A construction technology for inverted excavation in the upward-sloping section of a tunnel

Abstract

The present invention discloses an inverted excavation construction technology for the uphill section of a tunnel. The excavation of the uphill section is constructed by the drill and blast method, and the construction is carried out successively from inside the station to the outside, and the multi-level bench method is used for cyclic construction; one scheme is to use the three-level bench method for excavation and support without an operation platform, and another scheme is to use the two-level bench method for excavation and support with an operation platform. By reducing the height of the upper bench and reserving the core soil, the present invention provides an operation platform for subsequent excavation and support construction, improves the construction safety quality and progress. In addition, through the support construction of the operation platform, the excavated rock slag is used for platform bedding and slope repair, which solves the problems of high traffic safety risks for personnel going up and down, difficult access for equipment, large difficulty in material transportation, and relatively high construction safety risks.

Description

Technical Field

[0001] The present invention relates to the technical field of the cut-and-cover construction of the climbing section of a tunnel. More specifically, the present invention relates to an inverted cut-and-cover construction process for the climbing section of a tunnel. Background Art

[0002] For the cut-and-cover construction of the 30° steep uphill climbing section of the auxiliary entrance of a shallow-buried extra-large cross-section subway station, due to the construction of the 30° steep slope climbing section, except for excavators, other equipment cannot enter the construction site, the operation of mechanical equipment is restricted, the slope is relatively large during the construction of the entrance climbing section, the traffic safety risk of personnel going up and down is high, it is difficult for equipment to enter and exit, the material transportation is difficult, and the construction safety risk is relatively high. Therefore, it is necessary to design a more suitable excavation method for the climbing section, combined with the excavation and support construction, to successfully complete the inverted cut-and-cover construction of the tunnel climbing section. Summary of the Invention

[0003] An object of the present invention is to provide an inverted cut-and-cover construction process for the climbing section of a tunnel, by reducing the height of the upper bench and reserving the core soil, providing an operation platform for subsequent excavation and support construction, improving the construction safety quality and progress. In addition, through the support construction of the working platform frame, the excavated rock slag is used for platform padding and slope repair, solving the problems of high traffic safety risk of personnel going up and down, difficult equipment entry and exit, difficult material transportation, and relatively high construction safety risk.

[0004] In order to achieve these and other advantages of the present invention, an inverted cut-and-cover construction process for the climbing section of a tunnel is provided. The climbing section is excavated by the drill and blast method, constructed sequentially from inside the station outwards, and the multi-level bench method is used for cyclic construction.

[0005] Preferably, the multi-level bench method construction is specifically as follows: the three-level bench method construction without a working platform frame for excavation and support is adopted, including the following steps:

[0006] First, divide the excavation section of the climbing section into three benches with equal height dimensions;

[0007] Secondly, construct the upper bench first. When constructing, reserve the core soil at its center as the support operation platform and the subsequent excavation operation platform. The height of the reserved core soil is half of the height of the upper bench, and then construct the initial support of the arch crown and side walls;

[0008] Thirdly, after the upper bench construction is completed, promptly construct the middle and lower benches. When constructing the middle and lower benches, also reserve the core soil at their centers as the support operation platform and the subsequent excavation operation platform, and then construct the initial support of the side walls;

[0009] Finally, excavate the reserved core soil at the center, and carry out the subsequent lining and other construction steps of the tunnel to complete the construction of the tunnel climbing section.

[0010] Preferably, the initial support includes: initial spraying of concrete, then supporting the anchor net system, and erecting a steel frame of matching shape, symmetrically driving locking foot anchors above the arch foot of the steel frame and close to the edges of both sides of the steel frame, welding them to the steel frame, and finally re-spraying concrete to a designed thickness. The locking foot anchors are perpendicular to the steel frame and the sides of the tunnel when driven. The locking foot anchors include an inner end anchor, a multi-section middle anchor, an outer end anchor, and a connecting sleeve for fixing adjacent anchors. The inner diameter of the connecting sleeve is slightly smaller than the outer diameter of the locking foot anchor. One end of the anchor rod is a tip for entering the soil, and the other end is set as a concave connecting groove. One end of the middle anchor rod is set as a concave connecting groove, and the other end is set as a connecting end matched with the connecting groove. One end of the outer anchor rod is set as a connecting end matched with the connecting groove, and the other end is a normal end. When the locking foot anchor rod is driven to the inside of the tunnel, it is driven in sections in sequence, and is assisted by an auxiliary rod during the driving. The auxiliary rod is a T-shaped structure, and the vertical part just fits in the connecting groove. The specific method of driving the locking foot anchor rod to the inside of the tunnel is as follows:

[0011] First, fit the vertical part of the auxiliary rod into the connection groove of the inner anchor rod, and put it outside the connection groove through the connection sleeve. After determining the driving position and angle, use the horizontal part of the auxiliary rod as the fulcrum to drive the inner anchor rod until only the connection groove of the inner anchor rod is located outside the tunnel.

[0012] Secondly, remove the auxiliary rod and the connecting sleeve, insert the connecting end of the middle anchor rod into the connecting groove of the inner end anchor rod, and put it outside the connecting groove through the connecting sleeve, fit the vertical part of the auxiliary rod into the connecting groove of the middle anchor rod, and put it outside the connecting groove through the connecting sleeve, and use the horizontal part of the auxiliary rod as the fulcrum to drive the middle anchor rod until only the connecting groove of the middle anchor rod is located outside the tunnel, and the driving of the middle anchor rod is along the straight line direction of the inner end anchor rod;

[0013] Again, repeat the above process until all the middle anchors are driven;

[0014] Finally, remove the auxiliary rod and the connecting sleeve, insert the connecting end of the outer anchor rod into the connecting groove of the middle anchor rod, and put the connecting sleeve outside the connecting groove, and directly use the normal end of the outer anchor rod as the fulcrum to drive the outer anchor rod. The outer anchor rod is driven until the normal end protrudes outside the tunnel, and the protruding part is welded to the steel frame, and the protruding part does not protrude beyond the thickness of the sprayed concrete.

[0015] Among them, after the connecting sleeves arranged between adjacent anchor rods are arranged outside the connecting groove, the two ends of the connecting sleeves are clamped by connecting clamps.

[0016] Preferably, the multi-step construction method is specifically: a two-step construction method with excavation support by a workbench is adopted, comprising the following steps:

[0017] First, construct the upper bench first. For excavation, arch erection, and other construction operations, an erection working platform is used. After excavation is completed, the tunnel face is supported by the excavated spoil to form a working platform for the tunnel face, assisting the construction of the upper bench.

[0018] Secondly, after the upper bench construction is completed, remove the spoil, and then carry out the lower bench construction. For excavation, arch erection, and other construction operations, an erection working platform is used. After excavation is completed, the tunnel face is supported by the excavated spoil to form a working platform for the tunnel face, assisting the construction of the lower bench.

[0019] Preferably, the erection working platform includes vertical poles, longitudinal horizontal bars, and transverse horizontal bars. According to the structure of the excavation section, the erection working platform is erected by the vertical poles, longitudinal horizontal bars, and transverse horizontal bars. The vertical poles, longitudinal horizontal bars, and transverse horizontal bars are detachably connected by buckles.

[0020] Preferably, after excavating a part of the bench, a stacking platform is formed by piling up the excavated soil and rock, and an excavator is used to tamp and level the stacking platform to form an installation platform. The erection working platform is erected on the installation platform.

[0021] Preferably, multiple safety bolts are pre-embedded in the side walls on the left and right sides of the tunnel face. They are connected to the erected erection working platform by welding or tying, and a safety net is hung on the inner side of the erection working platform for enclosure to stabilize the erection working platform.

[0022] Preferably, precast concrete pads are provided at the bottom of the erection working platform to ensure the stability of the erection working platform and prevent it from tipping outwards.

[0023] Preferably, temporary steps for personnel are provided at the bottom of the tunnel side, and safety handrails are provided at high positions. A spoil retaining wall is provided at the tunnel face to prevent falling stones or rolling stones from injuring people. The spoil retaining wall is made of a steel mesh and is used in cooperation with the pre-embedded bolts reserved in the tunnel side.

[0024] Preferably, during construction, the advance of the upper bench in each cycle does not exceed the spacing of 2 steel frames, and the advance of the middle and lower benches also does not exceed the spacing of 2 steel frames. The excavation of the middle and lower benches is staggered by at least 5 meters.

[0025] The present invention has at least the following beneficial effects:

[0026] 1. The first solution of the present invention adopts the three-bench construction method with a reserved core soil. The excavation section is small, the construction efficiency of excavation and support is high, the tunnel face can be timely supported, the cycle time is short, the reserved core soil plays a role in temporarily supporting the tunnel face operation, and the construction safety risk is effectively reduced.

[0027] 2. The first solution of the present invention adopts the construction method of three-step reserved core soil without using a working scaffold, which saves the process time of the working scaffold. At the same time, the working height of the upper step is low, making it convenient for personnel to operate.

[0028] 3. The second solution of the present invention adopts two-step construction, which has relatively high construction efficiency.

[0029] 4. For the second solution of the present invention, the stone slag formed by blasting is used for platform padding and slope repair, which saves the process time of slag removal. At the same time, when the slope is long, it can effectively reduce the slope of the upper step during excavation, meet the condition for the loader to go uphill, and the equipment transportation efficiency is higher. The slope reduction can effectively avoid rolling stones from hurting people, and it is safer and more convenient for personnel to go up and down.

[0030] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a sectional view of the excavation of the three-step reserved core soil in the climbing section of the present invention;

[0032] Figure 2 It is a schematic structural view of the locking foot bolt of the present invention;

[0033] Figure 3 It is a schematic view of the stacking on the construction platform in the climbing section of the present invention;

[0034] Figure 4 It is a schematic structural view of the erection of the working scaffold of the present invention;

[0035] Figure 5 It is a schematic view of the setting of the concrete cushion block of the present invention.

[0036] Explanation of the reference numerals in the drawings:

[0037] 1. Reserved core soil, 2. Face, 3. Erection working scaffold, 4. Stacking platform, 5. Concrete cushion block, 6. Inner end bolt, 7. Middle bolt, 8. Outer end bolt, 9. Connection groove, 10. Connection end, 11. Connection sleeve. DETAILED DESCRIPTION OF THE INVENTION

[0038] The following further detailed description of the present invention is made with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0039] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plans are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained through commercial channels; in the description of the present invention, the terms "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

[0040] The present invention provides a construction technology for invert cut-and-cover tunneling in the climbing section of a tunnel. The excavation in the climbing section is constructed by the drill and blast method, and the construction is carried out sequentially from inside the station to the outside, using the multi-level bench method for cyclic construction. In actual construction, considering that equipment other than excavators cannot enter the construction due to a 30° large slope, a total of 2 excavation and support schemes are adopted in the actual construction process.

[0041] The first scheme is: the three-level bench method of excavation and support without a working scaffold is adopted for construction.

[0042] The excavation method in the climbing section is optimized and adjusted, and the construction method of three benches + reserved core soil 1 is adopted, which specifically includes the following steps:

[0043] First, the excavation section in the climbing section is divided into three benches with equal height dimensions;

[0044] Secondly, as Figure 1 shown, first construct the upper bench. During construction, reserve core soil 1 at its center as a support working platform and subsequent excavation working platform, reduce the use of a working scaffold for construction. The height of the reserved core soil 1 is half of the height of the upper bench, and then construct the initial support for the arch crown and side walls;

[0045] Thirdly, after the construction of the upper bench is completed, promptly carry out the construction of the middle and lower benches. During the construction of the middle and lower benches, also reserve core soil 1 at their center as a support working platform and subsequent excavation working platform, and then construct the initial support for the side walls;

[0046] Finally, excavate the reserved core soil 1 at the center, and carry out subsequent lining and other construction steps of the tunnel to complete the construction of the tunnel climbing section.

[0047] In the above technical solution, the construction technology has the following advantages: ① In the construction of three benches with reserved core soil 1, the excavation section is small, the excavation and support construction efficiency is high, the heading face 2 can be supported in a timely manner, the cycle time is short, and the reserved core soil 1 plays a role in temporarily supporting the operation of the heading face 2, effectively reducing the construction safety risk; ② There is no need for a working scaffold for construction, saving the process time of the working scaffold. At the same time, the working height of the upper bench is low, which is convenient for personnel operation.

[0048] In another technical solution, Figure 2 As shown, the initial support includes: initial spraying of concrete, then supporting the anchor net system, and setting up a steel frame of matching shape, symmetrically driving locking foot anchor rods above the arch foot of the steel frame close to the edges of both sides of the steel frame, welding them to the steel frame, and finally re-spraying concrete to the designed thickness. When driving, the locking foot anchor rods are perpendicular to the steel frame and the side of the tunnel. The locking foot anchor rods include an inner end anchor rod 6, a multi-section middle anchor rod 7, an outer end anchor rod 8 and a connecting sleeve 11 for fixing adjacent anchor rods. The inner diameter of the connecting sleeve 11 is slightly smaller than the outer diameter of the locking foot anchor rod. One end of the inner end anchor rod 6 The middle anchor rod 7 has one end which is set as the concave connecting groove 9, and the other end is set as the connecting end 10 which matches the connecting groove 9. The outer anchor rod 8 has one end which is set as the connecting end 10 which matches the connecting groove 9, and the other end is the normal end. When the locking foot anchor rod is driven to the inside of the tunnel, it is driven in sections in sequence, and is assisted by an auxiliary rod. The auxiliary rod is a T-shaped structure, and the vertical part just matches in the connecting groove 9. The specific method of driving the locking foot anchor rod to the inside of the tunnel is as follows:

[0049] First, fit the vertical part of the auxiliary rod into the connection groove 9 of the inner end anchor rod 6, and put it outside the connection groove 9 through the connection sleeve 11. After determining the driving position and angle, use the horizontal part of the auxiliary rod as the fulcrum to drive the inner end anchor rod 6 until only the connection groove 9 of the inner end anchor rod 6 is located outside the tunnel.

[0050] Secondly, remove the auxiliary rod and the connecting sleeve 11, and insert the connecting end 10 of the middle anchor rod 7 into the connecting groove 9 of the inner end anchor rod 6, and sleeve the connecting sleeve 11 outside the connecting groove 9, fit the vertical part of the auxiliary rod into the connecting groove 9 of the middle anchor rod 7, and sleeve the connecting sleeve 11 outside the connecting groove 9, and use the horizontal part of the auxiliary rod as the fulcrum to drive the middle anchor rod 7 until only the connecting groove 9 of the middle anchor rod 7 is located outside the tunnel, and the driving of the middle anchor rod 7 is along the straight line direction of the inner end anchor rod 6;

[0051] Again, repeat the above process until all the middle anchor rods 7 are driven;

[0052] Finally, the auxiliary rod and the connecting sleeve 11 are removed, and the connecting end 10 of the outer anchor rod 8 is inserted into the connecting groove 9 of the middle anchor rod 7, and the connecting sleeve 11 is sleeved outside the connecting groove 9, and the outer anchor rod 8 is directly driven with the normal end of the outer anchor rod 8 as the fulcrum. The outer anchor rod 8 is driven until the normal end protrudes outside the tunnel, and the protruding part is welded to the steel frame, and the protruding part does not protrude beyond the thickness of the sprayed concrete.

[0053] Among them, after the connecting sleeve 11 arranged between adjacent anchor rods is sleeved outside the connecting groove 9, the two ends of the connecting sleeve 11 are clamped tightly by connecting clamps.

[0054] In the above technical solution, since the excavation section of the upper bench is small and the reserved core soil 1 occupies part of the space, it is difficult for personnel to operate in the limited free space. Therefore, it is necessary to strengthen the construction quality control of the foot-locking anchor rods. If the foot-locking anchor rods are directly driven, it is not easy to control the angle. Therefore, in this application, the foot-locking anchor rods are set as multiple sections and driven in multiple segments. Without affecting the overall efficacy of the foot-locking anchor rods, it can better adapt to the construction in a small space. Only by positioning the position and angle of the inner-end anchor rod 6 and successfully driving the inner-end anchor rod 6, the subsequent multiple middle-section anchor rods 7 and outer-end anchor rods 8 can be driven along the straight line of the inner-end anchor rod 6, so that the entire foot-locking anchor rods can be simply and efficiently driven and constructed in a small space. The normal end of the outer-end anchor rod 8, that is, the anchor rod, does not undergo any form of change. The shape of the connecting groove 9 can be adjusted according to the actual processing conditions. The purpose is to ensure that the auxiliary rod and the connecting end 10 can be successfully matched, which is convenient for driving and firmly connected. If adjacent anchor rods are directly connected and then erected, the length is relatively long. Therefore, an auxiliary rod is provided for auxiliary erection, which can reduce the construction length, thereby reducing the construction space to meet the conditions of actual small-space operation. At the same time, more space can be vacated for other construction operations.

[0055] The steel frame segments and between the steel frames should be promptly and firmly connected. Bolts are used for connection, and the connecting steel plates are welded around three sides. The voids behind the steel frames must be filled densely with shotcrete, and it is strictly prohibited to fill with other materials such as rubble behind; after the installation of the steel frame is completed, the foot-locking anchor rods should be promptly constructed and firmly connected to them.

[0056] The second solution is: adopting the two-level bench method construction with an operation bench for excavation and support.

[0057] It includes the following steps:

[0058] First, as Figure 3 shown, first construct the upper bench. Excavation, arch erection and other construction operations are all carried out using the erection operation bench 3. After the excavation is completed, the face 2 is supported by the excavated stone slag to form a working platform for the face 2 to assist the construction of the upper bench;

[0059] Secondly, after the construction of the upper bench is completed, the muck is removed, and then the lower bench is constructed. Excavation, arch erection and other construction operations are all carried out using the erection operation bench 3. After the excavation is completed, the face 2 is supported by the excavated stone slag to form a working platform for the face 2 to assist the construction of the lower bench.

[0060] In the above technical scheme, the two-step construction has the following advantages: ①Higher construction efficiency; ②The slag formed by blasting is used to support the platform and repair the slope, saving the slag removal process time. At the same time, when the slope is long, it can effectively reduce the uphill slope when excavating the upper steps, meet the conditions for the loader to go uphill, and use equipment for transportation efficiency is more efficient; ③The reduction of the slope can effectively prevent rolling stones from injuring people, and it is safer and more convenient for people to go up and down. The slag removal of the climbing section is carried out by an excavator, and the slag of the climbing section is transferred to the straight section at the bottom. The loader is located in the straight section for centralized transfer.

[0061] In another technical solution, Figure 4 As shown, the stand work platform 3 includes vertical poles, longitudinal horizontal poles and transverse horizontal poles. According to the structure of the excavation section, the stand work platform 3 is erected by the vertical poles, longitudinal horizontal poles and transverse horizontal poles, and the vertical poles, longitudinal horizontal poles and transverse horizontal poles are detachably connected by buckles. According to the actual structural dimensions of the excavation section of the upper and lower steps of the entrance and exit, the framework of the scaffolding is determined. A single-tube vertical pole fastener scaffolding is used for erection, and the steel pipe has a diameter of 42mm and a wall thickness of 3.5mm. The stand work platform 3 is mainly composed of a steel frame composed of vertical poles, longitudinal and transverse horizontal poles connected by fasteners. A steel pipe bracket is used to set up the platform to improve the quality of bracket erection and reduce the risk of bracket collapse. The excavation section is large, and the stand work platform 3 is erected quickly, which can control the support time and avoid the face 2 from being exposed for too long.

[0062] In another technical solution, after excavating part of the steps, a stacking platform 4 is formed by piling up the excavated soil, and the stacking platform 4 is compacted and leveled with an excavator to form a placing platform, and a vertical frame work platform 3 is erected on the placing platform to ensure the stability of the erection of the vertical frame work platform 3.

[0063] In another technical solution, multiple safety anchors are embedded in the side walls on the left and right sides of the face 2, which are connected to the erected work platform 3 by welding or binding, and a safety net is hung inside the work platform 3 to close it, so as to stabilize the work platform 3. Safety anchors are embedded in the left and right side walls near the face 2, and exposed for at least 50 cm, as a wall-connecting stabilizing bracket for the platform work frame. For the fastener-type steel pipe external scaffolding, a dense mesh safety net is hung vertically to close it along the inner side of the external frame, and the safety nets are firmly connected and fixed to the frame.

[0064] In another technical solution, Figure 5As shown in the figure, precast concrete pads 5 are provided at the bottom of the erection working platform 3 to ensure the stability of the erection working platform 3 and prevent it from tipping outwards. When using a support for excavation operations, the thrust generated by the drilling of the drill rig is likely to cause a risk of the support tipping outwards. Therefore, the precast concrete pads 5 solve this problem well. The cross-section of the climbing section is in a 30° slope area. The erection working platform 3 for the support operation is supported by the precast concrete pads 5 to ensure the stability of the erection working platform 3. The concrete pads 5 are selected according to the slope of the slope surface.

[0065] In the first and second solutions described above, during the construction of the climbing section, in order to achieve safety protection, it can be controlled from the following two aspects:

[0066] (1) In order to ensure the safety of the operators going up and down, a temporary step of 0.8 - 1.2 m needs to be set on the right side of the tunnel, and a safety handrail needs to be welded at a height of 1.2 m on the side wall.

[0067] (2) During the operation process, a slag retaining wall needs to be set at a distance of 25 - 10 m from the heading face to prevent falling stones or rolling stones from injuring people; the slag retaining wall is made of a steel mesh sheet and needs to be used in cooperation with the reserved anchor bolts on the side wall during use.

[0068] In the first and second solutions described above, during construction, the advance of the upper bench in each cycle does not exceed the spacing of 2 steel frames, and the advance of the middle and lower benches also does not exceed the spacing of 2 steel frames. The excavation of the middle and lower benches is staggered by at least 5 meters. During the construction of the climbing section of the auxiliary entrance and exit, the advance in each cycle is strictly controlled. The advance of the upper bench in each cycle does not exceed the spacing of 2 steel frames, the advance in each cycle of the exit section does not exceed the spacing of 1 steel frame, and the advance of the middle and lower benches in each cycle shall not exceed the spacing of 2 steel frames. After the lower part is excavated, the steel frames should be extended and lowered in time. It is strictly prohibited for the bottom feet of the steel frames to be suspended and for the two sides to be excavated and extended simultaneously. The left and right sides need to be staggered by at least 5 meters to avoid the arch feet being suspended simultaneously.

[0069] Although the implementation schemes of the present invention have been disclosed as above, they are not limited to only the applications listed in the description and implementation modes. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated and described examples here.

Claims

1. A construction technology for invert excavation in the uphill section of a tunnel, characterized in that, The excavation of the climbing section adopts the drilling and blasting method, which is carried out from the inside of the station to the outside, and adopts the multi-step method for cyclic construction; The multi-step construction method is specifically: the three-step construction method without working platform excavation support is adopted, including the following steps: First, the excavation section of the climbing section is divided into three steps with equal height dimensions; Secondly, the upper step is constructed first. During construction, core soil is reserved in the center as a support working platform and subsequent excavation working platform. The height of the reserved core soil is half of the height of the upper step. Then, the initial support of the vault and side walls is constructed. Thirdly, after the construction of the upper step is completed, the construction of the middle and lower steps should be carried out in time. During the construction of the middle and lower steps, core soil should be reserved in the center as a support working platform and subsequent excavation working platform, and then the initial support of the side wall should be constructed; Finally, the core soil is reserved in the excavation center, and the subsequent lining and other construction steps of the tunnel are carried out to complete the construction of the climbing section of the tunnel; The initial support includes: initial spraying of concrete, then supporting the anchor net system, and setting up a steel frame of matching shape. Above the arch foot of the steel frame, close to the edges of both sides of the steel frame, symmetrically driving the locking foot anchor rods, which are welded to the steel frame, and finally re-spraying concrete to the designed thickness. When driving, the locking foot anchor rods are perpendicular to the steel frame and the side of the tunnel. The locking foot anchor rods include inner end anchor rods, multi-section middle anchor rods, outer end anchor rods and connecting sleeves for fixing adjacent anchor rods. The inner diameter of the connecting sleeve is slightly smaller than the outer diameter of the locking foot anchor rod. One end of the inner end anchor rod is The tip of the anchor rod is set to the ground, and the other end is set to the concave connecting groove. One end of the middle anchor rod is set to the concave connecting groove, and the other end is set to the connecting end matched with the connecting groove. One end of the outer anchor rod is set to the connecting end matched with the connecting groove, and the other end is the normal end. When the locking foot anchor rod is driven to the inside of the tunnel, it is driven in sections in sequence, and is assisted by an auxiliary rod during the driving. The auxiliary rod is a T-shaped structure, and the vertical part just fits in the connecting groove. The specific method of driving the locking foot anchor rod to the inside of the tunnel is as follows: First, fit the vertical part of the auxiliary rod into the connection groove of the inner anchor rod, and put it outside the connection groove through the connection sleeve. After determining the driving position and angle, use the horizontal part of the auxiliary rod as the fulcrum to drive the inner anchor rod until only the connection groove of the inner anchor rod is located outside the tunnel. Secondly, remove the auxiliary rod and the connecting sleeve, insert the connecting end of the middle anchor rod into the connecting groove of the inner end anchor rod, and put it outside the connecting groove through the connecting sleeve, fit the vertical part of the auxiliary rod into the connecting groove of the middle anchor rod, and put it outside the connecting groove through the connecting sleeve, and use the horizontal part of the auxiliary rod as the fulcrum to drive the middle anchor rod until only the connecting groove of the middle anchor rod is located outside the tunnel, and the driving of the middle anchor rod is along the straight line direction of the inner end anchor rod; Again, repeat the above process until all the middle anchors are driven; Finally, remove the auxiliary rod and the connecting sleeve, insert the connecting end of the outer anchor rod into the connecting groove of the middle anchor rod, and put the connecting sleeve outside the connecting groove, and directly use the normal end of the outer anchor rod as the fulcrum to drive the outer anchor rod. The outer anchor rod is driven until the normal end protrudes outside the tunnel, and the protruding part is welded to the steel frame, and the protruding part does not protrude beyond the thickness of the sprayed concrete. Among them, after the connecting sleeves arranged between adjacent anchor rods are arranged outside the connecting groove, the two ends of the connecting sleeves are clamped by connecting clamps.

2. The open cut tunneling construction process for the uphill section of a tunnel as described in claim 1, characterized in that, The multi-step construction method is specifically: the two-step construction method with excavation support by working platform is adopted, including the following steps: First, the upper steps are constructed. Excavation, arch erection and other construction are all carried out using a vertical work platform. After the excavation is completed, the excavated slag is used to support the tunnel face to form a tunnel face working platform to assist the construction of the upper steps. Secondly, after the construction of the upper step is completed, the slag is discharged and then the construction of the lower step is carried out. Excavation, arch erection and other construction are all carried out using a vertical work platform. After the excavation is completed, the face is supported by excavated slag to form a face working platform to assist the construction of the lower step.

3. The cut-and-cover tunneling construction technology for the uphill section of the tunnel as described in claim 2, characterized in that, The frame work platform includes vertical poles, longitudinal horizontal poles and transverse horizontal poles. According to the structure of the excavation section, the frame work platform is erected by the vertical poles, longitudinal horizontal poles and transverse horizontal poles. The vertical poles, longitudinal horizontal poles and transverse horizontal poles are detachably connected by buckles.

4. The construction process of the inverted excavation in the upward-sloping section of the tunnel as described in claim 2 is characterized in that, After excavating some steps first, the excavated debris is piled up to form a stacking platform, and the stacking platform is compacted and leveled with an excavator to form a placing platform, on which a frame work platform is erected.

5. The inverted excavation construction process for the uphill section of the tunnel as described in claim 2, characterized in that, Multiple safety anchor rods are embedded in the side walls on both sides of the face, which are connected to the erected stand work platform by welding or binding, and a safety net is hung on the inner side of the stand work platform to close it and stabilize it.

6. The cut-and-cover tunneling construction process for the upward-sloping section of a tunnel as described in claim 2, characterized in that, Prefabricated concrete pads are set at the bottom of the vertical work platform to ensure the stability of the vertical work platform and prevent it from tipping over.

7. The cut-and-cover tunneling construction technology for the uphill section of the tunnel as claimed in claim 1 or 2, characterized in that, Temporary steps for personnel are set at the bottom of the tunnel side, safety handrails are set at high places, and a ballast retaining wall is set at the heading face to prevent falling rocks or rolling stones from injuring people. The ballast retaining wall is made of steel mesh and is used in conjunction with anchor rods reserved in the side of the tunnel.

8. The cut-and-cover tunneling construction process for the uphill section of the tunnel as claimed in claim 1 or 2, characterized in that, During construction, the advancement of the upper steps in each cycle shall not exceed the spacing of 2 steel frames, and the advancement of the middle and lower steps shall not exceed the spacing of 2 steel frames. The excavation of the middle and lower steps shall be staggered by at least 5 meters.

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