CN111519612A - Construction method of full-casing follow-up long spiral drilling pressure-grouting secant pile - Google Patents

Abstract

The invention relates to a construction method of a full pile casing follow-up long spiral drilling pressure-grouting secant pile, which comprises the following steps: s1, positioning and paying off; s2, constructing a guide wall; s3, drilling; s3.1, positioning a drilling machine; s3.2, starting a drilling machine; s4, pouring concrete by pressure; s5, installing a reinforcement cage; the pile hole is arranged in sequence as follows: A1-B1-A2-B2-A3-B3-A4-B4 … An-Bn; after the A1 concrete pressure irrigation is finished, excavating a B1 pile hole immediately; when the A2 pile hole concrete pressure irrigation is completed, installing a reinforcement cage on a B1 pile hole; and when the A3 concrete pressure irrigation is finished, carrying out reinforcement cage installation on the B2 pile holes, and sequentially carrying out reinforcement cage installation on the B-shaped piles. The invention has the advantages of enhancing the stable connection between the A-shaped pile and the B-shaped pile, reducing the generation of cold joints, improving the water stopping effect of the wall body and reducing the water seepage probability while facilitating the construction.

Description

Construction method of full-casing follow-up long spiral drilling pressure-grouting secant pile

Technical Field

The invention relates to the technical field of building foundation construction, in particular to a construction method of a full pile casing follow-up long spiral drilling pressure-grouting secant pile.

Background

The commonly used foundation pit supporting soil-retaining water-stopping structure at present comprises a cast-in-situ bored pile and a water-stopping curtain, an underground continuous wall, an SMW construction method, a bored secant pile and the like. The secant pile is generally formed by secant of a reinforced concrete pile and a plain concrete pile to form a complete wall body and has the functions of soil retaining and water stopping; the existing underground continuous wall is mainly used as a temporary support during construction, the underground continuous wall is withdrawn from a stage after the underground construction is finished and filled back, the function of the underground continuous wall is not considered in the use process of a later building structure, certain waste is caused, the underground continuous wall is used as a structural stress of a main structure participating in a normal use stage, and the important significance is achieved.

The existing Chinese patent with the publication number of CN106400782B discloses a construction method for constructing a foundation pit enclosure drilling secant pile by using a rotary drilling rig, which comprises the following construction steps: 1. construction preparation, namely measuring and placing a pile position on a construction site according to a pile position plane diagram and driving a mark; 2. embedding a pile casing; 3. positioning a drilling machine; 4. mechanical hole forming, namely drilling holes by using a rotary drilling rig, constructing A-shaped piles (plastic concrete plain piles) for every 9 piles in a construction cycle, and constructing B-shaped piles (reinforced concrete piles) between adjacent A-shaped piles after the A-shaped piles are initially set for 7-9 hours; 5. brushing the wall and cleaning the hole; 6. hoisting the reinforcement cage, and inserting the reinforcement cage into the pile hole; 7. and (3) performing concrete pressure irrigation, namely performing concrete pressure irrigation on the inside of the B-shaped pile hole by using a conduit method. The construction sequence is as follows: A1-A3-A5-A2-A4-B1-B2-B3-B4.

The above prior art solutions have the following drawbacks: in the construction process, after the A-shaped piles are initially set for 7-9 hours, drilling is carried out between the adjacent A-shaped piles, in the drilling process, the steel casing is used for cutting off the parts of the two A-shaped piles, and the A-shaped piles are in the initial set state and have higher strength, so that the cutting difficulty of the steel casing is increased, and the drilling efficiency is reduced; on the other hand, when the A-shaped pile is cut by strong force, a certain degree of deviation can be generated in the pile hole, and the bearing capacity of a subsequent pile foundation is influenced; meanwhile, when the B-shaped pile is poured, because the A-shaped pile is initially set, the setting time between the A-shaped pile and the B-shaped pile is inconsistent, so that a cold joint is generated between the A-shaped pile and the B-shaped pile, and the water stopping effect of the wall body is influenced by the generation of the cold joint, and the problem of water seepage possibly occurs subsequently.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a construction method of a full-pile casing follow-up long spiral drilling pressure-filling secant pile, which has the effects of enhancing the stable connection between an A-type pile and a B-type pile, reducing the generation of cold joints, improving the water stop effect of a wall body and reducing the water seepage probability while facilitating construction.

The above object of the present invention is achieved by the following technical solutions:

a construction method for a full pile casing follow-up long spiral drilling pressure-grouting secant pile comprises the following steps:

s1, positioning and paying off, measuring and paying off the pile position on the construction site according to the pile position plane diagram and the site reference point, and driving an obvious mark;

s2, construction of guide wall

S2.1, leveling the field: removing impurities on the surface of the ground, and filling and rolling the groove for the migration of the underground pipeline;

s2.2, pouring guide wall concrete, namely firstly excavating a groove, constructing a reinforcing mesh in the groove, and then pouring concrete;

s2.3, after the concrete is solidified to be of sufficient strength, positioning and lofting the center position of the test pile, and marking the point position above the guide wall;

s3, drilling

S3.1, positioning a drilling machine, and adjusting the verticality of the steel casing and the required pile hole positioning;

s3.2, starting the drilling machine, driving the steel casing and the long spiral drill rod to move downwards, and enabling the long spiral drill rod to rotate automatically to perform drilling and soil taking work;

s4, grouting concrete, after the drill rod drills to the designed depth, starting a concrete delivery pump, delivering the concrete into the pile hole through the long spiral drill rod, and slowly lifting the drill rod while grouting the concrete;

s5, installing a reinforcement cage, and vertically inserting the reinforcement cage into the B-shaped pile hole by using a drilling machine and a vibrator;

the pile hole is arranged in sequence as follows: A1-B1-A2-B2-A3-B3-A4-B4 … An-Bn; after the A1 concrete pressure irrigation is finished, constructing a B1 pile immediately; when the A2 pile hole concrete pressure irrigation is completed, installing a reinforcement cage on a B1 pile hole; and when the A3 concrete pressure irrigation is finished, carrying out reinforcement cage installation on the B2 pile holes, and sequentially carrying out reinforcement cage installation on the B-shaped piles.

By adopting the technical scheme, when the pile foundation is constructed, after the first pile hole is subjected to concrete pressure grouting, the second pile hole can be drilled and taken out immediately, so that when the first concrete pile is still in a fluid state, the first concrete pile can be partially cut off, and the resistance in the drilling process is small, thereby being beneficial to improving the drilling efficiency; secondly, the lateral displacement jacking force on the first concrete pile can be reduced, and the inclination probability of the concrete pile is reduced; thirdly, after the second pile hole is drilled and the soil is taken, when the concrete is filled in the second pile hole, the first concrete pile and the second concrete pile can be better solidified into a whole because the first concrete is still in a fluid state, and cold joints generated between adjacent pile foundations can be reduced, so that the water stop effect after the continuous wall is formed can be enhanced, and the effect of reducing the water seepage probability is achieved;

when the pressure grouting of the concrete of A3 is completed, a steel reinforcement cage can be inserted into the B2 pile hole, on one hand, the concrete in the B2 pile hole still belongs to fluid, so that the insertion work of the steel reinforcement cage is facilitated, and on the other hand, the concrete in the B2 pile hole is extruded in the insertion process of the steel reinforcement cage, so that the concrete in the B2 pile hole is better solidified with the concrete in the A1 and A3 pile holes into a whole.

The present invention in a preferred example may be further configured to: in the step S3.2, the drilling speed of the common soil layer is 1-2 m/min; the drilling speed of the gravel layer is 0.2-0.5 m/min; the formation drilling rate was 0.2 m/min.

By adopting the technical scheme, the drilling speed of the drill rod is changed corresponding to the adaptability of the soil layers made of different materials, the drill bit of the drill rod is protected, and the service life of the drill rod is prolonged.

The present invention in a preferred example may be further configured to: and step S3, when drilling, the lower end of the long auger stem is 1m-1.5m higher than the lower end of the steel casing.

By adopting the technical scheme, the steel casing is firstly inserted into the soil layer to play a role of wall protection, so that the long spiral drill head can conveniently drill and take soil from the soil in the steel casing; meanwhile, the steel casing is used for protecting the wall, so that the wall can be protected without slurry, the steps are simplified, and the construction work of the whole secant pile is facilitated.

The present invention in a preferred example may be further configured to: in step S4, in the process of lifting the drill, the concrete in the long auger stem is not lower than 2m above the ground.

By adopting the technical scheme, the pouring height can be judged according to the sound of concrete poured in the spiral drill rod.

The present invention in a preferred example may be further configured to: in step S5, before inserting the steel reinforcement cage into the pile body concrete, a digging machine is used to dig out the residual soil with the pile top elevation above 30cm, and then the residual soil on the concrete surface layer is manually cleaned.

Through adopting above-mentioned technical scheme, the in-process that long auger stem got soil, soil is piled up in the week side of stake hole top, utilizes the excavator can clear up soil fast, when the pile bolck only remains 30cm soil thickness, causes destruction to the concrete pile for avoiding the excavator, changes to the manual work and clears up soil, reaches the effect that the protection pile foundation pile bolck does not receive the destruction.

Aiming at the defects in the prior art, the invention also aims to provide an auxiliary mechanism which has the effects of conveniently adjusting the verticality of the steel casing and improving the vertical precision of a pile hole, thereby improving the bearing capacity of a pile foundation.

The above object of the present invention is achieved by the following technical solutions:

the auxiliary mechanism comprises a rack, wherein a vertical projection plane of the rack is L-shaped, pushing pieces are arranged on two sides of the L-shaped rack respectively, screw rod transmission pieces driving the pushing pieces to linearly displace are further arranged on the rack respectively, the two pushing pieces are perpendicular to each other, and in the displacement process, the pushing pieces are abutted against the side wall of the steel casing.

By adopting the technical scheme, the bearing capacity of a subsequent pile foundation is greatly influenced by the perpendicularity of the pile hole, and the perpendicularity of the pile hole depends on the perpendicularity of the steel casing and the long auger stem during drilling; because the steel casing is positioned at the outer side of the long spiral drill rod, the perpendicularity of the long spiral drill rod can be synchronously realized by adjusting the perpendicularity of the steel casing; when the steel pile casing and the pile hole datum point are positioned, the rack can be fixed on the guide wall and positioned outside the steel pile casing, when the verticality of the steel pile casing is adjusted, the corresponding screw rod transmission part can be driven to drive the pushing part to move according to the standard of a theodolite, so that the pushing part can be pushed in the moving process, the steel pile casing is pushed, and the two groups of pushing parts are vertically arranged, so that the gradient of different planes of the steel pile casing can be adjusted, the vertical precision of the steel pile casing can be improved, the vertical precision of the pile hole can be ensured, and the bearing capacity of a subsequent pile foundation can be ensured.

The present invention in a preferred example may be further configured to: the screw rod transmission part comprises a screw rod and a guide rod which are connected to the rack and arranged in parallel, the screw rod is rotationally connected to the rack, the screw rod and the guide column respectively penetrate through the pushing part, and the screw rod is in threaded fit with the pushing part; one end of the screw rod, which is far away from the steel casing, extends out of the rack and is fixed with a first hand wheel.

By adopting the technical scheme, the guide rod plays a role in guiding the pushing piece, so that the pushing piece can only make linear displacement, and the linear displacement work of the pushing piece can be realized by the thread matching effect of the screw rod and the pushing piece when the screw rod is driven to rotate by the hand wheel I.

The present invention in a preferred example may be further configured to: the pushing piece comprises a mounting seat, a sliding groove is arranged on the mounting seat along the screw rod in parallel, a pushing rod with one end abutting against the steel casing is inserted in the sliding groove, a displacement block is fixed on one side of the pushing rod in the sliding chute, the displacement block is arranged in an isosceles trapezoid shape, the lower bottom of the displacement block is fixed with the pushing rod, the sliding groove is communicated with an installation channel for the linear displacement of the displacement block, a first transmission block and a second transmission block are respectively arranged on two inclined surfaces corresponding to the displacement block in the installation channel, and the mounting channel is respectively and rotatably connected with a first adjusting screw rod and a second adjusting screw rod which penetrate through the first transmission block and the second transmission block and are in threaded fit with the first transmission block and the second transmission block, the first adjusting screw rod and the second adjusting screw rod are arranged in a way of being vertical to the transmission direction of the pushing rod, and the first displacement block and the second displacement block are abutted against the inclined plane of the isosceles trapezoid in the linear displacement process.

By adopting the technical scheme, when the screw rod is used for transmission and adjustment, the linear displacement distance is larger, the steel casing is longer, and the inclination angle of the whole steel casing is larger due to slight deviation, so that when the inclination angle of the steel casing is adjusted, the rough positioning of the steel casing is adjusted by using the screw rod transmission part; the first transmission block and the second transmission block are driven to synchronously and reversely linearly displace under the matching action of the first adjusting screw and the second adjusting screw with the threads of the first transmission block and the second transmission block respectively, and the first transmission block and the second transmission block are abutted against the inclined surface of the displacement block to drive so as to realize the linear displacement of the push rod, so that the push rod can drive the steel casing to perform fine adjustment work, and the vertical precision of the steel casing is further improved;

meanwhile, the first transmission block and the second transmission block are always in a butting relation with two inclined planes of the displacement block, and can keep limiting action on the displacement block and the push rod, so that the steel casing can be assisted in limiting action, and can move downwards under the guiding action of the push rod after the steel casing is adjusted, and certain deviation caused by the influence of vibration force when the steel casing works on a drilling machine is avoided.

The present invention in a preferred example may be further configured to: the thread directions of the first adjusting screw rod and the second adjusting screw rod are the same, and gears which are meshed with each other are coaxially fixed respectively; one end of the first adjusting screw rod extends out of the mounting seat and is fixed with a second hand wheel.

By adopting the technical scheme, the second hand wheel is driven to drive the first adjusting screw rod to rotate, the second adjusting screw rod can be driven to synchronously and reversely rotate under the action of gear meshing, and simultaneously, the first adjusting screw rod and the second adjusting screw rod have the same thread direction, so that the synchronous reverse displacement of the first transmission block and the second transmission block can be realized.

In conclusion, the beneficial technical effects of the invention are as follows:

1. during pile foundation construction, after concrete pressure grouting is carried out on a first pile hole, drilling and soil taking can be carried out on a second pile hole at once, so that when a first concrete pile is still in a fluid state, the first concrete pile can be partially cut off, and firstly, the resistance force applied in the drilling process is small, and the drilling efficiency is improved; secondly, the lateral displacement jacking force on the first concrete pile can be reduced, and the inclination probability of the concrete pile is reduced; thirdly, after the second pile hole is drilled and the soil is taken, when the concrete is filled in the second pile hole, the first concrete pile and the second concrete pile can be better solidified into a whole because the first concrete is still in a fluid state, and cold joints generated between adjacent pile foundations can be reduced, so that the water stop effect after the continuous wall is formed can be enhanced, and the effect of reducing the water seepage probability is achieved;

2. when the concrete pressure irrigation of the A3 is completed, a steel reinforcement cage can be inserted into the B2 pile hole, on one hand, the concrete in the B2 pile hole also belongs to fluid, so that the insertion work of the steel reinforcement cage is facilitated, and on the other hand, the concrete in the B2 pile hole is extruded in the insertion process of the steel reinforcement cage, so that the concrete in the B2 pile hole is better solidified with the concrete in the A1 and A3 pile holes into a whole, and the water stop effect between adjacent pile foundations is further enhanced;

3. when adjusting the straightness that hangs down of a steel casing, can order about corresponding lead screw driving medium and drive the impeller displacement according to the standard of theodolite, make its impeller displacement in-process, push away the steel casing, because the top pushes away the piece and sets up two sets ofly perpendicularly, the different planar gradient of adjustable steel casing helps improving the vertical precision of a steel casing to can guarantee the vertical precision in stake hole, guarantee the bearing capacity of follow-up pile foundation.

Drawings

FIG. 1 is a schematic view of the construction flow of example 1;

FIG. 2 is a schematic view of a drilling sequence of embodiment 1;

FIG. 3 is a schematic view of the entire structure of embodiment 2;

FIG. 4 is a schematic cross-sectional view of the pusher member of FIG. 3;

fig. 5 is an enlarged schematic view at a in fig. 4.

In the figure, 1, a reinforcement cage; 2. a long auger stem; 3. a steel casing; 4. a power head; 5. a frame; 6. a screw rod transmission part; 61. a screw rod; 62. a guide bar; 63. a first hand wheel; 7. a pusher member; 71. a mounting seat; 72. a chute; 73. a push rod; 74. a displacement block; 75. adjusting the channel; 76. a first transmission block; 77. a second transmission block; 78. a first inclined plane; 79. a second inclined plane; 710. a first guide post; 711. a second guide post; 712. a gear; 713. a second hand wheel; 714. adjusting a first screw rod; 715. and adjusting the screw rod II.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1: referring to fig. 1 and 2, the invention discloses a construction method of a full casing follow-up long spiral drilling pressure-grouting secant pile, which comprises the following steps:

and S1, positioning and paying off, measuring and paying off the pile position at the construction site according to the pile position plane diagram and the site reference point, and driving an obvious mark.

S2, construction of guide walls:

s2.1, leveling the field: removing impurities on the surface of the ground, and filling and rolling the groove for the migration of the underground pipeline; in the implementation, if a miscellaneous filling soil layer influencing pore forming is encountered, a method for replacing plain soil is adopted, and after the guide wall is manufactured, the soil layer in the pores is tamped, so that the steel casing 3 is in place correctly;

s2.2, pile position measuring and placing: and (4) adopting a total station to perform field lofting according to the ground lead control point, marking and using the marked point as a control center line of guide wall construction.

S2.3, excavating a guide wall groove: after the paying-off of the pile position meets the requirement, the groove can be excavated, after the excavation, the central line is led under the groove, the construction of the bottom die and the template is controlled, and the central line of the guide wall is ensured to be correct;

s2.4, binding steel bars: binding guide wall reinforcing steel bars after the trench excavation is finished;

s2.5, template construction: the template adopts the self-made whole steel mould, leads the wall and reserves the location hole template diameter and expand 10 ~ 20mm for the sleeve pipe diameter. The template is reinforced by steel pipes, the supporting distance is not more than 1.0m, and the reinforcement is firm and the template is prevented from running strictly; the accuracy of the axis and the clearance is ensured, and before concrete pouring, whether the verticality, the center line and the clearance of the template meet the requirements is checked;

s2.6, pouring guide wall concrete: and when concrete is poured, the two sides are symmetrically and alternately carried out, and the mould is strictly prevented from moving. And if the formwork walking occurs, immediately stopping pouring of concrete, reinforcing the formwork again, correcting to the required position, and then continuing pouring. The vibrating adopts an inserted vibrator, the vibrating distance is about 600mm, the non-uniform vibrating is prevented, and the phenomenon of mold walking caused by over-vibration at one position is also prevented;

and S2.7, when the guide wall has enough strength, removing the template, repositioning the center of the lofting test pile, and reflecting the point position to the top surface of the guide wall to serve as a drilling machine positioning control point.

S3, the drilling sequence of this embodiment is: A1-B1-A2-B2-A3-B3-A4-B4 … An-Bn; wherein, the A-shaped pile is a plastic concrete plain pile, and the B-shaped pile is a reinforced concrete pile.

S4, positioning a drilling machine:

s4.1, rechecking the pile position again before the construction and positioning of the drilling machine, and marking a clear cross control line by using a reinforcing steel bar head to mark the center of a guide wall hole position;

s4.2, after the guide wall reaches a certain strength, moving the drilling machine, correspondingly positioning the drill bit cone top at the center of the guide wall hole site, aligning the cone top with the center of the guide wall hole site, slowly lowering the drill rod until the steel wire rope of the hanging power head 4 is not stressed any more, and inserting the drill bit into the ground;

s4.3, after the drilling machine is in place, firstly adjusting the positions of the left and right ship boards to stabilize the drilling machine, then adjusting the front and rear ship boards to stabilize the drilling machine, and then adjusting the verticality of the drilling rod by utilizing the inclined support rods; in this embodiment, the verticality deviation of the drill rod is not greater than 1/300.

S5, drilling

S5.1, firstly, a lower power head 4 is used for pressing down a steel casing 3 to a certain depth, then the lower power head 4 is used for driving the steel casing 3 to drill, the penetration depth of a drill bit of a long spiral drill rod 2 is guaranteed to be about 1m higher than the bottom of the steel casing 3, the upper power head 4 is driven to follow the long spiral drill rod 2, and the steel casing 3 and the drill rod drill simultaneously until the drill reaches the designed elevation; wherein, when the reinforced concrete pile is constructed, the drilling depth of the steel pile casing 3 must be more than 300mm deeper than the pile bottom of the plain concrete pile.

S5.2, starting a large winch when drilling is started, enabling a steel wire rope to bear a slight force, slowly drilling at a low rotating speed, enabling the earth surface to be a general stable soil layer, and drilling at a high rotating speed after a drill bit is buried for 1-2 m; in areas where old foundations or obstacles may be encountered, after ensuring the depth of the obstacle, rapid drilling may be used;

s5.3, generally, the drilling speed of the soil layer is preferably 1-2 m/min, the drilling speed of the gravel layer is preferably 0.2-0.5 m/min, the particle size of the gravel is small, the drilling speed is reduced to be below 0.2 m/min after the gravel enters the rock stratum, and a rock-entering drill bit is installed in advance according to the strength of the rock stratum.

S6, concrete is grouted under pressure, after each pile hole is drilled and the soil is taken to the designed depth, the concrete is grouted under pressure to the current pile hole immediately:

s6.1, starting a concrete delivery pump, performing pressure filling on concrete, after the long spiral drill pipe 2 is filled, slowly lifting the drill pipe, performing continuous pressure filling on the concrete, lifting the drill pipe after the concrete in the drill pipe exceeds the ground height, wherein the concrete in the drill pipe is higher than the ground by more than 2m during continuous drilling lifting, and judging the filling height through the sound of the falling of the concrete in the drill pipe.

S6.2, during the continuous pouring of the pile body concrete, the depth of the drill bit embedded into the concrete is preferably 1-2m, the drill bit and the drill rod are prevented from being embedded too deeply, the concrete is wasted, the drill bit and the reinforcement cage 1 are prevented from being inserted easily, the pumping integrated equipment is adopted to control the drill lifting speed and the concrete pouring amount, and the drill lifting speed is guaranteed to be matched with the concrete pouring amount. And (3) synchronously lifting the drill rod and the steel protective cylinder 3 during concrete pressure irrigation, keeping the drill bit higher than the bottom of the steel protective cylinder 3 by 2m, and slowly lifting the steel protective cylinder 3 after the concrete is pressure-irrigated to the position above the guide wall surface until the steel protective cylinder 3 is completely pulled out.

S7, inserting the reinforcement cage 1, and installing the reinforcement cage 1 in the B1 pile hole when the A2 pile hole concrete pressure irrigation is completed; when the A3 concrete pressure irrigation is finished, installing reinforcement cages 1 in B2 pile holes, and sequentially installing reinforcement cages 1 of B-shaped piles;

s7.1, cleaning the residual soil on the pile top: before the steel reinforcement cage 1 is inserted into the pile body concrete, excavating residual soil above the elevation of the pile top, after the residual soil above the pile top by about 30cm is reserved, manually cleaning the residual soil of a concrete surface layer, and exposing the complete pile body section concrete;

s7.2, hoisting the reinforcement cage 1: when the length of the steel reinforcement cage 1 exceeds 12m, a small lifting hook is adopted to hang the middle part of the steel reinforcement cage 1, the vibrator and the steel reinforcement cage 1 are lifted slowly, a lifting rope in the middle part is stressed synchronously, so that the bending deformation of the steel reinforcement cage 1 in the lifting process can be avoided, the bottom of a steel reinforcement is stabilized by manpower, the ground sundries are prevented from being dragged, the top of the steel reinforcement cage 1 is pulled by the manpower by a rope, and the vibrator can be prevented from hanging or colliding with the rack 5 and a drill rod;

s7.3, loading into a guiding device: after the reinforcement cage 1 is hung straight, the reinforcement cage 1 is placed in a guide sleeve of the reinforcement cage 1, and the guide sleeve is lifted to the height range of the reinforcement 2/3.

S7.4, inserting a reinforcement cage 1: hold reinforcing bar cage 1 with the manual work and aim at the interior concrete of stake, make reinforcing bar cage 1 protective layer all around unanimous, slowly insert in the concrete, prevent to scrape the pore wall, the uide bushing follows downwards, adopts the dead weight of reinforcing bar cage 1 and vibrator earlier to sink, uses the vibration to sink reinforcing bar cage 1 again, until pile bolck design elevation place.

S7.5, after the steel reinforcement cage 1 is inserted, protecting pile top concrete, and after the concrete is naturally solidified, not burying the concrete immediately.

And S8, curing after pile forming, and inspecting.

In the process of the step of drilling in S5: and judging the condition of entering the entry layer according to the data of the test pile and the geological exploration report and the change of the current value of the drilling machine in the drilling process. When the pile is long or the friction (side) resistance of the soil around the pile is large, the total current value is increased due to the fact that the resistance of the whole-course spiral piece of the long spiral drill rod 2 is increased, the rock entering condition is determined by combining the swinging working state of the drilling machine, and the drilling machine continuously swings when contacting with the rock stratum due to the fact that the rock stratum is harder than the soil stratum. And after the concrete pouring is finished and the drill rod is pulled out, taking out the drill bit and rock sample for confirmation, referring to the data during pile testing, and if the rock sample does not accord with the geological report, re-drilling (re-driving the pile) the pile until the pile enters the bearing stratum.

Meanwhile, when the pile is formed by one-time drilling and pressure filling, the drill rod is not suitable to be reversed or lifted in the drilling process, and the condition that the drill head is damaged due to the fact that a drill head cover is opened, underground water and soil enter the drill head and the quality of pressure filling concrete is influenced is avoided.

In this embodiment, the protection measures for the finished product are as follows:

1. during the manufacturing, transportation and installation processes of the reinforcement cage 1, measures for preventing deformation should be taken. When the pile is placed into a pile hole, a protective cushion block or a cushion pipe and a cushion plate are bound.

2. During construction, when the machines move and hoist the steel reinforcement cage 1 or press-pour concrete and the like, the axis control net and the level foundation point pile on the site are protected well.

3. The main rib dowel reserved on the pile top is properly protected and cannot be bent or broken randomly.

4. The excavation of the soft soil foundation pit with the piles is finished, reasonable construction sequence and technical measures are formulated to prevent the piles from shifting and inclining, and the longitudinal and transverse horizontal deviation of each pile is checked to take corrective measures.

5. The cast-in-place pile just poured can not be rolled. Jump excavation construction should be adopted on site to prevent deformation or fracture of the pile and the like caused by vibration or lateral extrusion of soil.

In the traditional construction process, according to the drilling sequence of A1-A2-B1-A3-B2-A4-B3, cutting construction of a reinforced concrete pile is carried out after the construction of a plain concrete pile is completed for 6-8 hours, and the pile-forming time of 20 meters of pile length is about 90 minutes; the construction method of the secant pile of the embodiment is to perform secant cutting before the initial setting of the plain concrete, and the pile forming time of 20 meters of pile length is about 40 minutes.

Example 2: referring to fig. 3, an auxiliary mechanism for adjusting the position of the steel casing 3 in the construction of the interlocking pile; the device comprises a rack 5, wherein the vertical projection plane of the rack 5 is L-shaped, pushing pieces 7 are respectively arranged on two sides of the upper end of the rack 5, and the two pushing pieces 7 are mutually perpendicular; referring to fig. 4 and 5: the pushing member 7 comprises a mounting seat 71 mounted on the frame 5 (refer to fig. 3), the mounting seat 71 is provided with a sliding groove 72 along the radial direction of the steel casing 3, a pushing rod 73 is inserted in the sliding groove 72, a displacement block 74 is fixed on one side of the pushing rod 73 positioned in the sliding groove 72, the lower bottom of the displacement block 74 is in isosceles trapezoid shape fixed with the pushing rod 73, and two side surfaces of the displacement block 74 along the transmission direction of the pushing rod 73 are an inclined surface one 78 and an inclined surface two 79; an adjusting channel 75 communicated with the sliding groove 72 is formed in the mounting seat 71, and the displacement block 74 is positioned in the adjusting channel 75 and can linearly displace along with the push rod 73; a first transmission block 76 and a second transmission block 77 are further arranged in the adjusting channel 75, the side walls of the first transmission block 76 and the second transmission block 77 are abutted against the side wall of the adjusting channel 75, and are respectively abutted against a first inclined surface 78 and a second inclined surface 79 of the displacement block 74, and the first transmission block and the second transmission block are arranged along the plane perpendicular to the straight line of the push rod 73 in a staggered manner in an initial state; the adjusting channel 75 is further rotatably connected with a first adjusting screw 714 and a second adjusting screw 715 respectively, the first adjusting screw 714 and the second adjusting screw 715 are perpendicular to the pushing rod 73, penetrate through the first transmission block 76 and the second transmission block 77 respectively, and are in threaded fit with the first transmission block 76 and the second transmission block 77 respectively. In this embodiment, the first adjusting screw 714 and the second adjusting screw 715 have the same thread direction, and are coaxially fixed with gears 712 engaged with each other, wherein one end of the first adjusting screw 714 extends to the outside of the mounting seat 71, and the other end is coaxially fixed with a second handwheel 713. When the second hand wheel 713 drives the first adjusting screw 714 to rotate, the second adjusting screw 715 is driven to synchronously rotate in the reverse direction, so that the first transmission block 76 and the second transmission block 77 perform synchronous reverse linear displacement, and under the abutting relation with the first inclined surface 78 and the second inclined surface 79 of the displacement block 74, the linear displacement of the push rod 73 is realized, so that the push rod 73 pushes the side wall of the steel casing 3, and the verticality of the steel casing 3 is adjusted.

In this embodiment, in order to ensure stable linear displacement of the first transmission block 76 and the second transmission block 77, a first guide post 710 and a second guide post 711 which are parallel to the first adjustment screw 714 are further fixed on the side wall of the adjustment channel 75, and through holes for the first guide post 710 and the second guide post 711 to pass through are respectively formed in the first transmission block 76 and the second transmission block 77.

Referring to fig. 3, the rack 5 is further provided with a lead screw transmission member 6 for driving the mounting seat 71 to linearly displace, the lead screw transmission member 6 includes a lead screw 61 and a guide rod 62 which are arranged in parallel, the lead screw 61 is rotatably connected to the rack 5, the guide rod 62 is fixed on the rack 5, and the lower end of the mounting seat 71 is respectively provided with a through hole for the guide rod 62 to pass through and a threaded hole for the lead screw 61 to pass through and be matched with the lead screw 61; one end of the screw rod 61, which is far away from the steel casing 3, extends out of the rack 5, and a first hand wheel 63 is coaxially fixed at the end; and in the process that the first hand wheel 63 drives the screw rod 61 to rotate, the radial displacement of the mounting seat 71 along the steel casing 3 is realized.

The implementation principle of the embodiment is as follows: when the steel casing 3 is positioned, the steel casing 3 is firstly detected to incline towards which side according to the theodolite, and then the frame 5 is placed on the inclined side of the steel casing 3 and fixed on the guide wall; the lead screw 61 is driven to rotate by the first hand wheel 63 to drive the mounting seat 71 to linearly displace, the lower end of the steel casing 3 is driven to deflect by the push rod 73, the inclination angle of the steel casing 3 is roughly adjusted, then the second hand wheel 713 is driven to rotate to drive the first adjusting screw 714 and the second adjusting screw 715 to rotate, the first transmission block 76 and the second transmission block 77 are driven to obliquely push the displacement block 74, the push rod 73 is driven to linearly displace, accurate adjustment of the steel casing 3 is achieved, and the verticality of the steel casing 3 is maintained to the maximum extent.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims (9)

1. A construction method for a full pile casing follow-up long spiral drilling pressure-grouting secant pile comprises the following steps:

s1, positioning and paying off, measuring and paying off the pile position on the construction site according to the pile position plane diagram and the site reference point, and driving an obvious mark;

s2, constructing a guide wall;

s2.1, leveling the field: removing impurities on the surface of the ground, and filling and rolling the groove for the migration of the underground pipeline;

s2.2, pouring guide wall concrete, namely firstly excavating a groove, constructing a reinforcing mesh in the groove, and then pouring concrete;

s2.3, after the concrete is solidified to be of sufficient strength, positioning and lofting the center position of the test pile, and marking the point position above the guide wall;

s3, drilling

S3.1, positioning a drilling machine, and adjusting the verticality of the steel casing (3) and the required pile hole positioning;

s3.2, starting the drilling machine, driving the steel protective cylinder (3) and the long spiral drill rod (2) to displace downwards, and simultaneously enabling the long spiral drill rod (2) to rotate to perform drilling and soil taking work;

s4, concrete is grouted under pressure, after the drill rod drills to the designed depth, the concrete delivery pump is started, the concrete is delivered into the pile hole through the long spiral drill rod (2), and the drill rod is lifted slowly while the concrete is grouted under pressure;

s5, installing the reinforcement cage (1), and vertically inserting the reinforcement cage (1) into the B-shaped pile hole by using a drilling machine and a vibrator;

the method is characterized in that: the pile hole is arranged in sequence as follows: A1-B1-A2-B2-A3-B3-A4-B4 … An-Bn; after the A1 concrete pressure irrigation is finished, constructing a B1 pile immediately; when the A2 pile hole concrete pressure irrigation is completed, installing a reinforcement cage (1) in a B1 pile hole; and when the A3 concrete pressure irrigation is finished, installing the reinforcement cage (1) in the B2 pile hole, and sequentially installing the reinforcement cage (1) of the B-shaped pile.

2. The construction method of the full casing follow-up long spiral drilling pressure-filling occlusive pile according to claim 1, characterized by comprising the following steps: in the step S3.2, the drilling speed of the common soil layer is 1-2 m/min; the drilling speed of the gravel layer is 0.2-0.5 m/min; the formation drilling rate was 0.2 m/min.

3. The construction method of the full casing follow-up long spiral drilling pressure-filling occlusive pile according to claim 1, characterized by comprising the following steps: and step S3, when drilling, the lower end of the long auger stem (2) is 1m-1.5m higher than the lower end of the steel casing (3).

4. The construction method of the full casing follow-up long spiral drilling pressure-filling occlusive pile according to claim 1, characterized by comprising the following steps: in the step S4, in the drill lifting process, the concrete in the long auger stem (2) is not lower than 2m of the ground.

5. The construction method of the full casing follow-up long spiral drilling pressure-filling occlusive pile according to claim 1, characterized by comprising the following steps: in the step S5, before the reinforcement cage (1) is inserted into the pile body concrete, a digging machine is used for digging out the residual soil with the pile top elevation more than 30cm, and then the residual soil on the concrete surface layer is manually cleaned.

6. An auxiliary mechanism for the construction method of a steel casing occlusive pile according to any one of claims 1 to 5, characterized in that: the steel pile casing structure is characterized by comprising a rack (5), wherein the vertical projection plane of the rack (5) is L-shaped, pushing pieces (7) are respectively arranged on two sides of the L-shaped rack (5), screw rod transmission pieces (6) for driving the pushing pieces (7) to linearly displace are respectively arranged on the rack (5), the two pushing pieces (7) are perpendicular to each other, and are abutted against the side wall of the steel pile casing (3) in the displacement process.

7. An assist mechanism as claimed in claim 6, wherein: the screw rod transmission piece (6) comprises a screw rod (61) and a guide rod (62) which are connected to the rack (5) and arranged in parallel, the screw rod (61) is rotationally connected to the rack (5), the screw rod (61) and the guide column respectively penetrate through the pushing piece (7), and the screw rod (61) is in threaded fit with the pushing piece (7); one end, far away from the steel casing (3), of the screw rod (61) extends out of the rack (5) and is fixed with a first hand wheel (63).

8. An assist mechanism as claimed in claim 6, wherein: the pushing piece (7) comprises an installation base (71), sliding grooves (72) are formed in the installation base (71) in parallel along a screw rod (61), a push rod (73) with one end abutted to the steel casing (3) is inserted in the sliding grooves (72), a displacement block (74) is fixed to one side, located in the sliding grooves (72), of the push rod (73), the displacement block (74) is arranged in an isosceles trapezoid mode, the lower bottom of the displacement block is fixed to the push rod (73), the sliding grooves (72) are communicated with an installation channel for linear displacement of the displacement block (74), a first transmission block (76) and a second transmission block (77) are arranged in the installation channel and correspond to two inclined planes of the displacement block (74), and a first adjusting screw (714) and a second adjusting screw (714) are rotatably connected in the installation channel and penetrate through the first transmission block (76), the second transmission block (77) and are in threaded fit with the first transmission block (76) and the second transmission block (77, And the first adjusting screw (714) and the second adjusting screw (715) are arranged perpendicular to the transmission direction of the push rod (73), and the first displacement block (74) and the second displacement block (74) are abutted to the inclined plane of the isosceles trapezoid in the linear displacement process.

9. An assist mechanism as claimed in claim 8, wherein: the thread directions of the first adjusting screw rod (714) and the second adjusting screw rod (715) are the same, and gears (712) which are meshed with each other are coaxially fixed respectively; one end of the adjusting screw rod I (714) extends out of the mounting seat (71) and is fixed with a hand wheel II (713).

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