CN1202557A

CN1202557A - Composite pile constructed in drilled hole

Info

Publication number: CN1202557A
Application number: CN 98114527
Authority: CN
Inventors: 梁仁旺; 巨玉艾; 崔江余
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-06-05
Filing date: 1998-06-05
Publication date: 1998-12-23

Abstract

The composite pile has the advantages of both friction pile and poured pile. The size of pile foundation is determined based on poured pile, there is one prefabricated reduced pile core at the center of pile foundation to provide the whole bearing force of pile, and the friction sleeve around the pile core is mixture of ballast and mortar. The composite pile is constructed through drilling, placing pile core, grouting, and filling ballast as well as stamping to densify and successive raising of buried pipe to ensure grouting pressure. It has easy-to-control quality, strengthened friction adhesion and improved comprehensive performance.

Description

Composite pile constructed in drilled hole

The invention belongs to the structure and the job practices of buildings pile, relate generally to the friction pile that is used for weak soil.

Known preformed pile bearing capacity height, reliable in quality; But produce very big noise in the construction, in the city, seldom adopt.Bored pile does not have soil compaction, the friction noise is little, is widely used in the city; But quality is wayward, and bearing capacity can not be given full play to, and stake top subsequent treatment workload is bigger.Composite pile is for overcoming some not enough class pile foundation that occurs of preformed pile and castinplace pile, existing different schemes proposes, enriched the job practices of pile foundation, become one of problem of being paid close attention to deeply this area, with regard to disclosed content finding, mostly made efforts in ambient influnence, raising intensity, reduction expense aspect, obtained progress, but also had some problems from reducing.As immersed tube bored prefabricating composite pile still have that a point is squeezed into, immersed tube and pile foundation be size-constrained in problems such as equipment.A scheme of increasing slave part for the stake lower end has strengthened the supporting capacity of stake end, but pile body and work progress change, and problem is existence still.The high-pressure rotary-spray composite pile has improved intensity, but material use is relatively poor, size is also restricted.

The objective of the invention is to propose more easily to bring into play the composite pile structure and the constructure scheme of bearing capacity and less expensive.

Structure division in the object of the invention is to realize like this, composite pile constructed in drilled hole comprises the different piece that is formed by prefabricated and site operation two class methods in the buildings pile, wherein prefabricated formed part is the stake core that is positioned at the composite pile shaft core position, and its size shape structure is by the decision that needs of bearing the whole load of pile foundation; The formed part of site operation is a friction sleeve, be distributed in around the prefabricated stake center, be that the mixture of graded broken stone and grouting, the conventional formulation that employing compressive strength is 2-6MPa are made, solidify bonding with the stake core by cement paste and link, and finally form the pile foundation profile; The overall dimensions of pile foundation is pressed the design principles decision of castinplace pile.Like this, prefabricated stake center can provide required axle center drag, sets up the required condition of work of friction pile through friction sleeve with all soil; Can keep the outside friction of castinplace pile by the size of castinplace pile decision and adhere to environment, rubble will be strengthened this rubbing action; Therefore the present invention can realize the function of same size weak soil friction pile with it fully, obviously also can obviously reduce corresponding cost simultaneously.Thereby the purpose of the relevant structure division of the present invention is achieved.

Pre-erection of the present invention is made up big and down small shape, the stress distribution situation when so meeting carrying.

The present invention also can be made into the prefabricated stake center that maybe can increase surperficial adhesion and frictional force shape than bigger serface, as stake core cross section be polygon, sawtooth ripple or other uneven shapes etc. are made in the surface.These also are the different measure that strengthens rubbing action.

Method in the object of the invention partly is to realize like this, the job practices of composite pile comprises makes and two major parts of site operation in advance, wherein, described what make in advance is the stake core of pile foundation, and described site operation carries out as follows: 1, make the hole suitable with the composite pile size on request in the pile foundation construction place in the precalculated position; 2, drop into the doubly rubble of the height in described aperture of 1.0-2.0 in the bottom, hole; 3, place prefabricated stake center at the hole shaft core position, in stake core surrounding space, make the mixture of rubble or graded broken stone and grouting routinely; 4, the cement paste natural coagulation reaches designing requirement intensity.Like this, drilling is the method that easily realizes, prefabricated stake core is inserted become comparatively simple, reduces construction cost; Cement paste can be set up the suitable intensity of recording part, and rubble can produce destruction to native surface light slip cream layer of hole wall week, helps improving the ability that produces rubbing action; The favourable intensity that improves stake end soil of rubble part at the bottom of the hole, these all are the methods that is of value to the performance of pile foundation supporting capacity and reduces whole cost, thereby the purpose of method part of the present invention is achieved.

The method of the invention is to replace pore-forming mud in the hole with cement paste before the rubble at the bottom of dropping into the hole, with formation and the quality that guarantees described mixture.

Rubble and graded broken stone all should be whole or tamping successively or shake close at the bottom of the hole described in the method for the invention, thereby can improve the intensity that improves mixture itself and all soil of pile foundation, strengthen rubble to the native surface light slip cream layer generation destruction of hole wall week, further improve the ability that pile foundation of the present invention produces rubbing action.

Should imbed Grouting Pipe in advance in the mixture configuration of graded broken stone described in the method for the invention part, promote gradually after waiting to reach the design grouting pressure, this also is a method of improving structural strength, makes the more closely knit unanimity of fine structure of grouting part, distributes rationally.

The present invention with prefabricated and the perfusion two kinds of pile foundations through particular combination, brought into play advantage separately preferably, and be aided with the improvement of structure, make effect comparatively remarkable.Construction quality of the present invention is easy to control, and the friction pile friction adhewsive action of capability development is according to this strengthened, and the cost of corresponding link decreases, and designs more reasonable science, and the combination property of composite pile of the present invention is improved.

Accompanying drawing has provided the aid illustration of embodiment of the invention structure and construction sequence signal.

Fig. 1 pore-forming, Fig. 2 are gone into cement paste, Fig. 3 from the hole rising pouring and are dropped into the rubble of the 1-2.0 times of aperture degree of depth at the bottom of the hole and hit reality, Fig. 4 preformed pile is inserted the rubble of drill center, Fig. 5 input grating toward the hole, the composite pile that Fig. 6 makes, and Fig. 7 is the A-A profile of Fig. 6.

Among the figure: 1, Grouting Pipe 2, cement paste 3, weight 4, rubble 5, stake core 6, friction sleeve 7, all soil of stake

The invention will be further described below in conjunction with embodiment.

First embodiment: design bearing capacity of single pile limiting value is the composite pile of 4104KN.

Continue to use the castinplace pile principle during design of this example, the stake footpath is designed to 800mm, the long 24m of stake.When adopting C35 prefabricated stake center 5, by the requirement of its Design of Bearing Capacity value k=4104/1.65=2487KN, stake core section area is 1600mm ², pile body axle power design load 2800KN was slightly larger than and required design load 2487KN this moment.Can reduce size by principle pile body hypomere of the present invention, so from pushing up the following 350 * 350=1225mm of use of 12m ²The cross section, this moment axle power design load 2143KN should meet the demands.

Construction sequence: 1, at the precalculated position pore-forming, aperture 800mm, dark 25m see Fig. 1.2, Grouting Pipe 1 is inserted at the bottom of the hole, injects the cement paste 2 for preparing, and with mud in its displacement hole, the cement paste volume is determined as calculated.At the bottom of the hole, drop into the thick rubble 4 of 1.0m then, see Fig. 2, Fig. 3.3, precast reinforced concrete piles core 5 is inserted in the middle of the hole, see Fig. 4.4, Xiang Kongzhong fills out rubble 4, hits reality while filling out, and up to the stake top, sees Fig. 5.5, the composite pile of making as shown in Figure 6.These routine materials: concrete 3.39m ³Rubble grouting body 8.61m ³

By this example as can be seen if press castinplace pile when enforcement, strength grade of concrete C20, to cross section is the pile body of diameter 800mm, its shaft center compression resistant Design of Bearing Capacity value should be fc * A=10000 * 0.503=5030KN., compare with the design load 2487KN that requires, the shaft center compression resistant bearing capacity of stake has only been brought into play less than 50%.The concrete amount of castinplace pile is 12m ³Obviously economical, reasonable not as this example.

Bearing capacity limiting value 4970KN is held in the design of the second embodiment single pile, still continues to use the castinplace pile design principles, and when adopting the C30 concrete, the prefabricated stake center cross section is 0.20m ², if select for use the square-section then to get 400 * 500mm ²Can meet the demands.

Construction sequence 1, in design attitude boring, aperture 1000mm, dark 25.4m.2, Grouting Pipe is inserted at the bottom of the hole.3, at the bottom of the hole, drop into the thick rubble of 1.0m, and hit reality with weight.4, prefabricated stake center is put into the center, hole.5, drop into the rubble that level prepares in the hole, the limit is thrown the rubble limit and is hit reality.6, after the degree of depth that Grouting Pipe is imbedded rubble surpasses 5.0m, beginning slip casting, rubble marginal not slurry is thrown on the limit, until a stake top mark height.These routine materials: concrete 4.88m ³, rubble grouting body 14.3m ³

This example is selected the stake core of square-section for use, can adapt to the relevant work condition, and the last example of rubbing action is strong slightly; Slip casting real is carried out synchronously with rockfilling, hit, and the total quality of pile foundation should be better than precedent.

The foundation soil of the 3rd embodiment is a silt, bearing capacity of single pile design load R=1588KN, design principles as above, but prefabricated stake center selects reinforced concrete pipe pile, stake footpath 550mm, wall thickness 100mm, the long 14m of stake, its Design of Bearing Capacity value 1700KN meets the demands.All the other the same substantially two examples, just material therefor is steel concrete 1.1m ³, rubble grouting body 5.1m ³, than cast-in-place pile concrete consumption 8.05m ³Obviously reduce.

Claims

1, composite pile constructed in drilled hole comprises in the buildings pile by different piece prefabricated and that site operation two class methods form, it is characterized in that: by prefabricated formed part is the stake core (5) that is positioned at the composite pile shaft core position, and its size shape structure determines routinely by the needs that bear the whole load of this pile foundation; The formed part of site operation is friction sleeve (6), be distributed in around the prefabricated stake center, be that graded broken stone (4) is made with the mixture of grouting (2), the conventional formulation that employing intensity is 2-6MPa, solidify bonding with the stake core by cement paste and link, and finally form the pile foundation profile; The overall dimensions of pile foundation is pressed the design principles decision of castinplace pile.

2, composite pile according to claim 1, it is characterized in that: described pre-erection is made up big and down small shape (5).

3, composite pile as claimed in claim 1 or 2, it is characterized in that: described pre-erection is made the prefabricated stake center (5) that maybe can increase surperficial adhesion and frictional force shape than bigger serface.

4, the job practices of the described composite pile of realization claim 1 comprises making and two major parts of site operation in advance, and it is characterized in that: described site operation carries out as follows

-make the hole suitable on request with the composite pile size in the pile foundation construction place in the precalculated position;

-drop into the doubly rubble of the height in described aperture of 1.0-2.0 in the bottom, hole;

-place prefabricated stake center at the hole shaft core position, in stake core surrounding space, make the mixture of rubble or graded broken stone and grouting routinely;

The natural coagulation of-cement paste reaches designing requirement intensity.

5, as job practices as described in the claim 4, it is characterized in that: drop at the bottom of the hole before the rubble with pore-forming mud in the cement paste displacement hole.

6, as job practices as described in claim 4 or 5, it is characterized in that: rubble and graded broken stone all should be whole or tamping successively or shake close at the bottom of the described hole.

7, as job practices as described in claim 4 or 5, it is characterized in that: should imbed Grouting Pipe (1) in advance in the mixture configuration of described graded broken stone part, promote gradually after waiting to reach the design grouting pressure.

8, as job practices as described in the claim 6, it is characterized in that: should imbed Grouting Pipe (1) in advance in the mixture configuration of described graded broken stone part, promote gradually after waiting to reach the design grouting pressure.