Method and structure for correcting deviation of open caisson in stratum with uneven hardness

Abstract

The method comprises the steps that soil layer bearing capacity parameters of a foundation around the open caisson are obtained according to geological survey around the open caisson, and the side, with the worst soil layer bearing capacity, of the foundation around the open caisson is judged so as to obtain the foundation on the weakest side of the open caisson and the foundation on the strong side located on the side opposite to the foundation on the weakest side; a plurality of water injection holes are formed in the strong-side foundation at equal intervals, the distance between each water injection hole and the outer wall of the open caisson is equal, and a plurality of outer bridging plates are arranged on the outer wall of the open caisson close to one side of the weakest-side foundation at equal intervals; water is injected into the water injection holes to enhance the soil layer water content of the strong side foundation, so that the open caisson descends; and after the open caisson descends to the in-position elevation position, constraint double grout is injected into the water injection hole to be used for solidifying the soil layer of the strong side foundation. According to the embodiment of the invention, the outward bridging plate is arranged on the weakest-side foundation with the worst bearing capacity of the foundation soil layer around the open caisson, the water injection hole is formed in the strong-side foundation, the water injection hole injects water to control the descending speed and amplitude of the open caisson, and finally, the soil layer is solidified and stabilized by restraining double grout.

Description

Technical Field

[0001] The invention relates to the technical field of caisson deviation correction, and in particular to a method and structure for correcting the deviation of a caisson in a soft or hard uneven formation. Background Art

[0002] Caisson is a common foundation construction method, widely used in the foundation construction of bridges, docks, buildings and other projects. The caisson sinks to a predetermined depth by its own weight to form a stable foundation platform. Since the caisson needs to pass through different soil layers during the sinking process, especially the soft and hard geological layers with uneven hardness, the caisson is easily affected by various factors such as the difference in the surrounding soil layers, groundwater flow, and additional loads, which may cause the caisson position to deviate. Caisson deviation will not only affect the construction progress, but may also increase the difficulty of subsequent construction and affect the foundation bearing capacity and stability of the structure. Therefore, it is particularly important to control and correct the caisson's position during the sinking process.

[0003] In the current caisson construction, commonly used correction methods include excavation correction, additional load correction and jacking correction. These technical methods adjust the deflection angle or position of the caisson through different means to ensure that the caisson can sink smoothly according to the design requirements. Excavation correction usually adjusts the sinking direction of the caisson by removing the soil layer around the caisson; additional load correction adjusts the movement of the caisson by adding additional loads in the deflection direction of the caisson; jacking correction applies force to the caisson through the action of the jack to correct the deflection. These methods have been widely used in actual projects and have effectively alleviated the problem of caisson deflection.

[0004] However, the existing caisson deviation correction methods have certain technical problems during the construction process. First, the implementation process of these methods is difficult to accurately control, and is often affected by factors such as the actual conditions of the construction site, changes in the soil layer, and the performance of the equipment. It is easy to have excessive or insufficient correction, resulting in secondary deviation of the caisson. Secondly, in soft and hard uneven strata, the caisson is greatly affected by the differences in the bearing capacity of different soil layers, and uneven settlement often occurs, which further aggravates the deflection of the caisson. Although the existing technology can correct the deviation to a certain extent, it is difficult to accurately control it at each construction stage due to factors such as complex operation, long cycle, and high cost. Especially under special geological conditions, there are still great technical difficulties. Therefore, there is an urgent need for an innovative deviation correction method that can not only ensure the correct sinking of the caisson, but also has construction economy and convenience, so as to solve the defects of the current conventional methods. Summary of the invention

[0005] The invention provides a method and structure for rectifying a caisson in a soft and hard uneven stratum, so as to solve the technical problem that the rectification process of a caisson in a soft and hard uneven stratum is difficult to control, resulting in a long and uneconomical caisson rectification construction period.

[0006] In order to solve the above technical problems, the present invention provides a method for correcting the deviation of a caisson in a soft and hard uneven stratum, comprising:

[0007] Obtain bearing capacity parameters of the foundation soil layer around the caisson according to geological surveys around the caisson, determine the side with the worst bearing capacity of the foundation soil layer around the caisson, and obtain the weakest side foundation of the caisson and the strong side foundation located on the opposite side of the weakest side foundation;

[0008] A plurality of water injection holes are arranged at equal intervals on the strong side foundation, and the distance between each water injection hole and the outer wall of the caisson is equal, and a plurality of cantilever plates are arranged at equal intervals on the outer wall of the caisson close to the weakest side foundation;

[0009] Injecting water into the water injection hole to increase the moisture content of the soil layer of the strong side foundation so as to lower the caisson;

[0010] After the caisson is lowered to the emplacement elevation, the constrained double slurry is injected into the water injection hole to solidify the soil layer of the strong side foundation.

[0011] Furthermore, the water injection hole is vertically arranged, the distance from the water injection hole to the outer wall of the caisson is 1000-1500mm, the aperture of the water injection hole is 200-300mm, and the distance between two adjacent water injection holes is 1000-2000mm.

[0012] Furthermore, the height of the caisson is h, and the depth of the water injection hole is H, then the depth range of the water injection hole is: H≥h+1500mm.

[0013] Furthermore, a PVC wall protection pipe for supporting the wall of the water injection hole is arranged in the water injection hole, the PVC wall protection pipe is adapted to the water injection hole, and a plurality of feeding ports penetrating to the inner wall of the water injection hole are opened on the wall of the PVC arm protection pipe.

[0014] Furthermore, the length of the overhanging plate is 1.2-1.5 times the distance from the water injection hole to the outer wall of the caisson, and the distance between the two outermost water injection holes is smaller than the distance between the outer walls of the two outermost overhanging plates.

[0015] Furthermore, the cantilever plate is integrally formed and cast during the construction of the caisson.

[0016] Furthermore, the injection medium of the water injection hole is replaced according to the moisture content of the soil layer. When the moisture content of the soil layer of the strong side foundation reaches 90%-95% of the liquid and plastic limit moisture content, the water injection hole stops injecting water; when the moisture content of the soil layer of the strong side foundation drops to 70%-80% of the liquid and plastic limit moisture content, the constrained double liquid slurry is injected into the water injection hole instead.

[0017] Furthermore, the constrained dual-liquid slurry includes water glass and cement slurry, and the water-cement ratio of the water glass and the cement slurry is 0.5-0.65.

[0018] Furthermore, the water injection amount of the water injection hole is adjusted according to the verticality change of the caisson, and when the verticality change exceeds 5 degrees, the water injection pressure of the water injection hole is reduced to 50-60% of the initial water injection pressure.

[0019] On the other hand, the present invention also provides a caisson correction structure for soft and hard uneven strata, which is made by any of the methods described above.

[0020] Compared with the prior art, the method and structure for correcting the deviation of a caisson in a soft and hard uneven stratum according to the embodiment of the present invention have the following beneficial effects:

[0021] The embodiment of the present invention obtains the bearing capacity parameters of the foundation soil layer around the caisson by surveying the geological conditions of the foundation soil layer around the caisson, and determines the weakest side foundation with the worst bearing capacity of the foundation soil layer around the caisson through comparison. Based on the identified weakest side foundation, a water injection hole is opened on the strong side foundation on the side relative to the weakest side foundation, and the water content of the soil layer of the strong side foundation is enhanced by controlling the water injection into the water injection hole, thereby softening the strong side foundation soil layer and reducing the friction of the soil layer. Combined with the resistance-increasing effect of the overhanging plate set on the weakest side foundation on the caisson, not only can the caisson that is inclined to the weakest side foundation gradually return to the right position, thereby avoiding the caisson from being greatly deflected or even overturned, and ensuring the safety of subsequent construction, but also the settlement speed and amplitude of the caisson can be effectively controlled by adjusting the water injection, so that the caisson always maintains the right position and settles evenly during the sinking process, avoiding excessive or uneven local settlement, and reducing the construction difficulty and maintenance cost. This significantly improves the controllability of caisson construction and simplifies the subsequent maintenance work. At the same time, in order to avoid the problem of reverse tilt of the strong side foundation of the caisson, when the caisson reaches the designed positioning elevation, the method of injecting constrained double slurry into the injection holes is changed, which can effectively solidify the softened strong side foundation soil layer, which can not only enhance the compressive strength of the strong side foundation and increase the stability of the soil layer, but also reduce the looseness and softening of the strong side foundation soil layer, thereby enhancing the caisson's anti-tilting ability and ensuring the long-term stability of the caisson structure.

[0022] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to better understand the present invention and do not constitute a limitation of the present invention.

[0024] Figure 1It is a structural schematic diagram of a caisson deviation correction structure for soft and hard uneven strata provided by an embodiment of the present invention;

[0025] Figure 2 It is a cross-sectional schematic diagram of a caisson correction structure for soft and hard uneven formations provided by an embodiment of the present invention.

[0026] In the figure, 1. caisson; 2. water injection hole; 3. cantilever plate; 4. PVC wall protection pipe; 5. tough foot. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings and embodiments in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that directional words, such as the terms "middle", "upper", "lower", "inside" and "outside", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present invention.

[0029] In the present invention, unless otherwise specified and limited, the terms "assemble", "connect", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] like Figure 1-2 As shown, an embodiment of the present invention provides a method for correcting the deviation of a caisson in a soft and hard uneven formation, comprising:

[0031] According to the geological survey around the caisson 1, the bearing capacity parameters of the foundation soil layer around the caisson 1 are obtained, and the side with the worst bearing capacity of the foundation soil layer around the caisson 1 is determined to obtain the weakest side foundation of the caisson 1 and the strong side foundation located on the opposite side of the weakest side foundation;

[0032] A plurality of water injection holes 2 are arranged at equal intervals on the strong side foundation, and the distance between each water injection hole 2 and the outer wall of the caisson 1 is equal, and a plurality of cantilever plates 3 are arranged at equal intervals on the outer wall of the caisson 1 on the side close to the weakest side foundation;

[0033] Inject water into the water injection hole 2 to increase the moisture content of the soil layer of the strong side foundation, so as to lower the caisson 1;

[0034] After the caisson 1 is lowered to the emplacement elevation, the constrained double slurry is injected into the water injection hole 2 to solidify the soil layer of the strong side foundation.

[0035] The embodiment of the present invention obtains the bearing capacity parameters of the foundation soil layer around the caisson 1 by surveying the geological conditions of the foundation soil layer around the caisson 1, and determines the weakest side foundation with the worst bearing capacity of the foundation soil layer around the caisson 1 through comparison, and opens a water injection hole 2 on the strong side foundation on the side relative to the weakest side foundation based on the identified weakest side foundation, and controls the water injection into the water injection hole 2 to enhance the moisture content of the soil layer of the strong side foundation, thereby softening the strong side foundation soil layer and reducing the friction of the soil layer, and combined with the resistance-increasing effect of the overhanging plate 3 set on the weakest side foundation on the caisson 1, not only can the caisson 1 that is inclined to the weakest side foundation be gradually straightened, thereby avoiding the caisson 1 from being significantly deflected or even overturned, and ensuring the safety of subsequent construction, but also the settlement speed and amplitude of the caisson 1 can be effectively controlled by adjusting the water injection, so that the caisson 1 always maintains the correct position and settles evenly during the sinking process, avoiding excessive or uneven local settlement, and reducing the construction difficulty and maintenance cost. This significantly improved the controllability of the construction of caisson 1 and simplified the subsequent maintenance work. At the same time, in order to avoid the problem of reverse tilting of the strong side foundation of caisson 1, when caisson 1 reaches the designed elevation position, the method of injecting constrained double slurry into the water injection hole 2 can effectively solidify the softened strong side foundation soil layer, which can not only enhance the compressive strength of the strong side foundation and increase the stability of the soil layer, but also reduce the looseness and softening of the strong side foundation soil layer, thereby enhancing the anti-tilting ability of caisson 1 and ensuring the long-term stability of the caisson 1 structure.

[0036] Among them, the acquisition and processing of geological survey data around Caisson 1 is a key step to ensure the safety and quality of Caisson 1 construction. First, it is necessary to set up exploration points around Caisson 1 to collect the foundation soil parameters of each point, including soil type, soil thickness, deep burial data, cohesion, internal friction angle and other physical and mechanical indicators. For example, for each side of the soil layer of Caisson 1, the soil layer thickness change rate and burial depth difference between adjacent exploration points are calculated to quantify the uniformity of soil layer distribution. For example, if the thickness change rate of a soil layer between two adjacent exploration points exceeds the preset threshold (such as 10%), it indicates that the soil layer distribution in this area is uneven and needs special attention. For example, in a certain Caisson 1 project, the exploration found that the surface layer is silty clay with a thickness of about 2 meters, cohesion of 15kPa, and friction angle of 18 degrees; the lower layer is medium-dense sand with a thickness of 4 meters and a relative density of 0.65. When calculating the characteristic value of foundation bearing capacity using the finite element analysis method, soil layer parameters and superstructure loads need to be considered. Assuming that the total weight of the upper structure of caisson 1 is 5000kN, the foundation bearing capacity of each exploration point can be obtained through finite element software modeling and analysis. The calculation results show that the foundation bearing capacity around caisson 1 varies between 280kPa and 350kPa. Statistical analysis of foundation bearing capacity parameters is crucial to assessing the risk of uneven settlement. If the difference between the maximum and minimum values ​​exceeds 10% of the maximum bearing capacity, it is determined that there is a risk of uneven settlement. In the above example, the bearing capacity difference is 70kPa, accounting for 20% of the maximum value, which exceeds the threshold, indicating that the foundation bearing capacity around caisson 1 is unevenly distributed.

[0037] According to the geological survey report around Caisson 1, the foundation soil layer parameters of each exploration point are extracted, and the geological parameter database around Caisson 1 can be established using Microsoft Access. The static analysis module of the finite element software ANSYS is used to calculate the bearing capacity characteristic value of the foundation at each exploration point, combined with the soil layer parameters and the superstructure construction load and permanent load, and the foundation bearing capacity parameters of multiple locations around Caisson 1 are obtained. Using the spatial analysis module of ArcGIS, the foundation bearing capacity parameters of each point around Caisson 1 are analyzed by Kriging interpolation, and the area with the smallest foundation soil layer bearing capacity parameters around Caisson 1 can be further extracted, and the side with the worst foundation bearing capacity around Caisson 1 can be determined, which is identified as the weakest side foundation of Caisson 1, and the side relative to the weakest side foundation is the strong side foundation.

[0038] It should be noted that in the soft and hard uneven strata around caisson 1, the definition of "strong side foundation" is particularly emphasized: the strong side foundation does not absolutely mean that the bearing capacity of the foundation soil layer of the side foundation is the strongest, but relative to the weakest side foundation, its foundation soil layer bearing capacity belongs to the higher side. This means that the bearing capacity of the foundation soil layer of the strong side foundation may be between the strongest side and the other foundation sides, or it may also be the strongest side, but in essence it is a reference side in contrast to the weakest side foundation, that is, the weakest side foundation and the strong side foundation are relatively located on both sides of caisson 1. Constrained double grout is a specific engineering material used to reinforce foundations or geotechnical structures. It realizes the constraint and support of the structure by solidifying or enhancing the stability of the foundation soil layer. Its components are usually mixed by two substances to produce a specific chemical reaction, thereby achieving the effect of solidification and reinforcement, such as cement-water glass slurry, cement-bentonite slurry, polymer-modified slurry and ultrafine cement slurry.

[0039] In an optional embodiment of the present invention, the water injection hole 2 is vertically arranged, the distance from the water injection hole 2 to the outer wall of the caisson 1 is 1000-1500mm, the aperture of the water injection hole 2 is 200-300mm, and the distance between two adjacent water injection holes 2 is 1000-2000mm.

[0040] Specifically, by setting the water injection hole 2 vertically, the uniformity and accuracy of the water injection process can be ensured. The vertically arranged water injection hole 2 can effectively control the direction of the water flow, ensure that the water penetrates evenly into the foundation soil layer, avoid local excessive water injection or uneven water injection, and thus achieve optimized reinforcement of the strong side foundation. The distance from the water injection hole 2 to the outer wall of the caisson 1 is 1000-1500mm, which helps to control the depth of the water injection hole 2 and the relative position of the outer wall. This distance range ensures that the water injection can be evenly distributed to the soil layer around the caisson 1, avoiding excessive water injection affecting the settlement process of the caisson 1, while improving the water injection effect, so that the strong side foundation soil layer is effectively softened and improved. The aperture of the water injection hole 2 is 200-300mm. This aperture range can effectively increase the water injection flow rate, while avoiding soil layer damage or instability that may be caused by excessive aperture. Through reasonable aperture setting, rapid and effective water injection can be achieved, avoiding excessive interference to the surrounding environment, and improving construction efficiency. The spacing between two adjacent water injection holes 2 is 1000-2000mm. This spacing setting can ensure uniform distribution of water injection, avoid the distance between the water injection holes 2 being too small to cause local excessive water addition or too large to cause uneven water diffusion. Reasonable spacing helps to uniformly reinforce the foundation soil layer on the strong side, ensure the stability of the caisson 1 during the settlement process, thereby achieving uniform settlement, avoiding excessive or uneven local settlement, and reducing later construction difficulties and maintenance costs.

[0041] Among them, the arrangement of water injection hole 2 can be evaluated by finite element analysis to assess its impact on the structure and foundation of caisson 1. In the model, water injection hole 2 can be set as a cylindrical hole, and local mesh encryption can be performed around it. When setting boundary conditions, the water pressure changes during the water injection process can be considered to analyze the impact of different water injection stages on the stability of caisson 1. Through stress distribution cloud map and deformation analysis, the impact of the arrangement of water injection hole 2 on the overall performance of caisson 1 can be intuitively evaluated, providing a basis for the optimal design of the arrangement of water injection hole 2.

[0042] It should be noted that, through the appropriate setting of the water injection holes 2, the progress of water injection and the softening process of the strong side foundation can be accurately regulated, thereby effectively reducing the friction of the strong side foundation soil layer, providing a strong guarantee for the uniform settlement of the caisson 1, and avoiding the tilting or deformation of the caisson 1 during the settlement process.

[0043] like Figure 2 As shown, in an optional embodiment of the present invention, the height of the caisson 1 is h, the depth of the water injection hole 2 is H, and the depth range of the water injection hole 2 is: H≥h+1500mm.

[0044] Specifically, by setting the depth H of the water injection hole 2 to be greater than the height h of the caisson 1 and increasing the depth by 1500mm, it can be ensured that the water injection hole 2 penetrates into the key part of the strong side foundation soil layer. This depth setting helps to fully penetrate water into the deep layer of the foundation. Water injection not only works on the surface layer, but also has a softening effect on the deep soil layer, softening the foundation soil layer to the greatest extent, which can better adjust and optimize the soil quality of the entire strong side foundation, avoid the problem of local excessive softening caused by water injection only in the shallow area, improve the stability and bearing capacity of the strong side foundation, and ensure that the caisson 1 can settle smoothly and evenly. It should be noted that a flexible foot 5 can be provided at the bottom of the caisson 1. In the design, if a flexible foot 5 is provided at the bottom of the caisson 1, in order to ensure that the water injection effect covers the entire caisson 1 and the surrounding foundation soil layer, the depth H of the water injection hole 2 should be set to be more than 1500mm beyond the bottom of the flexible foot 5. This helps to ensure the reinforcement effect of the water injection on the soil layer around the caisson 1, improve the stability and controllability of the caisson 1 during the construction process, and avoid interference with the structure of the flexible foot 5, ensuring its reinforcement effect.

[0045] The method of calculating the minimum water injection depth according to the height h of caisson 1 ensures sufficient water pressure, which is conducive to the stability and sinking effect of caisson 1. For example, if the height of caisson 1 is 15 meters, the minimum water injection depth H should be 16.5 meters. This depth requirement not only takes into account the height of caisson 1 itself, but also reserves a safety margin of 1.5 meters to cope with possible geological changes and water level fluctuations. The real-time monitoring of water injection depth can adopt the CYT-153 type immersion level transmitter, with a measurement range of 0-20m, an accuracy of ±5% FS, and an output of 4-20mA standard current signal. This sensor has high accuracy and reliability. Fix it on the inner wall of the water injection hole 2, about 0.5 meters from the bottom of the hole, so as to avoid the sediment from affecting the measurement accuracy, while ensuring that the sensor is always immersed in water.

[0046] like Figure 2 As shown, in an optional embodiment of the present invention, a PVC wall protection tube 4 for supporting the wall of the water injection hole 2 is arranged in the water injection hole 2, the PVC wall protection tube 4 is adapted to the water injection hole 2, and a plurality of feed ports penetrating to the inner wall of the water injection hole 2 are opened on the wall of the PVC arm protection tube.

[0047] Specifically, the setting of the PVC wall protection pipe 4 effectively supports the hole wall of the water injection hole 2, preventing the water injection hole 2 from collapsing, deforming or shrinking due to soft soil or external force during the construction process. Especially under soft soil or loose geological conditions, the wall protection pipe can protect the integrity of the water injection hole 2, ensure the smooth progress of the water injection process, and thus improve the safety and controllability of the construction. A plurality of feed ports that penetrate to the inner wall of the water injection hole 2 are provided on the wall of the PVC wall protection pipe 4, effectively avoiding the problem of hole wall blockage that may occur during the water injection process. These feed ports ensure that the injection liquid can flow freely, reduce the blockage caused by particulate matter or other impurities in the soil entering the water injection hole 2, and maintain the smoothness and efficiency of the water injection hole 2.

[0048] The stronger bearing capacity of the soil layer of the strong side foundation is only relative to the weakest side foundation on the other side. The soil layer on the strong side foundation may also be soft and easy to collapse. Therefore, a PVC wall protection pipe 4 with multiple feeding ports is set in the water injection hole 2 to ensure the stability of the wall of the water injection hole 2 during the water injection process, avoid soil layer collapse or blockage, and improve the uniformity and effectiveness of water injection.

[0049] It should be noted that the PVC wall protection tube 4 is a lightweight and high-strength material that is easy to install and has a short construction period. After the wall protection tube is set, the construction process of the water injection hole 2 will be smoother, and the construction personnel can complete the construction task of the water injection hole 2 more quickly. At the same time, the PVC material has the advantages of corrosion resistance and aging resistance, and can maintain good performance in long-term use, reducing maintenance and replacement costs. The use of the PVC wall protection tube 4 solves the problem of easy collapse of the traditional water injection hole 2 and extends the service life of the water injection hole 2.

[0050] In an optional embodiment of the present invention, the length of the cantilever plate 3 is 1.2-1.5 times the distance from the water injection hole 2 to the outer wall of the caisson 1, and the distance between the two outermost water injection holes 2 is smaller than the distance between the outer walls of the two outermost cantilever plates 3.

[0051] Specifically, the design of the overhang plate 3 can effectively adjust and balance the foundation pressure on both sides of the caisson 1. Since the overhang plate 3 extends to the far side of the water injection hole 2, it can balance the pressure difference between the weakest side foundation and the strong side foundation during the settlement of the caisson 1 by changing the mechanical action point on the outside of the caisson 1, thereby reducing the unstable settlement caused by uneven pressure. This helps to avoid the caisson 1 from tilting or excessive local settlement during the construction process, thereby improving the stability of the caisson 1. The distance between the two outermost water injection holes 2 is smaller than the distance between the outer walls of the two outermost overhang plates 3, which can ensure that the supporting effect of the overhang plate 3 is more effective. The position of the water injection hole 2 and the layout of the overhang plate 3 cooperate with each other to achieve the best mechanical distribution, so that the softening effect on the foundation during the water injection process is more uniform, avoiding the phenomenon of excessive or uneven local settlement. Such a spatial layout improves the stability and controllability of the entire caisson 1 structure.

[0052] Among them, the length of the overhanging plate 3 is 1.2-1.5 times the distance from the water injection hole 2 to the outer wall of the caisson 1. This design can enhance the supporting effect of the overhanging plate 3 during the water injection process, and can ensure that the supporting effect of the overhanging plate 3 is coordinated with the water injection process of the water injection hole 2. This coordination allows the injection liquid to act evenly on the foundation soil layer. At the same time, the supporting force provided by the overhanging plate 3 can effectively prevent the caisson 1 from producing uneven settlement during the water injection process, and ensure the balance and stability of the settlement process of the caisson 1. When the water injection hole 2 is filled with water, the overhanging plate 3 can prevent the soil layer on one side of the caisson 1 from being excessively affected by supporting the outer wall of the caisson 1, and ensure that the settlement process of the caisson 1 is more uniform and stable. In addition, the design of the overhanging plate 3 helps to achieve precise control during the settlement process, avoiding the caisson 1 from settling too fast or too large, thereby improving the safety and controllability of the construction.

[0053] In an optional embodiment of the present invention, the cantilever plate 3 is integrally formed and cast during the construction of the caisson 1 .

[0054] Specifically, by integrally forming the cantilever plate 3 and the caisson 1, it is ensured that there is no connection gap or contact point between the caisson 1 and the cantilever plate 3, thereby enhancing the integrity of the structure. Such a design can avoid potential structural weaknesses caused by the joint problem between the cantilever plate 3 and the caisson 1, reduce problems such as loose connection or falling off that may occur during the construction process, and improve the bearing capacity and deformation resistance of the caisson 1 and the cantilever plate 3. Usually, the construction of the caisson 1 needs to be carried out deep underground. The cantilever plate 3 is integrally formed and cast during the construction process of the caisson 1, which can reduce the complexity of multiple construction links and avoid the steps of connecting the cantilever plate 3 and the caisson 1 after they are constructed separately. In this way, the construction process is smoother, the construction period is shortened, and the construction efficiency is improved. This integrated design not only has significant advantages in the construction stage, but also can improve the economy and safety of the project, which is of great significance to the smooth implementation of the entire project.

[0055] In an optional embodiment of the present invention, the injection medium of the water injection hole 2 is replaced according to the moisture content of the soil layer. When the moisture content of the soil layer of the strong side foundation reaches 90%-95% of the liquid and plastic limit moisture content, the water injection hole 2 stops injecting water; when the moisture content of the soil layer of the strong side foundation drops to 70%-80% of the liquid and plastic limit moisture content, the constrained double liquid slurry is injected into the water injection hole 2 instead.

[0056] Specifically, the liquid-plastic limit moisture content of the strong side foundation soil layer is measured by a liquid-plastic limit combined measuring instrument, and it is used as a reference value for judging the timing of replacing the injection medium of the water injection hole 2. According to the difference between the soil layer moisture content and the liquid-plastic limit moisture content, it is judged whether the injection medium of the water injection hole 2 needs to be replaced. If the difference is within the range of 20%-30% of the liquid-plastic limit moisture content, the current injection medium is maintained unchanged, that is, water injection is maintained; if the soil layer moisture content reaches 80%-85% of the liquid-plastic limit moisture content, the water injection hole 2 is controlled to reduce the water injection amount to avoid excessive water injection and cause the soil layer strength to decrease. When the soil layer moisture content continues to rise to more than 90% of the liquid-plastic limit moisture content, the water injection is stopped. During the water injection process, the moisture content change of the strong side foundation soil layer is continuously monitored. If it is monitored that the soil layer moisture content drops to 70%-80% of the liquid-plastic limit moisture content, the constrained double liquid slurry is injected into the water injection hole 2, and the strength and stability of the soil layer are improved through the coagulation effect of the constrained double liquid slurry. According to the monitoring results, the injection medium of injection hole 2 is dynamically adjusted to ensure that the moisture content of the soil layer is maintained within a reasonable range. By optimizing the layout and injection parameters of injection hole 2, combined with real-time monitoring data feedback, and using the PID control algorithm to establish an automatic control system for the replacement of the injection medium of injection hole 2, the automatic regulation of the water injection process is realized, and the water injection efficiency and accuracy are improved.

[0057] For example, taking a coastal port project as an example, the liquid limit of the strong side foundation soil layer was measured to be 35% and the plastic limit was 20% by the liquid-plastic limit combined measuring instrument. This data provides a key reference value for judging the timing of replacing the injection medium of injection hole 2. The drying method is a common method for determining the natural moisture content of the soil. In this project, the natural moisture content of the strong side foundation soil layer was measured to be 18% after sampling at 105°C for 24 hours. It was calculated that the difference between the soil layer moisture content and the liquid limit was 17%, which is about 48.6% of the liquid limit. This difference indicates that the current soil layer moisture content is low and water injection is required to reduce the foundation strength. Based on the measured data, the engineering team formulated a water injection strategy. When the soil layer moisture content reaches 80% (i.e. 28%) of the liquid limit, the water injection volume begins to be reduced. This measure is intended to avoid excessive water injection leading to a sharp drop in soil layer strength and ensure the safety of caisson 1 construction. At the same time, a threshold for stopping water injection is set, that is, when the soil layer moisture content reaches 90% (31.5%) of the liquid limit. During the water injection process, a portable soil moisture meter was used to monitor the change of soil moisture content in real time. When the moisture content was detected to be 75% (26.25%) of the liquid limit, the engineer decided to inject the constrained dual-liquid slurry into the water injection hole 2.

[0058] It should be noted that, by precisely controlling the water injection hole 2, the risk of foundation softening or uneven solidification caused by excessively high or low soil moisture content can be effectively avoided. In particular, stopping water injection when the soil moisture content is high helps prevent the soil from further softening and losing the necessary bearing capacity; and using constrained double slurry when the soil moisture content is low can enhance the stability of the soil and reduce potential construction risks. Liquid limit moisture content is an indicator commonly used in soil engineering to measure the plasticity and fluidity of soil. Liquid limit moisture content refers to the moisture content of soil between the liquid state and the plastic state, and the plastic state and the solid state. Liquid limit and plastic limit are used to divide the type and plasticity of soil. The liquid limit and plastic limit of soil can be used to determine its engineering properties, which is very important, especially in soil improvement, foundation treatment and other projects.

[0059] In an optional embodiment of the present invention, the constrained dual-liquid slurry includes water glass and cement slurry, and the water-cement ratio of the water glass and the cement slurry is 0.5-0.6.

[0060] Specifically, the combined use of water glass and cement slurry can effectively enhance the solidification effect of the soil layer. Water glass has strong permeability and reactivity, and can penetrate into the soil layer to react chemically with soil particles to form a dense gel structure, thereby improving the water resistance and stability of the soil layer. Cement slurry can provide strong structural support and enhance the compressive resistance and stability of the soil layer. The combination of the two can provide a more durable and uniform solidification effect while ensuring the density of the soil layer. The water-cement ratio of water glass and cement slurry is in the specific range of 0.5-0.6, which can achieve the best solidification and strength development of cement slurry on the basis of ensuring the fluidity and permeability of the slurry. This water-cement ratio can effectively balance the cohesiveness and permeability of the slurry, so that the cement slurry can not only penetrate into the voids of the soil layer, but also interact with water glass to form a solid structure, improving the durability and deformation resistance of the soil layer.

[0061] Among them, the engineering team collected 500 sets of ratio experimental data, covering the full range of water-cement ratio of 0.5-0.6. The engineering team found that the constrained dual-liquid slurry showed the best comprehensive performance when the water-cement ratio was in the range of 0.30-0.40. Specifically, when the water-cement ratio was 0.35, the compressive strength measured over several days reached 2.5MPa, and the setting time was controlled within 4 hours. This ratio achieved a good balance between strength and setting time.

[0062] In an optional embodiment of the present invention, the water injection amount of the water injection hole 2 is adjusted according to the verticality change of the caisson 1. When the verticality change exceeds 5 degrees, the water injection pressure of the water injection hole 2 is reduced to 50-60% of the initial water injection pressure.

[0063] Specifically, the verticality change during the correction process of caisson 1 is usually caused by the uneven settlement of the soil layers on both sides of caisson 1. By adjusting the water injection pressure of the water injection hole 2 according to the change in the verticality of caisson 1, the phenomenon of caisson 1 sinking too quickly during the settlement process can be effectively avoided. When the verticality change of caisson 1 exceeds 5 degrees, reducing the water injection pressure will help slow down the settlement speed of caisson 1 and avoid the caisson 1 settling too quickly on one side due to excessive water injection, further increasing the risk of tilting of caisson 1. By real-time monitoring of the verticality change of caisson 1 and adjusting the water injection pressure according to the change, the safety of caisson 1 construction can be greatly improved. Excessive tilt of caisson 1 may affect the structural stability during the construction process, reduce the quality of the project, and even affect the later use. The measure of adjusting the water injection pressure can effectively control the settlement process of caisson 1, avoid serious risks of tilting or overturning, and ensure the smooth progress of the construction process.

[0064] Among them, the real-time verticality data acquisition system can collect the position information of the top and bottom of the caisson 1 every second through high-precision tilt sensors and laser rangefinders, and calculate the verticality deviation. The preset standard verticality is usually based on engineering design requirements. When the verticality change exceeds the 5-degree threshold, the pressure adjustment step is triggered to reduce the injection pressure of the water injection hole 2 to 50-60% of the initial water injection pressure. At this time, the verticality deviation monitored in real time will be used as an adjustment basis to further adjust the injection pressure of the water injection hole 2 and control the injection volume, so as to balance the settlement process on both sides of the caisson 1, avoid the phenomenon of skewing or excessive tilting of the caisson 1, ensure that the caisson 1 can settle evenly according to the predetermined design position, and improve the safety and controllability during the construction process.

[0065] like Figure 1-2 As shown, an embodiment of the present invention also provides a correction structure for caisson 1 in soft and hard uneven strata, which is made by the above method and can effectively solve the problems of uneven settlement and tilt of caisson 1 caused by soft and hard uneven strata. By dynamically adjusting the injection pressure and injection volume of the water injection hole 2 and using technical means such as constrained double slurry, it can be ensured that the settlement process of caisson 1 is uniform and stable, avoiding potential risks caused by foundation differences, and improving construction accuracy and convenience of later maintenance. This structure is suitable for the construction of caisson 1 under complex geological conditions, and provides an effective solution for the correction of settlement of uneven foundations.

[0066] The method for correcting the deviation of a caisson in a soft and hard uneven formation provided by the embodiment of the present invention can be applied to the working scenario of correcting the deviation of a caisson 1 in a soft and hard uneven formation, and provides users with an efficient, economical and easy-to-control construction method for correcting the deviation of a caisson 1. When using this method to correct the deviation of a caisson 1 in a soft and hard uneven formation, the actual working process of controlling the descent speed and amplitude of the caisson 1 by controlling the injection pressure of the water injection hole 2 is as follows:

[0067] The embodiment of the present invention obtains the bearing capacity parameters of the foundation soil layer around the caisson 1 by surveying the geological conditions of the foundation soil layer around the caisson 1, and determines the weakest side foundation with the worst bearing capacity of the foundation soil layer around the caisson 1 through comparison. Based on the identified weakest side foundation, a water injection hole 2 is opened on the strong side foundation on the side relative to the weakest side foundation. In order to avoid the problem of hole wall collapse and blocking of the water injection hole 2 during the water injection process of the water injection hole 2, a PVC wall protection pipe 4 can be optionally set in the water injection hole 2 to support the hole wall, and then the strong side is enhanced by controlling the water injection into the water injection hole 2. The moisture content of the soil layer of the foundation is used to soften the soil layer on the strong side of the foundation to reduce the friction of the soil layer. Combined with the resistance-increasing effect of the overhanging plate 3 set on the weakest side foundation on the caisson 1, it can not only make the caisson 1 that is inclined to the weakest side foundation gradually return to the right position, thereby avoiding the caisson 1 from being greatly deflected or even overturned, ensuring the safety of subsequent construction, but also effectively control the settlement speed and amplitude of the caisson 1 by adjusting the water injection, so that the caisson 1 always maintains the right position and settles evenly during the sinking process, avoiding excessive or uneven local settlement, and reducing the construction difficulty and maintenance cost. This move significantly improves the controllability of the caisson 1 construction and simplifies the subsequent maintenance work. At the same time, in order to avoid the problem of reverse tilting of the strong side foundation of caisson 1, when caisson 1 reaches the designed installation elevation, the constrained double slurry is injected into the injection hole 2, which can effectively solidify the softened strong side foundation soil layer, which can not only enhance the compressive strength of the strong side foundation and increase the stability of the soil layer, but also reduce the looseness and softening of the strong side foundation soil layer, thereby enhancing the anti-tilting ability of caisson 1 and ensuring the long-term stability of the caisson 1 structure.

[0068] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for correcting the deviation of a caisson in a soft and hard uneven stratum, characterized in that: include: Obtain bearing capacity parameters of the foundation soil layer around the caisson according to geological surveys around the caisson, determine the side with the worst bearing capacity of the foundation soil layer around the caisson, and obtain the weakest side foundation of the caisson and the strong side foundation located on the opposite side of the weakest side foundation; A plurality of water injection holes are arranged at equal intervals on the strong side foundation, and the distance between each water injection hole and the outer wall of the caisson is equal, and a plurality of cantilever plates are arranged at equal intervals on the outer wall of the caisson close to the weakest side foundation; Injecting water into the water injection hole to increase the moisture content of the soil layer of the strong side foundation so as to lower the caisson; After the caisson is lowered to the emplacement elevation, the constrained double slurry is injected into the water injection hole to solidify the soil layer of the strong side foundation.

2. The method for correcting the deviation of a caisson in soft and hard uneven strata according to claim 1 is characterized in that: The water injection holes are vertically arranged, the distance from the water injection holes to the outer wall of the caisson is 1000-1500mm, the aperture of the water injection holes is 200-300mm, and the spacing between two adjacent water injection holes is 1000-2000mm.

3. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 2 is characterized in that: The height of the caisson is h, and the depth of the water injection hole is H, then the depth range of the water injection hole is: H≥h+1500mm.

4. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 2 is characterized in that: A PVC wall protection pipe for supporting the wall of the water injection hole is arranged in the water injection hole, the PVC wall protection pipe is adapted to the water injection hole, and a plurality of feeding ports penetrating to the inner wall of the water injection hole are opened on the wall of the PVC arm protection pipe.

5. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 2 is characterized in that: The length of the overhanging plate is 1.2-1.5 times the distance from the water injection hole to the outer wall of the caisson, and the distance between the two outermost water injection holes is smaller than the distance between the outer walls of the two outermost overhanging plates.

6. The method for correcting the deviation of a caisson in soft and hard uneven strata according to claim 5 is characterized in that: The cantilever plate is integrally formed and cast during the construction of the caisson.

7. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 1 is characterized in that: The injection medium of the water injection hole is replaced according to the moisture content of the soil layer. When the moisture content of the soil layer of the strong side foundation reaches 90%%-95% of the liquid limit moisture content, the water injection hole stops injecting water; When the moisture content of the soil layer of the strong side foundation drops to 70%-80% of the liquid-plastic limit moisture content, the constrained dual-liquid slurry is injected into the water injection hole instead.

8. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 7 is characterized in that: The constrained dual-liquid slurry includes water glass and cement slurry, and the water-cement ratio of the water glass and the cement slurry is 0.5-0.

65.

9. The method for correcting the deviation of a caisson in a soft and hard uneven stratum according to claim 7, characterized in that: The water injection volume of the water injection hole is adjusted according to the verticality change of the caisson. When the verticality change exceeds 5 degrees, the water injection pressure of the water injection hole is reduced to 50-60% of the initial water injection pressure.

10. A caisson deviation correction structure for soft and hard uneven strata, characterized by: The method is prepared by any one of claims 1 to 9.

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