Limited clearance lower corridor construction method and construction device thereof

Abstract

The invention discloses a limited clearance lower corridor construction method and a construction device thereof. Belongs to the technical field of building construction. Aiming at the problems of low construction efficiency, unstable structural connection, poor integration effect and the like in corridor construction in a limited clearance environment, a solution is provided: a compact piling drill bit is adopted, and the compact piling drill bit is provided with a special structure, a quick-assembly and quick-disassembly interface and a high-strength alloy head; a sleeve with a high-precision thread, a sealing rubber ring and a reinforcing rib plate is used for concrete filled steel tube connection, and pressure grouting is matched; the integrated board is integrally prefabricated and positioned and installed through pressure grouting. According to the technology, the construction efficiency can be improved, the structural stability and waterproof performance are enhanced, the construction difficulty is reduced, and the technology is suitable for corridor construction in limited clearance scenes such as old urban areas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building construction technology, in particular to a gallery construction method and device suitable for limited space environment with a clear height ≤5m and a transverse operation width ≤3.5m, which comprises a compact pile drilling head, a connection sleeve with high-precision threads, and an integrated prefabricated plate surface with a rabbet joint at the edge, and is mainly used for gallery construction in limited space scenes such as old urban areas and above underground structures. BACKGROUND

[0002] In the field of building construction, the demand for gallery engineering construction in limited clearance environments (such as old urban areas, above underground structures, etc. with a clear height ≤5m and a transverse operation width ≤3.5m) is increasing. The current traditional construction technology has the following structural defects in such scenes: Insufficient space adaptability of piling equipment Traditional pile drilling heads adopt a large-size cylindrical structure, with a diameter generally ≥800mm, a length ≥3m, a length-diameter ratio >3:1, and the drilling head and drill rod are connected by flange bolts (requiring 8-12 bolts to be fixed). Such design causes the equipment to be unable to rotate flexibly in a space with a clear height <6m or a transverse width <4m, and is prone to collision with the surrounding built structures. For example, in a gallery construction in an old residential area, due to the site clear height of only 4m, the traditional drilling head cannot be vertically lowered, and the pile machine angle needs to be repeatedly adjusted, which increases the time consumption for single-hole forming by more than 2 times compared with open sites. In addition, the traditional drilling head interface has no sealing structure, and the invasion of mud easily causes the drill rod connection to loosen, which requires frequent stoppage for maintenance.

[0003] Structural defects of steel pipe concrete connection The existing gallery steel pipe concrete connection mainly relies on welding technology, and the steel pipe butt joint needs to reserve ≥500mm welding operation space, which is difficult to implement in limited clearance. The inner wall of the connection sleeve is not processed with threads, and the steel pipe is only fixed by girth welding, with a welding seam thickness ≤6mm, and the sleeve has no external reinforcing rib plate, resulting in a pullout bearing capacity of the connection part ≤400kN (design value 450kN). In terms of sealing, only a single layer of sealant (thickness ≤3mm) is applied on the outside of the sleeve, which cannot resist groundwater seepage. The detection of a certain project shows that the leakage rate of the traditional connection method is as high as 18%. The grouting process adopts self-weight pouring, and the hollow rate of the sleeve is ≥10%, affecting the integrity of the structure.

[0004] Hidden dangers of splicing joints in plate installation Traditional corridor slab surface adopts block installation process, the size of single prefabricated slab is ≤2m*2m, there is no rabbet joint design at the edge, and the width of splicing joint is ≥8mm. Reinforcing steel bar connection adopts on-site binding lap joint (lap joint length ≥400mm), and it needs to additionally support and pour concrete, so the construction period is long. There is no reserved grouting hole on the slab surface, and the waterproofing relies on the later laying of coiled material, and the lap joint is prone to cracking. After 3 years of use, 85% of the splicing joints of a project leak, and the maintenance cost accounts for 15% of the total cost.

[0005] Cause analysis of prior art The root cause of the above problems lies in that the prior art does not perform systematic structural optimization for the three-dimensional space constraint of limited headroom: The piling equipment does not consider compact design, resulting in size overrun; The steel pipe connection lacks mechanical locking structure and sealing system, and relies on inefficient welding; The slab installation does not adopt integrated prefabrication and pressure grouting technology, and the splicing joint becomes a weak point in performance.

[0006] Therefore, it is urgent to develop a corridor construction device and method suitable for limited headroom to solve the structural defects of traditional process. Summary of the invention

[0007] The present application provides a corridor construction device composed of a compact piling bit, a high-precision threaded connection sleeve and a rabbet joint prefabricated slab surface for the space constraint of limited headroom (headroom height ≤5m, transverse operation width ≤3.5m), and a construction method with "mechanical locking connection + pressure grouting + integrated installation" as the core to solve the structural problems such as equipment size overrun, welding operation limitation and splicing joint leakage in traditional process.

[0008] In order to achieve the above purpose, the present application is realized by the following technical scheme: a corridor construction method under limited headroom, comprising the following steps: Step S1, a compact piling bit with a length and diameter reduced by 20%-30% compared with a traditional bit is used, and the compact piling bit is connected with a drill rod through a quick-mounting and quick-dismounting interface, and the quick-mounting and quick-dismounting interface is a mechanical locking structure; Step S2, a connection sleeve with high-precision threads is sleeved on the inner wall at the butt joint of the corridor steel pipe, a plurality of sealing rubber rings are arranged between the sleeve and the steel pipe, and the inside of the sleeve is filled with grouting material; Step S3, an integrated slab surface prefabricated in a factory is connected with the reserved reinforcing steel bars of the main structure through the reserved positioning reinforcing steel bars of the slab surface, and a pressure grouting process is used for reinforcing connection.

[0009] Further, the compact piling bit head is made of tungsten-cobalt alloy material, a sealing structure is arranged at the connection interface between the bit and the drill rod, and the sealing structure comprises a rubber sealing ring embedded in the gap of the interface.

[0010] Further, as an improvement of the technical scheme of the present application, the inner wall thread of the connecting sleeve matches the thread pitch and tooth angle of the outer wall of the steel pipe, and the outer part of the sleeve is provided with a radial distribution of reinforcing rib plates, the thickness of the reinforcing rib plates is 8-12mm, and the interval is ≤100mm.

[0011] Further, as an improvement of the technical scheme of the present application, the integrated prefabricated plate surface forms an integral reinforcing cage when cast in the factory, and the plate surface is provided with a grouting hole with a diameter of 50mm, and the hole position accuracy is ±2mm.

[0012] Further, as an improvement of the technical scheme of the present application, a limited clearance corridor construction device comprises: The compact pile drilling head comprises a tungsten-cobalt alloy material head, a quick-mounting and quick-dismounting mechanical locking interface, and a double-channel O-shaped sealing ring, and the overall length-diameter ratio of the drilling head is ≤2.5:1; The steel pipe concrete connecting sleeve is provided with a trapezoidal thread with a pitch of 2-3mm and a tooth angle of 60° on the inner wall, a sealing groove with a width of 10mm and a depth of 8mm in the inside, and a radial reinforcing rib plate with a thickness of 8-12mm on the outside; The integrated prefabricated plate surface is provided with a rabbet joint with a depth of 30mm on the edge, the internal reinforcing cage is formed as a whole by mechanical connection or welding, and the plate surface is provided with a positioning reinforcing bar with a diameter of 20mm and a grouting hole with a diameter of 50mm.

[0013] Further, as an improvement of the technical scheme of the present application, the quick-mounting and quick-dismounting mechanical locking interface comprises a cam locking mechanism and an anti-loosening and anti-back-off ring, and the interface fitting gap is ≤0.1mm.

[0014] Further, as an improvement of the technical scheme of the present application, the sealing rubber ring is made of ethylene-propylene-diene rubber material, with a cross-sectional diameter of 8mm, and is installed in the sealing groove between the sleeve and the steel pipe.

[0015] Further, as an improvement of the technical scheme of the present application, the connecting sleeve is made of Q345B steel material, with a length of 1.5-2 times the outer diameter of the steel pipe, and the grouting hole is provided at the center of the top of the sleeve with a diameter of 25mm.

[0016] Further, as an improvement of the technical scheme of the present application, the integrated prefabricated plate surface is cast with C40 waterproof concrete, with an impermeability grade ≥P8, and the reinforcing cage is made of HRB400 reinforcing steel with an interval of 150mm×150mm.

[0017] Further, as an improvement of the technical scheme of the present application, the rabbet joint of the prefabricated plate surface is a convex-concave matching structure, with a rabbet width of 50mm, and the overlapping length of the positioning reinforcing bar is ≥300mm.

[0018] The present application has the following beneficial effects: I. Construction efficiency is significantly improved Compact drill bit space adaptability The overall size of the pile drill bit is reduced by 20%-30% compared to traditional processes, the length-diameter ratio is ≤2.5:1, it can be flexibly rotated in a narrow space with a clearance height ≤4m and a lateral width ≤2.6m, avoiding collision with the surrounding structure. The quick-mounting and quick-dismounting interface (mechanical locking structure) shortens the drill bit replacement time from several hours in traditional processes to within 5 minutes, reduces the single pile hole forming time by 50%, and increases the single day pile driving amount by 100%.

[0019] Efficiency of prefabricated assembly process The integrated prefabricated slab is completed by overall pouring in the factory, and the laser positioning system (accuracy ±2mm) is used for rapid hoisting on site. The installation time of a single 6m×3m slab is only 30% of that of the traditional block splicing process (9 blocks are required for a single 2m×2m block), and the overall construction period is shortened by more than 40%.

[0020] II. The structural connection strength and stability are significantly enhanced High-precision threaded sleeve mechanical locking The steel pipe and the sleeve are matched through trapezoidal threads with a pitch of 2-3mm and a tooth angle of 60°, the tightening torque is ≥1200N・m, and the external radial reinforcing rib plate (thickness 8-12mm) makes the connection uplift bearing capacity increase by more than 30% (actual measurement ≥600kN, traditional welding process ≤400kN), and the ultrasonic detection weld joint qualification rate is 100%.

[0021] Pressure grouting compactness 0.3-0.6MPa pressure grouting high-strength grouting material (28-day compressive strength ≥60MPa) is used in the sleeve, the filling saturation is ≥98%, a steel pipe-grouting material-sleeve collaborative stress system is formed, the structural integrity is improved, the standard deviation of compressive strength is ≤2MPa, and the dispersion of traditional self-weight grouting is reduced by 60%.

[0022] III. Water resistance and durability are greatly optimized Reliability of multi-seal system Three sealing rubber rings (EPDM, cross-sectional diameter 8mm) are arranged between the connecting sleeve and the steel pipe, cooperating with the sealing groove structure, no leakage is found under 0.5MPa water pressure test, the waterproof level reaches IP67 standard, and the leakage rate is reduced from 15%-20% in traditional processes to ≤1%.

[0023] Seamless splicing of integrated slab The prefabricated plate surface edge is provided with a rabbet joint (depth 30mm), and the whole connection is formed by pressure grouting (grouting material strength C45) on site, the splicing joint width is less than or equal to 1.5mm, the leakage amount of the closed water test is less than or equal to 0.05L / (m.h), and the impermeability grade reaches P8, and the waterproof performance is improved by 93% compared with the traditional block installation.

[0024] Four, construction operation difficulty and labor intensity are reduced Reduce high-altitude welding operation The new type of connecting sleeve does not need to be welded on site, reduces 80% of high-altitude operation amount, avoids welding smoke hazards in limited space, and significantly improves construction safety.

[0025] Convenience of modular construction Standardized components are used in each process of piling, steel pipe connection and plate surface installation, the operation process is simplified, the construction personnel are reduced by 30%, the labor intensity is reduced from level III (heavy labor) to level II (moderate labor), and the man-machine engineering demand in limited space is adapted.

[0026] Five, comprehensive economic benefit is improved Construction period cost: the construction period is shortened by more than 40%, and the mechanical rental and labor cost is reduced by 30%-40%; Maintenance cost: the waterproof performance improvement makes the leakage maintenance cost reduced by more than 80% in the later period, and the service life of the structure is prolonged by more than 10 years; Environmental benefits: reduce on-site wet work and construction waste, meet the requirements of green construction. DETAILED DESCRIPTION

[0027] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the attached drawings: Fig. 1 is a schematic view of a compact pile drilling bit structure according to an embodiment of the present application; Fig. 2 is a schematic view of a connecting sleeve structure according to an embodiment of the present application; Fig. 3 is a prefabricated plate surface connecting node diagram according to an embodiment of the present application.

[0028] In the drawings: 1-compact pile drilling bit; 11-fast locking interface; 12-tungsten cobalt alloy head; 121-flow guide groove. DETAILED DESCRIPTION

[0029] The present application will be described in detail below with reference to the drawings and specific embodiments. The schematic embodiments and descriptions of the present application are used to explain the present application, but not as a limitation of the present application.

[0030] It should be noted that all the direction indications (such as up, down, left, right, front, back, upper end, lower end, top, bottom, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the direction indications will also change accordingly.

[0031] In the present application, unless otherwise explicitly specified and limited, the term "connection" should be understood in a broad sense, for example, the "connection" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be internal communication of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above-mentioned term in the present application can be understood according to the specific circumstances.

[0032] In addition, in the present application, the description such as "first", "second", etc. is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features; in addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0033] The present application will be further described in detail below in combination with the drawings.

[0034] A limited clearance corridor construction method, comprising the following steps: Step S1, a compact pile drilling bit with a length and diameter reduced by 20%-30% compared with a traditional drilling bit is used, and the compact pile drilling bit is connected with a drill rod through a quick-mounting and quick-dismounting interface, and the quick-mounting and quick-dismounting interface is a mechanical locking structure; Step S2, a connecting sleeve with high-precision threads processed on the inner wall is sleeved at the butt joint of the corridor steel pipe, a plurality of sealing rubber rings are arranged between the sleeve and the steel pipe, and the inside of the sleeve is filled with grouting material; Step S3, an integrated slab prefabricated in a factory is connected with the reserved steel bars of the main structure through the reserved positioning steel bars of the slab, and a pressure grouting process is used for reinforcing connection.

[0035] Specifically, in the embodiment, the head of the compact pile drilling bit is made of tungsten-cobalt alloy material, and a sealing structure is arranged at the connecting interface between the drilling bit and the drill rod, and the sealing structure comprises a rubber sealing ring embedded in the gap of the interface.

[0036] Specifically, in the embodiment, the inner wall thread of the connecting sleeve matches the outer wall thread of the steel pipe in pitch and tooth angle, the sleeve is externally provided with radially distributed reinforcing rib plates, the thickness of the reinforcing rib plates is 8-12 mm, and the interval is ≤100 mm.

[0037] Specifically, in the embodiment, the integrated prefabricated slab is formed with an integral reinforcement framework when cast in a factory, and the slab is provided with a grouting hole with a diameter of 50 mm and a position accuracy of ±2 mm.

[0038] Specifically, in the embodiment, the limited-clearance corridor construction device comprises: The compact pile-driving drill bit comprises a drill bit head made of tungsten-cobalt alloy, a quick-mounting and quick-dismounting mechanical locking interface, and a double-channel O-shaped sealing ring, and the overall length-diameter ratio of the drill bit is ≤2.5:1. The steel pipe concrete connecting sleeve is internally provided with trapezoidal threads with a pitch of 2-3 mm and a tooth angle of 60°, internally provided with a sealing groove with a width of 10 mm and a depth of 8 mm, and externally provided with radially distributed reinforcing rib plates with a thickness of 8-12 mm. The integrated prefabricated slab is provided with a rabbet joint with a depth of 30 mm at the edge of the slab, the internal reinforcement framework is formed integrally through mechanical connection or welding, and the slab is provided with a positioning steel bar with a diameter of 20 mm and a grouting hole with a diameter of 50 mm.

[0039] Specifically, in the embodiment, the quick-mounting and quick-dismounting mechanical locking interface comprises a cam locking mechanism and an anti-loosening and anti-backup ring, and the interface fitting gap is ≤0.1 mm.

[0040] Specifically, in the embodiment, the sealing rubber ring is made of ethylene-propylene-diene rubber, has a cross-sectional diameter of 8 mm, and is installed in the sealing groove between the sleeve and the steel pipe.

[0041] Specifically, in the embodiment, the connecting sleeve is made of Q345B steel, has a length of 1.5-2 times the outer diameter of the steel pipe, and is provided with a grouting hole with a diameter of 25 mm at the center of the top of the sleeve.

[0042] Specifically, in the embodiment, the integrated prefabricated slab is cast using C40 waterproof concrete, has an impermeability grade of ≥P8, and the reinforcement framework is made of HRB400 steel with a spacing of 150 mm x 150 mm.

[0043] Specifically, in the embodiment, the rabbet joint of the prefabricated slab is a convex-concave matching structure, has a rabbet width of 50 mm, and the positioning steel bar has a lap length of ≥300 mm. Embodiment

[0044] Construction method steps S1: compact drill bit installation and pile foundation drilling Compact pile driver bit with a length-diameter ratio of ≤2.5:1 is selected, connected with the drill pipe through quick-mounting and quick-dismounting mechanical locking interface (cam locking mechanism + anti-loosening and anti-backup ring, with a clearance of ≤0.1mm), the head of the bit is tungsten-cobalt alloy (YC15, cobalt content 12%), and double-channel O-shaped sealing ring (fluorine rubber material, cross-section diameter 6mm) is arranged at the interface. The bit body is provided with 4 spiral guide grooves 121 (groove depth 25mm, spiral angle 35°), and the swing angle is controlled to be ≤5° during drilling, and the single-hole forming depth error is ≤±20mm.

[0045] S2: Threaded connection of steel pipe and sleeve and grouting The end of the steel pipe is processed with external thread with a pitch of 2.5mm and a tooth angle of 60°, and is screwed with the internal thread with the same parameters on the inner wall of the sleeve (tightening torque 1200-1500N.m). The sleeve is made of Q345B steel, with a wall thickness of 12mm and a length of 2 times the outer diameter of the steel pipe, and 8 radially distributed reinforcing rib plates with a thickness of 10mm and a spacing of 80mm are arranged on the outside. Three sealing grooves with a width of 10mm and a depth of 8mm are arranged in the middle of the sleeve, and a three-way ethylene-propylene rubber sealing ring with a cross-section diameter of 8mm is embedded, and C60 micro-expanding grouting material (flowing degree 350mm) is injected through the 25mm diameter grouting hole at the top at a grouting pressure of 0.4-0.6MPa.

[0046] S3: Integrated plate surface rabbet joint butt joint and grouting The prefabricated plate has a size of 6m×3m×0.3m, and a 50mm wide rabbet joint (convex part height 30mm, concave part depth 30mm) is arranged on the edge, and Φ14mm double-layer double-direction HRB400 steel bars (spacing 150mm×150mm) are arranged inside, and the straight thread sleeve is mechanically connected to form an integrated framework, and 12 Φ50mm grouting holes (arranged in a quincunx shape, hole spacing 500mm, position accuracy ±2mm) are reserved. The rabbet joint butt joint error is ≤2mm during hoisting, the reserved Φ20mm positioning steel bar of the plate surface is overlapped with the reserved steel bar of the main body structure by a length of ≥300mm, and C45 grouting material (pressure 0.3MPa) is injected through the grouting hole under pressure.

[0047] Core device structure Compact pile driver bit 1 (Figure 1): composed of a tungsten-cobalt alloy head 12 with a diameter of 600mm, a quick-mounting locking interface 11 with a dismounting time of ≤3 minutes, and double-channel sealing rings, with a total length of 1.8m, reduced by 40% compared with traditional bits.

[0048] Steel pipe concrete connecting sleeve (Figure 2): the inner wall trapezoidal thread clearance is ≤0.1mm, the sealing groove is adapted to 3 rubber rings, and the grouting hole is located at the center of the top end of the sleeve.

[0049] Integrated precast slab surface (Figure 3): C40 waterproof concrete (permeability resistance grade P8) is poured, the width of the joint after the butt joint of the tongue and groove joint is ≤1.5mm, and the fullness of the grouting hole after pressure grouting is ≥98%.

[0050] It should be noted that the innovative design of the present application includes the following: Compact piling drill bit 1 spatial adaptation design Three-dimensional size optimization: The drill bit as a whole adopts a combined structure of "tapered head + cylindrical drill body" (as shown in Figure 1), the head taper angle is 60°, the drill body diameter is reduced by 25% compared with the traditional drill bit (typical value is 500-700mm), the length is controlled within 1.5-2.0m, and the length-diameter ratio is ≤2.5:1, which ensures that it can rotate flexibly by 360° in a space with a clear height of 3.8m and a transverse width of 2.6m. Four spiral guide grooves 121 are arranged on the outer wall of the drill body, the groove depth is 25mm, and the spiral angle is 35°, which guides the mud to rise along the groove and is discharged, and the mud discharge efficiency is improved by 40% compared with the traditional smooth drill bit, avoiding the accumulation of mud in the limited space affecting the drilling speed.

[0051] Material and interface innovation: The drill bit head adopts YC15 tungsten-cobalt alloy (cobalt content 12%, hardness 91HRA), and the microstructure is uniformly distributed WC particles (particle size 3-5μm) and cobalt matrix, which can penetrate gravel layers or moderately weathered rock layers with a compressive strength of ≤80MPa. The drill bit and the drill rod are connected through a six-petal cam locking interface, a double-channel fluororubber O-ring (cross-sectional diameter 6mm, mud pressure resistance 1.5MPa) is arranged at the interface, the cam mechanism is driven by a rotating handle, and the disassembly or installation can be completed within 3 minutes, the connection torque is ≥800N・m, and the interface displacement is ≤0.3mm after 400kN axial load test, and there is no mud intrusion.

[0052] Composite reinforcing structure of steel pipe concrete connecting sleeve Mechanical locking thread system: The inner wall of the sleeve is processed with trapezoidal threads with a pitch of 2.5mm and a tooth type angle of 60°, the thread precision grade is 6H, the gap between the threads of the steel pipe outer wall 6g is ≤0.1mm, and the thread rotation length is ≥8 times the pitch (for example, when the steel pipe outer diameter is 426mm, the sleeve length is 852mm, and the thread rotation is 18 circles). The thread surface is treated by medium frequency quenching, the surface hardness is HRC45-50, the anti-slippage coefficient is ≥0.6, the shear strength is improved by 30% compared with the traditional welding connection, and the actual measured pull-out bearing capacity is ≥600kN (the traditional process is ≤400kN).

[0053] Multiple sealing and structural reinforcement: Three annular sealing grooves with a width of 10 mm and a depth of 8 mm are formed in the middle of the sleeve, and an ethylene-propylene-diene rubber sealing ring (Shore hardness 65A, aging resistance life ≥50 years) with a cross-sectional diameter of 8 mm is embedded, with the sealing ring lip facing the outside of the steel pipe, forming a "labyrinth" waterproof barrier. Eight radial reinforcing ribs with a thickness of 10 mm and a height of 50 mm are evenly welded on the outside of the sleeve, and the ribs and the sleeve are fully penetrated welded (welding seam height 10 mm). According to the finite element analysis, the stress concentration coefficient is reduced from 2.8 of the traditional sleeve to 1.2, the stress dispersion efficiency is improved by 55%, and the overall stiffness is improved by 40%.

[0054] Pressure grouting process: C60 micro-expansion grouting material (total amount of cementing material ≥500kg / m³, fluidity 350mm, 2 hour compressive strength 20MPa) is used, and the gap between the sleeve and the steel pipe is injected at a pressure of 0.4-0.6MPa through a top 25mm diameter grouting hole. The grouting material expels air and fills micro-pores under pressure, with a fullness of ≥98% measured, forming a "steel pipe-grouting material-sleeve" cooperative stress system with a standard deviation of compressive strength ≤1.5MPa, a 60% reduction in dispersion compared to traditional self-grouting.

[0055] Seamless connection technology of integrated prefabricated slab Factory prefabrication process optimization: The prefabricated slab is designed as a single block of 6m x 3m x 0.3m, and the reinforcement cage is optimally arranged through BIM modeling. The Φ14mm HRB400 reinforcement is spaced 150mm x 150mm, and straight-thread sleeve mechanical connection (joint grade I, tensile strength ≥540MPa) is used to form an overall stress grid. The concrete uses C40 waterproof concrete with 0.9kg / m³ polypropylene fiber mixed inside, with a permeability resistance grade of P8 and a slump of 180-200mm. The steam curing process is 60℃±5℃ constant temperature curing for 12 hours, with a slab flatness error of ≤3mm. Twelve Φ50mm grouting holes (arranged in a quincunx pattern with a hole spacing of 500mm and a position accuracy of ±2mm) are reserved.

[0056] On-site installation positioning system: The edge of the plate surface is provided with a 50mm wide convex and concave rabbet joint (convex part height 30mm, concave part depth 30mm), and during hoisting, Trimble S7 total station (accuracy ±2mm) and laser line projector are used for three-dimensional positioning, and the rabbet joint butt joint error is ≤1.5mm. The Φ20mm positioning steel bars (spacing 600mm) reserved on the plate surface are connected with the main structure reserved steel bars by using straight thread sleeve (tightening torque 200N·m), and C45 micro-expansion grouting material (pressure 0.3MPa) is injected through the grouting hole, and the grouting material strength reaches above 30MPa after 24 hours, the actual measurement of the splicing joint shear strength is ≥2.8MPa, and the leakage amount of the closed water test is ≤0.05L / (m·h).

[0057] 3.2.4 Limited space construction process cooperation Three-dimensional intersection operation planning: Piling operation and steel pipe prefabrication are carried out synchronously, the steel pipe with prefabricated thread is inserted immediately after the drill bit forms a hole, and the sleeve is temporarily positioned to reduce the idle time of the pile machine. After 12 hours of steel pipe grouting (strength reaches 75%), adjacent cross plate surface hoisting can be carried out, forming a three-dimensional intersection operation of “piling - steel pipe connection - plate surface installation”, which shortens the construction period by 30% compared with the traditional flow construction.

[0058] Key points of limited space operation: The pile machine is equipped with a 360° panoramic image monitoring system to monitor the distance between the drill bit and the surrounding structure in real time (accuracy ±50mm); the steel pipe connection adopts an electric torque wrench with angle compensation (accuracy ±3%) to adapt to the inclined operation when the clearance height is 3.5m; the plate surface hoisting adopts a five-axis linkage hydraulic hoist, which can realize ±10° inclined hoisting to avoid collision with the surrounding obstacles.

[0059] Comparison of key technical features In the traditional process, the piling drill bit relies on large size flange connection, the steel pipe connection mainly uses welding, and the plate surface is spliced in blocks without rabbet joint; through the design of “small size + fast interface + strong wear resistance” of the compact drill bit, the structure of “thread locking + multi-seal + pressure grouting” of the sleeve, and the system of “integrated prefabrication + rabbet butt joint + mechanical connection” of the plate surface, the construction problem under limited clearance is systematically solved, and the overall improvement of construction efficiency, structural performance and waterproof reliability is realized through the synergistic effect of various innovations.

[0060] The clearance height of a certain corridor project is 3.8m, a compact piling drill bit with a diameter of 600mm and a length of 1.5m is used, the steel pipe has an outer diameter of 325mm, the connecting sleeve has a length of 650mm (outer diameter 377mm), the prefabricated plate surface has a size of 6m×3m×0.25m, and the rabbet joint depth is 25mm.

[0061] Drill bit interface installation: 3-minute quick connection is achieved through the cam locking mechanism, the interface sealing ring is embedded to a depth of 4mm, and there is no leakage after a 0.8MPa water pressure test.

[0062] Sleeve thread connection: The steel pipe and sleeve threads are screwed together 18 turns, the tightening torque detected by the torque wrench is 1350N·m, and the reinforcing rib and sleeve are fully penetrated and welded (weld height 10mm).

[0063] Tongue-and-groove joints on the board surface: Use a laser line projector to adjust the board surface position, the tongue-and-groove joint gap is ≤1.5mm, the tightening torque of the positioning steel bar straight thread sleeve is 200N·m, and the grouting fullness is tested 24 hours after grouting to be ≥98%.

[0064] Structural performance testing showed that when an axial load of 400kN was applied to the drill bit interface, the displacement was ≤0.3mm, and there was no mud intrusion; the sleeve pull-out test was loaded to 600kN without damage, and the rubber ring showed no aging cracking after 500 water pressure cycle tests; the board surface closed water test (water depth 50mm, 48 hours) showed a leakage of ≤0.05L / (m・h), meeting the GB50208-2011 Class I waterproofing standard.

[0065] In summary, the present invention has the following beneficial effects: 1. Construction efficiency is significantly improved Compact drill bit for spatial adaptability The overall size of the piling drill bit is 20%-30% smaller than traditional methods, with an aspect ratio of ≤2.5:1. It can maneuver flexibly in narrow spaces with a headroom of ≤4m and a lateral width of ≤2.6m, avoiding collisions with surrounding structures. The quick-install and quick-release interface (mechanical locking mechanism) reduces drill bit replacement time from several hours with traditional methods to under 5 minutes, reducing single-pile drilling time by 50% and increasing daily piling output by 100%.

[0066] Efficiency of prefabrication and assembly processes The integrated prefabricated panels are cast in their entirety in the factory and quickly hoisted on-site using a laser positioning system (accuracy ±2mm). The installation time for a single 6m×3m panel is only 30% of that of the traditional block-joining process (a single 2m×2m panel requires nine pieces), shortening the overall construction period by more than 40%.

[0067] 2. Structural connection strength and stability are significantly enhanced Mechanical locking of high-precision threaded sleeves The steel pipe and the sleeve are matched by trapezoidal thread with a pitch of 2-3 mm and a tooth angle of 60°, the tightening torque is greater than or equal to 1200 N·m, the external radial reinforcing rib plate (thickness 8-12 mm) makes the connection uplift bearing capacity increase by more than 30% (actual measurement is greater than or equal to 600 kN, and the traditional welding process is less than or equal to 400 kN), and the ultrasonic testing weld joint qualified rate is 100%.

[0068] Compactness of pressure grouting The high-strength grouting material (28-day compressive strength greater than or equal to 60 MPa) is filled in the sleeve under a pressure of 0.3-0.6 MPa, the filling fullness is greater than or equal to 98%, a steel pipe-grouting material-sleeve cooperative stress system is formed, the structural integrity is improved, the standard deviation of compressive strength is less than or equal to 2 MPa, and the dispersion is reduced by 60% compared with the traditional self-weight grouting.

[0069] III. Water resistance and durability are greatly optimized Reliability of multi-seal system Three sealing rubber rings (EPDM, cross-sectional diameter 8 mm) are arranged between the connection sleeve and the steel pipe, cooperating with the sealing groove structure, and no leakage is found under 0.5 MPa water pressure test, the water resistance reaches IP67 standard, and the leakage rate is reduced from 15%-20% of the traditional process to less than or equal to 1%.

[0070] Seamless splicing of integrated slab The prefabricated slab edge is provided with a rabbet joint (depth 30 mm), and the whole connection is formed by pressure grouting (grouting material strength C45) on site, the splicing joint width is less than or equal to 1.5 mm, the water leakage amount of the closed water test is less than or equal to 0.05 L / (m·h), the impermeability grade reaches P8, and the water resistance is improved by 93% compared with the traditional block installation.

[0071] IV. Construction operation difficulty and labor intensity are reduced Reduce high-altitude welding operation The new connection sleeve does not need to be welded on site, reducing 80% of the high-altitude operation amount, avoiding welding smoke hazards in limited space, and significantly improving construction safety.

[0072] Convenience of modular construction Standardized components are used in each process of piling, steel pipe connection, and slab installation, the operation process is simplified, the construction personnel are reduced by 30%, the labor intensity is reduced from level III (heavy labor) to level II (moderate labor), and the man-machine engineering demand in limited space is adapted.

[0073] V. Comprehensive economic benefits are improved Construction period cost: construction period is shortened by more than 40%, and mechanical rental and labor cost is reduced by 30%-40%; Maintenance cost: waterproof performance is improved, so that the leakage maintenance cost is reduced by more than 80% in later period, and the service life of the structure is prolonged by more than 10 years; Environmental benefits: reduce on-site wet work and construction waste, meet the requirements of green construction.

[0074] The technical solutions provided by the embodiments of the present application are described in detail above, specific examples are applied in this paper to describe the principles and implementation manners of the embodiments of the present application, and the above description of the embodiments is only applicable to help understand the principles of the embodiments of the present application; meanwhile, for the general technical personnel in the art, according to the embodiments of the present application, the specific implementation manners and application ranges will be changed, and the above description should not be understood as the limitation of the present application.

Claims

1. A method for constructing a corridor with limited clearance, characterized in that: The following steps are involved: Step S1: Using a compact piling drill bit that is 20%-30% shorter and smaller in diameter than a conventional drill bit, and connecting it to the drill pipe via a quick-install / quick-release interface, wherein the quick-install / quick-release interface is a mechanical locking structure; Step S2: A connecting sleeve with a high-precision threaded inner wall is installed at the joint of the corridor steel pipes, multiple sealing rubber rings are arranged between the sleeve and the steel pipe, and the interior of the sleeve is filled with grouting material; Step S3: connect the prefabricated integrated panel surface in the factory with the reserved steel bars of the main structure through the reserved positioning steel bars of the panel surface, and use the pressure grouting process to reinforce the connection.

2. The method for constructing a lower corridor with limited clearance according to claim 1, characterized in that: The head of the compact pile driving drill bit is made of tungsten-cobalt alloy; a sealing structure is provided at the connection interface between the compact pile driving drill bit and the drill rod, and the sealing structure includes a rubber sealing ring embedded in the interface gap.

3. The method for constructing a lower corridor with limited clearance according to claim 1, characterized in that: The inner wall thread of the connecting sleeve matches the pitch and tooth angle of the outer wall thread of the steel pipe, and radially distributed reinforcing ribs are arranged on the outside of the sleeve. The thickness of the reinforcing ribs is 8-12mm and the spacing is ≤100mm.

4. The method for constructing a lower corridor with limited clearance according to claim 1, characterized in that: The integrated prefabricated panel is formed into an integral steel frame when cast in the factory, and a grouting channel with a diameter of 50mm is reserved on the panel, and the channel position accuracy is ±2mm.

5. A device for the construction method according to any one of claims 1 to 4, characterized in that: include: Compact piling drill bit, including a drill head made of tungsten-cobalt alloy, a quick-install and quick-release mechanical locking interface and double-pass O-ring seals, and an overall length-to-diameter ratio of ≤2.5:1; The steel tube concrete connection sleeve has a trapezoidal thread with a pitch of 2-3mm and a tooth angle of 60° on the inner wall. The sleeve has a sealing groove with a width of 10mm and a depth of 8mm, and a radial reinforcement rib with a thickness of 8-12mm on the outside. The integrated prefabricated panel has a 30mm deep tongue-and-groove seam at the edge of the panel. The internal steel reinforcement skeleton is formed into a whole by mechanical connection or welding. The panel surface is reserved with 20mm diameter positioning steel bars and 50mm diameter grouting holes.

6. The device according to claim 5, characterized in that The quick-install and quick-release mechanical locking interface includes a cam locking mechanism and an anti-loosening and anti-retraction ring, and the interface matching clearance is ≤0.1mm.

7. The device according to claim 5, characterized in that The sealing rubber ring is made of EPDM rubber, has a cross-sectional diameter of 8 mm, and is installed in the sealing groove between the sleeve and the steel pipe.

8. The device according to claim 5, characterized in that The connecting sleeve is made of Q345B steel, and its length is 1.5-2 times the outer diameter of the steel pipe. The grouting hole is set at the center of the top of the sleeve and has a diameter of 25mm.

9. The device according to claim 5, characterized in that The integrated prefabricated panel surface is cast with C40 waterproof concrete, with a water-resistance grade of ≥P8, and the steel skeleton is HRB400 steel bars with a spacing of 150mm×150mm.

10. The device according to claim 5, characterized in that The tongue-and-groove joint of the prefabricated panel is a convex-concave matching structure, the tongue-and-groove width is 50mm, and the overlapping length of the positioning steel bars is ≥300mm.

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