Composite foundation and construction method thereof
By using prefabricated support and pile cap cover on soft soil foundations, combined with strong stirring of the cured soil layer and incorporating curing agent, the problems of rigid pile top stability and coordinated settlement between piles are solved, and efficient construction and stability improvement of composite foundations are achieved.
Patent Information
- Application Number
- CN202411971872.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-08
AI Technical Summary
When constructing on soft soil foundations, the existing technology is difficult to effectively solve the problems of rigid pile top stability and coordinated settlement of soil between piles, resulting in mushroom roads, pile cap tilts and pile caps to escape.
Prefabricated construction on the cured soil layer is used using prefabricated support and pile cap cover plate. The pile body passes through the prefabricated support and extends into the foundation. Through strong stirring of the cured soil layer and incorporating a curing agent, a stable cured soil layer is formed to support the rigid pile.
The problems of rigid pile top stability and coordinated settlement of soil between piles are effectively solved, and the problems of mushroom roads, pile cap tilt and pile cap emptying are avoided, which improves the overall bearing capacity and stability of the composite foundation.
Smart Images
Figure CN119777220A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of civil engineering technology, and in particular to a composite foundation and a construction method thereof. Background Art
[0002] Generally, the soft soil foundation without covering layer is firstly cleared of the damp and soft soil layer in the soft soil foundation, and then replaced with stable materials such as gravel and sand to improve the bearing capacity of the foundation. This method requires the excavation of a certain thickness of soft soil layer. It is difficult to find a suitable dumping site for this part of non-adaptable soil in the city, and the cost of replacing gravel, sand and other materials is high and uneconomical.
[0003] Conventional rigid piles include prestressed pipe piles, CFG piles, plain concrete piles and bored cast-in-place piles. Rigid piles have high pile body strength and high single pile bearing capacity. Rigid pile composite foundations formed by rigid pile combination consist of rigid piles, pile caps and cushion layers.
[0004] Before the construction of rigid piles, the site needs to be leveled. For foundations such as ponds without a covering soil layer, a certain thickness of fill needs to be filled first to form a hard shell layer on the soft foundation, and ensure that the bearing capacity of the foundation after the site is leveled meets the requirements of large-scale mechanical construction. The pile cap of a conventional rigid pile is generally a cast-in-place concrete structure. After the rigid pile construction is completed, the pile cap connection steel bars are embedded, and then the pile cap steel bars are tied. After the formwork is erected, the pile cap concrete is poured. The conventional rigid pile cap has little constraint on the rigid pile and can only transfer the upper load vertically. In addition, the pile cap itself has problems such as tilting and air loss under the pile cap.
[0005] For the roadbed, when the roadbed fill is less than 4m, especially when the fill thickness is less than 2m, if the original ground is directly leveled and prestressed pipe piles are constructed, the distance between the top of the pipe piles and the road surface is small, and it is difficult to form a soil arch effect. Under the action of the upper load, uneven soil settlement between piles will occur 2-3 years after construction, and mushroom road and other diseases will occur, affecting driving safety and comfort. Summary of the invention
[0006] In order to solve at least one of the above technical problems, the present application provides a composite foundation and a construction method thereof, and the technical solution adopted is as follows.
[0007] The construction method provided in this application uses prestressed pipe piles to construct a composite foundation, and the construction method includes the following construction steps:
[0008] Preparation for foundation construction, prefabrication of prefabricated support components and pile caps;
[0009] Solidified soil layer construction, solidifying the foundation surface within a set depth range to obtain a solidified soil layer;
[0010] Prefabricated support parts construction, after the in-situ soil solidification construction is completed, the position of the prefabricated support parts is measured within a set time, and the prefabricated support parts are arranged in the solidified soil layer;
[0011] Preparation for rigid pile construction: set a time after the solidified soil layer is constructed. When the solidified soil layer reaches the set index, clean up the earth in the prefabricated support and re-measure and stake out the rigid pile position;
[0012] In rigid pile construction, the prefabricated pile body is inserted from the prefabricated support into the soft soil foundation, and the bottom of the pile body enters the set soil layer or set depth of the foundation;
[0013] Clean the working surface of the prefabricated support member and the pile head of the pile body, wherein the pile head of the pile body is lower than the working surface of the inner ring support structure of the prefabricated support member;
[0014] Installation of prefabricated pile caps;
[0015] Roadbed filling construction.
[0016] In certain embodiments of the present application, the construction of the solidified soil layer includes: vigorously stirring the surface soil of the foundation and adding a solidifying agent.
[0017] In certain embodiments of the present application, the solidified soil layer is constructed in sections and blocks using a powerful mixing machine.
[0018] In certain embodiments of the present application, during the rigid pile construction preparation process, when the compressive strength of the solidified soil layer is greater than 0.2 MPa or the bearing capacity is greater than 80 Kpa, the rigid pile construction preparation work is carried out.
[0019] In certain embodiments of the present application, the pile body is aligned with the center of the pile position, and the bottom of the pile body is made to enter a set soil layer or a set depth of the foundation by static pressure construction or hammer construction.
[0020] In certain embodiments of the present application, the pile head of the pile body is 0.15 to 0.2 m lower than the working surface of the prefabricated support component, the gap between the pile body of the pile body and the inner ring support structure of the prefabricated support component is compacted, and the reinforced soil between the inner ring support structure and the outer ring support structure of the prefabricated support component is leveled.
[0021] In certain embodiments of the present application, after the prefabricated support and the pile body are cleaned, concrete is poured to fill the gap between the pile body and the inner ring support structure of the prefabricated support, and the top of the cast-in-place concrete is not less than 0.15m away from the working surface of the prefabricated support.
[0022] The construction method provided in this application uses bored cast-in-place piles to construct a composite foundation, and the construction method includes the following construction steps:
[0023] Preparation for foundation construction, prefabrication of prefabricated support components and pile caps;
[0024] Solidified soil layer construction, solidifying the foundation surface within a set depth range to obtain a solidified soil layer;
[0025] Prefabricated support parts construction, after the in-situ soil solidification construction is completed, the position of the prefabricated support parts is measured within a set time, and the prefabricated support parts are arranged in the solidified soil layer;
[0026] Preparation for rigid pile construction: set time after the solidified soil layer is constructed. When the solidified soil layer reaches the set index, re-measure and stake out the rigid pile position;
[0027] Rigid pile construction: drilling to a set soil layer or set depth, cleaning the hole, and pouring underwater concrete to obtain bored piles as the pile body;
[0028] Clean the working surface of the prefabricated support member and the pile head of the pile body, wherein the pile head of the pile body is lower than the working surface of the inner ring support structure of the prefabricated support member;
[0029] Installation of prefabricated pile caps;
[0030] Roadbed filling construction.
[0031] In certain embodiments of the present application, the rigid piles are replaced with CFG piles or plain concrete piles, and the construction method adopts the vibration pipe sinking method or the long spiral drilling method.
[0032] The composite foundation provided in the present application is constructed using the construction method described above.
[0033] In certain embodiments of the present application, the composite foundation includes a cured soil layer and at least two rigid piles distributed in an array, the rigid piles include a prefabricated support, a pile body and a pile cap cover, the prefabricated support includes a concentrically arranged inner ring support structure, an outer ring support structure and a radially arranged connecting arm.
[0034] In certain embodiments of the present application, the pile cap cover plate is a prefabricated C30 reinforced concrete structure with an upper and lower circular structure.
[0035] The present application has at least the following beneficial effects: In the technical solution of the present application, the soft soil on the surface of the foundation is solidified in situ to transform the foundation to obtain a solidified soil layer, a prefabricated support and a pile cap cover are arranged in the solidified soil layer, and the pile body is passed through the prefabricated support and extended into the foundation, thereby solving the problems of the top stability of the rigid pile and the coordinated settlement of the soil between the piles, and avoiding the mushroom road, pile cap tilting and pile cap falling caused by the low filling of the rigid pile construction. The present application can be widely used in the field of civil engineering technology.
[0036] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The present application is further illustrated below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments embodied in the following drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0038] Figure 1 This is the structural diagram of the rigid pile.
[0039] Figure 2 This is a structural diagram of the prefabricated support.
[0040] Figure 3 Schematic diagram of the construction process of rigid piles.
[0041] Figure 4 Schematic diagram of the distribution of rigid piles on the composite foundation.
[0042] Reference numerals: prefabricated support member 1100 ; inner ring support structure 1101 ; outer ring support structure 1102 ; connecting arm 1103 ; pile body 1200 ; pile cap plate 1300 . DETAILED DESCRIPTION
[0043] Combine the following Figures 1 to 4 The embodiments of the present application are described in detail, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0044] In the description of the present application, it should be understood that the terms "center", "middle", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, 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 application.
[0045] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0046] In the description of this application, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0047] In the description of the present application, if there is a description with reference to the terms "one embodiment", "some embodiments", "an embodiment", "some examples", "some embodiments", "illustrative embodiment", "example", "specific example", "some examples", etc., it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0048] The present application relates to a composite foundation. The composite foundation is used for soft foundation treatment of roads in deep soft soil areas. The composite foundation is provided with at least two rigid piles distributed in an array.
[0049] Further, the composite foundation includes a solidified soil layer formed on the surface of the foundation. It is understandable that the foundation is a soft foundation section, so the surface of the foundation needs to be solidified.
[0050] The rigid pile includes a prefabricated support 1100, a pile body 1200 and a pile cap plate 1300. The prefabricated support 1100 is arranged in the solidified soil layer, and the prefabricated support 1100 serves as the top support of the rigid pile. The pile cap plate 1300 is arranged on the top of the prefabricated support 1100, one end of the pile body 1200 is located on the prefabricated support 1100, the pile body 1200 is connected to the pile cap plate 1300, and the other end of the pile body 1200 extends into the foundation.
[0051] Further, the prefabricated support 1100 includes an inner ring support structure 1101 and an outer ring support structure 1102 which are arranged concentrically, the inner ring support structure 1101 and the outer ring support structure 1102 are both arranged in a circular shape and arranged concentrically, and the outer side wall of the inner ring support structure 1101 and the outer ring support structure 1102 are installed via at least two connecting arms 1103. Specifically, the connecting arm 1103 is arranged along the radial direction of the inner ring support structure 1101 and the outer ring support structure 1102, one end of the connecting arm 1103 is connected to the inner ring support structure 1101, and the other end of the connecting arm 1103 is connected to the outer ring support structure 1102.
[0052] The side of the pile cap cover plate 1300 facing the prefabricated support member 1100 is connected to the inner ring support structure 1101, and one end of the pile body 1200 is located in the inner ring support structure 1101. Specifically, the pile top of the pile body 1200 is located in the inner ring support structure 1101, the pile top of the pile body 1200 is lower than the top of the inner ring support structure 1101, and the pile bottom of the pile body 1200 extends to the bearing layer. Further, the lower side of the pile cap cover plate 1300 is connected to the inner ring support structure 1101, and the inner ring support structure 1101 has a restraining effect on the pile cap cover plate 1300, preventing the rigid pile from tilting under the action of external force.
[0053] It should be noted that the composite foundation solves the problems of top stability of rigid piles and coordinated settlement of soil between piles by setting prefabricated supporting parts 1100 and pile cap covers 1300, thus avoiding the problems of mushroom roads, tilted pile caps, and empty pile caps caused by too low fill in rigid pile construction.
[0054] In some embodiments, the pile body 1200 is configured as a prestressed pipe pile. The pile body 1200 is driven into the center of the pile position, and the gap between the outer wall of the pile body 1200 and the inner wall of the inner ring support structure 1101 is filled with concrete.
[0055] It can be understood that the space between the outer wall of the pile body 1200 and the inner wall of the inner ring support structure 1101 is densely filled with concrete, which can ensure that the top of the pile body 1200 is not deformed.
[0056] It should be noted that the filled concrete must also ensure that the pile top of the pile body 1200 is lower than the top of the inner ring support structure 1101 so that the pile cap cover plate 1300 can be installed.
[0057] In some embodiments, the pile body 1200 is configured as a bored pile, a hole is drilled in the center of the pile position, concrete is poured into the pile body, and steel bars are anchored in the feather pile cap.
[0058] In some embodiments, a boss is provided on the side of the pile cap cover plate 1300 facing the prefabricated support member 1100, and the boss is embedded in the inner ring support structure 1101. The boss plays the role of positioning the pile cap, transmitting vertical force, and restraining the deformation of the pile cap.
[0059] Furthermore, the pile cap plate 1300 is configured as a precast concrete structure.
[0060] In some examples, the pile cap plate 1300 is provided as a rectangular plate to form a square shape with a large bearing area.
[0061] The upper square bearing area is large, with a side length of 2.0m×2.0m and a thickness of 0.15m. The bottom is a raised circular structure with a diameter of 0.69m and a thickness of 0.15m. The raised part needs to be completely embedded in the inner ring supporting structure to position the pile cap, transmit vertical force and constrain the deformation of the pile cap.
[0062] The reinforced concrete cover plate uses two layers of steel mesh, the upper steel mesh is square with a specification of 1.9m×1.9m, and the lower steel mesh is round with a diameter of 0.59m. The two layers of steel mesh are connected and fixed with frame bars.
[0063] In the pile cap steel mesh, a lifting eye steel bar needs to be embedded in the center to facilitate the lifting and installation of the finished product.
[0064] It can be understood that the boss is configured as a cylindrical boss to adapt to the shape of the inner ring support structure 1101 .
[0065] It should be noted that when the pile cap cover plate 1300 is prefabricated, a lifting eye steel bar is embedded in the steel bar skeleton of the pile cap to facilitate the lifting and installation of the finished product of the pile cap cover plate 1300.
[0066] In some embodiments, the prefabricated support member 1100 is configured as a prefabricated concrete structure, and a steel frame is provided in the inner ring support structure 1101, the outer ring support structure 1102 and the connecting arm 1103. The steel frames of the three are connected to form a whole, and then concrete is poured to form an integral body.
[0067] The connecting arms 1103 are arranged at intervals along the annular direction between the outer side wall of the inner ring support structure 1101 and the inner side wall of the outer ring support structure 1102. Further, the connecting arms 1103 are distributed at equal intervals.
[0068] In some examples, the tops of the inner ring supporting structure 1101 , the outer ring supporting structure 1102 , and the connecting arms 1103 are at the same height.
[0069] In some examples, four connecting arms 1103 are provided.
[0070] In this application, the inner ring support structure, the outer ring support structure and the radially arranged connecting arms are all cast in one piece using concrete. The inner diameter of the inner ring support structure is 700mm, the outer diameter of the inner ring support structure is 800mm, the inner diameter of the outer ring support structure is 1500mm, the three-dimensional outer diameter of the outer ring support structure is 1600mm, and the height is about 500mm. Four connecting arms are arranged between the inner ring support structure and the outer ring support structure, with a width of 700mm, a height of 500mm, and a thickness of 100mm. The four connecting arms are evenly spaced and distributed in a ring.
[0071] The connecting arm is at the same height as the inner ring supporting structure and the outer ring supporting structure. The concrete thickness of the above components is 100mm and they are cast in one piece using concrete.
[0072] The present application relates to a construction method for a composite foundation. The construction method is used to construct a composite foundation, and the rigid piles in the composite foundation adopt prestressed pipe piles.
[0073] The construction method includes the following construction steps.
[0074] (1) Foundation construction preparation
[0075] Carry out surface clearing, water extraction, drying and leveling operations, prepare the curing construction machinery and materials, and prepare the pile body 1200, prefabricated support members 1100 and pile cap cover plates 1300.
[0076] (2) Solidification of soil layer
[0077] The surface layer of the foundation is solidified within a set depth range to obtain a solidified soil layer. Specifically, the solidified soil layer construction includes: vigorously stirring the surface layer of the foundation and adding a solidifying agent.
[0078] A powerful mixing machine is used to vigorously mix the surface layer of the foundation within a set depth range, and the depth of the solidified soil layer is 1 to 1.5m.
[0079] The solidified soil layer is constructed in situ by dividing and blocking.
[0080] (3) Construction of prefabricated support parts 1100
[0081] After the in-situ soil solidification construction is completed within a set time, the position of the rigid piles is measured and the prefabricated support members 1100 are arranged in the solidified soil layer.
[0082] Taking advantage of the low initial strength of the solidified soil layer, the prefabricated support member 1100 is aligned with the pile position of the pile body 1200 and pressed into the solidified soil layer to ensure that the top of the outer ring support structure 1102 is flush with the surface of the solidified soil layer.
[0083] (4) Rigid pile construction preparation
[0084] After a set time has passed since the solidified soil layer was constructed, when the solidified soil layer reaches the set index, the earth in the prefabricated support member 1100 is cleared, and the rigid pile position is measured and laid out again.
[0085] During the rigid pile construction preparation, when the compressive strength of the solidified soil layer is greater than 0.2MPa or the bearing capacity is greater than 80Kpa, the rigid pile construction preparation work is started. The earthwork in the inner ring support structure 1101 is cleared, and the position of the rigid pile is measured and laid out again.
[0086] (5) Rigid pile construction
[0087] The prefabricated pile body 1200 is arranged on the prefabricated supporting member 1100 , and the pile bottom of the pile body 1200 enters a set soil layer or a set depth of the foundation.
[0088] If the pile body 1200 is a bored cast-in-place pile, a hole is drilled to a set soil layer or a set depth, and concrete is poured to obtain a bored cast-in-place pile as the pile body 1200 .
[0089] (6) Cleaning the working surface of the prefabricated support 1100
[0090] After the construction of the pile body 1200 is completed, the pile head of the pile body 1200 and the working surface of the prefabricated support 1100 are cleaned, and the working surface is located at the top of the prefabricated support 1100, ensuring that the pile head of the pile body 1200 is lower than the working surface of the inner ring support structure 1101 of the prefabricated support. Specifically, the pile head of the pile body 1200 is 0.15 to 0.2 m lower than the working surface of the prefabricated support 1100.
[0091] The gap between the pile body of the pile body 1200 and the inner ring supporting structure 1101 is compacted, and the solidified soil layer between the outer side wall of the inner ring supporting structure 1101 and the inner side wall of the outer ring supporting structure 1102 is leveled.
[0092] It should be noted that, when the pile body 1200 is a prestressed pipe pile, the top of the pipe pile should be sealed first. Specifically, the top of the pipe pile is sealed with a steel plate.
[0093] After finishing, pour concrete to fill the gap between the pile body and the inner ring support structure 1101, and make the concrete between the pipe pile and the inner ring support structure 1101 filled and vibrated to make it dense. Make sure that the top of the pile body 1200 is 0.15 to 0.16m lower than the top of the inner ring support structure 1101 after filling.
[0094] The top of the cast-in-place concrete is at least 0.15m away from the working surface of the prefabricated support 1100.
[0095] (7) Installation of prefabricated pile cap 1300
[0096] Clean and compact the reinforced soil in the prefabricated support 1100, and level and compact the solidified soil layer outside the prefabricated support 1100 and under the pile cap cover 1300.
[0097] The pile cap plate 1300 is installed by using a lifting device, and the boss of the pile cap plate 1300 is embedded in the inner ring support structure 1101 .
[0098] (8) Roadbed filling construction
[0099] After the construction of pile cap cover 1300 is completed, the roadbed filling construction will be carried out.
[0100] The present application relates to a construction method for a composite foundation. The construction method is used to construct a composite foundation, and the rigid piles in the composite foundation are bored cast-in-place piles.
[0101] The construction method includes the following construction steps.
[0102] (1) Foundation construction preparation
[0103] Carry out surface clearing, water extraction, drying and leveling operations, prepare the curing construction machinery and materials, and prepare the pile body 1200, prefabricated support members 1100 and pile cap cover plates 1300.
[0104] (2) Solidification of soil layer
[0105] The surface layer of the foundation is solidified within a set depth range to obtain a solidified soil layer. Specifically, the solidified soil layer construction includes: vigorously stirring the surface layer of the foundation and adding a solidifying agent.
[0106] A powerful mixing machine is used to powerfully mix the surface layer of the foundation within a set depth range.
[0107] The solidified soil layer is constructed in situ by dividing and blocking.
[0108] (3) Construction of prefabricated support parts 1100
[0109] After the in-situ soil solidification construction is completed within a set time, the position of the rigid piles is measured and the prefabricated support members 1100 are arranged in the solidified soil layer.
[0110] Taking advantage of the low initial strength of the solidified soil layer, the prefabricated support member 1100 is aligned with the pile position of the pile body 1200 and pressed into the solidified soil layer to ensure that the top of the outer ring support structure 1102 is flush with the surface of the solidified soil layer.
[0111] (4) Rigid pile construction preparation
[0112] After a set time has passed since the solidified soil layer was constructed, when the solidified soil layer reaches the set index, the earth in the prefabricated support member 1100 is cleared, and the rigid pile position is measured and laid out again.
[0113] During the rigid pile construction preparation, when the compressive strength of the solidified soil layer is greater than 0.2MPa or the bearing capacity is greater than 80Kpa, the rigid pile construction preparation work is started. The earthwork in the inner ring support structure 1101 is cleared, and the position of the rigid pile is measured and laid out again.
[0114] (5) Rigid pile construction
[0115] The prefabricated pile body 1200 is arranged on the prefabricated supporting member 1100 , and the pile bottom of the pile body 1200 enters a set soil layer or a set depth of the foundation.
[0116] If the pile body 1200 is a prestressed pipe pile, since the prestressed pipe pile is a soil-squeezing pile, static pressure construction or hammering construction is adopted. Specifically, the pile body 1200 is aligned with the center of the pile position, and the pile bottom of the pile body 1200 enters the set soil layer or set depth of the foundation by static pressure construction or hammering construction.
[0117] It should be noted that when the bearing capacity of the site is not high, hammer pipe pile construction is preferred.
[0118] (6) Cleaning the working surface of the prefabricated support 1100
[0119] After the construction of the pile body 1200 is completed, the pile head of the pile body 1200 and the working surface of the prefabricated support 1100 are cleaned, and the working surface is located at the top of the prefabricated support 1100, ensuring that the pile head of the pile body 1200 is lower than the working surface of the inner ring support structure 1101 of the prefabricated support. Specifically, the pile head of the pile body 1200 is 0.15 to 0.2 m lower than the working surface of the prefabricated support 1100.
[0120] The gap between the pile body of the pile body 1200 and the inner ring supporting structure 1101 is compacted, and the solidified soil layer between the outer side wall of the inner ring supporting structure 1101 and the inner side wall of the outer ring supporting structure 1102 is leveled.
[0121] It should be noted that, when the pile body 1200 is a prestressed pipe pile, the top of the pipe pile should be sealed first. Specifically, the top of the pipe pile is sealed with a steel plate. After the arrangement is completed, concrete is poured to fill the gap between the pile body and the inner ring support structure 1101, so that the concrete between the pipe pile and the inner ring support structure 1101 is filled and vibrated to be dense.
[0122] The top of the cast-in-place concrete is at least 0.15m away from the working surface of the prefabricated support 1100.
[0123] (7) Installation of prefabricated pile cap 1300
[0124] Clean and compact the reinforced soil in the prefabricated support 1100, and level and compact the solidified soil layer outside the prefabricated support 1100 and under the pile cap cover 1300.
[0125] The pile cap plate 1300 is installed by using a lifting device, and the boss of the pile cap plate 1300 is embedded in the inner ring support structure 1101 .
[0126] (8) Roadbed filling construction
[0127] After the construction of pile cap cover 1300 is completed, the roadbed filling construction will be carried out.
[0128] Based on the introduction of the above composite foundation and construction method, the technical solution of the present application has at least the following beneficial effects.
[0129] The composite foundation and construction method of the present application are based on soft foundation sections with no covering soil or thin covering soil. The conventional filling process is replaced by an in-situ solidified soil layer on the surface, which makes full use of the existing foundation, reduces earth and stone excavation, forms a solidified soil layer on the foundation surface, creates conditions for subsequent pipe pile construction, and is more low-carbon and environmentally friendly.
[0130] In the present application, the pile cap cover plate 1300 adopts a rectangular prefabricated reinforced concrete structure, which increases the area compared to the conventional pile cap, thereby increasing the load-bearing area. The pile spacing of the rigid pile is increased to 6 to 8D (D is the diameter of the pile body 1200). The technical solution of the present application achieves the purpose of increasing the bearing capacity of a single pile and reducing the roadbed settlement by increasing the pile spacing, increasing the pile cap cover plate 1300, and increasing the depth of the pile bottom entering the bearing layer. On the other hand, increasing the pile spacing can also reduce the engineering cost of the composite foundation and reduce the soil squeezing effect.
[0131] Conventional pile caps have large cantilevers and poor stability, and the pile cap cover plate 1300 is mainly supported on rigid piles. When the soil between the piles undergoes consolidation and settlement, the pile caps may become hollow, etc. However, the composite foundation and construction method of the present application can effectively overcome such problems.
[0132] During the implementation of the technical solution of the present application, the original soil is fully utilized as much as possible without filling, abandoning or replacing the soil. The original foundation soil is hardened in situ by adding cement or other curing agents, which brings convenience to the subsequent rigid pile construction. It can also serve as a carrier for fixing the pile cap and exerting the bearing capacity of the soil between piles.
[0133] The composite foundation of the present application is provided with a prefabricated support 1100 dedicated to the rigid pile, which can, on the one hand, provide constraints on the top of the rigid pile to prevent the rigid pile from tilting. On the other hand, the prefabricated support 1100 can also serve as a support for the pile cap. The prefabricated support 1100 is embedded in the solidified soil layer. Through the friction between the side wall of the prefabricated support 1100 and the solidified soil layer, it can ensure that the settlement of the solidified soil layer inside and outside the prefabricated support 1100 remains consistent, avoiding the problem of the pile cap tilting and the pile cap falling off. The prefabricated support 1100 is arranged in the solidified soil layer, which is equivalent to reinforcing the solidified soil layer, thereby improving the overall strength of the solidified soil layer.
[0134] The technical solution of the present application not only utilizes the characteristics of prestressed single piles or bored cast-in-place piles, such as high bearing capacity, large processing depth, reliable pile quality, fast construction speed, and small settlement after processing, but also utilizes the characteristics of prefabricated support members 1100, such as large bearing area, convenient construction, and reliable quality. At the same time, the strength of the foundation is improved by adding curing agents, etc., and the role of the soft soil on the surface is fully utilized, providing conditions for the support of the pile cap cover plate 1300 and the pile body 1200.
[0135] The prefabricated support member 1100 and the pile cap plate 1300 in the rigid pile of the present application adopt a prefabricated structure, which can save construction time to the maximum extent. On the other hand, the quality of the prefabricated concrete structure is reliable and guaranteed, and it is low-carbon and environmentally friendly.
[0136] The above is a detailed description of the implementation methods of the present application in conjunction with the accompanying drawings, but the present application is not limited to the above implementation methods. Various changes can be made within the knowledge of ordinary technicians in the technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.
Claims
1. A construction method for a composite foundation, characterized in that: The construction method uses prestressed pipe piles to build a composite foundation, and the construction method includes Preparation for foundation construction, prefabrication of prefabricated support components and pile caps; Solidified soil layer construction, solidifying the foundation surface within a set depth range to obtain a solidified soil layer; Prefabricated support parts construction, after the in-situ soil solidification construction is completed, the position of the prefabricated support parts is measured within a set time, and the prefabricated support parts are arranged in the solidified soil layer; Preparation for rigid pile construction: set a time after the solidified soil layer is constructed. When the solidified soil layer reaches the set index, clean up the earth in the prefabricated support and re-measure and stake out the rigid pile position; In rigid pile construction, the prefabricated pile body is inserted into the soft soil foundation from the prefabricated support, and the bottom of the pile body enters the set soil layer or set depth of the foundation; Clean the working surface of the prefabricated support member and the pile head of the pile body, wherein the pile head of the pile body is lower than the working surface of the inner ring support structure of the prefabricated support member; Installation of prefabricated pile caps; Roadbed filling construction.
2. The construction method of the composite foundation according to claim 1, characterized in that: The solidified soil layer construction includes: vigorously stirring the surface soil of the foundation and adding a solidifying agent; and constructing the solidified soil layer in sections and blocks using a powerful stirring machine.
3. The construction method of the composite foundation according to claim 1, characterized in that: The rigid pile construction preparation includes: when the compressive strength of the solidified soil layer is greater than 0.2MPa or the bearing capacity is greater than 80Kpa, the rigid pile construction preparation work is carried out; the pile body is aligned with the center of the pile position, and the bottom of the pile body is made to enter the set soil layer or set depth of the foundation by static pressure construction or hammer construction.
4. The construction method of the composite foundation according to claim 1, characterized in that: The pile head of the pile body is 0.15 to 0.2 m lower than the working surface of the prefabricated support, the gap between the pile body of the pile body and the inner ring support structure of the prefabricated support is compacted, and the reinforced soil between the inner ring support structure and the outer ring support structure of the prefabricated support is leveled.
5. The construction method of the composite foundation according to claim 1, characterized in that: After cleaning the precast supporting parts and the pile body, pour concrete to fill the gap between the pile body and the inner ring supporting structure of the precast supporting parts. The top of the cast-in-place concrete should be no less than 0.15m away from the working surface of the precast supporting parts.
6. A construction method for a composite foundation, characterized in that: The construction method uses bored cast-in-place piles to build a composite foundation, and the construction method includes Preparation for foundation construction, prefabrication of prefabricated support components and pile caps; Solidified soil layer construction, solidifying the foundation surface within a set depth range to obtain a solidified soil layer; Prefabricated support parts construction, after the in-situ soil solidification construction is completed, the position of the prefabricated support parts is measured within a set time, and the prefabricated support parts are arranged in the solidified soil layer; Preparation for rigid pile construction: set time after the solidified soil layer is constructed. When the solidified soil layer reaches the set index, re-measure and stake out the rigid pile position; Rigid pile construction: drilling to a set soil layer or set depth, cleaning the hole, and pouring underwater concrete to obtain bored piles as the pile body; Clean the working surface of the prefabricated support member and the pile head of the pile body, wherein the pile head of the pile body is lower than the working surface of the inner ring support structure of the prefabricated support member; Installation of prefabricated pile caps; Roadbed filling construction.
7. The construction method of the composite foundation according to claim 6, characterized in that: The rigid piles are replaced with CFG piles or plain concrete piles, and the construction method adopts the vibration pipe sinking method or the long spiral drilling method.
8. A composite foundation, characterized in that: The composite foundation is constructed using the construction method described in any one of claims 1 to 7.
9. The composite foundation according to claim 8, characterized in that: The composite foundation includes a solidified soil layer and at least two rigid piles distributed in an array, wherein the rigid piles include prefabricated supports, a pile body and a pile cap cover plate, and the prefabricated supports include a concentrically arranged inner ring support structure, an outer ring support structure and radially arranged connecting arms.
10. The composite foundation according to claim 8, characterized in that: The pile cap cover is a prefabricated reinforced concrete structure with an upper and lower circular structure.