Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a construction device of the cast-in-situ concrete core cement-soil mixing pile, which has the advantages of reasonable structure, convenient construction, reliable quality and economy.
The technical problems of the invention are realized by the following technical scheme:
the construction equipment of a kind of cast-in-situ concrete core cement mixing pile, it is a multi-functional cement mixing pile machine, it includes fuselage, lifting rope, power head and hollow structural drilling rod, there are grouting tube groups to blowout cement paste to the bottom of drilling rod in the drilling rod, the external surface of the drilling rod has stirring pieces, the stirring piece is driven by the drilling rod to rotate and mix and stir cement paste and soil mass and form the cement mixing pile in the soft soil layer; the drill rod consists of an upper drill rod and a lower drill rod which are connected with each other; the lower drill rod is internally provided with a movably sleeved corrugated pipe, the bottom end of the lower drill rod is provided with a drill bit, and the top surface of the drill bit is fixed at the lower end of the corrugated pipe in a sealing way and is in airtight contact with the bottom end of the lower drill rod; the top of the lower drill rod is provided with a fastening component for detachably mounting the corrugated pipe and the drill bit in the lower drill rod; the top end of the upper drill rod is connected with a power head, and a water injection pipe for injecting water into the corrugated pipe is arranged in the upper drill rod; after the cement mixing pile is formed, the corrugated pipe and the drill bit are synchronously reserved in the center of the cement mixing pile, and a concrete core is cast in situ in the corrugated pipe.
When the drill rod starts to ascend and the corrugated pipe is left in the cement soil mixing pile, the corrugated pipe is subjected to the combined action of cement soil and water pressure, and the strength of the corrugated pipe is calculated by a formula I; the second formula calculates that the corrugated pipe is deformed at the moment, the gap between the outer wall of the corrugated pipe and the inner wall of the drill rod is also changed, the first formula and the second formula are used as the basis for selecting the material and the size of the corrugated pipe, and the first formula and the second formula are as follows:
equation one,
Formula II,
,
Then
In the first formula and the second formula
-pressure of water and soil cement against the bottom section of the bellows, < - > a->;
The effective length of the corrugated pipe embedded in the cement mixing pile, namely the water injection height of the corrugated pipe, < ->;
-volume weight of water, jersey>;
-volume weight of cement soil, < - > j->;
The lateral pressure coefficient before the initial setting of the cement soil is dimensionless, and is determined by a test, and 0.4 to 0.6 is taken when no test data exists;
-hoop tension applied to the bellows circular section, +.>;
-calculated radius of bellows, +.>;
-the angle between any point of the circumference of the circular section of the bottom surface of the bellows and the horizontal axis, +.>;
-hoop tensile stress on the bellows bottom circular section, +.>Wherein 1 is the unit height, < >>;
-bellows circular section calculation wall thickness, < >>;
-the bellows ring section material is tolerant of tensile stress, < ->;
-calculating the perimeter of the bellows bottom section, +.>;
-calculated perimeter elongation of the bellows bottom section under the pressure of water and soil cement, < ->;
-calculated radius of bellows, +.>;
-the bellows bottom section calculates the radius increment under the pressure of water and soil cement,/->,/>The increase of (2) possibly pressing the inner wall of the drill rod, the proper clearance between the outer diameter of the corrugated pipe and the drill rod, the wall thickness of the corrugated pipe and the elastic modulus parameters are selected, and the increment of the calculated radius of the corrugated pipe is not increased +.>The increase of the diameter of the corrugated pipe is 2 mm-4 mm, which is used for clamping the drill rod to influence the retention of the corrugated pipe;
the expansion increment of the bottom section of the corrugated pipe in the circumferential direction unit perimeter under the pressure action of water and cement soil is dimensionless, namely strain;
-modulus of elasticity of bellows, < >>;
Wave-shapeDesign allowance of the radius increment of the bellows calculation, < +.>。
The fastening component comprises a pull rod arranged in the corrugated pipe, the lower end of the pull rod is detachably connected to the drill bit, and the upper end of the pull rod is provided with a pull rod ring; the upper end of the corrugated pipe is provided with a pull rod bolt which horizontally passes through the pull rod ring, the pull rod, the corrugated pipe and the drill bit are integrated, and the two ends of the pull rod bolt respectively pass through and are arranged in a chute which vertically extends from the side wall of the lower drill rod; the lower drill rod is externally provided with a hoop which is detachably and tightly attached to the lower part of the pull rod bolt, the hoop is tightly held outside the lower drill rod, and the lifting and moving positions of the two ends of the pull rod bolt in the sliding groove are positioned.
The upper drill rod bottom and the lower drill rod top between be equipped with interconnect's flange, two the spout set up in the flange below on lower drill rod top to the axle center of lower drill rod sets up on the lateral wall of lower drill rod as central symmetry, the vertical extension length of every spout is 1~ 2mm, the width is greater than the diameter of pull rod bolt 1mm ~2mm, the both ends of this pull rod bolt are done lift along the spout and are removed, and drive bellows and drill bit and do synchronous lift in lower drill rod.
The pull rod is a steel round rod and is arranged at the axle center of the lower drill rod and the corrugated pipe, the lower end of the pull rod is provided with a pull rod bolt which is detachably connected to the drill bit, and the pull rod ring is an integrally formed round ring at the upper end of the pull rod.
The pull rod bolt is a steel round rod, one end of the pull rod bolt is nut-shaped, the other end of the pull rod bolt is provided with a bolt hole, and after sequentially penetrating through the chute on one side of the lower drill rod, the pull rod ring and the chute on the other side of the lower drill rod, the bolt is inserted into the bolt hole for temporary fixation.
The anchor ear is formed by connecting left and right semicircular plates in a butt joint way, wing plates are arranged on the left and right semicircular plates, and fastening bolts for holding the anchor ear are arranged on the wing plates.
Compared with the prior art, the invention mainly designs a multifunctional cement mixing pile machine, which is characterized in that a drill rod of the cement mixing pile machine is formed by adopting an upper drill rod and a lower drill rod which are connected with each other, and a corrugated pipe and a drill bit are detachably arranged in the lower drill rod through a fastening component to form an integral part. Therefore, through the cement mixing pile machine with novel structure, the construction of the cement mixing pile and the stiff core pile can be completed at one time only by one cement mixing pile machine, the quality of the cement mixing pile formed by mixing is not affected, the coagulation forming of the cement is not disturbed, the cement is not pushed to cause the non-uniformity of the cement, and the cement mixing pile machine has the advantages of reasonable structure, convenience in construction, reliable quality, economy and the like.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the drawings.
1-6, 1.soft soil layer, 2.cement mixing piles, 3.cast-in-place concrete core, 4.corrugated pipe, 41.exhaust hole, 5.cement mixing pile machine, 51.fuselage, 52.lifting rope, 53.power head, 54.locating clamp, 55.drill pipe, 551.upper drill pipe, 552.lower drill pipe, 553.flange, 56.stirring blade, 57.drill bit, 58.pull rod, 581.pull rod ring, 582.pull rod bolt, 583.pull rod bolt, 584.plug, 585.water injection pipe, 59.grouting pipe group, 591.vertical grouting pipe, 592.annular grouting pipe, 593.grouting head, 6.anchor ear and 61.chute.
The construction device is shown in figure 1, and concretely relates to a multifunctional cement mixing pile machine, wherein a cement mixing pile 2 is a main agent which uses cement as a curing agent and is an effective form of soft foundation treatment, and cement slurry is sprayed into soil by using the cement mixing pile machine 5 and fully mixed, so that the cement and soft soil are subjected to a series of physical and chemical reactions, and the soft soil is hardened into cement soil to improve the foundation strength.
The multifunctional cement mixing pile machine consists of a machine body 51, a lifting rope 52, a power head 53, a positioning clamp 54, a drill rod 55 with a hollow structure, a grouting pipe group 59 which is arranged in the drill rod and ejects cement paste to the bottom end of the drill rod, a mixing blade 56 which is arranged on the outer surface of the drill rod 55, and the like.
The main body 51 is a main supporting and moving part of the cement mixing pile machine 5; the lifting rope 52 is a steel wire rope, one end of the lifting rope is connected with the winch of the machine body 51, the other end of the lifting rope is wound around the pulley block at the top of the machine body to suspend the power head 53, the upper end of the drill rod 55 is vertically arranged at the bottom of the power head 53, and the power head 53 and the drill rod 55 are driven to move up and down through the lifting rope 52 by winding or releasing the winch, so that the stirring and grouting sinking and rising effects of the cement stirring pile machine 5 are achieved.
The power of the power head 53 has the functions of rotation and vibration, and is also a power source for the operation of parts such as the drill rod 55, and the drill rod 55 can be driven to rotate when sinking and rising; when the reserved corrugated pipe 4 ascends after the cement mixing pile 5 is sprayed, the vibration driving drill rod 55 overcomes the cohesive force of the soft soil of the mixing pile, and meanwhile, the damage of the mixing piece 56 to the pile body of the cement mixing pile 2 is reduced or avoided.
The positioning clamp 54 is a rigid component for connecting the machine body 51 and the drill rod 55, the height and the horizontal position of the positioning clamp 54 can be adjusted before the drill rod is positioned, and once the drill rod 55 is accurately positioned, the drill rod can horizontally rotate and vertically move up and down in the positioning clamp 54.
The stirring plate 56 is a sheet-shaped steel structure for stirring soft soil, and is fixed on the outer circumferential surface of the lower part of the drill rod 55 by various shapes, lengths and plum blossom shapes, and when the drill rod rotates, the stirring plate 56 rotates to stir the soft soil, so that the stirring plate is uniformly mixed with cement paste sprayed into the soft soil layer 1, and the cement soil stirring pile 2 is formed.
The corrugated pipe 4 and the drill bit 57 are arranged in the drill pipe 55, and after the construction of the cement-soil mixing pile 2 is completed and the drill pipe 55 is lifted, the corrugated pipe can be synchronously remained in the center of the cement-soil mixing pile 2 and the concrete core 3 can be cast in situ, so that a stiff core pile with much higher strength and rigidity than the cement-soil mixing pile is formed.
The drill rod 55 is a steel hollow pipe and consists of an upper drill rod 551 and a lower drill rod 552, the top end of the upper drill rod 551 is connected with a power head 53, a water injection pipe 585 is arranged in the upper drill rod 551, one end of the water injection pipe is exposed from the side wall of the drill rod 55 and is communicated with a water pump, the other end of the water injection pipe 585 is positioned above the corrugated pipe 4 and can be used for injecting water into the corrugated pipe, and the bottom end of the upper drill rod 551 is provided with a flange 553; the top end of the lower drill rod 552 is also provided with a flange 553, so the upper drill rod 551 and the lower drill rod 552 are connected through the flange 553; the bellows 4 is movably sleeved in the lower drill rod 552, and the drill bit 57 is arranged at the bottom end of the lower drill rod 552.
The corrugated pipe 4 is a double-wall hollow pipe with an outer wall and a smooth inner wall of an annular structure formed by hot melt extrusion, and the outer diameter of the double-wall hollow pipe is 2-4 mm smaller than the inner diameter of a drill rod, wherein Polyethylene (PE) or polypropylene (PP) or high-density polyethylene (HDPE) is used as a main raw material; the side wall of the top of the corrugated pipe is provided with the vent hole 41 shown in fig. 5 for exhausting when the water is injected into the corrugated pipe 4, so that after the water is injected into the corrugated pipe 4, the corrugated pipe can be prevented from being extruded and deformed by the cement-soil mixing pile 2 which is not initially set, the downward gravity of the corrugated pipe 4 can be increased, and the situation that the corrugated pipe 4 and the drill bit 57 are difficult to keep in the rising process of the drill pipe 55 is avoided; the corrugated pipe 4 can also adopt a steel band reinforced polyethylene spiral corrugated pipe, and when the single length is insufficient, the connection modes of hot melt extrusion welding, electric melting band connection, shrinkage pipe connection, clamping hoop and the like specified by the current standards can be adopted.
The drill bit 57 is funnel-shaped and made of the same material as the corrugated pipe 4, the bottom end of the lower drill rod 552 is tightly and closely contacted with the top surface of the drill bit 57 as shown in fig. 4 without water leakage, and the lower end of the corrugated pipe 4 is bonded, sealed and fixed with the top surface of the drill bit 57 by epoxy resin to play a role in sealing the corrugated pipe 4, so that water is not leaked when water is injected into the corrugated pipe; when the cement mixing pile 2 is completed and the corrugated pipe 4 is left after the drill pipe 55 is pulled out, the drill bit 57 and the corrugated pipe 4 are synchronously left in the cement mixing pile 2 to serve as the cast-in-situ concrete core 3.
When the drill rod 55 starts to ascend to leave the corrugated pipe 4 in the cement mixing pile 2, the strength of the corrugated pipe 4 is calculated by a formula I under the combined action of cement and water pressure; the second formula calculates that the bellows 4 is deformed at this time, the gap between the outer wall of the bellows and the inner wall of the drill pipe 55 is also changed, and the first and second formulas are used as the basis for selecting the material and the size of the bellows 4, and the formulas are as follows:
equation one,
Formula II,
,
Then
In the first formula and the second formula
-pressure of water and cement soil against the bottom section of bellows 4, +.>;
The effective length of the bellows 4 embedded in the cement mixing pile 2, i.e. the height of the bellows 4 filled with water,/->;
-volume weight of water, jersey>;
-volume weight of cement soil, < - > j->;
The lateral pressure coefficient before the initial setting of the cement soil is dimensionless, and is determined by a test, and 0.4 to 0.6 is taken when no test data exists;
-hoop tension exerted on the circular section of bellows 4->;
-calculated radius of bellows 4, +.>;
-the angle between any point of the circumference of the circular section of the bottom surface of the bellows 4 and the horizontal axis, +.>;
-the hoop tensile stress to which the bellows 4 base ring section is subjected, +.>Wherein 1 is the unit height, < >>;
-calculating the wall thickness of the bellows 4 circular section, < >>;
-the bellows 4 circular section material allows for tensile stress, +.>;
-bellows 4 bottom section calculation perimeter, +.>;
-calculated perimeter elongation of the bottom section of bellows 4 under the pressure of water and soil cement, < ->;
-calculated radius of bellows 4, +.>;
-the bottom section of bellows 4 calculates the radius increment under the pressure of water and soil cement,/->,/>The increase of (2) possibly squeezes the inner wall of the drill rod 55, and the appropriate gap between the outer diameter of the corrugated pipe 4 and the drill rod 55, the wall thickness of the corrugated pipe 4 and the elastic modulus parameter are selected, so that the increment of the calculated radius of the corrugated pipe is avoided>The increase of the diameter of the corrugated pipe 4 is 2 mm-4 mm, which is used for clamping the drill rod 55 to influence the retention of the corrugated pipe;
the expansion increment of the circumferential unit perimeter of the bottom section of the corrugated pipe 4 under the pressure action of water and cement soil is dimensionless, namely strain;
-modulus of elasticity of bellows 4 +.>;
-bellows 4 calculate the design allowance of the radius increment,/->。
The cement slurry in the soft soil layer 1 is mainly sprayed out from a grouting pipe group 59 in the drill pipe 55 to the bottom end of the drill pipe 55, and the grouting pipe group 59 comprises two vertical grouting pipes 591 symmetrically fixed on the outer wall of the drill pipe 55 and an annular grouting pipe 592 arranged at the bottom end of the drill pipe 55 and positioned above the drill bit 57; the upper end of the vertical grouting pipe 591 is externally connected with curing agent conveying pumps such as cement paste, the lower end of the vertical grouting pipe 591 is communicated with an annular grouting pipe 592, 3-4 symmetrically distributed grouting heads 593 are arranged on the annular grouting pipe, and the curing agent conveying pumps can spray cement paste from the grouting heads 593 through the grouting pipe group 59.
The lower drill rod 552 has a fastening unit at its top for detachably mounting the bellows 4 and the drill bit 57 in the lower drill rod 552, and the fastening unit is mainly composed of a tie rod 58, a tie rod bolt 583, a hoop 6, and the like as shown in fig. 2 and 3.
The pull rod 58 is a steel round rod and is arranged at the axes of the lower drill rod 552 and the corrugated pipe 4, the lower end of the pull rod 58 is detachably connected with the drill bit 57 through a pull rod bolt 582, and the upper end of the pull rod 58 is an integrally formed round pull rod ring 581.
The pull rod bolts 583 are steel round rods and are arranged at the upper end of the corrugated pipe 4, one end of each pull rod bolt is nut-shaped, bolt holes are formed in the other end of each pull rod bolt, two sliding grooves 61 are formed in the side wall below the flange 553 at the top end of the lower drill rod 552, the two sliding grooves are symmetrically arranged by taking the axis center of the lower drill rod 552 as the center, the vertical extension length of each sliding groove 61 is 1-2 m, the width of each sliding groove is 1-2 mm larger than the diameter of the pull rod bolt 583, the pull rod bolts are inserted from the sliding groove 61 at one side of the lower drill rod 552, then horizontally penetrate through the pull rod rings 581 and then penetrate out from the sliding groove 61 at the other side of the lower drill rod 552, bolts 584 are inserted into the bolt holes to be temporarily fixed, and then the pull rod 58, the corrugated pipe 4 and the drill bit 57 are formed into a whole through the pull rod bolts 583, and the two ends of the pull rod bolts 583 are just located in the two sliding grooves 61.
The hoop 6 is detachably attached to the outside of the lower drill rod 552 at the lower part of the pull rod bolt 583, the hoop 6 is tightly attached to the outside of the lower drill rod 552, the lifting and moving positions of the two ends of the pull rod bolt 583 in the sliding groove 61 are positioned, the hoop 6 is formed by joining two left and right semi-circular hoops after being joined, the wing plates of the hoop 6 are provided with fastening bolts, and the hoop can be tightly fixed on the lower drill rod 552 after being tightly held, so that the pull rod 58, the pull rod bolt 583, the corrugated pipe 4 and the drill bit 57 are temporarily fixed. When the anchor ear 6 is detached, both ends of the pull rod bolt 583 can move up and down in the sliding groove 61, and the bellows 4 and the drill bit 57 are driven to move up and down synchronously in the lower drill rod 552.
Therefore, the construction device can cast-in-situ concrete core 3 in the concrete mixing pile 2, in order to ensure that the axial force of the pile end of the cast-in-situ concrete core can be sufficiently diffused when being transmitted to a bearing layer through the cement mixing pile 2, the cast-in-situ concrete core 3 with high strength can not pierce the bottom end of the cement mixing pile 2, the length of the cast-in-situ concrete core 3 is 1 m-1.5 m shorter than that of the cement mixing pile, the ratio of the diameter of the cast-in-situ concrete core to the diameter of the cement mixing pile is not less than 0.3, the thickness of the cement covered by the cast-in-situ concrete core is not less than 120mm, the length-width ratio of the cast-in-situ concrete core is not more than 80, and the cast-in-situ concrete core is formed by directly pouring cement concrete, and a reinforcement cage can be configured according to requirements.
The examples of the present invention are only for illustrating the present invention and are not intended to limit the scope of the present invention. It is also to be understood that various changes and modifications may be made by one skilled in the art after reading the teachings of the invention, and such equivalents are intended to fall within the scope of the claims appended hereto.