Construction method of static pressure pipe pile with air lift and bottom cleaning
Technical Field
The invention relates to the technical field of pile foundation construction, in particular to a construction method of a gas lift bottom cleaning static pressure pipe pile.
Background
The static pile pressing method is characterized in that the self weight of a static pile pressing machine and the total weight of a pile frame counterweight are used as reaction forces, a prefabricated pile is pressed into the soil, continuous operation is kept in construction, the pile length can be continuously welded and lengthened, and the requirements of the designed pile length and the bearing capacity are met. In some regions, due to the complex geological composition, obvious layering of miscellaneous fill, medium fine sand, silty clay, fine sand and medium sand and high standard penetration number, the construction efficiency of the regions is low, and even if the bearing capacity of the pile exceeds the design requirement, the requirement of the building design of more than eighteen layers on the ground of the underground layer can not be met.
Chinese patent application CN108625372A discloses a high-pressure flushing gas-lift reverse circulation guide hole pile sinking construction method for a compacted sand layer of a static pressure prestressed pipe pile, which comprises the following steps: (1) putting a pile driver in place, and sinking the prestressed pipe pile at a position where pile driving is needed; (2) putting the high-pressure gas-liquid jet pipe into the pile bottom of the pile pipe of the prestressed pipe pile, opening the high-pressure gas-liquid mixing device to jet high-pressure gas and liquid, and simultaneously putting the high-pressure gas-liquid jet pipe down until the high-pressure gas-liquid jet pipe penetrates through a compact sand layer; (3) and continuing sinking the pile until the design depth. High-pressure gas and liquid are output through the high-pressure gas and liquid jet pipe, impact cutting is carried out on a compact sand layer at the pile bottom position of the pile pipe, negative pressure is generated in the pile pipe to form gas lift reverse circulation, the high-pressure gas and liquid jet pipe ejects the pile pipe from the gap between the high-pressure gas and liquid jet pipe and the pile pipe, sand is carried to return to the ground, and pile sinking benefits of the prestressed pipe pile are greatly improved.
This patent technique mainly relies on the impact of rivers air current mixture to realize the clear hole limit in limit and presses the stake, and rivers and air current consumption are great, and if in the regional construction that is close to the sea level, groundwater is the sea water, and corrosivity is big, and the damage that rivers impact led to the fact the ground is big, influences the stability of pile sinking, and vibration and noise in the work progress also can influence resident on every side.
Disclosure of Invention
The invention aims to provide a construction method of a gas lift bottom cleaning static pressure pipe pile, which overcomes the defects of the prior art, can realize rapid construction in deep and dense sand layer geology at sea edge, avoids vibration and noise in the construction process, saves air source, does not damage a foundation and ensures pile sinking stability.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a construction method of a gas lift bottom cleaning static pressure pipe pile comprises the following steps:
(1) measuring and positioning, determining the positions of a static pile press and a tubular pile, positioning the static pile press, hoisting a first section of tubular pile by using a crane, hoisting the first section of tubular pile into the static pile press, and aligning the first section of tubular pile;
(2) when the first section of tubular pile is pressed to be close to the bearing capacity by using a static pile pressing machine, stopping pressing the first section of tubular pile, wherein the first section of tubular pile is mainly pressed into a miscellaneous fill layer in the pile pressing process; the method is characterized in that a vibration hole cleaner is communicated with an air compressor through a hose, the vibration hole cleaner is inserted into a first section of tubular pile through a crane, sand in the first section of tubular pile is blown out of the first section of tubular pile through the cooperation of the air compressor and the vibration hole cleaner, only hole cleaning and pile pressing are carried out in the process, the hole cleaning efficiency is high, when the sand is cleaned to be close to the bottom of the tubular pile, a static pile press is started again, the pile is pressed downwards synchronously while hole blowing is carried out, and pressing is stopped until the first section of tubular pile is pressed to be connected with a second section of tubular pile, so that the pressing efficiency can be improved, and the first section of tubular pile can be protected from being damaged;
(3) continuing to blow air downwards to blow holes until the air is blown to a position 0.8-1.5 m above the pile bottom, stopping blowing air, lifting the vibration hole cleaner out of the first section of tubular pile through a crane, and blowing holes before installing a second section of tubular pile, so that hole blowing operation is more convenient, the pressing-in efficiency of the subsequent second section of tubular pile can be effectively improved, and the second section of tubular pile is protected from being damaged in the pressing-in process;
(4) connecting a second section of tubular pile to a first section of tubular pile, performing cooling and anticorrosion treatment, inserting a vibration hole cleaner into the second section of tubular pile and the first section of tubular pile through a crane, punching while performing pile pressing operation through the matching of an air compressor and the vibration hole cleaner until the second section of tubular pile is pressed to be connected with a third section of tubular pile, stopping pressing, vibrating while the vibration hole cleaner punches sandy soil upwards along the inner walls of the second section of tubular pile and the first section of tubular pile through air flow impact, improving the pile pressing efficiency, avoiding the bearing capacity of the tubular pile exceeding the design requirement and forming a good protection effect on the tubular pile;
(5) continuing to blow air downwards to blow holes until the air is blown to be 0.8-1.5 m above the pile bottom, stopping blowing air, lifting out the vibration hole cleaner by a crane, and continuing to blow the holes downwards before the third section of tubular pile is installed, so that the hole blowing operation is more convenient, the pressing-in efficiency of the subsequent third section of tubular pile can be effectively improved, and the third section of tubular pile is protected from being damaged in the pressing-in process;
(6) connecting a third section of tubular pile to a second section of tubular pile, performing cooling and anticorrosion treatment, inserting a vibration hole cleaner into the third section of tubular pile, the second section of tubular pile and the first section of tubular pile through a crane, punching while performing pile pressing operation through the matching of an air compressor and the vibration hole cleaner, hoisting the third section of tubular pile out of the vibration hole cleaner through the crane after the third section of tubular pile is pressed, and conveying the third section of tubular pile to a designed depth through a pile conveyor; the vibration hole cleaner can upwards wash out sand along the inner walls of the third section of tubular pile, the second section of tubular pile and the first section of tubular pile by air flow impact while vibrating, so that the pile pressing efficiency is improved, the bearing capacity of the tubular pile is prevented from exceeding the design requirement, and a good protection effect is formed on the tubular pile.
Furthermore, the vibrating hole cleaner comprises a plurality of blast pipes and a vibrator arranged on the uppermost blast pipe, the blast pipes are sequentially connected from top to bottom, the lower end of the lowermost blast pipe is provided with a conical closing-in, and the tail end of the closing-in is a side opening; air compressor passes through the hose with high-pressure draught and transmits to the blast pipe, the blast pipe is at first section tubular pile under the effect of vibrator, second section tubular pile, the interior side vibration limit blowout high-pressure draught of third section tubular pile, strike the inside sand and soil of tubular pile, upwards rush out sand and soil along the inner wall of second section tubular pile and first section tubular pile, and supplementary static air compressor machine carries out the piling operation, the efficiency of piling has not only been improved, and effectively avoid the tubular pile bearing capacity to exceed the design requirement, form good guard action to the tubular pile.
Furthermore, the diameter of the closed tail end of the air supply pipe positioned at the lowest end is 0.6-0.7 times of the diameter of the air supply pipe; the air supply pipe at the lowest end can be inserted into silt and clay in a pile hole, the pipe is not easy to block, the insertion force is large, and the footage speed is high by matching with a vibrator.
Further, the length of the vibration hole cleaner in the step (2) is matched with the length of the first section of tubular pile; the vibration hole cleaner in the step (4) is additionally connected with an air supply pipe on the basis of the vibration hole cleaner in the step (2) and is matched with the total length of the first section of tubular pile and the second section of tubular pile; and (4) adding an air supply pipe on the vibration hole cleaner in the step (6) on the basis of the vibration hole cleaner in the step (4), and matching the total length of the first section of tubular pile, the second section of tubular pile and the third section of tubular pile.
Further, the inner diameter of the main body of the blast pipe is 0.08-0.3 times of the inner diameter of the first section of tubular pile, the second section of tubular pile or the third section of tubular pile; the blast pipe is matched with the vibrator to be used in the range, and the hole cleaning effect formed by air flow impact is better.
Furthermore, the pipe wall of each blast pipe is provided with a circle of upward-inclined vent holes, part of gas is flushed out from the vent holes towards the inclined upper part, and sandy soil flushed up by the blast pipe at the lowest end is assisted to be discharged outwards.
Furthermore, the diameter of the vent hole is 0.02-0.08 times of the inner diameter of the main body of the blast pipe, the pressure of the impact airflow formed by the vent hole is large in the range, and the impact force of the blast pipe at the lowest end on the sand in the pile hole is not influenced.
The invention has the beneficial effects that: compared with the prior art, the construction method of the gas lift bottom cleaning static pressure pipe pile has the following advantages: can be under various geological rings construction, especially also can realize constructing rapidly in the deep and closely knit sand layer geology of seashore, avoid vibration and noise in the work progress, practice thrift the air supply, guarantee pile sinking stability, air compressor passes through the hose with high-pressure draught and transmits to the blast pipe, the blast pipe is at first section tubular pile under the effect of vibrator, second section tubular pile, the interior side vibration limit blowout high-pressure draught of third section tubular pile, strike the inside sand and soil of tubular pile, upwards rush out sand and soil along the inner wall of second section tubular pile and first section tubular pile, and supplementary static compressor machine carries out the pile pressing operation, the efficiency of pile pressing has not only been improved, and effectively avoid the tubular pile bearing capacity to exceed the designing requirement, form good guard action to the tubular pile.
Drawings
FIG. 1 is a schematic structural view of a vibratory hole cleaner of the present invention;
wherein, 1 blast pipe, 2 vibrators, 3 closing-in ports, 4 side openings and 5 hoses.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
Example 1
Item address: is positioned near West Lu 360 of Wenhai city, circui district culture;
the surrounding environment of the project: a Weigao ocean hall is arranged on the west side of the project, a residential building is arranged on the south side, and the sea is close to the north side within 100 m;
project geological conditions: according to geological reports, soil layers comprise miscellaneous fill, medium fine sand, silty clay and medium fine sand, wherein the silty clay and the fine sand have high medium sand content and high standard penetration number;
the project requirement is as follows: the building design is 1 layer underground and 18 layers above the ground;
the project requirement is as follows: the influence of vibration and noise disturbing residents is avoided;
project scheme planning: the original scheme considers long spiral piles, long spiral guide holes, CFG (cement fly-ash gravel), extruded and expanded piles, hammered piles, water flushing methods (underground water is seawater and has high corrosivity), ramming and expanding methods, bored piles, rotary excavating and cast-in-place pile methods and the like, and all the methods cannot meet the design requirements through field surveying.
The construction method for the static pressure pipe pile by adopting the gas lift bottom cleaning finally comprises the following steps:
(1) measuring and positioning, determining the positions of a static pile press and a tubular pile, positioning the static pile press, hoisting a first section of tubular pile by using a crane, hoisting the first section of tubular pile into the static pile press, and aligning the first section of tubular pile;
(2) when the first section of tubular pile is pressed to be close to the bearing capacity by using a static pile pressing machine, stopping pressing the first section of tubular pile, wherein the first section of tubular pile is mainly pressed into a miscellaneous fill layer in the pile pressing process; the method is characterized in that a vibration hole cleaner is communicated with an air compressor through a hose, the vibration hole cleaner is inserted into a first section of tubular pile through a crane, sand in the first section of tubular pile is blown out of the first section of tubular pile through the cooperation of the air compressor and the vibration hole cleaner, only hole cleaning and pile pressing are carried out in the process, the hole cleaning efficiency is high, when the sand is cleaned to be close to the bottom of the tubular pile, a static pile press is started again, the pile is pressed downwards synchronously while hole blowing is carried out, and pressing is stopped until the first section of tubular pile is pressed to be connected with a second section of tubular pile, so that the pressing efficiency can be improved, and the first section of tubular pile can be protected from being damaged;
(3) continuing to supply air and blow holes downwards until the air is blown to about 1 m above the pile bottom, stopping supplying air, lifting the vibration hole cleaner out of the first section of tubular pile through a crane, blowing holes before installing a second section of tubular pile, and thus, the hole blowing operation is more convenient, the pressing-in efficiency of the subsequent second section of tubular pile can be effectively improved, and the second section of tubular pile is protected from being damaged in the pressing-in process;
(4) connecting a second section of tubular pile to a first section of tubular pile, performing cooling and anticorrosion treatment, inserting a vibration hole cleaner into the second section of tubular pile and the first section of tubular pile through a crane, punching while performing pile pressing operation through the matching of an air compressor and the vibration hole cleaner until the second section of tubular pile is pressed to be connected with a third section of tubular pile, stopping pressing, vibrating while the vibration hole cleaner punches sandy soil upwards along the inner walls of the second section of tubular pile and the first section of tubular pile through air flow impact, improving the pile pressing efficiency, avoiding the bearing capacity of the tubular pile exceeding the design requirement and forming a good protection effect on the tubular pile;
(5) the hole blowing is continuously carried out by downward air supply until the air blowing exceeds about 1 m of the bottom of the pile, the air supply is stopped, the vibration hole cleaner is lifted out by a crane, the hole blowing is continuously carried out before the third section of tubular pile is installed, the hole blowing operation is more convenient, the press-in efficiency of the subsequent third section of tubular pile can be effectively improved, and the third section of tubular pile is protected from being damaged in the press-in process;
(6) connecting a third section of tubular pile to a second section of tubular pile, performing cooling and anticorrosion treatment, inserting a vibration hole cleaner into the third section of tubular pile, the second section of tubular pile and the first section of tubular pile through a crane, punching while performing pile pressing operation through the matching of an air compressor and the vibration hole cleaner, hoisting the third section of tubular pile out of the vibration hole cleaner through the crane after the third section of tubular pile is pressed, and conveying the third section of tubular pile to a designed depth through a pile conveyor; the vibration hole cleaner can upwards wash out sand along the inner walls of the third section of tubular pile, the second section of tubular pile and the first section of tubular pile by air flow impact while vibrating, so that the pile pressing efficiency is improved, the bearing capacity of the tubular pile is prevented from exceeding the design requirement, and a good protection effect is formed on the tubular pile.
In this embodiment, as shown in fig. 1, the vibrating hole cleaner includes a plurality of blast pipes 1 and a vibrator 2 disposed on the blast pipe 1 located at the uppermost end, the blast pipes 1 are sequentially connected from top to bottom, a tapered closing-in 3 is disposed at the lower end of the blast pipe 1 located at the lowermost end, and the tail end of the closing-in is a side opening 4; air compressor passes through hose 5 with high-pressure draught and transmits to blast pipe 1, blast pipe 1 is at first section tubular pile under the effect of vibrator 2, second section tubular pile, the interior side vibration limit blowout high-pressure draught of third section tubular pile, strike the inside sand and soil of tubular pile, upwards rush out sand and soil along the inner wall of second section tubular pile and first section tubular pile, and supplementary static air compressor machine carries out the pile pressing operation, the efficiency of pile pressing has not only been improved, and effectively avoid the tubular pile bearing capacity to exceed the design requirement, form good guard action to the tubular pile. The diameter of the tail end of the closing-in 3 of the air supply pipe 1 positioned at the lowest end is 0.6-0.7 time of the diameter of the air supply pipe 1; the air supply pipe 1 at the lowest end can be inserted into sediment and clay in a pile hole conveniently, the pipe is not easy to block, the insertion force is large, and the footage speed is high by matching with the vibrator 2.
In this embodiment, the length of the vibrating hole cleaner in the step (2) is matched with the length of the first section of tubular pile; the vibration hole cleaner in the step (4) is additionally connected with an air supply pipe 1 on the basis of the vibration hole cleaner in the step (2), and is matched with the total length of the first section of tubular pile and the second section of tubular pile; and (3) the vibration hole cleaner in the step (6) is additionally connected with the blast pipe 1 on the basis of the vibration hole cleaner in the step (4) and is matched with the total length of the first section of tubular pile, the second section of tubular pile and the third section of tubular pile.
In this embodiment, the inner diameter of the main body of the air supply pipe 1 is 0.22 times of the inner diameter of the first section of tubular pile, the second section of tubular pile or the third section of tubular pile; in the range, the blast pipe 1 is matched with the vibrator 2 for use, and the hole cleaning effect formed by air flow impact is better.
In this embodiment, a circle of upward-inclined vent holes are formed in the wall of each air supply pipe 1, part of air is flushed out from the vent holes obliquely upwards, and sandy soil flushed up by the air supply pipe 1 at the lowest end is assisted to be discharged outwards.
In this embodiment, the diameter of the vent hole is 0.05 times the inner diameter of the main body of the blast pipe 1, and the impact airflow pressure formed by the vent hole is large in this range, and the impact force of the blast pipe 1 at the lowermost end on the sand in the pile hole is not affected.
The construction method in the embodiment only consumes one third of the time of the existing construction method of the pile pressing of the common static pile pressing machine.
The above embodiments are only specific examples of the present invention, and the protection scope of the present invention includes but is not limited to the product forms and styles of the above embodiments, and any suitable changes or modifications made by those skilled in the art according to the claims of the present invention shall fall within the protection scope of the present invention.