Patent Application
20250146242
This patent application claims the benefit and priority of Chinese Patent Application No. 202311465995.4, filed with the China National Intellectual Property Administration on Nov. 7, 2023, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.
The present disclosure belongs to the technical field of pile foundation, and in particular to a T-shaped reamed pile, a composite foundation, and a construction method for the composite foundation.
With the acceleration of infrastructure construction and the increasing scale of construction in China, pile foundation is widely used in foundation projects in various fields due to its excellent engineering performance.
The traditional pile foundation usually adopts precast piles, which can be precast in the construction site or factory, and then transported to the pile location, and then disposed in place by hammering, vibration, and other means. Such pile sinking processes often cause damage to the pile body, leading to pile breakage at the joint, and lacking sufficient safety and reliability. As a soil compaction pile, the precast pile will disturb the surrounding soil, leading to problems such as floating, deviation and warping of the pressed pile. Secondly, due to the limitation of construction equipment, the precast pile cannot pass through the hard sandwiched layer, which often makes the pile length too short and the bearing stratum not ideal.
In addition, the cast-in-place concrete pile is also a common pile-forming method in engineering practice, but the cast-in-place concrete pile needs some time to set and harden, and due to the limitation of the construction conditions on site, the overall production time of the pile body is longer, which is not suitable for assembly line construction, leading to an increase in production cost.
With the continuous progress of China on high-quality development path, more stringent requirements are put forward for pile foundation in terms of bearing capacity and seismic performance, and the traditional pile foundation cannot be applied to collapsible filled ground, soft soil foundation and other soft foundations due to its defects in construction technology and bearing performance.
Therefore, there is a need to provide an improvement technical solution for the disadvantages in the prior art.
An objective of the present disclosure is to provide a T-shaped reamed pile, a composite foundation, and a construction method for the composite foundation, thus solving the problem that a precast pile is hard to sink, may disturb surrounding soil and cannot pass through a hard sandwiched layer.
To achieve the objective above, the present disclosure employs the following technical solution:
A T-shaped reamed pile is composed of a core pile, and a reamed body surrounding the outside of the core pile. A depth of the core pile is not lower than that of the reamed body. The reamed body includes an upper reamed body, and a lower reamed body; and a diameter of the upper reamed body is larger than that of the lower reamed body.
Preferably, the core pile is a precast pile, and the reamed body is a cast-in-place reamed body.
Preferably, the diameter of the upper reamed body is 1.5-2.5 times an outer diameter of the core pile, and a length of the upper reamed body is 5-10 times the outer diameter of the core pile.
Preferably, the length of the upper reamed body is not less than 2 m.
Preferably, a material of the reamed body is selected from fine aggregate concrete, a cement-soil mixture, or a cement-bentonite slurry. The core pile is selected from a prestressed concrete thin-walled pipe pile, a prestressed concrete square pile, a hollow square pile, or a prestressed concrete variable diameter pipe pile.
The present disclosure further provides a composite foundation. The composite foundation is composed of a T-shaped reamed pile, soil between piles, and a cushion layer. The T-shaped reamed pile is any of the T-shaped reamed piles.
Preferably, the cushion layer is a sand-gravel cushion layer, or a reinforced cement-soil cushion layer. The cushion layer has a thickness of 300-500 mm.
Preferably, the cushion layer is a reinforced cement-soil cushion layer, a reinforced material of the cushion layer is a double-layer steel plate mesh structure, and a thickness of a protective layer is not less than 80 mm.
The present disclosure further provides a construction method for a composite foundation, including the following steps:
Preferably, when the cushion layer is a reinforced cement-soil cushion layer, the cement soil is constructed by a compaction method, and a compressive strength is not less than 3 MPa.
Compared with the prior art, the present disclosure has beneficial effects as follows:
(1) The problem that the precast pile is hard to pass through the hard soil layer is solved. When design conditions are the same as conditions of construction equipment, a final pressure value of pile driving pressure can be reduced by 30%-60%, and the number of hammerings can be reduced by 50%-90%. The decrease of the pile driving pressure or the number of hammerings can reduce the damage to the precast pile, and the bearing capacity of a pile body of the precast pile is relatively improved. Meanwhile, the bearing capacity of the precast pile is also improved by the reamed body.
(2) The upper reamed body increases the horizontal resistance of the pile, reduces a horizontal displacement of a pile foundation under an earthquake load or other horizontal loads, and improves the seismic performance of the pile foundation.
(3) When the bearing stratum of the foundation is soft soil and a design spacing of the precast piles is the same, the load bearing of the pile can be effectively increased by increasing the diameter of the upper reamed body, thus reducing the load acting on the soil between piles, eliminating upward penetration deformation of a reinforced pile in a soft soil foundation, eliminating upper negative friction, and reducing the settlement of foundation or roadbed.
(4) The precast pile is used as the core pile. The construction of the precast file has a certain compaction effect on the filled soil foundation or loess foundation with collapsibility, which can completely or partially eliminate collapsibility, and reduce the risk of excessive settlement damage caused by foundation flooding.
(5) In subgrade engineering, the tensile stress of the reinforced material in the cushion layer is obviously reduced, which can save the engineering cost of the reinforced material.
(6) By adopting the technology of planting piles after long spiral soil drawing, the soil squeezing effect of the precast pile is reduced, the influence on the construction of the adjacent pile is reduced, and the construction quality of the precast pile composite foundation engineering is guaranteed.
The accompanying drawings, which constitute a part of the present disclosure, are used to provide a further understanding of the present disclosure, and the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an undue limitation of the present disclosure.
In the drawings: 100-T-shaped reamed pile; 200-soil between piles; 300-cushion layer; 400-upper foundation; 101-upper reamed body; 102-lower reamed body; 103-core pile.
The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.
In the description of the present disclosure, it needs to be understood that the orientation or positional relationship indicated by terms “upper”, “lower”, “front”, “rear”, “left” and “right” is based on the orientation or positional relationship shown in the drawings only for convenience of description of the present disclosure and simplification of description rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus are not to be construed as limiting the present disclosure.
In the description of the present disclosure, “a plurality of” means one or multiple, and the “multiple” means more than two. Greater than, less than, exceeding, etc. are understood as excluding this number, and above, below and within are understood as including this number. If the description to the first and the second is only for distinguishing technical features, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.
The present disclosure is described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.
For the problems that the existing precast pile is difficult in pile sinking, may disturb the surrounding soil and cannot pass through the hard sandwiched layer, a T-shaped reamed pile, a composite foundation, and a construction method for the composite foundation are provided. A hole is formed by drawing out soil with a drill bit with an aperture opening function and a long-spiral drill pipe, a material of a reamed body is poured into the pile hole, and then a precast core pile is inserted, thus reducing the difficulty of pile driving and reducing the damage to the precast pile.
A T-shaped reamed pile 100 provided by the present disclosure is composed of a core pile 103, and a reamed body surrounding the outside of the core pile 103. A depth of the core pile 103 is not lower than that of the reamed body. The reamed body includes an upper reamed body 101, and a lower reamed body 102, and a diameter of the upper reamed body 101 is larger than that of the lower reamed 102.
In a preferred embodiment of the present disclosure, the core pile 103 is a precast pile, and the reamed body is a cast-in-place reamed body.
In a preferred embodiment, the diameter of the upper reamed body 101 is 1.5-2.5 times an outer diameter of the core pile 103 (e.g., 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times), and a length of the upper reamed body 101 is 5-10 times the outer diameter of the core pile 103 (e.g., 6 times, 7 times, 8 times and 9 times). When the core pile 103 is a square pile, or other non-circular piles, the outer diameter of the core pile 103 refers to the maximum size of an outer wall of the core pile 103.
In a preferred embodiment of the present disclosure, the length of the upper reamed body 101 is not less than 2 m.
In a preferred embodiment, the material of the reamed body is selected from fine aggregate concrete, a cement-soil mixture, or a cement-bentonite slurry. The core pile 103 is selected from a prestressed concrete thin-walled pipe pile, a prestressed concrete square pile, a hollow square pile, or a prestressed concrete variable diameter pipe pile.
The present disclosure further provides a composite foundation. As shown in
In a preferred embodiment of the present disclosure, the cushion layer 300 is a sand-gravel cushion layer, or a reinforced cement-soil cushion layer. The cushion layer 300 has a thickness of 300-500 mm (e.g., 310 mm, 330 mm, 350 mm, 370 mm, 390 mm, 400 m, 410 mm, 430 mm, 450 mm, 470 mm, 490 mm).
In a preferred embodiment of the present disclosure, the cushion layer 300 is a reinforced cement-soil cushion layer, and a reinforced material of the cushion layer 300 is a double-layer steel plate mesh structure, and a thickness of a protective layer is not less than 80 mm.
The present disclosure further provides a construction method for the composite foundation, which is partially shown in
Step one, drawing out soil at a pile location by a drill bit with an aperture opening function and a long spiral drill pipe to form a hole, thus forming a T-shaped pile hole;
Step two, pouring a material of a reamed body into the T-shaped pile hole;
Step three, after the pouring of the material of the reamed body is completed, driving a core pile to a designed depth of the T-shaped pile hole by a static pile driver, a vibratory hammer, a hydraulic hammer, and other equipment; and
Step four, after the curing of the material of the reamed body is completed, constructing a cushion layer 300, where the cushion layer 300 is a sand-gravel cushion layer, or a reinforced cement-soil cushion layer.
In a preferred embodiment of the present disclosure, when the cushion layer 300 is the reinforced cement-soil cushion layer, the cement soil is constructed by a compaction method, and a compressive strength is not less than 3 MPa.
The T-shaped reamed pile, the composite foundation and the construction method for the composite foundation provided by the present disclosure are described in detail below with reference to specific embodiments.
This embodiment provides a composite foundation suitable for the construction of a foundation with a slightly collapsible soil layer as a soil layer around the pile and silt clay as a bearing stratum at the bottom of the pile. The composite foundation is composed of multiple T-shaped reamed piles 100, soil 200 between piles, and an upper cushion layer 300. Design parameters are as follows:
The T-shaped reamed pile 100 is composed of a core pile 103, and a reamed body surrounding the outside of the core pile 103. A depth of each of the core pile 103 and the reamed body is 12 m. The core pile 103 is a prestressed concrete thin-walled pipe pile with an outer diameter of 400 mm. The reamed body includes an upper reamed body 101, and a lower reamed body 102. The upper reamed body 101 has a diameter of 800 mm, and a length of 2 m, and the lower reamed body 102 has a diameter of 600 mm. The material used by the reamed body is fine aggregate concrete, and a clear distance between two adjacent T-shaped reamed piles 100 is 0.8 m.
The cushion layer 300 is a reinforced cement-soil cushion layer, and has a thickness of 480 mm. A reinforced material is a double-layer steel mesh structure, and a protective layer has a thickness of 100 mm. The cement soil is constructed by a compaction method, and a compressive strength after compaction is not less than 3 MPa. After detection, the ultimate bearing capacity of a single pile is 1800 KN, and the bearing capacity of the composite foundation is 220 kPa. The collapsibility of the soil between piles is eliminated by the compaction generated by the precast pile when driven into the hole, and an average collapsibility coefficient is 0.009. The composite foundation is suitable for the foundation treatment of buildings and structures such as houses, municipalities, and roads.
A construction method for a composite foundation includes the following steps:
Step one. After foundation-pit excavation is completed, a drill bit with an aperture opening function and a long spiral drill pipe are used to draw out soil at a designed pile location to form a hole. A T-shaped pile hole with an upper diameter larger than a lower diameter is formed, and the size of the T-shaped pile hole is the same as the designed size of the above T-shaped reamed pile 100.
Step two. A material of a reamed body is poured into the T-shaped pile hole by a pump truck through a connected pipeline and a long-spiral hollow drill pipe.
Step three. After the pouring of the material of the reamed body is completed, the drill pipe is pulled out, and a core pile 103 is driven into a designed depth of the T-shaped pile hole by a static pile driver, and a final pressure value of pile driving pressure is 700 kN.
Step four. After the curing of the material of the reamed body is completed, a reinforced cement-soil cushion layer is laid thereon, thus completing the construction of the composite construction. Afterwards, the construction of an upper foundation 400 or an embankment can be constructed on the composite foundation.
This embodiment provides a composite foundation. The composite foundation is composed of multiple T-shaped reamed piles 100, soil 200 between piles, and an upper cushion layer 300, which is suitable for the construction of a foundation with silt and silty clay as a soil layer around the pile, and a sand layer as a bearing stratum at the bottom of the pile, and all the silt and silty clay layer and the sand layers are non-collapsible soil layers. The design parameters are as follows:
The T-shaped reamed pile 100 is composed of a core pile 103, and a reamed body surrounding the outside of the core pile 103. A depth of each of the core pile 103 and the reamed body is 12 m. The core pile 103 is a prestressed concrete thin-walled pipe pile with an outer diameter of 400 mm. The reamed body includes an upper reamed body 101, and a lower reamed body 102. The upper reamed body 101 has a diameter of 800 mm, and a length of 2 m, and the lower reamed body 102 has a diameter of 600 mm. The material used by the reamed body is fine aggregate concrete, and a clear distance between two adjacent T-shaped reamed piles 100 is 0.8 m.
The cushion layer 300 is a sand-gravel cushion with a thickness of 500 mm, which is compacted in two layers with a compaction coefficient of 0.96.
After detection, the ultimate bearing capacity of a single pile is 2000 kN, and the bearing capacity of the composite foundation is 240 kPa.
A construction method for a composite foundation includes the following steps:
Step one. After foundation-pit excavation is completed, a drill bit with an aperture opening function and a long spiral drill pipe are used to draw out soil at a designed pile location to form a hole. A T-shaped pile hole with an upper diameter larger than a lower diameter is formed, and the size of the T-shaped pile hole is the same as the designed size of the above T-shaped reamed pile 100.
Step two. A material of a reamed body is poured into the T-shaped pile hole by a pump truck through a connected pipeline and a long-spiral hollow drill pipe.
Step three. After the pouring of the material of the reamed body is completed, the drill pipe is pulled out, and a core pile 103 is driven into a designed depth of the T-shaped pile hole by a static pile driver, and a final pressure value of pile driving pressure is 600 kN.
Step four. After the curing of the material of the reamed body is completed, a reinforced cement-soil cushion layer is laid thereon, thus completing the construction of the composite construction. Afterwards, the construction of an upper foundation 400 or an embankment can be constructed on the composite foundation.
This embodiment provides a composite foundation suitable for a collapsible soil layer. The composite foundation is composed of multiple T-shaped reamed piles 100, soil 200 between piles, and an upper cushion layer 300. Design parameters are as follows:
The T-shaped reamed pile 100 is composed of a core pile 103, and a reamed body surrounding the outside of the core pile 103. A depth of each of the core pile 103 and the reamed body is 10 m. The core pile 103 is a prestressed concrete square pile with an outer diameter of 300 mm. The reamed body includes an upper reamed body 101, and a lower reamed body 102. The upper reamed body 101 has a diameter of 750 mm, and a length of 2 m, and the lower reamed body 102 has a diameter of 450 mm. The material used by the reamed body is a cement-soil mixture, and a clear distance between two adjacent T-shaped reamed piles 100 is 0.5 m. After detection, the ultimate bearing capacity of a single pile is 1500 kN, and the bearing capacity of the composite foundation is 200 kPa.
The cushion layer 300 is a reinforced cement-soil cushion layer, and has a thickness of 300 mm. A reinforced material is a double-layer steel mesh structure, and a protective layer has a thickness of 80 mm. The cement soil is constructed by a compaction method, and a compressive strength after compaction is not less than 3 MPa.
A construction method for a composite foundation includes the following steps:
Step one. After foundation-pit excavation is completed, a drill bit with an aperture opening function and a long spiral drill pipe are used to draw out soil at a designed pile location to form a hole. A T-shaped pile hole with an upper diameter larger than a lower diameter is formed, and the size of the T-shaped pile hole is the same as the designed size of the above T-shaped reamed pile 100.
Step two. A material of a reamed body is poured into the T-shaped pile hole by a pump truck through a connected pipeline and a long-spiral hollow drill pipe.
Step three. After the pouring of the material of the reamed body is completed, the drill pipe is pulled out, and a core pile 103 is driven into a designed depth of the T-shaped pile hole by a vibratory hammer, with the number of hammerings of 100.
Step four. After the curing of the material of the reamed body is completed, a reinforced cement-soil cushion layer is laid thereon, thus completing the construction of the composite construction. Afterwards, the construction of an upper foundation 400 or an embankment can be constructed on the composite foundation.
This embodiment provides a composite foundation suitable for a collapsible soil layer. The composite foundation is composed of multiple T-shaped reamed piles 100, soil 200 between piles, and an upper cushion layer 300. Design parameters are as follows:
The T-shaped reamed pile 100 is composed of a core pile 103, and a reamed body surrounding the outside of the core pile 103. A depth of each of the core pile 103 and the reamed body is 15 m. The core pile 103 is a prestressed concrete variable diameter pile with an outer diameter of 500 mm. The reamed body includes an upper reamed body 101, and a lower reamed body 102. The upper reamed body 101 has a diameter of 1000 mm, and a length of 3.5 m, and the lower reamed body 102 has a diameter of 750 mm. The material used by the reamed body is a cement-bentonite slurry, and a clear distance between two adjacent T-shaped reamed piles 100 is 0.6 m. After detection, the ultimate bearing capacity of a single pile is 2300 kN, and the bearing capacity of the composite foundation is 270 kPa.
The cushion layer 300 is a reinforced cement-soil cushion layer, and has a thickness of 400 mm. A reinforced material is a double-layer steel mesh structure, and a protective layer has a thickness of 90 mm. The cement soil is constructed by a compaction method, and a compressive strength after compaction is not less than 3 MPa.
A construction method for a composite foundation includes the following steps:
Step one. After foundation-pit excavation is completed, a drill bit with an aperture opening function and a long spiral drill pipe are used to draw out soil at a designed pile location to form a hole. A T-shaped pile hole with an upper diameter larger than a lower diameter is formed, and the size of the T-shaped pile hole is the same as the designed size of the above T-shaped reamed pile 100.
Step two. A material of a reamed body is poured into the T-shaped pile hole by a pump truck through a connected pipeline and a long-spiral hollow drill pipe.
Step three. After the pouring of the material of the reamed body is completed, the drill pipe is pulled out, and a core pile 103 is driven into a designed depth of the T-shaped pile hole by a hydraulic hammer, with the number of hammerings of 220.
Step four. After the curing of the material of the reamed body is completed, a reinforced cement-soil cushion layer is laid thereon, thus completing the construction of the composite construction. Afterwards, the construction of an upper foundation 400 or an embankment can be constructed on the composite foundation.
This comparative example provides a prestressed concrete thin-walled pipe pile with a length of 12 m and an outer diameter of 600 mm. A test pile is carried out on the same site as in Embodiment 1 by using the static pile driver, where the pile driving pressure is 1800 kN, and the bearing capacity of a single pile is measured at 900 kN.
This comparative example provides a prestressed concrete square pile with a length of 10 m and an outer diameter of 450 mm. A test pile is carried out on the same site as in Embodiment 3 by using the vibratory hammer, where the number of hammerings is 880, and the bearing capacity of a single pile is measured at 1500 kN.
This comparative example provides a prestressed concrete variable diameter pipe pile with a length of 15 m and an outer diameter of 750 mm. A test pile is carried out on the same site as in Embodiment 4 by using the hydraulic hammer, where the number of hammerings is 1020, and the bearing capacity of a single pile is measured at 2300 kN.
As can be seen from the comparison of the embodiments and comparative examples, the T-shaped reamed pile 100 provided by the embodiment of the present disclosure can effectively reduce the difficulty of pile driving, the final pressure value of pile driving pressure is reduced by 30%-60%, and the number of hammerings is reduced by 30%-50%. The decrease of the pile driving pressure or the number of hammerings can reduce the damage to the precast pile.
After measurement, the bearing capacity of the single pile of the T-shaped reamed pile 100 provided by the present disclosure is remarkably higher than that of precast piles such as a prestressed concrete thin-walled pipe pile, and a prestressed concrete square pile, and thus the bearing capacity of the pile foundation can be remarkably improved.
The above is only the preferred embodiment of the present disclosure, and is not used to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311465995.4 | Nov 2023 | CN | national |
