The stake mould of the directed steel fibrous concrete stake of a kind of cast-in-place X-shaped large-diameter hollow and construction method
Technical field
The invention belongs to civil construction project technical field, the stake mould of the particularly directed steel fibrous concrete stake of a kind of cast-in-place X-shaped large-diameter hollow and construction method thereof.
Background technology
Build highway, railway, bridge etc. to need to carry out consolidation process to soft foundation in soft clay area, and pile foundation and composite foundation technology thereof are the foundation treatment technologies be most widely used.Vertical Bearing Capacity of Pile Foundation is made up of pile side friction and end resistance two parts, seems particularly important in the performance of deep soft soil foundation Lateral frictional resistance.Wherein how improving unit materials rate of utilization of strength, while saving constructional materials consumption, improve bearing capacity of pile foundation, is one of important topic of paying close attention to for a long time of researcher.
Before making the present invention, Chinese patent " cast-in-place X-shaped large-diameter hollow concrete pile and construction method thereof " (patent No.: ZL201010215965.4), the technological merit of combined cast-in-situ X-shaped concrete pile and cast-in-situ concrete large-diameter tubular pile, the pile-type that consideration stake side odd-shaped cross section form and the native effect to improving unit concrete material utilization rate and bearing capacity of pile foundation of stake core is simultaneously a kind of economical rationality, cost performance is superior.But this kind of stake is plain concrete pile, its shortcoming is that horizontal shear intensity is less, and the level that is thus difficult to use in is to the very large operating mode of load, and its scope of application is restricted greatly.Therefore consider to use the steel fibrous concrete that significantly can increase pile body horizontal bearing capacity to build.
The raw material such as sand, stone, cement and steel fibre are mixed together by the preparation technology of the steel fibrous concrete of usual employing, and adding mixing water stirs, and enters mould vibration compacting.According to the steel fibrous concrete that this traditional handicraft is shaping, steel fibre is random random distribution in concrete.In Practical Project, the steel fibre of the fraction consistent or close with stake axial direction is only had just to play the effect effectively improving pile body horizontal bearing capacity.The shortcoming of existing preparation technology is that in concrete, effective utilization ratio of steel fibre is very low, and the steel fibre of considerable part cannot play the shearing resistance effect of expectation, the raw material usage preparing steel fibrous concrete also can be caused greatly to increase simultaneously.
Summary of the invention
The object of the invention is to overcome the hypodynamic defect of cast-in-place X-shaped large-diameter hollow concrete pile horizontal bearing, while considering that stake side odd-shaped cross section form and stake core soil are to raising unit concrete material utilization rate and vertical bearing capacity, significantly improve the advantage of pile body horizontal bearing capacity in conjunction with directed steel fibrous concrete, stake mould and the construction method thereof of the directed steel fibrous concrete stake of a kind of cast-in-place X-shaped large-diameter hollow of economical and efficient are provided.
The present invention is achieved through the following technical solutions:
The stake mould of the directed steel fibrous concrete stake of a kind of cast-in-place X-shaped large-diameter hollow, comprise the stake mould outer tube and the interior pipe of stake mould that arrange with one heart, a cavity structure is formed between pipe in stake mould outer tube and stake mould, stake mould outer tube is connected with the vibration head of pile driver by dismountable flange dish with the top of pipe in stake mould, in stake mould outer tube and stake mould, the bottom of pipe is connected with flap valve shoe, the top of stake mould outer tube is provided with the charging aperture communicated with cavity structure, it is characterized in that: also comprise DC power control device, pipe exterior bottom to 1/5 ~ 1/2 height pre-embossed spiral groove in described circular stake mould, to top pre-embossed two vertical lines connected in stars above spiral groove, DC coil winding screw connected in star is arranged, and the both positive and negative polarity wiring of DC coil is connected with DC power control device by the extraction of linear groove.
The stake mould of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, described stake mould outer tube is X-type stake mould outer tube, and in described stake mould, pipe is pipe in circular stake mould.
The stake mould of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, described flap valve shoe has the X-shaped identical with stake die sleeve pipe outer contour shape, comprises lock shaft and flap valve.
The stake mould of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, coats one deck self-drying type bonding insulating paint in described spiral groove.
The stake mould of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, the described DC coil number of turn is 500 ~ 600.
A construction method for the directed steel fibrous concrete stake of cast-in-place X-shaped large-diameter hollow, comprises the following steps,
(1) by stake mould and pile driving position that pile driver is being specified in place, before pile sinking, flap valve shoe is closed;
(2) Vibration on Start-up pile driver, the stake mould of the cavity structure be attached thereto is driven slowly to sink to ground, and 1.5 ~ 2.5m vibration staying, the 0.5 ~ 1.5min that often sinks, flap valve shoe is kept closed under soil pressure effect, and protection cavity structure stake mould sinks down into projected depth;
(3) in stake mould cavity structure, evenly a certain amount of steel fibrous concrete be mixed with in known ratio by cementitious material, sand, stone, high efficiency water reducing agent and steel fibre is injected by charging aperture;
(4) connect DC power control device, the DC coil be wound around in inner layer casing recess is energized, in stake mould cavity structure, produce magnetic field, and the magnetic field within the scope of cavity is basically identical with stake axis;
(5) Vibration on Start-up tube drawing, under vibrational state, steel fibrous concrete viscosity resistance is less, and steel fibre arragement direction under magnetic fields is tending towards consistent with magnetic direction, reaches directional profile state;
(6) repeat step (3) to (5), until stake mould upwards extracts ground, form the directed steel fibrous concrete stake of cast-in-place X shape large-diameter hollow.
The construction method of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, the length of steel fiber that steel fibrous concrete is selected is 8 ~ 10cm, and diameter is 1.0 ~ 1.5mm.
The construction method of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, vibration pipe-drawing pulling out speed is 0.5-1.2m/min, and every tube drawing 1m vibration staying 1.5min.
The construction method of the directed steel fibrous concrete stake of described cast-in-place X-shaped large-diameter hollow, after DC power control device is opened, the DC current in DC coil is 20-60A, and can produce magnetic induction intensity in cavity structure is 20 × 10
-3t ~ 60 × 10
-3the magnetic field of T.
Advantage of the present invention and effect are:
(1) the present invention adopts the method cast-in-place steel fibrous concrete mixture being applied to directional magnetic field, utilize magnetic induction effect to reach the object of steel fibre directional profile in concrete, overcome the shortcoming that the low and very most of steel fibre of the random random distribution of steel fibre, effectively utilization ratio that existing steel fibrous concrete moulding process causes can not play due shear resistance;
(2) because cross section outline is X shape, compared with traditional circular cross-section, there is larger girth, therefore there is higher outer frictional resistance; Owing to there is stake core soil, therefore stake inwall also has the effect of inner frictional resistance, and this pile-type utilizes cross section abnormity effect and the raising effect of stake core soil to frictional force in side-pile simultaneously, effectively improves vertical bearing capacity;
(3) the directed steel fibre X-shaped large-diameter hollow pile that the stake mould provided in the present invention and construction method are built, the steel fibre X-shaped large-diameter hollow pile that the existing method of its pile body horizontal bearing force rate is built improves 45% ~ 90%, or saving reaches steel fibre 20% ~ 50% needed for identical pile body horizontal bearing capacity;
(4) cast-in-place X-shaped large-diameter hollow concrete pile is improved, use instead directed steel fibrous concrete carry out building after its horizontal bearing capacity greatly improve, can be used as the pile foundation of highrise building, bridge, pattern foundation pit supporting structure etc., greatly expanded range of application.
accompanying drawing illustrates:
Fig. 1 is work progress schematic diagram of the present invention;
Fig. 2 is stake mould schematic diagram of the present invention;
Fig. 3 is stake mould cross sectional representation of the present invention;
Fig. 4 is power supply schematic diagram of the present invention;
In figure, 1 is vibration head, and 2 is detachable flange, and 3 is charging aperture, 4 is X-type stake mould outer tube, 5 is pipe in circular stake mould, and 6 is the both positive and negative polarity wiring of drawing from the linear pattern line of rabbet joint, and 7 for being wound in the DC coil of the spirality line of rabbet joint, 8 is flap valve shoe, 9 is DC power control device, and 10 is current adjusting knob, and 11 is power switch.
Detailed description of the invention
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further details.
As shown in Figure 2, the stake mould of the directed steel fibrous concrete stake of cast-in-place X shape large-diameter hollow, form concentric tubes cavity structure by pipe 5 in X-type stake mould outer tube 4 and circular stake mould, stake mould top is connected with vibration head 1 by detachable flange 2, connects flap valve shoe 8 bottom stake mould; The spiral groove that circular inner pipe 5 exterior bottom to 1/2 height pre-embossed 500 ~ 600 is enclosed, 1/2 height is to top pre-embossed two linear grooves; DC coil 7 is wound in spiral groove, by self-drying type bonding insulating paint form firm connection with groove, and on cover one deck self-drying type covering insulating paint as topping, its both positive and negative polarity wiring 6 is drawn by linear groove and is connected with DC power control device 9; DC power control device 9 is prior art, comprises power switch 11 and current adjusting knob 10; Power switch 11 controls whether in stake loft circle 7, to lead to direct current, and DC adjustment knob 10 is for controlling led to galvanic size of current.
As shown in Figure 1, the construction method of the directed steel fibrous concrete stake of cast-in-place X shape large-diameter hollow of the present invention, comprises the following steps:
(1) by the stake mould of pile tip with glide lamellae and pile driving position that pile driver is being specified in place, before pile sinking, flap valve shoe 8 is closed;
(2) Vibration on Start-up pile driver vibration head 1, the cavity structure stake mould be attached thereto is driven slowly to sink to ground, and every sinking 2.0m vibration staying 1min, flap valve shoe 8 is kept closed under soil pressure effect, and protection stake mould cavity structure stake mould sinks down into projected depth;
(3) in cavity structure, evenly a certain amount of steel fibrous concrete be mixed with in known ratio by cementitious material, sand, stone, high efficiency water reducing agent and steel fibre is injected by charging aperture 3, above-mentioned steel fibrous concrete, is prepared primarily of the mixing of cementitious material, sand, stone, water reducing agent and steel fibre; The length of steel fibre is 8-10cm, and diameter is 1.0-1.5cm.Its preferred preparation manipulation process is: load weighted cementitious material, sand, stone are dropped into mixer siccative and stirs, then whole load weighted steel fibre is dropped into while stirring to stirring, add load weighted mixing water and water reducing agent (as high efficiency water reducing agent) again, continue to stir 3min ~ 5min, the slump controlling steel fibrous concrete mixture within the scope of 100mm ~ 150mm, to reduce mixture viscosity resistance;
(4) open DC power supply switch 11, the DC coil 7 be wound around in pipe 5 groove in circular stake mould is energized, and the size of current controlled in DC coil by current adjusting knob 10 is 20 ~ 60, and in stake mould cavity structure, produce magnetic induction intensity is 10 × 10
-3t ~ 50 × 10
-3the magnetic field of T, its direction within the scope of cavity and stake axially basically identical;
(5) Vibration on Start-up head upwards tube drawing, above pulling out speed is 0.5-1.2m/min, and every tube drawing 1m vibration staying 1.5min.Under vibrational state, steel fibrous concrete viscosity resistance is less, and steel fibre arragement direction under magnetic fields is tending towards consistent with magnetic direction, reaches directional profile state, ensures that stake mould inner concrete surface is higher than stake mould bottom level 2m during tube drawing;
(6) repeat step (3) to (5), until stake mould upwards extracts ground, form the directed steel fibrous concrete stake of cast-in-place X shape large-diameter hollow.
Described bonding insulating paint and covering insulating paint are self-drying type insulating paint, and temperature classification is E level, and coating layer thickness is 1mm.
Flap valve shoe described in step (1) has the X-shaped identical with stake die sleeve pipe outer contour shape, is made up of lock shaft and flap valve; It is because the left and right of soil pressure is kept closed that flap valve shoe sinks to ground at stake mould, and the Gravitative Loads when stake mould extracts ground due to steel fibrous concrete will be opened automatically;
The steel fibrous concrete of the preparation described in step (3), the length of steel fiber selected is 8 ~ 10cm, and diameter is 1.0 ~ 1.5mm.Its preferred preparation manipulation process is: load weighted cementitious material, sand, stone are dropped into mixer siccative and stirs, then whole load weighted steel fibre is dropped into while stirring to stirring, add load weighted mixing water and high efficiency water reducing agent again, continue to stir 3min ~ 5min, control the steel fibrous concrete mixture slump within the scope of 100mm ~ 150mm, to reduce mixture viscosity resistance;
The known ratio preparing steel fibrous concrete described in step (3) can be learnt from " steel fiber reinforced concrete structure design and construction code " (CECS 38-1992) and " steel fibrous concrete " (JG/T3064-1999);
Dc source described in step (4) is provided by special high-power DC power supply, and maximum supply voltage is 380V.After connection dc source, the electric current in DC coil is about 20 ~ 60 peaces, and the magnetic induction intensity produced outside inner sleeve is 20 × 10
-3t ~ 60 × 10
-3the magnetic field of T, magnetic direction roughly along pile body axially.In the process of upwards tube drawing, the magnetic field of cavity structure also together on move, thus make steel fibre in whole pile body length range all reach directional profile state;
The internal diameter of the directed steel fibrous concrete stake of cast-in-place X shape large-diameter hollow of the final formation described in step (6) is 0.5 ~ 0.8m, and outsourcing circular diameter is 1.5 ~ 2.0m, and pile body maximum length can reach 30m.