifunctional tunnel construction auxiliary facility is a sinking space arranged on tunnel inverted arch filling concrete; the sinking space extends to the outside of the tunnel from the vicinity of the tunnel face, and the top is sealed by a prefabricated cover plate; an escape pipeline is arranged at the end, close to the tunnel face, of the sinking space. The auxiliary facility comprehensively considers multiple functions of assisting personnel escape, assisting construction ventilation, assisting construction reverse slope drainage and the like, so that the same facility has different functions, the influence of various traditional pipelines on construction is greatly reduced, the requirement for tunnel construction space is reduced, and the construction efficiency is improved. And a ventilating pipeline and a reverse slope drainage water-collecting well which are restricted by the construction environment are also optimized. On the premise of guaranteeing the construction safety, the purposes of accelerating the construction progress, improving the ventilation efficiency and reducing the energy consumption are achieved, permanent and temporary combination can be achieved, and the project investment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel and underground engineering construction, and in particular to a multifunctional tunnel construction auxiliary facility and a design method thereof. Background Art

[0002] For tunnel construction, there are often many uncertain factors that affect construction safety due to its small working space, poor construction environment, and great geological influence. Before construction, not only should corresponding work be done from the perspective of preventing accidents, but also sufficient safety measures should be set up to support escape and rescue after emergencies.

[0003] From the perspective of structural safety, landslides are a common safety accident in tunnel construction, among which "closed-door" landslides are the most typical. At present, the industry mainly responds to landslides and other emergencies by setting up circular escape pipes made of steel or other composite materials that are resistant to rockfall impact near the face. Many studies have also proposed setting up emergency shelters near the face, and using escape pipes connected to them to achieve escape and rescue of personnel after accidents. The setting of the escape pipe needs to extend from the vicinity of the face to the section where the second lining structure is completed. Combined with the spacing requirements between each process, it is often necessary to set more than 100 meters, or even up to 150 meters. As the face continues to advance, the escape pipe needs to be dismantled, moved forward and reinstalled.

[0004] From the perspective of the breathing needs of construction workers, the tunnel needs to ensure that each person is supplied with 3m of fresh air per minute when there are people working. 3 As mentioned above, currently existing construction ventilation mostly adopts the pressure-in formula. The air duct is a hose, hung on the side wall of the tunnel, and the air duct is usually bent at the intersection with various work trolleys in the tunnel. Sharp parts such as steel bars and operating machinery in the tunnel will inevitably cause certain damage to the air duct. Bending of the air duct will increase the local resistance of the air supply of the air duct, causing power loss; and damage to the air duct (such as tearing, holes, etc.) will increase the air leakage rate of the air duct, resulting in insufficient actual air supply at the face.

[0005] For tunnels with downhill excavation direction, groundwater will accumulate near the face due to the existence of the tunnel longitudinal slope. If it is not discharged in time, the groundwater will soak the base surrounding rock for a long time, which will not only deteriorate the construction environment, but also reduce the bearing capacity of the base surrounding rock. Therefore, reverse slope drainage is particularly important during construction. At present, reverse slope drainage on site mostly adopts excavation of water collection wells or placement of water collection tanks on the side walls of the tunnel, and uses water pumps to pump out groundwater in stages. Excavation of water collection pits will occupy the construction space of the lining structure, causing unreasonable local stress on the structure and even affecting the safety of the structure; placing water collection tanks on the side walls of the tunnel will occupy the construction space in the tunnel, and the water collection tanks are often much higher than the tunnel pavement, which also requires a higher head of the water pump. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a multifunctional tunnel construction auxiliary facility and a design method thereof. Based on its special setting position, material properties and structural type, it can assist the escape of personnel in emergency situations during tunnel construction, can be used as a ventilation or exhaust duct for tunnel construction, and can also provide space for reverse slope drainage during tunnel construction; the multifunctional tunnel construction auxiliary facility integrates three functions in the invert filling layer, reduces the demand for construction space, reduces interference with construction, thereby improving construction efficiency and saving engineering construction investment.

[0007] The technical solution adopted by the present invention is:

[0008] A multifunctional tunnel construction auxiliary facility, which is a sunken space arranged on the tunnel invert filled with concrete; the sunken space is located on one side of the center line of the tunnel cross section, and extends from the vicinity of the tunnel face to the outside of the tunnel, the top of the sunken space is closed by a prefabricated cover plate, and the top surface of the prefabricated cover plate is flush with the top surface of the tunnel invert filled with concrete; an escape pipe is arranged at the end of the sunken space close to the tunnel face through an escape pipe foundation, one end of the escape pipe extends into the sunken space, and the other end extends to the tunnel face.

[0009] Furthermore, the cross-section of the sinking space is rectangular, and the cross-section of the escape duct is circular.

[0010] Furthermore, a fan is provided at one end of the sunken space extending to the outside of the tunnel, and the fan is located at the tunnel entrance; when the fan supplies air in a forward direction, the fresh air outside the tunnel is pressurized by the fan and then sent to the vicinity of the heading along the sunken space and the escape duct; when the fan provides reverse exhaust power, the dirty gas in the tunnel is discharged outside the tunnel along the escape duct and the sunken space.

[0011] Furthermore, an end seal for sealing the outer edge of the escape pipe is provided at the end of the sinking space.

[0012] When the tunnel excavation direction is downhill, the longitudinal slope of the sunken space is consistent with the longitudinal slope of the tunnel; a number of collection wells are arranged at a certain interval at the bottom of the sunken space, each collection well is equipped with a water pump, the water pump is connected to a drainage pipe, and the drainage pipe extends to the next collection well.

[0013] A design method for a multifunctional tunnel construction auxiliary facility, the design method is for an escape function tunnel construction auxiliary facility; the cross section of the sunken space is larger than the cross section of the escape pipe; the height and width of the cross section of the sunken space are expressed by the following formula:

[0014]

[0015] Wherein, b is the clear width of the cross section of the sinking space, in m; h is the clear height of the cross section of the sinking space, in m; d is the inner diameter of the circular escape duct, in m; t is the wall thickness of the circular escape duct, in m;

[0016] If the escape pipe uses a metal round pipe with an inner diameter of 0.95m and a wall thickness of 0.01m, the height and width of the sinking space section must be greater than 0.97m.

[0017] A design method for a multifunctional tunnel construction auxiliary facility, the design method is for a tunnel construction auxiliary facility with ventilation function; construction ventilation needs to provide sufficient fresh air for the workers at the face, and at the same time be able to discharge carbon dioxide generated by breathing in the tunnel and dust generated by construction;

[0018] When the sunken space and escape duct assist in construction ventilation, the cross-sectional dimensions of the sunken space need to satisfy the following formula:

[0019]

[0020] Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, the unit is m / s; b is the cross-sectional clearance width of the sunken space, the unit is m; h is the cross-sectional clearance height of the sunken space, the unit is m.

[0021] A design method for a multifunctional tunnel construction auxiliary facility, the design method is a drainage function tunnel construction auxiliary facility; during the construction period, reverse slope drainage needs to pump the water gushing near the heading face to the outside of the tunnel through a water collection well, a water pump and a drainage pipe in a relay formula; the volume of each water collection well needs to be greater than the water gushing of the tunnel within the distance between the water collection well and the previous water collection well;

[0022] The dimensions of the sump are given by:

[0023]

[0024] Where V j is the volume of the water collection well, in m3; b is the cross-sectional clearance width of the sinking space, in m; h j is the depth of the water collection well, in m; l j is the longitudinal length of the water collection well, in meters; i is the longitudinal slope of the tunnel; Q w is the predicted water inflow for the entire tunnel length, in m3 / s; L 1 is the distance between the water collection wells, in meters; L is the total length of the tunnel, in meters; k is the richness coefficient, which is generally greater than 1.

[0025] A design method for a multifunctional tunnel construction auxiliary facility, the design method is for a multifunctional tunnel construction auxiliary facility; if the multifunctional tunnel construction auxiliary facility is required to have three purposes of escape, ventilation, and drainage, the cross-sectional dimensions of the sinking space should satisfy the following formula:

[0026]

[0027] Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, in m / s; d is the inner diameter of the circular escape duct, in m; t is the wall thickness of the circular escape duct, in m; b is the cross-sectional clearance width of the sinking space, in m; h is the cross-sectional clearance height of the sinking space, in m.

[0028] The beneficial effects of the present invention are:

[0029] (1) The multifunctional tunnel construction auxiliary facility has a simple design and is easy to construct. It integrates multiple functions and can simultaneously realize the functions of assisting personnel escape, assisting construction ventilation, and assisting construction reverse slope drainage.

[0030] (2) The multifunctional tunnel construction auxiliary facility can be used in combination with the escape pipe, which can greatly reduce the length of the escape pipe and shorten the time for dismantling and reassembling the escape pipe, thereby ensuring safety and speeding up the construction progress.

[0031] (3) The auxiliary facility is used to replace the traditional ventilation duct. The facility is located in the back arch filling layer, which reduces the demand for tunnel construction sections. The facility is arranged at a fixed position along the longitudinal direction of the tunnel, with a smooth transition, avoiding problems such as duct bending caused by avoiding construction trolleys. The facility space is relatively closed, which reduces the air leakage rate of the duct and improves the construction ventilation efficiency.

[0032] (4) This facility is used for reverse slope drainage during construction. The water collection well does not occupy construction space and can also be used as a temporary water storage tank for tunnel water inrush. After operation, the facility can be used for drainage. At the same time, the water collection well can be used as a sand settling tank and inspection well for the ditch, taking into account both the construction period and the operation period, greatly saving project investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the layout of the multifunctional tunnel construction auxiliary facilities of the present invention in the tunnel;

[0034] Figure 2 A longitudinal section diagram of the construction auxiliary facility of the present invention for assisting construction workers to escape on stairs in an emergency;

[0035] Figure 3A longitudinal section diagram of the construction auxiliary facility of the present invention assisting construction workers to escape from stairs in an emergency;

[0036] Figure 4 This is a cross-sectional layout diagram of the multifunctional construction auxiliary facility of the present invention;

[0037] Figure 5 This is a cross-sectional layout diagram of the construction auxiliary facilities of the present invention when assisting in the construction of reverse slope drainage;

[0038] Figure 1 —5, 1—sunken space, 2—tunnel invert filled with concrete, 3—precast cover plate, 4—end seal, 5—escape pipe, 6—cover plate, 7—water pump, 8—drain pipe, 9—escape pipe foundation, 10—upper step face, 11—lower step face, 12—water collection well. DETAILED DESCRIPTION

[0039] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] For ease of description, spatially relative terms such as "upper," "lower," "left," and "right" may be used herein to describe the relationship of one element or feature shown in a figure to another element or feature. It should be understood that, in addition to the orientation shown in the processing figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, elements described as being "below" other elements or features will be defined as being "above" the other elements or features. Therefore, the exemplary term "below" can include both upper and lower orientations. The device can be positioned in other ways, and the spatially relative descriptions used herein can be interpreted accordingly.

[0041] Example 1

[0042] In view of the escape problem in tunnel construction, this embodiment proposes a multifunctional tunnel construction auxiliary facility. Figure 1 As shown, the multifunctional tunnel construction auxiliary facility is a sunken space 1 arranged on the tunnel invert filled with concrete 2, and the sunken space 1 is located on one side of the center line of the tunnel section; Figure 2 and Figure 3As shown, the sinking space 1 extends from the vicinity of the upper step face 10 or the vicinity of the lower step face 11 to the outside of the tunnel, and the top of the sinking space 1 is closed by a prefabricated cover plate 3, and the top surface of the prefabricated cover plate 3 is flush with the top surface of the tunnel invert filling concrete 2; an escape pipe 5 is arranged at the end of the sinking space 1 close to the face through an escape pipe foundation 9, and one end of the escape pipe 5 extends into the sinking space 1, and the other end extends to the upper step face 10 or the lower step face 11. The tunneling direction is shown by the arrow in the figure.

[0043] like Figure 2 and Figure 3 As shown, the sinking space 1 is flush with the end of the tunnel invert concrete 2 near the face, and the other end leads to the outside of the tunnel. The end of the escape pipe 5 near the face overlaps the sinking space 1. When an emergency such as a landslide occurs near the tunnel face, as shown by the arrow in the figure, the construction workers can escape into the sinking space 1 through the escape pipe 5, and uncover the prefabricated cover plate 3 at a safe position to escape. Using this multifunctional tunnel construction auxiliary facility to assist escape can reduce the scale of the escape pipe 5, make it more convenient to install the escape pipe 5 during construction, and facilitate the escape pipe 5 to move forward with the excavation of the face.

[0044] Further, as a preferred technical solution of this embodiment, Figure 4 As shown, the cross section of the sunken space 1 in this embodiment is rectangular, and the cross section of the escape pipe 5 is circular. The sunken space 1 is used in combination with the escape pipe 5 to greatly reduce the length of the escape pipe 5, shorten the time for dismantling and reassembling the escape pipe 5, ensure safety and speed up the construction progress.

[0045] Example 2

[0046] Based on the multifunctional tunnel construction auxiliary facilities provided in Example 1, in this embodiment, a fan is provided at one end of the sunken space 1 extending to the outside of the tunnel. The fan is located at the tunnel entrance, and the auxiliary construction ventilation function is realized by the fan in conjunction with the sunken space 1 and the escape duct 5.

[0047] Specifically, Figure 2 and Figure 3As shown, the starting point of the multifunctional construction auxiliary facility is located at the tunnel entrance, and a fan is installed at one end of the sunken space 1 extending to the outside of the tunnel, and its end point is located at the end of the tunnel invert. When used as a construction ventilation supply duct, the fresh air outside the tunnel is pressurized by the fan and then transported to the vicinity of the tunnel face along the sunken space 1 and the escape duct 5; when used as a construction ventilation exhaust duct, the fan provides reverse extraction power, and the dirty gas in the tunnel is discharged out of the tunnel along the escape duct 5 and the sunken space 1. Compared with the traditional separately set supply and exhaust ducts, the multifunctional construction auxiliary facility does not have bends, breakages, etc., avoids the increase of local ventilation resistance due to bends, cross-section changes, etc., and also solves the problem of increased air leakage rate due to damage of the soft air duct.

[0048] It should be noted that when the multifunctional construction auxiliary facility is used as a construction escape duct 5 and a ventilation duct, Figure 2 and Figure 3 As shown, an end seal 4 for sealing the outer edge of the escape duct 5 needs to be provided at the end of the sinking space 1, and the end seal 4 is sealed with an airtight soft material, such as a foam board or other materials, to avoid loss of air volume; in addition, it is necessary to ensure that sealing measures are adopted to seal the prefabricated cover plates 3 and between the prefabricated cover plates 3 and the top of the sinking space 1 to avoid loss of air volume.

[0049] Example 3

[0050] Based on the multifunctional tunnel construction auxiliary facilities provided in Example 1, such as Figure 4 and Figure 5 As shown, in this embodiment, the longitudinal slope of the multifunctional construction auxiliary facility is consistent with the longitudinal slope of the tunnel. When the tunnel excavation direction is downhill, a water collection well 12 is set at a certain interval at the bottom of the sinking space 1. The groundwater near the face is pumped to the water collection well 12 by the water pump 7, and then the water in the first water collection well 12 is pumped to the next water collection well 12 by the water pump 7, and then the water in the first water collection well 12 is pumped to the next water collection well 12, and then the water is relayed in sequence until the groundwater is discharged out of the tunnel. The difference from the conventional practice is that the multifunctional construction auxiliary facility is suitable for reverse slope drainage, does not affect the construction space of the tunnel, and does not affect the main structure of the tunnel. At the same time, the water collection well 12 can also be used as a sand settling tank for the drainage ditch during the operation of the tunnel, which is convenient for the inspection and maintenance of the ditch.

[0051] It should be noted that in order to avoid local resistance caused by sudden expansion and contraction of the water collection well 12 during ventilation, it is necessary to install a cover plate 6 above the water collection well 12 to ensure the consistency of the cross section. The cover plate 6 can be made of materials with high rigidity and strength such as steel and wood to minimize the thickness of the cover plate 6. After the tunnel construction is completed and enters the operation period, the cover plate 6 of the water collection well 12 is removed, and the water collection well 12 is used as a sand settling tank for the ditch.

[0052] Example 4

[0053] Based on the multifunctional tunnel construction auxiliary facilities provided in Example 1, Example 2, and Example 3, this embodiment provides a design method for a multifunctional tunnel construction auxiliary facility.

[0054] Specifically, when the multifunctional tunnel construction auxiliary facility is only used to assist construction escape:

[0055] like Figure 1 and Figure 4 As shown, in order to achieve the overlap between the escape pipe 5 and the sinking space 1, the cross section of the sinking space 1 needs to be larger than the cross section of the escape pipe 5 to enable the passage of personnel in an emergency. The height and width of the cross section of the sinking space 1 can be expressed by the following formula:

[0056]

[0057] In the formula, b is the cross-sectional clearance width of the sinking space, in m; h is the cross-sectional clearance height of the sinking space, in m; d is the inner diameter of the circular escape duct 5, in m; t is the wall thickness of the circular escape duct 5, in m.

[0058] The tunnel construction escape pipe 5 usually adopts a metal round pipe with an inner diameter of 0.95m and a wall thickness of 0.01m. Therefore, when this facility assists personnel to escape, the height and width of its cross section must be greater than 0.97m.

[0059] When the multifunctional tunnel construction auxiliary facility is used to assist construction ventilation:

[0060] Construction ventilation needs to provide sufficient fresh air for the workers on the face of the tunnel to breathe, while also being able to expel the carbon dioxide produced by breathing in the tunnel and the dust generated by construction.

[0061] When the sunken space 1 and the escape duct 5 assist in construction ventilation, the cross-sectional dimensions of the sunken space 1 need to satisfy the following formula:

[0062]

[0063] Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, the unit is m / s; b is the cross-sectional clearance width of the sunken space, the unit is m; h is the cross-sectional clearance height of the sunken space, the unit is m.

[0064] When the multifunctional tunnel construction auxiliary facility is used to assist in reverse slope drainage:

[0065] During the construction period, reverse slope drainage needs to pump out the water gushing near the face through the water collection well 12, water pump 7 and drainage pipe 8 in a relay formula to the outside of the tunnel. To meet the demand for pumping groundwater, the volume of each water collection well 12 needs to be greater than the water gushing of the tunnel within the distance between the water collection well 12 and the previous water collection well 12; to prevent the water in the water collection well 12 from overflowing, a certain amount of surplus should be considered.

[0066] like Figure 4 and Figure 5 As shown, the size of the water collection well 12 can be expressed by the following formula:

[0067]

[0068] Where: V j is the volume of the water collection well 12, in m3; b is the cross-sectional clearance width of the sinking space, in m; h j is the depth of the water collection well 12, in m; l j is the longitudinal length of the water collection well 12, in meters; i is the longitudinal slope of the tunnel; Q w is the predicted water inflow for the entire tunnel length, in m3 / s; L 1 is the distance between the water collection wells 12, in meters; L is the total length of the tunnel, in meters; k is the richness coefficient, which is generally greater than 1.

[0069] When the multifunctional tunnel construction auxiliary facility has three functions, namely, auxiliary construction escape, auxiliary construction ventilation, and auxiliary construction reverse slope drainage, its cross-sectional dimensions should meet the requirements of the public

[0070] Formula 1 and Formula 2, namely the following formula:

[0071]

[0072] Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, in m / s; d is the inner diameter of the circular escape duct 5, in m; t is the wall thickness of the circular escape duct 5, in m; b is the cross-sectional clearance width of the sinking space, in m; h is the cross-sectional clearance height of the sinking space, in m.

[0073] In summary, the multifunctional tunnel construction auxiliary facility has a simple design, convenient construction, and integrates multiple functions. It can simultaneously realize the functions of assisting personnel escape, assisting construction ventilation, and assisting construction reverse slope drainage. The multifunctional tunnel construction auxiliary facility can be used in combination with the multifunctional tunnel construction auxiliary facility through the escape pipe 5, which can greatly reduce the length of the escape pipe 5, shorten the time for dismantling and reassembling the escape pipe 5, and speed up the construction progress while ensuring safety. The auxiliary facility is used to replace the traditional ventilation pipe. The facility is located in the invert filling layer, which reduces the demand for the tunnel construction section; the facility is arranged at a fixed position along the longitudinal direction of the tunnel, and the transition is smooth, avoiding problems such as the bending of the air duct caused by avoiding the construction trolley; the space of the facility is relatively closed, which reduces the air leakage rate of the air duct and improves the construction ventilation efficiency. This facility is used for reverse slope drainage construction. The water collection well 12 does not occupy the construction space, and can also be used as a temporary water storage tank for tunnel water gushing. After operation, the facility can be used for drainage. At the same time, the water collection well 12 can be used as a sand settling tank and inspection well for the ditch, which comprehensively takes into account the construction period and the operation period, and greatly saves the project investment.

[0074] 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 multifunctional tunnel construction auxiliary facility, characterized in that: The multifunctional tunnel construction auxiliary facility is a sunken space arranged on the concrete filled with the tunnel invert; the sunken space is located on one side of the center line of the tunnel section, and extends from the vicinity of the tunnel face to the outside of the tunnel, and the top of the sunken space is closed by a prefabricated cover plate, and the top surface of the prefabricated cover plate is flush with the top surface of the concrete filled with the tunnel invert; an escape pipe is arranged at the end of the sunken space close to the tunnel face through an escape pipe foundation, and one end of the escape pipe extends into the sunken space, and the other end extends to the tunnel face.

2. The multifunctional tunnel construction auxiliary facility according to claim 1 is characterized in that: The cross section of the sinking space is rectangular, and the cross section of the escape duct is circular.

3. The multifunctional tunnel construction auxiliary facility according to claim 1 is characterized in that: A fan is provided at one end of the sunken space extending to the outside of the tunnel, and the fan is located at the tunnel entrance; when the fan supplies air in a forward direction, the fresh air outside the tunnel is pressurized by the fan and then sent to the vicinity of the heading along the sunken space and the escape duct; when the fan provides reverse exhaust power, the dirty gas in the tunnel is discharged outside the tunnel along the escape duct and the sunken space.

4. The multifunctional tunnel construction auxiliary facility according to claim 3 is characterized in that: An end seal for sealing the outer edge of the escape pipe is provided at the end of the sinking space.

5. The multifunctional tunnel construction auxiliary facility according to claim 1 is characterized in that: When the tunnel excavation direction is downhill, the longitudinal slope of the sunken space is consistent with the longitudinal slope of the tunnel; a number of collection wells are arranged at a certain interval at the bottom of the sunken space, each collection well is equipped with a water pump, the water pump is connected to a drainage pipe, and the drainage pipe extends to the next collection well.

6. A design method for a multifunctional tunnel construction auxiliary facility, the design method being directed to the multifunctional tunnel construction auxiliary facility according to any one of claims 1 or 2, characterized in that: The cross section of the sinking space is larger than the cross section of the escape pipe; the height and width of the cross section of the sinking space are expressed by the following formula: Wherein, b is the clear width of the cross section of the sinking space, in m; h is the clear height of the cross section of the sinking space, in m; d is the inner diameter of the circular escape duct, in m; t is the wall thickness of the circular escape duct, in m; If the escape pipe uses a metal round pipe with an inner diameter of 0.95m and a wall thickness of 0.01m, the height and width of the sinking space section must be greater than 0.97m.

7. A design method for a multifunctional tunnel construction auxiliary facility, the design method is directed to the multifunctional tunnel construction auxiliary facility according to any one of claims 3 or 4, characterized in that: Construction ventilation needs to provide sufficient fresh air for the workers on the face, and at the same time, it should be able to discharge the carbon dioxide produced by breathing in the tunnel and the dust produced by construction; When the sunken space and escape duct assist in construction ventilation, the cross-sectional dimensions of the sunken space need to satisfy the following formula: Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, the unit is m / s; b is the cross-sectional clearance width of the sunken space, the unit is m; h is the cross-sectional clearance height of the sunken space, the unit is m.

8. A design method for a multifunctional tunnel construction auxiliary facility, the design method being directed to the multifunctional tunnel construction auxiliary facility according to claim 5, characterized in that: During construction, reverse slope drainage requires that the water inflow near the face be pumped out of the tunnel through a water collection well, a water pump and a drainage pipe using a relay method; the volume of each water collection well needs to be greater than the water inflow of the tunnel within the distance between the water collection well and the previous water collection well; The dimensions of the sump are given by: Where V j is the volume of the water collection well, in m3; b is the cross-sectional clearance width of the sinking space, in m; h j is the depth of the water collection well, in m; l j is the longitudinal length of the water collection well, in m; i is the longitudinal slope of the tunnel; Q w is the predicted water inflow of the whole tunnel length, in m3 / s; L1 is the distance between the water collection wells, in m; L is the total length of the tunnel, in meters; k is the richness coefficient, which is generally greater than 1.

9. A design method for a multifunctional tunnel construction auxiliary facility, the design method being directed to the multifunctional tunnel construction auxiliary facility according to any one of claims 1 to 5, characterized in that: If the multifunctional tunnel construction auxiliary facility is required to have three purposes: escape, ventilation, and drainage, the cross-sectional dimensions of the sinking space should satisfy the following formula: Where Q is the required air volume for tunnel construction ventilation, in m 3 / s; v is the wind speed of the ventilation duct, in m / s; d is the inner diameter of the circular escape duct, in m; t is the wall thickness of the circular escape duct, in m; b is the cross-sectional clearance width of the sinking space, in m; h is the cross-sectional clearance height of the sinking space, in m.

Images