A rotary drilling and deep mixing large diameter rigid composite pile structure and its construction method

Abstract

The present invention discloses a rotary drilling and deep mixing large-diameter rigid composite pile structure and a construction method thereof, comprising a foundation and a foundation pit support mechanism arranged on the foundation; the foundation pit support mechanism is composed of a plurality of composite piles, the composite piles comprising cement-soil mixing piles, the cement-soil mixing piles being embedded in the top surface of the foundation; the cement-soil mixing piles are arranged longitudinally; the peripheral walls of the cement-soil mixing piles are embedded in the foundation; a prefabricated pile group is arranged in the cement-soil mixing piles; the prefabricated pile group coincides with the axial direction of the cement-soil mixing piles; the bearing capacity of the foundation or the water-stopping and supporting effect of the foundation pit can be improved, and the safety of the upper structure or foundation pit support can be ensured; the present invention has high construction efficiency and cost savings, can maximize the potential of the original soil, can solve the cement-mixing pile construction problem of deep gravel and crushed stone soil layers, and is a rotary drilling and deep mixing large-diameter rigid composite pile structure and a construction method thereof with high bearing capacity.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, and in particular to a rotary drilling and deep mixing large-diameter rigid composite pile structure and a construction method thereof. Background Art

[0002] With the rapid development of my country's industrial construction and civil fields, the number of floors and height of buildings are getting higher and higher. Therefore, the requirements for the bearing capacity of the foundation and the support of the foundation pit are getting higher and higher. In order to meet the requirements of the design of housing exhibitions, people have developed more composite pile foundations, and the rigid composite pile is a new type of composite pile foundation that is widely accepted and developed rapidly.

[0003] In order to meet the needs of different soil layers, especially alluvial, lacustrine, slope residual and other foundation soils, it is urgent to invent a rotary drilling and deep mixing large-diameter rigid composite pile structure to meet the needs of bearing capacity and deformation. Summary of the invention

[0004] The purpose of the invention is to provide a rotary drilling and deep mixing large-diameter strong composite pile structure and a construction method thereof.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention provides a rotary drilling and deep mixing large-diameter rigid composite pile structure, comprising a foundation and a foundation pit support mechanism arranged on the foundation; the foundation pit support mechanism is composed of a plurality of the composite piles, the composite piles comprising cement-soil mixing piles, the cement-soil mixing piles being embedded in the top surface of the foundation; the cement-soil mixing piles are arranged longitudinally; the peripheral wall of the cement-soil mixing piles is embedded in the foundation; a prefabricated pile group is arranged in the cement-soil mixing pile; the axial direction of the prefabricated pile group coincides with that of the cement-soil mixing pile.

[0006] Preferably, the diameter of the cement soil mixing pile is 800mm-1500mm; the length of the cement soil mixing pile is 10m-30m.

[0007] Preferably, the precast pile group includes at least one precast pile.

[0008] Preferably, two adjacent cement-soil mixing piles of the plurality of cement-soil mixing piles are interlocked with each other.

[0009] Preferably, the cross section of the precast pile is circular or square; the diameter or side length of the precast pile is 400mm-1000mm.

[0010] A method for constructing a rotary-drilled, deep-mixed, large-diameter rigid composite pile comprises the following steps:

[0011] Level the construction site and clear obstacles at the construction site;

[0012] Before excavation, measurement and layout shall be carried out to ensure that the construction site is well connected, leveled and leveled;

[0013] Excavating the construction site to the construction elevation;

[0014] After the pile position is staked out on the construction site, the mixer is put in place;

[0015] Using the mixer to perform forward and reverse mixing at the pile position, and adding a curing agent into the cement to construct the cement-soil mixing pile;

[0016] Repeat the above steps to sequentially complete a plurality of cement-soil mixing piles located in the same straight line direction;

[0017] After the construction of the cement-soil mixing pile is completed, the pile driver presses the prefabricated pile into the cement-soil mixing pile.

[0018] Preferably, the mixer is a high-torque mixer with an improved and lengthened drill rod.

[0019] Preferably, during the construction of the cement-soil mixing piles, different admixtures are added to the curing agent for various poor foundation soils.

[0020] Preferably, when the pile driver presses the precast pile, the precast pile is pressed into the center of the cement-soil mixing pile by static pressure or vibration according to different soil layers.

[0021] The present invention discloses the following technical effects: the present invention provides a rotary drilling and deep mixing large-diameter rigid composite pile structure and a construction method thereof, which improves the bearing capacity of the foundation or the water-stopping and supporting effect of the foundation pit, and ensures the safety of the upper structure or the foundation pit support. The present invention has high construction efficiency and cost savings, can maximize the potential of the original soil, can solve the problem of cement mixing pile formation in deep round gravel and crushed stone soil layers, reduces environmental pollution, and has the characteristic of little disturbance to surrounding existing buildings. The present invention is a rotary drilling and deep mixing large-diameter rigid composite pile structure with high bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a structural schematic diagram of the foundation pit supporting structure of the present invention;

[0024] Figure 2 A top view of the prefabricated piles of the present invention arranged continuously;

[0025] Figure 3A top view of the prefabricated pile spacing arrangement of the present invention;

[0026] Figure 4 A rotary drilling machine according to the present invention;

[0027] Figure 5 A pile driver according to the present invention;

[0028] Figure 6 This is a structural schematic diagram of a cement-soil mixing pile of the present invention;

[0029] Figure 7 It is a structural schematic diagram of a single pile cap in Example 4 of the present invention;

[0030] Figure 8 It is a structural schematic diagram of a double pile cap in Example 4 of the present invention;

[0031] Fig. 9 It is a structural schematic diagram of a three-pile cap in Example 4 of the present invention;

[0032] Fig.10 It is a structural schematic diagram of a four-pile cap in Example 4 of the present invention;

[0033] Fig.11 It is a structural schematic diagram of a five-pile cap in Example 4 of the present invention;

[0034] Fig.12 This is a schematic diagram of the structure of a full-floor pile cap in Example 4 of the present invention;

[0035] Fig.13 This is a schematic diagram of the structure of the connecting mechanism in Example 2 of the present invention;

[0036] Fig.14 This is a schematic diagram of the structure of the prefabricated pile connection in Example 3 of the present invention;

[0037] Fig.15 It is a partial enlarged view of A1 in Example 3 of the present invention;

[0038] Fig.16 It is a partial enlarged view of A2 in Example 3 of the present invention;

[0039] Fig.17 It is a partial enlarged view of A3 in Example 3 of the present invention;

[0040] Fig.18 It is a partial enlarged view of A4 in Example 2 of the present invention;

[0041] Among them, 1-cement soil mixing pile, 2-precast pile, 3-connecting tube, 4-insertion tube, 5-cap, 6-cushion, 7-insertion rod, 8-clamping block, 9-clamping groove, 10-spring, 11-power rod, 12-connecting rod. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] Reference Figure 1-6 A rotary excavation and deep mixing large diameter rigid composite pile structure, comprising a foundation and a foundation pit support mechanism arranged on the foundation; the foundation pit support mechanism is composed of a plurality of composite piles, the composite piles comprising a cement soil mixing pile 1, the cement soil mixing pile 1 is embedded in the top surface of the foundation; the cement soil mixing pile 1 is arranged longitudinally; the surrounding wall of the cement soil mixing pile 1 is embedded in the foundation; a prefabricated pile group is arranged in the cement soil mixing pile 1; the axial direction of the prefabricated pile group coincides with that of the cement soil mixing pile 1. The cement soil mixing pile 1 is a rotary excavation and mixing large diameter cement soil mixing pile, which can be applied to pile foundation engineering and foundation pit engineering in combination with the prefabricated pile 2.

[0046] According to a further optimization scheme, the diameter of the cement-soil mixing pile 1 is 800mm-1500mm; the length of the cement-soil mixing pile 1 is 10m-30m. The prefabricated piles 2 can also be arranged at intervals in a plurality of the cement-soil mixing piles 1; increasing the diameter of the cement-soil mixing pile 1 can increase the lateral friction resistance of the cement-soil mixing pile 1 and increase the bearing capacity of the composite pile foundation.

[0047] In a further optimized solution, the precast pile group includes at least one precast pile 2. The precast piles 2 are arranged in a special plane, and when there are more than one precast pile 2, the precast piles 2 are sequentially inserted into the cement-soil mixing pile 1 and connected end to end.

[0048] Further optimization scheme, the adjacent two cement soil mixing piles 1 of the plurality of cement soil mixing piles 1 are interlocked with each other. The cement soil mixing piles 1 with large diameters are interlocked with each other to form a water-stopping structure, and then the prefabricated piles 2 are inserted continuously or at intervals in the middle to form an interlocking pile continuous wall structure integrating water-stopping and support. This structure can solve the problem of water-stop curtain construction in deep round gravel and crushed stone soil layers, reduce environmental pollution, and have little impact on surrounding existing buildings; the time interval for the construction of adjacent interlocking piles is determined according to field tests, and the large-diameter cement soil mixing piles 1 are interlocked with each other to increase the structural integrity and horizontal anti-lateral displacement stiffness.

[0049] Further optimization scheme, the cross section of the precast pile 2 is circular or square; the pile diameter or side length of the precast pile 2 is 400mm-1000mm. The pile diameter of the precast pile 2 should be smaller than the pile diameter of the cement soil mixing pile 1. According to the specific foundation soil conditions of the construction site, the total length of the precast pile 2 after connection can be less than, equal to or greater than the pile length of the cement soil mixing pile 1. The large-diameter cement soil mixing pile 1 can provide greater pile side friction resistance, saving costs compared with other pile types under the same bearing capacity requirements.

[0050] A method for constructing a rotary-drilled, deep-mixed, large-diameter rigid composite pile comprises the following steps:

[0051] Level the construction site and clear obstacles at the construction site;

[0052] Before excavation, measurement and layout shall be carried out to ensure that the construction site is well connected, leveled and leveled;

[0053] Excavating the construction site to the construction elevation;

[0054] After the pile position is staked out on the construction site, the mixer is put in place;

[0055] Use the mixer to perform forward and reverse mixing at the pile position, and add a curing agent into the cement to construct the cement-soil mixing pile 1;

[0056] Repeat the above steps to sequentially complete a plurality of cement-soil mixing piles 1 located in the same straight line direction;

[0057] After the construction of the cement-soil mixing pile 1 is completed, the pile driver presses the prefabricated pile 2 into the cement-soil mixing pile 1 .

[0058] To further optimize the plan, "three connections and one leveling" means that the construction site should have conditions such as water access, electricity access, road access and a level site.

[0059] According to a further optimization scheme, the prefabricated pile 2 is pressed into the center position of the cement-soil mixing pile 1 using the pile driver, and together with the cement-soil mixing pile 1, a rigid composite pile foundation is formed. The improved rotary drilling and mixing process can increase the diameter of the cement-soil mixing pile 1 and improve the pile quality, thereby increasing the bearing capacity of the composite pile foundation; in foundation pit support engineering, the water stopping and support problems in deep round gravel layers and crushed stone soil layers can be solved at the same time.

[0060] A further optimization scheme is that the mixer is a high-torque mixer with an improved and lengthened drill rod; the use of a high-torque mixer with an improved and lengthened drill rod can increase the pile diameter and pile length of the cement-soil mixing pile 1; this method breaks through the applicable stratum limit of conventional mixing piles and is suitable for foundations with all soil conditions except bedrock, including soft soil foundations, clay soil foundations, gravel soil foundations, sandy soil foundations and other special soil foundations; this method uses a forward and reverse mixing process to make the mixing of cement soil more uniform, and the quality of the pile is guaranteed.

[0061] According to a further optimization scheme, during the construction of the cement-soil mixing pile 1, different admixtures are added to the curing agent for various poor foundation soils; different admixtures can be added to the curing agent for various poor foundation soils to ensure the quality of the piles. During specific construction, different curing agents can be combined or used separately according to different soil layers.

[0062] Further optimization scheme, when the pile driver presses the precast pile 2, the precast pile 2 is pressed into the center of the cement soil mixing pile 1 by static pressure or vibration according to different soil layers. The pile driver presses the precast pile into the cement soil mixing pile 1 by static pressure or vibration according to different soil layers, so that it becomes a strong composite pile with good side friction resistance and stiffness; the pile diameter and pile length of the precast pile 2 should be smaller than the cement soil mixing pile; from the start of the construction of the precast pile 2 to the completion of the construction of the precast pile 2, the time should be controlled to be completed before the final setting of the cement soil mixing pile 1.

[0063] Example 2

[0064] Reference Fig.13 and Fig.18 , a connecting mechanism is provided in the prefabricated pile;

[0065] The connecting mechanism comprises a connecting tube 3; the connecting tube 3 is arranged in the inner cavity of the precast pile 2; the connecting tube 3 coincides with the axis of the precast pile 2; a plurality of plug-in tubes 4 are circumferentially arranged in the middle of the outer wall of the connecting tube 3; one end of the plug-in tube 4 is communicated with the outer wall of the connecting tube 3; the other end of the plug-in tube 4 is communicated with the inner wall of the precast pile 2; a power rod 11 is slidably connected to the top of the inner wall of the connecting tube 3; the top surface of the power rod 11 and the top surface of the connecting tube 3 are located in the same plane; the bottom surface of the power rod 11 is a conical structure; a connecting rod 12 is arranged at the bottom of the inner wall of the connecting tube 3; the top of the outer wall of the connecting rod 12 is fixedly connected to the bottom of the inner wall of the connecting tube 3; the bottom of the connecting rod 12 extends out of the inner cavity of the connecting tube 3; a clamping assembly is arranged at the bottom of the outer wall of the connecting rod 12; a plug-in rod 7 is arranged in the plug-in tube 4; the plug-in rod The end face of one end 7 close to the connecting tube 3 is an inclined surface; the inclined surface is adapted to the shape of the bottom surface of the power rod 11; when the precast pile is pressed into the cement-soil mixing pile 1 by the pile driver, the connecting rod 12 located at the bottom of the precast pile 2 is inserted into the top of the inner cavity of the precast pile 2 and abuts against the top surface of the power rod 11. When the precast pile 2 moves downward, the connecting rod 12 pushes the power rod 11 downward, and the bottom surface of the power rod 11 slides with the side of the plug-in rod 7, and pushes the plug-in rod 7 outward during the downward movement, so that the plug-in rod 7 extends out of the precast pile 2 and is inserted into the cement-soil mixing pile 1, thereby enhancing the connection strength between the precast pile 2 and the cement-soil mixing pile 1; after all the precast piles 2 are driven into the cement-soil mixing pile 1, concrete is poured into the precast pile 2 to enhance the strength of the precast pile 2.

[0066] Example 3

[0067] Reference Figure 14-17 The clamping assembly includes a clamping block 8; a plurality of clamping grooves 9 are circumferentially opened at the top of the inner wall of the connecting tube 3; a plurality of telescopic grooves are circumferentially opened at the bottom of the outer wall of the connecting rod 12; a spring 10 is fixedly connected to the bottom of the telescopic groove; the spring 10 is fixedly connected to the clamping block 8; the clamping block 8 is adapted to the clamping groove 9; after the clamping block 8 is extended into the clamping groove 9, the top and bottom surfaces of the two adjacent precast piles 2 are abutted to complete the connection, thereby enhancing the connectivity between the adjacent precast piles 2.

[0068] Example 4

[0069] Reference Figure 7-12The top surface of the foundation is provided with a cushion layer 6; the bottom surface of the cushion side is fixedly connected with a cap 5; the cushion layer 6 is adapted to the shape of the cap 5; the bottom surface of the cushion layer 6 is fixedly connected to the top surface of the cement-soil mixing pile 1; the cap 5 can be limited to a specific shape according to the number and arrangement position of the composite piles arranged on the bottom surface of the cap 5; the cap 5 can be divided into a single-pile cap, a double-pile cap, a three-pile cap, a four-pile cap, a five-pile cap and a full-pile cap.

[0070] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0071] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A rotary drilling and deep mixing large diameter rigid composite pile structure, comprising a foundation and a foundation pit support mechanism arranged on the foundation; the foundation pit support mechanism is composed of a plurality of the composite piles, characterized in that: The composite pile comprises a cement-soil mixing pile (1), wherein the cement-soil mixing pile (1) is embedded in the top surface of the foundation; the cement-soil mixing pile (1) is arranged longitudinally; the peripheral wall of the cement-soil mixing pile (1) is embedded in the foundation; a prefabricated pile group is arranged in the cement-soil mixing pile (1); the axial direction of the prefabricated pile group coincides with that of the cement-soil mixing pile (1); The prefabricated pile group comprises at least one prefabricated pile (2); The prefabricated pile (2) is provided with a connection mechanism, which comprises a connection tube (3), which is arranged in the inner cavity of the prefabricated pile (2); the connection tube (3) coincides with the axis of the prefabricated pile (2); a plurality of plug-in tubes (4) are circumferentially arranged in the middle of the outer wall of the connection tube (3); one end of the plug-in tube (4) is connected to the outer wall of the connection tube (3); the other end of the plug-in tube (4) is connected to the inner wall of the prefabricated pile (2); a power rod (11) is slidably connected to the top of the inner wall of the connection tube (3), and the top surface of the power rod (11) is connected to the connection tube The top surfaces of the connecting rod (3) are located on the same plane; the bottom surface of the power rod (11) is a conical structure; a connecting rod (12) is provided at the bottom of the inner wall of the connecting tube (3); the top of the outer wall of the connecting rod (12) is fixedly connected to the bottom of the inner wall of the connecting tube (3); the bottom of the connecting rod (12) extends out of the inner cavity of the connecting tube (3); a clamping assembly is provided at the bottom of the outer wall of the connecting rod (12); a plug-in rod (7) is provided in the plug-in tube (4); the end surface of the plug-in rod (7) close to the connecting tube (3) is an inclined surface, and the inclined surface is adapted to the shape of the bottom surface of the power rod (11).

2. A rotary drilling and deep mixing large diameter rigid composite pile structure according to claim 1, characterized in that: The diameter of the cement-soil mixing pile (1) is 800 mm-1500 mm; the length of the cement-soil mixing pile (1) is 10 m-30 m.

3. The rotary drilling and deep mixing large diameter rigid composite pile structure according to claim 1, characterized in that: Two adjacent cement-soil mixing piles (1) of the plurality of cement-soil mixing piles (1) are engaged with each other.

4. The rotary drilling and deep mixing large diameter rigid composite pile structure according to claim 1, characterized in that: The cross section of the prefabricated pile (2) is circular or square; the pile diameter or side length of the prefabricated pile (2) is 400mm-1000mm.

5. A method for constructing a rotary excavation and deep mixing large diameter rigid composite pile, based on a rotary excavation and deep mixing large diameter rigid composite pile structure according to any one of claims 1 to 4, characterized in that: The steps include: Level the construction site and clear obstacles at the construction site; Before excavation, measurement and layout shall be carried out to ensure that the construction site is well connected, leveled and leveled; Excavating the construction site to the construction elevation; After the pile position is staked out on the construction site, the mixer is put in place; Using the mixer to perform forward and reverse mixing at the pile position, and adding a curing agent into the cement, to construct the cement-soil mixing pile (1); Repeat the above steps to sequentially complete a plurality of cement-soil mixing piles (1) located in the same straight line direction; After the construction of the cement-soil mixing pile (1) is completed, the pile driver presses the prefabricated pile (2) into the cement-soil mixing pile (1).

6. A method for constructing large-diameter rigid composite piles by deep-drilling and mixing according to claim 5, characterized in that: The mixer is a high-torque mixer with an improved and lengthened drill rod.

7. The method for constructing large-diameter rigid composite piles by deep-drilling and mixing according to claim 5, characterized in that: During the construction of the cement soil mixing pile (1), different admixtures are added to the curing agent for various poor foundation soils.

8. The method for constructing large-diameter rigid composite piles by deep-drilling and mixing according to claim 5, characterized in that: When the pile driver presses the precast pile (2), the precast pile (2) is pressed into the center of the cement-soil mixing pile (1) by static pressure or vibration according to different soil layers.

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