A steel-concrete composite pipe jacking back wall

Abstract

This utility model relates to a steel-concrete composite pipe jacking back wall, comprising a concrete block, a reinforcing steel skeleton, a front steel plate, a rear steel plate, lifting rings, and strain gauges. The reinforcing steel skeleton is embedded in the concrete block. At least two lifting rings are provided on the top of the concrete block, and the lifting rings are fixedly connected to the reinforcing steel skeleton. The front and rear steel plates are respectively fixedly installed on the front and rear end faces of the concrete block. The strain gauges are installed on the inner surface of the front steel plate and embedded in the concrete block, and the strain gauges are connected to a controller. This utility model combines steel plates and concrete structures, which can effectively reduce the thickness of the back wall, reduce transportation and hoisting costs, and can be transported and reused using a crane. It can monitor and provide feedback on the pressure in real time, avoiding damage caused by pressure overload. Compared with traditional concrete back walls, the number of reuses is greatly increased, resulting in lighter weight, higher strength, longer lifespan, and lower overall cost.

Description

Technical Field

[0001] This utility model relates to the field of pipeline construction technology, specifically to a steel-concrete combined pipe jacking back wall. Background Technology

[0002] In the construction of storm and sewage pipe jacking wells, the pipe jacking method involves using the jacking force generated by jacking equipment within the working pit to move the pipe from one horizontal working well to another. Typically, a backrest is installed on the inner wall of the working well to support the jacking equipment. The fabrication of the backrest for traditional caissons requires on-site formwork erection, rebar tying, concrete pouring, and concrete curing until the design strength is reached before use.

[0003] However, cast-in-place backrests require a large amount of concrete, steel bars and formwork materials, and require on-site formwork, steel bar tying, pouring and curing. The amount of manual labor is large. In narrow or complex terrain, formwork is difficult to set up, occupies a large working space and affects the parallel operation of other processes.

[0004] Furthermore, the traditional cast-in-place backrest is a bulky structure that is difficult to transport over long distances. After dismantling, it cannot be transferred to other well sites for use. It usually needs to be cast on-site, making it a one-time structure. Construction of multiple well sites requires repeated investment of resources, and each well site needs to be cast repeatedly. Materials cannot be reused, and the subsequent removal of the backrest leads to additional costs.

[0005] Furthermore, traditional concrete backrests are fixed structures, unable to adjust their stress state in real time according to changes in jacking force during the jacking process. This makes them prone to localized overload or structural deformation due to fluctuations in jacking force. Without integrated pressure sensors or monitoring systems, construction personnel cannot monitor the stress distribution on the backrest in real time, and cannot provide timely warnings of potential risks.

[0006] Therefore, it is necessary to study a steel-concrete composite pipe jacking back wall. Utility Model Content

[0007] Therefore, the purpose of this utility model is to provide a steel-concrete combined jacking pipe back wall, which can effectively solve the problems of cumbersome construction, low turnover efficiency, high cost and inability to provide pressure warning of existing cast-in-place back walls.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A steel-concrete composite pipe jacking back wall includes a concrete block, a steel reinforcement cage, a front steel plate, a rear steel plate, a lifting ring, and strain gauges.

[0010] The steel reinforcement cage is embedded in the concrete block;

[0011] The top of the concrete block is provided with at least two lifting rings, which are fixedly connected to the steel reinforcement cage;

[0012] The front steel plate and the rear steel plate are respectively fixedly installed on the front and rear end faces of the concrete block;

[0013] The strain gauge is installed on the inner surface of the front steel plate and embedded in the concrete block. The strain gauge is connected to the controller.

[0014] Furthermore, the steel reinforcement cage includes upper main reinforcement, lower main reinforcement, and tie bars;

[0015] The upper and lower main reinforcement bars are pre-embedded in the concrete block in parallel, and are located at the top and bottom of the concrete block respectively; multiple sets of tie bars are vertically fixedly connected between the upper and lower main reinforcement bars.

[0016] Furthermore, the inner surfaces of both the front and rear steel plates are fixedly connected with several studs, which are pre-embedded in the concrete block.

[0017] Furthermore, concrete pads are fixed to the front and rear ends of the steel reinforcement cage, and the front and rear steel plates are fixedly attached to the corresponding concrete pads.

[0018] Furthermore, a conduit is pre-embedded in the concrete block, and a cable is installed in the conduit. The controller is installed on the side wall of the concrete block, and the strain gauge is connected to the controller via the cable.

[0019] Furthermore, the controller is connected to a light alarm module.

[0020] The beneficial effects of the above technical solution are:

[0021] This utility model combines steel plates and concrete structures, effectively reducing the thickness of the back wall and lowering transportation and hoisting costs. The back wall adopts a modular design, with at least two lifting rings on the top of the concrete block, allowing for crane lifting and relocation. Combined with strain gauges, controllers, and lighting alarm modules, it can monitor and provide feedback on the pressure in real time for adjustment, avoiding damage caused by pressure overload. Compared to traditional concrete back walls, the number of reusability is greatly increased. With lighter weight, higher strength, longer lifespan, and lower overall cost, it is suitable for pipe jacking projects in densely populated urban areas and complex geological conditions, serving as a model of green construction and industrialized building. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the steel reinforcement cage of this utility model;

[0023] Figure 2 This is a schematic diagram of the concrete block and strain gauge of this utility model;

[0024] Figure 3 for Figure 2A side view diagram;

[0025] Figure 4 This is a schematic diagram of the strain gauge and controller of this utility model.

[0026] Attached reference numerals: 1 is a concrete block, 2 is a steel reinforcement cage, 3 is a front steel plate, 4 is a rear steel plate, 5 is a lifting ring, 6 is a strain gauge, 7 is a controller, 8 is a stud, 9 is a concrete pad, 10 is a conduit, 11 is a light alarm module, 201 is an upper main reinforcement, 202 is a lower main reinforcement, and 203 is a tie bar. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] This embodiment aims to provide a steel-concrete composite pipe jacking back wall, which is mainly used as the core load-bearing structure for pipe jacking reaction force in the construction of rainwater and sewage pipe jacking wells. It addresses the problems of existing cast-in-place back walls, such as cumbersome construction, low turnover efficiency, high cost, and inability to provide pressure warning.

[0029] A steel-concrete composite pipe jacking back wall includes a concrete block 1, a steel reinforcement frame 2, a front steel plate 3, a rear steel plate 4, a lifting ring 5, and strain gauges 6. The back wall is 3m long × 3m wide × 0.3m thick, with an internal reinforced concrete structure 0.2m thick, and is covered with 5cm thick steel plates at both the front and back.

[0030] like Figure 1 The reinforcing steel cage 2 is pre-embedded in the concrete block 1, serving as a skeletal support for the concrete block 1. Specifically, the reinforcing steel cage 2 includes upper main reinforcement 201, lower main reinforcement 202, and tie bars 203; the upper and lower main reinforcement 201 and 202 are pre-embedded parallel to each other in the concrete block 1, located at the upper and lower parts of the concrete block 1, respectively; both the upper and lower main reinforcement 201 and 202 are made of 14mm diameter HRB400 threaded steel, arranged in both horizontal and vertical directions, with a horizontal and vertical spacing of 150mm and cross-tied, forming a double-layer reinforcing steel mesh skeleton structure. In other embodiments, the spacing of the main reinforcement or the size of the steel plate can be adjusted to adapt to different jacking pipe diameters and jacking force requirements.

[0031] There are multiple sets of tie bars 203 vertically fixedly connected between the upper main reinforcement 201 and the lower main reinforcement 202. The tie bars 203 are made of 12mm diameter HRB400 threaded steel bent into a "U" shape and tied at the intersection of the main reinforcement at a spacing of 300mm×300mm to enhance the shear resistance.

[0032] At least two lifting rings 5 ​​are provided on the top of the concrete block 1. The lifting rings 5 ​​are fixedly connected to the steel reinforcement skeleton 2. The lifting rings 5 ​​are made of 30mm diameter round steel bent into an "Ω" shape and welded to the top main reinforcement. The exposed part is ≥200mm in length.

[0033] like Figure 3 The front steel plate 3 and the rear steel plate 4 are fixedly installed on the front and rear end faces of the concrete block 1, respectively. Both the front steel plate 3 and the rear steel plate 4 are made of Q355B steel plate (50mm thick) and are used to form a composite load-bearing structure with the concrete. Several Φ16×80mm studs 8 are welded to the inner surfaces of the front steel plate 3 and the rear steel plate 4. The studs 8 are pre-embedded in the concrete block 1 to enhance the mechanical interlocking force between the steel plate and the concrete.

[0034] Concrete pads 9 are fixed to the front and rear ends of the steel reinforcement cage 2. The front steel plate 3 and the rear steel plate 4 are fixedly attached to the corresponding concrete pads 9 to control the thickness of the steel reinforcement protective layer. The bottom and side surfaces of the steel reinforcement protective layer are ≥40mm, and the top surface is ≥30mm.

[0035] During the pouring of concrete block 1, the front steel plate 3 and the rear steel plate 4 are directly used for the front and rear formwork, together with the bottom formwork and side formwork, to form a 0.3m thick cavity for pouring concrete. During pouring, C40 concrete is poured in from the top and vibrated in layers (each layer ≤300mm) to ensure that the steel plates are in close contact with the concrete.

[0036] like Figure 2 and Figure 4 Four 30×30mm strain gauges 6 are welded to the inner surface of the front steel plate 3, with a center-to-center distance of 1m on each side. The area around each strain gauge 6 within 200mm is manually compacted using a vibrator to prevent direct contact between the vibrator and the strain gauges. A conduit 10, made of PVC, is pre-embedded in the concrete block 1, containing cables that extend to a junction box at the edge. A controller 7 is mounted on the side wall of the concrete block 1. The strain gauges 6 are connected to the controller 7 via cables. The controller 7 controls a light alarm module 11, which has green, yellow, and red warning lights. Each color corresponds to a pressure threshold, and the light alarm module displays a different color based on the maximum pressure detected by the strain gauges 6. Figure 4 From left to right, the three pressure data states are green light, red light, and yellow light.

[0037] The working principles and specific structures of strain gauge 6, controller 7 and light alarm module 11 are based on existing technologies and will not be elaborated here.

[0038] The backrest wall is hoisted to the well site using a crane. Regarding the selection of the crane, the self-weight of the backrest needs to be calculated first. In this embodiment, the density of C40 concrete is about 2.4t / m³, and the volume is 3×3×0.3=2.7m³. The total weight of reinforced concrete + steel plate is about 11 tons. The crane load needs to be ≥1.5 times the safety factor, that is, more than 16 tons.

[0039] During lifting, first suspend the crane 100mm off the ground for 3 minutes for a trial lift to observe the deformation of the backrest and the stability of the lifting point. Once no abnormalities are confirmed, the formal lifting can proceed. The hook must be equipped with an anti-disengagement device, and the slings must be steel wire ropes with a diameter ≥20mm (breaking strength ≥20 tons). Move the crane at a constant speed during lifting; sudden stops and starts are prohibited to prevent structural cracking or monitoring system failure due to inertial impact. The lifting height should be controlled within 1m off the ground to reduce the risk of accidental falls.

[0040] After hoisting to the well position, use a total station to calibrate the perpendicularity of the backrest to the jacking pipe axis (deviation ≤2mm / m). The contact surface between the front steel plate and the jack must be tight, with local gaps ≤1mm; if necessary, apply epoxy resin to fill the gaps.

[0041] Subsequently, connect the strain gauge 6 cable and perform no-load and simulated load tests to confirm that the light alarm signal response is normal. If strain gauge 6 data drift is found, it needs to be calibrated or replaced on-site.

[0042] The backrest wall in this invention combines steel plates and concrete structures, effectively reducing its thickness and lowering transportation and hoisting costs. The backrest wall features a modular design, with at least two lifting rings 5 ​​on the top of the concrete block 1, allowing for crane-assisted transport and relocation. Combined with strain gauges 6, a controller 7, and a lighting alarm module 11, it can monitor and provide real-time feedback on pressure conditions for adjustment, preventing damage from overload. Compared to traditional concrete backrest walls, it offers significantly increased reusability, lighter weight, higher strength, longer lifespan, and lower overall cost, surpassing traditional cast-in-place backrests. It is suitable for pipe jacking projects in densely populated urban areas and complex geological conditions, serving as a model of green construction and industrialized building.

Claims

1. A steel-concrete composite jacking pipe backwall, characterized in that: Includes concrete blocks, steel reinforcement cage, front steel plate, rear steel plate, lifting rings, and strain gauges; The steel reinforcement cage is embedded in the concrete block; The top of the concrete block is provided with at least two lifting rings, which are fixedly connected to the steel reinforcement cage; The front steel plate and the rear steel plate are respectively fixedly installed on the front and rear end faces of the concrete block; The strain gauge is installed on the inner surface of the front steel plate and embedded in the concrete block. The strain gauge is connected to the controller.

2. The steel-concrete combined pipe jacking backwall according to claim 1, characterized in that: The steel reinforcement cage includes upper main reinforcement, lower main reinforcement, and tie bars; The upper and lower main reinforcement bars are pre-embedded in the concrete block in parallel, and are located at the top and bottom of the concrete block respectively; multiple sets of tie bars are vertically fixedly connected between the upper and lower main reinforcement bars.

3. The steel-concrete combined pipe jacking backwall according to claim 1, characterized in that: The inner surfaces of both the front and rear steel plates are fixedly connected with several studs, which are pre-embedded in the concrete block.

4. The steel-concrete combined pipe jacking backwall according to claim 1, characterized in that: The front and rear ends of the steel reinforcement cage are fixed with concrete pads, and the front and rear steel plates are fixedly attached to the corresponding concrete pads.

5. A steel-concrete composite jacking pipe backwall according to any one of claims 1-4, characterized in that: A conduit is pre-embedded in the concrete block, and a cable is installed in the conduit. The controller is installed on the side wall of the concrete block, and the strain gauge is connected to the controller via a cable.

6. The steel-concrete combined pipe jacking backwall according to claim 5, characterized in that: The controller is connected to a light alarm module.

Images