CN210341892U - Pressure-bearing pile and pile foundation applied to karst area - Google Patents

Abstract

The utility model relates to a be applied to bearing pile and pile foundation in karst area. The bearing pile comprises an outer cement mixing pile and a precast pile arranged in the cement mixing pile in a penetrating mode, and the cement mixing pile penetrates through a soil covering layer of the karst foundation and is abutted to the rock stratum. The pressure-bearing pile takes the precast pile as the pile core, and the strength of the pressure-bearing pile is enhanced. Thereby can increase the stake footpath of bearing-pressure stake through lower cost with cement mixing stake as the skin, and then increase the side friction of bearing-pressure stake and karst foundation, further improved the bearing capacity of bearing-pressure stake.

Description

Pressure-bearing pile and pile foundation applied to karst area

Technical Field

The utility model relates to a civil engineering technical field especially relates to a be applied to bearing pile and pile foundation in karst area.

Background

At present, the types of engineering pressure-bearing piles can be divided into precast piles and precast piles according to different construction methods and structures. In the karst area, the upper soil layer is loose due to large burial depth of the karst, and sinking or collapse is easy to occur under the load action of the building, so that the safety of the building is endangered. Therefore, the bearing capacity of the bearing pile in the karst foundation is high. Usually, the length and diameter of a bearing pile in a karst foundation need to be designed to be large so as to meet the bearing requirement. But large and long precast piles are not only difficult and uneconomical to implant.

SUMMERY OF THE UTILITY MODEL

Therefore, a bearing pile and a pile foundation applied to a karst area are needed to be provided aiming at the problem of how to effectively improve the bearing capacity of the bearing pile.

The utility model provides a be applied to karst area's bearing pile, bearing pile includes outer cement mixing stake and wears to establish the precast pile in the cement mixing stake, the precast pile is hollow tubular pile, cement mixing stake be used for pass karst ground cover soil layer and with the stratum butt of cover soil layer below.

Above-mentioned bearing pile regards precast pile as the stake core, and the precast pile is implanted construction convenience, and the time limit for a project is short to the quality is reliable, and the precast pile has strengthened the intensity of bearing pile. Furthermore, the bearing pile takes the cement mixing pile as an outer layer, and the cement mixing pile is low in manufacturing cost, so that the pile diameter of the bearing pile can be increased through low cost, the side friction force between the bearing pile and the karst foundation is increased, and the bearing capacity of the bearing pile is improved. And the cement mixing pile extends to a firmer rock stratum in a karst area, and the rock stratum is used as a bearing layer of the bearing pile, so that the bearing capacity of the bearing pile is further improved, and the problems of sinking and collapse of a soil covering layer due to the fact that the soil covering layer cannot bear the load are effectively solved.

In one embodiment, the precast pile comprises a plurality of sub-piles, joints are arranged at two ends of each sub-pile, and the plurality of sub-piles are sequentially connected in the axial direction through the joints.

In one embodiment, the joint is a connecting flange, and two adjacent sections of the sub-piles are connected through the connecting flange; or the joints are embedded steel plates, and the two adjacent sections of the sub-piles are connected in a welding mode.

In one embodiment, the precast pile is a prestressed pipe pile.

In one embodiment, the axial length of the precast pile is greater than the axial length of the cement mixing pile, and the precast pile protrudes into the rock formation.

In one embodiment, a cavity is arranged in the upper part of the cement mixing pile, the precast pile is arranged in the cavity, and the lower part of the cement mixing pile is a solid column.

In one embodiment, the diameter of the cement mixing pile is 1000mm-2000mm, the axial length of the cement mixing pile is 5m-30m, the cement admixture ratio of the cement mixing pile is 12% -18%, and the water cement ratio is 0.5-1.5.

The utility model provides a pile foundation, includes the cushion cap and a plurality of foretell bearing pile, the cushion cap set up in bearing pile top is used for connecting a plurality of bearing pile.

The pile foundation adopts the precast pile as the pile core and the cement mixing pile as the outer composite pressure-bearing pile, thereby effectively improving the pressure-bearing capacity of the pile foundation, reducing the length of the pressure-bearing pile and reducing the construction cost and the construction difficulty.

In one embodiment, a gravel cushion layer is further arranged at the bottom of the bearing platform.

In one embodiment, the thickness of the gravel cushion is 50cm-70 cm.

In one embodiment, a plurality of bearing piles are uniformly distributed on the bearing platform.

Drawings

Fig. 1 is a schematic longitudinal sectional structure of a pressure-bearing pile according to an embodiment;

fig. 2 is a schematic longitudinal sectional structure of a pressure-bearing pile according to another embodiment;

fig. 3 is a schematic structural view of a precast pile according to an embodiment;

fig. 4 is a schematic structural view of a precast pile according to another embodiment;

FIG. 5 is a schematic top view of a pile foundation according to an embodiment;

fig. 6 is a sectional view of the pile shown in fig. 5 taken along the line a-a.

Wherein:

100. bearing piles; 110. Stirring the piles with cement; 111. A cavity;

120. prefabricating a pile; 121. Sub-piles; 122. A joint;

123. connecting angle steel; 200. Karst foundation; 210. A rock formation;

220. covering a soil layer; 221. The clay layer 222 is filled with a sand layer;

300. a pile foundation; 310. A bearing platform; 320. And (5) a gravel cushion layer.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention can be embodied in many different forms other than those specifically described herein, and it will be apparent to those skilled in the art that similar modifications can be made without departing from the spirit and scope of the invention, and it is therefore not to be limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the present embodiment provides a pressure-bearing pile 100, which can be applied to a karst foundation 200. Specifically, the lower layer of the karst foundation 200 is a rock stratum 210, and the rock stratum 210 is covered with a soil covering layer 220. The cover layer 220 is mostly an unstable and collapsible structure, and the cover layer 220 further includes a clay layer 221 and a sand filling layer 222 covering the clay layer 221.

Specifically, the pressure-bearing pile 100 includes a precast pile disposed in an outer layer of a cement mixing pile 110 penetrating inside the cement mixing pile 110. The precast pile 120 is a concrete hollow pipe pile prepared in advance in a prefabrication plant. The precast pile 120 serves as a core of the pressure bearing pile 100. The cement mixing pile 110 is formed by injecting cement into the soil covering layer 220 by using a mixing pile machine as a main agent of a curing agent and fully mixing the cement, so that the cement and clay in the soil covering layer 220 generate a series of physical and chemical reactions to harden the clay to form a high-strength pile body. Further, the cement mixing pile 110 penetrates the soft overburden 220 and abuts the stronger formation 210. The cement mixing pile 110 can thus be a holding formation with the formation 210, dispersing the load through the formation 210.

The construction steps of the pressure-bearing pile 100 are as follows: firstly, according to the structural design requirement, cement is sprayed into the soil covering layer 220 by using a mixing pile machine and is fully mixed to form the cement mixing pile 110. And then the precast pile 120 is implanted into the cement mixing pile 110 within 12 hours before the cement soil is solidified, wherein the implantation mode of the precast pile 120 is a hammering method, a vibration method, a static pressure method and the like.

The pressure-bearing pile 100 uses the precast pile 120 as a pile core, the precast pile 120 is convenient to implant and construct, the construction period is short, and the precast pile 120 with reliable quality enhances the strength of the pressure-bearing pile 100. Further, the bearing pile 100 uses the cement mixing pile 110 as an outer layer, and the cement mixing pile 110 has low manufacturing cost, so that the pile diameter of the bearing pile 100 can be increased through low cost, the side friction force between the bearing pile 100 and the karst foundation 200 is increased, and the bearing capacity of the bearing pile 100 is improved. And the cement mixing pile 110 extends to the firmer rock stratum 210 in the karst foundation 200, and the rock stratum 210 is used as the bearing layer of the bearing pile 100, so that the bearing capacity of the bearing pile 100 is further improved, and the problems of sinking and collapse of the soil covering layer 220 caused by the fact that the bearing layer cannot bear the load are effectively prevented.

With continued reference to fig. 1, in the karst foundation 200 where the overburden 220 is relatively shallow, the axial length of the precast pile 120 is greater than the axial length of the cement mixing pile 110, and the precast pile 120 protrudes into the rock stratum 210. Since the formation of the cement mixing pile 110 requires the clay of the overburden 220 to participate, the length of the cement mixing pile 110 formed in the relatively shallow karst ground of the overburden 220 is limited, and the load-bearing capacity of the pressure-bearing pile can be enhanced by extending the precast pile 120 into the rock stratum 210.

Referring to fig. 2, in another embodiment, in the karst foundation 200 where the overburden 220 is relatively deep, a cavity 111 is provided in an upper portion of the cement mixing pile 110, a precast pile 120 is provided in the cavity 111, and a lower portion of the cement mixing pile 110 is a solid cylinder. That is, the axial length of the precast pile 120 is less than or equal to the axial length of the cement mixing pile 110. In the karst foundation 200 with the relatively deep soil covering layer 220, the axial length of the cement mixing pile 110 can be ensured, the manufacturing cost of the cement mixing pile 110 is lower than that of the precast pile 120, and the cement mixing pile 110 is designed to be longer than that of the precast pile 120, so that the bearing capacity of the bearing pile 100 can be improved, and meanwhile, the cost can be saved.

Referring to fig. 3 and 4, in one embodiment, the precast pile 120 includes multiple sub-piles 121, and the multiple sub-piles 121 may be connected in sequence to form a precast pile 120 with a desired length according to structural design requirements. Specifically, joints 122 are provided at both ends of the sub-piles 121, and the multi-sectional sub-piles 121 are sequentially connected in the axial direction by the joints 122. Further, referring to fig. 3, the joint 122 of the sub-pile 121 is a connecting flange, and two adjacent sections of the sub-pile 121 are connected by the connecting flange. In another embodiment, referring to fig. 4, the joints 122 of the sub-piles 121 are embedded steel plates, and two adjacent sub-piles 121 are connected by welding through connecting angle steels 123.

In one embodiment, the precast pile 120 is coaxially disposed with the cement mixing pile 110. The pipe diameter and the pile length of the precast pile 120 need to be calculated and confirmed according to the bearing requirement. Further, the precast pile 120 is a prestressed pipe pile. The prestressed pipe pile has high bearing capacity and multiple selectable specifications, and can meet various karst terrain requirements.

In one embodiment, the diameter of the cement mixing pile 110 is 1000mm-2000mm, and the axial length of the cement mixing pile 110 is 5m-30 m. Further, the curing agent used in the cement mixing pile 110 is portland cement having a strength grade of 42.5 or more. The cement ratio is 12-18%, namely the cement mixing amount is 12-18% of the mass of the reinforced soft soil. The water cement ratio is 0.5-1.5, namely the ratio of the water consumption in the cement paste to the cement consumption is 0.5-1.5.

Referring to fig. 5 and 6, the present invention further provides a pile foundation 300 for a karst area, including a cap 310 and a plurality of pressure-bearing piles 100 according to any one of the above embodiments. Specifically, the cap 310 is a reinforced concrete structure, and the cap 310 is disposed on the top of the pressure-bearing pile 100. And the cap 310 connects the plurality of pressure-bearing piles 100 such that the cap 310 is formed as one body with the pressure-bearing piles 100. The cap 310 is used to bear and disperse the load on the pile foundation 300. Further, a plurality of pressure-bearing piles 100 are uniformly distributed on the platform 310, for example, as shown in fig. 5, the pile foundation 300 includes 5 pressure-bearing piles 100, and the 5 pressure-bearing piles 100 are respectively disposed at the center of the ground of the platform 310 and at 4 angular positions of the platform 310, so that the load can be more uniformly dispersed.

Further, a gravel cushion layer 320 is arranged at the bottom of the bearing platform 310, and the thickness of the gravel cushion layer 320 is 50cm-70 cm. The gravel pack 320 is used to pave the foundation 200 to facilitate better construction of the cap 310.

The construction steps of the pile foundation 300 are as follows:

and S1, spraying cement into the soil covering layer 200 by using a mixing pile machine according to the structural design requirement and fully mixing to form the cement mixing pile 110.

And S2, implanting the precast pile 120 into the cement mixing pile 110 within 12 hours before the cement soil is solidified, wherein the implantation mode of the precast pile 120 is a hammering method, a vibration method, a static pressure method and the like.

And S3, paving and compacting the pile caps of the pressure-bearing piles 100 by using broken stones to form broken stone cushions 320.

S4: a cap 310 is constructed on the crushed stone pad 320.

The pile foundation 300 adopts the composite pressure-bearing pile 100 which takes the precast pile 120 as a pile core and the cement mixing pile 110 as an outer layer, thereby effectively improving the pressure-bearing capacity of the pile foundation 300, reducing the length of the pressure-bearing pile 100 and reducing the construction cost and the construction difficulty.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. The utility model provides a be applied to karst area's bearing pile, its characterized in that, bearing pile includes outer cement mixing stake and wears to establish the precast pile in the cement mixing stake, the precast pile is hollow tubular pile, cement mixing stake be used for pass karst ground the overburden layer and with the stratum butt of overburden layer below.

2. A pressure-bearing pile for karst areas according to claim 1, wherein the precast pile comprises a plurality of sub-piles, joints are arranged at two ends of the sub-piles, and the plurality of sub-piles are sequentially connected in the axial direction through the joints.

3. A pressure-bearing pile for karst areas according to claim 2, wherein the joint is a connecting flange, and two adjacent sections of the sub-pile are connected through the connecting flange; or the joints are embedded steel plates, and the two adjacent sections of the sub-piles are connected in a welding mode.

4. A pressure-bearing pile for karst areas according to claim 1, wherein the precast pile is a prestressed pipe pile.

5. A pressure-bearing pile for use in karst areas according to claim 1, characterised in that the axial length of the pre-pile is greater than the axial length of the cement mixing pile and the pre-pile protrudes into the rock formation.

6. A pressure-bearing pile applied to a karst area according to claim 1, wherein a cavity is arranged in the upper part of the cement mixing pile, the precast pile is arranged in the cavity, and the lower part of the cement mixing pile is a solid cylinder.

7. A pressure-bearing pile for karst areas according to claim 1, wherein the cement mixing pile has a diameter of 1000mm to 2000mm and an axial length of 5m to 30 m.

8. A pile foundation comprising a bearing platform and a plurality of bearing piles applied to a karst area according to any one of claims 1 to 7, wherein the bearing platform is provided on the top of the bearing piles to connect the plurality of bearing piles.

9. The pile foundation of claim 8, wherein the cap bottom is further provided with a gravel cushion.

10. The piling of claim 9, wherein said gravel pack has a thickness of 50cm to 70 cm.

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