Background technology
At present in the very large Hong Kong of pile foundation usage ratio, socketed pile all is as the pile body bearing carrier with heavy steel H pile, on-the-spot between stake and hole wall, pour into cement paste as soil layer in pile body antirust and transmit and transmit vertical force in horizontal force, the petrosal foramen, because the cement paste that wraps in the pile body outside may suffer the influence of underground water or bad soil property before sclerosis, necking down even fracture take place easily, its pile serviceability rate can not be subjected to thorough guarantee, usually do not consider as vertical bearing carrier, except that bending rigidity is low, can not makes the best use of everything and cause bigger waste.Though some prebored hole combined rock-embedding pile based on prefabricated concrete pipe pile has increased substantially vertical bearing capacity, but still do not relate to the horizontal bearing capacity problem less than normal that how to solve, and only to add reinforcing bar at the prefabricated concrete pipe pile center to improve vertical bearing capacity be cost, working procedure is loaded down with trivial details, so cost is still higher.Once used prefabricated steel pipe concrete pipe pile also just to design and produce as the impacting type job practices in Hong Kong, because of it is a hollow shell pill, steel pipe is to concrete effect of contraction and not obvious, so bearing capacity of concrete-filled wherein remains according to common pressurized concrete column computational methods and calculates, its cost performance does not have significant advantage, therefore is not extensive use of on the construction market of Hong Kong.The socketed pile type of the permanent steel pipe of another kind of use is exactly mini pile (MINI PILE), but its bearing capacity is to be provided by the major diameter tendon in the steel pipe, since steel pipe and rock stratum there is no reliable be connected and steel content too high, steel pipe and cement paste wherein just play antirust, positioning action to above-mentioned reinforcing bar, do not consider its bearing capacity, its cost is positioned at the umber one in existing stake type, so be not the requirement of particular surroundings, generally can not adopt.
The patent of invention content
The objective of the invention is various defectives at the existence of above-mentioned existing stake type, in conjunction with the present domestic superior structural characteristic that generally is used for the steel core concrete column of superstructure, propose a kind of steel-pipe concrete assembled pile of predrilled hole rock-embedded structure, fill up the blank of concrete filled steel tubular member in the socketed pile base application according to this.It can make the boring socketed pile make simple, integrated cost reduces, applied widely, pile body resistance to compression, bending resistance shearing resistance and antitorque bearing capacity height, rigidity is big, the construction period is short and pile quality is reliable, and bearing capacity and all interior constructional materials intensity of pile body that petrosal foramen can be provided are fully utilized.
To achieve these goals, the invention provides a kind of steel-pipe concrete assembled pile of predrilled hole rock-embedded, described embedding rock concrete filled steel tube compound pile comprises the packing material between preboring soil hole and the steel tube concrete pile or the steel tube concrete pile in the continuity preboring petrosal foramen in its lower section of inserting below the face of land and the shaped steel that is connected its bottom or combination steel member or reinforcing cage or precast reinforced concrete structure or their combination and stake and the prebored hole; Described steel tube concrete pile all in-situ casting becomes or all prefabricated or half prefabricated half cast-in-place making.
Described concrete filled steel tube compound pile comprises steel pipe shell and the concrete or the steel concrete that are wrapped in by steel pipe: when the steel pipe inner concrete is pure when cast-in-place, whole stake bottom is the continuity of above-mentioned steel tube concrete pile; When the steel pipe inner concrete is prefabricated or half prefabricated half when cast-in-place, the packing material that whole stake bottom adopts steel tube concrete pile or shaped steel or reinforcing cage or precast reinforced concrete structure or their combination and later stage to build.
Steel tube concrete pile can be by factory's prefabricate or half prefabricated, also can be formed to inserting steel pipe in the prebored hole or steel pipe concrete pipe pile inner chamber concreting or steel concrete or steel reinforced concrete by the scene.
Described steel pipe shell is various seamless steel pipes or welded steel pipe, steel pipe inner face or outside or inside and outside two sides can be equipped with the steel member of longitudinal reinforcement or reinforcing cage or stirrup or opposing longitudinal shear or twine the charcoal fabric, in the steel pipe or external surface or two-sided spary as required is antirust or improve the coating of adhesion stress, be provided with or tube wall be not set in the steel pipe to socket the steel member; When steel pipe outside when reinforcing cage is installed only, then the steel tube concrete pile part can adopt complete prefabricated or half prefabricated half cast-in-place form of structure, also can directly adopt the fished pipe concrete tubular pile to replace the form of structure of steel pipe, the bottom of steel tube concrete pile is opened or is sealed with steel plate.
Described concrete filled steel tube compound pile can be that whole stake or multistage are prefabricated, described multistage stake by stake end steel plate or additional welding, bonding, the bolt that connects between the steel plate connect, latch connects, snap close connects or sleeve connects or being connected together by its Men; The shaped steel of concrete filled steel tube compound pile bottom or combination steel member or reinforcing cage or precast reinforced concrete structure by additional steel plate be connected with the welding of stake end steel plate, bonding, the bolt of the steel tube concrete pile on top, latch connects, snap close connects or sleeve connection or being connected together by them.
Concrete in the described steel tube concrete pile or steel concrete are at the construction field (site) steel pipe to be inserted in the prebored hole earlier, and whole then stake concreting or steel concrete form; Perhaps replace steel pipe by the steel pipe segmentation with the superimposed finished product prefabricated concrete pipe pile of prestressed concrete pipe pile that comprises of caking property packing material earlier, insert in the prebored hole then; Or at the scene steel pipe is inserted in the prebored hole earlier, insert the finished product prefabricated concrete pipe pile that comprises prestressed concrete pipe pile then continuously than minor diameter, above-mentioned finished product prefabricated concrete pipe pile inner chamber in-site pouring concrete or steel concrete or steel reinforced concrete, the gap between above-mentioned finished product prefabricated concrete pipe pile and the steel pipe pour into the caking property packing material and form the multilayer build-up steel tube concrete pile.
Described steel tube concrete pile is that factory's prefabricate forms, and perhaps adopts the fished pipe concrete tubular pile to replace the steel pipe shell, then at fished pipe concrete tubular pile inner chamber in-site pouring concrete or steel concrete or steel reinforced concrete.
Described steel-pipe concrete assembled pile of predrilled hole rock-embedded pile crown can adopt various usual manners with being connected of pile cap, for example free pile crown or hinged pile crown or slide hinged pile crown or affixed pile crown or half affixed pile crown.
Packing material between described concrete filled steel tube compound pile and the native hole, described steel tube concrete pile inner chamber packing material and described steel pipe congruent finished product comprise that the caking property packing material that the prefabricated concrete pipe pile of prestressed concrete pipe pile adopts is cement paste or cement mortar, or concrete, wherein can allocate the additive of various uses into, as reinforcing agent, early strength admixture, water reducing agent, expansion agent, prevent contracting agent etc.; And can allocate or not allocate into steel fibre or the charcoal fiber or the nylon matter fibrous material that can improve concrete strength and cracking resistance as required into.
Can in described steel tube concrete pile, dispose or not dispose longitudinal type steel or combination steel member inner core as required.
The job practices of steel-pipe concrete assembled pile of predrilled hole rock-embedded is characterized in that, comprises the steps:
The first step: adopt mechanical drilling method in soil layer, to hole, and the temporary steel casing is located thereon or inserts on request wherein certain degree of depth reposefully to rock surface;
Second step: adopt and bore at the petrosal foramen degree of depth of rock target drill continuation rock drilling to designing requirement, the clear end in case of necessity;
The 3rd step: concrete filled steel tube compound pile or its steel pipe shell or half pre-manufactured steel pipe concrete compound pile are put into above-mentioned boring; If segmentation is inserted in the hole, adopt between every section then that welding, bonding, bolt connect, latch connects, snap close connects or sleeve connects or by they be connected together, clear again hole before the grouting in case of necessity;
The 4th step: adopt normal pressure method for filling or high pressure pouring method at pile body or the inside and outside perfusion packing material of steel pipe shell, at the bottom of stake, begin perfusion in case of necessity, the outlet of intrusion pipe must be lower than packing material end face certain depth, the packing material end face can surpass stake top design elevation certain altitude when perfusion finished, adhere to specification with the packing material quality that guarantees pile crown, can in packing material, allocate additive in case of necessity; Can or insert vertical Steel section member before or after the perfusion packing material simultaneously.
In the 5th step, interim casing is extracted out; Can add suitable vibration in a pile body inside or a top application, so that packing material reaches closely knit effect.
The 6th step: after treating that a packing material hole in reaches certain intensity, cut away pile body and the super packing material that waters on the top design elevation, installation pile crown and cushion cap connecting elements form steel-pipe concrete assembled pile of predrilled hole rock-embedded at last.
The invention will be further described below in conjunction with the drawings and specific embodiments.
Description of drawings
Fig. 1 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded first embodiment of the present invention, is cast-in-place or prefabricated steel pipe plain concrete pile in native hole and the petrosal foramen;
Fig. 2 is along the profile of A-A line among Fig. 1;
Fig. 3 is the whole stake sectional drawing of a kind of structure of steel-pipe concrete assembled pile of predrilled hole rock-embedded second embodiment of the present invention, is cast-in-place or prefabricated steel pipe reinforced concrete pile in native hole and the petrosal foramen;
Fig. 4 is the B-B sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded second embodiment of the present invention;
Fig. 5 is the whole stake sectional drawing of a kind of structure of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 3rd embodiment of the present invention, replaces steel pipe with the prefabricated steel pipe concrete pipe pile of finished product, and steel concrete is poured at the scene in its chamber;
Fig. 6 is the profile of Fig. 5 along the C-C line;
Fig. 7 is the whole stake sectional drawing of a kind of structure of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 4th embodiment of the present invention, with steel pipe and prefabricated concrete pipe pile or the precast prestressed concrete pipe stake replacement steel pipe that is sticked together, steel concrete is poured at the scene in its chamber with cohesive material;
Fig. 8 is along the profile of D-D line among Fig. 7;
Fig. 9 is the sectional view of the steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has only showed among the figure and has added reinforcing cage in the steel pipe outside;
Figure 10 is along the profile of A-A line among Fig. 9;
Figure 11 is the sectional view of the another kind of steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has only showed among the figure and has added reinforcing cage in the steel pipe the inside;
Figure 12 is along the profile of B-B line among Figure 11;
Figure 13 is the sectional view of the another kind of steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has showed among the figure in steel pipe outside and the inside and has all added reinforcing cage;
Figure 14 is along the profile of C-C line among Figure 13;
Figure 15 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 5th embodiment of the present invention, shaped steel or combination steel member or reinforcing cage or precast reinforced concrete structure have been adopted in this steel-pipe concrete assembled pile of predrilled hole rock-embedded bottom of displaying among the figure, and irritate real with packing material;
Figure 16 is the steel-pipe concrete assembled pile of predrilled hole rock-embedded profile that adopts shaped steel or combination steel member among Figure 15 in the petrosal foramen;
Figure 17 is the steel-pipe concrete assembled pile of predrilled hole rock-embedded profile that adopts reinforcing cage among Figure 15 in the petrosal foramen;
Figure 18 is the steel-pipe concrete assembled pile of predrilled hole rock-embedded profile that adopts precast reinforced concrete structure among Figure 15 in the petrosal foramen.
The specific embodiment
Steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, mainly the formation with pile cutoff is divided into four big classes.The first kind is that pile cutoff is complete prefabricated solid concrete steel pipe pile, and pile cutoff two seals the formation pile cutoff to steel pipe 1 with steel end plate 4; Second class is to coincide in advance in the steel pipe to go up prefabricated concrete pipe pile (comprising prestressed concrete pipe pile), inject adhesive material between steel pipe and the above-mentioned prefabricated concrete pipe pile (comprising prestressed concrete pipe pile), pile cutoff two is welded together to form pile cutoff to steel pipe and above-mentioned prefabricated reinforced concrete pile tube (comprising prestressed concrete pipe pile) with steel end plate 4 solid or in the form of a ring; The 3rd class is all to adopt fished pipe concrete hollow pile tube, and the scene is concrete perfusion or cement mortar or cement paste at steel pipe concrete hollow pile tube inner chamber penetration concrete or after inserting reinforcing cage; The 4th class be only steel pipe is inserted the hole at the bottom of, injection concrete or insert steel concrete in pipe at the construction field (site) then.
Concrete in steel pipe is whole cast-in-place persons, and steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention bottom can replace to packing material between shaped steel or combination steel member or reinforcing cage or precast reinforced concrete structure and stake and the prebored hole as the pile body member that transmits load to the rock stratum.
Below in conjunction with above-mentioned accompanying drawing and five embodiment the present invention is described in detail.
At first referring to Fig. 1,2, Fig. 1 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded first embodiment of the present invention; Fig. 2 is along the profile of A-A line among Fig. 1.As can be seen from the figure first embodiment is that lengths of steel pipes 1 adds complete prefabricated or complete cast-in-place full cast-in-situ concrete 2.Connect with steel end plate 4 solid or in the form of a ring between the lengths of steel pipes 1, and complete at the scene cast-in-situ concrete section 2, cast packing material 3 in prebored hole: cement paste or cement mortar or concrete are combined in the prebored hole of soil layer A and rock B this concrete filled steel tube compound pile securely.
Referring to Fig. 3,4, Fig. 3 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded second embodiment of the present invention; Fig. 4 is along the profile of B-B line among Fig. 3.As can be seen from the figure second embodiment is that lengths of steel pipes 1 adds full precast reinforced concrete or full cast-in-situ steel reinforced concrete section 2.Connect with steel end plate 4 between the pipeline section 1,2, and pour into a mould packing material 3 at the scene in prebored hole: cement paste or cement mortar or concrete are combined in the prebored hole of soil layer A and rock B this concrete filled steel tube compound pile securely.Reinforcing cage in the steel concrete is made up of main muscle 6 and stirrup 5.
Referring to Fig. 5,6, Fig. 5 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 3rd embodiment of the present invention; Fig. 6 is along the profile of C-C line among Fig. 5.As can be seen from the figure the 3rd embodiment has replaced lengths of steel pipes 1 among the embodiment one with prefabricated steel pipe concrete pipe pile section 8, cast-in-site steel concrete or concrete 2 in the tube chamber.Prefabricated steel pipe concrete pipe pile section is made of with the concrete that its inwall links to each other lengths of steel pipes.To place in pipeline section 8 inner chambers and the corresponding built-in reinforcing bar 7 of pipeline section, connect with solid or ring-type steel end plate 4a between the two.Steel end plate 4a connects between the pipeline section 8, and pours into a mould packing material 3 at the scene in pre-manufactured hole: cement paste or cement mortar or concrete are combined in the prebored hole of soil layer A and rock B this concrete filled steel tube compound pile securely.
Referring to Fig. 7,8, Fig. 7 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 4th embodiment of the present invention; Fig. 8 is along the profile of D-D line among Fig. 7.As can be seen from the figure the 4th embodiment is except getting up to replace the steel pipe 1 with steel pipe 1 and prefabricated concrete pipe pile or precast prestressed reinforced concrete pipe pile 9 bondings with caking property packing material 10, other is the same with the 3rd embodiment, cast-in-site steel concrete or concrete 2 in the tube chamber.The caking property packing material 10 that adopts is cement paste or cement mortar or concrete, wherein can allocate the additive of various uses into, as reinforcing agent, early strength admixture, water reducing agent, expansion agent, prevent contracting agent etc.; And can allocate or not allocate into steel fibre or the charcoal fiber or the nylon matter fibrous material that can improve concrete strength as required into.
Described steel tube concrete pile can adopt the fished pipe concrete tubular pile to replace the steel pipe shell, then at fished pipe concrete tubular pile inner chamber in-site pouring concrete or steel concrete or steel reinforced concrete.
Can in described steel tube concrete pile, dispose or not dispose longitudinal type steel inner core as required.
Described multistage stake by stake end steel plate or additional welding, bonding, the bolt that connects between the steel plate connect, latch connects, snap close connects or sleeve connects or being connected together by its Men; The shaped steel of above-mentioned stake bottom or reinforcing cage or precast reinforced concrete structure by additional steel plate be connected with the welding of stake end steel plate, bonding, the bolt of the steel tube concrete pile on top, latch connects, snap close connects or sleeve connection or being connected together by them.Connected mode is known, so do not describe in detail with figure at this.
Described steel pipe shell is various seamless steel pipes or welded steel pipe, steel pipe inner face or outside or inside and outside two sides can be equipped with the steel member of longitudinal reinforcement or reinforcing cage or stirrup or opposing longitudinal shear or twine the charcoal fabric, are provided with or tube wall is not set in the steel pipe to socket the steel member; When steel pipe outside when reinforcing cage is installed only, then the steel tube concrete pile part can adopt complete prefabricated or half prefabricated half cast-in-place form of structure, also can directly adopt the fished pipe concrete tubular pile to replace the form of structure of steel pipe, the bottom of steel tube concrete pile is opened or is sealed with steel plate.
Fig. 9-14 has showed that the structural representation of steel pipe 1 described in the present invention: Fig. 9 is the sectional view of the steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has showed the reinforcing cage that has only added in the steel pipe outside by main muscle 6 representatives among the figure; Figure 10 is along the profile of A-A line among Fig. 9; Figure 11 is the sectional view of the another kind of steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has showed the reinforcing cage that has only added in the steel pipe the inside by main muscle 6 representatives among the figure; Figure 12 is along the profile of B-B line among Figure 11; Figure 13 is the sectional view of the another kind of steel pipe used of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention, has showed among the figure in steel pipe outside and the inside and has all added the reinforcing cage of being represented by main muscle 6; Figure 14 is along the profile of C-C line among Figure 13.
Referring to Figure 15,16,17 and 18, Figure 15 is the whole stake sectional drawing of steel-pipe concrete assembled pile of predrilled hole rock-embedded the 5th embodiment of the present invention; Figure 16,17 and 18 is to be with the steel-pipe concrete assembled pile of predrilled hole rock-embedded profile of shaped steel or combination steel member D among Figure 15 corresponding to the profile behind the different component that has adopted among Figure 15: Figure 16; Figure 17 is a steel-pipe concrete assembled pile of predrilled hole rock-embedded profile of using the reinforcing cage of being made up of main muscle 6 and stirrup 5 among Figure 15; Figure 18 is a steel-pipe concrete assembled pile of predrilled hole rock-embedded profile of using precast reinforced concrete structure C among Figure 15.
As can be seen from the figure shaped steel or combination steel member D are adopted or by casting with grouting agent or contain reinforcing cage master muscle 6 or/and the precast reinforced concrete structure C of stirrup cage 5 in the reinforcing cage scene that reinforcing cage master muscle 6 and stirrup cage 5 are formed in the 5th embodiment embedding rock concrete filled steel tube compound pile bottom, cast with grouting agent between precast reinforced concrete structure C and stake and the prebored hole, as the pile body member that transmits load to rock B.These members with the various embodiments described above embedding rock concrete filled steel tube compound pile look different situations can in-situ casting or link together by end plate 4a or 4b after in-situ casting again.
Job practices to steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention elaborates below, and the job practices of steel-pipe concrete assembled pile of predrilled hole rock-embedded is characterized in that, comprises the steps:
The first step: location, stake hole, auger is in place, according to pile body, petrosal foramen diameter, angle of inclination and the direction of designing requirement, holes to rock surface in soil layer, and the temporary steel casing is located thereon or inserts on request wherein certain degree of depth reposefully;
Second step: the installation of rock-boring and pile body: migrate and bore at the petrosal foramen degree of depth of rock target drill continuation rock drilling to designing requirement, the clear end;
The 3rd step: steel pipe concrete pipe pile is put into boring piecemeal.Adopt welding, bonding, bolt connection, latch connection, snap close connection or sleeve to connect or being connected together between every section by them.Set upright, locate.Clear again hole before being in the milk in case of necessity;
The 4th step: outer filling packing material in the pile tube.At the bottom of stake, begin grouting in case of necessity, the outlet of grout pipe must be lower than packing material end face certain depth, its end face must surpass stake top design elevation certain altitude when grouting finished, adhere to specification with the grouting quality that guarantees pile crown, can in grouting agent, allocate Admixture in case of necessity, coagulate to reach early, early strong, prevent effect such as cement paste contraction;
The 5th step, the extraction of interim casing, the materials such as carbon fiber that must carefully avoid injuring the coating of pile body steel pipe outside possibility spary or be wrapped in the steel pipe outside;
The 6th step: after treating the grouting agent sclerosis in the hole and reaching certain intensity, cut away pile body and the super grouting agent that waters on the top design elevation, pile crown-cushion cap connecting elements is installed, form embedding rock concrete filled steel tube compound pile at last.
Half prefabricated steel tube concrete pile is in order to alleviate the weight of solid prefabricated steel tube concrete pile, to reduce transportation, installation cost according to this.It is that the part near steel pipe is concrete prefabricated, and core is tamped by the job site fluid concrete, and half prefabricated steel tube concrete pile comprises following two kinds of preparation methods:
1. directly adopt the fished pipe concrete tubular pile to replace steel pipe, its hollow lumen is tamped by job site fluid concrete or steel concrete.
2. adopt the cohesiveness packing material that prefabricated concrete pipe pile or the superimposed steel pipe of precast prestressed concrete pipe stake are formed combined member, its hollow lumen is tamped by job site fluid concrete or steel concrete.
Described embedding rock concrete filled steel tube compound pile relies on the packing material of in-site pouring between pile body and the hole wall soil body and rock stratum transmission load towards periphery.
Range of application of the present invention, no matter the project scale size, how construction environment changes, as long as the adaptable place of prior art, the present invention nearly all can be used.
The invention has the beneficial effects as follows that pile body preparation method according to the present invention can have four kinds of multi-form whole stakes, is enough to deal with various actual needs.
All members of whole stake can both industrial mass production, even the packing material in the pile body also can accomplish commercialization (as commercial concrete, commodity cement mortar and commodity cement paste or the like), thus can carry out standardized designs, pile quality reliably, convenient construction, reduce cost.
Advantage of the present invention is:
1. utilize the steel-pipe concrete assembled pile of predrilled hole rock-embedded of the inventive method moulding, its great advantage is that the member that passes through soil layer is steel pipe or prefabricated steel pipe concrete pipe pile, can both serve as main load-bearing member in the future in dual-use material ground, the role who plays the part of interim casing again, in the whole construction course, the quality of pile body can not be interfered, and the packing material consumption obviously reduces, and interim casing pipe-pulling speed obviously improves.Because the existence of shell steel pipe, its inner concrete will three dimension stress, and the horizontal direction distortion is subjected to the constraint of steel pipe, and its compressive strength is significantly improved, thereby whole pile capacity also obtains to promote.
2. embed the pile body of rock part, can be steel tube concrete pile self or prefabricated concrete-bar component, prefabricated reinforced concrete member, also can be shaped steel or special combination steel member, they are except that can satisfying requirement of strength own, also increased as much as possible and petrosal foramen in packing material between bond area, maximum bearing capacity is provided.Adopt common method of attachment, simple structure, power transmission is direct, reliable in quality.
3. the size of concrete filled steel tube compound pile is bigger than shaped steel, and the space that can make full use of boring promotes the bending rigidity of pile body.Except that having between pile body and the hole wall the packing material protection steel pipe, but outer surface of steel tube also the various antirusting paints of spary improve the antirust ability of steel pipe.
4. concrete filled steel tube compound pile inner chamber packing material is to carry out in the steel pipe that almost seals, petrosal foramen, is subjected to the ectocine chance very little, so this packing material can be used as the part of pile body, pile strength, rigidity take this to be improved.The installation of other member be connected, be as good as with prefabricated post on the ground, do not have structural damage in the work progress, so the bearing capacity of pile body can thoroughly be brought into play.
In addition, one of them characteristic of steel-pipe concrete assembled pile of predrilled hole rock-embedded of the present invention are exactly that pile crown is handled than being easier to, because the existence of steel pipe shell, by being installed on the steel pipe top, various additional connecting elementss make hinged the connection or the fixedly connected or semifixed connection of the hinged connection of sliding between pile crown and the pile cap.Also because adopt solid or ring-type steel plate or flange connection, steel tube concrete pile is connected with the pile cutoff of different size and different structure form (as pure shaped steel stake or precast reinforced concrete pile or cast-in-situ steel reinforced concrete stake etc.) becomes very easy between the pile cutoff.