A construction technology for underground subway station engineering

Abstract

The present invention belongs to the field of infrastructure technology, specifically a construction method for a subway underground excavation station project. The construction technology of the subway underground excavation station project is initially developed through research methods such as technical investigation, theoretical analysis and numerical simulation, advanced geological prediction, field experiments and field tests, induction and summary, technical refinement, and reference to a large number of foreign technologies. At the same time, the current status of similar engineering and technical research and application at home and abroad is also fully grasped. Furthermore, the causes of excavation accidents are analyzed. Based on various investigations and analyses, a detailed research outline and work plan are formulated. Furthermore, theoretical analysis and numerical simulation methods are used to study the surrounding rock stress redistribution and displacement distribution law and the force characteristics of the support structure during the pilot tunnel excavation process; so that the construction technology of the subway underground excavation station project in the present invention can be carried out quickly and safely step by step during execution, ensuring the completion time and quality.

Description

Technical Field

[0001] The invention belongs to the technical field of infrastructure, and in particular relates to a construction method for a subway underground excavation station project. Background Art

[0002] The rapid development of modern cities has led to increasing urban traffic congestion. Therefore, vigorously developing public transportation, especially rail transit, is an inevitable requirement for many large and metropolitan cities. In order to avoid further congestion in surface traffic during construction and conserve urban space resources, more and more subway stations are being constructed using the underground excavation method.

[0003] For example, Yong'anli Station is located on the north side of the intersection of Dongdaqiao Road and Jianguomenwai Avenue, and the main body of the station is arranged along Dongdaqiao Road in a north-south direction; the Yong'anli-Dongdaqiao section at the north end of the station is constructed using the mining method, and the Guangqumenwai Station-Yong'anli section at the south end is constructed using the shield method + mining method; the station has a total of 3 temporary construction shafts, temporary construction shaft No. 1 is located on the pedestrian walkway on the west side of Guiyou Building on the east side of Dongdaqiao Road; construction shaft No. 2 is combined with barrier-free elevator No. 2, located on the pedestrian walkway on the east side of Dongdaqiao Road, close to Building 1 Yong 5 and Building 1 Yong 1; temporary construction shaft No. 3 is combined with entrance and exit B, located on the east side of Dongdaqiao Road. The centerline mileage of the No. 1 temporary construction shaft and cross passage is K21+898.193. The clearance dimensions of the shaft body are 6.9m long and 4.6m wide. The excavation height of the cross passage section is 25.20m and the width is 4.7m. The thickness of the arch cover is about 4.537m.

[0004] At present, the auxiliary construction channel and the station transition section usually adopt the method of converting from the auxiliary construction channel footage to the station excavation. This method is difficult to construct, consumes a lot of temporary support, has high risks, and has a long construction period. At present, how to reasonably adjust the construction process of subway stations and improve and innovate the construction methods of construction channels and station tunnel transition sections has become one of the key issues of concern to engineers engaged in the rail transit industry.

[0005] To this end, the present invention provides a construction method for a subway underground excavation station project. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a construction method for a subway underground excavation station project, including an earth excavation construction method, and the earth excavation construction method includes the following steps:

[0008] Step 1: Set up a water-stop curtain at the location of the shaft to be excavated. After the construction of the water-stop curtain is completed, conduct temporary shaft excavation. When the shaft is excavated to a position 0.5m above the water level, conduct temporary bottom sealing. After the cross-passage horse head gate is reinforced, excavate the first and second-level cross passages.

[0009] Step 2: After the end of the cross passage is sealed and the advance support of the small pilot tunnel is completed, the upper pilot tunnels on both sides and the middle upper pilot tunnel are excavated;

[0010] Step 3: Excavate the middle and upper pilot tunnels, seal the ends, and then construct mechanical retaining piles, pile top crown beams, and side arch primary support backfill in the upper pilot tunnels;

[0011] Step 4: Carry out water-stop curtain in the second-floor transverse passage. After the water-stop curtain is formed, excavate the temporary construction shaft to the permanent bottom, and excavate the third, fourth, fifth and sixth-floor transverse passages;

[0012] Step 5: After the transverse passage is sealed, a deep hole grouting water-stop curtain with full section of the lower pilot tunnel is constructed in the transverse passages on the fifth and sixth floors. After the water-stop curtain is formed, the pilot tunnel gate is reinforced and the lower side pilot tunnel is excavated.

[0013] Step 6: After the lower side pilot tunnel is constructed for 15m, the lower middle pilot tunnel is excavated. After the pilot tunnel ends are sealed, the bottom longitudinal beam is constructed in the lower pilot tunnel;

[0014] Step 7: After the bottom longitudinal beam is constructed, the middle column hole and the segment column hole are manually excavated in the upper pilot hole. After the middle column hole and the segment column hole are constructed, the steel pipe column and the steel cage inside the column are installed. After the concrete of the steel pipe column is poured, the column top longitudinal beam is constructed;

[0015] Step 8: After the large arch pipe shed is completed in the transverse passage construction, the top longitudinal beam is completed, and after the initial support and arch door reinforcement of the transverse passage construction is completed, the AB span and CD span arch excavation is carried out;

[0016] Step 9: After the AB and CD spans have been excavated for 15m, the BC and DE spans will be excavated. After the primary support arch construction is completed, the secondary lining arch crown construction will be carried out;

[0017] Step 10: After the construction of the second lining arch is completed, the station hall layer is excavated downward in layers, and the station hall layer inter-pile sprayed anchor support and the middle plate, longitudinal beam, track top air duct and side wall structure are constructed;

[0018] Step 11: After the concourse structure reaches the designed strength, excavate the platform layer downwards and construct the platform layer inter-pile sprayed anchor support and bottom plate and side wall structures;

[0019] Preferably, in the temporary shaft excavation operation described in step 1, the shaft body is constructed using the inverted shaft wall method, and support is provided while excavating from top to bottom. The excavation method is half-width sequential excavation, first excavating part ①, excavating earth, erecting a grid frame, and spraying concrete, and then excavating part ②, excavating earth, erecting a grid frame, and spraying concrete to close the ring. The shaft excavation size is 6.2*7.6m, and the excavation step distance is 0.5m per grid frame.

[0020] Preferably, in the first support buckle arch door in step 8, only the first support buckle arch and the first support grid structure between the main guide tunnel are set up, and there is no need to close the lower arch into a ring. For this purpose, the upper step of the first support buckle arch adopts a low step for manual earth excavation and initial support structure construction, and the lower step adopts mechanical earth excavation;

[0021] The excavation parameters for the initial support arch guide tunnel are:

[0022] a. Mechanical earthwork is used for the lower steps. To prevent impact on the upper steps, the upper steps are initially reserved at a length of 5-8m. Based on the actual situation at the construction site, the lower steps will be excavated after the upper steps are completed.

[0023] b. The height between the upper step interface and the primary support arch is 1.5-1.7m, which is convenient for construction workers to carry out earth excavation and initial support construction;

[0024] c. The core package for the upper steps is reserved. The size of the core package for the middle span is 0.75m high and 2.7m wide; the size of the core package for the side span is 0.75m high and 3.6m wide;

[0025] d. When constructing the upper steps, reserve core soil with a height of no less than 0.3m and a length of no less than 1.7m;

[0026] e. The lower step is 2.65m high and is excavated by a small excavator. The excavated soil is directly loaded onto a tricycle for transport;

[0027] f. A 1.2m height earthwork is reserved at the bottom without construction to provide a foundation for the secondary lining structure construction trolley in the later stage;

[0028] The underground excavation method does not dig up the ground, but adopts the method of digging holes underground for construction. The mining method and the shield method are both underground excavation methods. Due to the uncertainty of the engineering hydrogeological conditions and the complexity of the construction environment, there are still many construction risks in the construction process of shallow buried underground excavation projects, and many risk accidents have occurred. Therefore, before excavation, it is necessary to carefully design the excavation technology and sequence; the construction technology of the subway underground excavation station project provided in the present invention has been studied in the early stage through technical research, theoretical analysis and numerical simulation, advanced geological prediction, field experiments and field tests, induction and summary, technical refinement and other research methods, as well as drawing on a large number of foreign technologies, and also investigating and fully mastering the current The research and application status of similar projects and technologies at home and abroad, and the causes of excavation accidents were analyzed. Based on various investigations and analyses, a detailed research outline and work plan were formulated. Theoretical analysis and numerical simulation methods were used to study the stress redistribution and displacement distribution law of the surrounding rock during the excavation of the pilot tunnel, and the stress characteristics of the support structure; the stress redistribution superposition law and the distribution of the plastic zone of the surrounding rock under the group tunnel effect were explored; the effects of different construction steps and intermediate rock column reinforcement schemes were compared; the construction methods and construction schemes were optimized; so that the construction technology of the subway underground excavation station project in the present invention can be carried out quickly and safely, ensuring the completion time and quality.

[0029] Preferably, the grid frame comprises a plurality of arc-shaped grid plates; a base block is symmetrically fixed to the inner concave surface of the upper end of the grid plate, a No. 1 plate is connected to the base block, and the base block is rotatably connected to one end of the No. 1 plate, the other end of the No. 1 plate is threadedly connected to one end of a screw, and the other end of the screw is rotatably connected to a hook, and the angle at the corner position of the hook is 60-80 degrees; each grid plate is provided with a pin; the pin is T-shaped, and the long end of the pin passes through the upper through hole of the grid plate and is embedded in the side wall of the shaft; in the early stage of station excavation, the shaft is first excavated, The role of the shaft here is to increase the working surface or set up parallel pilot pits to facilitate the construction. During the excavation of the shaft, the inner wall of the shaft needs to be protected to prevent the loose soil from causing landslide accidents, and secondly, to prevent the side wall undercurrent from flowing into the shaft and causing internal flooding accidents. At present, the inverted shaft wall method is used for the construction of the shaft, which is excavated and supported from top to bottom. The grid plates are hoisted into the shaft by hoisting equipment and then fixed on the inner wall of the shaft. When the grid plates are fixed, it is difficult to align the upper and lower grid plates, resulting in the upper and lower grid plates being stuck. The gap is large, and when spraying concrete, it is difficult for concrete to adhere, resulting in weak concrete spraying in the gap, and the upper and lower grid plates are separated. Later, when the concrete is sprayed and solidified, it is relatively fragile; in the process of lowering the construction materials into the shaft in the later stage, they collide with the grid plates, and the grid plates are easy to loosen and separate; to solve the above problems, the present invention cooperates with the screw and the hook. After the upper grid plate is fixed on the side wall of the shaft, when installing the lower grid plate, the lower grid plate is pre-placed close to the upper grid plate, and then the lower grid plate is fixed to the side wall of the shaft. The No. 1 plate on the grid plate is rotated to the upper grid plate, and then the hook is inserted into the upper grid plate. Then the screw is rotated, and the screw pulls the lower grid plate upward, so that the upper and lower grid plates are close to each other and attached together, reducing the gap between the upper and lower grid plates. Then, the nails are inserted into the through holes on the grid plates and knocked into the inner wall of the shaft; the close attachment between the upper and lower grid plates improves the spraying and adhesion effect of concrete, helps to stably install the grid components, and enhances the performance of the grid components in resisting external collision forces.

[0030] Preferably, the pin includes a short plate and two rods, the rods are arranged separately, one end of the rod is fixed to the middle position of the short plate, and a recess is provided on the outer side of one end of the rod, and the recess cooperates with the inner side wall of the through hole on the grid plate; the pin is embedded in the through hole on the grid plate. Since the rods are arranged separately, the two rods are respectively inserted into one through hole. When the short plate is attached to the grid plate, the side wall of the through hole on the grid plate is embedded in the recess, clamping the rod to stabilize it, thereby improving the stability between the pin and the grid plate, and the sharp parts on both sides of the short plate are also inserted into the through holes on the grid plate. After that, concrete is sprayed to cover the pin on the grid plate, further improving the stability between the pin and the grid plate.

[0031] Preferably, a column-shaped hollow portion is provided inside the rod body, and a plurality of overflow holes are provided on the outer wall of the rod body, the overflow holes are communicated with the hollow portion, a column-shaped aluminum foil bag body is provided in the hollow portion, the bag body contains glue, a drawstring is fixed to the aluminum foil bag body, the drawstring is fixed to a portion of the aluminum foil bag body away from the recess, the other end of the drawstring passes through the inner side of the recess to provide a slide groove, a slider is provided at the notch of the slide groove, the slider is slidably clamped in the notch of the slide groove, and the other end of the drawstring is fixed; after the pin is inserted into the inner wall of the shaft, the through-hole side wall on the grid plate squeezes Slider, squeeze the slider toward the short plate, and at the same time, the slider pulls the aluminum foil bag through the pull rope, and the aluminum foil bag is torn open. At this time, the glue in the aluminum foil bag overflows. The glue is the same as the glue in the chemical expansion screw. The glue is discharged along the overflow hole and flows on the outer ring of the rod body, bonding the rod body to the inner wall of the vertical shaft to improve its stability. At the same time, part of the glue flows along the hollow part of the rod body into the slide groove, bonding and fixing the slider, and bonding to the inner wall of the through hole, further improving the connection strength between the pin and the grid plate.

[0032] Preferably, a baffle is provided in each through hole of the grid plate, the lower end of the baffle is vertically fixed to the inner bottom surface of the through hole, is arranged close to the inner concave surface of the grid plate, and a gap is left between the upper end of the baffle and the inner top surface of the through hole; the inner bottom surface of the through hole on the grid plate is horizontal, and after the concrete is sprayed, it is difficult for the concrete to stay in the through hole, and multiple sprayings of concrete are required; for this reason, a baffle is provided in the through hole of the grid plate, and after the concrete is sprayed on the grid plate, the concrete enters the through hole along the gap between the upper end of the baffle and the inner top surface of the through hole, and then the concrete stays in the through hole and solidifies on the inner side wall of the shaft, forming horizontal concrete support rods the size of the through hole, supporting the grid plate on the side wall of the shaft, thereby improving the stability of the grid plate.

[0033] Preferably, the grid plate is evenly provided with a plurality of insertion holes, the insertion holes are arranged at an angle downward, and the inclination direction is from the concave surface of the grid plate to the outer wall of the grid plate, the pins are inserted into the insertion holes, and the short plates on the pins are provided with inclined surfaces, and the inclined surfaces are adapted to the concave surface of the grid plate; the insertion holes are provided on the grid plate, and the inclination of the insertion holes allows the pins to be inserted into the insertion holes in an inclined state, thereby improving the firmness of the grid plate; the short plates are provided with inclined surfaces, the rod body is inserted into the inner wall of the shaft, and the inclined surfaces of the end plates are attached to the concave surface of the grid plate, thereby increasing the attachment surface between the pins and the grid plate and improving stability.

[0034] Preferably, a rotating hole is provided on the back side of the corner of the hook, and the rotating hole is provided along the end direction of the hook. A rotating rod is provided in the rotating hole, and a guide groove is provided on the inclined bottom surface of the hook. The guide groove is provided with a buckle, one end of the buckle is threadedly connected to the rotating rod, and the other end of the buckle is inclined to point to the vertical rod part of the hook; the hook is inserted into the upper grid plate, and then the rotating rod is rotated, and the rotating rod pulls the buckle, and the buckle approaches the outer surface of the grid plate and is squeezed on the outer surface of the grid plate, thereby enhancing the stability between the hook and the upper grid plate, thereby improving the stability between the upper and lower grid plates.

[0035] Preferably, the upper edge of the grid plate is set to be convex, and the lower edge of the grid plate is set to be concave; the screw is rotated, and the lower grid plate moves upward. At this time, the convex part of the upper edge of the lower grid plate is embedded in the concave position of the lower edge of the upper grid plate, which constrains the positions of the upper and lower grid plates and prevents the upper and lower grid plates from being misaligned, resulting in an uneven inner surface of the grid component, which affects the lowering and removal of materials in the vertical shaft.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. The construction method of a subway underground excavation station project described in the present invention, the construction technology of the subway underground excavation station project in the present invention, in the early stage, through technical investigation, theoretical analysis and numerical simulation, advanced geological prediction, field experiment and field test, induction and summary, technology refinement and other research means, and drawing on a large number of foreign technologies, also at the same time, the current research and application status of similar projects and technologies at home and abroad are fully grasped, and the causes of excavation accidents are analyzed. Based on various investigations and analyses, a detailed research outline and work plan are formulated, and theoretical analysis and numerical simulation methods are used to study the surrounding rock stress redistribution and displacement distribution law during the pilot tunnel excavation process, and the force characteristics of the support structure, so that the construction technology of the subway underground excavation station project in the present invention can be carried out quickly and safely during execution, ensuring the completion time and quality.

[0038] 2. The construction method of a subway underground station project described in the present invention is to insert a hook into the upper grid plate, and then rotate the screw, which pulls the lower grid plate upward, so that the upper and lower grid plates are close to each other and attached together, reducing the gap between the upper and lower grid plates, and then insert the nails into the through holes on the grid plates, and knock the nails into the inner wall of the shaft; the close attachment between the upper and lower grid plates improves the spraying and adhesion effect of concrete, helps to stabilize the installation of the grid components, and enhances the performance of the grid components in resisting external collision forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] Figure 1It is a construction flow chart of the underground excavation station project of the present invention;

[0041] Figure 2 It is a side view schematically showing the overall construction sequence of earth excavation in the present invention;

[0042] Figure 3 This is a schematic front view of the overall construction sequence of earth excavation in the present invention;

[0043] Figure 4 It is a plan view of the shaft excavation in the present invention;

[0044] Figure 5 It is a three-dimensional diagram of the grid structure of the present invention;

[0045] Figure 6 is a three-dimensional diagram of the grid plate of the present invention;

[0046] Figure 7 It is a three-dimensional diagram of the pin in the present invention;

[0047] Figure 8 is a cross-sectional view of the pin of the present invention;

[0048] Figure 9 This is a cross-sectional view of the mating of the pin and the socket in the present invention;

[0049] Figure 10 is a cross-sectional view of a hook according to the present invention;

[0050] Figure 11 This is a diagram showing the edges of the upper and lower grid plates of the present invention;

[0051] In the figure: grid plate 1, No. 1 plate 2, screw 21, hook 3, nail 4, short plate 5, rod body 6, recess 7, overflow hole 8, aluminum foil bag body 9, pull rope 10, slide groove 11, slider 12, baffle 13, socket 14, rotating rod 15, guide groove 16, buckle 17. DETAILED DESCRIPTION

[0052] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0053] Example 1:

[0054] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 A construction method for a subway underground station project includes an earth excavation construction method, and the earth excavation construction method includes the following steps:

[0055] Step 1: Set up a water-stop curtain at the location of the shaft to be excavated. After the construction of the water-stop curtain is completed, conduct temporary shaft excavation. When the shaft is excavated to a position 0.5m above the water level, conduct temporary bottom sealing. After the cross-passage horse head gate is reinforced, excavate the first and second-level cross passages.

[0056] Step 2: After the end of the cross passage is sealed and the advance support of the small pilot tunnel is completed, the upper pilot tunnels on both sides and the middle upper pilot tunnel are excavated;

[0057] Step 3: Excavate the middle and upper pilot tunnels, seal the ends, and then construct mechanical retaining piles, pile top crown beams, and side arch primary support backfill in the upper pilot tunnels;

[0058] Step 4: Carry out water-stop curtain in the second-floor transverse passage. After the water-stop curtain is formed, excavate the temporary construction shaft to the permanent bottom, and excavate the third, fourth, fifth and sixth-floor transverse passages;

[0059] Step 5: After the transverse passage is sealed, a deep hole grouting water-stop curtain with full section of the lower pilot tunnel is constructed in the transverse passages on the fifth and sixth floors. After the water-stop curtain is formed, the pilot tunnel gate is reinforced and the lower side pilot tunnel is excavated.

[0060] Step 6: After the lower side pilot tunnel is constructed for 15m, the lower middle pilot tunnel is excavated. After the pilot tunnel ends are sealed, the bottom longitudinal beam is constructed in the lower pilot tunnel;

[0061] Step 7: After the bottom longitudinal beam is constructed, the middle column hole and the segment column hole are manually excavated in the upper pilot hole. After the middle column hole and the segment column hole are constructed, the steel pipe column and the steel cage inside the column are installed. After the concrete of the steel pipe column is poured, the column top longitudinal beam is constructed;

[0062] Step 8: After the large arch pipe shed is completed in the transverse passage construction, the top longitudinal beam is completed, and after the initial support and arch door reinforcement of the transverse passage construction is completed, the AB span and CD span arch excavation is carried out;

[0063] Step 9: After the AB and CD spans have been excavated for 15m, the BC and DE spans will be excavated. After the primary support arch construction is completed, the secondary lining arch crown construction will be carried out;

[0064] Step 10: After the construction of the second lining arch is completed, the station hall layer is excavated downward in layers, and the station hall layer inter-pile sprayed anchor support and the middle plate, longitudinal beam, track top air duct and side wall structure are constructed;

[0065] Step 11: After the station hall structure reaches the designed strength, excavate the platform layer downwards and construct the platform layer inter-pile sprayed anchor support and bottom plate and side wall structure;

[0066] Reference Figure 2 and Figure 4, the temporary shaft excavation operation described in step 1, the shaft body is constructed using the inverted shaft wall method, and support is provided while excavating from top to bottom. The excavation method is half-width sequential excavation, first excavating part ①, excavating earthwork, erecting grid frame, and spraying concrete, then carrying out part ② excavation construction, excavating earthwork, erecting grid frame, and spraying concrete to close the ring. The shaft excavation size is 6.2*7.6m, and the excavation step distance is 0.5m per grid frame.

[0067] Reference Figure 3 , the initial support buckle arch door in step 8 only sets up the initial support buckle arch and initial support grid structure between the main guide tunnels, and there is no need to close the lower arch into a ring. For this reason, the upper step of the initial support buckle arch adopts a low step for manual earth excavation and initial support structure construction, and the lower step adopts mechanical earth excavation;

[0068] The excavation parameters for the initial support arch guide tunnel are:

[0069] a. Mechanical earthwork is used for the lower steps. To prevent impact on the upper steps, the upper steps are initially reserved at a length of 5-8m. Based on the actual situation at the construction site, the lower steps will be excavated after the upper steps are completed.

[0070] b. The height between the upper step interface and the primary support arch is 1.5-1.7m, which is convenient for construction workers to carry out earth excavation and initial support construction;

[0071] c. The core package for the upper steps is reserved. The size of the core package for the middle span is 0.75m high and 2.7m wide; the size of the core package for the side span is 0.75m high and 3.6m wide;

[0072] d. When constructing the upper steps, reserve core soil with a height of no less than 0.3m and a length of no less than 1.7m;

[0073] e. The lower step is 2.65m high and is excavated by a small excavator. The excavated soil is directly loaded onto a tricycle for transport;

[0074] f. A 1.2m height earthwork is reserved at the bottom without construction to provide a foundation for the secondary lining structure construction trolley in the later stage;

[0075] The underground excavation method does not dig up the ground, but adopts the method of digging holes underground for construction. The mining method and the shield method are both underground excavation methods. Due to the uncertainty of the engineering hydrogeological conditions and the complexity of the construction environment, there are still many construction risks in the construction process of shallow buried underground excavation projects, and many risk accidents have occurred. Therefore, before excavation, it is necessary to carefully design the excavation technology and sequence; the construction technology of the subway underground excavation station project provided in the present invention has been studied in the early stage through technical research, theoretical analysis and numerical simulation, advanced geological prediction, field experiments and field tests, induction and summary, technical refinement and other research methods, as well as drawing on a large number of foreign technologies, and also investigating and fully mastering the current The research and application status of similar projects and technologies at home and abroad, and the causes of excavation accidents were analyzed. Based on various investigations and analyses, a detailed research outline and work plan were formulated. Theoretical analysis and numerical simulation methods were used to study the stress redistribution and displacement distribution law of the surrounding rock during the excavation of the pilot tunnel, and the stress characteristics of the support structure; the stress redistribution superposition law and the distribution of the plastic zone of the surrounding rock under the group tunnel effect were explored; the effects of different construction steps and intermediate rock column reinforcement schemes were compared; the construction methods and construction schemes were optimized; so that the construction technology of the subway underground excavation station project in the present invention can be carried out quickly and safely, ensuring the completion time and quality.

[0076] Reference Figure 5 and Figure 6The grid frame includes a plurality of arc-shaped grid panels 1; a base block is symmetrically fixed to the inner concave surface of the upper end of the grid panel 1, a No. 1 plate 2 is connected to the base block, and the base block is rotatably connected to one end of the No. 1 plate 2, and the other end of the No. 1 plate 2 is threadedly connected to one end of the screw 21, and the other end of the screw 21 is rotatably connected to a hook 3, and the angle at the corner position of the hook 3 is 60-80 degrees; each grid panel 1 is provided with a pin 4; the pin 4 is T-shaped, and the long end of the pin 4 passes through the upper through hole of the grid panel 1 and is embedded in the side wall of the shaft; in the early stage of station excavation, the vertical shaft is first excavated. The role of the shaft here is to increase the working surface or set up a parallel pilot pit to facilitate the construction. During the excavation of the shaft, the inner wall of the shaft needs to be protected to prevent the loose soil from causing a landslide accident, and secondly, to prevent the side wall undercurrent from flowing into the shaft and causing an internal flooding accident. At present, the inverted shaft wall method is used for the construction of the shaft, which is excavated and supported from top to bottom. The grid plate 1 is hoisted into the shaft by hoisting equipment and then fixed on the inner wall of the shaft. When the grid plate 1 is fixed, it is difficult to align the upper and lower grid plates 1, resulting in a large gap between the upper and lower grid plates 1. When spraying concrete, it is difficult for the concrete to adhere, resulting in weak concrete spraying in the gaps, and the upper and lower grid plates 1 are separated, and are relatively fragile when sprayed and solidified later; in the process of lowering the construction materials into the shaft, they collide with the grid plates 1, and the grid plates 1 are easily loosened and separated; to address the above problems, the present invention cooperates with the screw 21 and the hook 3, and after the upper grid plate 1 is fixed on the side wall of the shaft, when installing the lower grid plate 1, the lower grid plate 1 is preliminarily placed close to the upper grid plate 1, and then the lower grid plate 1 is The upper plate 2 is rotated onto the upper grid plate 1, and then the hook 3 is inserted into the upper grid plate 1, and then the screw 21 is rotated. The screw 21 pulls the lower grid plate 1 upward, so that the upper and lower grid plates 1 are close to each other and attached together, reducing the gap between the upper and lower grid plates 1, and then the nails 4 are inserted into the through holes on the grid plate 1, and the nails 4 are knocked into the inner wall of the shaft; the close attachment between the upper and lower grid plates 1 improves the spraying and adhesion effect of concrete, helps to stably install the grid components, and enhances the performance of the grid components in resisting external collision forces.

[0077] Reference Figure 7 and Figure 8The pin 4 includes a short plate 5 and two rods 6. The rods 6 are arranged separately. One end of the rod 6 is fixed to the middle position of the short plate 5, and a recess 7 is provided on the outer side of one end of the rod 6. The recess 7 cooperates with the inner side wall of the through hole on the grid plate 1; the pin 4 is embedded in the through hole on the grid plate 1. Since the rods 6 are arranged separately, the two rods 6 are each inserted into a through hole. When the short plate 5 is attached to the grid plate 1, the side wall of the through hole on the grid plate 1 is embedded in the recess 7, clamping the rod 6 and stabilizing it, thereby improving the stability between the pin 4 and the grid plate 1, and the sharp parts on both sides of the short plate are also inserted into the through holes on the grid plate 1. After that, concrete is sprayed to cover the pin 4 on the grid plate 1, further improving the stability between the pin 4 and the grid plate 1.

[0078] Reference Figure 8 , a column-shaped hollow portion is opened inside the rod body 6, and a plurality of overflow holes 8 are opened on the outer wall of the rod body 6. The overflow holes 8 are connected to the hollow portion. A column-shaped aluminum foil bag body 9 is provided in the hollow portion. The bag body contains glue. A pull rope 10 is fixed to the aluminum foil bag body 9. The pull rope 10 is fixed to the part of the aluminum foil bag body 9 away from the recess 7. The other end of the pull rope 10 passes through the inner side of the recess 7 to open a slide groove 11. A slider 12 is provided at the notch of the slide groove 11. The slider 12 is slidably clamped in the notch of the slide groove 11 and fixed to the other end of the pull rope 10; after the pin 4 is inserted into the inner wall of the shaft, the through-hole side wall on the grid plate 1 Squeeze the slider 12 and squeeze it toward the short plate 5. At the same time, the slider 12 pulls the aluminum foil bag 9 through the pull rope 10, and the aluminum foil bag 9 is torn open. At this time, the glue in the aluminum foil bag 9 overflows. The glue is the same as the glue in the chemical expansion screw. The glue is discharged along the overflow hole 8 and flows on the outer ring of the rod body 6, bonding the rod body 6 to the inner side wall of the shaft to improve its stability. At the same time, part of the glue flows along the hollow part of the rod body 6 into the slide groove 11, bonding and fixing the slider 12, and bonding it to the inner side wall of the through hole, further improving the connection strength between the pin 4 and the grid plate 1.

[0079] Reference Figure 9 , a baffle 13 is provided in each through hole of the grid plate 1, and the lower end of the baffle 13 is vertically fixed to the inner bottom surface of the through hole, and is arranged close to the inner concave surface of the grid plate 1, and a gap is left between the upper end of the baffle 13 and the inner top surface of the through hole; the inner bottom surface of the through hole on the grid plate 1 is horizontal, and after the concrete is sprayed, it is difficult for the concrete to stay in the through hole, and multiple sprayings of concrete are required; for this reason, a baffle 13 is provided in the through hole of the grid plate 1, and after the concrete is sprayed on the grid plate 1, the concrete enters the through hole along the gap between the upper end of the baffle 13 and the inner top surface of the through hole, and then the concrete stays in the through hole and solidifies on the inner side wall of the shaft, forming horizontal concrete support rods the size of the through hole, which support the grid plate 1 on the side wall of the shaft to improve the stability of the grid plate 1.

[0080] Reference Figure 6 and Figure 9 The grid plate 1 is evenly provided with a plurality of insertion holes 14, and the insertion holes 14 are inclined downward, and the inclination direction is inclined from the concave surface of the grid plate 1 to the outer wall of the grid plate 1. The pins 4 are inserted into the insertion holes 14, and the short plates 5 on the pins 4 are provided with inclined surfaces, which are adapted to the concave surface of the grid plate 1; the insertion holes 14 are provided on the grid plate 1, and the inclined setting of the insertion holes 14 enables the pins 4 to be inserted into the insertion holes 14 in an inclined state, thereby improving the firmness of the grid plate 1, and the short plates 5 are provided with inclined surfaces, the rod body 6 is inserted into the inner wall of the shaft, and the inclined surface of the end plate is attached to the concave surface of the grid plate 1, thereby increasing the attachment surface between the pins 4 and the grid plate 1 and improving stability.

[0081] Reference Figure 10 The hook 3 is inserted into the upper grid plate 1 and then the rotating rod 15 is rotated, and the rotating rod 15 pulls the buckle 17, which approaches the outer surface of the grid plate 1 and is squeezed on the outer surface of the grid plate 1, thereby enhancing the stability between the hook 3 and the upper grid plate 1, thereby improving the stability between the upper and lower grid plates 1.

[0082] Example 2:

[0083] Reference Figure 11 , compared with Example 1, as another embodiment of the present invention, the upper edge of the grid plate 1 is set to be convex, and the lower edge of the grid plate 1 is set to be concave; the screw 21 is rotated, and the lower grid plate 1 moves upward. At this time, the convex part of the upper edge of the lower grid plate 1 is embedded in the concave position of the lower edge of the upper grid plate 1, constraining the positions of the upper and lower grid plates 1 to prevent the upper and lower grid plates 1 from being misaligned, resulting in an uneven inner surface of the grid component, affecting the lowering and removal of materials in the shaft.

[0084] Working principle: The underground excavation method does not dig up the ground, but adopts the method of digging holes underground for construction. The mining method and the shield method are both underground excavation methods. Due to the uncertainty of the engineering hydrogeological conditions and the complexity of the construction environment, there are still many construction risks in the construction process of shallow buried underground excavation underground engineering, and many risk accidents have occurred. Therefore, before excavation, it is necessary to carefully design the excavation technology and sequence; the construction technology of the subway underground excavation station project provided in the present invention has been studied in the early stage through technical investigation, theoretical analysis and numerical simulation, advanced geological prediction, field experiment and field test, induction and summary, technical refinement and other research methods, as well as drawing on a large number of foreign technologies, and also investigating and fully mastering The current status of research and application of similar projects and technologies at home and abroad was grasped, and the causes of excavation accidents were analyzed. Based on various investigations and analyses, a detailed research outline and work plan were formulated. Theoretical analysis and numerical simulation methods were then used to study the stress redistribution and displacement distribution laws of the surrounding rock during the pilot tunnel excavation process, as well as the stress characteristics of the support structure; the stress redistribution superposition law and the distribution of the plastic zone of the surrounding rock under the group tunnel effect were explored; the effects of different construction steps and intermediate rock column reinforcement schemes were compared; the construction methods and construction schemes were optimized; so that the construction technology of the subway underground excavation station project in the present invention can be carried out quickly and safely, and the completion time and quality are guaranteed;

[0085] In the early stage of station excavation, a vertical shaft is first excavated. The role of the vertical shaft here is to increase the working surface or set up a parallel guide pit to facilitate the construction. During the excavation of the vertical shaft, the inner wall of the vertical shaft needs to be protected to prevent the loose soil from causing a landslide accident, and secondly, to prevent the side wall undercurrent from flowing into the vertical shaft and causing an internal flooding accident. At present, the vertical shaft is constructed by the inverted shaft wall method, which is excavated and supported from top to bottom. The grid plate 1 is hoisted into the vertical shaft by hoisting equipment and then fixed on the inner wall of the vertical shaft. When the grid plate 1 is fixed, it is difficult to align the upper and lower grid plates 1, resulting in a large gap between the upper and lower grid plates 1. When spraying concrete, the concrete is difficult to adhere, resulting in weak concrete spraying at the gap, and the upper and lower grid plates 1 are separated. In the later stage, the concrete is sprayed and solidified, which is relatively fragile. In the process of lowering the construction materials into the vertical shaft in the later stage, they collide with the grid plate 1. The grid panels 1 are easy to loosen and detach; to address the above problem, the present invention cooperates with the screw rod 21 and the hook 3. After the upper grid panel 1 is fixed on the side wall of the shaft, when installing the lower grid panel 1, the lower grid panel 1 is preliminarily placed close to the upper grid panel 1, and then the No. 1 plate 2 on the lower grid panel 1 is rotated onto the upper grid panel 1, and then the hook 3 is inserted into the upper grid panel 1, and then the screw rod 21 is rotated. The screw 21 pulls the lower grid panel 1 upward, so that the upper and lower grid panels 1 are close to each other and attached together, reducing the gap between the upper and lower grid panels 1, and then the nail 4 is inserted into the through hole on the grid panel 1, and the nail 4 is knocked into the inner wall of the shaft; the close attachment between the upper and lower grid panels 1 improves the spraying and adhesion effect of concrete, contributes to the stable installation of the grid component, and enhances the performance of the grid component in resisting external collision forces;

[0086] The pins 4 are embedded in the through-holes on the grid plate 1. Since the rods 6 are arranged separately, the two rods 6 are each inserted into a through-hole. When the short plate 5 is attached to the grid plate 1, the side walls of the through-hole on the grid plate 1 are embedded in the recess 7, clamping the rods 6 and stabilizing them, improving the stability between the pins 4 and the grid plate 1. The sharp parts on both sides of the short plate are also inserted into the through-holes on the grid plate 1. After that, concrete is sprayed to cover the pins 4 on the grid plate 1, further improving the stability between the pins 4 and the grid plate 1.

[0087] After the pin 4 is inserted into the inner wall of the shaft, the side wall of the through hole on the grid plate 1 squeezes the slider 12, squeezing the slider 12 toward the short plate 5. At the same time, the slider 12 pulls the aluminum foil bag 9 through the pull rope 10, and the aluminum foil bag 9 is torn open. At this time, the glue in the aluminum foil bag 9 overflows. This glue is the same as the glue in the chemical expansion screw. The glue is discharged along the overflow hole 8 and flows on the outer ring of the rod body 6, bonding the rod body 6 to the inside of the inner wall of the shaft, improving its stability. At the same time, part of the glue flows along the hollow part of the rod body 6 into the chute 11, bonding and fixing the slider 12, and bonding it to the inner wall of the through hole, further improving the connection strength between the pin 4 and the grid plate 1;

[0088] The bottom surface of the through hole on the grid plate 1 is horizontal. After the concrete is sprayed, it is difficult for the concrete to stay in the through hole, and multiple sprayings of concrete are required. For this reason, a baffle 13 is provided in the through hole of the grid plate 1. After the concrete is sprayed on the grid plate 1, the concrete enters the through hole along the gap between the upper end of the baffle 13 and the inner top surface of the through hole. The concrete then stays in the through hole and solidifies on the inner wall of the shaft, forming horizontal concrete support rods the size of the through hole, which support the grid plate 1 on the side wall of the shaft, thereby improving the stability of the grid plate 1.

[0089] The grid plate 1 is provided with a socket 14, and the socket 14 is arranged at an angle, so that the pin 4 is inserted into the socket 14 in an inclined state, thereby improving the firmness of the grid plate 1. The short plate 5 is provided with an inclined surface, and the rod body 6 is inserted into the inner wall of the shaft. The inclined surface of the end plate is attached to the inner concave surface of the grid plate 1, thereby increasing the attachment surface between the pin 4 and the grid plate 1 and improving stability.

[0090] The hook 3 is inserted into the upper grid plate 1, and then the rotating rod 15 is rotated. The rotating rod 15 pulls the buckle 17, and the buckle 17 approaches the outer surface of the grid plate 1 and is squeezed on the outer surface of the grid plate 1, thereby enhancing the stability between the hook 3 and the upper grid plate 1, thereby improving the stability between the upper and lower grid plates 1; the screw 21 is rotated, and the lower grid plate 1 moves upward. At this time, the raised part of the upper edge of the lower grid plate 1 is embedded in the concave position of the lower edge of the upper grid plate 1, constraining the position of the upper and lower grid plates 1 to prevent the upper and lower grid plates 1 from being misaligned, resulting in an uneven inner surface of the grid component, which affects the lowering and removal of materials in the shaft.

[0091] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0092] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for a subway underground excavation station project, characterized by: The invention comprises an earth excavation construction method, and the earth excavation construction method comprises the following steps: Step 1: Set up a water-stop curtain at the location of the shaft to be excavated. After the construction of the water-stop curtain is completed, conduct temporary shaft excavation. When the shaft is excavated to a position 0.5m above the water level, conduct temporary bottom sealing. After the cross-passage horse head gate is reinforced, excavate the first and second-level cross passages. Step 2: After the end of the cross passage is sealed and the advance support of the small pilot tunnel is completed, the upper pilot tunnels on both sides and the middle upper pilot tunnel are excavated; Step 3: Excavate the middle and upper pilot tunnels, seal the ends, and then install mechanical retaining piles, pile top crown beams, and side arch primary support backfill in the upper pilot tunnel; Step 4: Carry out water-stop curtain in the second-floor transverse passage. After the water-stop curtain is formed, excavate the temporary construction shaft to the permanent bottom, and excavate the third, fourth, fifth and sixth-floor transverse passages; Step 5: After the transverse passage is sealed, a deep hole grouting water-stop curtain with full section of the lower pilot tunnel is constructed in the transverse passages on the fifth and sixth floors. After the water-stop curtain is formed, the pilot tunnel gate is reinforced and the lower side pilot tunnel is excavated. Step 6: After the lower side pilot tunnel is constructed for 12-15m, the lower middle pilot tunnel is excavated. After the pilot tunnel ends are sealed, the bottom longitudinal beam is constructed in the lower pilot tunnel; Step 7: After the bottom longitudinal beam is constructed, the middle column hole and the segment column hole are manually excavated in the upper pilot hole. After the middle column hole and the segment column hole are constructed, the steel pipe column and the steel cage inside the column are installed. After the concrete of the steel pipe column is poured, the column top longitudinal beam is constructed; Step 8: After the large arch pipe shed is completed in the transverse passage construction, the top longitudinal beam is completed, and after the initial support and arch door reinforcement of the transverse passage construction is completed, the AB span and CD span arch excavation is carried out; Step 9: After the AB and CD spans have been excavated for 15m, the BC and DE spans will be excavated. After the primary support arch construction is completed, the secondary lining arch crown construction will be carried out; Step 10: After the construction of the second lining arch is completed, the station hall layer is excavated downward in layers, and the station hall layer inter-pile sprayed anchor support and the middle plate, longitudinal beam, track top air duct and side wall structure are constructed; Step 11: After the station hall structure reaches the design strength, excavate the platform layer downwards and construct the platform layer inter-pile sprayed anchor support and bottom plate and side wall structures.

2. The construction method of a subway underground excavation station project according to claim 1, characterized in that: For the temporary shaft excavation work described in step 1, the shaft body is constructed using the inverted shaft wall method, and support is provided while excavating from top to bottom. The excavation method is half-width sequential excavation. First, excavate part ①, excavate earth, erect grid frames, and spray concrete. Then, excavate part ②, excavate earth, erect grid frames, and spray concrete to form a ring. The shaft excavation size is 6.2*7.6m, and the excavation step distance is 0.5m per grid frame.

3. The construction method of a subway underground excavation station project according to claim 1, characterized in that: For the primary buckle arch door in step 8, only the primary buckle arch and primary support grid structure between the main pilot tunnels are erected, and there is no need to close the lower arch to form a ring. Therefore, the upper steps of the primary buckle arch are manually excavated and the initial support structure is constructed using low steps, and the lower steps are mechanically excavated; The excavation parameters for the initial support arch guide tunnel are: a. Mechanical earthwork is used for the lower steps. To prevent impact on the upper steps, the upper steps are initially reserved at a length of 5-8m. Based on the actual situation at the construction site, the lower steps will be excavated after the upper steps are completed. b. The height between the upper step interface and the primary support arch is 1.5-1.7m, which is convenient for construction workers to carry out earth excavation and initial support construction; c. The core package for the upper steps is reserved. The size of the core package for the middle span is 0.75m high and 2.7m wide; the size of the core package for the side span is 0.75m high and 3.6m wide; d. When constructing the upper steps, reserve core soil with a height of no less than 0.3m and a length of no less than 1.7m; e. The lower step is 2.65m high and is excavated by a small excavator. The excavated soil is directly loaded onto a tricycle for transport; f. A 1.2m height earthwork is reserved at the bottom without construction, providing a foundation for the secondary lining structure construction trolley in the later stage.

4. The construction method of a subway underground excavation station project according to claim 3 is characterized by: The grid frame comprises a plurality of arc-shaped grid plates (1); a base block is symmetrically fixed to the inner concave surface of the upper end of the grid plate (1); a No. 1 plate (2) is connected to the base block, and the base block is rotatably connected to one end of the No. 1 plate (2); the other end of the No. 1 plate (2) is threadedly connected to one end of a screw rod (21); the other end of the screw rod (21) is rotatably connected to a hook (3); the angle at the corner position of the hook (3) is 60-80 degrees; each grid plate (1) is provided with a pin (4); the pin (4) is T-shaped, and the long end of the pin (4) passes through the upper through hole of the grid plate (1) and is embedded in the side wall of the shaft.

5. The construction method of a subway underground excavation station project according to claim 4, characterized in that: The inserting pin (4) comprises a short plate (5) and two rod bodies (6), the rod bodies (6) are arranged separately, one end of the rod body (6) is fixedly connected to the middle position of the short plate (5), and a recess (7) is provided on the outer side of one end of the rod body (6), and the recess (7) is matched with the inner side wall of the through hole on the grid plate (1).

6. The construction method of a subway underground excavation station project according to claim 5, characterized in that: A columnar hollow portion is provided inside the rod body (6), and a plurality of overflow holes (8) are provided on the outer wall of the rod body (6). The overflow holes (8) are communicated with the hollow portion. A columnar aluminum foil bag body (9) is provided inside the hollow portion. The bag body contains glue. A drawstring (10) is fixed to the aluminum foil bag body (9). The drawstring (10) is fixed to a portion of the aluminum foil bag body (9) away from the recess (7). The other end of the drawstring (10) passes through a slide groove (11) provided inside the recess (7). A slider (12) is provided at the notch of the slide groove (11). The slider (12) is slidably clamped in the notch of the slide groove (11) and is fixed to the other end of the drawstring (10).

7. The construction method of a subway underground excavation station project according to claim 4, characterized in that: A baffle (13) is provided in each through hole of the grid plate (1), the lower end of the baffle (13) is vertically fixed to the inner bottom surface of the through hole, is arranged close to the inner concave surface of the grid plate (1), and a gap is left between the upper end of the baffle (13) and the inner top surface of the through hole.

8. The construction method of a subway underground excavation station project according to claim 7, characterized in that: The grid plate (1) is evenly provided with a plurality of insertion holes (14), the insertion holes (14) are arranged to be tilted downward, and the tilting direction is tilted from the inner concave surface of the grid plate (1) to the outer wall of the grid plate (1), the insertion nail (4) is inserted into the insertion hole (14), and the short plate (5) on the insertion nail (4) is provided with an inclined surface, and the inclined surface is adapted to the inner concave surface of the grid plate (1).

9. The construction method of a subway underground excavation station project according to claim 4, characterized in that: A rotating hole is provided on the back side of the corner of the hook (3), and the rotating hole is provided along the end direction of the hook (3). A rotating rod (15) is provided in the rotating hole. A guide groove (16) is provided on the inclined bottom surface of the hook (3). The guide groove (16) is provided with a buckle (17). One end of the buckle (17) is threadedly connected to the rotating rod (15), and the other end of the buckle (17) is tilted and points toward the vertical rod part of the hook (3).

10. The construction method of a subway underground excavation station project according to claim 8, characterized in that: The upper edge of the grid plate (1) is arranged in a convex manner, and the lower edge of the grid plate (1) is arranged in a concave manner.

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