A construction method for pile hole retaining wall for dredging and inhibiting stagnant water seepage

Abstract

The application provides a construction method for pile hole wall protection for water seepage dredging and inhibition, and relates to the technical field of pile foundation construction in building engineering, which comprises the following steps: identifying a water-logged layer in a rotary drilling process; using a large-diameter drilling tool to form a hole at an original pile position, and the pile hole needs to penetrate the water-logged layer; backfilling silty clay to the ground in the pile hole; using a small-diameter drilling tool to re-drill, and forming an annular silty clay wall in the pile hole. The construction method forms a silty clay wall structure with a certain thickness on the side of the pile hole, the silty clay wall can slow down and dredge seepage, the silty clay has a certain adsorption and cementation, which is helpful to the stability of the soil structure, can still maintain a certain strength after water saturation, and is widely available, low in price, green and environmentally friendly, effectively solves the hole collapse problem caused by water seepage, and does not need to additionally invest in mechanical equipment.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction technology in building engineering, and in particular to a construction method for pile hole retaining wall for guiding and inhibiting the seepage of stagnant water. Background Technology

[0002] Perched water is often distributed above soil layers that are not easily permeable, such as clay layers, especially in low-lying areas such as riverbeds and gullies that have been artificially filled. Currently, in such disorderly filled foundations, the problem of large-scale collapse caused by the seepage of perched water is very prominent.

[0003] In the existing technology, the first method for dealing with collapsed holes is to directly pour concrete into the pile hole, wait for it to solidify, and then re-drill; the second method is to backfill with water-stopping gel material and then re-drill.

[0004] In the process of realizing this invention, the inventors found that the prior art has at least the following problems: Although the first treatment method can stabilize the hole wall to a certain extent, it has problems such as long construction period, high labor cost and large amount of concrete consumption; The second treatment method has a good water-stopping effect, but due to the high strength of the gel material, it is difficult to effectively separate or degrade after pile formation, resulting in material waste and increased construction costs. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, the purpose of this invention is to propose a construction method for pile hole wall protection for guiding and inhibiting stagnant water seepage, which solves the problem of hole collapse caused by stagnant water seepage at a lower cost, and overcomes the problems of excessive strength of wall protection materials, difficulty in removal, and waste caused by existing technologies.

[0007] To achieve the above objectives, this invention proposes a construction method for retaining the wall of pile holes for guiding and inhibiting the seepage of stagnant water, comprising:

[0008] The rotary drilling process identified a water-permeable layer.

[0009] Large-diameter drilling tools were used to drill holes at the original pile location, and the depth of the pile hole needed to penetrate the perched water layer.

[0010] Backfill the pile hole with silty clay to the ground surface;

[0011] Small-diameter drill bits were used for re-drilling, forming a ring-shaped silty clay wall inside the pile hole.

[0012] The beneficial effects of the construction method for pile hole retaining wall for guiding and suppressing stagnant water seepage according to the present invention are as follows: by adopting the process of "large-diameter hole enlargement + silty clay backfilling + small-diameter re-drilling" after identifying the stagnant water layer, a silty clay retaining wall structure with a certain thickness is formed around the pile hole. The silty clay retaining wall can slow down and guide seepage. Silty clay has a certain adsorption and cementing properties, which helps stabilize the soil structure. It can still maintain a certain strength after absorbing water saturation. Moreover, the material is widely available, inexpensive, green and environmentally friendly, effectively solving the problem of hole collapse caused by stagnant water seepage, without the need for additional investment in mechanical equipment.

[0013] According to one embodiment of the present invention, before drilling a hole at the original pile location using a large-diameter drilling tool, and before the pile hole depth needs to penetrate the perched water layer, the method further includes: after encountering the perched water layer during rotary drilling, performing pile hole confluence, inserting a water pump into the pile hole for open drainage operation, and continuously draining water until the hole wall enters a stable seepage state.

[0014] According to one embodiment of the present invention, the silty clay wall retainer satisfies the following condition: when the silty clay wall retainer reaches saturation after absorbing water, the wall body still maintains a preset strength and exhibits a soft and elastic state.

[0015] According to one embodiment of the present invention, the method further includes: if multiple seepage points appear on the pile hole wall and the hole wall collapses severely due to insufficient compaction, the following steps are repeated:

[0016] The borehole was re-enlarged to below the perched water layer using a large-diameter drill bit.

[0017] Backfill the pile hole with silty clay to the ground surface;

[0018] A small-diameter drill bit was used to re-drill, forming a new silty clay wall.

[0019] According to one embodiment of the present invention, it further includes:

[0020] The freezing device is inserted into the vicinity of the seepage point of the silty clay retaining wall inside the pile hole to freeze the surface of the silty clay retaining wall.

[0021] According to one embodiment of the present invention, before drilling a hole at the original pile location using a large-diameter drilling tool, and before the pile hole depth needs to penetrate the perched water layer, the method further includes:

[0022] Indoor simulation experiments were conducted to determine the physical and mechanical properties and permeability characteristics of silty clay under target geological conditions, and to obtain the critical stable thickness of the silty clay retaining wall for guiding on-site construction.

[0023] According to one embodiment of the present invention, the step of conducting indoor simulation experiments to determine the physical and mechanical properties and permeability characteristics of silty clay under target geological conditions, and obtaining the critical stable thickness of the silty clay retaining wall to guide on-site construction, includes:

[0024] Uncirculated soil samples were collected from the perched water layer at the construction site, and the uncirculated soil samples were placed into and filled the test box.

[0025] The first experimental drilling tool was used to drill holes in the undisturbed soil sample to form multiple experimental pile holes;

[0026] Silty clay was selected as the filler. After filling the experimental pile hole, multiple second experimental drills with different outer diameters were used to re-drill, so that experimental protective walls of different thicknesses were formed in the experimental pile hole.

[0027] Water was injected into the undisturbed soil sample to saturate the soil between the test pile holes.

[0028] Observe and record the time required for the experimental retaining wall of different thicknesses to collapse when exposed to water;

[0029] The permeability of silty clay was tested using a standard permeameter to obtain the permeability coefficient of the silty clay.

[0030] Based on the permeability coefficient of silty clay, the critical stable thickness of the silty clay retaining wall, which is most suitable for guiding on-site construction, is determined from a variety of different thicknesses.

[0031] According to one embodiment of the present invention, before the undisturbed soil sample is injected with water to saturate the moisture content of the undisturbed soil sample between the experimental pile holes, the method further includes: taking a sample from a portion of the experimental pile holes in the experimental chamber and conducting a freezing experiment to determine the freezing time and freezing temperature of the surface layer of the experimental retaining wall.

[0032] According to one embodiment of the present invention, the backfilling of silty clay into the pile hole to the ground surface includes:

[0033] The pile holes were backfilled with silty clay in layers.

[0034] According to one embodiment of the present invention, the method further includes: after the surface layer of the silty clay wall is frozen, covering the pile hole opening.

[0035] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0037] Figure 1This is a schematic flowchart of a construction method for pile hole retaining wall for guiding and inhibiting stagnant water seepage in one embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the operation of a freezing device installed in a pile hole according to an embodiment of the present invention;

[0039] Figure 3 yes Figure 2 Top view at point A in the middle;

[0040] Figure 4 This is a schematic diagram of an indoor experimental apparatus according to an embodiment of the present invention.

[0041] in:

[0042] 1-Silty clay wall protection, 3-Perched layer, 4-Outer frame, 5-Annular copper pipe, 6-Temperature display unit, 7-Winder, 8-Compressor, 9-Snap fastener, 10-Water injection container, 11-Conduit, 12-Insertion tube, 13-First experimental drill bit, 14-Second experimental drill bit, 15-Experimental box, 16-Experimental pile hole, 17-Original soil sample, 601-Data cable, 602-Temperature sensor, 701-Sling, 801-Hose. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Rather, embodiments of the invention include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0044] The following is for reference. Figures 1 to 4 This invention describes a construction method for retaining walls of pile holes for guiding and suppressing the seepage of stagnant water, according to an embodiment of the invention.

[0045] According to an embodiment of the present invention, a construction method for pile hole retaining wall for guiding and inhibiting the seepage of stagnant water is described below:

[0046] Step S110: The perched water layer 3 is identified during the rotary drilling process.

[0047] In this embodiment, the location and thickness of the perched water layer 3 are confirmed by changes in drilling parameters and formation sampling during rotary drilling.

[0048] Step S120: Use a large-diameter drilling tool to drill a hole at the original pile location. The depth of the pile hole needs to penetrate the perched water layer 3.

[0049] In this embodiment, after confirming that water has been retained in the test pile in the water-retaining zone, the rotary drilling rig continues to drill through the entire water-retaining layer 3 using a large-diameter drill bit until it reaches the impermeable layer below. The diameter of the large-diameter drill bit is selected according to actual needs and is not limited thereto; for example, the diameter of the large-diameter drill bit is 1m.

[0050] Step S130: Backfill the pile hole with silty clay to the ground surface.

[0051] In this embodiment, silty clay refers to cohesive soil with a plasticity index between 10 and 17. Optionally, the moisture content of the silty clay is maintained within ±2%, exhibiting good plasticity and density. When backfilling with silty clay, the silty clay filler does not need to be too dense; it can be applied in layers. This results in good connectivity between the particles of the retaining wall soil, which helps to guide the seepage of stagnant water.

[0052] Step S140: Use a small-diameter drill bit to re-drill, forming an annular silty clay retaining wall 1 inside the pile hole.

[0053] In this embodiment, during the re-drilling stage, the rotary drilling rig uses a small-diameter drill bit to re-drill along the center of the original pile location, removing only the backfill soil in the central area, allowing the surrounding silty clay to naturally form a ring-shaped retaining wall of a certain thickness. The thickness of the silty clay retaining wall 1 is equal to half the difference between the diameters of the large-diameter drill bit and the small-diameter drill bit. The diameter of the small-diameter drill bit is selected according to actual needs and is not limited thereto; for example, the diameter of the small-diameter drill bit is 0.8m.

[0054] The beneficial effects of a construction method for pile hole retaining wall for guiding and suppressing stagnant water seepage according to an embodiment of the present invention are as follows: by adopting the process of "large-diameter hole enlargement + silty clay backfilling + small-diameter re-drilling" after identifying the stagnant water layer 3, a silty clay retaining wall 1 structure with a certain thickness is formed around the pile hole. The silty clay retaining wall 1 can play a role in slowing down and guiding seepage. Silty clay has a certain adsorption and cementing properties, which helps stabilize the soil structure. It can still maintain a certain strength after absorbing water saturation. Moreover, the material is widely available, inexpensive, green and environmentally friendly, effectively solving the problem of hole collapse caused by stagnant water seepage, without the need for additional investment in mechanical equipment.

[0055] In some embodiments, before step S120, when drilling a hole at the original pile location using a large-diameter drilling tool, and before the pile hole depth needs to penetrate the perched water layer 3, the method further includes:

[0056] In step S112, after encountering the stagnant water layer 3 during rotary drilling, the pile hole is drained by inserting a water pump into the pile hole for open drainage, and drainage is continuously carried out until the pile hole wall enters a stable seepage state.

[0057] In this embodiment, the water level in the pile hole is lowered by a water pump. After the water in the pile hole enters a slow seepage state, the hole wall is observed to confirm that it has entered a stable seepage state.

[0058] The silty clay retaining wall 1 meets the following conditions: when the silty clay retaining wall 1 reaches saturation after absorbing stagnant water, the wall body still maintains the preset strength and exhibits a flexible state. It does not collapse after effectively guiding the seepage of stagnant water. After meeting the above conditions, the silty clay retaining wall 1 does not collapse after effectively guiding the seepage of stagnant water.

[0059] In some embodiments, before step S120, which involves drilling a hole at the original pile location using a large-diameter drill bit, and the hole depth needs to penetrate the perched water layer 3, the method further includes:

[0060] Step S114: Conduct an indoor simulation experiment to determine the physical and mechanical properties and permeability characteristics of silty clay under the target geological conditions, and obtain the critical stable thickness of the silty clay retaining wall 1 to guide on-site construction.

[0061] In this embodiment, the critical stability thickness refers to the minimum thickness at which the silty clay retaining wall 1 can maintain structural integrity without significant deformation or collapse under simulated seepage conditions. The actual thickness of the silty clay retaining wall 1 constructed on site should not be less than this critical stability thickness.

[0062] Reference Figure 4 Step S114 involves conducting indoor simulation experiments to determine the physical and mechanical properties and permeability characteristics of silty clay under the target geological conditions, thereby obtaining the critical stable thickness of the silty clay retaining wall 1 for guiding on-site construction. Specifically, this includes:

[0063] Step S1141: Collect undisturbed soil sample 17 from the water-retaining layer 3 at the construction site, and fill the test box 15 with the undisturbed soil sample 17.

[0064] In this embodiment, the experimental chamber 15 is a glass box with dimensions of 45cm in length, 75cm in width, and 50cm in height, and the filling thickness of the undisturbed soil sample 17 is not less than 40cm.

[0065] Step S1142: Use the first experimental drill bit 13 to drill holes in the undisturbed soil sample 17 to form multiple experimental pile holes 16.

[0066] In this embodiment, the first experimental drill bit 13 can be a Luoyang shovel or a ring cutter for geotechnical experiments with a long shank welded on. The experimental pile holes 16 are used to simulate pile holes drilled by rotary drilling in the field. The number of experimental pile holes 16 is selected according to actual needs; for example, the number of experimental pile holes 16 is 8.

[0067] Step S1143: Select silty clay as filler and fill the experimental pile hole 16. Then, use multiple second experimental drills 14 with different outer diameters to re-drill, so that experimental protective walls of different thicknesses are formed inside the experimental pile hole 16.

[0068] In this embodiment, the second experimental drill bit 14 also uses a Luoyang shovel, and its outer diameter is smaller than that of the first experimental drill bit 13.

[0069] Step S1144: Inject water into the undisturbed soil sample 17 to saturate the water content of the undisturbed soil sample 17 between the experimental pile holes 16.

[0070] In this embodiment, the water injection device includes a water injection container 10, a conduit 11, and an insertion tube 12. The two ends of the conduit 11 are connected to the two ends of the water injection container 10 and the insertion tube 12, respectively. During the simulated permeable water seepage experiment, the height of the water injection container 10 is increased to simulate a water pressure difference. After inserting the insertion tube 12 into the undisturbed soil sample 17, water is slowly injected around the perimeter of the experimental chamber 15 until the soil around the experimental pile hole 16 reaches saturation. It should be noted that, to improve the reliability of the design parameters for the silty clay retaining wall structure, a standard permeameter is used to test the permeability of the silty clay during the indoor simulation experiment. The results of both tests are cross-validated to obtain a more accurate permeability coefficient.

[0071] Step S1145: Take a sample of part of the experimental pile hole 16 in the experimental chamber 15 and conduct a freezing test to determine the freezing time and freezing temperature of the surface layer of the experimental protective wall.

[0072] In this embodiment, a freezing experiment was conducted to determine the temperature control parameters and time period required for effective freezing under field conditions, without imposing specific limitations. For example, the freezing temperature was -5°C, and the experimental results showed that a stable frozen layer could form on the surface of the experimental protective wall within 48 hours.

[0073] Step S1146: Observe and record the time required for the experimental retaining wall to collapse when exposed to water at different thicknesses.

[0074] Step S1147: Use a standard permeameter to test the permeability of silty clay and obtain the permeability coefficient of silty clay.

[0075] Step S1148: Based on the permeability coefficient of silty clay, determine the most suitable critical stable thickness of the silty clay retaining wall 1 for guiding on-site construction from a variety of different thicknesses.

[0076] In this embodiment, the seepage erosion deformation of the experimental retaining walls in each experimental pile hole 16 under different thickness conditions was measured, and the time when significant deformation or collapse occurred was established to establish the relationship between retaining wall thickness and stability. The selection of the silty clay retaining wall 1 filler material cannot solely consider its permeability coefficient; that is, a low permeability coefficient should not be pursued blindly, as it easily adheres to the drill bit and is difficult to form a retaining wall. Conversely, a material with excessively high permeability should not be selected, as it easily collapses. Under the premise of a suitable permeability coefficient, the most suitable critical stable thickness of the silty clay retaining wall 1 is selected from various thicknesses.

[0077] The following is a specific indoor simulation experiment process.

[0078] Experimental equipment: Experiment box 15, water injection container 10, experimental drill, timer, precision electronic scale.

[0079] Experimental materials: silt, silty clay, red clay, lime, cement.

[0080] Experimental procedure:

[0081] The experimental chamber 15 is pre-laid with a 20cm thick layer of undisturbed soil sample 17, and different experimental material samples are inserted in the middle. Each material sample has a diameter of 7cm, a height of 5cm, and a thickness of 2.5cm. Timing starts after the immersion experiment reaches saturation, and the data is recorded every hour until each experimental material sample reaches its plastic limit.

[0082] Experiment Summary

[0083] As shown in Table 1, six experimental samples were made using the above five experimental materials. The results were recorded every hour, and the sample strength was then checked. In the first hour, the silty clay wall became soft and basically lost its strength. After two hours, the 3:7 lime and silty clay samples lost their strength. After six hours, only the cement, cement soil, lime, and silty clay samples in test box 15 still did not become soft. Based on cost-effectiveness, silty clay is proposed to be selected as the backfill material on site.

[0084] Table 1

[0085]

[0086] In some embodiments, the method further includes: if multiple seepage points appear on the pile hole wall and the hole wall collapses severely due to insufficient compaction, repeating the following steps:

[0087] Step S151: Use a large-diameter drill bit to re-enlarge the hole to below the perched water layer 3.

[0088] Step S152: Backfill the pile hole with silty clay to the ground surface.

[0089] Step S153: Drill again using a small-diameter drill bit to form a new silty clay wall 1.

[0090] Steps S151 to S153 can be repeated until the pile hole reaches a stable state without free seepage.

[0091] In some embodiments, a construction method for retaining the wall of a pile hole for guiding and inhibiting the seepage of stagnant water further includes:

[0092] Step S160: Insert the freezing device into the vicinity of the seepage area of ​​the silty clay wall 1 inside the pile hole to freeze the surface of the silty clay wall 1.

[0093] In this embodiment, a freezing device is inserted into the pile hole to freeze the surface layer of the silty clay retaining wall 1, forming a frozen reinforcement zone. Afterwards, an insulation pad is placed over the pile hole surface. The inventors discovered that, under existing technologies in cast-in-place pile construction, the pile hole cannot remain in place for extended periods. Concrete pumping vehicles typically travel at night for convenience, causing the pouring of most pile holes to be delayed until the evening. Pouring water-bearing holes at night easily leads to poor visibility, fatigue, and numerous quality problems. This step overcomes the problem of the pile hole not being able to be left open due to seepage. By freezing the pile hole, the retention time can be arbitrarily extended, allowing for concentrated pouring during the day, improving pouring efficiency and quality.

[0094] The specific type of refrigeration unit is determined based on actual needs and is not limited thereto. In one example, combining... Figure 2 and Figure 3 As shown, the refrigeration unit includes an outer frame 4, an annular copper pipe 5, a temperature display unit 6, a winch 7, a compressor 8, a data cable 601, a temperature sensor 602, a hoisting cable 701, and a flexible hose 801. The annular copper pipe 5 is located inside the outer frame 4 and contains refrigerant. The annular copper pipe 5 acts as an evaporator, absorbing heat from the surrounding air. The winch 7 is connected to the outer frame 4 via the hoisting cable 701. The compressor 8 delivers refrigerant to the annular copper pipe 5 via the flexible hose 801. The winch 7 controls the raising and lowering of the outer frame 4, positioning it at its depth within the pile hole. The temperature sensor 602 is located at the center of the annular copper pipe 5 and is used to measure the ambient temperature. The temperature display unit 6 is located outside the pile hole and is connected to the temperature sensor 602 via the data cable 601, displaying the ambient temperature inside the pile hole in real time. In one specific embodiment, as shown... Figure 3 As shown, the freezing device also includes a clip 9, which connects the temperature sensor 602 to the annular copper tube 5. The outer diameter of the annular copper tube 5 is matched with the inner diameter of the pile hole to achieve a good freezing effect.

[0095] When the freezing device is in use, the outer frame 4 extends into the seepage area, the compressor 8 is started, and the operation stops when the reading on the temperature display unit 6 drops to -5℃. The pile hole is then covered. When the temperature display unit 6 shows a temperature above 0℃, the compressor 8 is turned on again to keep the seepage area frozen.

[0096] In another example, the refrigeration unit can also use pre-made ice plates to replace the compressor 8 and the annular copper tube 5, which has the advantages of easy operation and low cost.

[0097] In some embodiments, a construction method for retaining the wall of a pile hole for guiding and inhibiting the seepage of stagnant water further includes:

[0098] Step S170: Pour concrete into the pile hole.

[0099] In this embodiment, the concrete temperature can be appropriately increased before pouring to thaw the frozen state of the retaining wall. The concrete must be made of frost-resistant cement, such as silicate cement. Furthermore, after the pile body is poured, the test blocks prepared from it must also be solidified at -5°C. Only after the test blocks pass the strength test can they be used on a large scale.

[0100] It should be noted that in the description of this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0101] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0102] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0103] In the description of this invention, the terms "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0104] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0105] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0106] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A construction method for pile hole wall protection for dredging, inhibiting stagnant water seepage, characterized in that, Comprise: Rotary drilling process identifies water layer (3); Large diameter drilling tool is used to form hole at original pile position, and pile hole depth needs to penetrate water layer (3); Silty clay is backfilled in pile hole to ground surface; Small diameter drilling tool is used to re-drill, and annular silty clay protection wall (1) is formed in pile hole, wherein the silty clay protection wall (1) meets the following conditions: when the silty clay protection wall (1) is saturated after adsorbing water, the wall still maintains preset strength and presents soft elastic state.

2. The construction method for pile hole wall protection for dredging, inhibiting stagnant water seepage according to claim 1, characterized in that, Before the large diameter drilling tool is used to form hole at original pile position, and the pile hole depth needs to penetrate water layer (3), the method further comprises: after encountering water layer (3) in rotary drilling process, pile hole is converged, water pump is inserted into pile hole to carry out open drainage operation, and drainage is continuously carried out until pile hole wall enters stable seepage state.

3. The construction method for pile hole wall protection for dredging, inhibiting stagnant water seepage according to claim 1, characterized in that, Further comprise: If multiple point seepage appears on pile hole wall, and hole wall collapses seriously due to insufficient compaction, the following steps are repeatedly executed: Large diameter drilling tool is used to re-expand hole to below water layer; Silty clay is backfilled in pile hole to ground surface; Small diameter drilling tool is used to re-drill again, and new silty clay protection wall (1) is formed.

4. The construction method for pile hole wall protection for water seepage dredging and inhibition according to claim 1, characterized in that, Further comprise: Freezing device is inserted into the vicinity of seepage part of silty clay protection wall (1) in pile hole, and surface layer of silty clay protection wall (1) is frozen.

5. The construction method for pile hole wall protection for water seepage dredging and inhibition according to claim 1, characterized in that, Before the large diameter drilling tool is used to form hole at original pile position, and the pile hole depth needs to penetrate water layer (3), the method further comprises: Indoor simulation experiment is carried out, physical and mechanical properties and permeability characteristics of silty clay under target geological conditions are measured, and critical stable thickness of the silty clay protection wall (1) guiding field construction is obtained.

6. The construction method for pile hole wall protection for dredging, inhibiting stagnant water seepage according to claim 5, characterized in that, The indoor simulation experiment is carried out, the physical and mechanical properties and the permeability characteristics of the silty clay under the target geological conditions are measured, and the critical stable thickness of the silty clay protection wall (1) guiding the field construction is obtained, comprising: The undisturbed soil sample (17) is collected in the water layer (3) at the construction site, and the undisturbed soil sample (17) is filled into and filled in the experimental box (15); The first experimental drilling tool (13) is used to form hole in the undisturbed soil sample (17), and a plurality of experimental pile holes (16) are formed; Silty clay is selected as the filler, and after the experimental pile hole (16) is filled, a plurality of second experimental drilling tools (14) with different outer diameters are used to re-drill, so that the experimental pile hole (16) forms an experimental protection wall with different thicknesses; Water is injected into the undisturbed soil sample (17) to saturate the undisturbed soil sample (17) between the experimental pile holes (16); The time required for the experimental protection wall to collapse in different thicknesses is observed and recorded; The standard permeameter is used to test the permeability of the silty clay, and the permeability coefficient of the silty clay is obtained; According to the permeability coefficient of the silty clay, the most suitable critical stable thickness of the silty clay protection wall (1) guiding the field construction is obtained from a plurality of different thicknesses.

7. The construction method for pile hole wall protection for dredging, inhibiting stagnant water seepage according to claim 6, characterized in that, Before the undisturbed soil sample (17) is injected with water to saturate the undisturbed soil sample (17) between the experimental pile holes (16), the method further comprises: taking part of the sample of the experimental pile hole (16) in the experimental box (15), carrying out freezing experiment, and determining the freezing time and freezing temperature of the surface layer of the experimental protection wall.

8. The construction method for pile hole wall protection for water seepage dredging and inhibition according to claim 1, characterized in that, The silty clay is backfilled in the pile hole by layering and throwing. ​ 9. The construction method for pile hole wall protection for water seepage dredging and inhibition according to claim 4, characterized in that, Also included are: After the surface layer of the silty clay retaining wall (1) is frozen, cover the pile hole opening.

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