CN116043834A - Bare rock pile foundation construction technology based on integrated construction floating platform - Google Patents

Abstract

The invention discloses a bare rock pile foundation technology based on an integrated construction floating platform, which relates to the field of pile foundation construction and comprises the following steps: an integrated construction floating platform, wherein pile foundation construction equipment and lifting equipment are arranged on the platform. The integrated construction platform is mainly suitable for sealing deep water environments, such as construction of bridge pile foundations in deep water lakes or reservoirs. Because the water area is not provided with a water channel communicated with an external river, the large-scale water ship and facilities cannot directly enter the bridge position for construction, and meanwhile, the requirement of large-scale hoisting is met due to deepwater. The integrated construction floating platform is adopted, the floating box bodies are respectively transported into the water, and the construction of the pile foundation is carried out after the water is assembled, wherein the construction comprises the lowering and stabilization of pile foundation pile casing, pile foundation pore-forming, the lowering of a reinforcement cage and pile foundation concrete pouring.

Description

Bare rock pile foundation construction technology based on integrated construction floating platform

Technical Field

The invention relates to the field of pile foundation construction, in particular to a bare rock pile foundation construction process based on an integrated construction floating platform.

Background

Along with the continuous development of economy and technology, highway bridge projects are more and more, the crossed terrain areas are more and more changeable, bridge pile foundations are gradually constructed from land, and the bridge is gradually transformed into construction of a river and a lake, so that the designed bridge has the characteristics of large span and long span. The pile foundation in the general river water area adopts large-scale water equipment, such as flat barge, floating crane ship and piling ship to mutually cooperate for construction. However, in some inland lakes or artificial reservoirs, large-scale water equipment cannot directly reach a construction bridge position through a water channel, natural geographic conditions such as no cover layer at the bottom, steep rock surface, ultra-deep water area and the like may exist, and when the process of the steel pipe pile trestle platform is adopted, the steel demand is large, the time for foundation treatment before erection is consumed, the high pile platform is poor in stability and risk and other adverse factors are large, so that the construction cost is increased, and the potential safety hazard is large.

Disclosure of Invention

The invention aims to solve the problems of the background technology and provides a bare rock pile foundation construction process based on an integrated construction floating platform.

In order to achieve the above purpose, the present invention provides the following technical solutions: the bare rock pile foundation construction process based on the integrated construction floating platform comprises 18 floating boxes, wherein after every 6 floating boxes are combined into three sets of double-body pressure-bearing bridge foot boats, the pressure-bearing bridge foot boats are connected and formed through bridge truss structures on a deck. And then installing impact drills according to the pile positions on the bridge truss, arranging two impact drills on the platform, and simultaneously installing a gantry crane with lifting capacity of 90t on the platform for auxiliary construction. The integrated construction floating platform is not provided with power, and all moves by virtue of a mooring system, wherein the mooring system consists of 8t winches, a cable guiding drum and land anchor rods, the winches are symmetrically distributed at the head and tail ends of a deck of a bridge foot boat, and the anchor ropes are steel wire ropes with the diameters of 22 mm.

Further, after the integrated construction floating platform is assembled, the position of the integrated construction floating platform is adjusted through a mooring system, and the integrated construction floating platform is positioned and anchored on a construction pile position;

further, punching and drilling holes on the rock surface at the pile hole by two impact drilling machines on the platform, wherein the hole diameter of the rock surface is 3m larger than the designed pile diameter, so that pile foundation pile casing and anchoring can be conveniently lowered, the hole diameter is controlled to be not smaller than the designed pile foundation diameter after 3m, namely, the designed pile foundation diameter is 2.5m, and the designed pile casing diameter is 2.7m;

further, the pile foundations at the pile positions are subjected to hole forming operation firstly, and then pile foundation casing is lowered;

further, the pile casing is transported to an integrated construction floating platform in segments through a buoyancy tank material transportation platform, and is lifted, lengthened and lowered through a gantry crane;

further, anchoring the pile casing by adopting an underwater pile foundation pile casing anchoring method, and anchoring the pile casings of the pile positions with holes;

further, after the pile casings are anchored, the pile foundation pile casings are connected into a whole by adopting a horizontal parallel joint, and the horizontal parallel joint adopts an I25a I-shaped steel structure;

further, cleaning holes in the anchored pile foundation pile casing, then transporting the reinforcement cage to an integrated construction floating platform in sections through a floating box material transporting platform, lifting, lengthening and lowering through a portal crane, and performing secondary hole cleaning after finishing;

further, a pump pipe, a pouring guide pipe, a guide pipe hopper and a collecting hopper are installed, concrete is pumped into the collecting hopper by two land pumps on the shore, and then the concrete is poured into the holes through the collecting hopper.

Further, after the pile foundation at the pier position is constructed according to the opposite support construction sequence, the horizontal parallel connection is removed, the platform is stably moved out of the construction pile position through the mooring system, and the next designed pier position is positioned.

The invention has the beneficial effects that:

the construction process of bare rock pile foundation based on the integrated construction floating platform effectively solves the problem that large-scale water construction equipment cannot be directly entered in inland lakes or artificial reservoirs, and meanwhile, large-length pile foundation construction is performed due to steep bare rock. The single buoyancy tank can be transported into water through the flat car, the combined buoyancy tank platform is strong in structure, the gate crane can be used for maximally meeting lengthening and lowering of the large-length pile foundation pile casing, meanwhile, the process can be changed to save time and cost for foundation treatment in the earlier stage, the risk of building a deep water high-pile platform is avoided, the material consumption of the trestle platform is saved, the integrated construction floating platform can be recycled, the construction efficiency can be improved by adopting the underwater pile foundation pile casing anchoring method, and the construction period cost is saved.

Drawings

The invention is further described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of the construction floating platform of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Referring to FIG. 1, the invention relates to a floating platform for integral construction of a water pile foundation, which consists of 3 sets of combined double-body bearing bridge foot boats, 1 set of upper bridge truss structure, a gantry crane, a mooring system and pile foundation construction equipment;

and 3 sets of double-body bridge foot boats are provided with deck supports, an upper bridge truss is connected with the deck supports and connects three sets of double-body bridge foot boats to form a construction floating platform, a punching machine drilling machine is placed on the upper bridge truss structure, two sets of bridge foot boats on the outer side are provided with gantry crane tracks, then gantry cranes are installed, and an integrated construction floating platform is formed after the installation is completed.

The mooring system comprises a pontoon system (comprising anchors, anchor chains and pontoons) or a shore-ground anchor, a mooring winch (comprising a mooring rope), a cable guider, a cable stopper and the like, which are symmetrically distributed at the head end and the tail end of a deck of a foot boat of a side bridge of the platform, and the set of system can fix and move the platform in a small range;

wherein, 3 sets of binary pressure-bearing bridge foot boats are the interval setting side by side, and every set of binary pressure-bearing bridge foot boat is formed by 6 monomer boat structures combination, every two transverse connection, then head and tail are connected.

The single monomer boat size is 6m (length) ×2.5m (width) ×2m (depth), and the combined single set of double-body bridge boat size is 36m (length) ×5m (width) ×2m (depth).

And the middle bearing bridge foot boat deviates to one end by 6 meters, so that the other end forms 1 14m multiplied by 6m harbor pool for the material transportation platform to lean against and hoist the material by the portal crane. The integrated construction floating platform provides buoyancy and stability assurance; meanwhile, acting force generated during the operation of the impact drilling machine, acting force generated during the hoisting of the gantry crane and upper load of the acting force are uniformly transmitted to the buoyancy tank through the upper bridge truss structure.

The upper bridge truss structure of the integrated construction floating platform is provided with two I-steel frames, and each I-steel frame structure is formed by assembling and welding 8 40# I-steel (Q345A) and a plurality of transverse short I-steel reinforcing beams.

The deck is provided with a bridge girder connecting support, and the support structure is formed by modifying 36a I-steel and is used for supporting an upper bridge girder structure and is arranged at the deck boat side of the bridge foot boat.

The end anti-torsion stiffening beam assembly is formed by splicing and welding 2 No. 40 channel steel, is arranged on the deck of the end part of the bridge foot boat and is used for increasing the anti-torsion rigidity of the platform.

The two groups of buoyancy tanks at the outer side are provided with gantry crane track assemblies, and each track assembly consists of a P50 steel rail, a track supporting beam and a deck distributing beam.

The P50 track is arranged at the upper middle position of the track supporting beam and is firmly fixed by a pressing plate. The track supporting beam is formed by parallel assembly welding of 2 36a I-steel groups, and is arranged on a deck distribution beam, wherein the deck distribution beam consists of 52 36a I-steels with the length of about 1.2 meters, and the 52I-steels are respectively welded in the middle of the deck of the combined bridge foot boat at two sides of the platform, and the interval is 1280mm.

The travelling mechanism of the gantry crane is provided with an anti-skid gear, and the rail supporting beam is provided with a rack, so that the travelling mechanism of the gantry crane can be prevented from skidding on the rail when the floating platform is inclined under load. The crane is used on a water buoyancy tank, and the maximum inclination angle of the working state is smaller than 1.5 degrees; the maximum inclination angle in the non-working state is less than 3 degrees.

The 2 punching drills are respectively arranged on the two sets of upper bridge truss I-steel, and the hoisting movements of the drills, the hole cleaning guide pipe, the pouring guide pipe and the impact hammer are completed through hoisting of the gantry crane. The platform does not have self-propulsion capability, and the winch is installed around the pile foundation construction platform to move the platform through the shore pulling anchor.

The assembling process of the integrated construction floating platform comprises the following steps:

step 1: buoyancy tank assembly

The single buoyancy tank with the size of 12 multiplied by 2.5 multiplied by 2m (length multiplied by width multiplied by height) is transported to the site through a flat car, the single buoyancy tank is hoisted and launched by an 85t crawler crane on a code head, preliminary mooring is carried out by a mooring rope after the launching, and then the assembly of a single set of double-body pressure-bearing bridge foot boat is carried out on water;

after a single bridge foot boat is hoisted into water by a crawler crane, the assembly process sequence of the floating pile foundation construction platform is as follows:

the 6 square buoyancy tanks are transversely connected in pairs and then connected end to end. The connecting joints are designed, so that personnel can operate on the deck of the buoyancy tank;

after each set of double-body pressure-bearing bridge foot boat is assembled, a bridge truss support at the upper part of a deck is installed, and a deck distribution beam and a track support beam are installed on an outer buoyancy tank.

The upper bridge truss structure is installed. The upper bridge girders are divided into two sets of 2 pieces according to the design, each upper bridge girder consists of 4 40# I-steel, and each 4 girders are reinforced by transverse short I-steel. After being processed and spliced into a whole in a post-field, each set of bridge girder is directly installed on a deck bridge girder support, bolt holes are formed in a 40# I-steel wing plate, and the bridge girders are fixedly connected with the deck bridge girder support through high-strength bolts.

After the upper bridge girder is installed, the P50 track and the portal crane are installed.

Gantry crane installation

The portal crane has the structural characteristics and functions of being suitable for general portal cranes, is specially processed in structure, mechanism and electric control system, and is suitable for operation on a water buoyancy tank. The special functions are mainly as follows;

the anchor ingot state is locked by the rail clamping device, the anchor ingot is fixed by the pin shaft, the cable rope is fastened, and the iron shoe is wedged.

The crane is truss type and consists of door frame, trolley assembly, cart running mechanism, electric control equipment, etc. The portal frame is in a truss type and consists of truss double main beams, truss rigid legs, truss sub-rigid legs, a walking board fence and the like, wherein the main beams are connected with the portal legs through high-strength bolts. In order to adapt to the functions of wave and inclination on water, the two door legs are in a double-rigid-leg type rather than a rigid-flexible door leg type, so that the structural stability and safety of the portal frame under the wave and inclination working conditions are improved.

The cart running mechanism is in a four-trolley type, is driven by four corners respectively, and is all the driving trolleys. The number of wheels of the crane cart is 4x2=8, the wheels are assembled with an angular bearing box with rolling bearings and then are arranged on the trolley frame, wheel sets with gears are respectively arranged on two sides of the gantry crane and meshed with racks, and horizontal wheels are arranged on each trolley, so that the crane cart has the functions of climbing and preventing sliding under wave and inclined working conditions.

The trolley of the crane consists of a trolley frame, a lifting mechanism and a trolley running mechanism, wherein the trolley running mechanism is provided with four-corner driving trolleys, 2 electric hoist traction devices are respectively arranged at two ends of a main beam of the lifting machine, each trolley is provided with a horizontal wheel, and the trolley running mechanism has the functions of climbing and preventing sliding under wave and inclined working conditions; the lifting mechanism is provided with double limit protection (two sets of lifting safety limit switch devices are arranged); the trolley is powered by a suspension type cable conductive (a track used by a cable pulley is a sliding cable steel wire rope) and a pair of hooks are independent I-shaped steel tracks, and the independent I-shaped steel tracks are fixed below the main beam;

running gear installs

The running gear wheel is positioned to the appointed installation position on the track, and is padded stably and leveled by sleeper or section steel. The span difference is smaller than or equal to 5mm by welding connection, the diagonal difference is smaller than or equal to 5mm, the horizontal deflection of the wheels is smaller than or equal to 0.8/1000, the perpendicularity difference is smaller than or equal to L/400, and the span deviation is smaller than or equal to 5mm, so that the wheels reach the standard;

leg assembly and upper beam fixation

Assembling the supporting legs on the buoyancy tank, paying attention to the number and the mark of each rod piece, temporarily fixing the upper cross beam so as to avoid the swing of the upper cross beam, and measuring the parallelism of the top surface of the upper cross beam and the lower hinged support surface to be not more than 2mm;

standing and hoisting support leg and fixing cable rope

The angle of the cable rope at the outer side of the buoyancy tank is larger due to the limitation of the field, a rigid support is additionally arranged at the inner side of each supporting leg for safety, the support adopts 10# channel steel with the section, and each supporting leg adopts two supporting legs. The cable rope is a phi 14 steel wire rope, the breaking force coefficient of the steel wire rope is 1770, the included angle between the cable rope and the ground is 78 degrees, the tension of the cable rope is adjusted through a chain block, the tension of the cable rope is about 800Kg when the cable rope is tensioned, one end of the cable rope is fixed on a door leg, the other end of the cable rope is clamped and fixed on a 5t chain block through the steel wire rope, and the chain block is hung on a ground anchor;

main girder hoisting device

The girders are assembled at the rear place, and are transported to the lower part of the main arm of the crawler crane by a flat car, and a single girder is integrally hoisted; the gravity center of the girder is in the midspan, the girder is lifted by adopting a method of hanging the girder in a pocket way, and when the girder is lifted, an installer hooks at a hanging point and the crane is in unified command. In order to prevent the steel wire rope from being damaged or slipping during hoisting, rubber or hard wood plates are padded at the hoisting points;

after the hooking is finished, under the command of a crane, the crawler crane slowly rises, and after the steel wire rope is stressed, the crane stops, and whether the lifting point is abnormal or not is checked. When no abnormality is confirmed, the crawler crane slowly lifts, and the main beam is lifted to be slightly higher than the landing leg connecting surface;

after the test crane is used for testing, the main beam is slowly lifted, and is uniformly commanded by a signaling worker during lifting, and when the main beam leaves the ground for 2 meters, the main beam stops when the equal height exceeds the landing leg flange. Until the connecting centers of the main beam and the supporting leg are opposite and stable, and are connected through bolts. And loosening the lifting hook after the bolts are connected and fixed, removing the steel wire rope, and completing the hoisting work of the main beams of the equipment, wherein the two main beams adopt the same hoisting mode.

Wherein, the falling beam is arranged on the two supporting legs at the same time, and the falling beam is not suitable to be arranged in sequence; when the main beam is positioned, after the main beam falls down on the supporting legs respectively, the main beam and the supporting legs can be fastened and connected by bolts after the span positioning size measured by a measuring person meets the deviation requirement;

hoisting crane hoist

Before the crane is hoisted, the track size of the trolley is checked and rechecked after the main beam connecting beam is installed. Separately hoisting the frame and the winch, and hoisting other accessories on the trolley according to the last hoisting;

ladder and railing installation and electric cabinet positioning installation

Mounting a ladder and a railing, and firmly supporting and screwing screws after the mounting is completed;

wire rope, installation of installation cable drum and installation of accessories

The cable drum is mounted on the lower cross beam. And (5) threading and winding the main hook steel wire rope and the auxiliary hook steel wire rope. Mounting a platform, an escalator and a safety system;

note that: before the steel wire rope is wound, the defects of broken wire, abrasion, deformation and the like need to be checked, and the steel wire rope can be installed after the use requirement is met. When the winding machine winds and unwinds the steel wire rope, the winding drum steel wire rope is reserved for not less than 3 circles.

When in installation, the steel wire rope should be prevented from being stained with sediment; the rope end is pricked by thin steel wires. The two ends of the steel wire rope are fixed at the two ends of the winding drum through pressing plates and bolts respectively, and after the installation, the steel wire rope is coated with lubricating grease.

The bare rock pile foundation construction process based on the integrated construction floating platform comprises the following steps:

after the floating platform is assembled and checked, the floating platform is positioned to a construction pile position, and a punching hole is punched on a designed pile position by adopting a percussion drill, so that the elevation value of the bottom of the designed hole is directly punched from the rock face.

And then transporting the segmented pile casing segments to a harbor pool of the integrated construction floating platform through the material transportation platform, lifting, turning over, positioning and lengthening the pile casing segments through the gantry crane, and then lowering the pile casing segments, wherein the gradient of the platform is determined through a level bar in the lengthening process so as to ensure the perpendicularity of pile casing construction.

After the pile casing is lengthened in place, the anchoring of the pile casing is completed by adopting an underwater pile casing anchoring mode, and then secondary hole cleaning is carried out. An underwater pile foundation casing anchoring process comprises the following steps:

(1) The pile casing is lengthened and put into the rock for 3m, and the welding bracket is hung on a positioning frame of the integrated construction floating platform;

(2) Installing a hole cleaning guide pipe, and reversely circularly cleaning sediment in the hole by using gas lift, wherein the hole cleaning depth is 1m deeper than the pile casing feet, and the pile foundation pile casing can be repeatedly lifted and lowered in the hole cleaning process, so that the sediment on the hole wall is cleaned;

(3) Installing a pouring guide pipe in the pile casing, pouring concrete from the inside of the pile casing, repeatedly lifting and lowering the pile casing through a portal crane to enable the concrete in the pile casing to flow out of the hole, simultaneously measuring elevation of the concrete surface inside and outside the pile casing, determining height difference, ensuring anchoring effect of the concrete, controlling lifting height of the pile casing to be not more than 1m in the process, and avoiding lifting the pile casing out of the hole;

(4) Before the initial setting of the concrete, the gantry crane lowers the pile casing to the designed elevation, and then increases the pile casing by 3cm, so that the pile casing is vertically stressed under the dead weight state, and the verticality of the pile casing is ensured;

(5) And (3) the concrete is equal in strength, anchoring is completed between the pile casing and the rock wall through the concrete, a drilling machine is installed for secondary hole cleaning, and the concrete in the pile casing is punched.

The secondary hole cleaning is mainly to clean concrete in the pile casing, crush the concrete by punching and chiseling, and clean concrete slag by matching with gas lift reverse circulation. Note that when the upper and lower parts of the root of the pile casing are respectively 1m, the stroke of the impact hammer is strictly controlled to be not more than 50cm, so that the impact hammer tooth is prevented from being hung on the pile casing foot to cause the occurrence of blocking hammer or other accidents.

After the hole cleaning is completed, the reinforcement cage is transported in sections through a material transportation platform, and is lowered and fixed by adopting the same process.

And finally, pouring pile foundation concrete, and pumping the concrete into a collecting hopper on the integrated floating construction platform by adopting two ground pumps and a pump pipe. Before pouring underwater concrete, the guide pipe, the collecting hopper and the funnel are put in place, the funnel and the pouring guide pipe are arranged in the pile casing, and the guide pipe is connected by screw threads. And a rubber water stop washer with the thickness of 4-5mm is arranged between the two flange plates.

Before the catheter is used, whether the catheter is damaged or not is firstly checked, whether the sealing ring and the bayonet are perfect or not, whether the inner wall is smooth and round or not, whether the joint is tight or not, and tensile resistance and anti-leakage tests are carried out, and the catheter can be used after the test is qualified.

The distance from the bottom of the guide tube to the bottom of the hole is 350mm when the guide tube is placed.

When the underwater concrete is poured, before the first batch of concrete is poured, a water-proof bolt piece is arranged in the funnel, and a discharge hole valve of the storage hopper is closed. The storage hopper and the funnel are filled with concrete, and after other works are completely prepared, the balls can be sheared for pouring.

The concrete pouring flow of the floating box pile foundation is as follows:

(1) starting a ground pump to convey concrete, and filling the storage hopper and the hopper with concrete;

(2) firstly, a discharge hole valve of the storage hopper is opened, so that after the concrete in the storage hopper smoothly and continuously flows out, a water-proof bolt sheet of the hopper is quickly pulled out, pile foundation concrete is continuously poured, and the first-disc concrete pipe burying depth is met.

(3) When the guide pipe is removed, the discharge hole of the storage hopper is closed, concrete can be continuously pumped into the storage hopper at the moment, the number of sections of the guide pipe is controlled according to the depth of the buried pipe, the depth of the buried pipe is controlled to be 2-6m, and after the guide pipe is removed, the discharge hole of the storage hopper is opened again for pouring.

And the buoyancy tank is forbidden to move or bear other loads within 24 hours after the concrete pouring of each pile foundation is finished, so that the influence on the quality in the initial setting process of the concrete is avoided.

And symmetrically constructing other pile foundations at the pier position, and horizontally moving the integrated construction floating platform out of the pile position through a mooring system after the construction is completed, and constructing the next pier position.

The foregoing describes one embodiment of the present invention in detail, but the description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.

Claims (7)

1. The bare rock pile foundation technology based on the integrated construction floating platform is characterized by comprising the following steps of:

step 1: the 6 square buoyancy tanks are transversely connected in pairs and then connected end to end;

step 2: a deck bridge truss support of a single-set double-body pressure-bearing bridge foot boat is installed; then installing a gantry crane track on the deck; assembling each set of double-body pressure-bearing bridge foot boat on water in sequence, and then simply mooring and positioning;

step 3: upper bridge truss structure installation: each set of bridge girders is directly installed on a deck bridge girder support after being processed and spliced into a whole in a back field;

step 4: finally, installing a pedestrian gangway and auxiliary facilities; the buoyancy tank platform is designed to adopt an MG90/10t-19m-10m gantry crane to carry out hoisting operation.

2. The bare rock pile foundation process based on the integrated construction floating platform according to claim 1, wherein in step 1, the process comprises assembling a floating box;

after the single bearing boat is manufactured in a processing field and checked and accepted, the bearing boat is pre-assembled in the field, the assembling sequence is recorded, marks are made on each box body, and the bearing boat is assembled in the field according to the pre-assembling sequence after being transported to the field.

3. The bare rock pile foundation process based on the integrated construction floating platform, according to claim 1, is characterized in that after single bearing bridge foot boats are transported to a field trestle, the single bearing bridge foot boats are sequentially lifted on the trestle through an 85t trestle crawler crane to be launched, preliminary mooring is carried out through mooring ropes after the launching, and then the assembly of single-set double bearing bridge foot boats is carried out on water.

4. The bare rock pile foundation process based on the integrated construction floating platform according to claim 1, wherein the dead weight of a single pressure-bearing bridge-foot boat is 12.6t.

5. The bare rock pile foundation process based on the integrated construction floating platform according to claim 1, wherein the lifting capacity of the 85t crawler crane with the lifting radius of 10m is 25.2t.

6. The bare rock pile foundation process based on the integrated construction floating platform according to claim 1, wherein the gantry crane is specially treated: the crane is used on a water buoyancy tank, and the maximum inclination angle of the working state is smaller than 1.5 degrees; the maximum inclination angle in the non-working state is less than 3 degrees and is in an anchor ingot state;

the anchor ingot state is locked by the rail clamping device, the anchor ingot is fixed by the pin shaft, the cable rope is fastened, and the iron shoe is wedged.

7. A bare rock pile foundation process based on an integrated construction floating platform according to claim 1, wherein the crane structural pattern is a truss pattern.

Images