CN113981958A - Method for plugging karst cave of mechanical pore-forming cast-in-place pile - Google Patents
Method for plugging karst cave of mechanical pore-forming cast-in-place pile Download PDFInfo
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- CN113981958A CN113981958A CN202111423406.7A CN202111423406A CN113981958A CN 113981958 A CN113981958 A CN 113981958A CN 202111423406 A CN202111423406 A CN 202111423406A CN 113981958 A CN113981958 A CN 113981958A
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000005553 drilling Methods 0.000 claims abstract description 100
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 60
- 239000010959 steel Substances 0.000 claims abstract description 60
- 230000002787 reinforcement Effects 0.000 claims abstract description 53
- 238000004140 cleaning Methods 0.000 claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 claims abstract description 17
- 239000013049 sediment Substances 0.000 claims description 33
- 239000002002 slurry Substances 0.000 claims description 33
- 238000013461 design Methods 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000005259 measurement Methods 0.000 claims description 15
- 239000002893 slag Substances 0.000 claims description 12
- 210000003205 muscle Anatomy 0.000 claims description 11
- 238000003466 welding Methods 0.000 claims description 10
- 238000007789 sealing Methods 0.000 claims description 9
- 238000007689 inspection Methods 0.000 claims description 8
- 238000003860 storage Methods 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 7
- 239000011435 rock Substances 0.000 claims description 6
- 230000005484 gravity Effects 0.000 claims description 5
- 238000011065 in-situ storage Methods 0.000 claims description 5
- 239000004576 sand Substances 0.000 claims description 5
- 238000004062 sedimentation Methods 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- 229910000278 bentonite Inorganic materials 0.000 claims description 3
- 239000000440 bentonite Substances 0.000 claims description 3
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 3
- 230000000903 blocking effect Effects 0.000 claims description 3
- 239000004927 clay Substances 0.000 claims description 3
- 238000010586 diagram Methods 0.000 claims description 3
- 238000009826 distribution Methods 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 239000011241 protective layer Substances 0.000 claims description 3
- 230000002441 reversible effect Effects 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 238000009736 wetting Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 7
- 239000002689 soil Substances 0.000 abstract description 5
- 239000010410 layer Substances 0.000 description 6
- 230000001681 protective effect Effects 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 241000755266 Kathetostoma giganteum Species 0.000 description 2
- 210000000481 breast Anatomy 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
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Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
Abstract
The invention relates to a method for plugging a karst cave of a mechanical pore-forming cast-in-place pile, which belongs to the technical field of karst cave filling and comprises the following steps: s1, measuring and lofting; s2, manufacturing and embedding the steel casing; s3, positioning a drilling machine; s4, drilling a hole by a drilling machine; s5, positioning the karst cave; s6, drilling a final hole by a drilling machine; s7, clearing holes and checking; s8, manufacturing and installing a reinforcement cage; s9, descending a conduit; s10, secondary hole cleaning; and S11, pouring concrete underwater. The method solves the problem that the concrete over-filling amount is difficult to control because the size of the karst cave cannot be judged in the pile foundation, has simple, convenient and efficient construction, reduces the construction period compared with the traditional backfilled soil for re-drilling, reduces the cost compared with the method of directly pouring concrete to fill the karst cave, reduces the pollution to the environment, has better social benefit and economic benefit, and is worthy of popularization and use in similar projects in the future.
Description
Technical Field
The invention relates to the technical field of karst cave filling, in particular to a karst cave plugging method for a mechanical hole-forming cast-in-place pile.
Background
The method is characterized in that a small karst cave can be integrally dug out, and a large karst cave at the bottom of the hole is backfilled by stone filling concrete to form a hole so as to be changed into a side wall karst cave.
Aiming at the problem that the side wall has the karst cave, the position and the size of the karst cave are judged according to measurement and field measurement, and the karst cave in a shallow layer within 4m can be solved by adopting a steel casing or large excavation. The karst cave with the depth exceeding 4m can be plugged by wrapping the quick and easy closing net outside the side wall reinforcement cage of the karst cave under the condition that the size of the karst cave can not be judged, so that a large amount of waste caused by filling the karst cave with concrete is reduced.
Disclosure of Invention
The invention aims to provide a method for plugging a karst cave of a mechanical cast-in-situ bored pile, which aims to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for plugging a karst cave of a mechanical cast-in-situ bored pile comprises the following steps:
s1, measurement lofting: determining the position of a pile hole, pulling a cross wire nail according to a pile positioning point to put four control guard piles, and controlling the embedding position of the pile casing and the accurate positioning of a drilling machine by taking the four control guard piles as a reference;
s2, manufacturing and embedding the steel casing: the steel casing is formed by rolling a steel plate, the inner diameter of the steel casing is larger than the outer diameter of the control pile, and stiffening rings are welded around the two ends of the steel casing;
s3, positioning a drilling machine: the position of the drilling machine is accurately determined through the measured control fender pile, the stability of the drilling machine is ensured, and the drill rod is adjusted to keep a vertical state;
s4, drilling a hole by a drilling machine: firstly, preparing slurry, and then drilling;
s5, positioning the karst cave: the method comprises the steps of performing preliminary positioning according to the karst cave position displayed by a measurement report in combination with the drilling depth, blocking the ground slurry from flowing into a hole, rapidly descending the slurry surface in the hole when the karst cave is drilled to a specific position, enabling the hole depth position to be approximate to the top elevation of the karst cave on the side wall, calculating the minimum capacity of the karst cave according to the descending height of the slurry surface, and determining the approximate bottom elevation of the karst cave according to the bottom elevation of the karst cave displayed by the measurement report in combination with a drilled rock sample, thereby approximately determining the section size of the karst cave on the side wall of the hole;
s6, drilling a final hole by a drilling machine: after the drilling hole reaches the design depth, verifying the geological condition, reporting to a supervision engineer for acceptance after confirming that the design and standard inspection requirements are met, and immediately cleaning the hole after the acceptance of the supervision engineer is qualified;
s7, clearing holes and checking;
s8, manufacturing and installing a reinforcement cage: manufacturing a reinforcement cage according to a reinforcement distribution diagram, manufacturing the reinforcement cage in two sections according to the depth of a pile hole, wherein the first section is a fixed-length reinforcement cage (combined with the hoisting height of a crane), the second section is manufactured according to the actual depth of the pile hole, the manufacturing length of the reinforcement cage is determined according to the actual depth of the pile hole, the reinforcement cage which is manufactured in sections and qualified in acceptance is transported to a pile hole opening to be hoisted and placed into the pile hole, and the two sections of reinforcement cages are welded by adopting one-side welding when being connected, wherein the welding length is 10 d;
s9, a lower conduit: measuring the actual length of the guide pipe section by section during the installation of the guide pipe, numbering the actual length of the guide pipe section by section, and recording the actual length of the guide pipe so as to control the depth of the buried pipe in the concrete pouring process;
s10, secondary hole cleaning;
s11, underwater concrete pouring: the quantity of the poured concrete can meet the requirements that the depth of the conduit embedded for the first time is not less than 1m and the height of the bottom of the filled conduit is required, the depth of the conduit embedded into the concrete during bottom sealing is not less than 1m, the volume of the first batch of concrete is determined according to the diameter of the pile, the depth of the conduit embedded and the volume of the concrete in the conduit, the mixed concrete is transported to a pile foundation port by a concrete transport vehicle and is injected into a hopper lifted by a drilling machine, the volume of the concrete in the vehicle is about 8m3, the volume is uniformly commanded by one person, after both sides are prepared, a water-proof bolt and a valve are simultaneously opened for bottom sealing, the isolation bolt is a steel plate, the steel plate is pulled by a thin steel wire rope and is lifted by a tower crane or an automobile crane.
As a further technical solution of the present invention, in S1, a total station is used to determine the position of the pile hole.
As a further technical scheme of the invention, the thickness of the steel plate in the S2 is 6mm, the inner diameter of the steel casing is 0.2-0.4m larger than the outer diameter of the control pile, and the steel casing is 0.3m higher than the ground.
As a further technical solution of the present invention, the drilling rig in S3 is a rotary drilling rig.
As a further technical solution of the present invention, the slurry in S4 is prepared by: setting a mud pit containing a sedimentation tank for returning mud and a mud storage tank on site, wherein the volume of the mud pit is 1.5-2.0 times of the volume of a drilled hole, sealing the bottom and the periphery of the mud pit to prevent mud from flowing outwards, and using clay powder for making mud or bentonite for making mud;
the drilling holes in the S4 are as follows: the drilling bucket is used for self weight and pressurization as drilling power, the short strip-shaped column is advanced once to display the current drilling depth of the drill bit, the strip-shaped column dynamically displays the moving position of the drill bit, the number of the hole depth displays the total depth of the hole, after the drilling bucket is extruded and filled with drilling slag, the drilling bucket is lifted out of the ground, a rotary operating handle is operated to enable the machine to rotate to the position in the direction of an earthwork transport vehicle, the drilling slag is loaded into the earthwork vehicle by a loader and is transported to a proper place for processing of abandoning the earthwork; and the water level in the hole is ensured to be consistent with the water level outside the steel casing in the drilling process.
As a further technical solution of the present invention, the core solid situation in S6 is obtained by drilling slag, comparing the drilling slag with a geological histogram, and comparing the drilling slag with a rock sample of a first pile acceptance seal sample to verify whether the geological situation meets design requirements, if the geological situation does not meet survey design data, notifying a supervision engineer and a field design representative to confirm, if the geological situation meets the design requirements, immediately checking the hole depth, the hole diameter and the hole pattern, detecting the hole diameter, the hole wall, the verticality and other detection items by using a hole detector, detecting the hole depth and the sediment thickness as a formed hole, measuring the hole depth L2 by using a measuring rope according to the drilling depth L1 of a rotary drilling display interface, comparing the hole depth L1 with the hole depth L2, and if the L2 is less than L1, replacing a bottom clearing drill bit, clearing the bottom, and re-measuring the hole depth.
As a further technical solution of the present invention, when the emptying acceptance in S7 is performed, the wet hole cleaning is performed by using a slurry changing method, the water level in the hole is maintained during the hole cleaning, the dry hole sediments can be cleaned by using a flat head drill after the precipitation, and the front hole cleaning must meet the following standards: the mud discharged or extracted from the holes has no granular feeling, the specific gravity of the mud is no more than 1.03, the sand content is less than 2 percent, and the viscosity is 17-20 s; before pouring the underwater concrete, the thickness of the sediment at the bottom of the hole is not more than 5cm, and the measurement of the sediment at the bottom of the hole is as follows: the hole depth is measured around the hole wall by adopting a measuring rope with a front-end suspended flat weight, the number of measuring points is not less than 4, the difference between the bottom elevations of the measuring rope and the measuring point is the sediment thickness, a steel ruler is required to be adopted to check the measuring rope before each measurement, and the hole cleaning operation is strictly forbidden to be replaced by a method of deepening the drilling depth.
As a further technical solution of the present invention, in S8, it is to be ensured that the positions, the intervals, and the number of the reinforcing bars meet the specification and the specification requirements of the drawing; the welding of main muscle staggers each other, the joint number in the 35d within range must not exceed the half of reinforcing bar total number, steel reinforcement cage's hoisting point is provided with stiffening rib or spiral stirrup, stiffening rib and main muscle are connected and are adopted spot welding, spiral stirrup and main muscle are connected and adopt the ligature, for guaranteeing steel reinforcement cage's protective layer thickness, it supports to weld U type muscle in advance outside steel reinforcement cage, the interval along the stake length is 2m, 4 departments are no less than to horizontal circumference, it supports to weld one U type muscle at solution cavity section interval 20cm, adopt the bundle silk along steel reinforcement cage a week ligature net that easily closes up soon, each 0.5m of solution cavity scope is grown out from top to bottom, go up the outside folding 2cm angle 45 of end.
According to a further technical scheme, after the guide pipe in the S10 is put in place, hole bottom sediment detection is immediately carried out, when the sediment thickness does not meet design requirements, gas lift reverse circulation secondary hole cleaning is adopted, during circulation, a mud water head is kept, high-quality mud is supplemented to prevent collapse, after hole cleaning is finished and is qualified through field inspection of a supervision engineer, a mud suction elbow is immediately detached, underwater concrete is poured, the thickness of the sediment at the hole bottom before the concrete is poured is not more than 5cm, sediment in the hole is measured through a front-end hanging weight measuring rope, and the measured difference is the sediment thickness.
As a further technical solution of the present invention, before pouring concrete in S11, a concrete conveying pipeline and a container need to be sprinkled with water for wetting, then a water-proof facility is installed in the filling pipe, and after the storage hopper is filled with concrete, underwater concrete is poured.
Compared with the prior art, the invention has the beneficial effects that: the problem that the concrete over-irrigation amount is difficult to control due to the fact that the size of the karst cave cannot be judged in the pile foundation is solved; the construction is simple and efficient, the construction period is shortened compared with the traditional backfilled soil by re-drilling, the cost is reduced compared with the method of directly pouring concrete to fill the karst cave, the pollution to the environment is reduced, and the method has good social benefit and economic benefit and is worth of being popularized and used in similar projects in future.
Drawings
FIG. 1 is a cross-sectional view of the present invention prior to the location of a cavern;
FIG. 2 is a cross-sectional view of the present invention in the positioning of a cavern;
FIG. 3 is a cross-sectional view of the present invention after the cavern has been positioned;
FIG. 4 is a cross-sectional view of the reinforcement cage of the present invention as installed;
FIG. 5 is a cross-sectional view of a quick and easy heal web of the present invention;
FIG. 6 is a cross-sectional view of a downcomer according to the present invention;
FIG. 7 is a cross-sectional view of the present invention prior to placement of the underwater concrete;
FIG. 8 is a cross-sectional view of the present invention after underwater concrete placement;
FIG. 9 is a process flow diagram of the present invention.
In the figure: 1-slurry, 2-drilling machine, 3-steel casing, 4-karst cave, 5-reinforcement cage, 6-fast and easy closing net, 7-conduit, 8-funnel and 9-concrete.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
The embodiment of the invention is realized in such a way that the method for plugging the karst cave of the mechanical pore-forming cast-in-place pile shown in figures 1 to 8 comprises the following steps:
s1, measurement lofting:
and accurately positioning the position of the pile hole by adopting a total station, pulling a cross wire nail according to the pile positioning point, putting four control piles, and controlling the embedding position of the pile casing and the accurate positioning of the drilling machine 2 by taking the four control piles as references. The pile protection needs to be well protected to prevent disturbance in the construction process.
S2, manufacturing and embedding the steel casing 3:
the pile casing is formed by rolling a 6mm steel plate, the inner diameter of the pile casing is 0.2-0.4m larger than the designed pile diameter, and stiffening rings are welded on the peripheries of the upper opening and the lower opening.
The pile foundation steel pile casing 3 is a steel pile casing 3 with the length of 2 meters. When the pile casing is installed, an operator of the drilling machine 2 enlarges a pile hole by using a reamer, and then presses the steel pile casing 3 into a designed elevation by using a high-torque drill bit. Before and after the protective cylinder is pressed in, the vertical position of the protective cylinder is adjusted by an accurate level instrument leaning against the protective cylinder. The top of the casing is generally 0.3m higher than the original ground so as to facilitate the positioning of a drill bit and the protection of a pile hole.
S3, positioning the drilling machine 2:
the rotary drilling rig 2 is adopted in the project, and when the drilling rig 2 is in place, whether the performance state of the drilling rig 2 is good or not is checked in advance, so that the normal work of the drilling rig 2 is ensured.
The position of the drilling machine 2 is accurately determined through the measured pile position, the stability of the drilling machine 2 is guaranteed, and after the drilling rod is basically vertical through manual rough leveling, the drilling rod can be adjusted to be in a vertical state through an automatic control system.
S4, drilling a hole by a drilling machine 2:
1) preparation of slurry 1:
for a rock-soil layer with good cohesiveness, a dry or clean water drilling process is adopted, mud 1 for wall protection is not needed, and crushed stone and soil within the range of 0.5m of an orifice are required to be cleaned. For loose and easily collapsed stratum or underground water distribution and unstable hole wall, a static mud 1 wall protection drilling process is required.
A mud 1 pool (a sedimentation pool containing repulping and a mud 1 storage pool) is arranged on site, the volume of the mud 1 pool is generally 1.5-2.0 times of the volume of a drilled hole, and plastic cloth is laid at the bottom and the periphery of the mud 1 pool or other sealing measures are adopted to prevent the mud 1 from flowing out.
The equipment for preparing the slurry 1 has two types, namely a slurry 1 stirrer and a hydraulic stirrer. When clay powder is used for making slurry, a hydraulic stirrer is preferably used; when bentonite is used for making slurry, a slurry 1 stirrer is used.
All performance indexes should be tested after slurry making, the specific gravity and the sand content of the slurry 1 should be tested at any time in the drilling process, a test record table of the slurry 1 is filled, geological changes are noticed at any time, the performance indexes of the slurry 1 are adjusted at any time according to the changes of geological conditions, and all indexes of the slurry 1 are guaranteed to meet the standard requirements.
A recovered mud 1 pool is arranged on a drilling construction site and used as recovered breast wall mud 1, the mud 1 is transported to a mud storage pool after being precipitated and purified, and is further processed in the mud storage pool (a proper amount of soda and CMC are added to improve the performance of the mud 1) and is reused after being tested to be qualified.
2) Drilling operation:
when the hole is opened, the dead weight and the pressurization of the drilling bucket are used as drilling power, the short bar-shaped column is advanced once to display the current drilling depth of the drill bit, the movement position of the drill bit is dynamically displayed by the long bar-shaped column, and the total depth of the hole is displayed by the number of the hole depth. After the drill bucket is squeezed and filled with the drill slag, the drill bucket is lifted out of the ground, the rotary operating handle is operated to enable the machine to rotate to the position in the direction of the earthwork transport vehicle, the drill slag is loaded into the earthwork vehicle by a loader and is transported to a proper place for processing of abandoning the earthwork.
Controlling the footage speed according to geological conditions in the drilling process, wherein the drilling speed can be properly accelerated when the hard stratum is drilled into the soft stratum; when the soft stratum is changed into the hard stratum, slowing down and slowly advancing; in the stratum with easy diameter shrinkage, the hole sweeping times are properly increased to prevent the diameter shrinkage; drilling the hard plastic layer at a high rotating speed to improve the drilling efficiency; the sand layer adopts slow speed to drill slowly and increases the specific gravity and viscosity of the mud 1 properly.
Along with drilling, the slurry 1 continuously flows into the pile hole, and the water level in the hole is ensured to be consistent with the water level outside the casing.
S5, positioning karst cave 4:
and performing primary positioning according to the position of the measured karst cave 4 in combination with the drilling depth, and blocking the ground slurry 1 from flowing into the hole. When the concrete position of the karst cave 4 is drilled, the surface of the slurry 1 in the hole can rapidly descend, the depth position of the hole can approximate to the top elevation of the karst cave 4 on the side wall at the moment, and the minimum volume of the karst cave 4 can be measured according to the descending height of the surface of the slurry 1. And then, the approximate bottom elevation of the karst cave 4 is judged according to the measured and displayed bottom elevation of the karst cave 4 by combining the drill hole rock sample. Thereby approximately determining the cross-sectional dimension of the cavern 4 at the side wall of the hole.
S6, drilling the final hole by the drilling machine 2:
after the borehole reaches the design depth, the geology must be verified. And (4) comparing the drilling slag with the rock sample of the first pile acceptance seal sample in comparison with the geological histogram so as to verify whether the geological condition meets the design requirement. If the survey design data is not matched, the supervision engineer and the site design representative are informed to perform the confirmation process in time. If the design requirements are met, the hole depth, the hole diameter and the hole pattern are immediately checked.
And detecting the detection items such as the aperture, the hole wall, the verticality and the like by using a hole detector.
Detecting the hole depth and the thickness of sediments: after hole forming, according to the drilling depth L1 of the display interface of the rotary drilling rig, the hole depth L2 is measured by using a measuring rope, the hole depth L2 is compared with the hole depth L2, if the hole depth L1 is smaller than the hole depth L1, a bottom cleaning drill bit is replaced, bottom cleaning is carried out, and the hole depth is measured again.
And after the requirements of design and inspection are met, the supervision engineer is requested to check, and the hole is immediately cleaned after the supervision engineer checks to be qualified.
S7, cleaning and checking:
and cleaning the wet holes by adopting a slurry changing method, and keeping the water level in the holes during cleaning. The dry-hole sediment can be cleaned by a flat-head drill after sedimentation.
The purpose of hole cleaning is to clean drilling slag and a sediment layer, reduce the sediment thickness of the hole bottom as much as possible and prevent the pile bottom from retaining excessive thick sediment to reduce the bearing capacity of the pile. And cleaning the holes twice, wherein the first hole cleaning is performed after the drilling depth reaches the design depth, and the first hole cleaning needs to meet the specification requirement, otherwise, the steel reinforcement cage 5 is not required to be placed.
And (3) after the steel reinforcement cage 5 is installed in place, lowering the guide pipe 7 and then cleaning the hole for the second time, wherein the hole cleaning before pouring the concrete 9 must meet the following standard:
the slurry 1 discharged or drawn from the hole has no granular feeling, the specific gravity of the slurry 1 is no more than 1.03, the sand content is less than 2 percent, and the viscosity is 17-20 s; the thickness of the sediment at the bottom of the hole before the underwater concrete 9 is poured is not more than 5 cm. Measuring the sediment at the bottom of the hole: the hole depth is measured around the hole wall by adopting a measuring rope with a front-end suspended flat weight, the number of measuring points is not less than 4, the difference between the bottom elevations of the measuring rope and the measuring point is the sediment thickness, a steel ruler is required to be adopted to check the measuring rope before each measurement, and the hole cleaning operation is strictly forbidden to be replaced by a method of deepening the drilling depth.
S8, manufacturing and installing the reinforcement cage 5:
and manufacturing the reinforcement cage 5 according to the reinforcement map, and manufacturing the reinforcement cage in two sections according to the depth of the pile hole, wherein the first section is the fixed-length reinforcement cage 5 (combined with the lifting height of a crane), and the second section is manufactured by determining the actual depth of the pile. Ensuring that the position, the interval and the number of the steel bars meet the requirements of the specification and the specification of a drawing; the main bars are welded in a staggered mode, and the number of joints within the range of 35d is not more than half of the total number of the steel bars.
The joint of the spiral stirrup or the stiffening rib of the reinforcement cage 5 is welded, the stiffening rib is connected with the main rib by spot welding, and the spiral stirrup is connected with the main rib by binding.
In order to prevent the reinforcement cage 5 from deforming during transportation and hoisting, the hoisting point position must be reinforced, and reinforcing ribs are encrypted if necessary.
For guaranteeing the protective layer thickness of steel reinforcement cage 5, weld U type muscle in advance in the steel reinforcement cage 5 outside and support, be 2m along the long interval of stake, 4 departments are no less than to horizontal circumference. A U-shaped rib support is welded at the interval of 20cm between the 4 sections of the karst cave, binding quick and easy closing nets 6 are bound along the circumference of a reinforcement cage 5 by binding wires, the upper and lower parts of the U-shaped rib support are 0.5m longer than the range of 4 parts of the karst cave, and the upper and lower openings of the U-shaped rib support are folded outwards by an angle of 45 degrees.
And (3) carrying out sectional manufacturing on the processing site, and transporting the qualified reinforcement cage 5 to an orifice to be hung in a hole, wherein the length of the two sections of reinforcement cages 5 is 10d by adopting one-side welding when being connected. When the steel reinforcement cage is transported and hoisted, deformation is prevented, the steel reinforcement cage is placed to be aligned with a hole position, collision on the hole wall is avoided, and the steel reinforcement cage 5 is fixed immediately after the top of the steel reinforcement cage 5 reaches a designed elevation so as to prevent the steel reinforcement cage 5 from floating upwards when concrete 9 is poured. And after the whole reinforcement cage 5 is manufactured, the whole reinforcement cage is qualified through self-inspection and then is reported to a supervision engineer for inspection and approval, and then the whole reinforcement cage is transported to a construction site in a segmented manner by using a tower crane in a reinforcement machining site. Before the installation of the steel reinforcement cage 5, adhered soil and oil stains are removed, and the steel reinforcement is ensured to be tightly bonded with the concrete 9.
S9, downcomer 7:
when the qualified guide pipe 7 is installed, the actual length of the guide pipe 7 is measured section by section, and the guide pipe 7 is numbered in sequence, and the record is made so as to control the pipe burying depth in the pouring process of the concrete 9. And whether the rubber ring is arranged or not and whether the threads at the two ends of each conduit 7 are buckled or not are checked, and the like, so that the phenomena of water inflow and the like of the conduits 7 in the filling process are avoided.
S10, secondary hole cleaning:
after the guide pipe 7 is put in place, the sediment detection at the bottom of the hole is immediately carried out, if the sediment thickness does not meet the design requirement, the hole is cleaned twice by adopting gas lift reverse circulation, and the water head of the slurry 1 is kept and the high-quality slurry 1 is supplemented during circulation to prevent collapse. After the hole cleaning is finished and the hole cleaning is qualified through the field inspection of a supervision engineer, the mud suction elbow is immediately dismantled, and the underwater concrete 9 is poured.
The thickness of the sediment at the bottom of the hole before the concrete 9 is poured is not more than 5cm, the sediment in the hole is measured by adopting a measuring rope with a front-end suspended flat weight, and the measured difference value is the sediment thickness.
S11, pouring underwater concrete 9:
before pouring the concrete 9, a conveying pipeline and a container of the concrete 9 need to be sprayed with water for wetting, then a water-resisting facility is installed in the filling guide pipe 7, and after the storage hopper is filled with the concrete 9, the underwater concrete 9 begins to be poured. The quantity of the first pouring concrete 9 can meet the requirements that the first embedding depth of the guide pipe 7 is not less than 1m and the bottom height of the filling guide pipe 7 is required, the embedding depth of the guide pipe 7 in the concrete 9 is not less than 1m during bottom sealing, the amount of the first pouring concrete 9 is determined according to the pile diameter, the embedding depth of the guide pipe 7 and the amount of the concrete 9 in the guide pipe 7, and the mixed concrete 9 is transported to a pile foundation port by a concrete 9 transport vehicleThe concrete is injected into a hopper lifted by the drilling machine 2, and the volume of the concrete 9 in the vehicle is about 8m3And one person uniformly commands the water-proof bolt and the valve to be opened simultaneously for bottom sealing after both the two parties are prepared, the water-proof bolt adopts a steel plate, and the steel plate is dragged by a thin steel wire rope and lifted by a tower crane or a truck crane.
After the first batch of concrete 9 falls down, the concrete 9 should be continuously poured. During the perfusion process, the depth of the conduit 7 is preferably controlled to be 2-6 m.
Secondly, a measuring hammer with the weight not less than 4kg is adopted to measure the rising height of the surface of the concrete 9 in the hole frequently in the process of pouring the concrete 9, the guide pipe 7 is rapidly disassembled step by step after reaching a certain burial depth, and the height of the surface of the concrete 9 in the hole is detected once before the guide pipe 7 is lifted each time. The measuring rope for measurement is checked by a steel ruler before and after each pile is poured, so that errors are avoided.
Controlling the elevation of the poured pile top to be higher than the designed elevation by more than 0.3m so as to ensure the strength of the concrete 9, and chiseling off the redundant pile head to ensure that the pile head has no loose layer.
Fourthly, after the concrete 9 is poured, the guide pipe 7, the funnel 8 and the like are cleaned and checked in time to be used for the next hole.
Before pouring the underwater concrete 9, a relevant detection form for checking the conditions of the bored pile and the reinforcement cage 5 is filled, and a pouring record of the underwater concrete 9 is filled in the process of pouring the underwater concrete 9.
Please refer to fig. 9 for a flowchart of the above method.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. A method for plugging a karst cave of a mechanical cast-in-situ bored pile is characterized by comprising the following steps:
s1, measurement lofting: determining the position of a pile hole, pulling a cross wire nail according to a pile positioning point to put four control guard piles, and controlling the embedding position of the pile casing and the accurate positioning of a drilling machine by taking the four control guard piles as a reference;
s2, manufacturing and embedding the steel casing: the steel casing is formed by rolling a steel plate, the inner diameter of the steel casing is larger than the outer diameter of the control pile, and stiffening rings are welded around the two ends of the steel casing;
s3, positioning a drilling machine: the position of the drilling machine is accurately determined through the measured control fender pile, the stability of the drilling machine is ensured, and the drill rod is adjusted to keep a vertical state;
s4, drilling a hole by a drilling machine: firstly, preparing slurry, and then drilling;
s5, positioning the karst cave: the method comprises the steps of performing preliminary positioning according to the karst cave position displayed by a measurement report in combination with the drilling depth, blocking the ground slurry from flowing into a hole, rapidly descending the slurry surface in the hole when the karst cave is drilled to a specific position, enabling the hole depth position to be approximate to the top elevation of the karst cave on the side wall, calculating the minimum capacity of the karst cave according to the descending height of the slurry surface, and determining the approximate bottom elevation of the karst cave according to the bottom elevation of the karst cave displayed by the measurement report in combination with a drilled rock sample, thereby approximately determining the section size of the karst cave on the side wall of the hole;
s6, drilling a final hole by a drilling machine: after the drilling hole reaches the design depth, verifying the geological condition, reporting to a supervision engineer for acceptance after confirming that the design and standard inspection requirements are met, and immediately cleaning the hole after the acceptance of the supervision engineer is qualified;
s7, clearing holes and checking;
s8, manufacturing and installing a reinforcement cage: manufacturing a reinforcement cage according to a reinforcement distribution diagram, manufacturing the reinforcement cage in two sections according to the depth of a pile hole, wherein the first section is a fixed-length reinforcement cage (combined with the hoisting height of a crane), the second section is manufactured according to the actual depth of the pile hole, the manufacturing length of the reinforcement cage is determined according to the actual depth of the pile hole, the reinforcement cage which is manufactured in sections and qualified in acceptance is transported to a pile hole opening to be hoisted and placed into the pile hole, and the two sections of reinforcement cages are welded by adopting one-side welding when being connected, wherein the welding length is 10 d;
s9, a lower conduit: measuring the actual length of the guide pipe section by section during the installation of the guide pipe, numbering the actual length of the guide pipe section by section, and recording the actual length of the guide pipe so as to control the depth of the buried pipe in the concrete pouring process;
s10, secondary hole cleaning;
s11, underwater concrete pouring: the quantity of the poured concrete can meet the requirements that the first embedding depth of the guide pipe is not less than 1m and the bottom height of the filling guide pipe is required, the depth of the guide pipe embedded into the concrete during bottom sealing is not less than 1m, the volume of the first batch of concrete is determined according to the pile diameter, the embedding depth of the guide pipe and the volume of the concrete in the guide pipe, the mixed concrete is transported to a pile foundation opening by a concrete transport vehicle and is injected into a hopper lifted by a drilling machine, and the volume of the concrete in the vehicle is about 8m3And one person uniformly commands the water-proof bolt and the valve to be opened simultaneously for bottom sealing after both the two parties are prepared, the water-proof bolt adopts a steel plate, and the steel plate is dragged by a thin steel wire rope and lifted by a tower crane or a truck crane.
2. The method for plugging a karst cave of a mechanical bored pile according to claim 1, wherein a total station is used to determine the position of the pile hole in S1.
3. The method for plugging the karst cave of the mechanical bored pile according to claim 1, wherein the thickness of the steel plate in the step S2 is 6mm, the inner diameter of the steel casing is 0.2-0.4m larger than the outer diameter of the control pile, and the height of the steel casing is 0.3m higher than the ground.
4. The method for plugging the karst cave of the mechanical bored pile according to claim 1, wherein the drilling rig in the step S3 is a rotary drilling rig.
5. The method for plugging the karst cave of the mechanical pore-forming cast-in-place pile according to claim 1, wherein the slurry in S4 is prepared by the following steps: setting a mud pit containing a sedimentation tank for returning mud and a mud storage tank on site, wherein the volume of the mud pit is 1.5-2.0 times of the volume of a drilled hole, sealing the bottom and the periphery of the mud pit to prevent mud from flowing outwards, and using clay powder for making mud or bentonite for making mud;
the drilling holes in the S4 are as follows: the drilling bucket is used for self weight and pressurization as drilling power, the short strip-shaped column is advanced once to display the current drilling depth of the drill bit, the strip-shaped column dynamically displays the moving position of the drill bit, the number of the hole depth displays the total depth of the hole, after the drilling bucket is extruded and filled with drilling slag, the drilling bucket is lifted out of the ground, a rotary operating handle is operated to enable the machine to rotate to the position in the direction of an earthwork transport vehicle, the drilling slag is loaded into the earthwork vehicle by a loader and is transported to a proper place for processing of abandoning the earthwork; and the water level in the hole is ensured to be consistent with the water level outside the steel casing in the drilling process.
6. The method for plugging the karst cave of the mechanical pore-forming cast-in-place pile according to claim 1, wherein the core solid situation in S6 is that whether the geological situation meets the design requirements is verified by drilling slag and comparing with a geological histogram in combination with a rock sample of a first pile acceptance seal sample, if the geological situation does not meet the survey design data, a supervision engineer and a field design representative are timely notified to confirm and process, if the design requirements are met, the hole depth, the hole diameter and the hole pattern are immediately checked, detection items such as the hole diameter, the hole wall and the verticality are detected by a hole detector, after the hole depth and the sediment thickness are detected to be formed, the hole depth L2 is measured by a measuring rope according to the drilling depth L1 of a rotary drilling display interface, the hole depth L1 is compared with the hole wall and the hole depth is measured again by replacing a bottom-cleaning drill bit if the L2 is smaller than the L1.
7. The method for plugging a karst cave of a mechanical cast-in-situ pile according to claim 1, wherein in the emptying acceptance in the step S7, the hole is cleared by a slurry changing method in a wet hole clearing mode, the water level in the hole is kept in the hole clearing mode, the dry hole sediment can be cleared by a flat head drill after sedimentation, and the front hole clearing must meet the following standard: the mud discharged or extracted from the holes has no granular feeling, the specific gravity of the mud is no more than 1.03, the sand content is less than 2 percent, and the viscosity is 17-20 s; before pouring the underwater concrete, the thickness of the sediment at the bottom of the hole is not more than 5cm, and the measurement of the sediment at the bottom of the hole is as follows: the hole depth is measured around the hole wall by adopting a measuring rope with a front-end suspended flat weight, the number of measuring points is not less than 4, the difference between the bottom elevations of the measuring rope and the measuring point is the sediment thickness, a steel ruler is required to be adopted to check the measuring rope before each measurement, and the hole cleaning operation is strictly forbidden to be replaced by a method of deepening the drilling depth.
8. The method for plugging the karst cave of the mechanical cast-in-situ bored pile according to claim 1, wherein in the step S8, the positions, the intervals and the number of the reinforcing steel bars are ensured to meet the requirements of the specification and the specification of the drawing; the welding of main muscle staggers each other, the joint number in the 35d within range must not exceed the half of reinforcing bar total number, steel reinforcement cage's hoisting point is provided with stiffening rib or spiral stirrup, stiffening rib and main muscle are connected and are adopted spot welding, spiral stirrup and main muscle are connected and adopt the ligature, for guaranteeing steel reinforcement cage's protective layer thickness, it supports to weld U type muscle in advance outside steel reinforcement cage, the interval along the stake length is 2m, 4 departments are no less than to horizontal circumference, it supports to weld one U type muscle at solution cavity section interval 20cm, adopt the bundle silk along steel reinforcement cage a week ligature net that easily closes up soon, each 0.5m of solution cavity scope is grown out from top to bottom, go up the outside folding 2cm angle 45 of end.
9. The method for plugging the karst cave of the mechanical pore-forming cast-in-place pile according to claim 1, wherein after the guide pipe in S10 is put down in place, hole bottom sediment detection is immediately carried out, when the sediment thickness does not meet design requirements, gas lift reverse circulation secondary hole cleaning is adopted, during circulation, a mud water head is kept, high-quality mud is supplemented, collapse is prevented, after hole cleaning is finished and is qualified through field inspection of a supervision engineer, a mud suction elbow is immediately detached, underwater concrete is poured, the thickness of the hole bottom sediment before the concrete is poured is not more than 5cm, the sediment in the hole is measured by a front-end hanging flat weight measuring rope, and the measured difference value is the sediment thickness.
10. The method for plugging the karst cave of the mechanical pore-forming cast-in-place pile according to claim 1, wherein before the concrete is poured in the step S11, a concrete conveying pipeline and a container need to be sprayed with water for wetting, then a water-resisting facility is installed in the filling guide pipe, and after the storage hopper is filled with the concrete, the underwater concrete is poured.
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