A tunnel bottom deformation monitoring device

Abstract

The present invention provides a tunnel bottom deformation monitoring device, which includes a monitoring horizontal plate, a measuring point pile, a measuring point pile hook, a lap sleeve, a protective sleeve, a measuring rod and a monitoring pile measuring point. The monitoring horizontal plate is arranged horizontally, the measuring point pile hook is arranged below the monitoring horizontal plate, the lap sleeve is arranged above the monitoring horizontal plate, the measuring point pile and the monitoring horizontal plate are arranged vertically, the upper part of the measuring point pile is located in the lap sleeve, the lower part of the measuring point pile passes through the monitoring horizontal plate and is connected to the measuring point pile hook, the protective sleeve is coaxially connected to the lap sleeve, the measuring rod is located in the protective sleeve, and the lower part of the measuring rod is connected to the measuring point pile, the measuring rod and the measuring point pile are arranged coaxially, the monitoring pile measuring point is arranged at the upper part of the measuring rod and protrudes from the protective sleeve, and the measuring point pile hook can drive the measuring point pile, the measuring rod and the monitoring pile measuring point to move together. The present invention can be deeply buried in the surrounding rock at the bottom of the tunnel, and is used for deformation monitoring of the deformation deep layer, and the monitoring data is more reliable and effective.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel deformation monitoring, and in particular to a tunnel bottom deformation monitoring device. Background Art

[0002] On-site monitoring and measurement during tunnel construction is an important part of tunnel construction management. It can not only guide construction, predict dangerous situations and ensure safety, but also obtain dynamic information (data) of surrounding rock through on-site monitoring, provide information basis for correcting and determining initial support parameters and concrete lining support time, and provide reliable and sufficient data for improving design and guiding construction.

[0003] At present, for complex tunnel engineering sections with poor geological conditions, monitoring and measurement are required to observe the surrounding rock and support status, arch crown sinking, peripheral convergence, and invert arch floating (such as Fig.12 The monitoring object of the floating arch is the filling surface after the tunnel bottom is constructed and the upper arch and filling concrete are poured. The purpose is to analyze the deformation of the lower tunnel bottom by monitoring the changes in the filling surface elevation. High-precision electronic levels and total stations are usually used for elevation measurement.

[0004] As we all know, tunnel deformation is fundamentally caused by the release of surrounding rock stress. The floating of the tunnel invert is only the final appearance. The initial deformation should start from the deformation of the lower part of the tunnel bottom. The development and intensification of deformation will inevitably lead to the failure of the primary support system of the tunnel bottom, and finally transmit to the invert and the invert filling. Therefore, the traditional invert floating monitoring project is basically a "phenomenon after deformation" observation, which cannot achieve the "deformation depth" monitoring requirements for the early, middle and late stages of the primary support of the tunnel bottom, and it is also impossible to effectively monitor the tunnel bottom of complex geological tunnels, especially the tunnel bottom of soft rock with large deformation, resulting in the inability to predict and analyze the timing and stability effect of the later invert and filling construction.

[0005] At present, another solution for monitoring the buoyancy of inverted arches at home and abroad is to use a micro-pressure difference static level settlement monitoring system. The system consists of a data collector, a reference liquid tank, a settlement meter, and a connecting water pipe. The connecting water pipe and the settlement meter are buried along the line to be monitored, and the liquid level in the reference liquid tank is kept stable during the monitoring process. If the monitoring line settles, the connecting water pipe will be displaced, and the pressure of the settlement meter will change. By comparing the data collected twice before and after, the vertical displacement of each point on the line can be calculated. The micro-pressure difference static leveling settlement monitoring system has high monitoring accuracy and can achieve a certain degree of informatization, but it is still an observation of the "appearance after deformation" of the invert filling surface; through research and engineering case analysis, the system is currently difficult to apply to the lower part of the tunnel bottom, and through multiple on-site equipment installation tests, the equipment has extremely poor resistance to the interference of initial support deformation, and after being pre-buried at the bottom of the tunnel, it is affected by the concrete construction, and its settlement meter survival rate is extremely low. The height difference limit of the connected water tank cannot meet the "deformation range" of large deformation, and other shortcomings caused the system to fail in the tunnel bottom burial and subsequent monitoring tests.

[0006] For the current complex tunnel projects, there is no effective successful experience in the industry to refer to for the monitoring of tunnel bottom deformation during the construction phase. Moreover, the research on tunnel bottom monitoring itself is a reform of the monitoring principle of the traditional invert floating monitoring project, which is an observation of the "appearance after deformation". How to truly and effectively implement the "deformation depth" monitoring of the early, mid-term and late stages of the initial support of the tunnel bottom, and scientifically and reasonably guide the timing and stability analysis of the later invert and filling construction through monitoring data, will definitely be a difficult problem in the field of tunnel deformation monitoring technology and needs to be solved urgently. Summary of the invention

[0007] The purpose of the present invention is to provide a tunnel bottom deformation monitoring device which can be deeply buried in the surrounding rock of the tunnel bottom and perform deformation monitoring on the deep layer of the tunnel bottom.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a tunnel bottom deformation monitoring device, including a monitoring horizontal plate, a measuring point pile, a measuring point pile hook, an overlapping sleeve, a protective sleeve, a measuring rod and a monitoring pile measuring point. The monitoring horizontal plate is arranged horizontally, the measuring point pile hook is arranged below the monitoring horizontal plate, the overlapping sleeve is arranged above the monitoring horizontal plate, the measuring point pile and the monitoring horizontal plate are arranged vertically, the upper part of the measuring point pile is arranged in the overlapping sleeve, the lower part of the measuring point pile passes through the monitoring horizontal plate and is connected to the measuring point pile hook, the protective sleeve is coaxially connected to the overlapping sleeve, the measuring rod is located in the protective sleeve, and the lower part of the measuring rod is connected to the measuring point pile, the measuring rod and the measuring point pile are arranged coaxially, the monitoring pile measuring point is arranged at the upper part of the measuring rod and protrudes from the protective sleeve, and the measuring point pile hook can drive the measuring point pile, the measuring rod and the monitoring pile measuring point to move together.

[0009] It can be seen from the above scheme that the measuring point pile hook, measuring point pile, measuring rod and monitoring pile measuring point are arranged in sequence from bottom to top, and the measuring point pile hook can be buried in the monitoring pile at the bottom of the tunnel. If the bottom of the tunnel is deformed by floating, the measuring point pile hook will float up, thereby driving the measuring point pile, measuring rod and monitoring pile measuring point to float up together. The construction personnel can monitor the bottom of the tunnel by monitoring the position of the pile measuring point through the monitoring instrument above the invert filling. The monitoring device of the present invention is deeply buried in the surrounding rock of the tunnel and is installed synchronously during the initial support construction process of the tunnel bottom. It can monitor the deformation of the early, middle and late stages of the initial support of the tunnel, and the monitoring data is more reliable and effective.

[0010] A further solution is that a first fixing ring is provided in the middle of the measuring point pile, and the first fixing ring protrudes from the outer peripheral wall of the measuring point pile; a mounting hole is opened in the middle of the monitoring horizontal plate, and the measuring point pile and the mounting hole are clearance-matched, the outer diameter of the first fixing ring is larger than the diameter of the mounting hole, and the first fixing ring abuts against the top of the mounting hole.

[0011] It can be seen from the above scheme that by setting the mounting hole on the monitoring horizontal plate, the lower part of the measuring point pile is located in the mounting hole. If the bottom of the tunnel floats, the measuring point pile can move up relative to the monitoring horizontal plate. The setting of the mounting hole also facilitates the adjustment of the verticality of the measuring point pile during the installation process.

[0012] A further solution is that both ends of the measuring point pile are respectively connected to the measuring point pile hook and the measuring rod thread.

[0013] It can be seen from the above scheme that by setting up a threaded connection, the connection and installation of the three are facilitated, the installation efficiency is improved, and the connection firmness is ensured.

[0014] A further solution is that the lower part of the protective sleeve is sleeved on the outside of the lap sleeve, and the protective sleeve and the lap sleeve are sealed and connected; an annular flange and a first sealing ring are provided on the inner side of the lower part of the protective sleeve, and there is a preset distance between the annular flange and the surface of the measuring rod, and the first sealing ring is sealingly connected between the annular flange and the end of the lap sleeve.

[0015] It can be seen from the above scheme that by providing the annular flange and the first sealing ring, it is helpful to ensure the sealed connection between the protective sleeve and the lap sleeve, preventing the concrete from entering the lap sleeve from between the protective sleeve and the lap sleeve during the subsequent pouring of concrete, thereby affecting the free movement of the measuring point pile in the lap sleeve.

[0016] A further solution is that the measuring rod comprises at least two segmented measuring rods, and the two segmented measuring rods are detachably connected and coaxially arranged.

[0017] It can be seen from the above scheme that by providing at least two segmented measuring rods connected to form a measuring rod of a preset height, on the one hand, it is convenient for transporting and storing the measuring rods, and on the other hand, it is possible to connect a suitable number of segmented measuring rods according to different elevations.

[0018] A further solution is that the tunnel bottom deformation monitoring device also includes a measuring point installation sleeve and a protective cover. The measuring point installation sleeve is sealingly connected to the upper part of the protective sleeve. A accommodating cavity is opened in the measuring point installation sleeve. The accommodating cavity is connected to the interior of the protective sleeve. The monitoring pile measuring point is exposed in the accommodating cavity, and the protective cover is detachably covered on the accommodating cavity.

[0019] It can be seen from the above scheme that by setting the measuring point installation sleeve and the protective cover, it is beneficial to prevent the filling material from entering the protective sleeve when the invert is filled, thereby affecting the accuracy of the monitoring results, and plays a role in protecting the monitoring pile measuring point.

[0020] A further solution is that the protective cover includes a cover plate, a peripheral wall, an elastic hook and a sealing foam adhesive, the peripheral wall is located below the cover plate, the elastic hook is located outside the peripheral wall, the elastic hook can elastically move along the radial direction of the cover plate, and the sealing foam adhesive is located between the peripheral wall and the elastic hook. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of an embodiment of a tunnel bottom deformation monitoring device of the present invention.

[0022] Figure 2 yes Figure 1 Enlarged view of point A in the middle.

[0023] Figure 3 yes Figure 1 Enlarged view of point B in the middle.

[0024] Figure 4 It is an exploded view of the measuring rod in the embodiment of the tunnel bottom deformation monitoring device of the present invention.

[0025] Figure 5 It is a schematic diagram of monitoring piles in an embodiment of the construction method of the tunnel bottom deformation monitoring device of the present invention.

[0026] Figure 6 yes Figure 5 Enlarged view of point C in the middle.

[0027] Figure 7 It is a schematic diagram of applying initial support concrete for the tunnel bottom in an embodiment of the construction method of the tunnel bottom deformation monitoring device of the present invention.

[0028] Figure 8 yes Figure 7 Enlarged view of point D in the middle.

[0029] Fig. 9 It is a structural diagram of installing a protective sleeve and a measuring rod in an embodiment of the construction method of a tunnel bottom deformation monitoring device of the present invention.

[0030] Fig.10It is a structural diagram of constructing an invert and filling the invert in an embodiment of the construction method of the tunnel bottom deformation monitoring device of the present invention.

[0031] Fig.11 It is a structural diagram of a ballastless track in an embodiment of a construction method of a tunnel bottom deformation monitoring device of the present invention.

[0032] Fig.12 It is a schematic diagram of the stress effect on the surrounding rock at the bottom of the tunnel in the prior art.

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0034] Embodiment of tunnel bottom deformation monitoring device

[0035] See also Figures 1 to 3 The tunnel bottom deformation monitoring device provided in this embodiment includes a monitoring horizontal plate 1, a measuring point pile 2, a measuring point pile hook 3, a lap sleeve 4, a protective sleeve 5, a measuring rod 6, a monitoring pile measuring point 7, a measuring point installation sleeve 8 and a protective cover 9.

[0036] The monitoring horizontal plate 1 is set in a rectangular shape and arranged in the horizontal direction. A level bubble is provided on it to facilitate the leveling operation when the monitoring horizontal plate 1 is installed. Lower convex parts are provided around the bottom surface of the monitoring horizontal plate 1. The lower convex parts protrude downward from the bottom surface of the monitoring horizontal plate 1 and are used to be inserted into the concrete of the monitoring pile 20 to limit the movement of the monitoring horizontal plate 1 in the horizontal direction. A mounting hole 11 is opened in the middle of the monitoring horizontal plate 1, and the mounting hole 11 runs through the thickness direction of the monitoring horizontal plate 1.

[0037] The measuring point pile hook 3 is arranged below the middle of the monitoring horizontal plate 1 and at a preset distance from the monitoring horizontal plate 1. The free end and the connecting end of the measuring point pile hook 3 are arranged upward, and a first threaded connecting portion 31 is provided on the connecting end of the measuring point pile hook 3. The first threaded connecting portion 31 is located directly below the mounting hole 11.

[0038] The lap sleeve 4 is arranged above the monitoring horizontal plate 1. The lap sleeve 4 and the mounting hole 11 are coaxially arranged and interconnected. The inner diameter of the lap sleeve 4 is larger than the diameter of the mounting hole 11, so that an annular stopper is formed between the inner surface of the lap sleeve 4 and the mounting hole 11.

[0039] The measuring point pile 2 is arranged vertically with the monitoring horizontal plate 1, the upper part of the measuring point pile 2 is arranged in the overlapping sleeve 4, and the lower part of the measuring point pile 2 passes through the mounting hole 11 and is connected with the measuring point pile hook 3. Specifically, a first fixing ring 21 is arranged in the middle part of the measuring point pile 2, and the first fixing ring 21 protrudes from the outer peripheral wall of the measuring point pile 2 along the circumference of the measuring point pile 2, and the outer diameter of the first fixing ring 21 is larger than the diameter of the mounting hole 11 and smaller than the inner diameter of the overlapping sleeve 4. The measuring point pile 2 is clearance-matched with the mounting hole 11, and the first fixing ring 21 abuts on the top of the mounting hole 11, that is, the first fixing ring 21 abuts against the stopper, so that the measuring point pile 2 can move upward but cannot move downward; of course, due to the clearance-matched between the measuring point pile 2 and the mounting hole 11, under the deformation of the tunnel bottom, the measuring point pile 2 can be tilted at a small angle in the overlapping sleeve 4.

[0040] The upper and lower ends of the measuring point pile 2 are respectively threadedly connected with the measuring point pile hook 3 and the measuring rod 6. Specifically, the lower part of the measuring point pile 2 is provided with a second threaded connection part 22, and the second threaded connection part 22 is threadedly connected with the first threaded connection part 31. In this embodiment, the first threaded connection part 31 is a raised threaded column, and the second threaded connection part 22 is a threaded groove. The upper part of the measuring point pile 2 is provided with a third threaded connection part 23, and the third threaded connection part 23 protrudes upward from the lap sleeve 4, and the third threaded connection part 23 is coaxially arranged with the second threaded connection part 22. The lower part of the measuring rod 6 is provided with a fourth threaded connection part 65, and the fourth threaded connection part 65 is connected with the third threaded connection part 23. In this embodiment, the third threaded connection part 23 is a raised threaded column, and the fourth threaded connection part 65 is a threaded groove.

[0041] The protective sleeve 5 is coaxially connected to the overlapping sleeve 4, and the lower part of the protective sleeve 5 is sleeved on the outer side of the overlapping sleeve 4. An annular flange 51 and a first sealing ring 52 are provided on the inner side of the lower part of the protective sleeve 5. The annular flange 51 protrudes from the inner side of the protective sleeve 5 toward the center of the protective sleeve 5, and is used to connect with the upper end of the overlapping sleeve 4 to limit the protective sleeve 5 from moving downward relative to the overlapping sleeve 4. The first sealing ring 52 is sealed between the annular flange 51 and the upper end of the overlapping sleeve 4 to achieve a sealed connection between the protective sleeve 5 and the overlapping sleeve 4, to prevent the concrete from entering the overlapping sleeve 4 from between the protective sleeve 5 and the overlapping sleeve 4 when the tunnel invert concrete is constructed, and to avoid the concrete from limiting the free movement of the measuring point pile 2.

[0042] The measuring rod 6 is located in the protective sleeve 5. The measuring rod 6 is a solid steel rod. There is a preset distance between the surface of the measuring rod 6 and the annular flange 51, that is, the protective sleeve 5 is not in direct contact with the measuring rod 6. The measuring rod 6 is coaxially arranged with the measuring point pile 2. In the vertical direction, the top surface of the measuring rod 6 is flush with the top surface of the protective sleeve 5.

[0043] The measuring point installation sleeve 8 is sealed and connected to the upper part of the protective sleeve 5. Specifically, the measuring point installation sleeve 8 includes a lower connecting portion 81 and an upper connecting portion 82. The outer diameter of the lower connecting portion 81 is smaller than the outer diameter of the upper connecting portion 82, so that a step portion 83 is formed between the lower connecting portion 81 and the upper connecting portion 82, and the step portion 83 extends in the horizontal direction. The lower connecting portion 81 is inserted into the protective sleeve 5, and the step portion 83 abuts against the upper end of the protective sleeve 5. A second sealing ring 85 is provided between the step portion 83 and the upper end of the protective sleeve 5 to prevent the filler from entering the protective sleeve 5 when the inverted arch is filled. A receiving cavity 84 is formed on the inner side of the upper connecting portion 82, and the receiving cavity 84 is communicated with the inside of the protective sleeve 5.

[0044] The monitoring pile measuring point 7 is threadedly connected to the upper part of the measuring rod 6 and protrudes from the protective sleeve 5, that is, the monitoring pile measuring point 7 is exposed in the accommodating cavity 84, and the inner diameter of the accommodating cavity 84 is larger than the outer diameter of the monitoring pile measuring point 7, which is convenient for the subsequent monitoring instrument to monitor the spatial displacement data of the monitoring pile measuring point 7. The monitoring instrument can use a high-precision total station, and the spatial displacement data includes but is not limited to: height displacement, horizontal displacement, and verticality.

[0045] If the tunnel bottom is deformed and the measuring point pile hook 3 moves, when the measuring point pile hook 3 floats up, the measuring point pile hook 3 can drive the measuring point pile 2, the measuring rod 6 and the monitoring pile measuring point 7 to move synchronously. Therefore, the monitoring instrument can realize the deformation monitoring of the deep layer of the tunnel bottom by monitoring the spatial displacement data of the monitoring pile measuring point 7.

[0046] In order to prevent concrete or other debris from entering the measuring point installation sleeve 8 during the tunnel construction process, a protective cover 9 can be provided in the measuring point installation sleeve 8. The protective cover 9 is detachably covered on the accommodating cavity 84. The protective cover 9 includes a cover plate 91, a peripheral wall 92, a sealing foam glue 93 and at least two elastic hooks 94. The cover plate 91 is set to be circular in shape matching the accommodating cavity 84, and the outer diameter of the cover plate 91 is equal to or slightly larger than the outer diameter of the measuring point installation sleeve 8. The peripheral wall 92 is located below the cover plate 91. The two elastic hooks 94 are arranged relatively on the outside of the peripheral wall 92, and the elastic hooks 94 are in an inverted state, that is, the hook portion of the elastic hook 94 is arranged upward. The sealing foam glue 93 is filled between the peripheral wall 92 and the elastic hook 94. The sealing foam glue 93 has a certain elasticity, so that the elastic hook 94 can move elastically along the radial direction of the cover plate 91. When necessary, the peripheral wall 92 and the elastic hook 94 are embedded in the accommodating cavity 84, and the protective cover 9 is clamped in the measuring point installation sleeve 8 by the elasticity of the elastic hook 94. A lifting ring is provided on the top surface of the cover plate 91 to facilitate opening the cover plate 91 upwards.

[0047] exist Figure 4In the embodiment, the measuring rod 6 includes at least two segmented measuring rods 61. In this embodiment, two segmented measuring rods 61 are used as an example. The length of each segmented measuring rod 61 is 100 cm to 200 cm. The two segmented measuring rods 61 are coaxially arranged. The two segmented measuring rods 61 are detachably connected by threads. Specifically, a fifth threaded connection portion 62 is provided on the lower segmented measuring rod 61, and a sixth threaded connection portion 63 is provided on the upper segmented measuring rod 61. The fifth threaded connection portion 62 is threadedly connected with the sixth threaded connection portion 63. In this embodiment, the fifth threaded connection portion 62 is a raised threaded column, and the sixth threaded connection portion 63 is a threaded groove. A second fixing ring 64 is provided in the middle of each segmented measuring rod 61. The second fixing ring 64 is protrudingly arranged along the circumference of the segmented measuring rod 61. The outer diameter of the second fixing ring 64 is larger than the outer diameter of the segmented measuring rod 61, and the outer diameter of the second fixing ring 64 is smaller than the inner diameter of the protective sleeve 5, so that the second fixing ring 64 is at a preset distance from the inner wall of the protective sleeve 5.

[0048] When the measuring point pile 2 tilts at a small angle in the vertical direction, the segmented measuring rod 61 connected thereto also tilts. When the segmented measuring rod 61 tilts, the second fixing ring 64 can prevent the segmented measuring rod 61 from directly contacting the protective sleeve 5, thereby limiting the tilt angle of the segmented measuring rod 61.

[0049] Construction method embodiment of tunnel bottom deformation monitoring device

[0050] See also Figures 5 to 12 The construction method of the tunnel bottom deformation monitoring device of the above embodiment includes the following steps:

[0051] Step 1, in Figure 5 and Figure 6 In the process, after the initial support of the steel arch frame 10 at the bottom of the tunnel is completed, the monitoring piles 20 are positioned according to three horizontal measuring points and a monitoring section every 5m in the vertical direction. The middle monitoring pile 20 is located just on the center line of the bottom of the tunnel. Then the pile formwork is erected and the monitoring piles 20 are cast with C25 concrete.

[0052] When pouring the monitoring pile foundation 20, the monitoring horizontal plate 1, the measuring point pile 2, the overlapping sleeve 4 and the measuring point pile hook 3 are set. The monitoring horizontal plate 1 is horizontally set on the top of the monitoring pile foundation 20, and the upper surface of the monitoring horizontal plate 1 should be about 2 mm higher than the concrete surface. The measuring point pile hook 3 is buried in the monitoring pile foundation 20 and is located below the monitoring horizontal plate 1, and the connecting end of the measuring point pile hook 3 is just below the mounting hole 11 in the middle of the monitoring horizontal plate 1. The overlapping sleeve 4 is vertically set above the monitoring horizontal plate 1, and the inside of the overlapping sleeve 4 is connected to the mounting hole 11. The measuring point pile 2 is arranged vertically with the monitoring horizontal plate 1, the upper part of the measuring point pile 2 is located in the overlapping sleeve 4, the upper part of the overlapping sleeve 4 and the upper part of the measuring point pile 2 are higher than the steel arch 10, and the lower part of the measuring point pile 2 passes through the mounting hole 11 and is connected to the connecting end of the measuring point pile hook 3.

[0053] Step 2: Figure 7 and Figure 8 In the process, C25 concrete is used to cast the initial support 30 of the tunnel bottom, so that the monitoring horizontal plate 1 and the overlapping sleeve 4 are buried in the concrete of the initial support 30 of the tunnel bottom, and the upper part of the overlapping sleeve 4 and the upper part of the measuring point pile 2 are higher than the upper surface of the concrete of the initial support 30 of the tunnel bottom. Before pouring concrete, geotextile can be used to wrap the upper part of the overlapping sleeve 4 and the upper part of the measuring point pile 2 to prevent concrete from entering the overlapping sleeve 4 and directly contacting the measuring point pile 2. After the concrete pouring is completed, the geotextile should be removed and cleaned in time.

[0054] Step three, tying the invert arch reinforcement on the initial support 30 of the tunnel bottom and installing the invert arch formwork.

[0055] Step 4, see Fig. 9 Combined with Figure 1 , install the measuring rod 6, the protective sleeve 5, the measuring point installation sleeve 8, the monitoring pile measuring point 7 and the protective cover 9. The protective sleeve 5 is connected to the overlapping sleeve 4, the measuring rod 6 is connected to the measuring point pile 2, and the measuring rod 6 is located in the protective sleeve 5, the measuring point installation sleeve 8 is arranged on the upper part of the protective sleeve 5, the monitoring pile measuring point 7 is connected to the upper part of the measuring rod 6, and the monitoring pile measuring point 7 is exposed in the measuring point installation sleeve 8, and the protective cover 9 is covered on the measuring point installation sleeve 8. When the bottom of the tunnel is deformed, the measuring point pile hook 3 can drive the measuring point pile 2, the measuring rod 6 and the monitoring pile measuring point 7 to move synchronously. The protective sleeve 5 and the measuring rod 6 need to be controlled according to the elevation of the designed invert filling 50 surface, and it is necessary to ensure that the top surface elevation of the protective cover 9 is 2mm lower than the surface elevation of the invert filling 50.

[0056] Step 5, see Fig.10 , and combined with Figure 1 , cast the inverted arch 40 and the inverted arch filling 50, so that the protective sleeve 5 and the measuring point installation sleeve 8 are buried in the inverted arch 40 and the inverted arch filling 50, and ensure that the protective cover 9 can be removed from the measuring point installation sleeve 8. Before casting, the protective sleeve 5 needs to be reinforced and fixed with steel bars, etc., to ensure that during the casting of the inverted arch 40 and the inverted arch filling 50, the verticality of the protective sleeve 5 and the monitoring horizontal plate 1 meets the design requirements, that is, to ensure that the protective sleeve 5 is always in a vertical state.

[0057] After the concrete pouring of the inverted arch 40 and the inverted arch filling 50 is completed, the concrete slurry on the protective cover 9 should be cleaned in time, and prominent marks such as red paint should be made on the construction site.

[0058] After the invert filling 50 is poured, the initial value of the first monitoring can be collected. First, the protective cover 9 is opened and a monitoring instrument is installed at the monitoring pile measuring point 7. The spatial displacement data of the monitoring pile measuring point 7 is monitored to detect whether the deep layer of the tunnel bottom is deformed. The monitoring instrument can use a high-precision total station. The spatial displacement data includes but is not limited to: height displacement, horizontal displacement, and verticality. After that, each monitoring pile measuring point 7 can be monitored regularly. Of course, the present embodiment can also be used to monitor in the early and middle stages of the initial support, that is, the spatial displacement data of the measuring point pile 2 or the measuring rod 6 can be directly detected by the monitoring instrument, so as to realize the scientific and reasonable understanding of the construction timing and stability analysis of the later invert 40 and the invert filling 50 through the monitoring data.

[0059] It should be noted that the protective cover 9 should be put on in time after each monitoring to protect the measuring point.

[0060] Step 6, see Fig.11 Combined with Figure 1 , a ballastless track 60 is constructed on the invert filling 50. Since the ballastless track 60 is located in the middle of the invert filling 50 and is higher than the surface of the invert filling 50, in step 5, the protective casing 5 in the middle of the tunnel is directly replaced with a longer casing and a measuring rod 6 to reach the elevation of the ballastless track 60, or, before constructing the ballastless track 60, an extension casing 70 is overlapped on the protective casing 5 below the ballastless track 60, and the extension casing 70 is coaxially arranged and connected with the protective casing 5, the measuring point installation sleeve 8 and the protective cover 9 are both located at the top of the extension casing 70, the monitoring pile measuring point 7 is located in the measuring point installation sleeve 8, and the top surface of the protective cover 9 is slightly lower than the surface of the track bed 601 of the ballastless track 60.

[0061] The deformation monitoring work of the tunnel bottom should be carried out from the beginning of monitoring to the completion of the construction of the ballastless track 60, and the data of the entire monitoring period should be analyzed. When all the monitoring work is completed, if no further monitoring is needed, the protective casing 5 can be filled with self-compacting mortar. If long-term monitoring is still required after its operation, reinforcement and fixing measures of the protective cover 9 should be taken.

[0062] In summary, the monitoring piles of the present invention are deeply buried in the surrounding rock of the tunnel bottom, and then monitoring horizontal plates, measuring point piles and measuring point pile hooks are buried in the monitoring piles to ensure the stability of the measuring points; the present invention also extends the measuring points to the surface of the invert filling through measuring rods and monitoring pile measuring points as the initial support of the tunnel, the invert and the concrete construction of the invert filling, so as to facilitate the spatial displacement data monitoring of the monitoring pile measuring points; the present invention arranges a protective cover on the top of the monitoring pile measuring point, which has the functions of waterproof, dustproof and pressure-proof; the present invention can realize the early, middle and late deformation deep monitoring of the initial support of the tunnel bottom within the entire life cycle, and completely solves the disadvantage of "appearance after deformation" monitoring in the traditional invert floating monitoring, and the monitoring data is reliable and effective, and the on-site implementation effect is extremely significant.

[0063] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A tunnel bottom deformation monitoring device, characterized in that: It includes a monitoring horizontal plate, a measuring point pile, a measuring point pile hook, an overlapping sleeve, a protective sleeve, a measuring rod and a monitoring pile measuring point, wherein the monitoring horizontal plate is arranged horizontally, the measuring point pile hook is arranged below the monitoring horizontal plate, the overlapping sleeve is arranged above the monitoring horizontal plate, the measuring point pile and the monitoring horizontal plate are arranged vertically, the upper part of the measuring point pile is arranged in the overlapping sleeve, the lower part of the measuring point pile passes through the monitoring horizontal plate and is connected to the measuring point pile hook, the protective sleeve is coaxially connected to the overlapping sleeve, the measuring rod is located in the protective sleeve, and the lower part of the measuring rod is connected to the measuring point pile, the measuring rod and the measuring point pile are arranged coaxially, the monitoring pile measuring point is arranged at the upper part of the measuring rod and protrudes from the protective sleeve, and the measuring point pile hook can drive the measuring point pile, the measuring rod and the monitoring pile measuring point to move together; A first fixing ring is provided in the middle of the measuring point pile, and the first fixing ring protrudes from the outer peripheral wall of the measuring point pile; A mounting hole is provided in the middle of the monitoring horizontal plate, the measuring point pile is in clearance fit with the mounting hole, the outer diameter of the first fixing ring is larger than the diameter of the mounting hole, and the first fixing ring abuts against the top of the mounting hole; The measuring rod comprises at least two segmented measuring rods, and the two segmented measuring rods are detachably connected and coaxially arranged; The tunnel bottom deformation monitoring device also includes a measuring point installation sleeve and a protective cover. The measuring point installation sleeve is sealingly connected to the upper part of the protective sleeve. A accommodating cavity is opened in the measuring point installation sleeve. The accommodating cavity is connected to the interior of the protective sleeve. The monitoring pile measuring point is exposed in the accommodating cavity, and the protective cover is detachably covered on the accommodating cavity.

2. The tunnel bottom deformation monitoring device according to claim 1, characterized in that: The two ends of the measuring point pile are respectively connected with the measuring point pile hook and the measuring rod threadedly.

3. The tunnel bottom deformation monitoring device according to claim 1, characterized in that: The lower part of the protective sleeve is sleeved on the outer side of the overlapping sleeve, and the protective sleeve and the overlapping sleeve are sealed and connected; An annular flange and a first sealing ring are provided on the inner side of the lower part of the protective sleeve. There is a preset distance between the annular flange and the surface of the measuring rod. The first sealing ring is sealingly connected between the annular flange and the end of the lap sleeve.

4. The tunnel bottom deformation monitoring device according to claim 1, characterized in that: The protective cover includes a cover plate, a peripheral wall, an elastic hook and a sealing foam adhesive. The peripheral wall is located below the cover plate, the elastic hook is located on the outside of the peripheral wall, the elastic hook can elastically move along the radial direction of the cover plate, and the sealing foam adhesive is arranged between the peripheral wall and the elastic hook.

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