CN110055957A - A kind of strong development ultra-fine hole pile construction method in karst region - Google Patents

Abstract

The present invention provides a kind of strong development ultra-fine hole pile construction method in karst region, by to hydrological geological conditions, duration, the combined factors such as existing machinery equipment consider, using a full set of pipe construction karst treatment cast-in-situ bored pile of 360 degree of revolutions, and form matched construction technology, the method is formed using summary by the project success, to overcome at present during bored pile construction, cause to lead to engineering accident due to collapse hole because failing to take effective measures, so that engineering cost greatly increases, duration seriously lags, even it is forced to interrupt construction, the punching method construction that Karst Geological Landscape cast-in-situ bored pile uses under normal circumstances, slabstone is backfilled in the engineering of punching, the measures such as concrete, construction speed is slow, and because backfill quantity is uncontrollable, construction period, cost is uncontrollable.Belong to building engineering construction field.

Description

A kind of strong development ultra-fine hole pile construction method in karst region

Technical field

The present invention relates to a kind of strong development ultra-fine hole pile construction methods in karst region, belong to building engineering construction field.

Background technique

Karst Geological Landscape is widely distributed in China, causes during bored pile construction because failing to take effective measures Collapse hole and lead to engineering accident so that engineering cost greatly increases, the duration is seriously lagged, in addition be forced interrupt construction.Rock The punching method construction that molten geotechnical boring bored concrete pile uses under normal circumstances, backfills slabstone, concrete etc. in the engineering of punching and arranges It applies, construction speed is slow, and because backfill quantity is uncontrollable, construction period, cost are uncontrollable.

Summary of the invention

China Railway Erju 1st Engineering Co., Ltd. is in construction No. 6 line first stage of the project SG6-3 bid section phoenix parks of Hangzhou Subway It stands in karst treatment cast-in-situ bored pile, by considering combined factors such as hydrological geological conditions, duration, existing machinery equipment, adopts With a full set of pipe construction karst treatment cast-in-situ bored piles of 360 degree of revolutions, and matched construction technology is formed, is answered by the project success The method is formed with summary, to overcome the above problem.

To solve the above problems, such a strong ultra-fine hole pile construction method in development karst region of proposed adoption, including it is as follows Step:

It surveys fixed pile center and positions, according to design drawing coordinate dimension, measure pile center, do and remember in the stake position of measurement Number, circular lines to be drawn as center and according to pile diameter, jacketing machine positioning plate is lifted to stake site, error is less than ± 10mm, described sleeve pipe machine is 360 degree of full circle swinging drill machine with casing, then host is hung to positioning plate, levels host, and lifting is put into The first segment steel sleeve of steel sleeve rotates a circle in host and gripping sleeve level machine and observes bottom tooth outer ring and aforementioned circle Astragal is overlapped；

The steel bushing tubular pole circumgyration incision soil body sinks to drilling, steel sleeve is clamped after steel sleeve machine is put into host, to cover tube bottom Casing external wall of upper portion verticality is observed within the allowable range on the basis of outer wall, after adjustment is vertical, base area Quality Control system cuts progress, Certain depth is drowned into steel sleeve and grabs soil casing out when sinking to syzygies grab bucket with crawler crane, until design predetermined depth；

The docking of steel bushing tubular pole, the soil that cleaning has been pressed on pipe nozzle before docking, lifting steel sleeve utilize above nozzle Nozzle interfacing part alignment on upper section pipe shaft outer wall, checks pipe verticality, controls in the range of 1/500, two people are opposite simultaneously Spot welding is fixed, and securely rear two people carry out layering in opposite directions simultaneously and are fully welded operation；Then, the interfacing part and suspension centre outside pipe shaft are removed；

Fabrication of reinforcing cage and lifting, steel reinforcement cage are made by design drawing and code requirement；When lifting, upper and lower two sections steel Muscle cage is docked in aperture, and human assistance is directed at hole location when lower cage, keeps the vertical of steel reinforcement cage；Steel reinforcement cage topmost sets position Muscle calculates the length of positioning bar, and positioning is welded after confirmation；When the concrete being perfused starts initial set, it is vertical to cut off locating framework Muscle；

Filling concrete；

Drilling machine displacement removes the tool pipe on ground after by steel sleeve drilling indentation to projected depth, i.e. machine is held tightly Part and epimerite tube top end position, then hang out tool pipe and drilling machine are moved to next hole location；

Pile quality detection.

In aforementioned construction method, when drilling, according to the soil property situation that drill hole geologic sectional view and scene are taken out, by different soil Layer controls rate of penetration and takes native depth, shows data according to rig operations disk gauge pressure, torsion is reached maximum but can not be crept into Steel bushing tubular pole is pushed, when cannot continue to take soil again in pipe, continuous supplementation water maintains there should be head in casing into hole, prevents pipe Outer soil, sand are gushed into pipe causes settlement of foundation accident to occur；When drilling, running check gauge pressure controls footage per bit, hard So that drill bit is freely up and down rotated when creeping on rock, often measures hole depth and forbid super grab；Reach 3 days to adjacent stake concrete and spuds in again； Must be steady when sinking to casing, avoid drill bit alloy from hitting.

In aforementioned construction method, the framework of steel reinforcement made is placed on smooth, dry place, when storage, each reinforcing rib The contour lumps of wood is all padded with ground contact position；Steel reinforcement cage is transferred using crane, temporarily adds rod before lifting in steel reinforcement cage, adds Its strong rigidity, upper and lower two sections steel reinforcement cage are docked in aperture, are directed at hole location by human assistance when lower cage, are kept hanging down for steel reinforcement cage Directly, it puts down gently, slow play, avoids collision hole wall；During hanging steel reinforcement cage, it is necessary to remain that reinforcing bar lorhumb line and stake axis are kissed It closes, and guarantees that stake top absolute altitude meets design requirement, steel reinforcement cage topmost sets positioning bar, positioning is calculated by the aperture absolute altitude measured The length of muscle crosschecks errorless rear welding positioning；When the concrete being perfused starts initial set, the vertical muscle of locating framework is cut off.

In aforementioned construction method, filling concrete, filling concrete depth is not less than 1.0m, pile concrete perfusion for the first time It being carried out in secondary pile hole cleaning half an hour after, and answers continuous pouring until pile, concrete face is higher than mouth 2.0m under conduit in filling process, Its lower end is embedded in depth no more than 6.0m before removing conduit every time；With the rising of hole inner concrete, needs quickly to remove section by section and lead Pipe, time are no more than 15min；In filling process, when conduit inner concrete is discontented, when containing air, subsequent concrete is answered Slowly funnel and conduit are poured into, the whole bucket of concrete must not be poured into pipe from top to down；Pile concrete, which need to surpass, pours 0.5~1m, After reaching intensity, design stake top absolute altitude above section is cut with pneumatic pick；

In aforementioned construction method, the detection of karst treatment cast-in-situ bored pile pile quality includes: that low strain dynamic method detection of pier foundation is complete Whole property, sound wave projective method detection of pier foundation integrality, autobalanced detection bearing capacity of pile foundation.

Technological principle are as follows: using 360 degree of full circle swinging drill machine with casing hydraulic gear and be aided with pressurization, carry out casing 360 degree of revolution cuttings, side indentation, to greatly reduce the frictional resistance between casing and soil layer, while it is continual to grab bucket Soil is taken, barrier and rock are grabbed out using punching when such as barrier and rock stratum, such drilling to completion, drilling, which meets, to be set Meter after code requirement, places steel reinforcement cage, pouring underwater concrete can pile, it is all that this method is particularly suitable for subway station Karst intense development area ultra-deep (thin) bored pile construction, " ultra-fine (depth) hole stake ": the cast-in-situ bored pile that design stake diameter is 1m, Drilling depth is up to 90 meters -100 meters, (embodying are as follows: stake diameter is small, and length is long, and the difficulty of construction relative to other pile foundations is larger).

This method not only convenient and quick construction, but also good economic benefit is created, concrete analysis situation is as follows:

It is analyzed from the construction time: for pile foundation construction in karst region, conventional impact drill construction method (single stake) construction Time is about 45 days, and this method only needs the completion that can construct for 5 days, saves the time 40 days, project pipe is made while shortening the construction period Expense cost is taken obviously to be saved；

Analyze from materials'use: karst region geological condition is generally divided into filling, half filling and empty three kinds of situations, It is constructed using conventional impact drill, needs to carry out impact holing again after first filling up solution cavity when encountering half filling and cavity, fill out It fills solution cavity filler and is generally rubble folder clay or the mixed rubble of clay, it is easy to collapse during impact holing, it is difficult to form shield Wall is also required in work progress not stop to backfill slabstone or concrete impacts to form retaining wall, and when encounter super large solution cavity, backfill Just amount is imponderable, and for this method using steel sleeve follow-up pore-forming, material requested cost is foreseeable.

Social benefit: 360 degree of full abrasion drill engineering method construction safeties, reliable in quality and convenient and efficient, at low cost, duration are used Short, benefit is good, and by taking the station of No. 6 line bid section phoenix parks first stage of the project SG6-3 of Hangzhou Subway as an example, which has 25 Stake, the duration is tight, construction task is arduous, karst treatment in station can be more safely and fast completed using the method, under guarantee One step station pit excavation is gone on smoothly, and construction period, the height by owner, designing unit, supervisor is praised.

Compared with prior art, the present invention has the further advantage that

1. pile quality is reliable, 360 degree of revolution full-sleeve pile foundation constructions are that pile driving construction is irrigated in steel sleeve, for Filling, half filling and empty geology in karst region, steel pile casting, can not be by geology shadow in karst region as pile foundation breast wall It rings, pile quality can be protected.

2. geological adaptability is strong, boulder, the sill that uniaxial compressive strength is 137~206MPa can be cut, be protected Card can smoothly enter into middle weathered rock formation after solution cavity.

3. drilling depth is deep, the cast-in-situ bored pile that design stake diameter is 1m, drilling depth is up to 90m.

4. verticality precision is high, verticality precision is up to 1/500.

5. construction efficiency is high, the more other construction methods of this method are limited small, the construction efficiency of bored concrete pile by environmental factor Height, risk are low.

Detailed description of the invention

Fig. 1 is construction technology process of the invention.

Specific embodiment

To make the object, technical solutions and advantages of the present invention clearer, the present invention is made into one below in conjunction with attached drawing The detailed description of step, it should be understood that described herein specific examples are only used to explain the present invention, is not used to limit this hair It is bright.

Embodiment

Referring to Fig.1, the present embodiment provides a kind of strong development ultra-fine hole pile construction methods in karst region.

One, preparation

1, design drawing should be carefully checked before constructing and scene is surveyed, and construction is planned according to arrangement of pile foundation figure in advance Sequentially.

It 2, is the bearing capacity for guaranteeing engineering pile under the bottom plate of station, engineering pile should all carry out Advance Drilling (one one under bottom plate Hole)；Advance drilling drilling depth is not less than 5 times of pile body design diameters below the absolute altitude of stake bottom；Such as set in 5 times of design pile bodies of stake bottom absolute altitude Solution cavity is encountered in meter diameter range, Ying Jixu is drilled down into, and pile body is kept to be located in 5 times of pile body design diameters in weathered rock formation.

3, after Advance Drilling (hole), every pile base depth need to be determined according to drilling data, to related Material, plant and labour propose plan of needs.

4, before construction is formally marched into the arena in levelling of the land, after carrying out site investigation, construction site ground obstacle, Bu Nengqing are removed That removes carries out safeguard measure, then flattens, tamps；Reasonable Arrangement construction machinery, transfer pipeline and power circuit position simultaneously, really Protect " three supplies and one leveling " of construction site.

Two, it surveys fixed pile center and positions

According to design drawing coordinate dimension, pile center is measured using total station, in the stake position steel nail or red paint of measurement It marks, draws the circular lines that a diameter is 1000 as center.Jacketing machine positioning plate is lifted to stake site, error is less than ± 10mm, then host is hung to positioning plate, horizontal device leveling host is carried using pile foundation.Lifting is put into steel sleeve first segment (coxopodite) steel sleeve rotates a circle in host and gripping sleeve level machine and observes bottom tooth outer ring and 1000 diameter circle of diameter Astragal is overlapped.Aperture notice is signed and issued after drilling machine is in place after quality inspection personnel passed examination.

Three, the steel bushing tubular pole circumgyration incision soil body sinks to drilling

1, clamp steel sleeve after steel sleeve machine is put into host, with messenger wire fall guiding ruler or two theodolites at 90 degree of orientation with Observation casing external wall of upper portion verticality, just can base area after adjustment is vertical in allowed band 1/500 on the basis of covering tube bottom outer wall Quality Control system cuts progress, is drowned into certain depth to steel sleeve and grabs soil casing out when sinking to syzygies grab bucket with crawler crane, directly To design predetermined depth.(punching crawl soil has certain impact force, as surrounding enviroment do not allow in combination with high platform rotary drilling rig Take soil).

2, when drilling, according to the soil property situation that drill hole geologic sectional view and scene are taken out, drilling speed is controlled by different soil Native depth to be spent and taken, data are shown according to rig operations disk gauge pressure, torsion is up to maximum but can not creep into pushing steel bushing tubular pole, When cannot continue to take soil again in pipe, into hole, continuous supplementation water (mud) maintains should have head in casing, prevents the outer soil of pipe, sand It is gushed into pipe and the accidents such as settlement of foundation is caused to occur.

3, creep into when, running check gauge pressure control footage per bit, on hard rock creep into when enable drill bit up and down from It is pre- preventing sticking by rotating.Often measurement hole depth forbids super grab.

4, to avoid influencing the solidification that adjacent hole has filled concrete, reach 3 days to adjacent stake (within the scope of 4D) concrete and spud in again, in order to avoid influence Concrete quality.

5, must be steady when sinking to casing, prevent drill bit alloy from hitting impaired.

Four, steel bushing tubular pole docks

1, caliber, Guan Shunzhi, end surfaces, groove, weld seam etc. is carried out to the steel bushing tubular pole marched into the arena to check.

2, the soil that cleaning has been pressed on pipe nozzle before docking lifts steel sleeve and utilizes upper section pipe shaft outer wall above nozzle Upper dedicated nozzle interfacing part alignment controls two people in the range of 1/500 with two theodolites at 90 degree of inspection pipe verticalities While opposite welding (spot welding) is fixed, secured rear two people carry out being layered simultaneously in opposite directions when going back is fully welded operation.

3, dedicated interfacing part and the suspension centre etc. outside pipe shaft are removed.

The design of pile foundation verticality, which is deteriorated, is not greater than 3/1000, therefore must first carry out an acceptance inspection when steel sleeve is marched into the arena, and protects The verticality of steel sleeve itself is demonstrate,proved, secondly, also having to code requirement operation when welding, guarantees welding quality.

Five, fabrication of reinforcing cage and lifting

1, steel reinforcement cage is processed

1) steel reinforcement cage is strictly controlled by design drawing and code requirement using live processing and fabricating, processing dimension.Steel For muscle cage main reinforcement using welding, weld length meets design requirement, and main reinforcement and stirrup use spot welding.Steel reinforcement cage is facilitated to be segmented for lifting It makes in advance, aperture field joint, splice is staggered by regulation.

It 2) is the protective layer thickness for guaranteeing bored concrete pile, using the method for reinforcing bar " ear ".Reinforcing bar " ear " is welded in skeleton master On the outside of muscle, 2~4m of spacing.To ensure steel reinforcement cage rigidity, lift by crane indeformable, it is desirable that add reinforcing rib every 2m.

3) framework of steel reinforcement made must necessarily be placed on smooth, dry place.When storage, each reinforcing rib and ground face contact The upper contour lumps of wood of place's all pads, in order to avoid it is stained with soil.Forming skeleton will be listed mark, error when avoiding lifting.

4) steel reinforcement cage completion of processing, submits a report asking for management examination, and qualified rear can be used.Fabrication of reinforcing cage tolerance is detailed in down Table:

1 pile foundation steel bar cage of table processes tolerance table

2, steel reinforcement cage is hung

1) steel reinforcement cage is transferred using crane.It is indeformable when in order to guarantee reinforcement cage hoisting, it is hung using two o'clock.In steel before lifting Temporarily add rod in muscle cage, reinforces its rigidity.Upper and lower two sections steel reinforcement cage is docked in aperture.

2) hole location is directed at by human assistance when cage under, keeps the vertical of steel reinforcement cage, is put down gently, slow play, avoids collision hole wall, sternly Prohibit Gao Timeng and puts and force tripping in.

3) during hanging steel reinforcement cage, it is necessary to remain that reinforcing bar lorhumb line and stake axis coincide, and guarantee stake top absolute altitude Meet design requirement.To prevent rising of steel cage during concrete pouring, steel reinforcement cage topmost sets positioning bar, is marked by the aperture measured Height calculates the length of positioning bar, crosscheck it is errorless after welding positioning.

4) when the concrete being perfused starts initial set, the vertical muscle of locating framework is cut off, making steel reinforcement cage not influences the contraction of concrete.It avoids The cohesive force of reinforced concrete is suffered a loss.

Steel reinforcement cage in the production process, have to guarantee verticality control, avoid because steel sleeve, drilling process and The deviation of steel reinforcement cage itself verticality causes steel reinforcement cage to fail to lay down.

Six, filling concrete

1, filling concrete depth is not less than 1.0m for the first time, pile concrete be poured in secondary pile hole cleaning half an hour after into Row, and answer continuous pouring until pile, concrete face should be higher than that mouth 2.0m under conduit in filling process, remove its lower end before conduit every time Depth is embedded in no more than 6.0m.

2, it with the rising of hole inner concrete, needs quickly to remove conduit section by section, the time is no more than 15min.

3, in filling process, when conduit inner concrete is discontented, when containing air, subsequent concrete, which should blow slowly, pours into leakage The whole bucket of concrete must not be poured into pipe from top to down, in order to avoid being formed in the tube high-pressure gasbag, squeeze out the rubber of tube coupling by bucket and conduit Glue gasket.

4, there are one layer of laitance needs to cut on concrete upper layer, and pile concrete, which need to surpass, thus pours 0.5~1m, reaches intensity Afterwards, design stake top absolute altitude above section is cut with pneumatic pick.

5, concreting record is carried out.

6, filling process, which will be protected, is installed in monitoring element on steel reinforcement cage.

7, the raw material of bored concrete pile and concrete strength have to comply with the regulation of design requirement and job specfication.And concrete Practical irrigation amount cannot be less than design value.

Seven, drilling machine shifts

After by steel sleeve drilling indentation to projected depth, tool pipe (machine holding part and the epimerite on ground are removed Tube top end position), it then hangs out tool pipe and drilling machine is moved into next hole location.It sets up defences guardrail in aperture periphery.

Eight, pile quality detects

The detection of karst treatment cast-in-situ bored pile pile quality includes: low strain dynamic method detection of pier foundation integrality, sound wave projective method Detection of pier foundation integrality, autobalanced detection bearing capacity of pile foundation.

The characteristics of according to various detection methods itself, subway station Karst Area cast-in-situ bored pile particularity, it is various The advantage and disadvantage of detection method are summarized as follows:

1, low strain dynamic method detection of pier foundation integrality: due to only being arrived in excavation in the empty pile cutoff for excavating range internal drilling stake It can be detected after bottom plate.

2, sound wave projective method detection of pier foundation integrality: when can not excavate, can be detected drilling pile integrity, but The drilled pile descending reinforcing cage stage places sound detecting pipe and carries out related protection.

3, self-balancing approach detection of pier foundation bearing capacity: can detect the bearing capacity of drilled pile when not excavating, detection cycle compared with It is short, do not have to preloading, but should need to install load box placing the steel reinforcement cage stage and carry out related protection.

Quality control standard

360 degree of revolution full-sleeve quality control on construction execution " urban rail transit technology specification " (GB50490-2009), " architecture foundation pile technical specification " (JGJ940415-2008), " Code for design of building " (GB50007-2011), " Zhejiang Regional architecture weak base foundation design specification " (DBJ10-1-09), " reinforcement welding and control of acceptance " (JGJ18-2012).

Application example

No. 6 line first stage of the project SG6-3 bid section phoenix park erect-positions of Hangzhou Subway are in the Xihu District of Hangzhou City street Zhuan Tang Xiangshan Road and chicken hill path intersection are arranged along Xiangshan south of road north orientation.The station is two layers of underground 12.6m island station, and platform width is 12.6m, station main body a length of 274m, 15005 ㎡ of overall floorage only；Station standard paragraphs clear span is 19.9m, effective platform center Rail level buried depth is 15.2m, 3.5~4.0m of top plate earth-covering at mileage.Phoenix park station YDK4+189~YDK4+277 mileage Duan Yan Molten intense development, YDK4+132~YDK4+189 sections and the medium development of YDK4+277~YDK4+346 karst.Karst sends out area strongly 25 cast-in-situ bored piles, stake diameter 1000mm, drilling depth 42.5m~100m are designed altogether in domain.Phoenix is completed with the technology at present The construction of phoenix park station 25 cast-in-situ bored piles of karst treatment.The technology is compared to conventional Karst Area cast-in-situ bored pile (punching Hit brill) it constructs and has saved cost, accelerated construction speed, ensure that construction quality, reduce construction risk.Construction period is multiple Height by Hangzhou safe mass governor master station, construction, supervisor is praised, and faces line, Hangzhoupro pay streak karst treatment product for Hangzhoupro Tire out invaluable experience, achieves good social benefit.

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.

Claims (5)

1. a kind of strong development ultra-fine hole pile construction method in karst region, which comprises the steps of:

It surveys fixed pile center and positions, according to design drawing coordinate dimension, measure pile center, mark in the stake position of measurement, with Circular lines are drawn centered on this and according to pile diameter, jacketing machine positioning plate are lifted to stake site, error is less than ± 10mm, institute Stating jacketing machine is 360 degree of full circle swinging drill machine with casing, then host is hung to positioning plate, levels host, and lifting is put into steel sleeve First segment steel sleeve in host and gripping sleeve level machine, rotate a circle and observe bottom tooth outer ring and aforementioned circular lines weight It closes；

The steel bushing tubular pole circumgyration incision soil body sinks to drilling, clamps steel sleeve after steel sleeve machine is put into host, to cover tube bottom outer wall On the basis of observation casing external wall of upper portion verticality within the allowable range, after adjustment is vertical, base area Quality Control system cuts progress, to steel Casing is drowned into certain depth and grabs soil casing out when sinking to syzygies grab bucket with crawler crane, until design predetermined depth；

The docking of steel bushing tubular pole, the soil that cleaning has been pressed on pipe nozzle before docking lift steel sleeve and utilize upper section above nozzle Nozzle interfacing part alignment on pipe shaft outer wall, checks pipe verticality, controls in the range of 1/500, two people opposite spot welding simultaneously Fixed, securely rear two people carry out layering in opposite directions simultaneously and are fully welded operation；Then, the interfacing part and suspension centre outside pipe shaft are removed；

Fabrication of reinforcing cage and lifting, steel reinforcement cage are made by design drawing and code requirement；When lifting, upper and lower two sections steel reinforcement cage It is docked in aperture, human assistance is directed at hole location when lower cage, keeps the vertical of steel reinforcement cage；Steel reinforcement cage topmost sets positioning bar, The length for calculating positioning bar welds positioning after confirmation；When the concrete being perfused starts initial set, the vertical muscle of locating framework is cut off；

Filling concrete；

Drilling machine displacement removes the tool pipe on ground after by steel sleeve drilling indentation to projected depth, i.e. machine holds part tightly With epimerite tube top end position, then hangs out tool pipe and drilling machine is moved into next hole location；

Pile quality detection.

2. a kind of strong development ultra-fine hole pile construction method in karst region according to claim 1, it is characterised in that: when drilling, According to the soil property situation that drill hole geologic sectional view and scene are taken out, by different soil control rate of penetration and native depth is taken, according to Rig operations disk gauge pressure shows data, and torsion is up to maximum but can not creep into pushing steel bushing tubular pole, cannot continue to take again in pipe When native, into hole, continuous supplementation water maintains should have head in casing, prevents the outer soil of pipe, sand from gushing into pipe and causing settlement of foundation thing Therefore occur；When drilling, running check gauge pressure controls footage per bit, so that drill bit is freely up and down turned when creeping on hard rock It is dynamic, it often measures hole depth and forbids super grab；Reach 3 days to adjacent stake concrete and spuds in again；Must be steady when sinking to casing, avoid drill bit alloy from hitting It hits.

3. a kind of strong development ultra-fine hole pile construction method in karst region according to claim 1, it is characterised in that: the steel made Tendons skeleton is placed on smooth, dry place, when storage, each reinforcing rib and the upper contour lumps of wood of ground contact position pad；It adopts Transfer steel reinforcement cage with crane, before lifting in steel reinforcement cage temporarily plus rod, reinforce its rigidity, upper and lower two sections steel reinforcement cage aperture into Row docking, is directed at hole location by human assistance when lower cage, keeps the vertical of steel reinforcement cage, put down gently, slow play, avoid collision hole wall；It hangs During steel reinforcement cage, it is necessary to remain that reinforcing bar lorhumb line and stake axis coincide, and guarantee that stake top absolute altitude meets design requirement, steel Muscle cage topmost sets positioning bar, and the length of positioning bar is calculated by the aperture absolute altitude measured, crosschecks errorless rear welding positioning； When the concrete being perfused starts initial set, the vertical muscle of locating framework is cut off.

4. a kind of strong development ultra-fine hole pile construction method in karst region according to claim 1, it is characterised in that: concrete fills Note, filling concrete depth is not less than 1.0m for the first time, and pile concrete is poured in secondary pile hole cleaning half an hour after and carries out, and should connect Continuous perfusion is up to concrete face is higher than mouth 2.0m under conduit in pile, filling process, its lower end is embedded in depth before removing conduit every time No more than 6.0m；With the rising of hole inner concrete, need quickly to remove conduit section by section, the time is no more than 15min；In filling process In, when conduit inner concrete is discontented, when containing air, subsequent concrete should blow slowly and pour into funnel and conduit, must not be by coagulation The whole bucket of soil is poured into pipe from top to down；Pile concrete, which need to surpass, pours 0.5~1m, after reaching intensity, more than design stake top absolute altitude Part is cut with pneumatic pick.

5. a kind of strong development ultra-fine hole pile construction method in karst region according to claim 1, it is characterised in that: karst treatment The detection of cast-in-situ bored pile pile quality includes: low strain dynamic method detection of pier foundation integrality, sound wave projective method detection of pier foundation integrality, from Balance detection bearing capacity of pile foundation.