CN202500145U - Pile foundation of micro pile group - Google Patents

Abstract

The utility model discloses a pile group foundation of miniature piles, which comprises: a tower foundation cap, a first miniature pile, a plurality of anchor bolts and a plurality of second miniature piles; the first miniature pile includes: a longitudinally coaxially connected miniature A pile expansion head and a micro-pile straight column, the micro-pile expansion head is coaxially arranged at the bottom of the foundation cap of the tower, first reinforcements are respectively arranged in the micro-pile expansion head and the micro-pile straight column, and the first reinforcement extends into In the tower foundation cap; one end of each of the anchor bolts passes through the tower foundation cap and extends into the micro pile expansion head, and the other end exposes the top of the tower foundation cap; the plurality of The second micro piles are respectively arranged at the bottom of the foundation cap of the tower, and are arranged symmetrically with the first micro pile as the center; second reinforcement is arranged in each of the second micro piles, and the second The reinforcement extends into the foundation cap of the tower. The utility model improves the convenience of the foundation construction of micro-pile group piles.

Description

Micropile Group Pile Foundation

technical field

The utility model relates to the engineering technology of transmission lines, in particular to a pile group foundation of miniature piles.

Background technique

The tower foundation is used to provide load support for the transmission line tower, and is an important part of the transmission line engineering structure. Micropile group pile foundation is a form of tower foundation for transmission line engineering, which is mainly used in loess foundation with deep water table and similar geological environments.

Fig. 1 is a structural schematic diagram of a pile group foundation of miniature piles provided by the prior art. As shown in Figure 1, the existing micro-pile group pile foundation includes: anchor bolts 11, tower foundation columns 12, tower foundation caps 13 and micro piles 14; one end of the anchor bolts 11 is embedded in the tower foundation columns 12 and extends into the The other end of the tower foundation cap 13 exposes the top of the tower foundation column 12; and the anchor bolts 11, the tower foundation column 12, the tower foundation cap 13 and the micro-pile 14 are formed by integral casting of concrete.

In the above-mentioned prior art, in order to meet the requirement of the specific anchoring length of the anchor bolts, the tower foundation column needs to reach a certain height (usually 1m-3m), which inevitably increases the bottom plate depth of the tower foundation cap. In the process of making the foundation cap of the pole tower, it is necessary to excavate the foundation pit of the cap first, and after completing the construction of the foundation cap of the pole tower, backfill earthwork in the foundation pit. The greater the depth of the bottom plate of the tower foundation cap, the greater the amount of earthwork excavation and backfilling required during the construction of the tower foundation, which increases the construction workload and causes more serious damage to the environment.

Utility model content

The utility model provides a pile group foundation of miniature piles, which is used to improve the convenience of construction and reduce the damage to the environment caused by the construction of pole tower foundations.

The utility model provides a pile group foundation of miniature piles, comprising:

Tower foundation cap, first micro pile, multiple anchor bolts and multiple second micro piles;

The first micro-pile includes: a micro-pile expansion head and a micro-pile straight column coaxially connected longitudinally, the micro-pile expansion head is coaxially arranged at the bottom of the tower foundation cap, the micro-pile expansion head and the micro-pile First reinforcements are respectively arranged in the straight columns, and the first reinforcements extend into the foundation cap of the tower;

One end of each of the anchor bolts passes through the tower foundation cap and extends into the micropile expansion head, and the other end exposes the top of the tower foundation cap;

The plurality of second micropiles are respectively arranged at the bottom of the foundation cap of the tower, and are arranged symmetrically with the first micropiles as the center; second reinforcement is arranged in each of the second micropiles, and The second reinforcement extends into the foundation cap of the tower.

Optionally, the tower foundation cap, the first micro pile, the plurality of anchor bolts and the plurality of second micro piles are formed by integral casting of concrete.

Optionally, the plurality of anchor bolts are arranged symmetrically about the longitudinal central axis of the foundation cap of the tower. The distance between each of the anchor bolts and the longitudinal central axis of the tower foundation cap is greater than the radius of the micro-pile straight column and smaller than the radius of the micro-pile enlarged head. The diameter of the straight column of the micro-pile is 25cm-40cm, and the diameter of the enlarged head of the micro-pile is 60cm-120cm. The first micropile and the second micropile are equal in length, and the length is 4m-10m. The length of the enlarged head of the micro pile is 1m-2m. The part where the anchor bolts extend into the enlarged head of the miniature pile has a length of 80cm-150cm.

Optionally, the length of the first reinforcement and/or the second reinforcement extending into the foundation cap of the tower is greater than or equal to 40 times the diameter of the reinforcement. The distance between the longitudinal central axis of the second micro-pile and the longitudinal central axis of the first micro-pile is greater than or equal to 2.5 times the diameter of the second micro-pile.

In the micro pile group foundation provided by the utility model, the head of the first micro pile coaxially arranged longitudinally with the tower foundation cap is set as a micro pile expansion head, and one end of the anchor bolt is passed through the tower foundation cap and Stretch into the enlarged head of the micro-piles, so that the embedment depth of the anchor bolts can meet the anchorage length requirements. Since the micro-pile group pile foundation of the utility model meets the anchoring length requirements of the anchor bolts, there is no need to set up columns on the top of the tower foundation cap, thereby reducing the bottom plate depth of the tower foundation cap, thereby reducing the construction process of the tower foundation. The amount of earthwork excavation and backfill earthwork required in the process improves the convenience of construction, and further reduces the damage to the environment caused by the construction of the tower foundation.

Description of drawings

Fig. 1 is the structural representation of the miniature pile group pile foundation that prior art provides;

Fig. 2 is the sectional structure schematic diagram of the miniature pile group pile foundation that the utility model provides;

Fig. 3 is the schematic diagram of the top view structure of the micro-pile group pile foundation provided by the utility model;

Fig. 4 a is the construction example plan view of the micropile hole provided by the utility model;

Fig. 4 b is the construction example plan view of excavating the micropile enlarged head hole on 4a;

Fig. 4c is a plan view of a construction example of excavating a tower foundation cap hole on 4b;

Figure 4d is a plan view of a construction example of arranging reinforcement and anchor bolts on 4c;

Fig. 4e is a plan view of a construction example of pouring concrete integrally formed on 4d.

Reference signs:

21- tower foundation cap; 22- the first micro pile; 23- anchor bolts;

24-the second miniature pile; 221-miniature pile expansion head; 222-miniature pile straight column;

223-the first reinforcement; 241-the second reinforcement; 3-miniature pile holes;

4- Micropile expansion head hole; 5- Tower foundation cap hole; 6- Concrete.

Detailed ways

Fig. 2 is a schematic cross-sectional structure diagram of the micro-pile group pile foundation provided by the utility model. The micro pile group foundation shown in FIG. 2 includes: a tower foundation cap 21 , a first micro pile 22 , a plurality of anchor bolts 23 and a plurality of second micro piles 24 .

The first micro-pile 22 comprises: a micro-pile enlargement head 221 and a micro-pile straight post 222 connected longitudinally and coaxially; First reinforcing bars 223 are respectively arranged in 222 , and the first reinforcing bars 223 extend into the tower foundation cap 21 .

One end of each anchor bolt 23 passes through the tower foundation cap 21 and stretches into the micro-pile enlarged head 221, and the other end exposes the top of the tower foundation cap 21 for being connected with the tower legs of the power transmission line tower on the ground.

A plurality of second micro piles 24 are respectively arranged at the bottom of the tower foundation cap 21, and are arranged symmetrically with the first micro pile 22 as the center; each second micro pile 24 is arranged with a second reinforcement 241, and the second distribution The ribs 241 extend into the foundation cap 21 of the tower.

In the micro pile group foundation provided by the utility model, the head of the first micro pile coaxially arranged longitudinally with the tower foundation cap is set as a micro pile expansion head, and one end of the anchor bolt is passed through the tower foundation cap and Stretch into the enlarged head of the micro-piles, so that the embedment depth of the anchor bolts can meet the anchorage length requirements. Since the micro-pile group pile foundation of the utility model meets the anchoring length requirements of the anchor bolts, there is no need to set up columns on the top of the tower foundation cap, thereby reducing the bottom plate depth of the tower foundation cap, thereby reducing the construction process of the tower foundation. The amount of earthwork excavation and backfill earthwork required in the process improves the convenience of construction, and further reduces the damage to the environment caused by the construction of the tower foundation.

On the basis of the above technical solution, optionally, the tower foundation cap 21, the first micro-pile 22, multiple anchor bolts 23 and multiple second micro-piles 24 can be formed by integral casting of concrete.

In order to facilitate the connection of the anchor bolts to the tower legs of the upper power transmission line, optionally, a plurality of anchor bolts 23 are arranged symmetrically about the longitudinal central axis of the foundation cap 21 of the tower. As shown in FIG. 3 , the number of anchor bolts may be four, and the four anchor bolts are arranged in a square symmetrical to the longitudinal central axis of the tower foundation cap 21 . The distance between each anchor bolt and the longitudinal central axis of the tower foundation cap can be greater than the radius of the micro-pile straight column and smaller than the radius of the micro-pile enlarged head, so as to improve the convenience of construction and better meet Anchor bolt anchoring requirements. An optional implementation is for example: the first micro-pile and the second micro-pile are equal in length, and the length is 4m-10m; in the first micro-pile, the diameter of the straight column of the micro-pile is 25cm-40cm, and the diameter of the micro-pile is 25cm-40cm. The diameter of the expanding head is 60cm-120cm; the length of the expanding head of the micro-pile is 1m-2m; the part where the anchor bolts extend into the expanding head of the micro-pile has a length of 80cm-150cm; and so on. Further optionally, the distance between the longitudinal central axis of the second micro-pile and the longitudinal central axis of the first micro-pile is greater than or equal to 2.5 times the diameter of the second micro-pile, so that each micro-pile can Evenly share the load transmitted by the tower foundation cap, thereby improving the overall stability and bearing capacity of the micro-pile group pile foundation.

In order to improve the strength of the connection between the tower foundation cap and the micro-pile, the length of the reinforcement arranged in each micro-pile extending into the tower foundation cap can be flexibly determined according to the rules of reinforcement. For example: the length of the first reinforcement and/or the second reinforcement extending into the foundation cap of the tower is greater than or equal to 40 times the diameter of the reinforcement.

In the above technical solution, the total number of micro-piles, that is, the total number of the first micro-piles and the second micro-piles can be 9, and the 9 micro-piles are arranged in a 3×3 square array, and the longitudinal central axis of the tower foundation cap The first micro-piles are coaxial, and eight second micro-piles are arranged symmetrically with the first micro-piles as the center. An example of the arrangement is shown in Figure 3. Apparently, the utility model also supports various arrays of micropile forms such as 5×5 and 7×7, which will not be repeated here.

Taking the micro-pile group pile foundation arranged in a 3×3 square array as an example below, an example of an optional construction method for the micro-pile group pile foundation of the present utility model is illustrated. The specific construction methods include:

Step 1: Excavate 9 micropile holes 3 with a medium diameter in the foundation, and the 9 micropile holes 3 are arranged in a 3×3 square array; the plan view of the construction example is shown in Figure 4a.

Step 2: Excavate the upper part of the micropile hole located in the middle of the square array into the micropile expansion head hole 4; the plan view of the construction example is shown in Figure 4b.

Step 3: Excavate the upper part of each micropile hole and the micropile enlarged head hole to form the tower foundation cap hole 5; the plan view of the construction example is shown in Figure 4c.

Step 4: Arrange reinforcements in each micropile hole and micropile expansion head, such as the second reinforcement 241 or the first reinforcement 223, etc., and one end of each reinforcement extends into the hole of the tower foundation cap; Four anchor bolts 23 are arranged squarely and symmetrically on the longitudinal center axis; one end of each anchor bolt 23 passes through the hole of the tower foundation cap and extends into the hole of the micro pile expansion head, and the other end exposes the top of the hole of the tower foundation cap; construction example The plan view of is shown in Fig. 4d.

Step 5: pouring concrete 6 into one piece, the plan view of the construction example is shown in Figure 4e, and the construction of the micro pile group foundation is completed so far.

The micro-pile group pile foundation provided by the utility model does not need to separately set up tower foundation columns for anchoring the anchor bolts, and the force on the foundation bolts can be directly transmitted to each micro-pile through the pole-tower foundation cap, and the load is shared by each micro-pile . The bending moment on the top of each micropile satisfies the following formula:

M=F×h (1)

In the above formula (1), M represents the bending moment on the top of the micro-pile; F represents the external force along the horizontal direction, that is, the horizontal force; h represents the distance between the acting surface of the horizontal force and the top of the micro-pile. Since the utility model omits the column of the pole tower foundation, h is smaller than the distance between the surface of the horizontal force of the existing micro-pile group pile foundation and the top of the micro-pile. Therefore, under the same horizontal force load, the utility model Compared with the prior art, the bending moment borne by each micro pile is reduced. The smaller the bending moment of the micro-pile, the smaller the size of the micro-pile can be made, such as adopting a smaller diameter of the micro-pile and a shorter length of the micro-pile. It can be seen that, on the basis of realizing the above-mentioned technical effects, the utility model is also beneficial to saving micropile consumables and reducing the workload required for micropile construction.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present utility model, and are not intended to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit of the technical solutions of the various embodiments of the present invention. and range.

Claims (10)

1. A micropile pile group foundation, characterized in that, comprising: Tower foundation cap, first micro pile, multiple anchor bolts and multiple second micro piles; The first micro-pile includes: a micro-pile expansion head and a micro-pile straight column coaxially connected longitudinally, the micro-pile expansion head is coaxially arranged at the bottom of the tower foundation cap, the micro-pile expansion head and the micro-pile First reinforcements are respectively arranged in the straight columns, and the first reinforcements extend into the foundation cap of the tower; One end of each of the anchor bolts passes through the tower foundation cap and extends into the micropile expansion head, and the other end exposes the top of the tower foundation cap; The plurality of second micropiles are respectively arranged at the bottom of the foundation cap of the tower, and are arranged symmetrically with the first micropiles as the center; second reinforcement is arranged in each of the second micropiles, and The second reinforcement extends into the foundation cap of the tower. 2. The micropile group pile foundation according to claim 1, characterized in that, the tower foundation cap, the first micropiles, the plurality of anchor bolts and the plurality of second micropiles, Formed by pouring concrete in one piece. 3. The micro-pile group pile foundation according to claim 1, wherein the plurality of anchor bolts are arranged symmetrically about the longitudinal center axis of the tower foundation cap. 4. The micropile group pile foundation according to claim 3, wherein the distance between each of the anchor bolts and the longitudinal central axis of the tower foundation cap is greater than the radius of the micropile straight column and less than The micropiles expand the radius of the head. 5. The micropile group foundation according to any one of claims 1-4, characterized in that, the diameter of the straight post of the micropile is 25cm-40cm, and the diameter of the enlarged head of the micropile is 60cm-120cm. 6. The pile group foundation according to claim 5, characterized in that, the first micropile and the second micropile are equal in length, and the length is 4m-10m. 7. The pile group foundation of micropile according to claim 6, characterized in that, the length of the enlarged head of the micropile is 1m-2m. 8. The micro-pile group pile foundation according to claim 7, wherein the anchor bolts extend into the part of the enlarged head of the micro-pile, and the length is 80cm-150cm. 9. The micro pile group foundation according to any one of claims 1-4, characterized in that, the length of the first reinforcement and/or the second reinforcement extending into the cap of the tower foundation is greater than Or equal to 40 times the diameter of the reinforcement. 10. The pile group foundation according to any one of claims 1-4, characterized in that, the distance between the longitudinal central axis of the second micropile and the longitudinal central axis of the first micropile is greater than or equal to 2.5 times the diameter of the second micropile.

Images