Well lid assembly system for multiple heavy vehicle road sections and construction method thereof

Abstract

The invention provides a multi-heavy vehicle road section assembly well lid system and a construction method thereof, and relates to the field of well lid construction.The multi-heavy vehicle road section assembly well lid system comprises a shaft and a prefabricated well lid structure arranged above the shaft, and the prefabricated well lid structure comprises a well lid plate installed on a prefabricated steel structure; at least two prefabricated steel pipe structures are arranged between the prefabricated steel structure and the shaft, and the prefabricated steel pipe structures are obliquely arranged in a soil layer. The prefabricated steel pipe structure is obliquely arranged between the prefabricated steel structure and the shaft and is matched with the V-shaped steel strip structure with the expandable end, so that the vertical and horizontal contact area with a soil layer is greatly increased, the load of a well lid system can be dispersed to the peripheral soil layer through the prefabricated steel pipe structure, and multi-stage bearing is achieved; the vertical load and the horizontal impact force brought by multiple heavy vehicles are effectively resisted, the problems of sedimentation, displacement, edge warping and the like of the well lid are avoided, and the structural stability is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of manhole cover construction, and more specifically, to a manhole cover assembly system and construction method for heavy vehicle road sections. Background Technology

[0002] Although manhole covers and their shafts are considered ancillary structures of municipal facilities, they have a significant impact on road and drainage engineering. Due to the repeated action of vehicle loads, manhole covers, shafts, and surrounding road surfaces often suffer from subsidence, damage, and potholes, severely affecting driving comfort and safety. Vehicles generate substantial impact loads when passing over them, leading to vehicle wear and accelerated damage to the surrounding road surface. In my country, manhole covers and shafts are mostly made of brick or concrete, and the materials of the manhole body differ significantly from the surrounding soil and road surface materials. Under repeated traffic loads, the manhole covers and shafts experience uneven settlement with the surrounding soil, and this settlement is often much greater than that of the surrounding road surface.

[0003] In addition to vertical loads, the loads from moving vehicles also exert horizontal loads on manhole covers. Horizontal loads can easily cause cracks and deformation around the manhole, which can lead to larger problems such as subsequent collapses. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a manhole cover system and its construction method for heavy-duty vehicle road sections, aiming to improve the problems of existing manhole covers for heavy-duty vehicle road sections being prone to settlement, displacement, insufficient load-bearing capacity, cumbersome construction and maintenance, and significant impact on traffic.

[0005] This invention is implemented as follows: This invention provides a multi-heavy vehicle road section assembly manhole cover system, including a manhole shaft and a prefabricated manhole cover structure disposed above the manhole shaft. The prefabricated manhole cover structure includes a manhole cover plate installed on a prefabricated steel structure. At least two prefabricated steel pipe structures are disposed between the prefabricated steel structure and the manhole shaft. The prefabricated steel pipe structures are inclinedly disposed within the soil layer, and the ends of the prefabricated steel pipe structures are provided with outwardly extending steel bar structures. The steel bar structures increase the vertical and horizontal contact area between the prefabricated steel pipe structures and the soil layer, thereby improving the connection strength and anti-displacement ability of the prefabricated steel pipe structures and the soil layer.

[0006] Furthermore, the end of the precast steel pipe structure is provided with a cone head, which can reduce the resistance when the precast steel pipe structure is drilled into the soil, facilitate quick positioning and installation, and enhance the impact resistance of the end structure.

[0007] Furthermore, the steel bar structure consists of two steel bars forming a V-shape, with one end of the two steel bars rotatably connected and the other end rotatably connected to a sliding annular component. When the V-shaped steel bars are unfolded, they can evenly distribute the load, and compared to a single steel bar, they can more efficiently increase the contact area with the soil layer and the synergistic bearing effect. The rotatable connection method allows for flexible adjustment of the steel bar angle.

[0008] Furthermore, the prefabricated steel pipe structure also includes solid steel rods, which are fixed and coaxially arranged with the cone head. The sliding annular component is slidably sleeved on the solid steel rods. By linearly moving the sliding annular component along the solid steel rods, the angle of the V-shaped structure after the steel bar structure is unfolded can be adjusted. The unfolding angle of the steel bars can be flexibly adjusted according to soil characteristics such as density and bearing capacity to adapt to different geological conditions and ensure optimal load-bearing effect.

[0009] Furthermore, an outer steel pipe is detachably connected to one end of the cone near the solid steel rod. When the outer steel pipe is installed on the cone, the steel bar structure is housed within the outer steel pipe, preventing interference between the steel bar and the soil when the prefabricated steel pipe structure drills into the soil layer, ensuring a smooth drilling process. When the outer steel pipe detaches from the cone, the angle at which the steel bar structure unfolds into the soil layer is adjusted by moving the sliding annular component, achieving reliable contact between the steel bar and the soil layer. The outer steel pipe and the cone can be connected by threads or snap-fit ​​connections, ensuring convenient disassembly and sealing during installation.

[0010] Furthermore, an inner steel pipe is installed on the sliding annular component at the end furthest from the cone. One end of the inner steel pipe is open, and the other end is sealed and fixed to the sliding annular component. A prefabricated steel sleeve is installed at the open end of the inner steel pipe. The prefabricated steel sleeve includes a grouting port and a mating port. The inner diameter of the mating port is the same as the inner diameter of the open end of the inner steel pipe, ensuring smooth filling of concrete grout. The grouting port is vertically upward, so that after the concrete grout is injected from the grouting port, it fills the mating port and the inner steel pipe under the action of gravity until the inner steel pipe and the prefabricated steel sleeve are filled with concrete grout. After the concrete has cured, the inner steel pipe, the prefabricated steel sleeve, the solid steel rod, and the sliding annular component can form an integral structure, further enhancing the rigidity and load-bearing capacity of the prefabricated steel pipe structure, while achieving a reliable connection with the prefabricated steel structure.

[0011] Furthermore, the outer wall of the inner steel pipe is provided with an external protrusion to increase the contact area. The external protrusion can be an annular boss, a spiral ridge, or an irregular protrusion structure, which can significantly improve the friction between the inner steel pipe and the surrounding concrete and soil layers, prevent the inner steel pipe from shifting axially or radially, and enhance the structural stability.

[0012] Furthermore, the end of the precast steel structure is provided with a positioning protrusion that can be inserted into the grouting port. The positioning protrusion can achieve precise positioning of the precast steel structure and the precast steel sleeve, ensuring that the manhole cover structure is installed flat. At the same time, after the concrete grout has solidified, the positioning protrusion and the precast steel sleeve form an integrated connection, so that the load of the manhole cover structure can be transferred to the precast steel pipe structure through the precast steel sleeve and the inner steel pipe, and then dispersed to the surrounding soil layer, realizing multi-level transfer and dispersion of load.

[0013] This invention also provides a construction method for assembling manhole covers in road sections with multiple heavy vehicles. The method, applying the aforementioned manhole cover assembly system for road sections with multiple heavy vehicles, includes the following steps: S1. Load and Geological Parameter Calculation: Based on the maximum horizontal force exerted on the manhole cover by the maximum weight of the vehicle obtained from daily monitoring and statistics, the load is proportionally converted into the horizontal load borne by a single precast steel pipe structure. Then, the foundation bearing capacity value, soil layer distribution information, and soil mechanical parameters such as internal friction angle and cohesion of the corresponding depth of the soil layer in the geological exploration report are consulted. Through mechanical calculation, the depth and position of the end of the precast steel pipe structure drilled into the soil layer are determined to ensure that the precast steel pipe structure can provide sufficient load resistance and adapt to the site geological conditions. S2. Preparation of precast components: All components such as manhole covers, precast steel structures, precast steel pipe structures, outer steel pipes, and precast steel sleeves are precast in the factory. At the same time, self-compacting quick-setting concrete is pre-mixed to ensure that the fluidity, strength and setting speed of the concrete meet the construction requirements. After all components and materials pass the quality inspection, they are transported to the construction site for use, realizing full precast assembly and ensuring the consistency of structural quality. S3. Removal of old manhole covers and excavation of foundation pit: At the construction site, the original old manhole covers and surrounding damaged structures are first removed. A circular pit is dug around the original vertical shaft. The depth and width of the circular pit are determined according to the installation angle and length of the prefabricated steel pipe structure to ensure sufficient construction space is reserved, while avoiding excessive excavation that could damage the surrounding road structure. S4. Installation of precast steel pipe structure: Along the driving direction, on both sides of the middle and the upper and lower middle sides of the ring pit, the precast steel pipe structure is drilled in by rotating the special equipment. During the drilling process, the cone head is used to reduce the resistance and ensure that the precast steel pipe structure is in place at the preset angle and depth. The inclined precast steel pipe structure can bear vertical load and horizontal load at the same time, improving the overall impact resistance. S5. Removal of outer steel pipe: After the precast steel pipe structure is in place, twist open and pull out the outer steel pipe in the precast steel pipe structure to release the steel bar structure from constraints and prepare for the subsequent deployment of steel bars. S6. Steel bar structure unfolding: Using a special tool, the inner steel pipe in the prefabricated steel pipe structure is pressed down, which drives the sliding ring component to move along the solid steel rod towards the cone head, so that the steel bar structure at the lower end of the prefabricated steel pipe structure is fully opened, and adjusted to the preset angle according to the soil characteristics to ensure that the steel bar structure is in close contact with the soil and increase the contact area. S7. Concrete grouting and curing: A precast steel sleeve is installed on the upper part of the precast steel pipe structure so that the joint of the precast steel sleeve is precisely connected with the opening end of the inner steel pipe. Then, premixed self-compacting quick-setting concrete is injected into the grouting port of the precast steel sleeve. Under the action of gravity, the concrete fills the gaps inside the inner steel pipe, the precast steel sleeve and the surrounding area. After the concrete cures, an integrated load-bearing structure is formed. S8. Manhole cover structure installation: After the concrete reaches the preset strength, the precast manhole cover structure is installed, so that the positioning protrusion of the precast steel structure is fully inserted into the grouting port of the precast steel sleeve to achieve precise positioning and fixation of the manhole cover structure, ensuring that the manhole cover is flush with the road surface and ensuring smooth traffic. S9. Road surface restoration: Fill the circular pit with a layer of self-compacting quick-setting concrete and an asphalt layer in sequence, and compact them in layers. Fill the reserved area near the manhole cover with high-elasticity plastic track material. This material can buffer the impact force when vehicles run over the edge of the manhole cover and reduce the settlement difference between the manhole cover and the surrounding road surface. After completion, the road surface is compacted as a whole to restore the road surface traffic conditions.

[0014] The beneficial effects of this invention are: 1. Significantly improved load-bearing capacity and stability: By setting the precast steel pipe structure at an angle between the precast steel structure and the manhole, and combining it with the V-shaped steel bar structure that can be unfolded at the end, the vertical and horizontal contact area with the soil layer is greatly increased. This allows the load of the manhole cover system to be distributed to the surrounding soil layer through the precast steel pipe structure, achieving multi-level load-bearing capacity. It effectively resists the vertical load and horizontal impact force brought by multiple heavy vehicles, avoiding problems such as manhole cover settlement, displacement, and warping, and greatly improving structural stability.

[0015] 2. High adaptability, suitable for different geological conditions: The unfolding angle of the steel bar structure can be flexibly adjusted by sliding ring components. Combined with the load and geological parameter calculations before construction, the structural parameters can be optimized according to the density and bearing capacity characteristics of different soil layers, ensuring that the optimal load-bearing effect can be achieved under various geological conditions, and the application range is wide.

[0016] 3. Prefabricated construction, high efficiency and minimal impact on traffic: All components are prefabricated in the factory. On-site work only requires dismantling, drilling, assembly, grouting, and road restoration. The construction process is simple and the cycle is short. Compared with the traditional on-site casting method, it can significantly shorten the time occupied by the road and reduce the interference with road traffic. At the same time, the quality of prefabricated components is controllable, the structural consistency is good, and the construction quality is easier to guarantee.

[0017] 4. Convenient maintenance and low cost: If the manhole cover needs to be repaired or replaced later, only the surrounding asphalt layer and surface concrete need to be removed, and the connection between the precast steel structure and the precast steel sleeve needs to be separated. The manhole cover or damaged components can then be replaced without large-scale excavation. This results in high maintenance efficiency, significantly reducing maintenance costs and secondary impact on traffic.

[0018] 5. Reasonable structural design and long service life: The outer protrusion of the inner steel pipe increases the friction with concrete and soil, the positioning protrusion enables precise installation of the manhole cover, the high elasticity plastic material buffers the edge impact, and the multiple structural optimizations work together to effectively reduce component wear and structural damage, and extend the service life of the manhole cover system.

[0019] This invention patent primarily aims to enhance the horizontal force resistance and vertical load-bearing capacity of manhole covers, thereby improving their ability to prevent uneven settlement and resist deformation of the surrounding road surface in complex environments, effectively improving the comfort and safety of the road surface at the manhole cover location. The device of this invention patent employs a combination of factory prefabrication of some structures and rapid on-site construction of others. These two components can be quickly and securely assembled on-site. The prefabricated manhole cover structure simply requires the insertion of a prefabricated steel sleeve on-site, greatly improving installation convenience and effectively enhancing overall construction efficiency and the structural performance of the manhole cover. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the multi-heavy vehicle road section assembly manhole cover system provided by an embodiment of the present invention; Figure 2 This is a schematic diagram of a precast steel pipe structure; Figure 3 This is a schematic diagram of the unfolded state of the steel bar structure in a precast steel pipe structure; Figure 4 This is a schematic diagram of a prefabricated steel sleeve structure; Figure 5 This is a structural diagram of the manhole cover and prefabricated steel structure; Figure 6 This is a structural schematic diagram of a prefabricated steel structure; Figure 7 This is a schematic diagram illustrating the calculation principle after the prefabricated steel pipe structure is installed.

[0022] In the diagram: 1. Well shaft; 2. Well cover plate; 3. Precast steel structure; 4. Precast steel pipe structure; 40. Steel bar structure; 41. Conical head; 42. Sliding ring component; 43. Solid steel rod; 44. Outer steel pipe; 45. Inner steel pipe; 46. Precast steel sleeve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example like Figures 1-7 As shown, this embodiment provides a multi-heavy vehicle road section assembly manhole cover system, including a manhole cylinder 1 and a prefabricated manhole cover structure set above the manhole cylinder 1. The prefabricated manhole cover structure includes a manhole cover plate 2 and a prefabricated steel structure 3. The manhole cover plate 2 is prefabricated from high-strength reinforced concrete, preferably with a thickness of 150mm and an anti-slip texture on the surface. The prefabricated steel structure 3 is a ring frame structure, welded from Q355B steel. The manhole cover plate 2 is fixed to the prefabricated steel structure 3 with bolts to ensure a firm connection.

[0025] To address the issue of horizontal loads in addition to vertical loads during manhole cover use, this embodiment incorporates four prefabricated steel pipe structures 4 evenly distributed between the prefabricated steel structure 3 and the manhole casing 1. These four prefabricated steel pipe structures 4 are symmetrically inclined, allowing them to simultaneously withstand both vertical and horizontal loads, thus enhancing impact resistance. The inclination angle was determined through subsequent calculations and verification based on actual conditions. The ends of the prefabricated steel pipe structures 4 are equipped with conical heads 41 made of alloy steel with a hardened surface treatment, which reduces resistance during drilling into the soil and enhances the wear resistance of the ends.

[0026] Reference Figure 1 , Figure 2 and Figure 3 The precast steel pipe structure 4 includes a steel bar structure 40, a cone head 41, a sliding ring component 42, a solid steel rod 43, an outer steel pipe 44, an inner steel pipe 45, and a precast steel sleeve 46.

[0027] In other embodiments, to further enhance the compressive strength of the precast steel pipe structure 4 within the soil layer, the contact area can be increased. Preferably, the ends of the precast steel pipe structure (4) are provided with outwardly extending steel bar structures (40). The steel bar structure 40 consists of two high-strength steel bars forming a V-shaped structure. One end of the two steel bars is rotatably connected by a pivot, and the other end is rotatably connected to a sliding annular member 42 by a pivot. The sliding annular member 42 is made of stainless steel, and its inner diameter is adapted to the outer diameter of the solid steel rod 43, allowing it to slide smoothly along the solid steel rod 43. The solid steel rod 43 is made of No. 45 steel. One end of the solid steel rod 43 is welded and fixed to the cone head 41, and the two are coaxially arranged to ensure uniform stress distribution.

[0028] Furthermore, the cone 41 has an external thread at one end near the solid steel rod 43, and the outer steel tube 44 has an internal thread at one end. The outer steel tube 44 and the cone 41 are detachably connected by the thread. When the outer steel tube 44 is installed on the cone 41, the steel bar structure 40 can be completely housed inside the outer steel tube 44 to avoid interference when drilling into the soil. After removing the outer steel tube 44, the steel bar structure 40 can be unfolded by pushing the sliding annular component 42. The unfolding angle can be adjusted between 30° and 90° to adapt to different soil conditions.

[0029] The inner steel pipe 45 is made of seamless steel pipe. One end of the inner steel pipe 45 is open, and the other end is welded and sealed to the sliding annular member 42. The outer wall of the inner steel pipe 45 is provided with annular protrusions distributed at intervals, which can increase the friction with concrete and soil.

[0030] Reference Figure 1 and Figure 4 The precast steel sleeve 46 is made of Q235 steel and has a two-way structure, including a grouting port and a mating port. It is interference-fitted with the open end of the inner steel pipe 45. The grouting port is vertically upward to facilitate the injection of concrete grout.

[0031] The bottom of the precast steel structure 3 corresponds to the position of the precast steel sleeve 46 and is provided with 4 positioning protrusions. The positioning protrusions are cylindrical structures. During installation, the positioning protrusions are inserted into the grouting port of the precast steel sleeve 46 to achieve precise positioning. After the concrete cures, an integrated connection is formed.

[0032] This embodiment also provides a construction method for the manhole cover system, the specific steps of which are as follows: S1. Load and geological parameter calculation: Based on the maximum horizontal force exerted by the maximum weight of the vehicle on the manhole cover obtained from daily monitoring and statistics, the load is proportionally converted into the horizontal load borne by a single precast steel pipe structure 4. Then, the foundation bearing capacity value of the soil at the depth of the construction soil layer and the distribution information and soil mechanics parameters of the soil layer above the depth are checked in the geological survey report to determine the depth and position of the end of the precast steel pipe structure 4 drilled into the soil layer.

[0033] In step S1, the drilling length and end resistance of a single precast steel pipe are determined, and the frictional resistance is calculated by the bearing capacity of the precast steel pipe structure 4. The resistance provided by the end of the precast steel pipe structure 4 is the sum of the end resistance and the frictional resistance. Then, the resistance value provided by the end of the precast steel pipe structure 4 is corrected by indoor test, and the precast parameters of each component in the factory precast steel pipe structure 4 are obtained.

[0034] The process for determining the bearing capacity of a single precast steel pipe is as follows: Reference Figure 7 The angle between the lateral earth pressure on the precast steel pipe and the peripheral skin friction is the interface friction angle δ. According to the method for calculating at-rest earth pressure, the expression for the lateral earth stress q(θ) of the precast steel pipe is: cosβ; In the formula: Ks(θ) is the lateral earth pressure coefficient of the precast steel pipe; θ is the central angle of the section perpendicular to the axis of the precast steel pipe; γ is the unit weight of the soil layer; z is the vertical depth of the precast steel pipe, for inclined precast steel pipes, z = zcosβ; h is the axial length of the precast steel pipe; β is the inclination angle of the precast steel pipe. The formula for calculating the average shear stress around the perimeter of the precast steel pipe is: ; In the formula, τ(θ) is the average shear stress around the precast steel pipe; δ is the interface friction angle.

[0035] From the above formula, the total frictional resistance around the precast steel pipe can be calculated using the following formula: ; In the formula, A is the circumference of the prefabricated steel pipe; Because the earth pressure on the precast steel pipe is unevenly distributed, the upper earth pressure is divided into four equal regions, resulting in: (1) The lateral earth pressure coefficient of the precast steel pipe with an inclination angle β=0 is Ks(θ)1=0.25Ks2+0.25Ks4, where Ks2=Ks4, then Ks(θ)1=0.5Ks2,4; (2) The lateral earth pressure coefficient of the precast steel pipe with an inclination angle β=+β, Ks(θ)2=0.25Ks3; (3) The lateral earth pressure coefficient for the precast steel pipe with an inclination angle β=-β, Ks(θ)3=0.25Ks1 Ks(θ)=Ks(θ)1+Ks(θ)2+Ks(θ)3=0.5Ks2,4+0.25Ks3+0.25Ks1 Ks2,4,Ks3,Ks1 are unknown values, and are solved using the following method: Considering the friction angle ratio ( (Including soil friction angle), precast steel pipe diameter D, precast steel pipe inclination angle β, length h, and aspect ratio. The effects of the superload Q and self-weight G were investigated. Numerical simulation software was used to simulate the above parameters under various working conditions, and calculations were performed for a large number of working conditions. Finally, the results were obtained through... The +g multiple linear regression equation is used to fit the relevant mathematical relationship. The correlation coefficient is calculated to be above 0.9 by calculating the number of operating conditions. Specifically: + ; + ; + ; In the formula, , , , , , , , , , , , , , , , , , , , , All coefficients are obtained from simulation calculations; D, h, β, G, All parameters are controllable. φ is the internal friction angle of the soil, which can be found in the geological survey report of the project area. The upper axial ultimate bearing capacity Q is defined as the load D that causes a displacement of 0.05D at the top of the pipe, where D is the diameter.

[0036] The total frictional resistance around the precast steel pipe is: The calculation process for determining the end resistance is as follows: The end resistance can be found in the geological survey report as the bearing capacity value of the foundation soil at a certain depth. The end of the prefabricated steel pipe drilled into the soil in this invention is controlled at the soil layer position, and is found to be Fd value in kPa.

[0037] The resistance provided by the end is the end resistance plus the frictional resistance: ; The frictional resistance f at the end was obtained through an indoor pull-out test.

[0038] The axial depth control below the upper control line of the end is hd, assuming that the upper load of the end is passed through the peripheral friction of the end at an angle. The pressure diffuses to the end, forming a uniformly compressed circular surface A. d Furthermore, the area is reduced according to the ratio of the area to the area of ​​the circle, with a reduction factor of k.

[0039] ; In the formula, A d The end face of the pressure circle is considered to account for the diffusion angle; Dd is the diameter of the end face. The internal friction angle of the soil around the end is denoted as .

[0040] Then the resistance is ; In summary, the total load-bearing capacity W provided by the precast steel pipe is: The provided horizontal bearing capacity Ws and vertical bearing capacity Wh are respectively: ; ; According to the bearing capacity test method of the standard "DBJ / T 15-60-2019 Code for Testing Building Foundations", multiple indoor vertical bearing capacity tests were conducted on the precast steel pipe after molding according to this invention patent to measure its vertical bearing capacity. Then, the above formula was modified, and then: S2. Preparation of precast components: Precast manhole cover slabs 2, precast steel structures 3, precast steel pipe structures 4, outer steel pipes 44, precast steel sleeves 46, etc. in the factory. Premix self-compacting quick-setting concrete with a concrete strength grade of C60. The initial setting time is controlled within 2 hours and the final setting time is controlled within 6 hours. After the components pass the compressive and shear strength tests, they are transported to the construction site using special transport vehicles to avoid damage to the components during transportation.

[0041] S3. Removal of old manhole covers and excavation of foundation pit: Remove the original old manhole covers and the surrounding damaged road surface structure, dig a circular pit around the original vertical shaft, use steel sheet piles for support during the excavation process to prevent the foundation pit from collapsing, and clean up debris and loose soil in the pit at the same time.

[0042] S4. Installation of precast steel pipe structure: Using a small rotary drilling rig, along the driving direction, four precast steel pipe structures are drilled into the soil layer at a preset angle to the vertical direction on both sides of the middle and the upper and lower middle sides of the ring pit. The depth and angle are monitored in real time during the drilling process to ensure that the ends accurately reach the silty clay layer underground.

[0043] S5. Removal of outer steel pipe: Use a wrench to unscrew the threaded connection between the outer steel pipe 44 and the cone head 41, pull the outer steel pipe 44 out of the soil, and place it in a designated area for later use.

[0044] S6. Steel bar structure unfolding: Hydraulic jacks are used to press the inner steel pipe 45 down, driving the sliding ring component 42 to move along the solid steel rod 43 towards the cone head 41, making close contact with the silty clay layer. The unfolding angle is measured with a tape measure to ensure that it meets the design requirements.

[0045] S7. Concrete grouting and curing: Precisely connect the interface of the precast steel sleeve 46 with the opening end of the inner steel pipe 45, fix the precast steel sleeve 46 with hoisting equipment, and then inject the premixed self-compacting quick-setting concrete from the grouting port through the grouting pump until the concrete overflows from the grouting port, indicating that the inner steel pipe 45 and the precast steel sleeve 46 have been completely filled. Let it stand for 4 hours to cure until the concrete reaches 70% of the design strength.

[0046] S8. Manhole cover structure installation: Hoist the precast manhole cover structure to the designated position, so that the positioning protrusion at the bottom of the precast steel structure 3 is fully inserted into the grouting port of the precast steel sleeve 46. Adjust the position of the manhole cover to ensure that the manhole cover is flush with the surrounding road surface with an error of no more than 2mm. Then tighten the fixing bolts between the manhole cover plate 2 and the precast steel structure 3.

[0047] S9. Road surface restoration: Fill the circular pit with a 500mm thick layer of self-compacting quick-setting concrete and a 50mm thick layer of asphalt. Each layer is compacted with a small road roller to a compaction degree of not less than 96%. Within 500mm of the edge of the manhole cover, fill with a 20mm thick layer of high-elasticity plastic track material. Finally, the entire road surface is rolled and leveled. After 24 hours of curing, the road can be opened to traffic.

[0048] The manhole cover system in this embodiment has been verified through actual use. Under the condition of frequent passage of multiple heavy vehicles, there is no settlement or displacement, the load-bearing capacity is stable, and the construction cycle is only 3 days, which is 7 days shorter than the traditional construction method. It is also convenient to maintain and has significant economic and social benefits.

[0049] It should be noted that the specific model and specifications of the motor need to be selected and determined based on the actual specifications of the device. The specific selection and calculation method adopts the existing technology in this field, so it will not be elaborated in detail.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A manhole cover system for heavy-duty vehicle road sections, comprising a manhole casing and a prefabricated manhole cover structure disposed above the manhole casing, wherein the prefabricated manhole cover structure includes a manhole cover plate installed on a prefabricated steel structure, characterized in that, At least two precast steel pipe structures are provided between the precast steel structure and the well shaft. The precast steel pipe structures are inclined within the soil layer, and the ends of the precast steel pipe structures are provided with outwardly extending steel bar structures. The steel bar structures increase the vertical and horizontal contact area between the precast steel pipe structures and the soil layer.

2. The multi-heavy-vehicle road section manhole cover system according to claim 1, characterized in that, The precast steel pipe structure is provided with a cone at its end.

3. The multi-heavy-vehicle road section manhole cover system according to claim 2, characterized in that, The steel bar structure consists of two steel bars forming a V-shaped structure, with one end of the two steel bars rotatably connected and the other end rotating on a sliding annular component.

4. The multi-heavy-vehicle road section manhole cover system according to claim 3, characterized in that, The precast steel pipe structure also includes solid steel rods, which are fixed and coaxially arranged with the cone head, and the sliding annular component is slidably sleeved on the solid steel rods; The angle of the V-shaped structure after the steel bar structure is unfolded can be adjusted by the linear movement of the sliding annular component along the solid steel rod.

5. The multi-heavy-vehicle road section manhole cover system according to claim 4, characterized in that, The cone head is detachably connected to an outer steel pipe at one end near the solid steel rod. When the outer steel pipe is installed on the cone head, the steel bar structure is located inside the outer steel pipe, which is used for the prefabricated steel pipe structure to move into the soil layer; When the outer steel pipe detaches from the cone head, the angle at which the steel bar structure expands into the soil layer is adjusted by moving the sliding annular component.

6. The multi-heavy-vehicle road section manhole cover system according to claim 5, characterized in that, An inner steel tube is installed on the sliding annular component at the end away from the cone head. One end of the inner steel tube is open, and the other end is sealed and fixed to the sliding annular component. A prefabricated steel sleeve is installed at the open end of the inner steel pipe. The prefabricated steel sleeve includes a grouting port and a connecting port. The inner diameter of the connecting port is the same as the inner diameter of the open end of the inner steel pipe. The grouting port is vertically upward, so that after the concrete grout is injected from the grouting port, it fills the connecting port and the inner steel pipe under the action of gravity until the inner steel pipe and the prefabricated steel sleeve are filled with concrete grout.

7. The multi-heavy-vehicle road section manhole cover system according to claim 6, characterized in that, The outer wall of the inner steel pipe is provided with an external protrusion to increase the contact area.

8. The multi-heavy-vehicle road section manhole cover system according to claim 7, characterized in that, The precast steel structure has a positioning protrusion at its end that can be inserted into the grouting port.

9. A construction method for installing manhole covers on road sections with heavy vehicles, characterized in that, The application of the multi-heavy vehicle road section assembly manhole cover system as described in claim 8 includes the following steps: S1. Based on the maximum horizontal force exerted on the manhole cover by the maximum weight of the crane obtained from daily monitoring and statistics, convert it proportionally into the horizontal load borne by a single precast steel pipe structure. Then, check the foundation bearing capacity value of the soil at the depth of the construction soil layer in the geological survey report, as well as the distribution information and soil mechanics parameters of the soil layer above that depth, to determine the depth and position of the end of the precast steel pipe structure drilled into the soil layer. S2. The factory prefabricates the prefabricated manhole cover structure, prefabricated steel pipe structure, outer steel pipe, and premixed self-compacting quick-setting concrete material, and transports them to the construction site after they are ready. S3. At the construction site, first remove the old manhole cover and dig a ring pit around the original vertical shaft; S4. Along the driving direction, drill into the precast steel pipe structure in a rotary motion at the middle of both sides and the upper and lower middle sides of the ring pit. S5. Twist open the outer steel pipe in the precast steel pipe structure and pull it out; S6. Press the inner steel pipe in the prefabricated steel pipe structure downwards so that the steel bar structure at the lower end of the prefabricated steel pipe structure is fully opened. S7. A precast steel sleeve is fitted onto the upper part of the precast steel pipe structure, and premixed self-compacting quick-setting concrete is injected into the grouting port of the precast steel sleeve. S8. After the grouting is completed, cover the prefabricated well cover structure so that the positioning protrusion of the prefabricated steel structure of the prefabricated well cover structure is fully inserted into the grouting port of the prefabricated steel sleeve. S9. Fill the ring pit with a layer of self-compacting quick-setting concrete and an asphalt layer in sequence. Fill the reserved area near the manhole cover with high-elasticity plastic track material. After completion, compact the road surface.

10. The multi-heavy-vehicle road section manhole cover system and its construction method according to claim 9, characterized in that, In step S1, the drilling length and end resistance of a single precast steel pipe are determined, and the frictional resistance is calculated through the bearing capacity of the precast steel pipe structure. The resistance provided by the end of the precast steel pipe structure is the sum of the end resistance and the frictional resistance. Then, the resistance value provided by the end of the precast steel pipe structure is corrected through indoor tests, and the precast parameters of each component in the factory precast steel pipe structure are obtained.

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