Construction method of triaxial cement-soil mixing pile water-stop curtain in pebble layer
Through a long auger drilling rig, it drills and pours the soil three times during the construction of the pebble layer, and solves the problems of drilling caused by incomplete soil collapse, achieving more efficient construction quality and lower costs and pollution.
Patent Information
- Application Number
- CN202411299928.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2044-09-18
AI Technical Summary
In the prior art, when the thick cobblestone layer is constructed, conventional construction methods cannot achieve the ideal effect, and there are situations where incomplete soil pouring lead to drilling, drilling, and drilling cannot be drilled during pile formation.
A long auger drilling rig is used to drill down and pour soil three times, to 0.5m below the top, bottom and curtain design elevation of the pebble layer to ensure that the earth and pebble of the pebble layer are poured out, avoiding the collapse of the hole wall and ensuring uniform soil quality.
By ensuring the complete pouring of the pebble layer, problems such as stuck drills and buried drills are avoided, the construction quality of the water-stop curtain is improved, the construction cost and construction period are reduced, and environmental pollution is reduced.
Smart Images
Figure CN119041407B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of construction engineering, and particularly relates to a construction method for a water-stop curtain of a triaxial cement-soil mixing pile in a pebble layer. Background Art
[0002] At present, the conventional construction methods for water-stop curtains (a continuous water-stop structure used to prevent or reduce the inflow of groundwater from the side walls and bottom of a foundation pit into the foundation pit) for crossing pebble layers are high-pressure jet grouting piles, diaphragm walls, and triaxial mixing piles. Among them, the construction process of the triaxial mixing pile water-stop curtain is to first form a hole, and then use a mixing pile machine to spray cement and other reinforcement materials into the soil in the pile hole and fully mix them. A series of physical and chemical reactions occur between the cement and the soil, making the soil harden and increasing the foundation strength, resulting in a water-stop effect, thereby forming a water-stop curtain to control the permeability of groundwater. For pebble layer areas, when selecting a triaxial mixing pile for water-stop, various construction methods are adopted, such as: the method of rotary drilling and leading hole - triaxial mixing pile, the method of long spiral leading hole - triaxial mixing pile, the method of impact drilling and leading hole - triaxial mixing pile, etc.
[0003] However, when constructing in a thick and large pebble layer (a pebble layer with a large thickness and large particles), the conventional construction methods cannot achieve an ideal construction effect.
[0004] When constructing a curtain using the method of rotary drilling and leading hole - triaxial mixing pile, after the rotary drilling rig leads the hole, the triaxial drilling rig can form a pile under the geological conditions of a thick and large pebble layer and can achieve a good water-stop effect. However, the rotary drilling and leading hole process has disadvantages such as high noise, high construction cost, large environmental pollution, and long construction time. At the same time, the leading hole spacing is small. After completing the first round of leading holes and then leading holes again, there is a risk of collapse of the hole wall between the two leading holes, and the construction risk is relatively large.
[0005] When constructing a curtain using the method of long spiral drilling rig leading hole - triaxial mixing pile, the long spiral leading construction has advantages such as simple construction process, low cost, small environmental pollution, and low noise. However, in the actual process, after the long spiral drilling rig leads the hole to the depth of the curtain pile once and then reverses the drill to dump the soil, the soil dumping is incomplete. According to the observation of the soil volume dumped to the ground surface at the site, the soil dumping volume is about 1 / 3 of the theoretical volume. Especially in the pebble layer part, there are basically no pebbles in the dumped soil. Therefore, during the process of forming a pile with a triaxial mixing pile machine, there are situations such as drill jamming, drill burying, and inability to drill down after partially forming a pile to the pebble layer part. Summary of the Invention
[0006] (I) Technical Problems to be Solved
[0007] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a construction method for a water-stop curtain of a triaxial cement-soil mixing pile in a pebble layer, which solves the technical problems of drill jamming, drill burying, and inability to drill down during the pile-forming process caused by incomplete soil dumping in the prior art.
[0008] (2) Technical Solution
[0009] To achieve the above object, the main technical solutions adopted in the present invention include:
[0010] The present invention provides a construction method for a water-stop curtain of a triaxial cement-soil mixing pile in a pebble layer, including the steps of:
[0011] S1. Extend the drill pipe of the long auger drill above the position of the first retaining pile point, confirm the perpendicularity of the drill pipe, and ensure that the hole-forming perpendicularity meets the design specifications and requirements.
[0012] S2. Sequentially drill holes downward through the long auger drill to the top position of the pebble layer, the bottom position of the pebble layer, and the target position 0.5 m below the designed elevation of the curtain; and dump soil respectively when reaching the top position, the bottom position, and the target position; the long auger drill withdraws from this retaining pile point and proceeds with the hole-forming operation for the next retaining pile point.
[0013] S3. Backfill the drill cuttings formed by the first soil dumping into the pile hole, and then perform the pile-forming operation through the triaxial mixing pile machine.
[0014] Further, step S2 includes the steps of:
[0015] S21. Guide the hole downward from the ground through the drill pipe to the top position of the pebble layer, keep the drill pipe rotating continuously at this position for 10 - 20 s, stop the rotation of the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the first soil dumping.
[0016] S22. Lower the drill pipe to the bottom of the hole and continue to guide the hole downward through the pebble layer to reach the bottom position, keep the drill pipe rotating continuously at this position for 10 - 20 s, stop the rotation of the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the second soil dumping.
[0017] S23. Lower the drill pipe to the bottom of the hole and continue to drill the hole to reach the target position 0.5 m below the designed elevation of the curtain, keep the drill pipe rotating continuously at this position for 10 - 20 s, stop the rotation of the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the third soil dumping; the long auger drill withdraws from this retaining pile point and proceeds with the hole-forming operation for the next retaining pile point.
[0018] Further, in step S21, the downward drilling speed of the drill pipe during hole guiding is 1 - 1.2 m / min, and the drill pipe lifting speed during soil dumping is 2 - 3.3 m / min.
[0019] Further, in step S22, the downward drilling speed of the drill pipe during hole guiding is 2 - 2.5 m / min, and the drill pipe lifting speed during soil dumping is 5 - 6 m / min.
[0020] Further, in step S23, the downhole drilling speed during the drill pipe pilot hole drilling is 2.5 - 3 m / min, and the uphole drilling speed during the drill pipe soil dumping is 3.5 - 4 m / min.
[0021] Further, before performing step S1, construction preparation work including site leveling, positioning and setting out, and determining the pile foundation pilot hole sequence needs to be carried out.
[0022] Further, step S5 includes:
[0023] S31. Backfill the drill cuttings formed by the first soil dumping into the pile hole until reaching the top position of the pebble layer to prevent the collapse of the pebble layer. Among them, the backfilled drill cuttings do not contain pebble parts.
[0024] S32. The three - axis mixing pile machine is positioned, and the center of its drill pipe is aligned with the center of the positive pile hole; meanwhile, prepare the cement slurry according to the design requirements, and check whether the specific gravity of the prepared cement slurry reaches the design requirements through a mud specific gravity meter. If the specific gravity is lower than the design requirements, it shall be discarded; if the specific gravity reaches the design requirements, the cement slurry is sieved and then injected into the aggregate hopper of the three - axis mixing pile machine.
[0025] S33. Cut the soil downward along the axial direction of the pile hole through the drill bit of the three - axis mixing pile machine, spray the cement slurry into the pile hole by the three - axis mixing pile machine, and the blades of the drill pipe of the three - axis mixing pile machine rotate to cut and stir the soil mass until reaching the bottom of the pile hole.
[0026] S34. The drill pipe of the three - axis mixing pile machine is lifted to the ground. During the lifting process, the three - axis mixing pile machine continuously sprays the cement slurry into the pile hole, and the blades of the drill pipe of the three - axis mixing pile machine rotate to cut and stir the soil mass; repeat step S33.
[0027] S35. Repeat steps S33 and S34 until the pile is completed.
[0028] Further, in step S33, after the drill pipe of the three - axis mixing pile machine reaches the bottom of the pile hole, it continuously stirs at the bottom position of the pile hole for 10 - 15 s and then stops, and the three - axis mixing pile machine continuously sprays the cement slurry into the pile hole.
[0029] Further, in step S33, the drilling speed of the three - axis mixing pile machine is 1.4 - 1.5 m / min, and the slurry spraying pressure is 0.4 - 0.6 Mpa; in step S34, the lifting speed of the three - axis mixing pile machine is 1.4 - 1.5 m / min, and the slurry spraying pressure is 0.4 - 0.6 Mpa.
[0030] Further, in S32, after the drill pipe of the three - axis mixing pile machine is aligned, confirm that the verticality error of its drill pipe does not exceed 1%.
[0031] (III) Beneficial effects
[0032] The beneficial effects of the present invention are as follows:
[0033] A construction method of a triaxial cement-soil mixing pile water-stop curtain in a pebble layer provided by the present invention involves three times of drilling down by a long auger drill and three times of soil dumping. For the first time, drill down to the top position of the pebble layer and dump the soil at the top of the pebble layer; then, for the second time, drill down to the bottom of the pebble layer and dump part of the pebbles in the pebble layer onto the ground. Since most of the soil has been dumped during the first drill-up and soil dumping, the second drill-down for hole guiding only penetrates the pebble layer, so most of the pebbles can be dumped onto the ground during the second drill-up and soil dumping; finally, for the third time, drill down to 0.5 m below the designed elevation of the curtain, and then conduct the third reverse drilling and soil dumping to ensure that all the pebbles can be completely dumped out, ensuring uniform soil quality, being beneficial to the water-stop quality of the curtain, and avoiding situations such as drill jamming, drill burying, and inability to drill down for the subsequent triaxial mixing pile machine. Moreover, drilling down to 0.5 m below the designed elevation of the curtain for the third time can solve the problem that part of the pebbles cause the collapse of the hole wall and accumulate at the bottom of the hole due to the groundwater flow after the hole is formed, resulting in insufficient length of the triaxial pile. On the basis of ensuring the construction of the curtain pile, compared with the rotary drilling for hole guiding, it can reduce the construction cost, shorten the construction period, and reduce environmental pollution at the same time. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 It is a flow chart of a construction method of a triaxial cement-soil mixing pile water-stop curtain in a pebble layer in a specific embodiment of the present invention.
[0035] Figure 2 It is a specific flow chart of step S2 in a specific embodiment of the present invention.
[0036] Figure 3 It is a specific flow chart of step S5 in a specific embodiment of the present invention. SPECIFIC EMBODIMENTS
[0037] In order to better understand the above technical solutions, the exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more clear and thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0038] As Figure 1 shown, a construction method of a triaxial cement-soil mixing pile water-stop curtain in a pebble layer provided by a specific embodiment of the present invention includes the steps:
[0039] S1. Carry out construction preparation work such as site leveling, positioning and setting out, and determining the order of pilot holes for pile foundations; then the long auger drill rig is positioned, and the drill pipe of the long auger drill rig extends above the position of the first retaining pile point. Confirm the verticality of the drill pipe to ensure that the hole-forming verticality meets the design specifications and requirements.
[0040] S2. Use the long auger drill rig to successively drill down to the top position of the cobblestone layer, the bottom position of the cobblestone layer, and the target position 0.5 m below the curtain design elevation; and dump soil respectively when reaching the top position, the bottom position, and the target position; the long auger drill rig withdraws from this retaining pile point and proceeds with the hole-forming operation for the next retaining pile point.
[0041] S3. Backfill the drill cuttings into the pile hole, and then use the three-axis mixing pile rig to carry out the construction of the cement-soil mixing pile.
[0042] Specifically, use the long auger drill rig to drill down three times and dump soil three times. The first time, drill down to the top position of the cobblestone layer and dump the soil at the top of the cobblestone layer; then the second time, drill down to the bottom of the cobblestone layer and dump part of the cobblestones on the ground. Since most of the soil has been dumped out during the first drill rod lifting and soil dumping, the second drill-down and pilot hole only penetrate the cobblestone layer. Therefore, most of the cobblestones can be dumped to the ground during the second drill rod lifting and soil dumping; finally, the third time, drill down to 0.5 m below the curtain design elevation, and then carry out the third reverse drill and soil dumping to ensure that all the cobblestones can be completely dumped out, ensuring uniform soil quality, being beneficial to the curtain water-stop quality, and at the same time avoiding the situations of drill rod jamming, drill rod burying, and inability to drill down for the subsequent three-axis mixing pile rig. Moreover, drilling down to 0.5 m below the curtain design elevation for the third time can solve the problem that after hole-forming, part of the cobblestones cause the collapse of the hole wall and pile up at the bottom of the hole due to the groundwater flow, resulting in insufficient length of the three-axis formed pile. On the basis of ensuring the construction of the curtain pile, compared with the rotary drilling and pilot hole, it can reduce the construction cost, shorten the construction period, and reduce environmental pollution at the same time.
[0043] Furthermore, as Figure 2 shown, step S2 includes:
[0044] S21. Start the long auger drill rig and use the drill pipe to drill down from the ground to the top position of the cobblestone layer. At this position, keep the drill pipe rotating for 10 - 20 s, stop the rotation of the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the first soil dumping. Among them, the downward drilling speed of the drill pipe during pilot hole drilling is 1 - 1.2 m / min, and the drill pipe lifting speed during soil dumping is 2 - 3.3 m / min. Design the downward drilling speed according to the soil layer above the cobblestone layer to ensure the stability of the hole wall during the downward drilling process; the drill pipe lifting speed is designed according to the drill cuttings formed by the upper soil layer and the earthwork volume of the drill cuttings to ensure that the drill cuttings can be dumped out to the ground to the greatest extent.
[0045] S22. Lower the drill pipe to the bottom of the hole and continue to drill downward through the pebble layer to reach the bottom position. At this position, rotate the drill pipe continuously for 10 - 20 s, stop rotating the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the second soil dumping. Among them, the downward drilling speed when the drill pipe is drilling is 2 - 2.5 m / min, and the lifting speed of the drill pipe when dumping soil is 5 - 6 m / min. According to the thickness of the pebble layer and the diameter of the pebble particles, maintaining the downward drilling speed at 2 - 2.5 m / min can ensure the construction speed while further considering the impact on the drill pipe to ensure that the drill pipe is not damaged. The diameter of the pebble particles is relatively large, and the difficulty of soil dumping is relatively low, so the lifting speed during soil dumping can be faster, and a lifting speed of 5 - 6 m / min is adopted.
[0046] S23. Lower the drill pipe to the bottom of the hole and continue to form a hole to a position 0.5 m below the curtain design elevation to reach the target position. At this position, rotate the drill pipe continuously for 10 - 20 s, stop rotating the drill pipe and lift the drill pipe by 1 - 2 m, rotate the drill pipe in the reverse direction and lift the drill pipe out of the ground to complete the third soil dumping; the long - auger drill can then evacuate from this support pile point. Among them, the downward drilling speed when the drill pipe is drilling is 2.5 - 3 m / min, and the lifting speed of the drill pipe when dumping soil is 3.5 - 4 m / min. The third downward drilling needs to directly reach the target depth, and the difficulty of forming a hole in the soil layer below the pebble layer is lower, so a faster drilling speed of 2.5 - 3 m / min is adopted to ensure the construction speed; some pebbles may remain after the second soil dumping, and the third soil dumping needs to completely remove the pebbles from the pile hole. Considering the construction speed at the same time, the lifting speed of 3.5 - 4 m / min is adopted. After the long - auger drill evacuates from this support pile point, the hole - forming operation for the next support pile point can be carried out.
[0047] Further, as Figure 3 shown, step S5 includes:
[0048] S31. Use an excavator to backfill the drill cuttings formed by the first soil dumping into the pile hole until reaching the top position of the pebble layer to prevent the pebble layer from caving in. Among them, the backfilled drill cuttings do not contain the pebble part.
[0049] S32. The three - axis mixing pile machine is in place, and the center of its drill pipe is aligned with the center of the positive pile hole, and then it is confirmed that the verticality error of its drill pipe does not exceed 1%; at the same time, prepare the cement slurry according to the design requirements, and check whether the specific gravity of the prepared cement slurry reaches the design requirements through a mud specific gravity meter. If the specific gravity is lower than the design requirements, it shall be discarded; if the specific gravity reaches the design requirements, the cement slurry shall be sieved and then injected into the aggregate hopper of the three - axis mixing pile machine. Specifically, the design requirements include the cement used, the cement content in the active area, the cement content in the passive area, the water - cement ratio of the cement slurry, and the admixture.
[0050] S33. The drill bit of the triple-axis mixing pile rig cuts the soil downward along the axial direction of the pile hole. The triple-axis mixing pile rig sprays cement slurry into the pile hole, and the blades of the drill pipe of the triple-axis mixing pile rig rotate to cut and stir the soil mass until the bottom of the pile hole. After the drill pipe of the triple-axis mixing pile rig reaches the bottom of the pile hole, at the bottom position of the pile hole, its drill pipe continuously stirs for 10 - 15 s and then stops, and the triple-axis mixing pile rig continuously sprays cement slurry into the pile hole. Among them, the drilling speed of the triple-axis mixing pile rig is 1.4 - 1.5 m / min, and the slurry spraying pressure is 0.4 - 0.6 Mpa to ensure that the rated slurry volume is evenly distributed within the pile body length range and the grouting volume in the pile is sufficient.
[0051] S34. The drill pipe of the triple-axis mixing pile rig is lifted to the ground. During the lifting process, the triple-axis mixing pile rig continuously sprays cement slurry into the pile hole, and the blades of the drill pipe of the triple-axis mixing pile rig rotate to cut and stir the soil mass. The drilling speed of the triple-axis mixing pile rig is 1.4 - 1.5 m / min, and the slurry spraying pressure is 0.4 - 0.6 Mpa to ensure that the rated slurry volume is evenly distributed within the pile body length range and the grouting volume in the pile is sufficient.
[0052] S35. After repeating step S33, continue with step S34 to complete the pile formation through two sprayings and two stirrings.
[0053] S36. Inject an appropriate amount of normal temperature water into the aggregate hopper, clean the residual cement slurry and other sundries on the aggregate hopper and the drill pipe, then move to the next pile hole and repeat steps S31 - S35.
[0054] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.
[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication inside two components or the interaction relationship between two components. 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.
[0056] In the present invention, unless otherwise clearly specified and defined, a first feature being "on" or "under" a second feature may mean that the first and second features are in direct contact, or that the first and second features are indirectly in contact via an intermediate medium. Further, a first feature being "above", "over" and "on top of" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. A first feature being "under", "below" and "beneath" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.
[0057] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples", etc., mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.
[0058] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill 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 a pebble layer triaxial cement soil mixing pile water-stop curtain, characterized in that: Includes steps: S1. Extend the drill rod of the long spiral drill to the position above the first support pile, confirm the verticality of the drill rod, and ensure that the verticality of the hole meets the design specifications and requirements; S2, drilling holes downwards to the top position of the pebble layer, the bottom position of the pebble layer and the target position 0.5m below the curtain design elevation in sequence by using a long spiral drill; and dumping soil when reaching the top position, the bottom position and the target position respectively; The long spiral drill rig withdraws from the supporting pile point and carries out the drilling operation at the next supporting pile point; S3, backfilling the drill residue formed by the first soil dumping into the pile hole, and then performing pile forming operation by a three-axis pile mixing machine; Step S2 comprises the steps of: S21, using a drill rod to drill a hole from the ground to the top of the pebble layer, the drill rod is rotated continuously for 10 to 20 seconds at this position, the drill rod is stopped and lifted up by 1 to 2 meters, the drill rod is rotated in the opposite direction and lifted up to the ground, and the first earth removal is completed; wherein, the drilling speed when the drill rod is used to drill the hole is 1 to 1.2 m / min, and the drilling speed when the drill rod is used to remove the earth is 2 to 3.3 m / min; S22, the drill rod is lowered to the bottom of the hole and continues to be led downward until it passes through the pebble layer and reaches the bottom position, at which position the drill rod is continuously rotated for 10 to 20 seconds, the drill rod is stopped and the drill rod is lifted up by 1 to 2 meters, the drill rod is rotated in the opposite direction and lifted up to the ground, completing the second earth removal; wherein, the lowering speed of the drill rod when leading the hole is 2 to 2.5 meters per minute, and the lifting speed of the drill rod when earth removal is 5 to 6 meters per minute; S23. The drill rod is lowered to the bottom of the hole and continues to drill downward until it reaches the target position 0.5m below the curtain design elevation. At this position, the drill rod continues to rotate for 10 to 20 seconds, the drill rod rotation is stopped and the drill rod is lifted up 1 to 2m, the drill rod is rotated in the opposite direction and lifted up to the ground to complete the third earth pouring. The long spiral drill rig withdraws from the supporting pile point and performs the hole drilling operation at the next supporting pile point. Among them, the drilling speed when the drill rod is leading the hole is 2.5 to 3m / min, and the drilling speed when the drill rod is pouring the soil is 3.5 to 4m / min.
2. The construction method of the pebble layer tri-axial cement soil mixing pile water-stop curtain as claimed in claim 1, characterized in that: Before performing step S1, construction preparation work including site leveling, positioning and setting out, and determining the sequence of pile foundation drilling is required.
3. The construction method of the pebble layer tri-axial cement soil mixing pile water-stop curtain as claimed in claim 1, characterized in that: Step S3 includes: S31, backfilling the drill residue formed by the first soil dumping into the pile hole to the top of the pebble layer; S32, the three-axis pile mixing machine is in place, and the center of its drill rod is aligned with the center of the pile hole; at the same time, cement slurry is prepared according to the design requirements, and the specific gravity of the prepared cement slurry is checked by a mud density meter to see whether it meets the design requirements. If the specific gravity is lower than the design requirements, it will be discarded; if the specific gravity meets the design requirements, the cement slurry will be screened and injected into the aggregate hopper of the three-axis pile mixing machine; S33, cutting the soil downward along the axial direction of the pile hole by the drill bit of the three-axis mixing pile machine, spraying cement slurry into the pile hole by the three-axis mixing pile machine, and rotating the blades of the drill rod of the three-axis mixing pile machine to cut and mix the soil until the bottom of the pile hole; S34, the drill rod of the three-axis mixing pile machine is lifted to the ground. During the lifting process, the three-axis mixing pile machine continuously sprays cement slurry into the pile hole, and the blades of the drill rod of the three-axis mixing pile machine rotate to cut and mix the soil; S35, repeat steps S33 and S34 until the pile is completed.
4. The construction method of the pebble layer triaxial cement soil mixing pile water-stop curtain as claimed in claim 3, characterized in that: In step S33, after the drill rod of the three-axis pile mixing machine reaches the bottom of the pile hole, the drill rod continues to stir at the bottom of the pile hole for 10 to 15 seconds, and continues to spray cement slurry into the pile hole.
5. The construction method of the pebble layer triaxial cement soil mixing pile water-stop curtain as claimed in claim 3, characterized in that: In step S33, the drilling speed of the three-axis pile mixing machine is 1.4-1.5 m / min, and the shotcrete pressure is 0.4-0.6 Mpa; In step S34, the lifting speed of the three-axis mixing pile machine is 1.4-1.5 m / min, and the shotcrete pressure is 0.4-0.6 MPa.
6. The construction method of the pebble layer triaxial cement soil mixing pile water-stop curtain as claimed in claim 3, characterized in that: In S32, after the drill rod of the three-axis pile mixing machine is centered, it is confirmed that the verticality error of the drill rod does not exceed 1%.