Fabricated working well open caisson construction method

Abstract

The invention discloses an assembly type working well open caisson construction method, and aims to provide an assembly type working well open caisson construction method which can effectively shorten the construction period, improve the construction safety and solve the problem that manual diving excavation is unsafe. The assembly type working well open caisson construction method is good in adaptability, and the construction cost can be effectively reduced. The method comprises the following steps: constructing a wellhead ring beam; mounting a ground steel blade foot; a base pipe ring is mounted above the steel blade foot, and an annular track is arranged on the inner wall of the base pipe ring; a hydraulic backhoe excavating device is mounted on the annular track and comprises a base moving along the annular track, a driving mechanism driving the base to move and a hydraulic backhoe bucket and / or a rotary cutting head arranged on the base; and the excavated soil sinks, an excavator and a hydraulic backhoe excavating device are adopted to excavate the soil in the well, and the hydraulic backhoe excavating device excavates the soil below the steel blade foot through a hydraulic backhoe bucket and / or a rotary cutting head.

Description

Technical Field

[0001] The present invention relates to the technical field of power working well construction, and particularly to a construction method for assembled working well caisson sinking. Background Art

[0002] In recent years, with the rapid economic growth and the continuous improvement of living standards, the power consumption has increased rapidly, and the construction volume of supporting facilities for cable laying, such as power working wells, has increased sharply. In particular, the demand for power tunnels in large and medium-sized cities is huge. At the same time, with the continuous maturity of the trenchless pipe jacking technology, more and more power tunnels adopt shield / tunnel jacking construction. In the shield / tunnel jacking project, the working well is an important part, providing a certain operating space for the shield tunnel jacking construction.

[0003] At present, the common construction methods for conventional vertical shaft working wells are the top-down method (foundation pit support + cut-off wall excavation), the bottom-up method (inverted well wall method), and the caisson sinking method. Among them, the caisson sinking method is widely used because of its high economy and the large number of working wells set due to the long path of the power tunnel. At present, the construction methods of caissons generally include: Conventional in-situ cast caissons on the ground. Since the construction method of sinking the caisson with the conventional in-situ cast well wall has problems such as the need for on-site casting of the well wall, long construction period, the need to set up a cut-off wall, large impact on the settlement of the surrounding environment, and unsafe manual diving excavation, this construction method will increasingly fail to meet the application scenarios of power tunnels. To solve the deficiencies of the conventional in-situ cast caissons on the ground, such as the need for on-site casting of the well wall and long construction period, some current caisson construction methods adopt the assembled caisson construction method. For example, Chinese Patent Publication No. CN116816353A, with the invention name of a construction method for a caisson for constructing an ultra-deep shield working well; however, the assembled caisson construction method also has problems such as the need to set up a cut-off wall, large impact on the settlement of the surrounding environment, and unsafe manual diving excavation.

[0004] Fully mechanical assembled caisson construction method. In order to improve the tunneling speed and labor efficiency, at present, various regions generally attach importance to and strengthen the research work on shaft tunneling technology, introduce modern technologies, and improve the tunneling process. The most prominent is to achieve construction mechanization in a centralized manner. For example, the currently used caisson shaft tunneling machine has the characteristics of compact structure, high construction efficiency, remote automatic control, and high well-forming accuracy. It can adopt the form of grab slag removal or mud-water slag removal according to factors such as geological conditions and moisture content. It is a construction method based on a new type of cantilever type open-excavation tunneling machine, especially suitable for ultra-deep power tunnel working wells; this construction method can effectively solve the above deficiencies, but since this construction method is a new type of construction method and there are few market equipment, the equipment rental and usage costs are high. Taking the commonly used assembled caisson with an inner diameter of 12.0m and a maximum excavation depth of 30m as an example, the equipment rental and usage costs reach 24 million yuan per well (including the mud treatment system), which greatly restricts the use of fully mechanical assembled caissons. Summary of the Invention

[0005] The object of the present invention is to provide a prefabricated working well caisson construction method which can not only effectively shorten the construction period, improve construction safety and solve the problem of unsafe manual diving excavation, but also has good adaptability and can effectively reduce construction costs.

[0006] The technical solution of the present invention is as follows: A prefabricated working well caisson construction method, comprising the following steps: Construct the wellhead ring beam; Install the ground steel cutting edge; Install a base pipe ring above the steel cutting edge, and an annular track is provided on the inner wall of the base pipe ring; Install a hydraulic backhoe excavation device on the annular track, which includes a base moving along the annular track, a driving mechanism for driving the base to move, and a hydraulic backhoe bucket and / or a rotary cutting head provided on the base; Excavate and sink. Use an excavator and a hydraulic backhoe excavation device to excavate soil in the well. The hydraulic backhoe excavation device excavates the soil under the steel cutting edge through the hydraulic backhoe bucket and / or the rotary cutting head. In the prefabricated working well caisson construction method of this solution, the excavation work is completed by the cooperation of an excavator and a hydraulic backhoe excavation device. The main excavation work in the well is completed by the excavator. For the part under the steel cutting edge where it is difficult to carry out excavation work by the excavator, there is no need to adopt manual excavation operation. The driving mechanism can drive the base to move along the annular track, thereby driving the hydraulic backhoe excavation device to move along the annular track, and the excavation work under the steel cutting edge is completed by the hydraulic backhoe excavation device, ensuring that there is no need for manual excavation operation throughout the process, thereby improving construction safety and solving the problem of unsafe manual diving excavation.

[0007] Compared with the conventional in-situ cast-in-place reinforced concrete on the ground and manual excavation of the caisson, the work efficiency of the prefabricated working well caisson construction method of this solution is increased by 50%, which can effectively shorten the construction period, improve construction safety and solve the problem of unsafe manual diving excavation.

[0008] Compared with the existing fully mechanical prefabricated caisson construction method, which has high equipment rental and usage costs, especially equipment rental fees and labor costs, the current market price is 24 million yuan per well, and due to its large equipment (the complete set of equipment includes an intermediate cantilever excavation device and a suspension device, weighing more than 300 tons), which greatly restricts the use of the fully mechanical prefabricated caisson; the prefabricated working well caisson construction method of this solution uses an excavator and a hydraulic backhoe excavation device to complete the excavation work, and realizes excavation through conventional excavation machinery and a simple hydraulic backhoe excavation device. Not only the energy consumption is greatly reduced, the equipment cost, the mechanical shift fee and the operator cost are greatly reduced, and the power consumption load is greatly reduced, but also the construction cost can be effectively reduced while ensuring the construction efficiency and safety.

[0009] In addition, the fully mechanical assembled caisson equipment of the prior art needs to be equipped with a power center tower (cable), a large-scale construction transformer, a supporting crawler crane of nearly 200 tons, etc. at the same time. It not only requires a larger construction site, but also only for arranging the central cantilever excavation mechanism and configuring the power center tower, etc. Compared with a method for constructing a caisson of an assembled working well in this solution, it requires an additional 7-10 days for the on-site installation period and 3-4 days for the demobilization period. Therefore, adopting a method for constructing a caisson of an assembled working well in this solution is also beneficial to shortening the construction period.

[0010] Preferably, it also includes the hoisting of precast shield pipe rings. In the step of excavating and sinking, a suspension device is used to hoist precast shield pipe rings above the base pipe ring in sequence and accurately sink them until the design elevation; then, a cast-in-place ring equal in height to the wellhead ring beam is poured in the wellhead above the precast shield pipe rings, and the cast-in-place ring and the wellhead ring beam are poured into one body. A method for constructing a caisson of an assembled working well in this solution uses precast shield pipe rings as the well wall, which can effectively improve the construction efficiency and further shorten the construction period compared with the conventional cast-in-place reinforced concrete on the ground.

[0011] Preferably, the same precast shield pipe ring includes a number of shield segments distributed circumferentially in sequence, and adjacent two shield segments of the same precast shield pipe ring are connected by bolts.

[0012] Preferably, it also includes a bottom sealing step. After the step of hoisting the precast shield pipe rings is completed, cast-in-place concrete is used for bottom sealing at the bottom of the working well.

[0013] Preferably, it also includes a foundation reinforcement step. Before the construction of the wellhead ring beam, the foundation reinforcement step is constructed. Specifically, A cement-soil mixing pile or a high-pressure jet grouting pile is used to reinforce the soil layer at the connection part between the tunnel and the working well.

[0014] Preferably, in the step of excavating and sinking, when the excavation depth of the working well is less than H1 meters, a P200 type excavator is used for excavation; when the excavation depth of the working well is H1 - H2 meters, H2 is greater than H1, a P200 long-arm excavator is used for excavation; when the excavation depth of the working well is greater than H2 meters, a telescopic arm grab excavator is used for excavation. In this way, it can ensure the smooth progress of the excavation operations at different depths in the working well.

[0015] Preferably, the base pipe ring includes three precast pipe rings distributed in sequence from bottom to top. The annular track includes two upper and lower tracks. One annular track is installed on the inner wall of the bottommost precast pipe ring, and the other annular track is installed on the inner wall of the uppermost precast pipe ring. In this way, it is ensured that the hydraulic backhoe excavating device can be stably installed on the two annular tracks, and the operation and excavation stability of the hydraulic backhoe excavating device are guaranteed.

[0016] Preferably, the precast pipe ring is made of reinforced concrete. Embedded steel plates are provided on the inner wall of the precast pipe ring, and the annular track is connected to the embedded steel plate by welding or bolts. In this way, the on-site installation of the annular track is facilitated.

[0017] Preferably, the base pipe ring includes at least one precast pipe ring distributed in sequence from bottom to top. The same precast pipe ring is an integrally formed structure, or the same precast pipe ring includes several shield segments distributed circumferentially in sequence. Adjacent shield segments of the same precast pipe ring are connected by bolts.

[0018] Preferably, the construction method of excavating and sinking uses the construction technology of non-drainage excavating and sinking. Compared with the conventional caisson design that requires the setting of a water-stop curtain and a strongly reinforced area at the bottom of the pit, resulting in an increase in construction investment and an extension of the construction period, the prefabricated working well caisson construction method of this solution uses the construction technology of non-drainage excavating and sinking. By keeping the water level in the well not lower than the elevation of the groundwater level outside the site, there is no need for a water-stop curtain, and the impact on the surrounding environment of the excavation is extremely small. Moreover, it can well solve the problem of the settlement impact of the conventional caisson on the surrounding environment of the soft soil foundation, ensuring the safety and comfort of the surrounding municipal facilities and buildings, and simply and efficiently promoting the application of the power tunnel in the complex urban environment.

[0019] The beneficial effects of the present invention are: it can not only effectively shorten the construction period, improve construction safety, and solve the problem of the insecurity of manual diving excavation; but also has good adaptability and can effectively reduce construction costs. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a construction method of a prefabricated working well caisson in the actual construction process of the present invention.

[0021] Figure 2 is Figure 1 a partial enlarged view of part A in

[0022] In the figure: Construction wellhead ring beam 1; Steel cutting edge 2; Base pipe ring 3, precast pipe ring 3.1, annular track 3.2; Excavator 4; Hydraulic backhoe excavating device 5, base 5.1, hydraulic backhoe bucket 5.2; Prefabricated shield pipe ring 6; Cast-in-situ ring 7. Specific embodiments

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments: Specific Example 1, as Figure 1 , Figure 2 shown, a construction method for the caisson of an assembled working shaft includes the following steps: Construct the wellhead ring beam 1, and the wellhead ring beam 1 is cast with reinforced concrete.

[0024] Install the ground steel cutting edge 2, and the steel cutting edge 2 is annular.

[0025] Install the base pipe ring 3 above the steel cutting edge 2. An annular track 3.2 is provided on the inner wall of the base pipe ring 3.

[0026] Install a hydraulic backhoe excavating device 5 on the annular track 3.2. The hydraulic backhoe excavating device 5 includes a base 5.1 that moves along the annular track 3.2, a driving mechanism for driving the movement of the base 5.1, and a hydraulic backhoe bucket 5.2 and / or a rotary cutting head provided on the base 5.1. The driving mechanism, the hydraulic backhoe bucket 5.2, and the rotary cutting head themselves are all prior arts. Therefore, this application does not elaborate on the specific methods and structures of the driving mechanism, the hydraulic backhoe bucket 5.2, and the rotary cutting head and other conventional technical means.

[0027] In one implementation manner of this embodiment, a hydraulic backhoe bucket 5.2 is provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is completed by the hydraulic backhoe excavating device 5.

[0028] In another implementation manner of this embodiment, a rotary cutting head is provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is completed by the rotary cutting head.

[0029] In the third implementation manner of this embodiment, a hydraulic backhoe bucket 5.2 and a rotary cutting head are provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is jointly completed by the hydraulic backhoe bucket 5.2 and the rotary cutting head.

[0030] Excavate and sink. Use an excavator 4 and a hydraulic backhoe excavating device 5 to excavate in the well, and the hydraulic backhoe excavating device 5 excavates under the steel cutting edge 2 through the hydraulic backhoe bucket 5.2.

[0031] Lifting of the precast shield pipe ring 6. During the excavation and sinking step, the precast shield pipe ring 6 is successively lifted above the base pipe ring 3 of the suspension device and accurately sunk until the design elevation. Then, a cast-in-place ring 7 with the same height as the wellhead ring beam 1 is poured in the wellhead above the precast shield pipe ring 6, and the cast-in-place ring 7 and the wellhead ring beam 1 are poured into one body.

[0032] In this embodiment, the excavation work in the construction method of the assembled working well caisson is completed by the cooperation of an excavator and a hydraulic backhoe excavation device 5. The main excavation work in the well is completed by the excavator. For the part below the steel cutting edge 2 where it is difficult to carry out excavation work by the excavator, there is no need to adopt manual excavation operation. The driving mechanism can be used to drive the base 5.1 to move along the annular track 3.2, thereby driving the hydraulic backhoe excavation device 5 to move along the annular track 3.2, and the excavation work below the steel cutting edge 2 is completed by the hydraulic backhoe excavation device 5, ensuring that there is no manual excavation operation throughout the process, thus improving the construction safety and solving the problem of unsafe manual diving excavation.

[0033] Compared with the conventional ground cast-in-place reinforced concrete and the manual excavation of the caisson, the work efficiency of the construction method of the assembled working well caisson in this embodiment is increased by 50%, which can effectively shorten the construction period, improve the construction safety, and solve the problem of unsafe manual diving excavation.

[0034] Compared with the conventional ground cast-in-place reinforced concrete, the construction method of the assembled working well caisson in this embodiment uses the precast shield pipe ring 6 as the well wall, which can effectively improve the construction efficiency and further shorten the construction period.

[0035] Compared with the existing full-mechanical assembled caisson construction method, there are high equipment rental and usage costs, especially equipment rental fees and labor costs. The current market price is 24 million yuan per well, and due to its large equipment (the complete set of equipment includes an intermediate cantilever excavation device and a suspension device, weighing more than 300 tons), the use of the full-mechanical assembled caisson is greatly restricted. In this embodiment, the construction method of the assembled working well caisson uses an excavator and a hydraulic backhoe excavation device 5 to complete the excavation work, and realizes the excavation through conventional excavation machinery and a simple hydraulic backhoe excavation device 5. Not only the energy consumption is greatly reduced, but also the equipment cost, mechanical shift cost, operator cost and power consumption load are greatly reduced. It can effectively reduce the construction cost while ensuring the construction efficiency and safety. In addition, the existing full-mechanical assembled caisson equipment also needs to be equipped with a power center tower (cable), a large-scale construction transformer, and a supporting crawler crane of nearly 200 tons. It not only requires a larger construction site, but also only for arranging the central cantilever excavation mechanism and configuring the power center tower, etc. Compared with the construction method of the assembled working well caisson in this embodiment, it requires an additional 7 - 10 days for the on-site installation period and 3 - 4 days for the demobilization period. Therefore, adopting the construction method of the assembled working well caisson in this embodiment is also beneficial to shortening the construction period.

[0036] In summary, compared with the current fully mechanical assembled caisson construction method, the construction efficiency of the caisson construction method for an assembled working well in this embodiment is increased by 25% (the on-site entry and exit time for a single well is reduced by 15 days); the cost is reduced by nearly 23 million yuan per well, within 80% (calculated according to the approximate budget of about 52 million yuan per well for the typical power tunnel working well that has been implemented currently); the requirements for the construction environment such as energy consumption and mud treatment are greatly reduced.

[0037] The caisson construction method for an assembled working well in this embodiment is not affected by the caisson type (both circular and rectangular working wells are applicable), has strong adaptability to size (applicable within an inner diameter of 22.0 m), strong adaptability to depth, and significantly saves investment. Therefore, it can be widely applied to various power tunnel construction scenarios of industrial tunnels (inner diameter of straight wells is 10.0 - 12.0 m, inner diameter of straight T-junction wells is 15.0 m) and double-cabin industrial tunnels (inner diameter of straight wells is 20.0 m, inner diameter of straight T-junction wells is 22.0 m) in complex urban environments, and is also suitable for scenarios such as municipal water supply and drainage working wells and subway ventilation wells.

[0038] Further, a caisson construction method for an assembled working well further includes a bottom sealing step. After completing the hoisting step of the precast shield pipe ring 6, cast-in-place concrete is used for bottom sealing at the bottom of the working well.

[0039] Further, in the earth excavation and sinking step, when the earth excavation depth of the working well is less than H1 meters, a P200 type excavator is used for earth excavation; when the earth excavation depth of the working well is H1 - H2 meters (H2 > H1), a P200 long-arm excavator is used for earth excavation; when the earth excavation depth of the working well is greater than H2 meters, a telescopic boom grab excavator is used for earth excavation. In this way, the earth excavation operations at different depths in the working well can be ensured to proceed smoothly. In this embodiment, H1 is 8 meters and H2 is 15 meters.

[0040] Further, the same precast shield pipe ring 6 includes a number of shield segments distributed in sequence circumferentially, and adjacent shield segments of the same precast shield pipe ring 6 are connected by bolts.

[0041] In this embodiment, the shield segments are trapezoidal, adjacent shield segments of the same precast shield pipe ring 6 are mutually embedded in a positive and negative manner, and waterproof rubber strips are arranged between adjacent shield segments. Shear pins are arranged between the upper and lower adjacent precast shield pipe rings 6.

[0042] The actual hoisting construction of the shield segments is accurately hoisted by a steel cable precise control suspension system. Through the steel cable precise control suspension system corresponding to the equally divided segments, centimeter-level caisson elevation control and high-precision horizontal and vertical control are achieved.

[0043] Further, the base pipe ring 3 includes at least one ring of precast pipe rings 3.1 distributed in sequence from bottom to top. The same precast pipe ring is an integrally formed structure; or the same precast pipe ring includes a number of shield segments distributed circumferentially in sequence, and adjacent shield segments of the same precast pipe ring are connected by bolts.

[0044] In this embodiment, as Figure 1 , Figure 2 shown, the base pipe ring 3 includes three rings of precast pipe rings 3.1 distributed in sequence from bottom to top. The annular track 3.2 includes two upper and lower tracks, one of which is installed on the inner wall of the bottommost ring of precast pipe rings, and the other is installed on the inner wall of the topmost ring of precast pipe rings. In this way, it is ensured that the hydraulic backhoe excavating device 5 can be stably installed on the two annular tracks 3.2, ensuring the stability of the operation and earth excavation function of the hydraulic backhoe excavating device 5.

[0045] In this embodiment, the precast pipe rings are made of reinforced concrete, and embedded steel plates are provided on the inner walls of the precast pipe rings. The annular track 3.2 is connected to the embedded steel plates by welding or bolts. In this way, it is convenient for the on-site installation of the annular track 3.2.

[0046] Specific Embodiment Two, as Figure 1 , Figure 2 shown, an assembled working well caisson construction method includes the following steps: Foundation reinforcement step, using cement-soil mixing piles or high-pressure jet grouting piles to reinforce the soil layer at the connection part between the tunnel and the working well; specifically, using cement-soil mixing piles or high-pressure jet grouting piles to reinforce the soil layer at the entrance and exit openings at the bottom of the working well connected to the tunnel.

[0047] Construct the wellhead ring beam 1, and the wellhead ring beam 1 is cast with reinforced concrete.

[0048] Install the ground steel cutting edge 2, and the steel cutting edge 2 is annular.

[0049] Install the base pipe ring 3 above the steel cutting edge 2. An annular track 3.2 is provided on the inner wall of the base pipe ring 3.

[0050] Install the hydraulic backhoe excavating device 5 on the annular track 3.2. The hydraulic backhoe excavating device 5 includes a base 5.1 that moves along the annular track 3.2, a driving mechanism for driving the base 5.1 to move, and a hydraulic backhoe bucket 5.2 and / or a rotary cutting head provided on the base 5.1. The driving mechanism, the hydraulic backhoe bucket 5.2 and the rotary cutting head itself are all prior arts, so this application does not elaborate on the specific methods and structures of the driving mechanism, the hydraulic backhoe bucket 5.2 and the rotary cutting head and other conventional technical means.

[0051] In one implementation of this embodiment, a hydraulic backhoe bucket 5.2 is provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is completed by the hydraulic backhoe excavation device 5.

[0052] In another implementation of this embodiment, a rotary cutting head is provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is completed by the rotary cutting head.

[0053] In the third implementation of this embodiment, a hydraulic backhoe bucket 5.2 and a rotary cutting head are provided on the base 5.1. During actual excavation work, the excavation work under the steel cutting edge 2 is jointly completed by the hydraulic backhoe bucket 5.2 and the rotary cutting head.

[0054] For excavation and sinking, an excavator 4 and a hydraulic backhoe excavation device 5 are used to excavate in the well. Among them, the hydraulic backhoe excavation device 5 excavates under the steel cutting edge 2 through the hydraulic backhoe bucket 5.2. In this embodiment, the construction of excavation and sinking adopts the construction technology of non-drainage excavation and sinking.

[0055] Lifting of precast shield pipe rings 6. During the excavation and sinking step, the precast shield pipe rings 6 are successively lifted above the base pipe ring 3 of the suspension device and accurately sunk until the design elevation. Then, a cast-in-situ ring 7 with the same height as the wellhead ring beam 1 is poured in the wellhead above the precast shield pipe ring 6, and the cast-in-situ ring 7 and the wellhead ring beam 1 are cast as a whole.

[0056] In the excavation work of the construction method of the assembled working well caisson in this embodiment, the excavation work is completed by the cooperation of the excavator and the hydraulic backhoe excavation device 5. The main excavation work in the well is completed by the excavator. For the part under the steel cutting edge 2 that is difficult to excavate by the excavator, there is no need to adopt manual excavation operation. The base 5.1 can be driven to move along the annular track 3.2 through the driving mechanism, thereby driving the hydraulic backhoe excavation device 5 to move along the annular track 3.2. The excavation work under the steel cutting edge 2 is completed by the hydraulic backhoe excavation device 5, ensuring that there is no need for manual excavation operation throughout the process, thereby improving the construction safety and solving the problem of unsafe manual diving excavation.

[0057] Compared with the conventional caisson design that requires the setting of a waterproof curtain and a strong reinforcement area at the bottom of the pit, resulting in an increase in construction investment and an extension of the construction period, the construction method of the assembled working well caisson in this embodiment adopts the construction technology of non-drainage excavation and sinking. By keeping the water level in the well not lower than the elevation of the groundwater level outside the site, there is no need for a waterproof curtain, and the impact on the surrounding environment of the excavation is extremely small. Moreover, it can well solve the problem of the settlement impact of the conventional caisson on the surrounding environment of the soft soil foundation, ensuring the safety and comfort of the surrounding municipal facilities and buildings, and simply and efficiently promoting the application of the power tunnel in the complex urban environment.

[0058] Compared with the conventional cast-in-situ reinforced concrete on the ground and the manual excavation of caissons, the work efficiency of the caisson construction method for an assembled working well in this embodiment is increased by 50%, which can effectively shorten the construction period, improve construction safety, and solve the problem of unsafe manual underwater excavation.

[0059] Compared with the conventional cast-in-situ reinforced concrete on the ground, the caisson construction method for an assembled working well in this embodiment uses precast shield pipe rings 6 as the well wall, which can effectively improve the construction efficiency and further shorten the construction period.

[0060] Compared with the existing full-mechanical assembled caisson construction method, there are high equipment rental and usage costs, especially equipment rental fees and labor fees. The current market price is 24 million yuan per well. And due to its large equipment (the complete set of equipment includes a middle cantilever excavation device and a suspension device, weighing more than 300 tons), the use of the full-mechanical assembled caisson is greatly restricted. The caisson construction method for an assembled working well in this embodiment uses an excavator and a hydraulic backhoe excavation device 5 to complete the excavation operation, and realizes the excavation through conventional excavation machinery and a simple hydraulic backhoe excavation device 5. Not only the energy consumption, equipment cost, mechanical shift fee, and operator fee are greatly reduced, but also the power consumption load is greatly reduced. It can effectively reduce the construction cost while ensuring the construction efficiency and safety. In addition, the full-mechanical assembled caisson equipment of the existing technology also needs to be equipped with a power center tower (cable), a large-scale construction transformer, and a supporting crawler crane of nearly 200 tons. It not only requires a larger construction site, but also only the work of arranging the center cantilever excavation mechanism and configuring the power center tower, etc. Compared with the caisson construction method for an assembled working well in this embodiment, it requires an additional 7 - 10 days for the on-site installation period and 3 - 4 days for the off-site period. Therefore, using the caisson construction method for an assembled working well in this embodiment is also beneficial to shortening the construction period.

[0061] In summary, compared with the current full-mechanical assembled caisson construction method, the work efficiency of the caisson construction method for an assembled working well in this embodiment is increased by 25% (the on-site and off-site time of a single well is reduced by 15 days); the cost is reduced by nearly 23 million yuan per well, within 80% (calculated according to the budget estimate of about 52 million yuan per well for the typical power tunnel working well that has been implemented currently); the requirements for the construction environment such as energy consumption and mud treatment are greatly reduced.

[0062] A construction method for the caisson sinking of an assembled working well in this embodiment is not affected by the type of caisson (both circular and rectangular working wells are applicable), has strong adaptability to size (applicable within an inner diameter of 22.0 m), strong adaptability to depth, and significantly saves investment. Therefore, it can be widely applied to various power tunnel construction scenarios of industrial tunnels (inner diameter of straight wells is 10.0 - 12.0 m, inner diameter of straight T-junction wells is 15.0 m) and double-cabin industrial tunnels (inner diameter of straight wells is 20.0 m, inner diameter of straight T-junction wells is 22.0 m) in complex urban environments. It is also suitable for scenarios such as municipal water supply and drainage working wells and subway ventilation wells.

[0063] Furthermore, a construction method for the caisson sinking of an assembled working well further includes a bottom sealing step. After completing the hoisting step of the precast shield pipe ring 6, cast-in-place concrete is used for bottom sealing at the bottom of the working well.

[0064] Furthermore, in the earth excavation and sinking step, when the earth excavation depth of the working well is less than H1 meters, a P200 type excavator is used for earth excavation; when the earth excavation depth of the working well is H1 - H2 meters (H2 > H1), a P200 long-arm excavator is used for earth excavation; when the earth excavation depth of the working well is greater than H2 meters, a telescopic arm grab excavator is used for earth excavation. In this way, the earth excavation operations at different depths in the working well can be ensured to proceed smoothly. In this embodiment, H1 is 8 meters and H2 is 15 meters.

[0065] Furthermore, the same precast shield pipe ring 6 includes a number of shield segments distributed circumferentially in sequence. Adjacent shield segments of the same precast shield pipe ring 6 are connected by bolts.

[0066] In this embodiment, the shield segments are trapezoidal. Adjacent shield segments of the same precast shield pipe ring 6 are mutually embedded in a positive and negative manner, and waterproof rubber strips are provided between adjacent shield segments. Shear-resistant pins are provided between the upper and lower adjacent precast shield pipe rings 6.

[0067] During the actual hoisting construction of the shield segments, a steel cable precise control suspension system is used for precise hoisting. Through the steel cable precise control suspension system corresponding to the equally divided segments, centimeter-level caisson elevation control and high-precision horizontal and vertical control are achieved.

[0068] Furthermore, the base pipe ring 3 includes at least one ring of precast pipe rings 3.1 distributed sequentially from bottom to top. The same precast pipe ring is an integrally formed structure; or the same precast pipe ring includes a number of shield segments distributed circumferentially in sequence, and adjacent shield segments of the same precast pipe ring are connected by bolts.

[0069] In this embodiment, as Figure 1 、 Figure 2As shown, the base pipe ring 3 includes three precast pipe rings 3.1 distributed in sequence from bottom to top. The annular track 3.2 includes two upper and lower tracks, one of which is installed on the inner wall of the bottommost precast pipe ring, and the other is installed on the inner wall of the uppermost precast pipe ring. In this way, it is ensured that the hydraulic backhoe excavator 5 can be stably installed on the two annular tracks 3.2, ensuring the stability of the operation and earth excavation function of the hydraulic backhoe excavator 5.

[0070] In this embodiment, the precast pipe ring is made of reinforced concrete, and embedded steel plates are provided on the inner wall of the precast pipe ring. The annular track 3.2 is connected to the embedded steel plate by welding or bolts. In this way, it is convenient for the on-site installation of the annular track 3.2.

[0071] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments according to the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A construction method for the sinking of an assembled working well, characterized in that, It includes the following steps: Construct the wellhead ring beam; Install the ground steel cutting edge; Install the base pipe ring above the steel cutting edge, and an annular track is provided on the inner wall of the base pipe ring; Install a hydraulic backhoe excavating device on the annular track, which includes a base moving along the annular track, a driving mechanism for driving the base to move, and a hydraulic backhoe bucket and / or a rotary cutting head arranged on the base; Excavate and sink. Use an excavator and a hydraulic backhoe excavating device to excavate soil in the well. Among them, the hydraulic backhoe excavating device excavates the soil under the steel cutting edge through the hydraulic backhoe bucket and / or the rotary cutting head.

2. The construction method of the fabricated working well by open caisson according to claim 1, characterized in that, It also includes the hoisting of precast shield pipe rings. During the excavation and sinking step, use a suspension device to hoist precast shield pipe rings above the base pipe ring in sequence and accurately sink them until the design elevation; Then, pour a cast-in-place ring equal in height to the wellhead ring beam in the wellhead above the precast shield pipe ring, and the cast-in-place ring and the wellhead ring beam are cast as a whole.

3. A construction method for a prefabricated working well caisson according to claim 2, characterized in that, The same precast shield pipe ring includes several shield segments distributed circumferentially in sequence, and adjacent shield segments of the same precast shield pipe ring are connected by bolts.

4. A construction method for a fabricated working well caisson according to claim 2 or 3, characterized in that It also includes a bottom sealing step. After completing the hoisting step of the precast shield pipe ring, cast-in-place concrete is used for bottom sealing at the bottom of the working well.

5. A construction method for a prefabricated working well by open caisson construction, characterized in that, It also includes a foundation reinforcement step, Before constructing the wellhead ring beam, construct the foundation reinforcement step. Specifically, Use a cement-soil mixing pile or a high-pressure jet grouting pile to reinforce the soil layer at the connection part between the tunnel and the working well.

6. A construction method for a prefabricated working well caisson according to claim 1 or 2 or 3, characterized in that, During the excavation and sinking step, when the excavation depth of the working well is less than H1 meters, a P200 type excavator is used for excavation; when the excavation depth of the working well is H1 - H2 meters, H2 is greater than H1, a P200 long-arm excavator is used for excavation; when the excavation depth of the working well is greater than H2 meters, a telescopic arm grab excavator is used for excavation.

7. A construction method for a prefabricated working well caisson according to claim 1 or 2 or 3, characterized in that, The base pipe ring includes three precast pipe rings distributed from bottom to top in sequence. The annular track includes two upper and lower tracks. One annular track is installed on the inner wall of the bottommost precast pipe ring, and the other annular track is installed on the inner wall of the topmost precast pipe ring.

8. A construction method for a fabricated working well caisson according to claim 7, characterized in that, The precast pipe ring is made of reinforced concrete, and embedded steel plates are provided on the inner wall of the precast pipe ring. The annular track is welded or bolted to the embedded steel plate.

9. A construction method for a prefabricated working well caisson according to claim 1 or 2 or 3, characterized in that, The base pipe ring includes at least one precast pipe ring distributed from bottom to top in sequence. The same precast pipe ring is an integrally formed structure, or the same precast pipe ring includes several shield segments distributed circumferentially in sequence, and adjacent shield segments of the same precast pipe ring are connected by bolts.

10. A construction method for the sinking of a prefabricated working well, according to claim 1 or 2 or 3, characterized in that The excavation and sinking construction adopts the non-drainage excavation and sinking construction technology.

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