A partially recyclable interlocking pile support structure and construction method

Abstract

The present invention discloses a partially recyclable interlocking pile support structure and a construction method, wherein the interlocking pile support structure comprises a plurality of steel pipe piles and a plurality of medium-fine sand plain concrete thin-walled pipe piles; the centers of the plurality of steel pipe piles and the plurality of medium-fine sand plain concrete thin-walled pipe piles are located on the same straight line; a gap is left between two adjacent medium-fine sand plain concrete thin-walled pipe piles, which are respectively interlocked with the same steel pipe pile; the pile ends of the medium-fine sand plain concrete thin-walled pipe piles penetrate into the impermeable layer, and the length of the steel pipe piles is not less than that of the medium-fine sand plain concrete thin-walled pipe piles. Compared with the existing interlocking pile support structure, the present invention has a fast construction speed, the steel pipe piles can be recycled and reused, and the production cost is reduced. The support structure of the present invention has a good water-stopping effect and a large overall bending stiffness, and is particularly suitable for deep foundation pit support projects on soft soil foundations.

Description

Technical Field

[0001] The invention belongs to the technical field of interlocking piles, and in particular relates to a partially recyclable interlocking pile supporting structure and a construction method. Background Art

[0002] Interlocking piles are a kind of foundation pit retaining structure composed of a number of plain concrete piles and reinforced concrete piles arranged alternately in sequence. The plain concrete piles are composed of concrete, and the reinforced concrete piles are composed of steel bar skeleton and concrete. The adjacent plain concrete piles and reinforced concrete piles interlock with each other, thereby playing a role in retaining soil and stopping water.

[0003] The construction sequence of interlocking piles is to construct two plain concrete piles first, and then construct a reinforced concrete pile between the two already constructed plain concrete piles. When constructing reinforced concrete piles, the overlapping concrete parts of the two plain concrete piles and the reinforced concrete piles must be excavated in order to achieve the function of mutual interlocking. This objectively increases the amount of work and causes waste of concrete materials.

[0004] In addition, whether it is plain concrete piles or reinforced concrete piles, when constructing below the groundwater level or in soft soil or sandy soil layers, mud wall protection is required to prevent the hole wall from collapsing. Not only is the construction speed slow, but the mud is also difficult to handle later. Direct discharge without treatment will also pollute the environment. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a partially recyclable interlocking pile support structure and construction method which has a simple structure, is easy and quick to construct, has low cost, and does not require the concrete of the plain concrete pile to be excavated or the mud wall to be protected.

[0006] The technical solution adopted by the present invention is: a partially recyclable interlocking pile support structure, comprising a plurality of steel pipe piles and a plurality of medium-fine sand plain concrete thin-walled pipe piles; the centers of the plurality of steel pipe piles and the plurality of medium-fine sand plain concrete thin-walled pipe piles are located on the same straight line; a gap is left between two adjacent medium-fine sand plain concrete thin-walled pipe piles, which are respectively interlocked with the same steel pipe pile; the pile ends of the medium-fine sand plain concrete thin-walled pipe piles penetrate into the impermeable layer, and the length of the steel pipe pile is not less than that of the medium-fine sand plain concrete thin-walled pipe pile.

[0007] In the above-mentioned partially recyclable interlocking pile supporting structure, the outer diameter of the steel pipe pile is the same as the outer diameter of the medium-fine sand plain concrete thin-wall pipe pile.

[0008] A construction method for the above-mentioned partially recyclable interlocking pile support structure, the construction equipment of the medium-fine sand plain concrete thin-walled pipe pile includes a cylinder, two grouting pipes are symmetrically arranged on the inner wall of the cylinder, and the grouting pipes are arranged along the axis of the cylinder; an annular pipe is fixedly installed on the inner wall of the bottom of the cylinder, and the lower and upper sections of the annular pipe are wedge-shaped, which is convenient for sinking and pulling the cylinder; the outer wall of the annular pipe is a cylindrical surface, which is coaxial with the cylinder and has an outer diameter that is the same as the inner diameter of the cylinder; the cross-section of the annular pipe is an isosceles triangle, and the base of the isosceles triangle is the outer wall of the annular pipe; the grout outlet is arranged on the lower waist of the isosceles triangle;

[0009] The following steps are included

[0010] 1) Determine the grouting volume, grouting pressure and tube pulling speed through trial piles;

[0011] 2) Determine the pile position so that the pile driver and the construction equipment of medium-fine sand plain concrete thin-walled pipe piles are in place;

[0012] 2) Start the pile driver, vibrate and sink the cylinder to the designed depth, then inject cement mortar into one grouting pipe. The grouting pressure is the self-weight stress of the soil at the pile end. Wait until cement mortar flows out from the other grouting pipe. Then inject cement mortar into the two grouting hoses at the same time. The grouting pressure at this time is 5-10 times the self-weight stress of the soil at the pile end. Grouting takes 3-5 minutes. The cement mortar is diffused to the soil near the cylinder end through high-pressure penetration or splitting grouting to form an enlarged head reinforcement body.

[0013] 3) Use the pile driver to vibrate and pull out the cylinder, and grout according to the designed grouting pressure while pulling out the cylinder, keeping the grouting pressure and the speed of pulling out the cylinder unchanged;

[0014] 4) Move the machine to the next pile position and repeat steps 2)-3) to drive a thin-walled pipe pile made of medium-fine sand and plain concrete.

[0015] 5) At the pile position where two medium-fine sand plain concrete thin-walled pipe piles have been driven, hoist the large-diameter prefabricated steel pipe piles into place, start the pile driver's vibrating hammer, and sink the steel pipe piles to the designed depth;

[0016] 6) Repeat steps 4)-5) until all the medium-fine sand plain concrete thin-walled pipe piles and steel pipe piles are driven;

[0017] In the above-mentioned construction method of the partially recyclable interlocking pile supporting structure, a cover plate is provided on the top of the cylinder of the construction equipment.

[0018] In the construction method of the partially recyclable interlocking pile support structure, the sand in the cement mortar is medium-fine sand, and the cement is ordinary Portland cement with a PO 42.5 grade.

[0019] In the construction method of the partially recyclable interlocking pile support structure, before driving the steel pipe pile, an isolation agent or a release agent is applied to the inner and outer surfaces of the steel pipe pile.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The plain concrete of the thin-walled pipe piles of medium-fine sand plain concrete constructed first and the steel pipe piles constructed later does not need to be excavated, which is convenient for construction and improves the construction speed; and this part is beneficial to the bending stiffness of the interlocking pile support structure;

[0022] 2. The construction speed of the interlocking pile support structure of the present invention is fast. The average construction time of one pile is about 30 minutes, which is more than ten times the construction speed of conventional interlocking piles.

[0023] 3. The present invention does not require mud wall protection during piling, thus avoiding the later mud treatment and further improving the construction speed;

[0024] 4. The present invention adopts the pre-grouting technology to form the pile end enlarged head before pulling out the cylinder, and adopts the method of pulling out the cylinder and grouting at the same time to form the pile. The gap left by pulling out the cylinder will be quickly filled with grouting liquid in excess under the grouting pressure that exceeds the deadweight stress at that place by several times, so the pile quality is high;

[0025] 5. The steel pipe piles used in the present invention can be recycled and reused after the use of the occlusal piles is completed, and the medium-fine sand plain concrete thin-wall pipe piles use less concrete, thereby reducing the production cost.

[0026] 6. The snap pile produced by the present invention has large bending rigidity, strong anti-overturning ability, and good double-layer water-stopping effect. Compared with the snap piles of the prior art, the quality is more reliable and the safety and stability are good. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of the construction equipment of the medium-fine sand plain concrete thin-wall pipe pile of the present invention.

[0028] Figure 2 It is a top view of the construction equipment of the medium-fine sand plain concrete thin-wall pipe pile of the present invention.

[0029] Figure 3 It is a bottom view of the construction equipment of the medium-fine sand plain concrete thin-wall pipe pile of the present invention.

[0030] Figure 4 It is a top view of the partially recyclable snap pile support structure of the present invention.

[0031] Figure 5 yes Figure 4 Cross-sectional view of the inner wall AA of the foundation pit after excavation to elevation OO. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] like Figure 4-5 As shown, the partially recyclable interlocking pile support structure of the present invention comprises a plurality of steel pipe piles 7 and a plurality of medium-fine sand plain concrete thin-walled pipe piles 6; the outer diameter of the steel pipe piles 7 is the same as the outer diameter of the medium-fine sand plain concrete thin-walled pipe piles 6. The centers of the plurality of steel pipe piles 7 and the plurality of medium-fine sand plain concrete thin-walled pipe piles 6 are located on the same straight line; a gap is left between two adjacent medium-fine sand plain concrete thin-walled pipe piles 6, and each interlocks with the same steel pipe pile 7.

[0034] like Figure 1-3 As shown, the construction equipment of the medium-fine sand plain concrete thin-wall pipe pile 6 of the present invention includes a cylinder 4 and two grouting pipes 3. The diameter of the cylinder 4 is 1.0-4.0m, the length is 10.0-30.0m, and the material of the cylinder 4 is steel. A cover plate 2 is provided on the top of the cylinder, and the vibrating hammer 1 of the pile driver transmits the exciting force to the round steel cylinder 4 through the cover plate 2 to make it sink.

[0035] Two grouting pipes 3 are symmetrically welded on the inner wall of the cylinder 4, and the grouting pipes 3 are arranged along the axis of the cylinder. An annular pipe 5 is welded on the inner wall of the bottom of the cylinder 4, and the cross section of the annular pipe 5 is an isosceles triangle. The outer wall of the annular pipe is a cylindrical surface, and the base of the isosceles triangle is a cylindrical surface. The outer diameter of the annular pipe is the same as the inner diameter of the cylinder 4, and the annular pipe 5 is coaxial with the cylinder 4. The cross section of the annular pipe 5 is composed of two wedge-shaped structures, which are convenient for sinking and pulling the cylinder. Two slurry inlets are provided on the top of the annular pipe 5, which are respectively connected to the lower ends of the two grouting pipes 3; a plurality of slurry outlets in the shape of circular holes are opened on the lower waist of the isosceles triangle of the cross section of the annular pipe 5, and the slurry outlets and the slurry inlets are connected to each other through the annular pipe 5. The spacing between adjacent circular hole slurry outlets is 100-200mm; the diameter of the circular hole slurry outlet is 5-8mm. The height of the isosceles triangle of the cross section of the annular pipe 5 is 10.0~15.0cm.

[0036] The construction method of the partially recyclable occlusal pile support structure of the present invention comprises the following steps:

[0037] 1) Preparation: A. Apply an isolating agent or a release agent to the inner and outer surfaces of the steel pipe pile 6 to facilitate the recovery of the steel pipe pile 7. B. Determine the grouting volume, grouting pressure and tube pulling speed through trial piles. C. Determine the pile position so that the construction equipment of the pile driver and the medium-fine sand plain concrete thin-walled pipe pile 6 are in place.

[0038] 2) Start the vibrating hammer, vibrate and sink the cylinder 1 to the designed depth, then start to inject cement mortar into a grouting pipe 3, the grouting pressure is the self-weight stress of the soil at the pile end, wait until the cement mortar flows out from the other grouting pipe, and then inject cement mortar into the two grouting hoses at the same time; maintain a large grouting pressure for 3-5 minutes, the grouting pressure is 5-10 times the self-weight stress of the soil at the pile end, and let the cement slurry diffuse to the adjacent soil at the cylinder end through high-pressure penetration or splitting grouting to form an enlarged head reinforcement body; the sand in the cement mortar is medium-fine sand, and the cement is ordinary Portland cement with a PO 42.5 grade.

[0039] 3) Use the pile driver to vibrate and pull out the cylinder, and grout according to the designed grouting pressure while pulling out the cylinder, keeping the grouting pressure and the speed of pulling out the cylinder constant, until the medium-fine sand plain concrete thin-walled pipe pile is 60% completed;

[0040] 4) Move the machine to the next pile position and repeat steps 2)-3) to drive a medium fine sand plain concrete thin wall pipe pile 6.

[0041] 5) At the pile position where two medium-fine sand plain concrete thin-walled pipe piles 6 have been driven, a large-diameter prefabricated steel pipe pile 7 is hoisted into place, and the pile driver's vibrating hammer is started to sink the steel pipe pile 7 to the designed depth;

[0042] 6) Repeat steps 4)-5) until all the medium-fine sand plain concrete thin-walled pipe piles 6 and steel pipe piles 7 are driven.

Claims

1. A construction method for a partially recyclable interlocking pile support structure, wherein the partially recyclable interlocking pile support structure comprises a plurality of steel pipe piles and a plurality of medium-fine sand plain concrete thin-walled pipe piles; the centers of the plurality of steel pipe piles and the plurality of medium-fine sand plain concrete thin-walled pipe piles are located on the same straight line; a gap is left between two adjacent medium-fine sand plain concrete thin-walled pipe piles, which are respectively interlocked with the same steel pipe pile; the pile ends of the medium-fine sand plain concrete thin-walled pipe piles penetrate into the impermeable layer, and the length of the steel pipe pile is not less than that of the medium-fine sand plain concrete thin-walled pipe pile; The construction equipment of the medium-fine sand plain concrete thin-wall pipe pile includes a cylinder, and two grouting pipes are symmetrically arranged on the inner wall of the cylinder, and the grouting pipes are arranged along the axis of the cylinder; an annular pipe is fixedly installed on the inner wall of the bottom of the cylinder, and the lower and upper sections of the annular pipe are wedge-shaped, which is convenient for sinking and pulling the cylinder; the outer wall of the annular pipe is a cylindrical surface, which is coaxial with the cylinder and has an outer diameter that is the same as the inner diameter of the cylinder; the cross-section of the annular pipe is an isosceles triangle, and the base of the isosceles triangle is the outer wall of the annular pipe; a plurality of grouting outlets in the shape of circular holes are opened on the lower waist of the isosceles triangle of the cross-section of the annular pipe, and the grouting outlets are arranged on the lower waist of the isosceles triangle; The steps include: 1) Determine the grouting volume, grouting pressure and tube pulling speed through trial piles; 2) Determine the pile position so that the pile driver and the construction equipment of medium-fine sand plain concrete thin-walled pipe piles are in place; 2) Start the pile driver, vibrate and sink the cylinder to the designed depth, then inject cement mortar into one grouting pipe. The grouting pressure is the self-weight stress of the soil at the pile end. Wait until cement mortar flows out from the other grouting pipe. Then inject cement mortar into the two grouting hoses at the same time. The grouting pressure at this time is 5-10 times the self-weight stress of the soil at the pile end. Grouting takes 3-5 minutes. The cement mortar is diffused to the soil near the cylinder end through high-pressure penetration or splitting grouting to form an enlarged head reinforcement body. 3) Use the pile driver to vibrate and pull out the cylinder, and grout according to the designed grouting pressure while pulling out the cylinder, keeping the grouting pressure and the speed of pulling out the cylinder unchanged; 4) Move the machine to the next pile position and repeat steps 2)-3) to drive a thin-walled pipe pile made of medium-fine sand and plain concrete. 5) At the pile position where two medium-fine sand plain concrete thin-walled pipe piles have been driven, hoist the steel pipe pile into place, start the pile driver's vibrating hammer, and sink the steel pipe pile to the designed depth; 6) Repeat steps 4)-5) until all the medium-fine sand plain concrete thin-wall pipe piles and steel pipe piles are driven to form an interlocking pile wall support structure.

2. The construction method of the partially recyclable occlusal pile support structure according to claim 1 is characterized by: A cover plate is provided on the top of the cylinder of the construction equipment.

3. The construction method of the partially recyclable occlusal pile support structure according to claim 1 is characterized by: The sand in the cement mortar is medium-fine sand, and the cement is ordinary Portland cement with a PO 42.5 mark.

4. The construction method of the partially recyclable occlusal pile support structure according to claim 1 is characterized by: Before driving steel pipe piles, apply isolation agent or release agent on the inner and outer surfaces of the steel pipe piles.

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