Excavation robot for caisson construction, caisson construction system, and caisson construction method

Abstract

Provided are a digging robot, a caisson construction system and a caisson construction method. The digging robot comprises a base installed on a fixed position in a shaft structure, a support assembly and a movable arm. The support assembly is installed to the base and can rotate relative to the base about a first vertical axis. The movable arm is installed to the support assembly and can rotate relative to the support assembly about a second vertical axis. The second vertical axis is parallel to the first vertical axis and is spaced apart from the first vertical axis by a predetermined distance. The movable arm can also swing relative to the support assembly about a first horizontal axis. The end of the movable arm is provided with a digging part configured to dig soil in the shaft structure within a predetermined contour in response to the digging robot running a predetermined program. According to the scheme of the present application, the digging robot is suitable for undrained construction, is flexible to operate, can adapt to shafts with any cross-sectional shape, and the frequently moving parts have small weight, which can slow down wear and tear and prolong service life.

Description

Technical Field

[0001] This invention relates generally to the field of caisson construction technology, and more specifically, to an excavation robot, a caisson construction system, and a caisson construction method. Background Technology

[0002] Tunnels in underground rail transit systems such as subways typically include vertical tunnels (also known as shafts) leading to the surface to meet requirements for ventilation and smoke extraction. Traditionally, vertical tunnel construction involved excavating downwards from the ground and reinforcing it with brickwork. With the widespread use of concrete, the caisson method emerged. This method involves prefabricating a shaft at ground level and, under the protection of the prefabricated shaft, using the shaft's own weight combined with excavation work within the shaft to overcome wall friction and cutting edge resistance, lowering the shaft to the designed elevation before finally sealing the bottom.

[0003] However, traditional caisson construction methods have drawbacks such as long construction periods and high risks. For example, the structure and composition of geological formations are often non-uniform, resulting in constantly changing resistances and their circumferential distribution at different depths of the caisson. This means that the resultant force driving the caisson to sink varies at different depths, and even at the same depth, the resultant force is unevenly distributed circumferentially, making the caisson prone to sudden sinking or tilting during caisson descent.

[0004] Furthermore, the caisson method is poorly suited for formations with high water content. On the one hand, water-bearing formations exacerbate the frequency and severity of the aforementioned hazards. On the other hand, to facilitate operations such as excavation within the caisson, additional waterproofing and drainage measures are required, further extending the construction period, increasing construction costs, and potentially causing subsidence of the surrounding soil due to drainage. Therefore, it is desirable to construct caissons without drainage to minimize these problems. However, the presence of groundwater within the caisson restricts the visibility of ground personnel, making it impossible to accurately assess the situation below the water surface. This presents new challenges for caisson construction—especially soil extraction. Some solutions utilize excavating robots installed within the caisson for remote-controlled excavation. However, the applicability of these existing excavating robots is limited; for example, they may only be suitable for circular caissons, and are difficult to apply to other shapes. In addition, these existing excavating robots suffer from poor flexibility and are prone to damage due to frequent reciprocating rotations.

[0005] In summary, there is a need to provide a caisson construction system to at least partially solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an excavation robot suitable for caisson construction under non-drainage conditions. This excavation robot has excellent flexibility, wider adaptability to caisson shapes, and its frequently moving parts are lightweight, which can reduce wear and extend service life.

[0007] According to one aspect, the excavating robot includes: The base is installed at the fixed position within the well shaft structure; A support assembly, which is mounted to the base and configured to rotate relative to the base about a first vertical axis; A movable arm is mounted to the support assembly and configured to rotate relative to the support assembly about a second vertical axis, wherein the second vertical axis is parallel to the first vertical axis and spaced laterally by a predetermined distance. The movable arm is also configured to swing relative to the support assembly about a first transverse axis. The end of the movable arm is provided with a digging part, which is configured to dig the soil within the well structure within a predetermined contour in response to the digging robot running a predetermined program.

[0008] In some embodiments, the angle of the first transverse axis relative to the plane passing through both the first and second vertical axes changes as the movable arm rotates about the second vertical axis.

[0009] In some embodiments, the support assembly is also configured to move the movable arm relative to the base along the first vertical axis.

[0010] In some embodiments, the movable arm is provided with a telescopic structure, allowing its length to be variable. The movable arm includes at least two stages of telescopic structure, preferably three stages.

[0011] In some embodiments, the excavating unit is configured as a cutter suction pump, which is connected to the end of the movable arm via a hinged structure.

[0012] In some embodiments, the excavating robot is configured to apply polar coordinate variable control to adjust the position of the excavating part, such that the excavating part can traverse the area within the predetermined contour, wherein the polar coordinates are defined by the projection of the first vertical axis onto a plane perpendicular to the first vertical axis as the pole, and the ray drawn from the projection onto the plane perpendicular to the first vertical axis as the polar axis, wherein at each angular position of the support assembly, the swing plane of the movable arm is parallel to or perpendicular to the polar axis.

[0013] In some embodiments, the well structure is provided with a cross beam connected to the sidewall, the first vertical axis passes through the center of the cross beam, and one of the beams defines the polar axis.

[0014] In some embodiments, the predetermined contour is divided into four quadrants by the cross beam, wherein the movement trajectory of the excavator in two adjacent quadrants is symmetrical with respect to the beam separating the two quadrants.

[0015] According to another aspect, a caisson construction system is also provided, which includes: The assist unit includes a plurality of hydraulic cylinders arranged around the well shaft structure of the caisson, the hydraulic cylinders being directly or indirectly connected to the ground base for providing downforce and / or lifting force to the well shaft structure; and the excavation robot as described above.

[0016] According to another aspect, a caisson construction method is also provided, the caisson construction method comprising: Step A: Set up an assist unit, which includes multiple hydraulic cylinders that surround the designed position of the caisson and are connected to the ground base; Step B: Set up the first section of the well shaft, connect the assist unit to the first section of the well shaft, lower the first section of the well shaft to the predetermined position, and simultaneously perform soil removal operation; Step C: Set up a new section of the well shaft, connect the new section of the well shaft to the uppermost well shaft that has been sunk to the position, disconnect the assist unit from the uppermost well shaft that has been sunk to the position and connect it to the new section of the well shaft, sink the new section of the well shaft to the predetermined position, and simultaneously perform soil removal operation; Step D, repeat step C, until the caisson reaches the designed depth; In step E, steps C and D, after a predetermined number of wells have been lowered into place, the excavation robot described above is installed, and the excavation robot is used to perform the soil extraction operation in subsequent steps. Step F: Perform a bottom sealing operation on the first section of the wellbore.

[0017] In some embodiments, a pressure-bearing seat is detachably mounted on the end of the extension rod of the hydraulic cylinder, and the hydraulic cylinder is connected to the well casing through the pressure-bearing seat. In step C, the step of disconnecting the assist unit from the uppermost well casing that has been lowered into place and connecting it to the new well casing section further includes: Step C1: Use a support base to vertically support the pressure-bearing seat connected to the uppermost shaft that has already been lowered into place. Step C2: Remove the pressure-bearing seat, which is connected to the uppermost shaft that has been lowered into place, from the hydraulic cylinder. Step C3: Raise the extension rod of the hydraulic cylinder to a high position, install the new pressure bearing seat, and connect the new pressure bearing seat to the new section of the well barrel.

[0018] In some embodiments, the pressure-bearing seat is rotatably mounted on the end of the extension rod via a hinged structure about a second transverse axis.

[0019] In some embodiments, the caisson construction method is carried out without actively lowering the groundwater level of the stratum where the caisson is located.

[0020] In some embodiments, the excavating robot is equipped with a centering structure, and in step E, the excavating robot is installed in place below the water surface.

[0021] In some embodiments, the outer surface of the first section of the well casing is provided with a grouting port, and the first section of the well casing and each subsequent section of the well casing include interconnected grouting pipelines. Steps B and C further include: During the sinking of the well, grout is injected between the well and the soil through the grouting pipeline and the grouting port.

[0022] In some embodiments, step B further includes installing a cutting edge at the lower end of the first section of the wellbore.

[0023] In some embodiments, the cross-section of the well shaft is circular, elliptical, rectangular, or trapezoidal.

[0024] According to the present invention, the excavation robot is suitable for caisson construction operations under non-drainage conditions, and is flexible in operation, capable of adapting to well casings with circular, elliptical, or arbitrary convex polygonal cross-sectional shapes. Furthermore, the frequently moving parts are lightweight, which reduces wear and extends service life. Attached Figure Description

[0025] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale. Figure 1 This is a three-dimensional schematic diagram of a caisson construction system according to a preferred embodiment of the present invention; Figure 2 yes Figure 1 A vertical cross-sectional schematic diagram of the caisson construction system shown; Figure 3 This is a front view of an excavating robot according to a preferred embodiment of the present invention; Figure 4 yes Figure 3 A 3D view of the excavating robot shown; Figure 5 yes Figure 3 The diagram shows the sweeping range of the excavating robot. Figures 6A to 6C yes Figure 3 The diagram shown illustrates the process of a digging robot performing a digging operation within one quadrant. Figure 7 yes Figure 1 A three-dimensional schematic diagram of the assist unit of the caisson construction system shown; and Figure 8 This is a schematic flowchart of a caisson construction method according to a preferred embodiment of the present invention. Detailed Implementation

[0026] Now, with reference to the accompanying drawings, specific embodiments of the present invention will be described in detail. The embodiments described herein are merely preferred embodiments of the invention; those skilled in the art can conceive of other ways to implement the invention based on these preferred embodiments, and such other ways also fall within the scope of the invention.

[0027] This invention provides a construction system for the caisson method, used to assist the caisson structure in sinking into place in a controlled manner. Preferred embodiments of the invention are described below with reference to the accompanying drawings.

[0028] like Figure 1 and Figure 2 As shown, the construction system 1 may include an assist unit 10 and an excavation unit 20. The assist unit 10 includes multiple hydraulic cylinders arranged around the well shaft structure 100 of the caisson. These hydraulic cylinders can be connected (or engaged) with the well shaft structure 100 to provide downward pressure to assist its sinking, or, in the event of sudden sinking or tilting, all or some of the hydraulic cylinders provide lifting force, effectively controlling the attitude and sinking speed of the well shaft structure 100 to achieve smooth sinking. Preferably, the ground G around the caisson can be reinforced, serving as anchor points for the assist unit 10 to apply force. For example, in the illustrated embodiment, reinforcement is achieved using driven piles 15, which also serve as anchor points for applying force. In another embodiment, reinforcement can also be achieved by pouring concrete into the ground. These reinforcement structures used as anchor points for applying force can be referred to as ground bases.

[0029] The well shaft structure 100 can be composed of multiple well shaft sections connected together. Each well shaft section can be assembled from several segments. The segments constituting the well shaft can be prefabricated in a factory and transported to the construction site for assembly. During actual construction, the first well shaft section can be assembled on the ground and connected (or joined) to the assist unit 10. Using the weight of the well shaft and with the assistance of the assist unit 10 and soil removal operations, the first well shaft section is lowered below the ground surface. Then, the assist unit 10 is disconnected (or disengaged) from the first well shaft section. The next well shaft section is then assembled, connected to the first well shaft section that has been lowered to the predetermined position, and connected to the assist unit 10, and the lowering operation is performed again. The above steps are repeated for each subsequent well shaft section until the caisson reaches the designed depth.

[0030] Preferably, a cutting edge 101 can be provided at the bottom of the first section of the well casing. This cutting edge, made of a metal material such as steel, has a narrower bottom side compared to the thickness of the well casing, thus increasing the pressure exerted by the well casing structure 100 on the soil and facilitating smoother sinking. Additionally, for each section of the well casing, multiple axially extending grouting pipes 102 can be provided at circumferential intervals. For the first section of the well casing, the grouting pipes 102 open on their sides near the bottom. For the other sections, the grouting pipes 102 are axially continuous, and the grouting pipes 102 of adjacent sections are fluidly connected. Grouting can be performed on the ground through the grouting pipes 102 to form a grout film on the outer wall of the well casing structure 100, which helps reduce the friction between the well casing structure 100 and the soil during the sinking process, facilitating smoother sinking.

[0031] Figure 7 A single assist unit 10 is shown, wherein the hydraulic cylinder 11 is mounted on a ground base (e.g., via a support column 12). Figure 2 The hydraulic cylinder 11 is extendable along the vertical telescopic axis AX5 to connect / disconnect with each section of the well shaft structure 100 and provide downforce or lifting force. For ease of force application, the extended end of the hydraulic cylinder 11 is provided with a bearing seat 14 having a mating surface 141 for connection with the well shaft. The mating surface 141 allows for a larger contact area with the well shaft, resulting in better force transmission between the hydraulic cylinder 11 and the well shaft. Preferably, the mating seats, such as steel structures, can be embedded during factory prefabrication or on-site casting of the segments. During well shaft assembly, each mating seat is positioned to correspond to the corresponding assist unit 10 for connection with the hydraulic cylinder 11. Preferably, the mating surface 141 of the bearing seat 14 is detachably connected to the well shaft's mating seat by bolts.

[0032] Continue to refer to Figure 7Preferably, the pressure seat 14 is rotatably disposed at the extended end of the hydraulic cylinder 11 about a second transverse rotation axis AX4. For example, the pressure seat 14 can be connected to the extended end of the hydraulic cylinder 11 via a hinged structure. This hinged structure defines the second transverse rotation axis AX4. In this way, when the movement of the well shaft structure 100 and the hydraulic cylinder 11 is asynchronous, the pressure seat 14 can rotate slightly about the second transverse rotation axis AX4 to counteract the asynchronous movement between the well shaft structure 100 and the hydraulic cylinder 11, thereby avoiding the generation of unintended forces between the well shaft structure 100 and the hydraulic cylinder 11 that could damage the connection due to the asynchronous movement. Furthermore, preferably, the pressure seat 14 is also detachably disposed at the extended end of the hydraulic cylinder 11. In this way, during the pressing process, after a section of the well shaft has sunk into place, the pressure seat 14 can be pressed against a support on the ground, simultaneously disengaging the connection between the pressure seat 14 and the hydraulic cylinder 11. The support base can provide support for the sunken well casing as a whole, preventing it from sinking uncontrollably due to gravity after the force applied by the assist unit 10 is released. Then, the hydraulic cylinder 11 can be raised and connected to the new pressure seat 14 for connection with the newly assembled well casing, making the construction process more flexible.

[0033] When the first or several sections of the shaft are sinking, the soil inside the shaft is not far from the ground, and soil can be removed by manual excavation or by using a long-arm excavator positioned on the ground. However, as the number of shafts sinks underground increases, the distance between the soil inside the shaft and the ground increases, making manual excavation or ground-based excavation methods unsuitable. At this point, an excavation unit 20 can be installed inside the shaft structure 100, for example, fixed to the first shaft section, and soil can be removed using the excavation unit 20. In this way, the excavation unit 20 can sink synchronously with the shaft structure 100.

[0034] According to the present invention, the excavation unit 20 can be in the form of a robot, that is, the excavation unit 20 is configured to automatically or semi-automatically (e.g., some control requires manual assistance from the operator) perform soil removal operations under the action of an actuator in response to a controller running a predetermined program. For example, the excavation unit 20 includes necessary components such as sensors, a controller, and actuators for realizing robot functions. The sensors can be used to sense terrain information at the bottom of the well structure 100, sense information reflecting the working state of the excavation unit 20, etc., and send the sensed information to the controller. The controller stores a predetermined program, which can run the predetermined program, receive information from the sensors, generate corresponding control commands, and send the control commands to the actuators. The actuators perform corresponding actions based on the received control commands to complete the excavation task. It is understood that sensors can compensate to some extent for the limitation of operator visibility caused by groundwater by sensing environmental information; therefore, the excavation unit 20, constructed as a robot, is particularly suitable for performing soil removal operations within the well structure 100 under non-drainage conditions. Based on this, the excavation unit can also be called an excavation robot.

[0035] like Figure 3 and Figure 4 As shown, the excavation unit 20 may include a base 21, a support assembly 22, and a movable arm 23. The base 21 may be pre-installed within the shaft structure 100 and sink synchronously with it, serving as the installation foundation for subsequent installation of other parts of the excavation unit 20. In some embodiments, a cross beam connected to the side wall may be provided within the shaft structure 100 as a fixing point, and the base 21 may be fixed to the cross beam, preferably located at the intersection of the cross beams. To bring the excavation unit 20 as close as possible to the soil to be excavated, the cross beam may be located within the first section of the shaft, preferably at its bottom.

[0036] The movable arm 23 is mounted to the support assembly 22, and its end is provided with a digging part 231. The support assembly 22 is mounted to the base 21, which serves as the main body of the digging unit 20. It acts as the mounting base for the movable arm 23 and also houses components such as controllers used to implement robot functions. In some embodiments, the support assembly 22 is detachably mounted to the base 21. To ensure accurate installation of the support assembly 22 with the correct orientation, a matching alignment structure can be provided on the support assembly 22 and the base 21. The support assembly 22 can rotate relative to the base 21 about a first vertical axis AX1 to adjust the position of the movable arm 23 and its end digging part 231 within the well structure 100. Furthermore, the movable arm 23 can rotate relative to the support assembly 22 about a second vertical axis AX2. The second vertical axis AX2 is parallel to the first vertical axis AX1 and is spaced a predetermined distance laterally. The movable arm 23 can also swing relative to the support assembly 22 in a vertical plane about a first transverse axis AX3.

[0037] like Figure 5 As shown, in the above structure, the movable arm 23 and its end-digging section 231 actually have two centers of rotation. When the movable arm 23 rotates together with the support assembly 22 around the first vertical axis AX1, the angular position of the entire digging unit 20 within the shaft structure 100 can be adjusted. When the movable arm 23 rotates around the second vertical axis AX2, the position of the movable arm 23 and its end-digging section 231 can be finely adjusted within a small range while the angular position of the support assembly 22 is fixed, thereby improving the adjustment flexibility of the digging unit 20 and enabling it to adapt to more shaft structures 100 shapes other than circular, such as shaft structures with arbitrary cross-sections such as rectangular, trapezoidal, elliptical, or convex polygonal shapes.

[0038] Preferably, in some embodiments, the excavating unit 20 further includes a rotary seat 24, which is rotatably mounted to the support assembly 22 about a second vertical axis AX2, and also has a swing drive. The movable arm 23 is connected to the rotary seat 24, and on the one hand, the rotary seat 24 as a whole rotates about the second vertical axis AX2, and on the other hand, the swing drive enables it to swing about a first transverse axis AX3. In other words, when the movable arm 23 rotates about the second vertical axis AX2, the rotary seat 24 also rotates synchronously, and when the movable arm 23 swings about the first transverse axis AX3, the rotary seat 24 remains essentially stationary. Therefore, a plane is defined that passes through both the first vertical axis AX1 and the second vertical axis AX2. When the movable arm 23 rotates about the second vertical axis AX2, the angle of the first transverse axis AX3 relative to this plane changes with the rotation. This arrangement allows the excavating part 231 to reach every point within the excavation area in a more flexible manner, that is, the excavating part 231 can traverse the area within the well shaft structure 100. The swing drive can specifically be a hydraulic cylinder or a motor or other drive mechanism.

[0039] Preferably, the trajectory control of the excavator 231 can be achieved using the polar coordinate variable control method. For example... Figures 6A to 6CAs shown, the cross beam used to install the excavation unit 20 can be a cross beam. Accordingly, the cross beam divides the area within the shaft structure 100 corresponding to the excavation unit 20 into four parts, which can be considered as four quadrants. When viewed from above, for the first quadrant, the polar coordinates can be defined by taking the projection of the first vertical axis AX1 onto a plane perpendicular to it as the pole, and a ray emanating from that pole as the polar axis (e.g., one of the beams of the cross beam as the polar axis). During the excavation and soil removal task, the angular position of the support assembly 22 is adjusted by rotating it around the first vertical axis AX1 relative to the polar axis between 0-90°. This adjustment simultaneously changes the distance of the second vertical axis AX2 relative to the polar axis. Then, the movable arm 23 can be rotated around the second vertical axis AX2 so that the first transverse axis AX3 is perpendicular to the polar axis. At this time, the swing plane of the movable arm 23 is parallel to the polar axis. Furthermore, the movable arm 23 can be driven to swing, allowing the digging unit 231 to sweep the area corresponding to the position of the second vertical axis AX2 with a trajectory parallel to the polar axis. After sweeping at one position is completed, the position of the second vertical axis AX2 can be adjusted by rotating the support assembly 22 around the first vertical axis AX1 to the next angular position, as described above, and the sweeping operation can be repeated at the next position. This process is repeated until the entire first quadrant is swept. Of course, in another embodiment, the movable arm 23 can also be rotated around the second vertical axis AX2 so that the first transverse axis AX3 is parallel to the polar axis to complete the sweeping at each angular position. In this case, the swing plane of the movable arm 23 is perpendicular to the polar axis. It can be seen that in this scheme, the support assembly 22 is only used to adjust the angular position, and more fine adjustments are achieved through the frequent rotation and swinging of the movable arm 23. That is, the movement frequency of the support assembly 22 is much lower than that of the movable arm 23. It is understandable that, given the large weight of the support assembly 22, reducing its movement frequency helps to reduce the wear of components used for rotating around the first vertical axis AX1, thus extending the service life of the excavation unit 20 to some extent.

[0040] Preferably, adjacent quadrants in the four quadrants divided by the cross beam are substantially symmetrical. Therefore, the movement trajectory of the excavator 231 in two adjacent quadrants is axially symmetrical with respect to the beam separating the two quadrants. In this way, only one quadrant needs to be programmed with a control program. For other quadrants, the same control program can be applied by mirroring the coordinate points symmetrically, thus greatly simplifying the complexity of movement trajectory control.

[0041] Preferably, refer to Figure 3In some embodiments, the support assembly 22 is configured to drive the movable arm 23 to move up and down along the first vertical axis AX1. This configuration decouples the two levels of digging depth and digging plane operation. After completing a horizontal cross-section sweep excavation, the digging unit 20 descends by one step through the up-and-down movement of the support assembly 22. Then, it can complete another horizontal cross-section sweep excavation at that depth using the same horizontal working trajectory. The horizontal working trajectory remains consistent at different depths without needing to recalculate the horizontal trajectory due to descent. This reduces the working path planning of the digging unit 231 from a three-dimensional problem to a two-dimensional problem, making control simpler and more reliable. Furthermore, the movable arm 23 is preferably constructed with at least two telescopic stages, such as a three-stage telescopic arm. Thus, the length of the movable arm 23 is variable, adjusting as it swings around the first transverse axis AX3, keeping the digging unit 231 sweeping within the horizontal plane. The multi-stage telescopic structure also allows the movable arm 23 to have sufficient length to more easily reach the farthest points of the polygon's corners and equidistant poles.

[0042] In some embodiments, the excavating section 231 is configured as a cutter suction pump, which is hinged to the end of the movable arm 23 and fluidly connected to the operating equipment on the ground via a delivery pipeline. The hinged structure allows for fine-tuning of the angle of the excavating section 231 relative to the movable arm 23, enabling the excavating section 231 to expand its reach even when the movable arm 23 is at its dead point (limit point). For the excavating section 231 configured as a cutter suction pump, an exemplary operation could be as follows: as the cutter suction pump sweeps across a certain range in the horizontal plane with the swing of the movable arm 23, its rotating cutter head cuts the soil. The cut soil mixes with water to form slurry, which is then transported to the ground via a delivery pipeline. After filtration, the water is returned to the caisson, while the filtered soil remains on the ground. In this way, the water level in the caisson does not drop significantly. Because drainage is unnecessary, the risk of soil subsidence is greatly reduced, thereby minimizing disturbance to surrounding buildings. It is understood that the function of the excavation unit is to separate and remove the soil from the strata within the well structure. Therefore, it is not limited to a cutter pump; any embodiment capable of separating and removing the soil to achieve the soil extraction function can be used as an excavation unit.

[0043] Figure 8A flowchart illustrating the caisson construction using the aforementioned caisson construction system is shown. After preliminary preparations (such as site leveling and pile location marking) are completed, the foundation pit is first excavated at the designed construction location of the caisson. This step can be achieved through manual excavation, ground machinery excavation, etc. Then, or simultaneously, multiple hydraulic cylinders constituting the assist unit are connected to the pre-prepared ground base (e.g., foundation piles). Next, the first section of the caisson is installed at the caisson location, and the hydraulic cylinders of the assist unit are connected to the first section of the caisson. Utilizing the downward pressure or lifting force provided by the assist unit and the weight of the first section of the caisson itself, the first section of the caisson is steadily lowered under controlled conditions. Preferably, a cutting edge can be installed at the bottom of the first section of the caisson to increase the pressure of the caisson on the soil, making it sink more smoothly. During the sinking process, soil can be excavated and removed from the caisson simultaneously through manual excavation, ground machinery excavation, etc. After the first section of the caisson has sunk to the correct position, the second section of the caisson can be installed. The assist unit is disconnected from the first section of the caisson and connected to the second section of the caisson, and the same sinking and soil removal operations are performed. After the second section of the well shaft is lowered into place, the same or similar operations as the second section can be repeated for each subsequent new well shaft. Once a predetermined number of well shafts have been lowered, starting with, for example, the second or third section, an excavating robot, as described above, is installed within the well shaft structure. For example, it is installed on a pre-installed crossbeam within the first section of the well shaft, and in subsequent steps, the excavating robot performs excavation and soil removal operations as described above. In some embodiments, the installation of the excavating robot can be carried out below the waterline after the caisson reaches the groundwater level. Using the excavating robot, caisson construction can be carried out without dewatering. Here, "without dewatering" refers to the active dewatering required in traditional caisson construction. In conventional methods, when the groundwater content in the stratum where the caisson is located is high, pumps or other devices are needed to actively discharge the groundwater within and around the caisson to the surface or other predetermined locations to lower the groundwater level. However, according to the present invention, caisson construction can be carried out without actively dewatering to lower the groundwater level in the stratum surrounding the caisson. Once the caisson structure reaches the designed depth, the bottom section of the caisson is sealed. At this point, only the water inside the caisson structure needs to be drained; this will not affect the groundwater level in the surrounding strata.

[0044] In the above-described caisson construction method, for each section of the caisson, segments can be prefabricated in a factory and assembled into a caisson on site, or the caisson can be constructed on site by casting. During the sinking of each section of the caisson, grouting can be performed to form a friction-reducing grout film between the outer wall of the caisson structure and the soil. Preferably, the hydraulic cylinder of the assist unit can be connected to the caisson via a detachable bearing seat. In the above construction method, after a section of the caisson has sunk to its position, the bearing seat can be placed against a support seat located on the ground, and the bearing seat can be removed from the hydraulic cylinder. The support seat can provide support for the entire sunken caisson structure through the removed bearing seat, preventing the caisson structure from sinking uncontrollably due to gravity after the force applied by the assist unit is removed. Then, the hydraulic cylinder can be raised and connected to a new bearing seat, and then connected to the new section of the caisson.

[0045] It is understandable that in the above-mentioned caisson construction method, steps that do not have a strict operating sequence can be performed simultaneously or in any order according to the actual situation of the construction site.

[0046] The above description of various embodiments of the present invention is provided for illustrative purposes to a person skilled in the art. It is not intended to limit the invention to a single disclosed embodiment. As described above, those skilled in the art will understand that various alternatives and variations of the invention are possible. Therefore, although some alternative embodiments have been specifically described, those skilled in the art will understand or relatively easily develop other embodiments. The present invention is intended to include all alternatives, modifications, and variations of the invention described herein, as well as other embodiments falling within the spirit and scope of the invention described above.

Claims

1. An excavation robot for caisson construction, characterized in that, The well shaft structure is equipped with a fixed position, and the excavation robot includes: A base (21) is installed at the fixed position within the well shaft structure; A support assembly (22) is mounted to the base (21) and configured to rotate relative to the base (21) about a first vertical axis (AX1); A movable arm (23) is mounted to the support assembly (22) and configured to rotate relative to the support assembly (22) about a second vertical axis (AX2), wherein the second vertical axis (AX2) is parallel to the first vertical axis (AX1) and spaced laterally by a predetermined distance. The movable arm (23) is also configured to swing relative to the support assembly (22) about a first transverse axis (AX3). The end of the movable arm (23) is provided with a digging part (231), which is configured to dig the soil in the well structure within a predetermined contour in response to the digging robot running a predetermined program.

2. The excavating robot according to claim 1, characterized in that, The angle of the first transverse axis (AX3) relative to the plane passing through both the first vertical axis (AX1) and the second vertical axis (AX2) changes as the movable arm (23) rotates about the second vertical axis (AX2).

3. The excavating robot according to claim 1, characterized in that, The support assembly (22) is also configured to drive the movable arm (23) to move relative to the base (21) along the first vertical axis (AX1).

4. The excavating robot according to claim 1, characterized in that, The movable arm (23) is provided with a telescopic structure, so that the length of the movable arm (23) is variable.

5. The excavating robot according to claim 4, characterized in that, The telescopic structure is a telescopic structure with at least two stages.

6. The excavating robot according to claim 1, characterized in that, The excavation unit (231) is constructed as a cutter pump, which is connected to the end of the movable arm (23) via a hinge structure.

7. The excavating robot according to any one of claims 1 to 6, characterized in that, The excavating robot is configured to use polar coordinate variable control to adjust the position of the excavating part (231) so that the excavating part (231) can traverse the area within the predetermined contour, wherein the polar coordinates are defined as follows: the projection of the first vertical axis (AX1) in a plane perpendicular to the first vertical axis (AX1) is the pole, and the ray drawn from the projection in a plane perpendicular to the first vertical axis (AX1) is the polar axis, wherein at each corner position of the support assembly (22), the swing plane of the movable arm (23) is parallel to or perpendicular to the polar axis.

8. The excavating robot according to claim 7, characterized in that, The well structure is provided with a cross beam connected to the side wall of the well structure. The first vertical axis (AX1) passes through the center of the cross beam, and one of the beams defines the polar axis.

9. The excavating robot according to claim 8, characterized in that, The predetermined contour is divided into four quadrants by the cross beam, wherein the movement trajectory of the excavator (231) in two adjacent quadrants is symmetrical with respect to the beam separating the two quadrants.

10. A caisson construction system, characterized in that, The caisson construction system includes: A booster unit (10) comprising a plurality of hydraulic cylinders arranged around the well shaft structure (100) of the caisson, the hydraulic cylinders being directly or indirectly connected to a ground base for providing downward pressure and / or lifting force to the well shaft structure (100); and The excavating robot (20) according to any one of claims 1 to 9.

11. A method for constructing a caisson, characterized in that, The caisson construction method includes: Step A: Set up an assist unit, which includes multiple hydraulic cylinders that surround the designed position of the caisson and are connected to the ground base; Step B: Set up the first section of the well shaft, connect the assist unit to the first section of the well shaft, lower the first section of the well shaft to the predetermined position, and simultaneously perform soil removal operation; Step C: Set up a new section of the well shaft, connect the new section of the well shaft to the uppermost well shaft that has been sunk to the position, disconnect the assist unit from the uppermost well shaft that has been sunk to the position and connect it to the new section of the well shaft, sink the new section of the well shaft to the predetermined position, and simultaneously perform soil removal operation; Step E, repeat step C, until the caisson reaches the designed depth; In step E, after a predetermined number of wells have been lowered into place in steps C and D, an excavation robot according to any one of claims 1 to 9 is installed, and the excavation robot is used to perform the soil removal operation in subsequent steps. Step F: Perform a bottom sealing operation on the first section of the wellbore.

12. The caisson construction method according to claim 11, characterized in that, The hydraulic cylinder has a pressure-bearing seat detachably mounted at the end of its extension rod. The hydraulic cylinder is connected to the well shaft via the pressure-bearing seat. In step C, the step of disconnecting the assist unit from the uppermost well shaft that has been lowered into place and connecting it to the new well shaft section further includes: Step C1: Use a support base to vertically support the pressure-bearing seat connected to the uppermost shaft that has already been lowered into place. Step C2: Remove the pressure-bearing seat, which is connected to the uppermost shaft that has been lowered into place, from the hydraulic cylinder. Step C3: Raise the extension rod of the hydraulic cylinder to a high position, install the new pressure bearing seat, and connect the new pressure bearing seat to the new section of the well barrel.

13. The caisson construction method according to claim 12, characterized in that, The pressure-bearing seat is rotatably mounted on the end of the protruding rod via a hinged structure about a second transverse axis.

14. The caisson construction method according to claim 11, characterized in that, The caisson construction method is implemented without actively lowering the groundwater level of the stratum where the caisson is located.

15. The caisson construction method according to claim 14, characterized in that, The excavating robot is equipped with a centering structure. In step E, the excavating robot is installed in place below the water surface.

16. The caisson construction method according to claim 11, characterized in that, The outer surface of the first section of the well casing is provided with a grouting port, and the first section of the well casing and each subsequent section of the well casing include interconnected grouting pipelines. Steps B and C further include: During the sinking of the well, grout is injected between the well and the soil through the grouting pipeline and the grouting port.

17. The caisson construction method according to claim 11, characterized in that, Step B also includes installing a cutting edge at the lower end of the first section of the wellbore.

18. The caisson construction method according to claim 11, characterized in that, The cross-section of the well shaft is circular, elliptical, rectangular, or trapezoidal.

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