A pile driving method for quicksand strata

Abstract

The present invention relates to the field of construction and specifically discloses a piling method for quicksand formations, comprising the steps of drilling pile holes; installing steel pipes; clearing quicksand; grouting; installing oblique steel pipe piles, preparing a plurality of oblique steel pipe piles, obliquely inserting and installing the piles into the quicksand formation, and welding the upper ends of the oblique steel pipe piles to the upper ends of the steel pipes to form a pile base; installing steel casings; and forming engineering piles. In step 5, this solution employs a plurality of oblique steel pipe piles, forming a combination of straight and oblique piles. The steel pipes and oblique steel pipe piles provide excellent wall protection.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a piling method for quicksand strata. Background Art

[0002] Quicksand is a unique terrain characterized by water-saturated, loose sandy soil, primarily composed of silt and fine sand, typically found in rivers, lakes, or old riverbeds. It liquefies and flows under the influence of vibration or hydrodynamic pressure, making construction in this stratum extremely dangerous. To ensure project quality, pile foundations are necessary. However, pile foundation construction in quicksand is highly susceptible to collapse and is difficult to create.

[0003] The commonly used piling method now is to first drive a circle of high-pressure rotary jet piles around the construction and installation of the pile foundation, and then inject concrete into the high-pressure rotary jet piles to reinforce the quicksand around the high-pressure rotary jet piles; and then carry out the pile driving construction of the pile foundation. In the above process, although the use of high-pressure rotary jet piles for high-pressure concrete injection can fix the quicksand to a certain extent, the quicksand stratum still has the problem of lateral thrust, which makes the pile foundation prone to tilting or even breaking during the construction process; at the same time, when the method of grouting first and then piling is used, the slurry flows along the gaps, and it is difficult to ensure that the pile foundation is filled with slurry, which makes it difficult to ensure the grouting effect, and the consumption of concrete is also particularly large, resulting in high construction costs. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a pile driving method for quicksand strata to solve the problem that quicksand strata have loose fluidity, which in turn causes lateral thrust to the pile foundation during pile foundation construction, easily causing the engineering piles to tilt or even break during the construction process.

[0005] In order to achieve the above object, the basic scheme of the present invention is as follows: a pile driving method for quicksand strata, comprising the following steps:

[0006] Step 1: Determine the piling position by laying out the line and positioning, prepare the sleeve and the down-the-hole drill, and slide the sleeve and the down-the-hole drill coaxially; use the down-the-hole drill to drill a hole at the piling position to form a piling hole; while the down-the-hole drill is drilling, the sleeve moves down along the piling hole synchronously;

[0007] Step 2: After the pile hole is drilled, the sleeve is moved to the bottom of the pile hole; prepare several steel pipes, lower the steel pipes into the sleeve, and the steel pipes are all fitted with the inner wall of the sleeve, and the adjacent two steel pipes are fitted in sequence; after the inner wall of the sleeve is covered by the steel pipes, the sleeve is pulled out vertically;

[0008] Step 3: Prepare the air compressor to remove the quicksand between the steel pipes;

[0009] Step 4: Prepare a small grouting pipe and several plugs. The side wall of the small grouting pipe is provided with several grouting holes. The plugs are clamped in the grouting holes at the upper end of the small grouting pipe. The lower end of the small grouting pipe is moved to the bottom of the pile hole. The lower end of the small grouting pipe is moved upward along the axial direction of the steel pipe. Grouting is sequentially performed on the steel pipe, the pile hole and the quicksand formation from bottom to top.

[0010] Step 5: Prepare a number of oblique steel pipe piles, insert them obliquely into the quicksand formation, and weld the upper ends of the oblique steel pipe piles to the upper ends of the steel pipes to form a pile base;

[0011] Step 6: Prepare a rotary drilling rig and several steel casings. The rotary drilling rig drills holes in the range between the several steel pipes to form steel casing installation holes. The steel casing installation holes are coaxial with the pile holes. After drilling one section, lower one section of steel casing. Repeat the drilling and lowering operations of the steel casing installation holes. When the lowest steel casing moves to the outside of the lower end of the steel pipe, stop the drilling and lowering operations of the steel casing installation holes.

[0012] Step 7: Prepare the steel cage, lower it into the steel casing, and pour concrete into the steel casing to form engineering piles.

[0013] The technical principle of the present invention is as follows: in step 2, a vertically arranged steel pipe is used, and in step 5, a plurality of inclined steel pipe piles are used to form a combination of straight piles and inclined piles. The steel pipe and the inclined steel pipe piles have a good wall protection effect; the inclined steel pipe piles play a role in resisting lateral thrust, avoiding the displacement or breakage of the engineering piles, and ensuring the quality of the engineering piles in step 7; at the same time, in step 5, the upper end of the steel pipe and the upper end of the inclined steel pipe pile are welded together to form a whole, so that the steel pipe and the inclined steel pipe piles have strong stability.

[0014] In step 4, the small grouting pipe cooperates with the plug to carry out grouting from the bottom of the pile hole from bottom to top, ensuring the grouting effect at the bottom of the pile hole and preparing stability for the subsequent installation of the steel casing and the forming of the engineering pile; in step 7, under the protection of the steel casing and steel pipe, the collapse of the hole and the deviation of the hole are avoided, and the engineering pile is not prone to tilting or even breaking during the construction process.

[0015] Furthermore, the oblique steel pipe piles are evenly arranged obliquely around the circumference of the steel pipe, and the upper ends of the oblique steel pipe piles are located between two adjacent steel pipes. There is only one oblique steel pipe pile between the two adjacent steel pipes.

[0016] Through the above arrangement, the inclined steel pipe piles and the steel pipes are evenly arranged around the piling position, and the inclined steel pipe piles and the steel pipes can evenly support the mud and sand around the engineering piles, reducing the lateral force of the mud and sand on the engineering piles.

[0017] Furthermore, the lower end surface of the inclined steel pipe pile and the lower end surface of the steel pipe are located on the same horizontal plane.

[0018] Through the above arrangement, the oblique steel pipe pile and the lower end of the steel pipe can act synchronously, opposite to the lower end of the engineering pile, to achieve stable support for the engineering pile.

[0019] Furthermore, the angle between the axis of the inclined steel pipe pile and the axis of the steel pipe is 8-20°.

[0020] Through the above arrangement, the horizontal distance between the lower end of the inclined steel pipe pile and the lower end of the steel pipe will not be too far, so that the lower end of the inclined steel pipe pile can stably provide support for the sand layer at the lower end of the steel pipe.

[0021] Furthermore, in step 5, an I-beam is welded between the upper end of the inclined steel pipe pile and the upper end of the steel pipe, and both sides of the I-beam web are respectively fitted and welded to the side walls of the inclined steel pipe pile and the steel pipe, and the side walls of the I-beam flange are respectively fitted and welded to the side walls of the inclined steel pipe pile and the steel pipe.

[0022] Through the above arrangement, the I-beam can improve the fit between the side walls of the inclined steel pipe pile and the side walls of the steel pipe, and improve the welding strength between the inclined steel pipe pile and the steel pipe.

[0023] Further, the lower end of the steel casing is lower than the lower end of the steel pipe.

[0024] Through the above-mentioned setting, the steel casing can better expand the installation depth of the engineering pile and improve the setting strength of the engineering pile.

[0025] Furthermore, the outer diameters of the inclined steel pipe piles and the steel pipes are both 200-170 mm.

[0026] Through the above arrangement, the specifications of the inclined steel pipe pile and the steel pipe are consistent, which facilitates the splicing and welding of the upper ends of the inclined steel pipe pile and the steel pipe.

[0027] Furthermore, the outer diameter of the steel casing is 0.9-1.1 m.

[0028] Through the above arrangement, the outer diameter of the steel casing matches the cylinder composed of several steel pipes, which makes it easier for the steel casing to stably support the engineering piles.

[0029] Furthermore, the inner diameter of the steel casing is 0.8-0.9 m.

[0030] Through the above arrangement, the inner diameter of the steel casing matches the engineering pile to form an engineering pile of corresponding diameter, which facilitates the shaping of the engineering pile.

[0031] Furthermore, the diameter of the cylindrical cross section formed by the centers of the cross sections of the plurality of steel pipes is 1.2-1.3 m.

[0032] Through the above arrangement, the cylindrical cross-sectional profile formed by the plurality of steel pipes cooperates with the steel casing, so that the steel pipes fit outside the steel casing and support the steel casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a construction flow chart of a piling method for quicksand formations according to an embodiment of the present invention.

[0034] Figure 2 This is a cross-sectional view of the structure after the pile foundation construction is completed in an embodiment of the present invention.

[0035] Figure 3 for Figure 2 Top view of the pile foundation structure.

[0036] Figure 4 This is a structural diagram of the welding point between the steel pipe and the inclined steel pipe pile.

[0037] In the above drawings: steel pipe 10 , inclined steel pipe pile 20 , I-beam 30 , first weld 301 , second weld 302 , steel casing 40 , engineering pile 50 . DETAILED DESCRIPTION

[0038] The technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0039] This embodiment is basically as Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, the embodiment of the present invention provides a piling method for quicksand formation, which specifically includes the following steps:

[0040] Step 1: Determine the piling position by laying out the line and positioning, prepare the sleeve and the down-the-hole drill, and slide the sleeve and the down-the-hole drill coaxially; use the down-the-hole drill to drill a hole at the piling position to form a piling hole; while the down-the-hole drill is drilling, the sleeve moves down along the piling hole synchronously;

[0041] Step 2: After the pile hole is drilled, the sleeve moves to the bottom of the pile hole; prepare several steel pipes 10, such as Figure 2 As shown, the steel pipes 10 are lowered into the sleeve, and the steel pipes 10 are all fitted with the inner wall of the sleeve, and two adjacent steel pipes 10 are fitted in sequence. The diameter of the cylindrical cross section formed by the center of the cross section of the steel pipes 10 is 1.2m. After the inner wall of the sleeve is covered by the steel pipes 10, the sleeve is pulled out vertically.

[0042] Step 3: Prepare an air compressor to remove quicksand between the steel pipes 10;

[0043] Step 4: Prepare a small grouting pipe and several plugs. The side wall of the small grouting pipe is provided with several grouting holes. The plugs are clamped in the grouting holes at the upper end of the small grouting pipe. The lower end of the small grouting pipe is moved to the bottom of the pile hole. The lower end of the small grouting pipe is moved upward along the axial direction of the steel pipe 10. Grouting is sequentially performed on the steel pipe 10, the pile hole and the quicksand formation from bottom to top.

[0044] Step 5: Prepare several inclined steel pipe piles 20, the outer diameters of the inclined steel pipe piles 20 and the steel pipes 10 are both 180 mm; Figure 2 and Figure 3 As shown, several inclined steel pipe piles 20 are inserted obliquely and installed in the quicksand formation. The inclined steel pipe piles 20 are evenly arranged around the steel pipe 10 in the circumferential direction, and the upper ends of the inclined steel pipe piles 20 are located between two adjacent steel pipes 10. There is only one inclined steel pipe pile 20 between two adjacent steel pipes 10. The lower end surface of the inclined steel pipe pile 20 and the lower end surface of the steel pipe 10 are located on the same horizontal plane. The angle between the axis of the inclined steel pipe pile 20 and the axis of the steel pipe 10 is 10°. The upper end of the inclined steel pipe pile 20 is welded to the upper end of the steel pipe 10 to form a pile basic body. When welding, Figure 4 As shown, an I-beam 30 is welded between the upper end of the oblique steel pipe pile 20 and the upper end of the steel pipe 10. Both sides of the web of the I-beam 30 are respectively fitted and welded to the side walls of the oblique steel pipe pile 20 and the steel pipe 10 to form a first weld 301. The side walls of the flanges of the I-beam 30 are fitted and welded to the side walls of the oblique steel pipe pile 20 and the steel pipe 10 to form a second weld 302.

[0045] Step 6: Prepare a rotary drilling rig and several steel casings 40, the outer diameter of the steel casing 40 is 1m; the inner diameter of the steel casing 40 is 0.9m; the rotary drilling rig drills holes in the range between the several steel pipes 10 to form installation holes for the steel casing 40, and the installation holes for the steel casing 40 are coaxial with the pile hole; after drilling one section, lower a section of the steel casing 40; Figure 2 As shown, the drilling of the installation hole of the steel casing 40 and the lowering of the steel casing 40 are repeated. When the bottom steel casing 40 moves to the outside of the lower end of the steel pipe 10, the drilling of the installation hole of the steel casing 40 and the lowering of the steel casing 40 are stopped; the lower end of the steel casing 40 is lower than the lower end of the steel pipe 10;

[0046] Step 7: Prepare the steel cage, such as Figure 2 As shown, the steel cage is lowered into the steel casing 40 , and concrete is poured into the steel casing 40 to form an engineering pile 50 .

[0047] In the above construction process, miniature steel pipes 10 and oblique steel pipe piles 20 are used to form a combination of straight piles and oblique piles. The steel pipes 10 have the function of protecting the wall, and the oblique steel pipe piles 20 have the function of resisting lateral thrust, thereby preventing the engineering piles 50 from being offset or broken, and ensuring the quality of the engineering piles 50. At the same time, in step 5, the upper end of the steel pipe 10 and the upper end of the oblique steel pipe pile 20 are welded together to form a whole, so that the steel pipe 10 and the oblique steel pipe pile 20 have strong stability.

[0048] In step 4, the small grouting pipe cooperates with the plug to perform grouting from the bottom of the pile hole from bottom to top, ensuring the grouting effect at the bottom of the pile hole and preparing stability for the subsequent installation of the steel casing 40 and the forming of the engineering pile 50; in step 7, under the protection of the steel casing 40 and the steel pipe 10, the collapse of the hole and the deviation of the hole are avoided, which can effectively avoid the economic loss of rework caused by the collapse of the hole and the deviation of the hole, and also improve the quality of the engineering pile 50.

[0049] In this process, compared with the existing construction method, the amount of concrete used in the grouting process is also reduced, which can reduce the construction cost of this part.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A piling method for quicksand strata, characterized in that: The following steps are involved: Step 1: Determine the piling position by laying out the line and positioning, prepare the sleeve and the down-the-hole drill, and slide the sleeve and the down-the-hole drill coaxially; use the down-the-hole drill to drill a hole at the piling position to form a piling hole; while the down-the-hole drill is drilling, the sleeve moves down along the piling hole synchronously; Step 2: After the pile hole is drilled, the sleeve is moved to the bottom of the pile hole; prepare several steel pipes, lower the steel pipes into the sleeve, and the steel pipes are all fitted with the inner wall of the sleeve, and the adjacent two steel pipes are fitted in sequence; after the inner wall of the sleeve is covered by the steel pipes, the sleeve is pulled out vertically; Step 3: Prepare the air compressor to remove the quicksand between the steel pipes; Step 4: Prepare a small grouting pipe and several plugs. The side wall of the small grouting pipe is provided with several grouting holes. The plugs are clamped in the grouting holes at the upper end of the small grouting pipe. The lower end of the small grouting pipe is moved to the bottom of the pile hole. The lower end of the small grouting pipe is moved upward along the axial direction of the steel pipe. Grouting is sequentially performed on the steel pipe, the pile hole and the quicksand formation from bottom to top. Step 5: prepare a number of oblique steel pipe piles, which are obliquely inserted and installed into the quicksand stratum. The oblique steel pipe piles are evenly arranged obliquely around the circumference of the steel pipe, and the upper ends of the oblique steel pipe piles are located between two adjacent steel pipes. There is one and only one oblique steel pipe pile between the two adjacent steel pipes. The upper ends of the oblique steel pipe piles are welded to the upper ends of the steel pipes to form a pile basic body. The lower end faces of the oblique steel pipe piles and the lower end faces of the steel pipes are located on the same horizontal plane, and the angle between the axis of the oblique steel pipe piles and the axis of the steel pipes is 8-20°. During welding, an I-beam is welded between the upper ends of the oblique steel pipe piles and the upper ends of the steel pipes. Both sides of the I-beam web are respectively fitted and welded to the side walls of the oblique steel pipe piles and the steel pipes to form a first weld. The side walls of the flanges of the I-beams are fitted and welded to the side walls of the oblique steel pipe piles and the steel pipes to form a second weld. Step 6: Prepare a rotary drilling rig and several steel casings. The rotary drilling rig drills holes in the range between several steel pipes to form steel casing installation holes. The steel casing installation holes are coaxial with the pile holes. After drilling one section, lower one section of steel casing. Repeat the steel casing installation hole drilling and steel casing lowering operations. When the lowest steel casing moves to the outside of the lower end of the steel pipe, stop the steel casing installation hole drilling and steel casing lowering operations. The lower end of the steel casing is lower than the lower end of the steel pipe. Step 7: Prepare the steel cage, lower it into the steel casing, and pour concrete into the steel casing to form engineering piles.

2. A piling method for quicksand strata according to claim 1, characterized in that: The outer diameters of the inclined steel pipe piles and the steel pipes are both 200-170 mm.

3. A piling method for quicksand strata according to claim 2, characterized in that: The outer diameter of the steel casing is 0.9-1.1m.

4. A piling method for quicksand strata according to claim 3, characterized in that: The inner diameter of the steel casing is 0.8-0.9m.

5. A piling method for quicksand strata according to claim 4, characterized in that: The diameter of the cylindrical cross section formed by the center of the cross sections of several steel pipes is 1.2-1.3m.

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