Tunnel portal wall stone facing structure and construction method

Abstract

The invention discloses a tunnel portal wall stone facing structure and a construction method, comprising a wall surface, an arch ring, a square facing, a strip facing, an arc facing and an anchor bolt, etc. The advantages of the structure are as follows: first, the structural safety is ensured by comprehensively considering the complex stress conditions of the traffic tunnel portal wall; second, according to the stress characteristics of the stone facing, the anchor bolt and the wall surface are formed into a certain angle to optimize the structural stress, and the anchor bolt hole is tilted upward to pour mortar, which saves materials and fills densely; third, the connecting parts are cheap and have strong overall stability, a seepage pipe is added between the stone facing and the tunnel portal wall for drainage, and the gap is filled with self-compacting concrete mixed with inorganic fibers such as polypropylene fibers, so as to improve crack resistance and durability; fourth, the calculation method has a clear principle, is practical and easy to implement, and improves safety and quality performance, so the structure has the advantages of simple structure, convenient construction, safety and reliability, beautiful and practical, resource saving, etc., combined with the corresponding construction method, the economic and social benefits are remarkable.

Description

Technical Field

[0001] The invention relates to the field of tunnel construction, and in particular to a tunnel portal wall stone facing structure and a construction method. Background Art

[0002] Dry hanging stone materials are widely used in building exterior walls. Some traffic tunnel projects have tried to directly transplant them to tunnel portal wall stone facings, but due to certain safety hazards, no substantial progress has been made. The main reason is that traffic tunnels are different from construction projects. The stress conditions of traffic tunnel portal walls are very complicated. There are not only climate and environmental influences such as seepage water, ice and snow, and natural wind, but also external forces such as driving vibration and vehicle piston wind force. Therefore, the stone facing structure of the tunnel portal wall needs to comprehensively consider the above factors to ensure the safety of project operation and smooth traffic. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a tunnel portal wall stone facing structure and construction method which is simple in structure, convenient in construction, safe and reliable, beautiful and practical, and resource-saving.

[0004] The technical problem of the present invention is achieved through the following technical solutions:

[0005] A tunnel portal wall stone facing structure, comprising a wall and an arch ring constituting the tunnel portal wall, and a plurality of square facings, a plurality of strip facings and a plurality of arc facings constituting the stone facing, wherein the plurality of square facings are flatly laid on the wall, a face groove and a 7-shaped plate insert embedded in the face groove are provided in the middle of the back of each square facing, a side groove is provided on the upper edge surface and the lower edge surface of each square facing, a T-shaped plate insert is provided between the side grooves of each two adjacent square facings, and the 7-shaped plate insert and the T-shaped plate insert are both connected to the tunnel portal wall and are tiltedly anchored via a connecting piece. The plurality of strip facings are horizontally laid on the top of the wall, and each strip facing is bonded and connected to the adjacent square facings; the plurality of arc facings are laid along the outer edge of the arch ring, and the middle part of the back of each arc facing is provided with a surface groove and a 7-shaped plate insert embedded in the surface groove, and the 7-shaped plate insert is connected to the anchor bolts obliquely anchored on the tunnel portal wall through a connecting piece; a plurality of seepage pipes arranged in the longitudinal and transverse directions and poured self-compacting concrete are provided between the stone facing and the tunnel portal wall, and each two adjacent stone facings are sealed and glued.

[0006] The diameter of each anchor bolt is , with the horizontal plane The corners are anchored on the tunnel portal wall, and the total length of each anchor is , terminal The length is threaded and anchored to the connector through nuts and wedge-shaped pads. The anchor bolt and the connector are elastically embedded. The anchor bolt is anchored in the anchor bolt hole on the wall of the tunnel portal for an anchor length of The anchor holes are bonded with cement mortar. The anchors are subjected to the external forces of self-compacting concrete, stone facing, connection parts, ice and snow, natural wind, driving vibration, and vehicle piston wind. Each anchor is subjected to the force of an elastic foundation beam with one end elastically embedded and one end free. , free end The tensile elastic coefficient and compressive elastic coefficient of cement mortar are The comprehensive elastic coefficient is equal to the sum of the tension elastic coefficient and the pressure elastic coefficient. The comprehensive elastic reaction force is According to the elastic foundation beam mechanics theory, the anchor bolt force is calculated as follows:

[0007] Formula 1:

[0008]

[0009] From the above formula, we can get

[0010] From the above equations, we can find ;

[0011] Formula 2:

[0012]

[0013] The symbols in Formula 1 and Formula 2 are defined as:

[0014] ——The force reserved by the anchor bolt on the tunnel portal wall The horizontal calculated length of the action point, ;

[0015] ——Anchor bolt Length of anchoring on the tunnel portal wall, ;

[0016] - diameter of the anchor bolt, ;

[0017] - diameter of the anchor hole, ;

[0018] - Angle between the anchor bolt and the horizontal line, ;

[0019] ——Based on the center of the anchor bolt on the tunnel portal wall Point is the coordinate value of the origin along the length of the anchor bolt. ;

[0020] ——Based on the center of the anchor bolt on the tunnel portal wall The point is the origin and perpendicular to the anchor bolt The deformation curve equation of the length is the anchor bolt The deformation value at ;

[0021] ——Anchor bolt The absolute value of the maximum deformation at ;

[0022] ——Respectively, they are the comprehensive elastic coefficient, tension elastic coefficient and pressure elastic coefficient of cement mortar, which are determined through tests. In the absence of test data, they are determined according to relevant specifications. ;

[0023] ——Comprehensive elastic reaction force , ;

[0024] - bending stiffness of anchor bolts, ;

[0025] ——The horizontal calculated length of the anchor bolt from the tunnel portal wall surface The load of a single anchor bolt at the outer end A includes the self-compacting concrete, stone facing, the self-weight of the connector, ice and snow, natural wind, driving vibration, and external forces of vehicle piston wind. , ;

[0026] ——The load acting on a single anchor bolt includes the self-compacting concrete, stone facing, the self-weight of the connector, and the conventional total load of ice, snow, and natural wind. ;

[0027] ——Vehicle piston wind load. When a vehicle drives to the tunnel entrance, due to the space limitation of the tunnel wall, the air pushed by the vehicle cannot all flow around to the rear of the vehicle. Some air will inevitably be pushed forward by the vehicle, and there is a negative pressure area behind the rear end of the vehicle. This is called the "piston effect". At this time, the tunnel portal wall generates a vehicle piston wind pull load into the tunnel portal. The vehicle piston wind load is related to many factors such as the vehicle speed, the number of vehicles, the tunnel entrance environment, and the friction resistance of the inner wall of the tunnel. The vehicle piston wind load acting on a single anchor bolt is The force is obtained by testing. ;

[0028] ——The driving vibration coefficient acting on a single anchor bolt shall be determined through tests. In the absence of test data, it shall be determined by referring to relevant specifications, or it may be taken as 1.05 to 1.45 for a stable driving state of the vehicle depending on the smoothness of the road surface at the tunnel entrance;

[0029] ——Anchor bolts Bending moment, shear force and rotation at ;

[0030] ——Action on anchor bolts Moment and shear force at the end, ;

[0031] ——Action on anchor bolts B Moment and shear force at the end, ;

[0032] --coefficient, , ;

[0033] ——Deformation coefficient of anchor bolt calculated as elastic foundation beam;

[0034] ——are the allowable bending moment and allowable shear strength of the anchor bolt, ;

[0035] ——are the allowable tensile strength and allowable compressive strength of cement mortar, .

[0036] The connecting parts include inner angle steel connecting parts and outer angle steel connecting parts; the T-shaped plate insert is connected to the anchor bolts obliquely anchored on the tunnel portal wall via the outer angle steel connecting parts; the 7-shaped plate insert is connected to the anchor bolts obliquely anchored on the tunnel portal wall via the inner angle steel connecting parts; a cross plate connected to each other is provided between the inner angle steel connecting parts and the outer angle steel connecting parts.

[0037] A lightning rod is buried on the top of the tunnel portal wall. The lightning rod is connected to all connectors via a conductor and then connected to a grounding wire.

[0038] The seepage pipe is durable ASAThe modified resin pipe has an outer diameter of 1.5cm-2.0cm and a wall thickness of 1.5mm-2.0mm. The seepage pipe is covered with a double-layer geotextile and arranged at intervals of 50cm-100cm in the longitudinal and transverse directions along the wall of the tunnel portal. The connections between the seepage pipes are sealed with resin glue. The longitudinal seepage pipe is perforated with plum blossom-shaped holes every 50cm-100cm to penetrate the entire section, and the upward part of the transverse seepage pipe is perforated with plum blossom-shaped semicircles every 50cm-100cm. The seepage pipe is tied to the connecting piece, and the lowest end interface of the seepage pipe is connected to the longitudinal drainage ditch of the tunnel.

[0039] Each of the square facings is 110cm to 120cm long, 50cm to 60cm wide, and 2.8cm to 3.2cm thick; each of the arc facings is 80cm to 120cm long, with a width equal to the width of the arch ring and a thickness of 2.8cm to 3.2cm; each of the strip facings is 110cm to 120cm long, 20cm to 30cm wide, and 8cm to 10cm thick; a side groove is cut in the middle of the upper edge and the lower edge of the square facing, the size of the side groove is not less than 20mm high × 0.8mm wide, and is fixed by a T-shaped plate insert, and the gap between the side groove and the T-shaped plate insert is 1.5mm to 2.0mm; a plurality of surface grooves are cut in the middle of the back of the square facing, and each surface groove is The dimensions are not less than 120mm high × 20mm wide, each surface groove is embedded with a 7-shaped plate insert, and the gap between the surface groove and the 7-shaped plate insert is 1.5mm~2.0mm; a plurality of surface grooves are cut in the middle of the back of the arc-shaped decorative surface, and the dimensions of each surface groove are not less than 120mm high × 20mm wide, each surface groove is embedded with a 7-shaped plate insert, and the gap between the surface groove and the 7-shaped plate insert is 1.5mm~2.0mm; the strip decorative surface is bonded to the top of the wall of the tunnel portal wall by cement mortar, and the plane formed by the square decorative surface and the arc-shaped decorative surface is suspended for 5cm~8cm; a separation seam is provided between the two adjacent stone decorative surfaces, and the separation seam is filled with foam strips and silicone structural sealant for sealing.

[0040] The size of the outer angle steel connector is not less than ∟50mm×5mm, and the length is the same as the length of the square decorative surface; the size of the inner angle steel connector is not less than ∟50mm×5mm×120mm.

[0041] The anchor bolt is of length A steel bar with a threaded end and a diameter of In the anchor holes, multiple anchor holes are aligned with the horizontal plane. Drill holes in the tunnel door wall. The gaps between the multiple anchor holes and the anchors are bonded by high-strength cement mortar, and the nuts are anchored with the wedge-shaped pads and the connectors connecting the multiple anchors, and the connectors are then connected with the T-shaped plate inserts or the 7-shaped plate inserts by bolts; the wedge-shaped pads have a wedge-shaped inclination angle of The plane arrangement of the plurality of anchor bolts is adjusted accordingly with respect to the different positions of the arch rings in terms of their spacing and plane positions.

[0042] The self-compacting concrete is a self-compacting fiber concrete, which is a high-performance cement concrete that can be compacted under its own gravity without any vibration; polypropylene fiber-like inorganic fibers are added to the self-compacting concrete and filled into the gaps between the stone facing and the surface of the tunnel portal wall, as well as between the connectors and the seepage pipes; the minimum layer thickness of the self-compacting concrete is not less than 2 cm, and the diameter of the coarse aggregate constituting the self-compacting concrete is not more than 1.0 cm.

[0043] A tunnel portal wall stone facing structure construction method comprises the following steps:

[0044] Step 1: Investigation, testing and design calculation

[0045] Preliminary design of the structural scheme of stone facing according to the construction scale of the tunnel portal wall, and put forward the technical requirements and standards of the materials used;

[0046] Determined by test, or in the absence of test data, the comprehensive elastic coefficient, tension elastic coefficient and pressure elastic coefficient of cement mortar are determined according to relevant specifications ;

[0047] Through investigation and calculation of the loads acting on a single anchor bolt, including the self-compacting concrete, stone facing, the self-weight of the connector, and the conventional total load of ice, snow, and natural wind;

[0048] By testing and calculating the wind load of the vehicle piston acting on a single anchor bolt;

[0049] Determined by test, or in the absence of test data, determined by referring to relevant specifications or selecting the driving vibration coefficient for the vehicle's stable driving state based on the smoothness of the road surface at the tunnel entrance;

[0050] Calculate the anchor bolt length, specification size and material requirements by formula 1 and formula 2;

[0051] Design detailed construction drawings, determine raw materials, construction technical requirements and standards;

[0052] Step 2: Make the structural components of the stone veneer

[0053] Check whether the dimensions of the tunnel portal wall are consistent with the design drawings;

[0054] ② Make seepage pipes and connectors according to the design drawings, with the quantity and quality meeting the design requirements;

[0055] Select the appearance, color and texture of the stone facing according to the design drawings, and cut the external dimensions, grooves, quantity and specifications to meet the design requirements;

[0056] Step 3: Set up construction scaffolding

[0057] Build construction scaffolding along the tunnel portal wall, and the reserved width between the scaffolding and the tunnel portal wall should be convenient for construction operations;

[0058] ② Clean the concrete residue and cement slurry on the tunnel portal wall, and roughen the concrete where it is too smooth;

[0059] Mark out the stone facing blocks according to the design drawings, and mark the anchor bolt position marks and seepage pipe position marks;

[0060] Step 4: Install the seepage pipe

[0061] Install longitudinal seepage pipes and transverse seepage pipes from top to bottom, and fix the seepage pipes with cement nails and iron wires;

[0062] ② The joints of the longitudinal seepage pipe and the transverse seepage pipe are sealed with silicone structural sealant;

[0063] The lowest interface of the seepage pipe is connected to the longitudinal drainage ditch of the tunnel;

[0064] Step 5: Stone facing construction

[0065] Determine the raw materials and mix ratios of cement mortar, self-compacting concrete and silicone structural sealant through experiments;

[0066] ② Drill anchor holes. The hole diameter and depth of the anchor holes meet the design requirements. After drilling, use an air compressor to clean the holes;

[0067] Mix cement mortar, pour mortar into the first hole and test-insert anchor bolts to determine the amount of mortar to avoid excessive waste; pour cement mortar into the anchor bolt hole, rotate the anchor bolt back and forth to the bottom until the hole overflows with mortar, and hang the geotextile externally to sprinkle water for the specified time;

[0068] Install the connectors of the first row of square facings and the first curved facing at the bottom, install the first row of square facings and the first curved facing at the bottom, and adjust the plane position of the square facings accurately; reserve a separation gap on the side of the first row of square facings and the side of the first curved facing at the bottom, fill the separation gap with foam strips, and fill the outside of the foam strips with silicone structural sealant for sealing;

[0069] After the silicone structural sealant is cured, pour the mixed self-compacting concrete into the gap between the first row of square facings, the first curved facing and the tunnel portal wall. Use a wooden hammer to gently tap the first row of square facings and the first curved facing underneath. After the self-compacting concrete is poured densely, clean the concrete slurry in the top side groove of the first row of square facings underneath, and cover with geotextile for maintenance.

[0070] Follow this step , Install the upper row and the rows above the square facings. If the height of the upper row or the rows above the upper row is higher than the first curved facing below, continue to install the second curved facing at the same time, so that the curved facing at the arch ring is installed synchronously with the square facing. The upper and lower rows, the periphery of the same row, and the separation seams with the curved facings are filled with foam strips and silicone structural sealant for sealing. After the silicone structural sealant is cured, pour the self-compacting concrete. The arch ring is installed symmetrically. After the square facings are installed, mortar is laid on the top of the highest row of square facings, and the strip facings are installed;

[0071] Step 6: Install lightning protection device

[0072] Bury the ground wire in front of the bottom first row of square facings and the bottom first curved facing;

[0073] ②After the anchor bolts and connectors are installed, use wires to connect all connectors and access the grounding wire, and reserve a connecting wire from the highest row of connectors to the top lightning rod;

[0074] Lay cement mortar on the top of the highest row of square facings and embed the top lightning rod before installing the strip facings;

[0075] Step 7: Stone surface maintenance and quality inspection

[0076] During the process of pouring cement mortar into anchor bolts and completing all stone facing construction, we pay attention to the quality of project construction, carry out necessary tests and inspections, and carry out timely maintenance to ensure the internal quality. The width of the dividing joints is consistent, the dividing lines of the stone facings are straight, the vertical dividing joints are staggered to leave no vertical seams, and the appearance is smooth and beautiful.

[0077] Compared with the prior art, the present invention mainly provides a tunnel portal wall stone facing structure, which has the following advantages: first, in view of the different characteristics of traffic tunnels and construction projects, the complex stress conditions of the traffic tunnel portal wall are comprehensively considered, taking into account the influence of climate environment such as seepage water, ice and snow, natural wind, and external force loads such as driving vibration and vehicle piston wind force to ensure safety; second, according to the stress characteristics of the tunnel portal wall stone facing, the anchor bolts are set to form a certain angle with the wall surface, the structural stress is optimized, the vertical stress of the stone facing part is converted into the pressure of the anchor bolts, and when the anchor bolt holes are tilted upward to pour mortar, compared with the conventional horizontal anchor bolt holes, sand is avoided. The slurry outflow is wasted, which not only saves materials but also facilitates the filling of mortar for compaction; thirdly, the connectors used are all ordinary steel, which saves costs compared to the conventional stainless steel connectors. Adjacent connectors are welded to each other with cross plates to enhance the overall stability. At the same time, vertical and horizontal seepage pipes are set between the stone facing and the surface of the tunnel portal wall for drainage. The gap is filled with self-compacting concrete mixed with polypropylene fiber and inorganic fiber. The advantages of wet pasting method and dry hanging method of stone facing are combined to improve the crack resistance and durability; fourthly, the calculation method provided has clear principles, is practical and easy to use, and can be used as a guide for the design and construction of tunnel portal wall stone facing structures, improving safety and quality performance. Therefore, the present invention is a tunnel portal wall stone facing structure with simple structure, convenient construction, safety and reliability, beautiful and practical, and resource-saving. It can ensure the safety of engineering operation and smooth traffic. Combined with the corresponding construction method, it has higher economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a schematic diagram of the structural elevation of the present invention.

[0079] Figure 2 This is the structural elevation drawing of the stone facing of the tunnel portal wall.

[0080] Figure 3 for Figure 2 Ⅰ-Ⅰ and Ⅱ-Ⅱ cross-section diagrams.

[0081] Figure 4 for Figure 2 Ⅲ-Ⅲ cross-section diagram.

[0082] Figure 5 This is the force calculation diagram for anchor bolts. DETAILED DESCRIPTION

[0083] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0084] like Figure 1~Figure 5As shown, 1. Tunnel portal wall, 11. Arch ring, 12. Wall, 13. Lightning rod, 14. Grounding wire, 2. Seepage pipe, 21. Horizontal seepage pipe, 22. Longitudinal seepage pipe, 3. Stone facing, 31. Square facing, 32. Strip facing, 33. Arc facing, 34. Side groove, 35. Surface groove, 36. Dividing joint, 4. Anchor bolt, 41. Cement mortar, 42. Nut, 43. Wedge-shaped pad, 5. Connector, 511. External angle steel connector, 512. Internal angle steel connector, 52. T-plate insert, 53. 7-plate insert, 54. Cross plate, 55. Bolt, 6. Self-compacting concrete.

[0085] A tunnel portal wall stone facing structure and construction method, such as Figure 1~Figure 4 As shown, it relates to a field of tunnel construction, which mainly involves paving a plurality of stone facings 3 on a wall 12, an arch ring 11 and a wall top constituting a cement concrete tunnel portal wall. The tunnel portal wall 1 is a protective engineering structure of the tunnel portal, and can be used as a basis for setting the stone facings 3, connectors 5, anchor bolts 4 and self-compacting concrete 6, etc. The stone facings 3 are granite-like stones that are not easily weathered, and are in three styles, namely, a plurality of square facings 31, a plurality of strip facings 32 and a plurality of arc facings 33.

[0086] The multiple square facings 31 are laid flat on the wall 12, and each of the square facings 31 has a length of 110cm to 120cm, a width of 50cm to 60cm, and a thickness of 2.8cm to 3.2cm. A surface groove 35 and a 7-shaped plate insert embedded in the surface groove are provided in the middle of the back side of each square facing 31. A side groove 34 is provided on the upper edge surface and the lower edge surface of each square facing 31. A T-shaped plate insert is provided between the side grooves of each adjacent two square facings 31, and the 7-shaped plate insert and the T-shaped plate insert are connected to the anchor bolt 4 obliquely anchored on the tunnel portal wall 1 through the connecting piece 5.

[0087] The plurality of strip-shaped decorative surfaces 32 are horizontally laid on the top of the wall 12 . Each strip-shaped decorative surface 32 has a length of 110 cm to 120 cm, a width of 20 cm to 30 cm, and a thickness of 8 cm to 10 cm. Each strip-shaped decorative surface 32 is bonded and connected to the adjacent square decorative surface 31 .

[0088] The multiple arc-shaped decorative surfaces 33 are paved along the outer edge of the arch ring 11. Each of the arc-shaped decorative surfaces 33 is 80cm to 120cm long, has a width equal to the width of the arch ring, and a thickness of 2.8cm to 3.2cm. A surface groove 35 and a 7-shaped plate insert embedded in the surface groove are provided in the middle of the back side of each arc-shaped decorative surface 33. The 7-shaped plate insert is connected to the anchor bolt 4 obliquely anchored on the tunnel portal wall 1 through the connecting piece 5.

[0089] The connector 5 is mainly composed of an inner angle steel connector 512 and an outer angle steel connector 511, and the above components are all made of ordinary steel materials.

[0090] Moreover, the T-shaped plate insert 52 is connected to the anchor bolt 4 obliquely anchored on the tunnel portal wall 1 through the outer angle steel connector 511, the size of the outer angle steel connector 511 is not less than ∟50mm×5mm, and the length is the same as the length of the square facing 31; the 7-shaped plate insert 53 is connected to the anchor bolt 4 obliquely anchored on the tunnel portal wall 1 through the inner angle steel connector 512, the size of the inner angle steel connector 512 is not less than ∟50mm×5mm×120mm, and a cross plate 54 connected to each other is provided between the inner angle steel connector 512 and the outer angle steel connector 511 for reinforcement. The T-shaped plate insert 52 and the outer angle steel connector 511, and the 7-shaped plate insert 53 and the inner angle steel connector 512 are mainly connected and fixed by bolts 55.

[0091] The side groove 34 is cut through the middle of the upper and lower edge surfaces of the square decorative surface 31. The side groove 34 is a square groove with a size of not less than 20 mm in height × 0.8 mm in width. The two side grooves of the upper and lower adjacent square decorative surfaces 31, that is, the side groove on the lower edge surface of the upper square decorative surface and the side groove on the upper edge surface of the lower square decorative surface are jointly embedded by a T-shaped plate insert 52, and the gap between the side groove 34 and the T-shaped plate insert 52 is 1.5 mm to 2.0 mm.

[0092] The surface grooves 35 are cut in the middle of the back side of the square decorative surface 31 and the middle of the back side of the arc-shaped decorative surface 33. Each surface groove 35 is also a square groove with a size of not less than 120 mm in height × 20 mm in width. Each surface groove 35 is embedded with a 7-shaped plate insert 53, so the number of surface grooves is the same as the number of 7-shaped plate inserts. The gap between the surface groove 35 and the 7-shaped plate insert 53 is 1.5 mm to 2.0 mm.

[0093] The strip facing 32 is bonded to the top of the wall surface 12 of the tunnel portal wall 1 by cement mortar 41, and suspends 5cm to 8cm of the plane formed by the square facing 31 and the arc facing 33. The cement mortar 41 is high-strength cement mortar, and the raw materials and mix ratio are determined through experiments.

[0094] The multiple stone facings 3 are divided into blocks according to the size of the tunnel portal wall 1. The parts of the tunnel portal wall that need to be paved with square facings 31, strip facings 32 or arc facings 33 must be neat and tidy. A separation seam 36 of 0.8 cm to 1.2 cm is provided between two adjacent stone facings 3. For example, the separation seam can be provided between two adjacent square facings 31, strip facings 32 and arc facings 33, or between a square facing 31 and a strip facing 32, or between a square facing 31 and an arc facing 33. The vertical separation seams 36 are staggered with each other without leaving vertical through seams, and foam strips and silicone structural sealants are filled in the separation seams 36 facing the direction of the tunnel portal wall stone facing for sealing and gluing to fix the stone facing.

[0095] A plurality of seepage pipes 2 arranged in the longitudinal and transverse directions are provided between the stone facing 3 and the tunnel portal wall 1 to facilitate drainage of seepage water. After the silicone structural sealant is cured, self-compacting concrete is poured into the gap between the stone facing 3 and the tunnel portal wall 1 for connection reinforcement. The seepage pipes 2 are made of durable ASA The modified resin pipe has an outer diameter of 1.5cm to 2.0cm and a wall thickness of 1.5mm to 2.0mm. The seepage pipe 2 is wrapped with a double-layer geotextile and arranged at intervals of 50cm to 100cm in the longitudinal and transverse directions along the wall surface 12 of the tunnel portal, that is, a transverse seepage pipe 21 in the horizontal direction and a longitudinal seepage pipe 22 in the vertical direction. The connections between the longitudinal and transverse seepage pipes are sealed with resin glue. The longitudinal seepage pipe 22 is perforated in a plum blossom shape every 50cm to 100cm to penetrate the entire cross-section, and the upward part of the transverse seepage pipe 21 is perforated in a plum blossom shape every 50cm to 100cm to penetrate in a semicircular shape. All the seepage pipes 2 are tied to each connector 5 by steel wire, and the interface at the lowest end of the seepage pipe 2 is connected to the longitudinal drainage ditch of the tunnel.

[0096] The self-compacting concrete 6 is a self-compacting fiber concrete, which is a high-performance cement concrete that can be compacted and formed without any vibration under its own gravity. The strength grade of the self-compacting concrete meets the requirements of the mix design strength grade mainly by controlling the cement strength and water-cement ratio, age, and curing conditions, and other properties such as elastic modulus, high crack resistance, long-term performance, and durability meet the design or relevant standards. Inorganic fibers such as polypropylene fibers are added to the self-compacting concrete to enhance crack resistance, and fill in the gaps between multiple stone facings 3 and the surface of the tunnel portal wall 1, as well as between the connectors and the seepage pipes; the minimum layer thickness of the self-compacting concrete 6 is not less than 2 cm, and the diameter of the coarse aggregate constituting the self-compacting concrete 6 is not more than 1.0 cm.

[0097] At the same time, a lightning rod 13 is buried on the top of the tunnel portal wall 1. The lightning rod is connected to all connectors 5 via a wire and then connected to the grounding wire 14. The lightning rod 13 and the grounding wire 14 are both lightning protection components of the tunnel portal wall 1. The depth of the lightning rod 13, the wire and the grounding wire 14 must meet the technical requirements of secondary lightning protection.

[0098] The plurality of anchor bolts 4 are the main force-bearing components of the stone facing 3 structure on the tunnel portal wall 1. The anchor bolts 4 are of length A steel bar with a threaded end and a diameter of In the anchor holes, multiple anchor holes are aligned with the horizontal plane. Drill holes in the tunnel portal wall 1. The gaps between the anchor holes and the anchors 4 are bonded by high-strength cement mortar 41, and the nuts 42 are anchored with the wedge-shaped pads 43 and the connectors 5 connecting the multiple anchors 4, and the connectors are then connected with the T-shaped plate inserts 52 or the 7-shaped plate inserts 53 by bolts 55; the wedge-shaped pads 43 have a wedge-shaped inclination angle of The plane arrangement of the plurality of anchor bolts 4 is adjusted accordingly with respect to the different positions of the arch ring 11 and their spacing and plane positions.

[0099] The diameter of each anchor bolt 4 is , with the horizontal plane The corner anchor is fixed on the tunnel portal wall 1, that is, it is fixed obliquely from top to bottom. The total length of each anchor bolt 4 is , terminal The length of the threaded bolt is threaded and anchored to the connecting piece 5 through a nut 42 and a wedge-shaped pad 43. The anchor bolt 4 and the connecting piece 5 are elastically embedded and connected. The anchor bolt 4 is anchored in the anchor bolt hole on the tunnel portal wall 1 for an anchor length of The anchor holes are bonded with cement mortar 41. The anchor bolts 4 are subjected to the self-weight of the self-compacting concrete 6, the stone facing 3, the self-weight of the connector 5, ice and snow, natural wind, driving vibration, vehicle piston wind and other external forces. Each anchor bolt 4 is an elastic foundation beam with one end elastically embedded and one end free. , free end The tensile elastic coefficient and compressive elastic coefficient of cement mortar 41 are The comprehensive elastic coefficient is equal to the sum of the tension elastic coefficient and the pressure elastic coefficient. The comprehensive elastic reaction force is According to the elastic foundation beam mechanics theory, the anchor bolt force is calculated as follows:

[0100] Formula 1:

[0101]

[0102] From the above formula, we can get

[0103] From the above equations, we can find ;

[0104] Formula 2:

[0105]

[0106] The symbols in Formula 1 and Formula 2 are defined as:

[0107] ——The force reserved by anchor bolt 4 on tunnel portal wall 1 The horizontal calculated length of the action point, ;

[0108] ——Anchor bolt Length of anchoring on the tunnel portal wall, ;

[0109] - diameter of anchor bolt 4, ;

[0110] - diameter of the anchor hole, ;

[0111] ——the angle between anchor bolt 4 and the horizontal line, ;

[0112] ——Based on the center of the anchor bolt on the tunnel portal wall 1 Point is the coordinate value of the origin along the length of anchor bolt 4, ;

[0113] ——The center of anchor bolt 4 on tunnel portal wall 1 The point is the origin and perpendicular to the anchor bolt The deformation curve equation of the length is the anchor bolt The deformation value at ;

[0114] ——Anchor bolt The absolute value of the maximum deformation at ;

[0115] ——Respectively, they are the comprehensive elastic coefficient, tension elastic coefficient and pressure elastic coefficient of cement mortar 41, which are determined through tests. In the absence of test data, they are determined according to relevant specifications. ;

[0116] ——Comprehensive elastic reaction force , ;

[0117] - bending stiffness of anchor bolt 4, ;

[0118] ——The horizontal calculated length acting on the anchor bolt 4 from the surface of the tunnel portal wall 1 The load of a single anchor bolt at the outer end A includes the self-weight of the self-compacting concrete 6, the stone facing 3, the self-weight of the connector 5, and the external forces of ice and snow, natural wind, driving vibration, and vehicle piston wind. , ;

[0119] ——The load acting on a single anchor bolt 4 includes the self-weight of the self-compacting concrete 6, the stone facing 3, the self-weight of the connector 5, and the conventional total load of ice, snow, and natural wind. ;

[0120] ——Vehicle piston wind load. When a vehicle drives to the tunnel entrance, due to the space limitation of the tunnel wall, the air pushed by the vehicle cannot all flow around to the rear of the vehicle. Some air will inevitably be pushed forward by the vehicle, and there is a negative pressure area behind the rear end of the vehicle. This is called the "piston effect". At this time, the tunnel portal wall generates a vehicle piston wind pull load into the tunnel portal. The vehicle piston wind load is related to many factors such as the vehicle speed, the number of vehicles, the tunnel entrance environment, and the friction resistance of the inner wall of the tunnel. The vehicle piston wind load acting on a single anchor bolt is The force is obtained by testing. ;

[0121] ——The driving vibration coefficient acting on a single anchor bolt 4 is determined through tests. In the absence of test data, it is determined by referring to relevant specifications, or it is taken as 1.05 to 1.45 for a stable driving state of the vehicle depending on the smoothness of the road surface at the tunnel entrance;

[0122] ——Anchor bolts Bending moment, shear force and rotation at ;

[0123] ——Action on anchor bolts Moment and shear force at the end, ;

[0124] ——Action on anchor bolts B Moment and shear force at the end, ;

[0125] --coefficient, , ;

[0126] ——Deformation coefficient of anchor bolt 4 calculated as elastic foundation beam;

[0127] ——are the allowable bending moment and allowable shear strength of anchor bolt 4, ;

[0128] ——are the allowable tensile strength and allowable compressive strength of cement mortar 41, .

[0129] In addition, the tunnel portal wall stone facing structure construction method comprises the following steps:

[0130] Step 1: Investigation, testing and design calculation

[0131] According to the construction scale of tunnel portal wall 1, a preliminary design of the structural scheme of stone facing is made, and technical requirements and standards of the materials used are proposed;

[0132] Determined by test, or in the absence of test data, the comprehensive elastic coefficient, tension elastic coefficient and pressure elastic coefficient of cement mortar 41 are determined according to relevant specifications ;

[0133] Through investigation and calculation of the load acting on a single anchor bolt 4, including the self-weight of the self-compacting concrete 6, the stone facing 3, the self-weight of the connector 5, and the conventional total load of ice, snow, and natural wind;

[0134] By detecting and calculating the vehicle piston wind load acting on a single anchor bolt 4;

[0135] Determined by test, or in the absence of test data, determined by referring to relevant specifications or selecting the driving vibration coefficient for the vehicle's stable driving state based on the smoothness of the road surface at the tunnel entrance;

[0136] Calculate the anchor bolt length, specification size and material requirements by formula 1 and formula 2;

[0137] Design detailed construction drawings, determine raw materials, construction technical requirements and standards;

[0138] Step 2: Make the structural components of the stone veneer

[0139] Check whether the dimensions of the tunnel portal wall are consistent with the design drawings;

[0140] ② Make seepage pipes and connectors according to the design drawings, with the quantity and quality meeting the design requirements;

[0141] Select the appearance, color and texture of the stone facing according to the design drawings, and cut the external dimensions, grooves, quantity and specifications to meet the design requirements;

[0142] Step 3: Set up construction scaffolding

[0143] Build construction scaffolding along the tunnel portal wall, and the reserved width between the scaffolding and the tunnel portal wall should be convenient for construction operations;

[0144] ② Clean the concrete residue and cement slurry on the tunnel portal wall, and roughen the concrete where it is too smooth;

[0145] Mark out the stone facing blocks according to the design drawings, and mark the anchor bolt position marks and seepage pipe position marks;

[0146] Step 4: Install the seepage pipe

[0147] Install the longitudinal seepage pipe 22 and the transverse seepage pipe 21 from top to bottom, and fix the seepage pipe 2 with cement nails and iron wire;

[0148] ② The joints between the longitudinal seepage pipe 22 and the transverse seepage pipe 21 are sealed with silicone structural sealant;

[0149] The lowest interface of the seepage pipe 2 is connected to the longitudinal drainage ditch of the tunnel;.

[0150] Step 5: Stone facing construction

[0151] Determine the raw materials and mix ratio of cement mortar 41, self-compacting concrete 6 and silicone structural sealant through experiments;

[0152] ② Drill anchor holes. The hole diameter and depth of the anchor holes meet the design requirements. After drilling, use an air compressor to clean the holes;

[0153] Mix cement mortar, pour mortar into the first hole, and test-insert the anchor bolt to determine the amount of mortar to avoid excessive waste; pour cement mortar 41 into the anchor bolt hole, rotate the anchor bolt back and forth to the bottom until the hole overflows the mortar, and hang the geotextile externally to sprinkle water for curing for a specified time;

[0154] Install the connector 5 between the first row of square facings and the first curved facing at the bottom, install the first row of square facings and the first curved facing at the bottom, and adjust the plane position of the square facings accurately; reserve a separation gap 36 on the side of the first row of square facings and the side of the first curved facing at the bottom, fill the separation gap with a foam strip, and fill the outside of the foam strip with a silicone structural sealant for sealing;

[0155] After the silicone structural sealant is cured, pour the mixed self-compacting concrete into the gap between the first row of square facings, the first curved facing and the tunnel portal wall. Use a wooden hammer to gently tap the first row of square facings and the first curved facing underneath. After the self-compacting concrete is poured densely, clean the concrete slurry in the top side groove of the first row of square facings underneath, and cover with geotextile for maintenance.

[0156] Follow this step , Install the upper row and the rows above the square facings. If the height of the upper row or the rows above the upper row is higher than the first curved facing below, continue to install the second curved facing at the same time, so that the curved facing at the arch ring is installed synchronously with the square facing. The upper and lower rows, the periphery of the same row, and the separation seams with the curved facings are filled with foam strips and silicone structural sealant for sealing. After the silicone structural sealant is cured, pour the self-compacting concrete. The arch ring is installed symmetrically. After the square facings are installed, mortar is laid on the top of the highest row of square facings, and the strip facings are installed;

[0157] Step 6: Install lightning protection device

[0158] Bury a grounding wire 14 in front of the bottom first row of square facings and the bottom first curved facing;

[0159] ② After the anchor bolts 4 and connectors 5 are installed, use wires to connect all connectors and access the grounding wire 14, and reserve a connecting wire from the highest row of connectors to the top lightning rod 13;

[0160] Lay cement mortar 41 on the top of the highest row of square facings and embed the top lightning rod 13 before installing the strip facings 32;

[0161] Step 7: Stone surface maintenance and quality inspection

[0162] During the construction process of pouring cement mortar 41 into the anchor bolts 4 until all the stone facings 3 are constructed, attention is paid to the construction quality, and necessary tests and inspections are carried out, and timely maintenance is carried out to ensure the internal quality. The width of the dividing seams 36 is consistent, the dividing lines of the stone facings 3 are straight, the vertical dividing seams 36 are staggered with each other without leaving vertical through seams, and the appearance is flat and beautiful.

[0163] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design similar to this embodiment should be included in the protection scope of the present invention.

Claims

1. A tunnel portal wall stone facing structure, comprising a wall surface (12) and an arch ring (11) constituting a tunnel portal wall (1), and a plurality of square facings (31), a plurality of strip facings (32) and a plurality of arc facings (33) constituting a stone facing (3), characterized in that The plurality of square facings (31) are evenly laid on the wall surface (12); a face groove (35) and a 7-shaped plate insert embedded in the face groove are provided in the middle of the back of each square facing (31); a side groove (34) is provided on the upper edge and the lower edge of each square facing (31); a T-shaped plate insert is provided between the side grooves (34) of each two adjacent square facings (31); and the 7-shaped plate insert and the T-shaped plate insert are connected to the anchor bolt (4) obliquely anchored on the tunnel portal wall (1) via a connecting piece (5); the plurality of strip facings (32) are horizontally laid on the top of the wall surface (12); each strip facing ( 32) are bonded and connected to adjacent square facings (31); the plurality of arc-shaped facings (33) are laid along the outer edge of the arch ring (11); the middle of the back of each arc-shaped facing (33) is provided with a surface groove (35) and a 7-shaped plate insert embedded in the surface groove; the 7-shaped plate insert is connected to an anchor bolt (4) obliquely anchored on the tunnel portal wall (1) via a connecting piece (5); a plurality of seepage pipes (2) arranged in the longitudinal and transverse directions and poured self-compacting concrete (6) are provided between the stone facing (3) and the tunnel portal wall (1); each adjacent two stone facings (3) are sealed and glued; the diameter of each anchor bolt (4) is , with the horizontal plane The corners are anchored on the tunnel portal wall (1), and the total length of each anchor bolt (4) is , terminal The length of the threaded hole is machined and anchored to the connecting piece (5) through a nut (42) and a wedge-shaped pad (43). The anchor bolt (4) and the connecting piece (5) are elastically embedded and connected. The anchor bolt (4) is anchored in the anchor bolt hole on the tunnel portal wall (1) for an anchoring length of The anchor holes are bonded with cement mortar (41). The anchor bolts (4) are subjected to the self-weight of the self-compacting concrete (6), the stone facing (3), the self-weight of the connecting piece (5), and the external forces of ice and snow, natural wind, driving vibration, and vehicle piston wind. Each anchor bolt (4) is subjected to the force of an elastic foundation beam with one end elastically embedded and the other end free. , free end The tensile elastic coefficient and compressive elastic coefficient of cement mortar (41) are The comprehensive elastic coefficient is equal to the sum of the tension elastic coefficient and the pressure elastic coefficient. The comprehensive elastic reaction force is According to the elastic foundation beam mechanics theory, the anchor bolt force is calculated as follows: Formula 1: From the above formula, we can get From the above equations, we can find ; Formula 2: The symbols in Formula 1 and Formula 2 are defined as: ——The force reserved by the anchor bolt (4) on the tunnel portal wall (1) The horizontal calculated length of the action point, ; ——Anchor bolt Length of anchoring on the tunnel portal wall, ; - diameter of the anchor bolt (4), ; - diameter of the anchor hole, ; - the angle between the anchor bolt (4) and the horizontal line, ; ——Based on the center of the anchor bolt on the tunnel portal wall (1) Point is the coordinate value of the origin along the length of the anchor bolt (4), ; ——The center of the anchor bolt (4) on the tunnel portal wall (1) The point is the origin and perpendicular to the anchor bolt The deformation curve equation of the length is the anchor bolt The deformation value at ; ——Anchor bolt The absolute value of the maximum deformation at ; ——are the comprehensive elastic coefficient, tensile elastic coefficient and compressive elastic coefficient of cement mortar (41), which are determined through experiments. In the absence of test data, they are determined according to relevant specifications. ; ——Comprehensive elastic reaction force , ; - bending stiffness of the anchor bolt (4), ; ——The horizontal calculated length of the anchor bolt (4) from the surface of the tunnel portal wall (1) The load of a single anchor bolt at the outer end A includes the deadweight of the self-compacting concrete (6), the deadweight of the stone facing (3), the deadweight of the connecting piece (5), and the external forces of ice and snow, natural wind force, driving vibration, and vehicle piston wind. , ; ——The load acting on a single anchor bolt (4) includes the self-weight of the self-compacting concrete (6), the stone facing (3), the self-weight of the connector (5), and the conventional total load of ice, snow, and natural wind forces. ; ——Vehicle piston wind load. When a vehicle drives to the tunnel entrance, due to the space limitation of the tunnel wall, the air pushed by the vehicle cannot all flow around to the rear of the vehicle. Some air will inevitably be pushed forward by the vehicle, and there is a negative pressure area behind the rear end of the vehicle. This is called the "piston effect". At this time, the tunnel portal wall generates a vehicle piston wind pull load into the tunnel portal. The vehicle piston wind load is related to many factors such as the vehicle speed, the number of vehicles, the tunnel entrance environment, and the friction resistance of the inner wall of the tunnel. The vehicle piston wind load acting on a single anchor bolt is The force is obtained by testing. ; - the vibration coefficient of the vehicle acting on a single anchor bolt (4), which shall be determined through tests. In the absence of test data, it shall be determined by referring to relevant specifications, or it may be determined by taking 1.05 to 1.45 for a vehicle in a stable driving state depending on the smoothness of the road surface at the tunnel entrance; ——Anchor bolts Bending moment, shear force and rotation at ; ——Action on anchor bolts Moment and shear force at the end, ; ——Action on anchor bolts B Moment and shear force at the end, ; --coefficient, , ; - the deformation coefficient of the anchor bolt (4) calculated as an elastic foundation beam; ——are the allowable bending moment and allowable shear strength of the anchor bolt (4), ; ——are the allowable tensile strength and allowable compressive strength of cement mortar (41), .

2. A tunnel portal wall stone facing structure according to claim 1, characterized in that The connecting piece (5) comprises an inner angle steel connecting piece (512) and an outer angle steel connecting piece (511); the T-shaped plate insert (52) is connected to an anchor bolt (4) obliquely anchored on the tunnel portal wall (1) via the outer angle steel connecting piece (511); the 7-shaped plate insert (53) is connected to an anchor bolt (4) obliquely anchored on the tunnel portal wall (1) via the inner angle steel connecting piece (512); and a cross plate (54) connected to each other is provided between the inner angle steel connecting piece (512) and the outer angle steel connecting piece (511).

3. The tunnel portal wall stone facing structure according to claim 1, characterized in that A lightning rod (13) is buried on the top of the tunnel portal wall (1), and the lightning rod is connected to all the connectors (5) via a conductor and then connected to a grounding wire (14).

4. The tunnel portal wall stone facing structure according to claim 1, characterized in that The seepage pipe (2) is durable ASA The modified resin pipe has an outer diameter of 1.5 cm to 2.0 cm and a wall thickness of 1.5 mm to 2.0 mm. The seepage pipe (2) is covered with a double-layer geotextile and arranged along the wall surface (12) of the tunnel portal wall (1) at intervals of 50 cm to 100 cm in the longitudinal and transverse directions. The interconnections between the seepage pipes (2) are sealed with resin glue. The longitudinal seepage pipe (22) is perforated with plum blossom-shaped holes every 50 cm to 100 cm to penetrate the entire cross section. The transverse seepage pipe (21) is perforated with plum blossom-shaped semicircles every 50 cm to 100 cm toward the upper part. The seepage pipe (2) is tied to the connecting piece (5), and the lowest end interface of the seepage pipe (2) is connected to the longitudinal drainage ditch of the tunnel.

5. The tunnel portal wall stone facing structure according to claim 1, characterized in that Each of the square facings (31) has a length of 110 cm to 120 cm, a width of 50 cm to 60 cm, and a thickness of 2.8 cm to 3.2 cm; each of the arc-shaped facings (33) has a length of 80 cm to 120 cm, a width equal to the width of the arch ring, and a thickness of 2.8 cm to 3.2 cm; each of the strip-shaped facings (32) has a length of 110 cm to 120 cm, a width of 20 cm to 30 cm, and a thickness of 8 cm to 10 cm; a side groove (34) is cut in the middle of the upper edge and the lower edge of the square facing (31); the side groove has a size of not less than 20 mm in height and 0.8 mm in width, and is fixed by a T-shaped plate insert (52); the gap between the side groove (34) and the T-shaped plate insert (52) is 1.5 mm to 2.0 mm; a plurality of surface grooves (35) are cut in the middle of the back of the square facing (31); the size of each surface groove is not less than 120 mm in height and 0.8 mm in width. The width is 20 mm, each surface groove (35) is embedded by a 7-shaped plate insert (53), and the gap between the surface groove (35) and the 7-shaped plate insert (53) is 1.5 mm to 2.0 mm; a plurality of surface grooves (35) are cut out in the middle of the back of the arc-shaped decorative surface (33), and the size of each surface groove is not less than 120 mm in height × 20 mm in width, and each surface groove (35) is embedded by a 7-shaped plate insert (53), and the surface groove (35 ) and the 7-shaped plate insert (53) have a gap of 1.5 mm to 2.0 mm; the strip-shaped facing (32) is bonded to the top of the wall of the tunnel portal wall (1) by cement mortar (41), and hangs out 5 cm to 8 cm from the plane formed by the square facing (31) and the arc-shaped facing (33); a separation joint (36) is provided between each of the two adjacent stone facings (3), and the separation joint is filled with a foam strip and a silicone structural sealant for sealing.

6. The tunnel portal wall stone facing structure according to claim 2, characterized in that The size of the outer angle steel connector (511) is not less than ∟50mm×5mm, and its length is the same as the length of the square facing (31); the size of the inner angle steel connector (512) is not less than ∟50mm×5mm×120mm.

7. The tunnel portal wall stone facing structure according to claim 1, characterized in that The anchor bolt (4) is of length A steel bar with a threaded end and a diameter of In the anchor holes, multiple anchor holes are aligned with the horizontal plane. The corners are drilled in the tunnel portal wall. The gaps between the plurality of anchor holes and the anchor bolts (4) are bonded by high-strength cement mortar (41), and the nuts (42) are anchored with the wedge-shaped pads (43) and the connecting pieces (5) connecting the plurality of anchor bolts (4). The connecting pieces (5) are then connected with the T-shaped plate inserts (52) or the 7-shaped plate inserts (53) by bolts (55); the wedge-shaped pads (43) have a wedge-shaped inclination angle of The plane arrangement of the plurality of anchor bolts (4) is adjusted accordingly with respect to the different positions of the arch ring (11).

8. The tunnel portal wall stone facing structure according to claim 1, characterized in that The self-compacting concrete (6) is a self-compacting fiber concrete, which is a high-performance cement concrete that can be compacted and formed under its own gravity without any vibration. The self-compacting concrete (6) is mixed with polypropylene fiber-like inorganic fibers and filled into the gaps between the stone facing (3) and the surface of the tunnel portal wall (1) and between the connecting piece (5) and the seepage pipe (2). The minimum layer thickness of the self-compacting concrete (6) is not less than 2 cm, and the diameter of the coarse aggregate constituting the self-compacting concrete (6) is not more than 1.0 cm.

9. A method for constructing a tunnel portal wall stone facing structure according to claim 1, characterized in that The construction method comprises the following steps: Step 1: Investigation, testing and design calculation ① Preliminary design of the structural scheme of the stone facing according to the construction scale of the tunnel portal wall (1), and the technical requirements and standards of the materials used; ② Determine through tests, or in the absence of test data, determine the comprehensive elastic coefficient, tensile elastic coefficient and compressive elastic coefficient of cement mortar (41) according to relevant specifications; ③ Investigate and calculate the loads acting on a single anchor bolt (4), including the self-weight of the self-compacting concrete (6), the stone facing (3), the self-weight of the connector (5), and the conventional total load of ice, snow, and natural wind; ④ By detecting and calculating the vehicle piston wind load acting on a single anchor bolt (4); ⑤ Determine through tests, or in the absence of test data, determine by referring to relevant specifications or select the driving vibration coefficient for the vehicle's stable driving state based on the smoothness of the road surface at the tunnel entrance; ⑥ Calculate the anchor bolt length, specifications, and material requirements using Formula 1 and Formula 2; ⑦ Design detailed construction drawings, determine raw materials, construction technical requirements and standards; Step 2: Make the structural components of the stone veneer ① Check whether the dimensions of the tunnel portal wall (1) are consistent with the design drawings; ② Produce the seepage pipe (2) and the connecting piece (5) according to the design drawings, with the quantity and quality meeting the design requirements; ③ Select the appearance, color, and texture of the stone facing (3) according to the design drawings, and cut the external dimensions, grooves, quantity, and specifications to meet the design requirements; Step 3: Set up construction scaffolding ① Build a construction scaffold along the tunnel portal wall (1), and reserve a width between the scaffold and the tunnel portal wall to facilitate construction operations; ② Clean the concrete residue and cement slurry on the tunnel portal wall, and roughen the concrete where it is too smooth; ③ Mark the stone facing blocks according to the design drawings, and mark the anchor bolt position and seepage pipe position; Step 4: Install the seepage pipe ① Install the longitudinal seepage pipe (22) and the transverse seepage pipe (21) from top to bottom, and fix the seepage pipe (2) with cement nails and iron wire; ② The joint between the longitudinal seepage pipe (22) and the transverse seepage pipe (21) is sealed with a silicone structural sealant; ③ The bottom interface of the seepage pipe (2) is connected to the longitudinal drainage ditch of the tunnel; Step 5: Stone facing construction ① Determine the raw materials and mix ratio of cement mortar (41), self-compacting concrete (6) and silicone structural sealant through experiments; ② Drill anchor holes. The hole diameter and depth of the anchor holes meet the design requirements. After drilling, use an air compressor to clean the holes; ③ Mix cement mortar (41), pour mortar into the first hole and test-insert the anchor bolt to determine the amount of mortar to be poured to avoid excessive waste; pour cement mortar into the anchor bolt hole, rotate the anchor bolt back and forth to the bottom until the mortar overflows from the hole, and hang the geotextile externally to sprinkle water for curing for a specified time; ④ Install the connector (5) between the first row of square facings and the first curved facing at the bottom, install the first row of square facings (31) and the first curved facing at the bottom (33), and adjust the plane position of the square facing (31) accurately; reserve a separation gap (36) on the side of the first row of square facings (31) and the side of the first curved facing at the bottom (33), fill the separation gap with a foam strip, and fill the outside of the foam strip with a silicone structural sealant for sealing; ⑤ After the silicone structural sealant is cured, the prepared self-compacting concrete (6) is poured into the gap between the first row of square facings (31), the first curved facing (33) and the wall surface (12) of the tunnel portal wall (1), and the first row of square facings (31) and the first curved facing (33) are gently tapped with a wooden hammer. After the self-compacting concrete (6) is poured and compacted, the concrete slurry in the top side groove (34) of the first row of square facings (31) is cleaned, and the geotextile is covered for curing; ⑥ Install the upper row and the rows above the square facings according to steps ④ and ⑤. If the height of the upper row or the rows above the square facings is higher than the first curved facing below, continue to install the second curved facing at the same time, so that the curved facings at the arch ring are installed synchronously with the square facings. The upper and lower rows, the periphery of the same row, and the separation gaps with the curved facings are filled with foam strips and silicone structural sealant for sealing. After the silicone structural sealant is cured, pour self-compacting concrete. An arch ring (11) is installed symmetrically. After the square facings (31) are installed, mortar is laid on the top of the highest row of square facings, and the strip facings (32) are installed. Step 6: Install lightning protection device ① burying a grounding wire (14) in front of the bottom first row of square facings (31) and the bottom first arc-shaped facing (33); ② After the anchor bolts (4) and connectors (5) are installed, all connectors (5) are connected to the ground wire using wires, and a connecting wire is reserved from the highest row of connectors (5) to the top lightning rod (13); ③ Lay cement mortar (41) on the top of the highest row of square facings (31) and embed the top lightning rod (13) before installing the strip facings (32); Step 7: Stone surface maintenance and quality inspection During the construction process of pouring cement mortar (41) into the anchor bolts (4) and until all the stone facing surfaces (3) are constructed, attention is paid to the quality of the engineering construction, and necessary tests and inspections are carried out. Timely maintenance is carried out to ensure the internal quality. The width of the separation joints (36) is consistent, the dividing lines of the stone facing surfaces (3) are straight, the vertical separation joints are staggered to leave no vertical through joints, and the appearance is smooth and beautiful.

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