CN111519613A - Construction method of test pile with ultra-buried depth in rock stratum - Google Patents

Construction method of test pile with ultra-buried depth in rock stratum Download PDF

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Publication number
CN111519613A
CN111519613A CN202010380207.1A CN202010380207A CN111519613A CN 111519613 A CN111519613 A CN 111519613A CN 202010380207 A CN202010380207 A CN 202010380207A CN 111519613 A CN111519613 A CN 111519613A
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China
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pile
drilling
concrete
sleeve
hole
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CN111519613B (en
Inventor
王伟
董福永
张串
王安平
葛群
汪兆斌
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Second Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
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Second Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/34Concrete or concrete-like piles cast in position ; Apparatus for making same
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D13/00Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers
    • E02D13/04Guide devices; Guide frames
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D13/00Accessories for placing or removing piles or bulkheads, e.g. noise attenuating chambers
    • E02D13/08Removing obstacles
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D33/00Testing foundations or foundation structures
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/66Mould-pipes or other moulds
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B11/00Other drilling tools
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/10Geometric CAD
    • G06F30/13Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads

Abstract

The invention discloses a construction method of a test pile with ultra-buried depth in a rock stratum, belonging to the field of test pile construction, aiming at solving the technical problems that the complex rock stratum which is often encountered by a cast-in-place pile is difficult to form a hole, the underwater concrete ultra-filling elevation cannot be accurately controlled, the static load detection operation condition at the bottom of an ultra-deep foundation pit is limited, and the friction resistance is controlled to influence the bearing detection, and the technical scheme is as follows: the method comprises the following steps: s1, construction preparation; s2, performing advanced drilling exploration, and establishing a rock surface BIM model; s3, positioning and embedding the pile casing, and manufacturing and placing the double sleeves of the test pile; s4, positioning a drilling machine, and adjusting the centering and verticality of a drill rod; s5, drilling in soil layers, protecting walls and drilling in terrane multi-stage steps; s6, monitoring the verticality of the drill rod by using an internal and external double control method; s7, manufacturing the reinforcement cage and installing an anti-floating structure according to the step 2, hoisting the reinforcement cage and installing an over-irrigation monitoring probe; s8, placing a guide pipe, and cleaning holes for the second time by adopting a gas lift reverse circulation method; and S9, underwater concrete pouring and super-pouring height monitoring.

Description

Construction method of test pile with ultra-buried depth in rock stratum
Technical Field
The invention relates to the field of test pile construction before building foundation excavation, in particular to a construction method of a test pile with ultra-buried depth in a rock stratum.
Background
The test pile is a test testing device used before building construction, and aims to detect whether the bearing capacity and the settlement of the pile foundation conform to the design so as to ensure the building construction quality. The test pile is generally carried out before the excavation of a building foundation pit or before the excavation reaches the elevation of the bottom of the pit.
With the increasing of large-scale super high-rise and underground space construction projects, the foundation burial depth is also increased continuously, and the number of similar projects is increased more and more. Accordingly, the embedding depth of the pile top is also increased continuously, and engineering piles with the embedding depth of 25m are common. For the ground-operated super-buried depth cast-in-place pile, the depth of the empty pile above the effective pile body is larger, and particularly for the short pile pier in the rock stratum, the length of the empty pile can be more than 5 times of the length of the effective pile.
For a test pile embedded deeply at the pile top in a rock stratum, a pile body needs to be extended to the ground for detection, large friction force is formed in an empty pile section to influence accurate detection of bearing capacity of the test pile, the tonnage of detection loading can be increased, and when the tonnage of loading exceeds 30000KN, field implementation is difficult. Moreover, for large-diameter cast-in-place piles in complex rock formations, the problems of inaccurate rock surface judgment, difficult control of concrete casting height, steel bar floating cages, easy damage of drill bits after rock entering, pile hole verticality deviation and the like exist. Therefore, the technical problems that the complex rock stratum is difficult to form holes, the underwater concrete super-irrigation elevation cannot be accurately controlled, the static load detection operation condition at the bottom of the ultra-deep foundation pit is limited, and the bearing detection is influenced by the control of the frictional resistance are solved.
Disclosure of Invention
The technical task of the invention is to provide a construction method of a test pile for ultra-buried depth in a rock stratum, which solves the problems that a bored pile is difficult to form a hole in a complex rock stratum, underwater concrete ultra-grouting elevation cannot be accurately controlled, static load detection operation conditions at the bottom of an ultra-deep foundation pit are limited, and bearing detection is influenced by control of frictional resistance.
The technical task of the invention is realized in the following way, the construction method of the test pile with ultra burial depth in the rock stratum adopts a double-sleeve structure, utilizes an outer sleeve to resist the pressure of the soil layer, takes the inner sleeve as a concrete outer mold, isolates the frictional resistance of the pile body of the hollow pile part, and realizes the accurate detection of the bearing capacity of the effective pile body before the excavation of the deep foundation pit; constructing a rock stratum information model by utilizing the soil layer parameters obtained by the multiple advanced drills by utilizing the BIM technology, and predetermining the pile length; then, automatically acquiring technical parameters in the underwater concrete pouring process by using a monitoring probe, processing data, dynamically monitoring the height of poured concrete, and realizing braking alarm prompt and commanding pouring operation by using a preset limit value; the method comprises the following specific steps:
s1, construction preparation;
s2, performing advanced drilling exploration, and establishing a rock surface BIM model;
s3, positioning and embedding the pile casing, and manufacturing and placing the double sleeves of the test pile;
s4, positioning a drilling machine, and adjusting the centering and verticality of a drill rod;
s5, drilling in soil layers, protecting walls and drilling in terrane multi-stage steps;
s6, monitoring the verticality of the drill rod by an internal and external double control method, and completing slag salvaging and hole cleaning at the bottom of a hole and hole forming acceptance inspection;
s7, manufacturing the reinforcement cage and installing an anti-floating structure according to the step 2, hoisting the reinforcement cage and installing an over-irrigation monitoring probe;
s8, placing a guide pipe, and cleaning holes for the second time by adopting a gas lift reverse circulation method;
s9, pouring underwater concrete and monitoring the super-pouring height, and pouring the underwater concrete to the super-pouring height;
s10, recovering the sensor probe and the signal wire.
Preferably, in the step S2, the advance drilling exploration is performed, and the building of the rock surface BIM model is specifically as follows:
s201, aiming at the fluctuant rock surface, one column and one pileThe pile is explored by adopting five-hole advanced drilling; wherein, the distribution of five holes is that a center hole is arranged at the center of the pile, and the other four holes are distributed in a circle by taking the center hole as the center of the circle;
aiming at a common pile, carrying out one pile of porous exploration;
s202, building a pile foundation rock layer BIM model and an engineering geology BIM model according to exploration technical parameters, and drawing a single-pile rock face condition model;
and S203, determining the pile length according to the design requirements according to the elevation and the physical properties of the rock stratum.
Preferably, the positioning and embedding of the casing in step S3 is as follows:
s301-1, measuring and placing a pile position by using a total station, and marking by using a mark pile; taking a pile position as a center, leading out four pile casing control points in four directions, leading the control points to be 1.0 time of the pile diameter from the center point of the pile position, and preparing a control pile;
s301-2, aligning the center of a drill bit to a pile core mark pile, excavating pile core soil (namely pile casing depth), burying a pile casing according to a control pile, and enabling the distance between the outer wall of the pile casing and the four control piles to be equal to enable the center of the pile casing to coincide with the center of a pile position.
Preferably, the manufacturing and installation of the double sleeve of the test pile in the step S3 are as follows:
s302-1, manufacturing a double sleeve: the inner sleeve and the outer sleeve are both threaded welded pipes made of 20mm steel plates and are made of Q345B; the outer sleeve has the diameter of (D +400) mm and the length of (H +300) mm and is used for resisting the soil body pressure; the inner sleeve is (D +200) mm in diameter and (H +300+1500) mm in length and serves as a concrete pouring template, and the two ends of the outer side of the inner sleeve, within the range of 2.5m, are wrapped with oil-immersed cotton felt and are fixed in an anti-sliding manner; wherein D represents the diameter of the test pile; h represents the depth of the foundation pit;
s302-2, placing of a double sleeve: drilling the outer sleeve to the elevation of the bottom of the foundation pit, and hoisting and fixing the outer sleeve; drilling a hole in the inner sleeve to penetrate into the pit bottom for 1m, and hoisting and fixing the inner sleeve; the construction process specifically comprises the following steps:
(1) drilling a pile hole with the diameter of (D +400) mm to the elevation of the bottom of the foundation pit;
(2) hoisting and fixing the outer sleeve;
(3) drilling a pile hole with the diameter of (D +200) mm to penetrate into the bottom of the foundation pit by 1.0 m;
(4) the two ends of the inner sleeve are wrapped with the oil-impregnated cotton felt within 2.5 m;
(5) hoisting and placing a fixed inner sleeve;
(6) drilling a pile hole with the diameter of D to the bottom of the pile;
(7) and performing subsequent construction of the cast-in-place pile.
Preferably, in the step S4, the drilling machine is in place, and the drill rod centering and verticality adjusting method specifically comprises the following steps:
s401, before the drilling machine is in place, the site is required to be processed to be smooth and firm so as to meet the construction verticality requirement, and after the drilling machine is in place according to the specified position, the verticality of a mast and a drill rod needs to be adjusted under the guidance of a technician;
s402, when the hole positions are aligned, the hole positions are aligned by adopting a cross method;
s403, after the hole positions are aligned, starting a positioning system to perform positioning memory;
s404, after the hole is centered, the drilling machine cannot be shifted, and the angle of the drill arm cannot be changed randomly.
Preferably, the soil layer drilling and the wall protection in the step S5 are specifically as follows:
s501, before drilling, measuring the top elevation of the hole protecting cylinder by using a level gauge so as to control the drilling depth;
s502, when the drilling starts, paying attention to the drilling speed and adjusting the drilling speeds of different stratums;
s503, in the drilling process, keeping the mud surface not lower than the top of the protective cylinder by 400 mm;
s504, during drilling lifting, slurry is timely supplemented into the hole to keep the slurry surface not lower than the top of the protective cylinder by 400 mm;
s505, in the drilling process, observing and checking at any time by using an engineering detection ruler, and adjusting and controlling the verticality of the drill rod;
in the step S5, the rock stratum multi-stage step drilling is carried out according to the height of a drilling bucket, the vertical height of a step is 2m, the width of the step is 200mm, and the difference between the width of the step and the diameter is 400 mm.
Preferably, in step S6, the verticality monitoring of the drill rod by using the internal and external dual control method includes the following specific steps:
s601, strictly controlling the verticality of the drill rod according to the standard, wherein the verticality of the drill rod is controlled according to 0.5%;
s602, reading the verticality of a drill rod in real time by an instrument panel in a cab of the rotary drilling rig, and carrying out internal control by an operator according to the reading of the instrument;
s603, adopting a theodolite by a manager to carry out external control in two directions; when the theodolite tracks and monitors to find out the verticality deviation, the 2mm guiding rule is adopted to accurately measure the verticality deviation, and the problem is found and adjusted in time.
Preferably, the manufacturing of the reinforcement cage and the installation of the anti-floating structure according to step 2 in step S7 are as follows:
add the anti structure that floats of welding in the bottom of steel reinforcement cage, anti structure that floats adopts the steel sheet to weld into the cross, and two steel sheet cross welding of 500mm wide 150mm of length put at steel reinforcement cage bottom central point, and no language pipe mouth below 250mm department, the buoyancy of concrete to the steel reinforcement cage is resisted to the pressure that produces when the concrete is poured.
Preferably, the hoisting of the reinforcement cage and the installation of the super irrigation monitoring probe in the step S7 are as follows:
s701, placing a reinforcement cage into a pile hole by adopting a crawler crane, and installing a concrete over-irrigation monitoring probe at the upper end of the reinforcement cage when the upper end of the reinforcement cage is close to the hole opening, and fixing the reinforcement cage by using a special buckle;
s702, the probe is lowered along with the steel reinforcement cage and is connected with ground equipment through a data line, and the length of the data line is determined according to the depth of the pile hole;
s703, before concrete pouring, debugging equipment, and determining the upper limit of the concrete height, wherein the operation steps are as follows:
firstly, lowering the top end of a reinforcement cage to the height of an orifice;
secondly, mounting a monitoring probe and a data line;
connecting and debugging equipment;
fourthly, setting upper and lower limits of the designed elevation;
fifthly, pouring concrete;
sixthly, monitoring dynamic curve fluctuation through a mobile phone or a computer, and adjusting the supply amount of concrete according to the actual concrete pouring height;
seventhly, the curve is raised to the upper limit, namely the concrete is raised to the height exceeding the upper limit;
and (8) dismantling the recovery probe and the data line (finishing the perfusion).
Preferably, the underwater concrete pouring and super-pouring height monitoring in the step S9 is specifically as follows:
s901, before concrete is poured into a hopper, firstly, closing the hopper opening by using a plug until the hopper is full, and after the next car of concrete is in place, pulling the plug open by using a crane auxiliary hook;
s902, instantly pouring concrete into the pile bottom, enabling the slurry surface to rise and overflow the pile hole;
s903, starting a slurry pump, and delivering slurry to a slurry storage pool;
s904, placing the first concrete on the concrete surface all the time, and jacking from bottom to top; the remarks are as follows:
the whole pouring process ensures the control of the fluidity time of the first poured concrete, and the concrete cannot stay for 2 hours in a field; controlling the slump at 180-220 mm;
in the whole pouring process, the guide pipe is always kept 2-6m below the concrete surface, and a specially-assigned person should command and control the guide pipe when the guide pipe is lifted, so that the inclination and the displacement of the steel bar framework are avoided;
and thirdly, in the pouring process, monitoring the elevation of the concrete surface at any time by using a monitoring instrument, and strictly controlling the height of the over-poured concrete to be 800-1000mm, so as to ensure the effective pile length and the height of the pile head.
The construction method of the test pile for the ultra-buried depth in the rock stratum has the following advantages:
the invention improves the construction process, adopts new equipment and new software, combines BIM technology application, solves a plurality of problems encountered by similar pile foundation engineering, and has great popularization and application values in the aspects of improving the quality of a test pile, ensuring the accuracy of a detection result, ensuring safe production, accelerating the construction speed, reducing the economic cost and the like;
the invention adopts the double-sleeve to isolate the pressure of the side soil of the pile, eliminates the construction technology of the frictional resistance of the empty pile, solves the difficulties of ultra-buried depth in the rock stratum, no static load detection condition at the bottom of the pit and large bearing capacity of perfusion static load detection, avoids the detection error caused by a conversion deduction method, can provide accurate technical parameters for the design, and can reduce the loading weight during the detection; the double sleeves comprise outer sleeves and inner sleeves, the principle that the outer sleeves resist the pressure of a soil layer and the inner sleeves serve as concrete outer molds is utilized to isolate the frictional resistance of the pile body of a hollow pile part, the bearing capacity of the effective pile body is accurately detected before the deep foundation pit is excavated, and the difficulty of a large-tonnage static load test is solved;
the invention applies the technology of building the BIM rock surface model by the porous advanced drill, solves the problem that the rock surface elevation cannot be accurately judged due to rock surface fluctuation, accurately and intuitively masters the underground rock layer distribution condition in the field before construction, thereby not only being beneficial to ensuring the pile bottom elevation and the pile length, prefabricating a reinforcement cage in advance, improving the quality acceleration progress, but also being beneficial to the accurate accounting of the engineering quantity of drilling into rock and earthwork;
the construction technology realizes the informatization monitoring of the underwater concrete pouring height through the monitoring probe, acquires information in the underwater concrete pouring process through the monitoring probe pre-embedded on the reinforcement cage, analyzes the concrete pouring height by using software, tracks and monitors the concrete pouring height, forms a dynamic curve, automatically alarms after reaching preset limits, realizes the accurate control of the concrete supply amount and the pouring height, ensures the pile top elevation and reduces the concrete loss.
Step drilling technology is adopted for large-diameter bored concrete piles in the rock stratum, so that the problem of insufficient torque of equipment is solved, the construction progress is accelerated, the equipment loss is reduced, and the hole forming quality is improved;
according to the self-balancing anti-floating structure of the reinforcement cage, the self-weight of the concrete and the reinforcement cage is utilized to offset the buoyancy of the concrete, the stress balance of the reinforcement cage is realized, the problem of the floating cage of the cast-in-place pile is solved, and the floating phenomenon of the reinforcement cage is avoided;
the gap between the outer sleeve and the inner sleeve adopts flexible filler, so that friction is reduced, and the inner sleeve and the outer sleeve can be concentric; the double-sleeve construction process adopts the inner sleeve and the outer sleeve to be installed twice, or can be realized by prefabricating and assembling the double sleeves according to field conditions and hoisting the double sleeves into the holes once; according to the invention, two ends of the double sleeve are sealed by adopting flexible materials, and the upper end of the double sleeve is provided with the annular cover plate, so that the double sleeve is stronger in implementation and better in effect.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a flow chart of a construction method of a test pile with ultra-buried depth in a rock stratum;
FIG. 2 is a schematic plan view of a pile foundation rock formation exploration layout;
FIG. 3 is a schematic perspective view of a BIM model of a subterranean formation;
FIG. 4 is a schematic cross-sectional view of a mono-pile formation;
FIG. 5 is a diagram of a test pile double sleeve construction;
FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5
FIG. 7 is a flow chart of a test pile double-sleeve construction process;
FIG. 8 is a flow chart of a bench drilling construction process for a test pile with a diameter of 2.8 m;
FIG. 9 is a schematic view of the installation of a monitoring probe;
FIG. 10 is a schematic view of a concrete super irrigation monitoring curve.
In the figure: 1. inner sleeve, 2, outer sleeve, 3, filling layer (oil-immersed cotton felt), 4, annular cover plate, 5, support ear plate, 6, sealing cover plate, 7, signal conductor, 8, pile hole, 9, steel reinforcement cage, 10, sensor probe, 11, buckle.
Detailed Description
The construction method of the ultra-buried depth test pile in the rock stratum is described in detail with reference to the attached drawings and specific embodiments.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description. And are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example (b):
the invention discloses a construction method of an in-rock ultra-buried depth test pile, which is shown in the attached figure 1 and adopts a double-sleeve structure, wherein an outer sleeve is used for resisting the pressure of a soil layer, an inner sleeve is used as a concrete outer mold, the friction resistance of a part of a pile body of a hollow pile is isolated, and the bearing capacity of the effective pile body is accurately detected before a deep foundation pit is excavated; constructing a rock stratum information model by utilizing the soil layer parameters obtained by the multiple advanced drills by utilizing the BIM technology, and predetermining the pile length; then, automatically acquiring technical parameters in the underwater concrete pouring process by using a monitoring probe, processing data, dynamically monitoring the height of poured concrete, and realizing braking alarm prompt and commanding pouring operation by using a preset limit value; the method comprises the following specific steps:
s1, construction preparation; the specific requirements are as follows:
s101, according to design specifications and site conditions, technical preparation work of scheme compilation, approval and background communication is well done;
s102, preparing resources of mechanical equipment, engineering materials, construction machines and labor force according to the scheme requirements;
s103, preparing site preparation work of tee joint leveling, sewage discharge and protection of production facilities and peripheral facilities;
s2, performing advanced drilling exploration, and establishing a rock surface BIM model; the method comprises the following specific steps:
s201, aiming at the fluctuant rock surface, one column and one pileThe pile is explored by adopting five-hole advanced drilling; wherein, the distribution of five holes is that a center hole is arranged at the center of the pile, and the other four holes are distributed in a circle by taking the center hole as the center of the circle, as shown in figure 2;
aiming at a common pile, carrying out one pile of porous exploration;
s202, building a pile foundation rock layer BIM model and an engineering geology BIM model according to exploration technical parameters, and drawing a single-pile rock face condition model as shown in an attached figure 3; wherein, the section of the single pile rock stratum is schematically shown in figure 4;
and S203, determining the pile length according to the design requirements according to the elevation and the physical properties of the rock stratum.
S3, positioning and embedding the pile casing, and manufacturing and placing the double sleeves of the test pile; wherein, the positioning and embedding pile casing is as follows:
s301-1, measuring and placing a pile position by using a total station, and marking by using a mark pile; taking a pile position as a center, leading out four pile casing control points in four directions, leading the control points to be 1.0 time of the pile diameter from the center point of the pile position, and preparing a control pile;
s301-2, aligning the center of a drill bit to a pile core mark pile, excavating pile core soil (namely pile casing depth), burying a pile casing according to a control pile, and enabling the distance between the outer wall of the pile casing and the four control piles to be equal to enable the center of the pile casing to coincide with the center of a pile position.
As shown in fig. 5 and 6, the manufacturing and installation of the double sleeve of the test pile are as follows:
s302-1, manufacturing a double sleeve: the double-sleeve comprises an inner sleeve 1, an outer sleeve 2 is sleeved outside the inner sleeve, a filling layer 3 is arranged between the inner sleeve 1 and the outer sleeve 2, and the filling layer 3 is made of oil-immersed cotton felt. An annular cover plate 4 is welded at the upper end of the inner sleeve 1, and a supporting lug plate 5 is welded on the annular cover plate 4. The upper end of the outer sleeve 2 is provided with a sealing cover plate 6, and the sealing cover plate 6 is connected with the inner sleeve 1 in a welding way and is provided with a stiffening rib plate; the sealing cover 6 has a size of 12 × 300 × circumference. The inner sleeve 1 and the outer sleeve 2 are both threaded welded pipes made of 20mm steel plates and made of Q345B; the outer sleeve 2 has the diameter of (D +400) mm and the length of (H +300) mm and is used for resisting the soil body pressure; the inner sleeve 1 is (D +200) mm in diameter and (H +300+1500) mm in length and serves as a concrete pouring template, and the two ends of the outer side of the inner sleeve 1, within the range of 2.5m, are wrapped with oil-immersed cotton felt and are fixed in an anti-sliding mode; wherein D represents the diameter of the test pile; h represents the depth of the foundation pit;
s302-2, placing of a double sleeve: drilling the outer sleeve 2 to the elevation of the bottom of the foundation pit, and hoisting and fixing the outer sleeve 2; drilling a hole in the inner sleeve 1 to penetrate into the pit bottom 1m, and hoisting and fixing the inner sleeve 1; as shown in the attached figure 7, the construction process specifically comprises the following steps: drilling a pile hole with the diameter of D +400mm to the bottom elevation of the foundation pit, hoisting the fixed outer sleeve 2 → drilling a pile hole with the diameter of D +200mm to penetrate into the bottom of the foundation pit by 1.0m → the inner sleeve 1 is used for wrapping the oil-impregnated cotton felt → hoisting the fixed inner sleeve 1 → drilling a pile hole with the diameter of D to the bottom of the pile → carrying out subsequent construction of a cast-in-place pile.
S4, positioning a drilling machine, and adjusting the centering and verticality of a drill rod; the method comprises the following specific steps:
s401, before the drilling machine is in place, the site is required to be processed to be smooth and firm so as to meet the construction verticality requirement, and after the drilling machine is in place according to the specified position, the verticality of a mast and a drill rod needs to be adjusted under the guidance of a technician;
s402, when the hole positions are aligned, the hole positions are aligned by adopting a cross method;
s403, after the hole positions are aligned, starting a positioning system to perform positioning memory;
s404, after the hole is centered, the drilling machine cannot be shifted, and the angle of the drill arm cannot be changed randomly.
S5, drilling in soil layers, protecting walls and drilling in terrane multi-stage steps; wherein, soil layer drilling, dado are specifically as follows:
s501, before drilling, measuring the top elevation of the hole protecting cylinder by using a level gauge so as to control the drilling depth;
s502, when the drilling starts, paying attention to the drilling speed and adjusting the drilling speeds of different stratums;
s503, in the drilling process, keeping the mud surface not lower than the top of the protective cylinder by 400 mm;
s504, during drilling lifting, slurry is timely supplemented into the hole to keep the slurry surface not lower than the top of the protective cylinder by 400 mm;
s505, in the drilling process, observing and checking at any time by using an engineering detection ruler, and adjusting and controlling the verticality of the drill rod;
because the pile hole is too big, if the drill bit of the rotary drilling rig enters the rock and the drill bucket with large diameter is directly adopted to drill the hole at one time, the diamond bit is seriously damaged, the torque of the drilling rig is far exceeded, and the drill rod cannot rotate. Therefore, rock stratum multi-stage step drilling is adopted, the vertical height of the step is 2m, the width of the step is 200mm, and the difference between the width of the step and the diameter is 400mm according to the height of a drilling bucket. As shown in fig. 8, toThe pile is taken as an example, and the concrete implementation steps are as follows: the diameter of the drill bucket with the diameter of 1.2m is drilled into a rock with the diameter of 6m → the diameter of the drill bucket with the diameter of 1.6m is drilled into the rock with the diameter of 4m → the diameter of the drill bucket with the diameter of 2.0m is drilled into the rock with the diameter of 4m → the diameter of the drill bucket with the diameter of 2m is drilled into the pile bottom with the diameter of 2.8m → the diameter of the drill bucket with the diameter of 1.2m is drilled into the pile bottom with the diameter of 1.6m → the diameter of the drill bucket with the diameter of 2.0m is drilled into the pile bottom with the diameter of 2..
S6, monitoring the verticality of the drill rod by an internal and external double control method, and completing slag salvaging and hole cleaning at the bottom of a hole and hole forming acceptance inspection; because the engineering pile is buried to 26m, if the verticality of the drill rod is controlled to be 1% according to the specification, the pile position deviation reaches 260mm when the positioning deviation is not considered, the allowable deviation of the pile position is 100+ 260-360 mm according to the specification, and larger eccentric bearing is formed. If the verticality in the process is not strictly controlled, larger eccentric stress can be caused. The concrete measures of internal and external double control adopted in the construction process are as follows:
s601, strictly controlling the verticality of the drill rod according to the standard, wherein the verticality of the drill rod is controlled according to 0.5%;
s602, reading the verticality of a drill rod in real time by an instrument panel in a cab of the rotary drilling rig, and carrying out internal control by an operator according to the reading of the instrument;
s603, adopting a theodolite by a manager to carry out external control in two directions; when the theodolite tracks and monitors to find out the verticality deviation, the 2mm guiding rule is adopted to accurately measure the verticality deviation, and the problem is found and adjusted in time.
S7, manufacturing the reinforcement cage and installing an anti-floating structure according to the step 2, hoisting the reinforcement cage and installing an over-irrigation monitoring probe; wherein, the preparation of steel reinforcement cage and anti structure installation of floating are specifically as follows:
the depth of the pile hole reaches 33m, but the pile length is only 4-5m, the weight of the reinforcement cage is light, and the floating cage phenomenon is easy to generate in the underwater concrete pouring process. In order to prevent the floating cage, an anti-floating structure is additionally welded at the bottom end of the steel reinforcement cage, the anti-floating structure is formed by welding steel plates into a cross shape, the two steel plates with the length of 500mm and the width of 150mm are welded into a cross shape, the cross shape is welded at the center of the bottom of the steel reinforcement cage, the position below a silent guide pipe port is 250mm, and the pressure generated during concrete pouring resists the buoyancy of concrete to the steel reinforcement cage.
The concrete steps of hoisting the reinforcement cage and installing the super irrigation monitoring probe are as follows:
s701, placing a reinforcement cage 9 into a pile hole 8 by adopting a crawler crane, installing a concrete over-irrigation monitoring sensor probe 10 at the upper end of the reinforcement cage 9 when the upper end of the reinforcement cage is close to the hole opening, and fixing the concrete over-irrigation monitoring sensor probe by using a buckle 11 as shown in the attached drawing 9;
s702, the probe is lowered along with the steel reinforcement cage and is connected with ground equipment through a signal wire 7, and the length of the signal wire 7 is determined according to the depth of the pile hole 8;
s703, before concrete pouring, debugging equipment, and determining the upper limit of the concrete height, wherein the operation steps are as follows: the top end of the steel reinforcement cage 9 is lowered to the height of the orifice → the sensor probe 10 and the signal lead 7 are installed and monitored → the connecting and debugging equipment → the upper and lower limits of the designed elevation are set → the concrete is poured → the dynamic curve fluctuation is monitored by a mobile phone or a computer, the supply amount of the concrete is adjusted according to the actual concrete pouring height → the curve rises to the upper limit, namely the concrete is raised to the height exceeding → the sensor probe 10 and the signal lead 7 are dismantled and recovered (the pouring is finished).
S8, placing a guide pipe, and cleaning holes for the second time by adopting a gas lift reverse circulation method;
s9, pouring underwater concrete and monitoring the super-pouring height, and pouring the underwater concrete to the super-pouring height as shown in the attached drawing 10; the method comprises the following specific steps:
s901, before concrete is poured into a hopper, firstly, closing the hopper opening by using a plug until the hopper is full, and after the next car of concrete is in place, pulling the plug open by using a crane auxiliary hook;
s902, instantly pouring concrete into the pile bottom, enabling the slurry surface to rise and overflow the pile hole;
s903, starting a slurry pump, and delivering slurry to a slurry storage pool;
s904, placing the first concrete on the concrete surface all the time, and jacking from bottom to top; the remarks are as follows:
the whole pouring process ensures the control of the fluidity time of the first poured concrete, and the concrete cannot stay for 2 hours in a field; controlling the slump at 180-220 mm;
in the whole pouring process, the guide pipe is always kept 2-6m below the concrete surface, and a specially-assigned person should command and control the guide pipe when the guide pipe is lifted, so that the inclination and the displacement of the steel bar framework are avoided;
and thirdly, in the pouring process, monitoring the elevation of the concrete surface at any time by using a monitoring instrument, and strictly controlling the height of the over-poured concrete to be 800-1000mm, so as to ensure the effective pile length and the height of the pile head.
S10, recovering the sensor probe and the signal wire.
In the application of the program in the Baoan people hospital, the invention popularizes and applies the innovative technology to the pile foundation construction, reduces the loss of concrete and reinforcing steel bar raw materials by 2 percent, reduces the loss of equipment, diamond bit and diesel oil by 20 percent, advances the construction period by 78 days, and saves 428 ten thousand of cost. The innovative technology of the invention is applied to the project of a cool building, the construction period is advanced by 32 days, and the cost is saved by 162 ten thousand yuan. The innovation technology of the invention is applied to Shenzhen Wu-mine financial mansion project, the construction period is shortened by 38 days, and the cost is saved by 208 ten thousand yuan.
The invention creates a brand-new construction process and a technical method for the construction of similar projects, fully embodies the demonstration function of building science and technology development based on project entities, and has good social benefit.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A construction method for a test pile with ultra burial depth in a rock stratum is characterized in that a double-sleeve structure is adopted, an outer sleeve is used for resisting soil layer pressure, an inner sleeve is used as a concrete outer mold, the friction resistance of a pile body of a hollow pile part is isolated, and the bearing capacity of an effective pile body is accurately detected before a deep foundation pit is excavated; constructing a rock stratum information model by utilizing the soil layer parameters obtained by the multiple advanced drills by utilizing the BIM technology, and predetermining the pile length; then, automatically acquiring technical parameters in the underwater concrete pouring process by using a monitoring probe, processing data, dynamically monitoring the height of poured concrete, and realizing braking alarm prompt and commanding pouring operation by using a preset limit value; the method comprises the following specific steps:
s1, construction preparation;
s2, performing advanced drilling exploration, and establishing a rock surface BIM model;
s3, positioning and embedding the pile casing, and manufacturing and placing the double sleeves of the test pile;
s4, positioning a drilling machine, and adjusting the centering and verticality of a drill rod;
s5, drilling in soil layers, protecting walls and drilling in terrane multi-stage steps;
s6, monitoring the verticality of the drill rod by an internal and external double control method, and completing slag salvaging and hole cleaning at the bottom of a hole and hole forming acceptance inspection;
s7, manufacturing the reinforcement cage and installing an anti-floating structure according to the step 2, hoisting the reinforcement cage and installing an over-irrigation monitoring probe;
s8, placing a guide pipe, and cleaning holes for the second time by adopting a gas lift reverse circulation method;
s9, pouring underwater concrete and monitoring the super-pouring height, and pouring the underwater concrete to the super-pouring height;
s10, recovering the sensor probe and the signal wire.
2. The method for constructing the test pile for the ultra-buried depth in the rock formation according to claim 1, wherein the step S2 is carried out by drilling ahead, and a rock face BIM model is established as follows:
s201, aiming at a fluctuant rock surface, exploring one column and one pile by adopting five-hole advanced drilling; wherein, the distribution of five holes is that a center hole is arranged at the center of the pile, and the other four holes are distributed in a circle by taking the center hole as the center of the circle;
aiming at a common pile, carrying out one pile of porous exploration;
s202, building a pile foundation rock layer BIM model and an engineering geology BIM model according to exploration technical parameters, and drawing a single-pile rock face condition model;
and S203, determining the pile length according to the design requirements according to the elevation and the physical properties of the rock stratum.
3. The method for constructing the ultra-buried depth test pile in the rock formation according to claim 1, wherein the step S3 of positioning and burying the pile casing is as follows:
s301-1, measuring and placing a pile position by using a total station, and marking by using a mark pile; taking a pile position as a center, leading out four pile casing control points in four directions, leading the control points to be 1.0 time of the pile diameter from the center point of the pile position, and preparing a control pile;
s301-2, aligning the center of a drill bit to a pile core mark pile, excavating pile core soil, burying a pile casing according to a control pile, and enabling the distance between the outer wall of the pile casing and the four control piles to be equal to enable the center of the pile casing to be coincident with the center of a pile position.
4. The method for constructing the test pile with the ultra-deep burial depth in the rock formation according to claim 1, 2 or 3, wherein the manufacturing and the placing of the double sleeves of the test pile in the step S3 are specifically as follows:
s302-1, manufacturing a double sleeve: the inner sleeve and the outer sleeve are both threaded welded pipes made of 20mm steel plates and are made of Q345B; the outer sleeve has the diameter of (D +400) mm and the length of (H +300) mm and is used for resisting the soil body pressure; the inner sleeve is (D +200) mm in diameter and (H +300+1500) mm in length and serves as a concrete pouring template, and the two ends of the outer side of the inner sleeve, within the range of 2.5m, are wrapped with oil-immersed cotton felt and are fixed in an anti-sliding manner; wherein D represents the diameter of the test pile; h represents the depth of the foundation pit;
s302-2, placing of a double sleeve: drilling the outer sleeve to the elevation of the bottom of the foundation pit, and hoisting and fixing the outer sleeve; drilling a hole in the inner sleeve to penetrate into the pit bottom for 1m, and hoisting and fixing the inner sleeve; the construction process specifically comprises the following steps:
(1) drilling a pile hole with the diameter of (D +400) mm to the elevation of the bottom of the foundation pit;
(2) hoisting and fixing the outer sleeve;
(3) drilling a pile hole with the diameter of (D +200) mm to penetrate into the bottom of the foundation pit by 1.0 m;
(4) the inner sleeve wraps the oil-impregnated cotton felt;
(5) hoisting and placing a fixed inner sleeve;
(6) drilling a pile hole with the diameter of D to the bottom of the pile;
(7) and performing subsequent construction of the cast-in-place pile.
5. The method for constructing the test pile for the ultra-buried depth in the rock formation according to claim 1, wherein a drilling machine is in place in the step S4, and the centering and perpendicularity adjustment of a drill rod are as follows:
s401, before the drilling machine is in place, the site is required to be processed to be smooth and firm so as to meet the construction verticality requirement, and after the drilling machine is in place according to the specified position, the verticality of a mast and a drill rod is adjusted;
s402, when the hole positions are aligned, the hole positions are aligned by adopting a cross method;
s403, after the hole positions are aligned, starting a positioning system to perform positioning memory;
s404, after the hole is centered, the drilling machine cannot be shifted, and the angle of the drill arm cannot be changed randomly.
6. The method for constructing the test pile for the ultra-deep burial depth in the rock formation according to claim 1, wherein the soil layer drilling and the wall protection in the step S5 are as follows:
s501, before drilling, measuring the top elevation of the hole protecting cylinder by using a level gauge so as to control the drilling depth;
s502, when the drilling starts, paying attention to the drilling speed and adjusting the drilling speeds of different stratums;
s503, in the drilling process, keeping the mud surface not lower than the top of the protective cylinder by 400 mm;
s504, during drilling lifting, slurry is timely supplemented into the hole to keep the slurry surface not lower than the top of the protective cylinder by 400 mm;
s505, in the drilling process, observing and checking at any time by using an engineering detection ruler, and adjusting and controlling the verticality of the drill rod;
in the step S5, the rock stratum multi-stage step drilling is carried out according to the height of a drilling bucket, the vertical height of a step is 2m, the width of the step is 200mm, and the difference between the width of the step and the diameter is 400 mm.
7. The method for constructing the test pile for the ultra-buried depth in the rock formation according to claim 1, wherein the specific measures for monitoring the verticality of the drill rod by using an internal and external double control method in the step S6 are as follows:
s601, strictly controlling the verticality of the drill rod according to the standard, wherein the verticality of the drill rod is controlled according to 0.5%;
s602, reading the verticality of a drill rod in real time by an instrument panel in a cab of the rotary drilling rig, and carrying out internal control by an operator according to the reading of the instrument;
s603, adopting a theodolite by a manager to carry out external control in two directions; when the theodolite tracks and monitors to find out the verticality deviation, the 2mm guiding rule is adopted to accurately measure the verticality deviation, and the problem is found and adjusted in time.
8. The method for constructing the ultra-buried depth test pile in the rock stratum according to claim 1, wherein the manufacturing of the reinforcement cage and the installation of the anti-floating structure in the step S7 are specifically performed according to the step 2 as follows:
the bottom of steel reinforcement cage adds the anti structure of floating of welding, and anti structure of floating adopts the steel sheet to weld into the cross, and the cross welding is put at steel reinforcement cage bottom central point, and no language pipe mouth below 250mm department, the buoyancy of concrete to the steel reinforcement cage is resisted to the pressure that produces when the concrete pours.
9. The method for constructing the test pile for the ultra-deep burial depth in the rock formation according to claim 1 or 8, wherein the step S7 of hoisting the reinforcement cage and installing the ultra-irrigation monitoring probe comprises the following specific steps:
s701, placing a reinforcement cage into a pile hole by adopting a crawler crane, and installing a concrete over-irrigation monitoring probe at the upper end of the reinforcement cage when the upper end of the reinforcement cage is close to the hole opening, and fixing the reinforcement cage by using a special buckle;
s702, the probe is lowered along with the steel reinforcement cage and is connected with ground equipment through a data line, and the length of the data line is determined according to the depth of the pile hole;
s703, before concrete pouring, debugging equipment, and determining the upper limit of the concrete height, wherein the operation steps are as follows:
firstly, lowering the top end of a reinforcement cage to the height of an orifice;
secondly, mounting a monitoring probe and a data line;
connecting and debugging equipment;
fourthly, setting upper and lower limits of the designed elevation;
fifthly, pouring concrete;
sixthly, monitoring dynamic curve fluctuation through a mobile phone or a computer, and adjusting the supply amount of concrete according to the actual concrete pouring height;
seventhly, the curve is raised to the upper limit, namely the concrete is raised to the height exceeding the upper limit;
and (8) dismantling the recovery probe and the data line.
10. The method for constructing the test pile for the ultra-buried depth in the rock formation according to claim 1, wherein the underwater concrete pouring and the monitoring of the ultra-pouring height in the step S9 are as follows:
s901, before concrete is poured into a hopper, firstly, closing the hopper opening by using a plug until the hopper is full, and after the next car of concrete is in place, pulling the plug open by using a crane auxiliary hook;
s902, instantly pouring concrete into the pile bottom, enabling the slurry surface to rise and overflow the pile hole;
s903, starting a slurry pump, and delivering slurry to a slurry storage pool;
s904, placing the first concrete on the concrete surface all the time, and jacking from bottom to top; the remarks are as follows:
the whole pouring process ensures the control of the fluidity time of the first poured concrete, and the concrete cannot stay for 2 hours in a field; controlling the slump at 180-220 mm;
in the whole pouring process, the guide pipe is always kept 2-6m below the concrete surface, and a specially-assigned person should command and control the guide pipe when the guide pipe is lifted, so that the inclination and the displacement of the steel bar framework are avoided;
and thirdly, in the pouring process, monitoring the elevation of the concrete surface at any time by using a monitoring instrument, and strictly controlling the height of the over-poured concrete to be 800-1000mm, so as to ensure the effective pile length and the height of the pile head.
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Publication number Priority date Publication date Assignee Title
JP4354077B2 (en) * 2000-03-14 2009-10-28 株式会社竹中工務店 Pile loading test method and loading test apparatus
CN105350527A (en) * 2015-12-02 2016-02-24 广州市第二建筑工程有限公司 Prestressed pipe pile construction method based on building information modeling (BIM) and prestressed pipe pile
CN109183785A (en) * 2018-09-14 2019-01-11 鼎宸建设科技有限公司 A kind of Construction of Engineering Pile method based on BIM
CN110206024A (en) * 2019-05-07 2019-09-06 中建八局第二建设有限公司 A kind of method and structure for eliminating bored concrete pile side frictional resistance

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4354077B2 (en) * 2000-03-14 2009-10-28 株式会社竹中工務店 Pile loading test method and loading test apparatus
CN105350527A (en) * 2015-12-02 2016-02-24 广州市第二建筑工程有限公司 Prestressed pipe pile construction method based on building information modeling (BIM) and prestressed pipe pile
CN109183785A (en) * 2018-09-14 2019-01-11 鼎宸建设科技有限公司 A kind of Construction of Engineering Pile method based on BIM
CN110206024A (en) * 2019-05-07 2019-09-06 中建八局第二建设有限公司 A kind of method and structure for eliminating bored concrete pile side frictional resistance

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