Rigidity-variable pile-supported embankment structure based on stiff composite piles

Abstract

The utility model discloses a stiffness-variable pile-supported embankment structure based on stiff composite piles, which belongs to the technical field of civil engineering and comprises a plurality of stiff composite piles, a plurality of plain cement soil piles, a plurality of geotechnical bags and a bearing platform. The stiff composite pile comprises a cement soil outer core and a concrete inner core fixedly inserted into the cement soil outer core. The plurality of stiff composite piles and the plurality of plain cement soil piles are inserted into the foundation; a plurality of soil engineering bags are stacked on the pile tops of the stiff composite piles and the plain cement soil piles to form a plurality of soil engineering bag layers; and the bearing platform is fixed on the geotechnical bag layer. The bearing capacity, the shock absorption and isolation performance and the economic applicability of the stiff composite pile can be greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of civil engineering, and relates to a pile-supported embankment structure, in particular to a variable-stiffness pile-supported embankment structure based on rigid composite piles. Background Art

[0002] In the existing road design specifications, the vehicle load is simplified as the static load of a certain thickness of soil layer, without considering the dynamic effect of traffic load. Due to the lane setting, the traffic dynamic load has the characteristic of uneven load distribution, and due to different peak periods, it has the characteristic of non-constancy. Especially in some special parts, such as the turning point, the joint between the road and the bridge, etc., the amplitude of unevenness and non-constancy is greater. If the important influence of the unevenness and non-constancy of traffic load on the long-term cyclic effect is ignored, it will lead to problems such as the weakening of the strength and modulus of the road and embankment structure, and uneven settlement of the foundation, which will greatly shorten the service life of the pile-supported embankment structure.

[0003] As a new type of composite pile, due to its excellent performance in strengthening soft soil and other weak soil layers, the rigid composite pile has been widely used in the eastern coastal areas. Compared with ordinary piles, the rigid composite pile combines the characteristics of large stiffness of the inner core concrete core, close interaction between the outer core cement-soil pile and the soil, and excellent economic performance, and is widely used in the foundations of industrial, civil, road, and storage facilities.

[0004] With the application of rigid composite piles in highway foundations, it is urgent to study how to remove or weaken the adverse effects brought by the unevenness and instability of highway loads on the pile-supported embankment structure, and design a pile-supported embankment structure that can effectively avoid uneven settlement of pile foundations. Content of the Utility Model

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a variable-stiffness pile-supported embankment structure based on rigid composite piles, which is used for the layout of rigid composite piles under highway loads, and can greatly improve the bearing capacity, seismic isolation and vibration reduction performance, and economic applicability of rigid composite piles.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] The variable-stiffness pile-supported embankment structure based on rigid composite piles includes a number of rigid composite piles, a number of plain cement-soil piles, a number of geotextile bags and a bearing platform; the rigid composite pile includes a cement-soil outer core and a concrete inner core fixedly inserted in the cement-soil outer core; a number of rigid composite piles and a number of plain cement-soil piles are all inserted into the foundation; a number of geotextile bags are stacked on the pile tops of a number of rigid composite piles and a number of plain cement-soil piles to form a number of geotextile bag layers; the bearing platform is fixed on the geotextile bag layer.

[0008] To optimize the above technical solution, the specific measures taken also include:

[0009] Furthermore, among several stiffened composite piles, every five stiffened composite piles are arranged to form a "cross" structure.

[0010] Furthermore, in the "cross" structure, the cement-soil outer core of the central stiffened composite pile coincides with the cement-soil outer cores of the surrounding stiffened composite piles.

[0011] Furthermore, in the "cross" structure, the pile bottom of the cement-soil outer core of the central stiffened composite pile has a spherical cement-expanded head.

[0012] Furthermore, several plain cement-soil piles connect several "cross" structures into a row of combined pile foundations; the variable stiffness pile-supported embankment structure includes several rows of combined pile foundations.

[0013] Furthermore, the plain cement-soil pile coincides with the cement-soil outer core of the adjacent stiffened composite pile.

[0014] Furthermore, on the side of the combined pile foundation where the force is large, there is a cement-soil extended reinforcement section composed of several plain cement-soil piles.

[0015] Furthermore, the concrete pouring material of the concrete inner core is a geopolymer cementitious material. The cement material of the cement-soil outer core is a geopolymer cementitious material.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. Through the arrangement form of stiffened composite piles with different concrete inner core lengths and connecting plain cement-soil piles, the present utility model can controllably change the structural stiffness according to the bearing requirements, while ensuring the bearing capacity of the combined stiffened composite pile group piles, and taking into account economic and environmental applicability. Specifically, in order to adapt to the characteristics of uneven road loads and strong dynamic characteristics, a combined pile foundation of stiffened composite piles and plain cement-soil piles is used as the lower structure, and the upper load requirements are met by adjusting the concrete inner core length (equal-core, short-core, long-core stiffened composite piles), the inner and outer core pile lengths, the combined pile foundation length, etc.; at the same time, by expanding the pile head (cement-expanded head) at the lower part, the overall uplift resistance of the pile foundation is effectively improved, and the stability of the overall structure is enhanced.

[0018] 2. Different from the existing combination of pure stiffened composite piles, the present utility model adopts a "cross expansion" pile type formed by stiffened composite piles and plain cement-soil, and the structure is more suitable for highway bearing and can better exert the stability of the overall structure.

[0019] III. Geotextile bags are stacked on the pile top of the present utility model. Under the action of the upper bearing platform and highway load, the self-adjusting stiffness function of the rigid composite pile can be realized. At the same time, during the process of the pile body piercing into the upper geotextile bags, the geotextile bags can fully exert their ductility, enhance the interaction between the pile body, the overall geotextile bags and the bearing platform, effectively weaken the adverse effects of uneven and unstable upper traffic loads on the pile-supported subgrade, and achieve an effective seismic isolation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the front sectional view of the variable stiffness pile-supported embankment structure;

[0021] Figure 2 is the side sectional view of the variable stiffness pile-supported embankment structure;

[0022] Figure 3 is the top view of several rows of combined pile foundations in the variable stiffness pile-supported embankment structure;

[0023] Figure 4 is the structural schematic diagram of the variable stiffness pile-supported embankment structure applied to a curved road;

[0024] Figure 5 is the top view of the variable stiffness pile-supported embankment structure applied to a curved road;

[0025] The reference signs in the drawings are:

[0026] 1, rigid composite pile; 11, cement-soil outer core; 12, concrete inner core; 2, plain cement-soil pile; 3, geotextile bag; 4, bearing platform; 5, cement-soil extended reinforcement section. SPECIFIC EMBODIMENT

[0027] The following describes the specific embodiment of the present utility model with reference to the drawings.

[0028] As Figure 1 and 2 shown, the present utility model provides a variable stiffness pile-supported embankment structure based on rigid composite piles, including several rigid composite piles 1, several plain cement-soil piles 2, several geotextile bags 3 and a bearing platform 4.

[0029] The rigid composite pile 1 includes a cement-soil outer core 11 and a concrete inner core 12 fixedly inserted in the cement-soil outer core 11. Several rigid composite piles 1 and several plain cement-soil piles 2 are all inserted into the foundation.

[0030] Specifically, among several rigid composite piles 1, every five rigid composite piles 1 are arranged to form a "cross" structure. In the "cross" structure, the cement-soil outer cores 11 of the central rigid composite pile 1 coincide with the cement-soil outer cores 11 of the surrounding rigid composite piles 1. The bottom of the cement-soil outer core 11 of the central rigid composite pile 1 has a spherical cement head enlargement 13.

[0031] As Figure 3 shown, several plain cement-soil piles 2 connect several "cross" structures into a row of combined pile foundations, and the variable stiffness pile-supported embankment structure includes several rows of combined pile foundations. The plain cement-soil pile 2 coincides with the cement-soil outer core 11 of the adjacent stiffened composite pile 1.

[0032] Among them, the concrete inner core 12 of the stiffened composite pile 1 is precast. The traditional inner core concrete pouring material is ordinary Portland cement raw material, while in this structure, the inner core concrete pouring material adopts low-carbon materials, specifically geopolymer cementitious materials. Compared with ordinary Portland cement raw materials, the composition of geopolymer cementitious materials has several more raw materials such as SiO2, Al2O3, CaO, MgO, and K2O+Na2O, and is similar to the properties of ceramics. Moreover, inorganic polymers with Si, Al, etc. connected by covalent bonds into a skeleton have advantages such as firm connection and good durability. Most importantly, geopolymers have rich raw material resources, low energy consumption, almost no pollution, and do not consume limestone resources, and are an environmentally friendly green building material. Geopolymer cementitious materials are existing materials, and their composition and process will not be elaborated here.

[0033] The cement-soil outer core 11 of the stiffened composite pile 1 is constructed on-site. To achieve the goal of green environmental protection, its cement material also adopts geopolymer cementitious materials.

[0034] The cement head enlargement 13 is formed when the cement-soil mixing machine is mixing and constructing to the lowest part. The cement output on the sidewall is closed, and only the cement output downward at the lowest part is left, and it is diffused outward by pressurization to finally form a spherical head enlargement. The cement head enlargement 13 can not only increase the overall bearing capacity of the pile foundation, but also greatly improve the uplift resistance of the pile foundation, and effectively resist the influence of adverse factors such as groundwater on the pile foundation structure.

[0035] The plain cement-soil pile 2 is also constructed on-site.

[0036] Several geotextile bags 3 are stacked on the pile tops of several stiffened composite piles 1 and several plain cement-soil piles 2 to form several layers of geotextile bag layers.

[0037] The bearing platform 4 is fixed on the geotextile bag layer.

[0038] Several geotextile bags 3 are arranged on the pile tops. By neatly stacking, the pile tops of the stiffened composite piles 1 and the plain cement-soil piles 2 are connected to the upper bearing platform 4. When uneven settlement occurs in the lower pile foundation, the geotextile bags 3 on the pile tops at the higher points are compressed, realizing stiffness self-adjustment and preventing the bearing platform 4 structure from being damaged. The geotextile bags 3 can generate deformation through their own compression to coordinate the stability of the overall structure, effectively avoiding the influence of uneven settlement of the pile foundation caused by the large middle and small ends of the upper road load, and greatly extending the service life of the pile foundation.

[0039] The bearing platform 4 is a structure that transfers the load of the upper structure to the lower pile foundation and is cast with reinforced concrete. After the construction of the lower pile foundation is completed, the geotextile bags 3 are stacked immediately, and finally the steel reinforcement cage is tied and cast.

[0040] In a preferred embodiment, a cement soil extended reinforcement section 5 composed of several plain cement soil piles is provided on the side of the combined pile foundation with large force. For example, as Figure 4 and 5 shown, when the upper part is a turning road, the load distribution will be greater on the outside than on the inside. At this time, several plain cement soil piles are cast and extended outward on the stressed side to form the cement soil extended reinforcement section 5 to meet the special bearing requirements of the upper part at extremely low cost.

[0041] The construction method of the variable stiffness pile-supported embankment structure includes the following steps:

[0042] First step, the cement soil mixer performs mixing construction according to the pile foundation positioning, and mixes out the cement soil outer core 11 of the rigid composite pile 1 and the pile type of the plain cement soil pile 2.

[0043] Second step, according to the design requirements, before the cement soil solidifies, the concrete inner core 12 is inserted into the rigid composite pile 1.

[0044] Third step, after the cement soil solidifies and the lower pile foundation meets the bearing requirements, the geotextile bags 3 are stacked on the upper part.

[0045] Fourth step, tie the steel bars of the bearing platform 4 on the geotextile bags 3 and cast.

[0046] Fifth step, after the concrete of the bearing platform 4 reaches the design strength requirement, it can bear the load of the upper road.

[0047] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "rear", etc. cited in the present invention are only for the convenience of clear description and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0048] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A variable stiffness pile-supported embankment structure based on rigid composite piles, characterized in that: It includes a number of rigid composite piles (1), a number of plain cement soil piles (2), a number of geotextile bags (3) and a bearing platform (4); The rigid composite pile (1) includes a cement soil outer core (11) and a concrete inner core (12) fixedly inserted into the cement soil outer core (11); A number of rigid composite piles (1) and a number of plain cement soil piles (2) are all inserted into the foundation; A number of geotextile bags (3) are stacked on the pile tops of a number of rigid composite piles (1) and a number of plain cement soil piles (2) to form a number of geotextile bag layers; The bearing platform (4) is fixed on the geotextile bag layer.

2. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 1, characterized in that: Among them, Among a number of rigid composite piles (1), every five rigid composite piles (1) are arranged to form a "cross" structure.

3. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 2, characterized in that: Among them, In the "cross" structure, the cement soil outer core (11) of the central rigid composite pile (1) coincides with the cement soil outer cores (11) of the surrounding rigid composite piles (1).

4. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 2, characterized in that: Among them, In the "cross" structure, the bottom of the cement soil outer core (11) of the central rigid composite pile (1) has a spherical cement expansion head (13).

5. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 2, characterized in that: Among them, A number of plain cement soil piles (2) connect a number of "cross" structures into a row of combined pile foundations; The variable stiffness pile-supported embankment structure includes a number of rows of combined pile foundations.

6. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 5, characterized in that: Among them, The plain cement soil pile (2) coincides with the cement soil outer core (11) of the adjacent rigid composite pile (1).

7. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 5, characterized in that: Among them, On the side of the combined pile foundation with large force, there is a cement soil extended reinforcement section (5) composed of a number of plain cement soil piles.

8. The variable stiffness pile-supported embankment structure based on rigid composite piles according to claim 1, characterized in that: Among them, The concrete pouring material of the concrete inner core (12) is a geopolymer cementitious material; The cement material of the cement soil outer core (11) is a geopolymer cementitious material.

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