Deep foundation pit for synchronously removing deeply-buried large abandoned raft plates in sensitive environment and construction method

Abstract

The invention relates to a synchronous removal deep foundation pit for deeply burying large waste rafts in a sensitive environment and a construction method. Comprising a prefabricated assembly type trestle plate step-by-step reinforced concrete supporting trestle technical system, a steel casing and rapid prefabricated assembly type water collecting pit setting technical system, a waste bottom plate block-by-block breaking-first-cutting-crushing-dismantling technical system and a reserved pile filling hole position segment-by-segment block-by-layer backfilling technical system. The construction method has the beneficial effects that rapid construction of the reinforced concrete supporting trestle is achieved, the structural stability is guaranteed, and the construction efficiency is improved; high efficiency and quality control of construction of the stand column pile are achieved, meanwhile, the concrete over-filling amount is reduced, and the construction economical efficiency is improved; rapid setting and automatic management of the sump are realized, and the construction efficiency and the reliability of a drainage system are effectively improved; safe and efficient dismantling of the waste bottom plate is achieved, the construction precision is guaranteed, and the operation efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground foundation pits, and particularly relates to a deep foundation pit for synchronously removing a large buried abandoned raft in a sensitive environment and a construction method thereof. Background Art

[0002] With the rapid advancement of urban construction in China, the available land resources for urban development are becoming increasingly scarce, prompting urban construction to tend towards high-rise and the expansion of underground space. This trend has directly led to the foundation pit projects in many construction projects showing the characteristics of complex shapes and significant excavation depths. The construction technology for synchronously removing a deep foundation pit with a large buried abandoned raft in a sensitive environment is a research hotspot in urban underground space development in recent years, and the characteristics of its technical application are mainly reflected in the following aspects: This technology adopts a process combining mechanical crushing and synchronous support, which can achieve the efficient removal of the abandoned raft and the synchronous construction of the deep foundation pit, significantly shortening the construction period; through micro-vibration control technology and a real-time monitoring system, the impact of construction on the surrounding sensitive environment can be effectively reduced; the use of modular equipment combinations can adapt to different geological conditions and project scale requirements, with strong flexibility. Currently, this technology has been applied in some urban underground space renovation projects, such as subway extension projects, underground commercial complex construction and other scenarios.

[0003] However, there are still several obvious deficiencies in this technology: Firstly, the crushing efficiency for ultra-thick concrete rafts still needs to be improved, and the existing equipment has high energy consumption when operating in hard rock layers or areas with dense steel bars; secondly, the coordination between the synchronous support system and the removal process is insufficient, which is likely to cause the local deformation of the foundation pit to exceed the standard; furthermore, under complex hydrogeological conditions, groundwater control and the treatment of abandoned concrete residues still face challenges, which may lead to the risk of surrounding stratum settlement.

[0004] For the deep foundation pit for synchronously removing a large buried abandoned raft in a sensitive environment and the construction method thereof, there is an urgent need to propose a construction method that can improve construction efficiency while ensuring project quality and safety. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a deep foundation pit for synchronously removing a large buried abandoned raft in a sensitive environment and a construction method thereof.

[0006] This construction system for synchronously removing a large buried abandoned raft foundation in a sensitive environment and deep foundation pit includes a construction system for synchronously removing a large buried abandoned raft foundation in a sensitive environment, characterized by: including a technical system for prefabricated assembled trestle plates to gradually implement a reinforced concrete support trestle, steel casing, a technical system for quickly setting up prefabricated assembled sump pits, a technical system for disassembling, cutting, and crushing the abandoned floor slab in sections first and then in pieces, and a technical system for sectional, block, and layered backfilling of reserved pile hole positions; the bottom of the technical system for prefabricated assembled trestle plates to gradually implement a reinforced concrete support trestle is provided with cast-in-place concrete piles and fixed at the bottom of the foundation pit, the top is provided with a steel plate trestle deck, and both ends of the steel plate trestle deck are connected to the ground outside the foundation pit; the steel casing is spliced by several steel casing segments; the technical system for quickly setting up prefabricated assembled sump pits includes a steel sump tank; the steel sump tank is arranged at the bottom of the foundation pit; the steel sump tank is connected with a drain pipe; the technical system for disassembling, cutting, and crushing the abandoned floor slab in sections first and then in pieces includes a moving frame body, and the moving frame body is connected with a marking device, a disassembling device, and a cutting and crushing device; the technical system for sectional, block, and layered backfilling of reserved pile hole positions includes embedded holes, and the embedded holes are opened at the bottom of the foundation pit.

[0007] Preferably, the technical system for prefabricated assembled trestle plates to gradually implement a reinforced concrete support trestle includes a trestle body; the trestle body includes lattice columns, horizontal crossbars, and inclined trestle supports; the two sides of the technical system for prefabricated assembled trestle plates to gradually implement a reinforced concrete support trestle are provided with retaining piles, multiple lattice columns are arranged between the retaining piles, and horizontal crossbars and inclined trestle supports are arranged between the retaining piles and the lattice columns; the bottom of the lattice columns is provided with cast-in-place concrete piles; the lattice columns are connected with steel corbels; the inclined trestle supports are connected to the steel corbels and are connected to the lattice columns at both ends; the upper part of the trestle body is paved with a steel plate trestle deck.

[0008] Preferably, the steel casing segments include a first segment, a last segment, and several standard segments; adjacent steel casing segments are fixed through fixed connectors, and a concrete delivery pipe is inserted into the segments; the end of the first segment is provided with a serrated structure for stable entry into the mud, and the last segment is provided with an arc-shaped chamfer structure.

[0009] Preferably, the steel sump tank includes a water extraction pipe, a water inlet pipe, and a cover plate; the cover plate is arranged on the top of the steel sump tank; the cover plate is provided with a sump tank opening; a water pump is arranged inside the steel sump tank, one end of the water pump is connected to the water extraction pipe, and the other end is connected to the drain pipe; the end of the water extraction pipe is located at the bottom of the steel sump tank; the end of the drain pipe is located outside the bottom of the foundation pit; a wireless water level detector is arranged inside the steel sump tank; and a manual operation platform is arranged at the sump tank opening.

[0010] Preferably, the technical system for dismantling, cutting and crushing the discarded bottom slab in sections includes a movable frame; the movable frame includes a steel cross beam and columns; columns are welded at the four corners of the steel cross beam, and movable wheels are provided at the bottoms of the four columns; a marking device is arranged between the steel cross beams, and the marking device includes a funnel and a lime discharge port; binding straps are arranged on both sides of the steel cross beam, and male and female buckles are respectively connected to the ends of the binding straps, and a dismantling device and a cutting and crushing device are bound through the cooperation of the male and female buckles.

[0011] Preferably, the embedded holes include several segments; loose materials are laid in the segments, and waterproof geotextiles are provided on the surfaces of the segments.

[0012] The construction method of the construction system for synchronously clearing a deep foundation pit of a large buried discarded raft slab in a sensitive environment is characterized by including the following steps: S1. Install the technical system of the reinforced concrete support trestle by stepwise implementation of precast trestle slabs: First, construct concrete cast-in-place piles at the bottom of the technical system of the reinforced concrete support trestle by stepwise implementation of precast trestle slabs as the foundation, and lay a steel sheet trestle deck on the upper part of the technical system of the reinforced concrete support trestle by stepwise implementation of precast trestle slabs to complete the construction of the trestle; S2. Install steel casing: First implant the first segment of the steel casing into the soil layer, and then sequentially connect several steel casing segments; after the assembly is completed, pour concrete into the steel casing; S3. Install the technical system of quickly setting precast assembled sump: Install a steel water collection tank at the bottom of the foundation pit, and install a drain pipe on the side wall of the steel water collection tank as a drainage channel; S4. Install the technical system for dismantling, cutting and crushing the discarded bottom slab in sections first and then: First assemble the movable frame, set a marking device on the movable frame, and accurately mark the parts of the discarded bottom slab to be demolished; then fix the dismantling device and the cutting and crushing device on the movable frame in sequence; finally, perform a step-by-step demolition operation surface of first dismantling and then cutting and crushing at the marked positions; S5. Install the technical system for sectional, block and layered backfilling of reserved pile hole positions: First lay a temporary support structure in the embedded holes at the bottom of the foundation pit; when pile supplement construction is required, gradually dig out the temporary support structure in a sectional and layered manner.

[0013] Preferably, in step S1, for the prefabricated and assembled trestle slab for the step-by-step implementation of the reinforced concrete supported trestle technology system, retaining piles are provided on both sides, multiple lattice columns are provided between the retaining piles, horizontal cross bars and inclined trestle supports are provided between the retaining piles and the lattice columns; a cast-in-place concrete pile is provided at the bottom of the lattice column; a steel corbel is connected to the lattice column; the inclined trestle support is connected to the steel corbel and is connected to the lattice columns at both ends; first, cast-in-place concrete piles are constructed between the retaining piles on both sides as the foundation, and vertical lattice columns are installed thereon; secondly, the lattice columns are connected by horizontal cross bars to form the main framework, and steel corbels are installed on the lattice columns to enhance the joint strength; then, the inclined trestle supports are erected and connected to the main framework to form a stable trestle body; finally, a steel plate trestle deck is laid on the upper part of the trestle body to complete the construction of the trestle.

[0014] Preferably, in step S3, the cover plate is arranged on the top of the steel water tank; the cover plate is provided with a water tank opening; a wireless water level detector is arranged inside the steel water tank, and real-time water level monitoring is realized through the wireless water level detector; an artificial operation platform is arranged at the water tank opening, and the opening and closing operation of the cover plate is manually controlled.

[0015] The beneficial effects of the present invention are as follows: 1) The prefabricated and assembled trestle slab for the step-by-step implementation of the reinforced concrete supported trestle technology system of the present invention realizes the rapid construction of the reinforced concrete supported trestle through modular prefabricated components and step-by-step assembly processes, ensuring both structural stability and construction efficiency.

[0016] 2) The steel casing of the present invention realizes the high efficiency and quality control of the construction of the column pile through the modular steel casing segment design and reliable connection method, while reducing the over-pouring amount of concrete and improving the construction economy.

[0017] 3) The rapid setting prefabricated and assembled sump technology system of the present invention realizes the rapid setting and automatic management of the sump through the prefabricated and assembled design and intelligent monitoring system, effectively improving the construction efficiency and the reliability of the drainage system.

[0018] 4) The waste floor block-by-block disintegration and then cutting and crushing demolition technology system of the present invention realizes the safe and efficient demolition of the waste floor through the modular moving frame and multi-functional marking and positioning system, ensuring both construction accuracy and operation efficiency. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the prefabricated and assembled trestle slab for the step-by-step implementation of the reinforced concrete supported trestle technology system; Figure 2 is a schematic structural diagram of the steel casing; Figure 3 is a schematic structural diagram of the rapid setting prefabricated and assembled sump technology system; Figure 4 It is a schematic structural diagram of the technical system for dismantling, cutting, and crushing the abandoned bottom slab in sections first and then removing it; Figure 5 It is a schematic structural diagram of the technical system for backfilling the reserved pile hole positions in sections, blocks, and layers.

[0020] Description of the reference numerals in the drawings: 1 lattice column, 2 steel corbel, 3 retaining pile, 4 inclined trestle support, 5 steel plate trestle deck, 6 horizontal cross-bar, 7 trestle body, 8 cast-in-place concrete pile, 9 chamfer, 10 standard section, 11 first section, 12 concrete delivery pipe, 13 last section, 14 fixed connecting piece, 15 steel casing, 16 serrated stable connection into the mud, 17 drain pipe, 18 water pump, 19 cover plate, 20 water extraction pipe, 21 opening of the steel water tank, 22 wireless water level detector, 23 manual operation platform, 24 water inlet pipe, 25 bottom of the foundation pit, 26 steel water tank, 27 movable frame body, 28 column, 29 funnel, 30 lime discharge port, 31 female buckle, 32 strap, 33 steel cross beam, 34 male buckle, 35 movable wheel, 36 bulk material, 37 embedded hole, 38 waterproof geotextile, 39 section. Specific implementation manners

[0021] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0022] Embodiment 1 As an embodiment, a construction system for synchronously removing a deep foundation pit of a large-scale abandoned raft buried deeply in a sensitive environment is proposed, as Figures 1-5As shown, it includes a technical system for prefabricated precast trestle slabs to implement reinforced concrete support trestles step by step, a steel casing 15, a technical system for quickly setting up prefabricated precast sumps, a technical system for demolishing the abandoned bottom slab by disassembling it in sections first and then cutting and crushing it, and a technical system for backfilling the reserved pile hole positions in sections, blocks, and layers. The technical system for prefabricated precast trestle slabs to implement reinforced concrete support trestles step by step is provided with concrete cast-in-place piles 8 at the bottom and fixed at the bottom 25 of the foundation pit, and a steel plate trestle deck 5 at the top. Both ends of the steel plate trestle deck 5 are connected to the ground outside the foundation pit. The steel casing 15 is spliced by several steel casing segments. The technical system for quickly setting up prefabricated precast sumps includes a steel-made water collection tank 26. The steel-made water collection tank 26 is arranged at the bottom 25 of the foundation pit. The steel-made water collection tank 26 is connected with a drain pipe 17. The technical system for demolishing the abandoned bottom slab by disassembling it in sections first and then cutting and crushing it includes a moving frame body 27. The moving frame body 27 is connected with a marking device, a disassembling device, and a cutting and crushing device. The technical system for backfilling the reserved pile hole positions in sections, blocks, and layers includes embedded holes 37, and the embedded holes 37 are opened at the bottom 25 of the foundation pit.

[0023] As Figure 1 shown, the technical system for precast precast trestle slabs to implement reinforced concrete support trestles step by step includes setting multiple vertical lattice columns 1, horizontal crossbars 6, and inclined trestle supports 4 between the retaining piles 3 on both sides to form a trestle body 7, and laying a steel plate trestle deck 5 on the upper part. The bottom of the lattice column 1 is provided with a concrete cast-in-place pile 8 to enhance the bottom stability. Steel corbels 2 are arranged under the lattice column 1 and under the inclined trestle support 4 to improve the overall strength of the trestle body 7.

[0024] As Figure 3 shown, the technical system for quickly setting up prefabricated precast sumps includes setting a steel-made water collection tank 26 at the bottom 25 of the foundation pit. The steel-made water collection tank 26 is composed of a water pump 18, a water suction pipe 20, a water inlet pipe 24, a drain pipe 17, a cover plate 19, and a water collection tank opening 21. At the same time, a wireless water level detector 22 is also arranged inside the steel-made water collection tank 26 to monitor the water level in the tank in real time. An artificial operation platform 23 is arranged beside the water collection tank opening 21 to facilitate manual control of the opening and closing of the water collection tank.

[0025] As Figure 4 shown, the technical system for demolishing the abandoned bottom slab by disassembling it in sections first and then cutting and crushing it includes a moving frame body 27. The moving frame body 27 includes a steel cross beam 33 and columns 28. The steel cross beam 33 is welded with columns 28 at the four corners, and moving wheels 35 are arranged at the bottoms of the four columns 28. A marking device is arranged between the steel cross beams 33. The marking device includes a funnel 29 and a lime discharge port 30. Binding straps 32 are arranged on both sides of the steel cross beam 33. The ends of the binding straps 32 are respectively connected with a male buckle 34 and a female buckle 31. A disassembling device and a cutting and crushing device are bound through the cooperation of the male buckle 34 and the female buckle 31.

[0026] Example 2 As another embodiment, this second embodiment is proposed on the basis of the first embodiment, which is a more specific construction system for synchronously removing deep foundation pits of large buried raft slabs in sensitive environments.

[0027] As Figure 1 shown, the prefabricated and assembled trestle slab step-by-step implementation of the reinforced concrete support trestle technology system includes a trestle body 7; the trestle body 7 includes lattice columns 1, horizontal crossbars 6 and inclined trestle supports 4; there are retaining piles 3 on both sides of the prefabricated and assembled trestle slab step-by-step implementation of the reinforced concrete support trestle technology system, there are multiple lattice columns 1 between the retaining piles 3, and horizontal crossbars 6 and inclined trestle supports 4 are provided between the retaining piles 3 and the lattice columns 1; the bottom of the lattice column 1 is provided with a cast-in-place concrete pile 8; the lattice column 1 is connected with a steel corbel 2; the inclined trestle support 4 is supported and connected to the steel corbel 2 and is connected to the lattice column 1 at both ends; a steel plate trestle deck 5 is laid on the upper part of the trestle body 7.

[0028] As Figure 2 shown, the steel casing 15 is spliced by a first section 11, a last section 13 and several standard sections 10, and adjacent sections are fixed by fixed connectors 14. After assembly, a concrete delivery pipe 12 is inserted and concrete is poured. The end of the first section 11 is provided with a serrated stable structure 16 for entering the mud, and the last section 13 is provided with an arc chamfer 9 structure.

[0029] As Figure 3 shown, the steel water collection tank 26 includes a water extraction pipe 20, a water inlet pipe 24 and a cover plate 19; the cover plate 19 is arranged on the top of the steel water collection tank 26; the cover plate 19 is provided with a water collection tank opening 21; a water extraction pump 18 is arranged inside the steel water collection tank 26, one end of the water extraction pump 18 is connected to the water extraction pipe 20, and the other end is connected to a drain pipe 17; the end of the water extraction pipe 20 is located at the bottom of the steel water collection tank 26; the end of the drain pipe 17 is located outside the bottom 25 of the foundation pit; a wireless water level detector 22 is arranged inside the steel water collection tank 26; an artificial operation platform 23 is arranged at the water collection tank opening 21 As Figure 4 shown, the technology system for dismantling and cutting and crushing the abandoned bottom slab in blocks first includes installing a movable frame body 27. The movable frame body 27 is welded by a steel cross beam 33 and columns 28, and movable wheels 35 are arranged at the bottoms of the four columns 28. A funnel 29 and a lime discharge port 30 are arranged between the steel cross beams 33, and the parts to be demolished can be marked; binding belts 32 are arranged on both sides to connect the male buckle 34 and the female buckle 31 respectively, and the disassembling device and the cutting and crushing device can be bound successively, and the construction of first disassembling and then cutting and crushing is carried out for the marked positions.

[0030] As Figure 5As shown, in the technical system of sectional, block and layer-by-layer backfilling of reserved pile-complement holes, loose materials 36 are laid in sections 39 in the embedded holes 37 preset at the bottom of the foundation pit 25, and a layer of waterproof geotextile 38 is arranged on the surface. During construction, the loose materials 36 are dug out in blocks and layers, and the process of pile complement can be carried out in the holes.

[0031] It should be noted that the parts identical or similar to those in Embodiment 1 in this embodiment can be referred to each other, and will not be described in detail in this application.

[0032] Embodiment 3 As another embodiment, this Embodiment 3 is proposed on the basis of Embodiment 2. A construction method for synchronously clearing a deep foundation pit of a large buried abandoned raft in a sensitive environment is as Figures 1-5 shown, and includes the following steps: S1. Install the technical system of reinforced concrete support trestle by stepwise implementation of precast assembled trestle boards: First, construct concrete cast-in-place piles 8 at the bottom of the technical system of reinforced concrete support trestle by stepwise implementation of precast assembled trestle boards as the foundation, and lay a steel trestle deck 5 on the upper part of the technical system of reinforced concrete support trestle by stepwise implementation of precast assembled trestle boards to complete the construction of the trestle; S2. Install the steel casing 15: First implant the first section of the steel casing 15 into the soil layer, and then successively connect several sections of the steel casing; after assembly, pour concrete into the steel casing 15; S3. Install the technical system of quickly setting precast assembled sump: Install a steel sump tank 26 at the bottom of the foundation pit 25, and install a drain pipe 17 on the side wall of the steel sump tank 26 as a drainage channel; S4. Install the technical system of disassembling first and then cutting and crushing the abandoned floor in blocks: First assemble a movable frame 27, set a marking device on the movable frame 27, and accurately mark the parts of the abandoned floor to be demolished; then fix a disassembling device and a cutting and crushing device on the movable frame 27 successively; finally, carry out a step-by-step demolition operation surface of disassembling first and then cutting and crushing for the marked positions; S5. Install the technical system of sectional, block and layer-by-layer backfilling of reserved pile-complement holes: First, lay a temporary support structure in the embedded hole 37 at the bottom of the foundation pit 25; when pile complement construction is required, gradually dig out the temporary support structure in a block-by-block and layer-by-layer manner.

[0033] As Figure 1As shown in the figure, in step S1, the prefabricated and assembled trestle slab is used to implement the reinforced concrete support trestle technology system step by step. First, cast-in-place concrete piles 8 are constructed between the two side retaining piles 3 as the foundation, and vertical lattice columns 1 are installed thereon. Secondly, each lattice column 1 is connected by a transverse horizontal bar 6 to form a main framework, and steel corbels 2 are installed on the lattice columns 1 to enhance the joint strength. Then, diagonal trestle supports 4 are erected and connected to the main framework to form a stable trestle body 7. Finally, a steel plate trestle deck 5 is laid on the upper part of the trestle body 7 to complete the construction of the trestle.

[0034] The prefabricated and assembled trestle slab implements the reinforced concrete support trestle technology system step by step through modular prefabricated components and step-by-step assembly processes, realizing the rapid construction of the reinforced concrete support trestle, ensuring both structural stability and construction efficiency.

[0035] As Figure 2 shown in the figure, in step S2, a steel casing 15 is installed, including first implanting the first section 11 of the steel casing 15 into the soil layer through the serrated structure 16 for stabilizing into the mud at the end, and then successively connecting the standard section 10 and the last section 13, and reliable connection is carried out between each section through a fixed connecting piece 14; after the assembly is completed, a concrete delivery pipe 12 is inserted into the steel casing 15 for concrete pouring construction, and the arc chamfer 9 structure of the last section 13 facilitates the flow and compaction of the concrete.

[0036] The steel casing 15 realizes the high efficiency and quality control of the construction of the column pile through the modular design of the steel casing section and a reliable connection method, while reducing the over-pouring amount of concrete and improving the construction economy.

[0037] It should be noted that the same or similar parts in this embodiment and Embodiment 2 can be referred to each other and will not be elaborated in this application.

[0038] Embodiment 4 As another embodiment, this Embodiment 4 is proposed on the basis of Embodiment 3, and a more specific construction method for synchronously removing a deep foundation pit of a large buried abandoned raft in a sensitive environment.

[0039] As Figure 3 shown in the figure, in step S3, a rapid installation of a prefabricated and assembled sump technology system is installed. First, a steel sump tank 26 is positioned and installed at the bottom 25 of the foundation pit, a water pump 18 is connected to the sump tank through a water suction pipe 20, and a drain pipe 17 is installed as a drainage channel; secondly, a wireless water level detector 22 is arranged inside the sump tank, and real-time water level monitoring is realized through the water inlet pipe 24 of the wireless water level detector, and an artificial operation platform 23 is arranged beside the opening 21 of the sump tank to facilitate the manual control of the opening and closing operation of the cover plate 19.

[0040] The rapid - setting prefabricated sump technology system realizes the rapid setting and automated management of the steel sump tank 26 through prefabricated design and an intelligent monitoring system, effectively improving the construction efficiency and the reliability of the drainage system.

[0041] As Figure 4 shown, in step S4, the technology system for dismantling and cutting - breaking the discarded floor slab in sections first includes pre - assembling a movable frame 27, forming a main structure by welding steel cross - beams 33 and columns 28, and installing moving wheels 35 at the bottom of the four columns 28 to enable the movement of the frame; secondly, a funnel 29 and a lime discharge port 30 are arranged between the steel cross - beams 33 to accurately mark the position of the discarded floor slab to be demolished; then, the male buckle 34 and the female buckle 31 are connected by a strap 32 to fix the disassembly device and the cutting - breaking device in sequence; finally, a step - by - step demolition operation surface of first disassembling and then cutting - breaking is implemented for the marked position.

[0042] The technology system for dismantling and cutting - breaking the discarded floor slab in sections first realizes the safe and efficient demolition of the discarded floor slab through a modular movable frame 27 and a multi - functional marking and positioning system, ensuring both construction accuracy and operation efficiency.

[0043] As Figure 5 shown, in step S5, the technology system for sectional, block - by - block and layer - by - layer backfilling of the reserved pile - making hole positions first lays bulk materials 36 in sections 39 in the embedded holes 37 at the bottom of the foundation pit 25 to form a temporary support structure, and covers a waterproof geotextile 38 on the surface of the bulk materials 36 to prevent groundwater seepage from affecting the construction quality; when pile - making construction is required, the bulk materials 36 are gradually excavated in a block - by - block and layer - by - layer manner to ensure the stability of the hole wall during the excavation process and provide a safe working space for the pile - making process.

[0044] It should be noted that the same or similar parts in this embodiment and Embodiment III can be referred to each other and will not be elaborated in this application.

[0045] In this specification, each embodiment is described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

Claims

1. A construction system for deep burying of large abandoned rafts in sensitive environments and simultaneous removal of deep foundation pits, characterized in that: include: The prefabricated and assembled trestle slab implements the reinforced concrete supporting trestle technology system, steel casing, rapid setting of prefabricated and assembled water collection pit technology system, the abandoned bottom plate block dismantling and then cutting and crushing demolition technology system and the reserved pile hole segmentation and block layered backfilling technology system in steps; the prefabricated and assembled trestle slab implements the reinforced concrete supporting trestle technology system in steps, and the bottom is provided with concrete cast-in-place piles and fixed at the bottom of the foundation pit, and the top is provided with a steel plate trestle deck, and the two ends of the steel plate trestle deck are connected to the outer ground of the foundation pit; the steel casing is spliced ​​by several steel casing segments; the rapid setting of prefabricated and assembled water collection pit technology system includes a steel water collection tank; the steel water collection tank is arranged at the bottom of the foundation pit; the steel water collection tank is connected to a drainage pipe; the abandoned bottom plate block dismantling and then cutting and crushing demolition technology system includes a mobile frame, and the mobile frame is connected with a marking device, a dismantling device and a cutting and crushing device; the reserved pile hole segmentation and block layered backfilling technology system includes embedded holes, and the embedded holes are opened at the bottom of the foundation pit.

2. The construction system for deep buried large abandoned rafts and simultaneous removal of deep foundation pits in sensitive environments according to claim 1 is characterized in that: The reinforced concrete supported trestle technology system of prefabricated and assembled trestle slabs is implemented step by step, including the trestle body; the trestle body includes lattice columns, transverse horizontal bars and oblique trestle supports; the reinforced concrete supported trestle technology system of prefabricated and assembled trestle slabs is implemented step by step, and guard piles are arranged on both sides, multiple lattice columns are arranged between the guard piles, and transverse horizontal bars and oblique trestle supports are arranged between the guard piles and the lattice columns; concrete cast-in-place piles are arranged at the bottom of the lattice columns; the lattice columns are connected with steel corbels; the oblique trestle supports are connected to the steel corbels, and the two ends are connected with lattice columns; the upper part of the trestle body is paved with a steel plate trestle deck.

3. The construction system for deep buried large abandoned rafts in sensitive environments and simultaneous removal of deep foundation pits according to claim 1 is characterized in that: The steel casing segments include a first segment, a last segment and several standard segments; adjacent steel casing segments are fixed by fixed connectors, and a concrete delivery pipe is inserted into the segment; a sawtooth structure is provided at the end of the first segment to stabilize the entry into the mud, and an arc-shaped chamfered structure is provided at the last segment.

4. The construction system for deep buried large abandoned raft slabs in sensitive environments and simultaneous removal of deep foundation pits according to claim 1 is characterized in that: The steel water collecting tank includes a pumping pipe, a water inlet pipe and a cover plate; the cover plate is arranged on the top of the steel water collecting tank; the cover plate is provided with a water collecting tank opening; a pump is arranged inside the steel water collecting tank, one end of the pump is connected to the pumping pipe, and the other end is connected to the drainage pipe; the end of the pumping pipe is located at the bottom of the steel water collecting tank; the end of the drainage pipe is located outside the bottom of the foundation pit; a wireless water level detector is arranged inside the steel water collecting tank; and a manual operation platform is provided at the opening of the water collecting tank.

5. The construction system for deep buried large abandoned rafts and simultaneous removal of deep foundation pits in sensitive environments according to claim 1 is characterized in that: The technical system for dismantling the abandoned bottom plate by first dismantling it and then cutting and crushing it includes a mobile frame; the mobile frame includes steel beams and columns; columns are welded at the four corners of the steel beams, and moving wheels are provided at the bottom of the four columns; marking devices are provided between the steel beams, and the marking devices include a funnel and a lime discharge port; straps are provided on both sides of the steel beams, and the ends of the straps are respectively connected with male buckles and female buckles, and the dismantling device and the cutting and crushing device are bound together by the cooperation of the male buckles and the female buckles.

6. The construction system for deep buried large abandoned raft slabs in sensitive environments and simultaneous removal of deep foundation pits according to claim 1 is characterized in that: The embedded hole includes several segments; the segments are paved with bulk materials, and the surface of the segments is provided with waterproof geotextile.

7. The construction method of the construction system for deep buried large abandoned raft slabs and simultaneous removal of deep foundation pits in sensitive environments according to claim 1 is characterized in that: The following steps are involved: S1. Install the prefabricated trestle slab and implement the reinforced concrete supporting trestle technology system step by step: First, construct concrete cast-in-place piles at the bottom of the prefabricated trestle slab and implement the reinforced concrete supporting trestle technology system step by step as the foundation, and lay the steel plate trestle deck on the upper part of the prefabricated trestle slab and implement the reinforced concrete supporting trestle technology system step by step to complete the trestle construction; S2. Install the steel casing: implant the first segment of the steel casing into the soil layer in advance, and then connect several steel casing segments in sequence; after the assembly is completed, pour concrete into the steel casing; S3. Install the quick-set prefabricated water collection pit technology system: install a steel water collection tank at the bottom of the foundation pit, and install a drainage pipe on the side wall of the steel water collection tank as a drainage channel; S4. Install the technical system of dismantling the waste floor in blocks first and then cutting and crushing: pre-assemble the mobile frame, set a marking device on the mobile frame, and accurately mark the parts of the waste floor that need to be removed; then fix the dismantling device and the cutting and crushing device on the mobile frame in turn; finally, implement the step-by-step demolition operation surface of dismantling first and then cutting and crushing at the marked position; S5. Installation of reserved pile-filling holes and backfilling technology system in sections, blocks and layers: First, lay temporary support structures in the embedded holes at the bottom of the foundation pit; when pile-filling construction is required, the temporary support structures are gradually excavated in blocks and layers.

8. The construction method of the construction system for deep buried large abandoned raft slabs and simultaneous removal of deep foundation pits in sensitive environments according to claim 7, characterized in that: In step S1, the prefabricated assembled trestle slab implements the reinforced concrete supported trestle technical system step by step. Guarding piles are arranged on both sides, and multiple lattice columns are arranged between the guarding piles. Transverse horizontal bars and oblique trestle supports are arranged between the guarding piles and the lattice columns; concrete cast-in-place piles are arranged at the bottom of the lattice columns; the lattice columns are connected with steel brackets; the oblique trestle supports are connected to the steel brackets, and the lattice columns are connected at both ends; first, concrete cast-in-place piles are constructed between the guarding piles on both sides as the foundation, and vertical lattice columns are installed thereon; secondly, the lattice columns are connected by transverse horizontal bars to form the main frame, and steel brackets are installed on the lattice columns to enhance the node strength; then the oblique trestle supports are erected and connected to the main frame to form a stable trestle body; finally, the steel plate trestle deck is laid on the upper part of the trestle body to complete the trestle construction.

9. The construction method of the construction system for deep buried large abandoned raft slabs and simultaneous removal of deep foundation pits in sensitive environments according to claim 7, characterized in that: In step S3, a cover plate is arranged on the top of the steel water collecting tank; the cover plate is provided with a water collecting tank opening; a wireless water level detector is arranged inside the steel water collecting tank, and real-time water level monitoring is achieved through the wireless water level detector; a manual operation platform is arranged at the opening of the water collecting tank to manually control the opening and closing operation of the cover plate.

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