CN103485336A - Drilling pile drilling construction method of bead-type karst area - Google Patents

Abstract

The invention discloses a drilling pile drilling construction method of a bead-type karst area, wherein a drilling pile penetrates through an underground river karst cave from top to bottom. The method includes the steps of (1) measuring and sampling, (2) lowering and fixing a steel casing, and (3) drilling, wherein a percussion drill is used, drilling is carried out from top to bottom through the lowered steel casing until the percussion drill reaches a designed depth, and in the drilling process, the wall is protected through slurry; in the drilling process, when the percussion drill drills the underground river karst cave from top to bottom, the underground river karst cave is firstly processed, and then the percussion drill is used for drilling downwards; when the underground river karst cave is processed, the process is as follows: drilling of an inner protection casing installation hole, lowering of an inner protection casing, continuous drilling and plugging of a water source. The method is simple in step, reasonable in design, low in investment cost, convenient to achieve and good in construction effect, the drilling construction process of a drilling pile penetrating through the underground river karst cave can be easily, conveniently and quickly completed, cost is low and quality is high.

Description

A kind of bead string type karst area Construction method of bored pile

Technical field

The invention belongs to the Construction technology of bored pile field, especially relate to a kind of bead string type karst area Construction method of bored pile.

Background technology

Along with construction and the development of China Express Railway, railway operation is had higher requirement to high ride and high security, and must will there be new innovation in design and unit in charge of construction aspect road and bridge foundation settlement control.At Southwestern China and southeastern coastal areas complex geologic conditions, karst spreads all over, but this area is again the main artery of China's four corners of the world passage, it is again the tap of national economic development, to have more high-speed railway in this zone and pass through future, form the high ferro transportation network of the four corners of the world, so karst zone heavy caliber, the deep-water bridge pile foundation construction is the Focal point and difficult point of following high speed railway construction, scientifically study and formulate karst zone bridge pile foundation foundation construction scheme, the technical guarantee measure, process control etc., to guaranteeing construction quality, progress, safety, economic benefit all has very important significance.

Nowadays, mainly there are defect and the deficiency of following several respects while carrying out karst zone heavy caliber, deep-water bridge pile foundation construction: the first, pass through in comparatively complicated karst zone construction at bridge pile foundation, designing unit not to unit in charge of construction provide comparatively intactly, systematically theoretical foundation and construction technology file, unit in charge of construction wades across the stream by feeling the way, and the knotty problem run in construction is many, difficult, the second, perfect not for karst zone design of piled bridge foundation directive document, lack systemic, comprehensive and operability, three, high for construction technical requirement, bridge foundation sedimentation and bearing capacity, stability criterion require tight work items, and the fundamental research of lava overlay area pile foundation construction is difficult to meet the practice of construction demand, as the domestic provincial boundaries duckweed water grand bridge of the long Hunan section in Kun Kezhuan Hangzhoupro, Shanghai that is 350km for the design speed per hour, the Liling grand bridge is positioned at strong Karst Area territory, two bridges are the long auspicious cloud tunnel of interval 274m only, bridge pile foundation all is in bead string type, in the molten zone of underground river flow rock, scope is big, more than quantity, on national Passenger dedicated railway Bridge construction history, still belong to the first, and at the karst area of coverage, in solution cavity and corrosion fissure, underground water is grown, good water permeability, the water yield is large, complicated geological, particularly the Liling grand bridge is across duckweed water river, 180 meters of river width, 4～6 meters of the depth of waters, navigation at a specified future date is planned to the VII level, the part stake reaches 90 meters, indivedual pile foundations are passed through 10, eclipsed form solution cavity, high and the inclination of strata of rock strength, pass through underground river stream simultaneously, difficulty of construction is large, dangerous high, the solution cavity unstability very easily appears, Collapse Deformation, the careless slightly bit freezing that causes, bury drills, affect programming, four, for guaranteeing the construction period, on same pier, need to adopt many bench drills machine to construct, but because construction area is the karst zone, complicated geological and underground river is arranged, adopt many bench drills machine at same pier drilled pile construction, the domestic precedent that there is no simultaneously.

At present, karst zone drilled pile construction method has following four kinds: mud wall building method, static pressure chemical grouting method, casing follow-up step and NE BY ENERGY TRANSFER METHOD.Wherein, mud wall building method mainly is applicable to be not more than the small-sized solution cavity in a footpath, and concrete condition is pressed the character factor of relative position, country rock kind and the filler of solution cavity and determined.The injecting paste material that static pressure chemical grouting method adopts is normal silicate 425 cement, water glass, calcium chloride, sodium aluminate etc.The casing follow-up step is suitable for larger solution cavity and the silt particle karst of solution cavity, multilayer karst cave, volume that underflow is larger, at first puncture Upper Plate of Karst Cave by normally creeping into to approaching, drill bit is mentioned, with loop wheel machine, coordinate vibrating hammer that sinking steel protecting canister is passed to solution cavity, make the casing bottom support at solution cavity bottom or top board, spillage then in casing, continues boring, if can adopt lower interior casing or adopt the additive method leak stopping.While for large-scale solution cavity, adopting this method construction, after block stamp punctures solution cavity, hit pressure to throwing slabstone in hole and floccule and block stamp immediately, solution cavity is filled up, for the follow-up of steel casing provides support, guarantee that tilt phenomenon does not appear in the steel casing, be finally sinking steel protecting canister to design attitude or be stabilized on firm basement rock, reach the effect of guard aperture pile.The steel plate thickness that the steel casing make to adopt is according to the solution cavity size, and stake hole length is determined, generally adopts δ=8mm～10mm, the thinlyyest can not be less than 6mm, to guarantee casing, has certain Rigidity and strength, makes it indeformable.Steel casing follow-up step construct required operation and auxiliary equipment more, progress is slow, cost is high, but pore-forming and pile quality are stable, in construction, answer the factors such as integrated construction difficulty or ease Cheng Du and economic benefit to consider.The NE BY ENERGY TRANSFER METHOD construction is for karst strata, and scar tilts, rock matter soft or hard inequality, easily cause the stressed bias of bit edge pin, the treatment measures that cause the generation of the faults such as inclined to one side hole, inclined hole, curved hole and take, also be suitable for and eclipsed form bead string type karst, and pile foundation is generally longer.The operation principle of NE BY ENERGY TRANSFER METHOD be when percussive drilling approach Upper Plate of Karst Cave enter solution cavity or tiltedly during scar to things such as throwing slabstone in the stake hole and ball claies, packed height is generally the solution cavity top about 1.5m in Huo Xieyan top, top, the quality of throwing slabstone is hard and be similarly good with the hole wall rock strength, in borer drilling procedure, stroke is about 0.6m～1.0m, continue the punching operation, mix inserts through repeated stock, form fixed in solution cavity or form cylinder in hole, there is enough transmission impact energys, via hole or broken tiltedly rock, form solid simultaneously, vertically, smoother transition aperture, for following bore operation plays good guide effect.When inclined-plane tilts serious or stake position during in the solution cavity edge, creeping into middle drill bit deflection solution cavity edge one side, can't solve Huo Wan hole, inclined to one side hole problem by NE BY ENERGY TRANSFER METHOD, side-play amount is little after testing to run into this situation, should continue to throwing slabstone in hole, rubble, ball clay, block stamp hits pressure, by inclined to one side hole, and curved uprighting.

According to conventional construction, adopt the construction of casing follow-up step, meet the processing method of super-huge solution cavity fully.If but the quantity that needs the construction drill stake is more and stake is long when larger, needs the length of machined steel casing very large.Static pressure chemical grouting method is also inapplicable, although be moist plasticity and stream plasticity filler in super-huge solution cavity, uses this method effect better, and because solution cavity is too large, quantity is too many, thereby the slip casting total amount can't be estimated.To sum up, though that above two kinds of drilled pile construction methods are constructed is simple, convenient, safe, be convenient to control, but the economic benefit of input and output is disproportionate.

Summary of the invention

Technical problem to be solved by this invention is for above-mentioned deficiency of the prior art, a kind of bead string type karst area Construction method of bored pile is provided, its method step is simple, reasonable in design, input cost is lower and realize convenient, construction effect is good, can be easy, quick, low cost and high-quality complete the drilled pile drilling construction process of passing through the underground river solution cavity.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of bead string type karst area Construction method of bored pile, a underground river solution cavity is passed through in institute's construction drill stake from top to bottom, and described underground river solution cavity is the solution cavity that underground river is arranged at bottom, it is characterized in that the method comprises the following steps:

Step 1, measurement setting-out: setting-out is measured in the stake position to the construction drill stake of current institute;

Step 2, transfer and fixing steel casing: according to the measurement unwrapping wire result in step 1, transfer the steel casing and transferred steel casing is fixed; The length of described steel casing is greater than the depth of water of current institute's construction drill stake present position;

Step 3, creep into: adopt percussive drill and crept into from top to bottom by the steel casing of transferring in step 2, until creep into to projected depth, and adopt mud off in drilling process;

In drilling process, when creeping into to described underground river solution cavity from top to bottom, first described underground river solution cavity is processed, adopted again afterwards described percussive drill to continue to creep into downwards; When described underground river solution cavity is processed, process is as follows:

Step 301, interior casing installing hole drill through: adopt described percussive drill to drill through the installing hole of installing for interior casing on the riverbed on underground river;

Transferring the steel casing in step 2 is outer casing, and the internal diameter of described interior casing is greater than the stake footpath of current first drilled pile of constructing and the internal diameter that its external diameter is less than described outer casing;

Step 302, interior casing are transferred: transferred by the internal casing of described outer casing, and interior casing bottom is arranged in the installing hole that step 301 drills through;

Step 303, continue to creep into: after interior casing is transferred and put in place, then adopt described percussive drill to continue to creep into 0.8m～1.2m downwards, afterwards described percussive drill is proposed from interior casing; Now, the bed course that one deck is comprised of the rock particles after being smashed by described percussive drill is left in described interior casing bottom;

Step 304, water source shutoff: internally grouting for water blocking is carried out in the casing bottom, and makes on the rock stratum of bottom, fastening embedding underground river, interior casing bottom.

Above-mentioned a kind of bead string type karst area Construction method of bored pile, it is characterized in that: the institute's construction drill stake from top to bottom quantity of the solution cavity that passes through is two, and two described solution cavities comprise that a described underground river solution cavity and one are positioned at solution cavity below, described underground river and the inner lower solution cavity that there is no underground river; In step 3, in drilling process, when creeping into to described lower solution cavity from top to bottom, first adopt NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, adopt again afterwards described percussive drill to continue to creep into downwards.

Above-mentioned a kind of bead string type karst area Construction method of bored pile is characterized in that: the hole depth of installing hole described in step 301 is the 1m left and right; In described in step 302, casing is formed by a plurality of interior casing section assemblings, between neighbouring two described interior casing sections, with welding manner, is fixed connection; When internally casing is transferred, adopt the mode that a plurality of described interior casing sections are welded to spreading section by section to be transferred.

Above-mentioned a kind of bead string type karst area Construction method of bored pile, it is characterized in that: in step 3 in the drilling construction process, when the block stamp of described percussive drill passes through because of need that solution cavity cap rock layer breakdown another part of part rock stratum is not breakdown to be tilted to snap in breakdown solution cavity, adopt loosening blasting formula bit freezing treating apparatus processing bit freezing; Described loosening blasting formula bit freezing treating apparatus comprises from top to bottom transfers to the interior bit freezing position of boring and to by the card drill hammer, being carried out loosening demolition set, described drill hammer is for by wire rope lifting and impact the block stamp entered after solution cavity in the cap rock layer that is stuck in solution cavity, and described wire rope is stretching to be retrodeviated to the left side of boring; Described demolition set comprise dynamite container and dynamite container is vertical under put into the rope of transferring between the cap rock layer of block stamp and solution cavity, described dynamite container be suspended in transfer rope under, described dynamite container is fixed on the bottom of transferring rope, described dynamite container and transfer the right side that rope all is positioned at boring; Described dynamite container comprises that inside is equipped with the paper web of explosive and priming device and is fixed on the described paper web outside or is contained in the balancing weight in described paper web, the sealing drum of described paper web for being sealed by sealant tape.

Above-mentioned a kind of bead string type karst area Construction method of bored pile is characterized in that: in step 301, carry out before interior casing installing hole drills through, first to whether the riverbed on underground river is smooth, being soundd out; When reality is soundd out whether the riverbed on underground river is smooth, the block stamp of described percussive drill is sunk to the lower solution cavity of current state bottom, when the wire rope that connects block stamp swings serious, illustrate on the riverbed on underground river only pillar or wolf's fang rock are arranged, now need first the only pillar on riverbed or wolf's fang rock to be removed; Otherwise, when the wire rope that connects block stamp slightly swings, illustrate that the riverbed on underground river is smooth; After in described in step 302, casing is transferred and put in place, the top height of described interior casing is not less than the top height of described outer casing, and described percussive drill is positioned at the inside bottom of casing; Described interior casing is coaxial laying with described outer casing.

Above-mentioned a kind of bead string type karst area Construction method of bored pile is characterized in that: when in step 304, internally grouting for water blocking is carried out in the casing bottom, the grouting for water blocking material adopted is polyurethane injecting paste material or cement-silicate biliquid slurry; When internally grouting for water blocking is carried out in the casing bottom, first Grouting Pipe is inserted into to interior casing bottom from top to bottom, adopts afterwards grouting pump and by described Grouting Pipe, described grouting for water blocking material pump is delivered to interior casing bottom.

Above-mentioned a kind of bead string type karst area Construction method of bored pile is characterized in that: in step 3, in drilling process, when oblique rock is carried out to drilling construction, the block stamp of described percussive drill is replaced by reinforced block stamp; Described reinforced block stamp comprises and being vertically to the middle part column of laying and a plurality of tooth that rushes along the circumferential direction evenly be laid on the column lateral wall of middle part, and described middle part column is the cylindrical, massive steel column, and the diameter of described middle part column is 500mm～800mm; A plurality of described structure and sizes of rushing tooth are all identical, and a plurality of described teeth that rush are the rail that top is weldingly fixed on column middle and upper part, middle part, and the laying of a plurality of described rail is highly all identical; Between a plurality of described rail and middle part column, all by gusset, be fastenedly connected; The bottom height of described middle part column is not less than the bottom height of a plurality of described rail, and a plurality of described rail all are and are tilted to laying, and the angle between a plurality of described rail and middle part column is 15 °～20 °; The vertical height H of described rail is 1500mm～2000mm.

Above-mentioned a kind of bead string type karst area Construction method of bored pile, it is characterized in that: adopt described percussive drill to carry out from top to bottom in drilling process, when creeping into to distance described underground river solution cavity or 1m left and right, described lower solution cavity top, reduce immediately the impact stroke of described percussive drill, with short stroke, fast frequency mode, puncture described underground river solution cavity or described lower solution cavity.

Above-mentioned a kind of bead string type karst area Construction method of bored pile, it is characterized in that: in step 3, adopt described percussive drill to carry out from top to bottom in drilling process, the proportion of mud that mud off adopts is 1.2～1.5, viscosity is 22s～30s, sand factor≤4%, pH value are 8～10 and colloidity >=95%;

Creep into to projected depth, also need institute's moulding boring is carried out to hole clearly; Actual while carrying out clearly hole, first the block stamp of described percussive drill is increased to left back apart from 20cm at the bottom of institute's moulding drilling hole, at the bottom of pump line being inserted into to institute's moulding drilling hole again, carry out anti-circulation cleaning hole by described pump line afterwards, until in institute's moulding drilling hole, mud density is less than 1.1g/cm ³.

Above-mentioned a kind of bead string type karst area Construction method of bored pile is characterized in that: while adopting NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, by the interior throwing filling mixture of boring lower solution cavity is carried out to backfill; Described lower solution cavity be hole higher primary school in the small-sized solution cavity of 2m, hole high for the medium-sized solution cavity of 2m～5m or hole tall and big in the large-scale solution cavity of 5m;

Instantly the hole higher primary school of solution cavity is when 2m, and the filling mixture of institute's throwing is the first filling mixture be comprised of slabstone and ball clay; In described the first filling mixture the mass ratio of slabstone and ball clay be (0.8～1.2) ︰ 1, in described the first filling mixture, the particle diameter of slabstone is 10cm～15cm;

Instantly the hole of solution cavity is high while for 2m～5m and inside, having stream to mould the shape filler, by throwing the second filling mixture in institute's boring in step 3, lower solution cavity is carried out to back-filling in layers and also tamps; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the second filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the second filling mixture; Described the second filling mixture is mixed by slabstone, rubble and ball clay, and in described the second filling mixture, the mass ratio of slabstone, rubble and ball clay is (1.8～2.2) ︰ (0.8～1.2) ︰ 2; In described the second filling mixture, the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is below 7cm;

When solution cavity is the high 2m～5m in hole and inner non-filler empty instantly, in boring the filling concrete lower solution cavity is carried out to backfill;

Instantly the hole of solution cavity is tall and big when moulding shape and/or stream in 5m and inside and moulding the shape filler, by boring throwing the 3rd filling mixture lower solution cavity is carried out to back-filling in layers compacting; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the 3rd filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the 3rd filling mixture; Described the 3rd filling mixture is mixed by piece stone, ball clay, slabstone and rubble or is mixed by piece stone, slabstone, rubble and packed clay, in described the 3rd filling mixture, the mass ratio of piece stone, ball clay, slabstone and rubble is (1.8～2.2) ︰ (1.8～2.2) ︰ (0.8～1.2) ︰ 1, and in described the 3rd filling mixture, the mass ratio of piece stone, slabstone, rubble and packed clay is (1.8～2.2) ︰ (0.8～1.2) ︰ (0.8～1.2) ︰ 1; In described the 3rd fill concrete, the diameter of piece stone is the 40cm left and right, and the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is the 5cm left and right.

The present invention compared with prior art has the following advantages:

1, method step is simple, reasonable in design and to drop into construction cost lower, can effectively reduce every input costs such as labour cost, cost of materials, machinery expense, overhead cost.

2, fast and construction period of construction speed can be guaranteed, easy construction, and construction quality is easy to guarantee, and work progress safety, reliable.

3, the solution cavity treatment design rationally, the input construction cost is low and construction effect good, broken through the conventional construction method that large-scale solution cavity adopts the construction of casing follow-up step, first adopt aperture steel casing to carry out mud off, adopt afterwards NE BY ENERGY TRANSFER METHOD to carry out drilling construction, saved a large amount of casings steel used and processing, mounting cost.

4, the filling batch component that NE BY ENERGY TRANSFER METHOD adopts and proportion design are rationally, filling is convenient and filling effect is good, can effectively guarantee the solution cavity treatment effect, and input cost is lower.

5, pass through underground river stream solution cavity method reasonable in design, realize convenient and treatment effect is good, processing procedure safety, reliable, adopt short casing to follow up to step embedding rock 1m at the bottom of solution cavity, the shutoff water source, continue to creep into.

In sum, the inventive method step is simple, reasonable in design, input cost is lower and realize convenient, construction effect is good, can be easy, quick, low cost and high-quality complete the drilled pile drilling construction process of passing through the underground river solution cavity.

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

The accompanying drawing explanation

Fig. 1 is method flow block diagram of the present invention.

Fig. 2 is Construction State schematic diagram of the present invention.

The structural representation that Fig. 3 is the reinforced block stamp of the present invention.

The top view that Fig. 4 is Fig. 3.

The use view that Fig. 5 is loosening blasting formula bit freezing treating apparatus of the present invention.

Description of reference numerals:

1-underground river; 1-1-middle part column; 1-2-rail;

1-3-gusset; 2-outer casing; 2-1-dynamite container;

2-2-transfer rope; 2-3-drill hammer; 3-interior casing;

5-plugged zone.

The specific embodiment

A kind of bead string type karst area Construction method of bored pile as shown in Figure 1, a underground river solution cavity is passed through in institute's construction drill stake from top to bottom, and described underground river solution cavity is the solution cavity that underground river 1 is arranged at bottom, refers to Fig. 2, and the method comprises the following steps:

Step 1, measurement setting-out: setting-out is measured in the stake position to the construction drill stake of current institute.

During practice of construction, measuring unwrapping wire must be accurate, and pile position deviation will meet the requirements.Unwrapping wire on request, once, after pile, if pile position deviation is larger, change to the stressed of some.Adopt the total powerstation unwrapping wire, repeatedly check in the unwrapping wire process, compound multiple spot is controlled.Take again to proofread and correct off normal, in order to avoid deviation is large, cause the duration to lag behind and the fund waste.

After the measurement unwrapping wire completes, due to karst zone geologic anomaly complexity, although geology has been carried out encrypting probing research, also be difficult to guarantee to feel out the situation, therefore each drilled pile carries out the steel sheet pile of 2 couples of 4 long 10m of percussive drill front laying in place of drilling construction, the base of impact rig is reinforced, and makes percussive drill steady, in case percussive drill immerge and inclination during borehole collapse.

Step 2, transfer and fixing steel casing: according to the measurement unwrapping wire result in step 1, transfer steel casing 2 and transferred steel casing 2 is fixed; The length of described steel casing 2 is greater than the depth of water of current institute's construction drill stake present position.

In the present embodiment, when transferred steel casing 2 is fixed, with embedding manner, described steel casing 2 is fixed.While with embedding manner, described steel casing 2 being fixed, adopt clay by the compacting of the surrounding of fixed steel casing 2, be subjected to displacement to prevent described steel casing.

In the present embodiment, steel casing 2 is buried in stake aperture, hole at each the first drilled pile underground, the long 8m of steel casing 2, and its length determined according to geology, groundwater table, the depth of water 5m of institute's construction drill pile driving construction position, the cofferdam used of constructing exceeds water surface 2m, the internal diameter of steel casing 2 is than the stake large 20cm in footpath and its wall thickness δ=10mm of first drilled pile of constructing, and steel plate rolls and forms, and steel casing 2 is buried top underground and exceeded water surface 30cm, in case, outside the mud overfolw hole, the surface water flows in the stake hole.

Step 3, creep into: adopt percussive drill and crept into from top to bottom by the steel casing 2 of transferring in step 2, until creep into to projected depth, and adopt mud off in drilling process.

In drilling process, when creeping into to described underground river solution cavity from top to bottom, first described underground river solution cavity is processed, adopted again afterwards described percussive drill to continue to creep into downwards; When described underground river solution cavity is processed, process is as follows:

Step 301, interior casing installing hole drill through: adopt described percussive drill to drill through the installing hole of installing for interior casing 3 on the riverbed on underground river 1.

Transfer steel casing 2 in step 2 for outer casing, the internal diameter of described interior casing 3 is greater than the stake footpath of current first drilled pile of constructing and the internal diameter that its external diameter is less than described outer casing.

Step 302, interior casing are transferred: transferred by the internal casing 3 of described outer casing, and interior casing 3 bottoms are arranged in the installing hole that step 301 drills through.

Step 303, continue to creep into: after interior casing 3 is transferred and put in place, then adopt described percussive drill to continue to creep into 0.8m～1.2m downwards, afterwards described percussive drill is proposed from interior casing 3; Now, the bed course that one deck is comprised of the rock particles after being smashed by described percussive drill is left in described interior casing 3 bottoms.Simultaneously, also contain clay in described bed course.

Step 304, water source shutoff: internally grouting for water blocking is carried out in casing 3 bottoms, and makes on the rock stratum of 1 bottom, interior casing 3 fastening embedding underground river, bottom.

In the present embodiment, described percussive drill is the CZ-8 percussive drill.Adopt the reason of CZ-8 percussive drill to be the architectonic particularity in karst zone, covering layer, weathered rock formation, whole rock stratum, eclipsed form solution cavity, bead string type solution cavity will be passed through in the stake hole, the shape scars such as oblique rock, sawtooth pattern, wolf's fang type, only post rock are arranged in hole, and rock strength is quite hard, surface is smooth especially.Adopt the full circle swinging percussive drill and revolve that to dig the rate of penetration of percussive drill in covering layer, weathered rock formation, whole rock stratum be that percussive drill is more than 4～5 times.After creeping into karst, the solution cavity bottom is uneven, and the shape rock is in different poses and with different expressions as mentioned above in solution cavity inside.

Full circle swinging percussive drill and revolve the drill bit that digs percussive drill because being subject to the rise and fall cutting collision of rock of solution cavity bottom height, the applied pressure of percussive drill own, make drill bit produce batch (-type) consumingly and vibrate in addition; Along with rotatablely moving of percussive drill, drill bit produces batch (-type) vibration consumingly and is passed to drilling rod, makes the windup distortion.If running into the scar full circle swinging percussive drill of oblique rock or soft or hard inequality is better than to revolve and digs percussive drill, because the cutter of full circle swinging percussive drill is placed in the sleeve pipe lower end, and between sleeve pipe, be to be rigidly connected, vertical bulk strength is large, although drill bit is subject to the batch (-type) vibration, but sleeve pipe rotates at drill hole inner wall, the restriction that is subject to hole wall is unlikely to move along oblique rockslide.Revolve and dig percussive drill because drill pipe diameter is little, run into 60 ° of oblique scars, tiltedly scar is smooth in addition, the drill bit intermittent control shaking, and along tiltedly scar slippage, although the jackstone correction, drilling rod and drill bit junction torsional deformation.Thereby full circle swinging percussive drill and revolve and dig percussive drill and creeping into the middle following several respects defect that exists: the power impact rig rotary system that the batch (-type) vibration the first, be subject to produces has caused serious infringement; The second, in drilling process, drill bit is subject to the vibration of strong shock and makes the drill bit cutter be easy to wearing and tearing and destroy; Three, it is long that the percussive drill drill bit damages rear drilling rod lifting repairing efficiency, and each repair time is all more than 10 days; Four, revolve that to dig percussive drill mud off in drilling process bad, backfill slabstone and earth are well not fixed, easily produce collapse hole when promoting the drilling rod bit change or changing drilling rod; Five, not compacting of filler, void content is large, easily produces spillage during concreting.

CZ-8 type impact type Churn drill function makes up the full circle swinging percussive drill and revolves defect and the deficiency of digging percussive drill, in cover sand gravel and whole Rock penetrating, target efficiency is low, in the pile foundation construction of karst zone, efficiency is dug percussive drill higher than the full circle swinging percussive drill with revolving, reason is: the first, Churn drill is to become the potential energy work done by kinetic transformation, power conversion, and potential energy is controlled; The second, simple in structure, convenient operation, cost is low; Three, as long as method of operating is proper, with effective measures, in the solution cavity boring procedure, various grotesque rocks can tackle; Four, after solution cavity backfill slabstone, earth under the effect of potential energy impact force, filler is subject to External Force Acting, extruding is mobile, rearrange combination, particularly crack, crack can be tamped and be filled up, and add the smooth of mud and infiltration, make it form new integral body fixed, mud off is good, also can spillage in concreting process.In addition, percussive drill is due to simple structure, and acquisition expenses is few, and the equipment depreciation expense is little, and the maintenance expense is low, and often maintenance items is few.As change the friction clutch-plate, and change steel rope, drill bit maintenance repair welding is once got over, and operating personnel are few, and power is 75kw, is that the full circle swinging percussive drill digs percussive drill 1/4 power consumption with revolving.To sum up, the most economical, most economical, the most durable, the most effective rig of percussive drill.

In addition, according to the required impact force of the fractured rock calculated, be 42.6kN, thereby to select quality be 5000kg, i.e. the block stamp of 5T.

In the present embodiment, in step 3 in drilling process, during mud off, the proportion of the mud that adopts is 1.2～1.5, viscosity is 22s～30s, sand factor≤4%, pH value are 8～10 and colloidity >=95%.

Actual while carrying out drilling construction, after steel casing 2 sinks down into scar, use the percussive drill reciprocating impact, by the soil in punching, stone is broken or clamp-on in hole wall, with high pressure slurry pump, rock ballast is suspended and portals.

Mud off is exactly according to the kind difference of solution cavity inner stuffing and stream plasticity, add respectively by a certain percentage caustic soda in mud, cement, wood sawdust, straw bag, the mixed materials such as sheet (broken) stone, utilize the impact of drill bit to fiddle with effect, packing material is clamp-oned in solution cavity and Karst Fissures together with dense mud, form the continuous drilling path of some strength, form the hole wall closed-loop in the continuous drilling operation, reach the effect of mud off, concrete condition is pressed the relative position of solution cavity, Rock Species, the factors such as the character of filler are determined, the preparation situation of the mud that mud off adopts under different condition is in Table 1:

The preparation table of table 1 mud that mud off adopts

The effect of mud off method processing karst depends on the preparation quality of mud, therefore when preparing, mud should note the selection requirements of various batchings, clay is the primary raw material of preparation mud, answer tool aquation piece, the characteristics such as yield is strong, viscosity is large, sand factor is low, the General Requirements colloidity is not less than 95%, and sand factor is less than 4%, yield is greater than 2.5L/kg, and index of plasticity is not less than 20.When the solution cavity inner stuffing is that fine sand or stream are while moulding material, mix appropriate cement in mud, can improve the impermeabilisation ability of mud, strengthen anti-retaining wall function, prevent collapse hole spillage function, the consumption of cement is 15%～20% of clay quality, and caustic soda has maintenance and improves the effect of mud viscosity, for processing the hole wall spillage, effect is preferably arranged, generally press 2%～3% of clay quality and use.Mix in right amount wood chip in mud, can improve its suspending power, meet the clear hole requirement of karst strata slag.The use of sheet (broken) stone can be played the reinforcement effect of solution cavity hole wall skeleton, generally selects slabstone and the following rubble of particle diameter 7cm of particle diameter 15～25cm.The selection of material also can be suited measures to local conditions, and selects other material, to reach the best results of processing solution cavity, is advisable.

During drilling construction, note observing the block stamp of percussive drill in the percussion drilling process and the swing situation of wire rope in step 3.Because the swing of block stamp and wire rope directly reflects the energy exchange situation of block stamp and rock, if drop hammer steadily, mean that the energy exchange of block stamp and rock is good; The hour hammer that drops hammer is not steady, and wire rope swings serious, illustrates that the switching channel of energy is not smooth, and block stamp has consumed sizable energy in swing process, and impact effect is poor, so operating personnel should observe the swing situation of block stamp and wire rope while dropping hammer at any time.When the shakiness of dropping hammer, wire rope seriously swings, and is in rock stratum, has illustrated that in oblique rock appearance or hole, rock strength differs, and has two kinds of rocks at least, makes the unbalance stress of block stamp and rock.If the swing position of wire rope and hammer is in the solution cavity inner bottom part, illustrate in hole the wolf's fang rock is arranged, sawtooth rock or only uneven situation at the bottom of the holes such as stone, erratic boulder exposure, the trend that produces inclined hole and curved hole is arranged.Block stamp top is crooked, clashes into hole wall, will cause hole expansibility significantly to increase, now should stop impacting, the throwing filler is to the above 1m～2m of hole deviation scar partially in time, then percussion drilling again, adjust the block stamp stroke, low hammer high frequency, close hitting, until wire rope and block stamp steadily creep into simultaneously.In addition, note loosening uniformly the length of wire rope in impact process, Soft Soil Layer loosens 5cm～8cm at every turn, loosen 3cm～5cm at the rock solid bed at every turn, prevent that slack rope is very few, form the hammer that fans the air, make rig, support and wire rope be subject to excessive impact load to cause damage.

In the present embodiment, the institute's construction drill stake from top to bottom quantity of the solution cavity that passes through is two, and two described solution cavities comprise that a described underground river solution cavity and one are positioned at solution cavity below, described underground river and the inner lower solution cavity that there is no underground river 1; In step 3, in drilling process, when creeping into to described lower solution cavity from top to bottom, first adopt NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, adopt again afterwards described percussive drill to continue to creep into downwards.Described underground river solution cavity is the 4# solution cavity, and described lower solution cavity is the 2# solution cavity.

During practice of construction, adopt described percussive drill to carry out from top to bottom in drilling process, when creeping into to distance described underground river solution cavity or 1m left and right, described lower solution cavity top, reduce immediately the impact stroke of described percussive drill, with short stroke, fast frequency mode punctures described underground river solution cavity or described lower solution cavity, prevent that impact force is excessive and cause collapse hole or bit freezing, once mud sinks fast, will be by the performances of rock of different karst, to shift to an earlier date ready mud and mend rapidly slurry, Quick bores simultaneously, filling mixture is thrown in and the repeated stock extruding, until pass through smoothly solution cavity.

In the present embodiment, when creeping into to distance, need pass through solution cavity top 1m the time, reduce immediately the impact stroke of described percussive drill.

When the actual impact stroke to described percussive drill is reduced, by piercing drilling depth, progressively successively decrease, reduce to 1.5m from 2m, then reduce to 1m from 1.5m, finally from 1m, reduce to 0.5m.

Adopt in step 3 in the percussive drill drilling process, often creep into 5cm～10cm scarfing cinder once in competent bed when creeping into, often creep into while creeping in weathered rock formation that 15cm～the 30cm scarfing cinder once; And, often creep into 4m～6m, adopt the verify device to carry out verify one time.Actual while carrying out scarfing cinder, first block stamp is proposed, then change and draw the slag cylinder and put into and put at the bottom of hole to draw and get boring mud.

In addition, in the percussion drilling process, must verify.The verify device is connected into cage with steel bar welding, external diameter is determined according to the aperture of examine boring, the 4-6 that length is aperture doubly, often creep into 4m～6m, when the easy shrinkage cavity section of solution cavity backfill layer or rock mass replacing repairing block stamp are passed through in boring, must carry out verify, the position that can not sink to former drilling depth or stay cord as the verify device is offset, curved hole may occur, the situations such as inclined hole or shrinkage cavity, should revise immediately.

In the whole hole of karst zone construction drill stake, at first to determine the thickness of bearing stratum, the complete basement rock that it has been generally acknowledged that three times of stake footpaths or be not less than 5m is fully reliably

Creep in step 3 to projected depth, also need institute's moulding boring is carried out to hole clearly; Actual while carrying out clearly hole, first the block stamp of described percussive drill is increased to left back apart from 20cm at the bottom of institute's moulding drilling hole, at the bottom of pump line being inserted into to institute's moulding drilling hole again, carry out anti-circulation cleaning hole by described pump line afterwards, until in institute's moulding drilling hole, mud density is less than 1.1g/cm ³.Behind clear hole, note keeping head height, with anti-collapse.

Behind clear hole, in institute's moulding drilling hole, the proportion of mud is 1.03～1.1, viscosity is that 17s～20s, sand factor are less than 2%, colloidity be greater than 98% and sediment thickness be not more than 5cm.

In the present embodiment, while adopting NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, by the interior throwing filling mixture of boring lower solution cavity is carried out to backfill; Described lower solution cavity be hole higher primary school in the small-sized solution cavity of 2m, hole high for the medium-sized solution cavity of 2m～5m or hole tall and big in the large-scale solution cavity of 5m.

Instantly the hole higher primary school of solution cavity is when 2m, and the filling mixture of institute's throwing is the first filling mixture be comprised of slabstone and ball clay; In described the first filling mixture, the mass ratio of slabstone and ball clay is that (0.8～1.2) ︰ 1, in described the first filling mixture, the particle diameter of slabstone is 10cm～15cm.

Instantly the hole of solution cavity is high while for 2m～5m and inside, having stream to mould the shape filler, by throwing the second filling mixture in institute's boring in step 3, lower solution cavity is carried out to back-filling in layers and also tamps; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the second filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the second filling mixture; Described the second filling mixture is mixed by slabstone, rubble and ball clay, and in described the second filling mixture, the mass ratio of slabstone, rubble and ball clay is (1.8～2.2) ︰ (0.8～1.2) ︰ 2; In described the second filling mixture, the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is below 7cm.

When solution cavity is the high 2m～5m in hole and inner non-filler empty instantly, in boring the filling concrete lower solution cavity is carried out to backfill.

Instantly the hole of solution cavity is tall and big when moulding shape and/or stream in 5m and inside and moulding the shape filler, by boring throwing the 3rd filling mixture lower solution cavity is carried out to back-filling in layers compacting; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the 3rd filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the 3rd filling mixture; Described the 3rd filling mixture is mixed by piece stone, ball clay, slabstone and rubble or is mixed by piece stone, slabstone, rubble and packed clay, in described the 3rd filling mixture, the mass ratio of piece stone, ball clay, slabstone and rubble is (1.8～2.2) ︰ (1.8～2.2) ︰ (0.8～1.2) ︰ 1, and in described the 3rd filling mixture, the mass ratio of piece stone, slabstone, rubble and packed clay is (1.8～2.2) ︰ (0.8～1.2) ︰ (0.8～1.2) ︰ 1; In described the 3rd fill concrete, the diameter of piece stone is the 40cm left and right, and the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is the 5cm left and right.In the present embodiment, in described the 3rd fill concrete, the diameter of piece stone is 40cm, and the particle diameter of rubble is 5cm.

In the present embodiment, in described the first filling mixture, the mass ratio of slabstone and ball clay is 1 ︰ 1, in described two filling mixtures, the mass ratio of slabstone, rubble and ball clay is 2 ︰ 1 ︰ 2, in described the 3rd filling mixture, the mass ratio of piece stone, ball clay, slabstone and rubble is 2 ︰ 2 ︰ 1 ︰ 1, and in described the 3rd filling mixture, the mass ratio of piece stone, slabstone, rubble and packed clay is 2 ︰ 1 ︰ 1 ︰ 1.During practice of construction, can be according to specific needs, the raw material proportioning of described the first filling mixture, the second filling mixture and the 3rd filling mixture is adjusted accordingly.

Instantly the hole higher primary school of solution cavity is when 2m, in step 3 in boring the throwing filling mixture lower solution cavity is carried out to backfill, until be backfilled to lower solution cavity over top 1m left and right.Afterwards, adopt close the hitting of the low hammer of percussive drill, until in hole, mud is normal, impact smoothly via hole.In the present embodiment, until be backfilled to lower solution cavity over top 1m.

Instantly the hole of solution cavity is high when 2m～5m and inside moulding shape and/or stream and mould the shape filler, adopts described the second filling mixture to carry out back-filling in layers compacting to lower solution cavity, until be backfilled to lower solution cavity over top 1m left and right.After each raising, all adopt described percussive drill repeated stock to be tamped, and stop impacting after the cement mortar of being injected in advance until the internal void of institute's backfill the second filling mixture or the two slurry plugs of cement-silicate.Back-filling in layers complete and until institute's backfill the second filling mixture and institute's injected water cement mortar or cement-silicate is fixed be integrated after, then adopt percussive drill to continue to creep into downwards.In the present embodiment, adopt described the second filling mixture to carry out back-filling in layers compacting to lower solution cavity, until be backfilled to lower solution cavity over top 1m.Back-filling in layers completes and after institute's backfill the second filling mixture and institute's injected water cement mortar or the intensity of cement-silicate after fixed reach 2.5MPa, then adopts percussive drill to continue to creep into downwards.It is silt particle that described stream is moulded the shape filler.

In the present embodiment, instantly the hole of solution cavity is high while for 2m～5m and inside, having stream to mould the shape filler, after described lower solution cavity is punctured by block stamp, inject a certain amount of cement mortar in solution cavity downwards rapidly, and add a certain proportion of water glass liquid, it is mixed with the hole inner stuffing as early as possible, again to throwing slabstone in hole, rubble and ball clay make its mixing, back-filling in layers, each raising 2m, then layering is impacted filler with the little stroke of percussive drill, it is squeezed to hole body periphery, form the outer retaining wall of mud rubble, cement mortar stops impacting after the slabstone space is stopped up, after 24 hours, after the fixed and intensity such as cement mortar and slabstone reaches 2.5MPa, continue again to impact via hole.

Simultaneously, the hole of solution cavity is high when 2m～5m and inside moulding shape and/or stream and mould the shape filler instantly, also need to the cement mortar or the cement-silicate pair slurries that inject in boring be added with retarding agent.

In the present embodiment, instantly (general rock mass strength is high in the cavity that solution cavity is the high 2m～5m in hole and inner non-filler, not in easy-weathering and hole without decomposed rock mud and fine sand and so on) time, described concrete is the sheet stone concrete, and the slabstone that described stone concrete is 15cm～25cm by C30 concrete and particle diameter mixes; While adopting described stone concrete to carry out backfill to lower solution cavity, by concrete pumping equipment in step 3 inject the C30 concrete in boring, and inject the concrete while of C30, to the throwing particle diameter slabstone that is 15cm～25cm in boring, and by described percussive drill repeated stock, injected C30 concrete is mixed with institute throwing slabstone; After described slabstone concrete setting, then adopt percussive drill to continue to creep into downwards.

And, when solution cavity is the high 2m～5m in hole and inner non-filler empty instantly, in boring described stone concrete of filling lower solution cavity is carried out to backfill, until be backfilled to lower solution cavity over top 1m left and right.In the present embodiment, by described percussive drill repeated stock, injected C30 concrete mixed with institute throwing slabstone and make C30 concrete and the inner tight of institute's throwing slabstone, after 24 hours, intensity reaches and necessarily requires backlash to hit via hole.And, to described stone concrete of filling when lower solution cavity is carried out to backfill, until be backfilled to lower solution cavity over top 1m in boring.

In the present embodiment, the hole of solution cavity is tall and big instantly when moulding shape and/or stream in 5m and inside and moulding the shape filler, in described boring when described the 3rd filling mixture of throwing, also need to throw in straw in boring.

In the present embodiment, the hole of solution cavity is tall and big instantly when moulding shape and/or stream in 5m and inside and moulding the shape filler, adopts described the 3rd filling mixture to carry out back-filling in layers compacting to lower solution cavity, until be backfilled to lower solution cavity over top 2m～3m; After each raising, all adopt described percussive drill repeated stock to be tamped, after cement mortar or the two slurry plugs of cement-silicate that the internal void of institute's backfill the 3rd filling mixture is injected in advance, stop impacting; Back-filling in layers complete and until institute's backfill the 3rd filling mixture and institute's injected water cement mortar or cement-silicate is fixed be integrated after, then adopt percussive drill to continue to creep into downwards.

In the present embodiment, the hole of solution cavity is tall and big instantly when moulding shape and/or stream in 5m and inside and moulding the shape filler, moulds shape and/or stream in described lower solution cavity and moulds the volume of shape filler and account for 1/2～3/4 of lower solution cavity volume.According to Use of Geophysical Data, see, lower solution cavity hole inner volume 3/4 is filler, and filler is the silt particle graininess, and filler the first half is moist, and the latter half is that stream is moulded shape.After described lower solution cavity is breakdown, inject concrete mortar in boring, and add in right amount water glass, it is mixed with the hole inner stuffing, to fill block stone throwing, ball clay, slabstone, rubble and straw in hole, straw adds fashionable trembling out by hand with building stones, clay and throws in simultaneously again.Each throwing height is 2m, close the hitting of low hammer, until throwing to the above 2m～3m in solution cavity top, stops impacting, after 24 hours, the hole inner stuffing is bonded to the some strength requirement, impacts via hole.

While nowadays carrying out the solution cavity processing, according to the physical property of size, shape and the solution cavity inner stuffing (cavity) of Geologic Structure Feature and solution cavity in zone, solution cavity is divided into to four classes, refers to table 2:

Table 2 solution cavity development degree classification chart

In the present embodiment, the tall and big lower solution cavity in 5m in hole comprises two kinds, large-scale solution cavity and super-huge solution cavity.

During practice of construction, the processing of solution cavity must base area pledge spy data be carried out, and for the solution cavity of different sizes, heterogeneity, different fillings, takes different treatment measures.At first the geology Use of Geophysical Data of will analyzing and researching, determine the size of solution cavity and a stake residing position, hole, solution cavity, filler and performance in the intensity of solution cavity rock stratum and solution cavity.In the present embodiment, described lower solution cavity is super-huge solution cavity, and the hole height is 21.48m, is half filler in hole, half cavity, and filler is plasticity, stream plasticity, and filler is most of for moulding shape, near the solution cavity bottom, for stream, moulds shape, and rock mass strength is 500MPa～800MPa.

In the present embodiment, when super-huge solution cavity is processed, after block stamp punctures lower solution cavity, inject a large amount of concrete mortars in hole, suitably increase cement proportion, and increase a certain proportion of retarding agent in concrete mortar, make it in backfill and compacting process, extend setting time, increase permeability, in compacting and jackstone process, the concrete mortar slurries are well mixed with former filler in hole; In addition, because super-huge solution cavity backfill amount is large, throwing and compacting time are relatively long, filler in filling and compacting process in hole is all the time in mobile and squeezed state, after injecting concrete mortar, to throwing in piece stone, slabstone, rubble and packed clay in hole and mass ratio is 2 ︰ 1 ︰ 1 ︰ 1, throw in straw appropriate and tremble out with building stones while throwing in and synchronously throw in simultaneously.The particle diameter of throwing in building stones is: piece stone is 40cm, slabstone is 15-20cm, rubble is the 5cm left and right, and each packed height is 2m, and a certain amount of concrete mortar reinjects after close the hitting of low hammer, and then a certain proportion of filler of throwing, layering is filled and compacting, until fill the above 2m～3m in solution cavity top, stops impacting, after 24 hours, its intensity starts percussive drilling while reaching 2.5MPa.Forbid the weight strong rammer in throwing and compacting process, the block stamp stroke can not surpass 1m, because what produce in block stamp compacting process hits the power effect of shaking, make building stones push slippage in slurries, such slippage (displacement) process is also to fill the process that building stones rearrange combination.After relatively large stone displacement is stable, the be squeezed effect of power of slabstone and rubble, play and fill space and the support of piece stone is leveled up to effect, and appropriate straw has played the net sheet effect mutual restraining function of building stones (to), its filler in punch process can not be caved in, but control injected volume.If weight strong rammer in filling and compacting process, easily make the stone of filling fly upward in hole, well with slurries, do not mix, form irregular body, void content is also large, so easy collapse hole in the percussive drilling process, void content is large, in the concreting process, easily spillage, produce pile breaking phenomenon.

After hole inner stuffing intensity reaches 2.5MPa, perform mud by above-mentioned requirements, note match ratio and concentration.Drop into rubble and straw during percussive drilling in the stake hole, too much unsuitable.Rubble is filled the hole wall duck eye in extrusion process.The straw rear formation fiber that is hit adheres to hole wall, makes the mud off better effects if.

The hole depth of installing hole described in step 301 is the 1m left and right.

In the present embodiment, the hole depth of described installing hole is 1m.During practice of construction, can be according to specific needs, the hole depth of described installing hole is adjusted accordingly.

In the present embodiment, described in step 302, interior casing 3 is formed by a plurality of interior casing section assemblings, between neighbouring two described interior casing sections, with welding manner, is fixed connection.When in step 302, internally casing 3 is transferred, adopt the mode that a plurality of described interior casing sections are welded to spreading section by section to be transferred.

The wall thickness of the casing of steel described in step 22 is 10mm, and the wall thickness of described interior casing 3 is 8mm, the internal diameter of described interior casing 3 than the stake large 20cm in footpath and its external diameter of current first drilled pile of constructing than the little 5cm of the internal diameter of steel casing 2.During practice of construction, can according to specific needs, the wall thickness of steel casing 2 and interior casing 3, the internal diameter of interior casing 3 and the internal diameter of external diameter and steel casing 2 be adjusted accordingly.

In the present embodiment, after described in step 302, interior casing 3 is transferred and put in place, the top height of described interior casing 3 is not less than the top height of described outer casing, and described percussive drill is positioned at the inside bottom of casing 3.And described in step 302, interior casing 3 is coaxial laying with described outer casing.

During practice of construction, in step 301, carry out before interior casing installing hole drills through, first to whether the riverbed on underground river 1 is smooth, being soundd out.When reality is soundd out whether the riverbed on underground river 1 is smooth, the block stamp of described percussive drill is sunk under current state and needs to pass through the solution cavity bottom, when the wire rope that connects block stamp swings serious, illustrate on the riverbed on underground river 1 only pillar or wolf's fang rock are arranged, now need first the only pillar on riverbed or wolf's fang rock to be removed; Otherwise, when the wire rope that connects block stamp slightly swings, illustrate that the riverbed on underground river 1 is smooth.

In the present embodiment, in step 303, after interior casing 3 is transferred and put in place, then adopt described percussive drill to continue to creep into 1m downwards, afterwards described percussive drill is proposed from interior casing 3.

When in step 304, internally grouting for water blocking is carried out in casing 3 bottoms, the grouting for water blocking material adopted is polyurethane injecting paste material or cement-silicate biliquid slurry, after water blockoff, corresponding to a plugged zone 5 of interior casing 3 bottoms formation.

In the present embodiment, described cement-silicate biliquid slurry is the biliquid slurry of the ultra-fine high-early (strength) cement of HSC and water glass composition.Described polyurethane injecting paste material is water soluble polyurethane leak-stopping agent.

In the present embodiment, when in step 304, internally grouting for water blocking is carried out in casing 3 bottoms, first Grouting Pipe is inserted into to interior casing 3 bottoms from top to bottom, adopts afterwards grouting pump and by described Grouting Pipe, described grouting for water blocking material pump is delivered to interior casing 3 bottoms.

To sum up, the 2# solution cavity is arranged below the basal bed due to underground river 1 solution cavity of living in, therefore determine and adopt short casing follow-up construction, shutoff water source after 3 follow-ups of interior casing are dark to embedding rock 1m at the bottom of hole, the follow-up of termination casing, prevent that the river crossfire from bringing very big inconvenience to construction to the 2# solution cavity of lower floor, adopts the energy exchange method to continue to creep into afterwards.

Through souning out, the bottom, riverbed on underground river 1 is substantially smooth, thereby take fierce impact will give prominence to rock smash the leveling continue to creep into to 1m, the interior casing 3 of making is welded to spreading section by section, be lowered to the solution cavity bottom, whether interior casing will be adjusted measurement after getting well for 3 times vertical, after all meet the requirements, continue when percussion drilling is dark to embedding rock 1m the block stamp of percussive drill is proposed, the rock particles that now bottom of interior casing 3 has one deck to smash, prop up the interior casing 3 of pad and form hole, casing 3 in river flows into along interior casing 3 bottom holes, thereby take grouting for water blocking material shutoff water source.In the present embodiment, adopt the biliquid slurry or the polyurethane injecting paste material shutoff water source that are formed by the ultra-fine high-early (strength) cement of HSC and water glass.The main component of polyurethane injecting paste material is polyurethane, produces chemical reaction after chance water, and produces a large amount of gas, very fast and stone fragment generates artificial stone, and can not be diluted by water, stops current, water plugging effect is fabulous, and consolidation strength is high, and makes interior casing 3 and the embedding rock is fixed is integrated.During actual injection grouting for water blocking material, the conduit of grouting is inserted to the bottom of casing 3 in boring, get final product at the bottom of with small-sized grouting pump, the grouting for water blocking material being injected to hole, injecting height is about 25cm, extract in time conduit after slip casting completes, continue percussion drilling to lower floor's solution cavity after solidifying.

Carry out in step 3 in the drilling construction process, after the block stamp of described percussive drill sinks to and creeps into position, while connecting current the holed side of the wire rope deflection of block stamp, illustrate that bore position herein is oblique rock.

Carry out in step 3 in the drilling construction process, when drilling construction is carried out in oblique petrographic province territory, the block stamp of described percussive drill need be replaced by reinforced block stamp as shown in Figure 3 and Figure 4.As shown in Figure 3 and Figure 4, when drilling construction is carried out in oblique petrographic province territory, reinforced block stamp used comprises and being vertically to the middle part column 1-1 laid and a plurality of tooth that rushes along the circumferential direction evenly be laid on the column 1-1 lateral wall of middle part, described middle part column 1-1 is the cylindrical, massive steel column, and the diameter of described middle part column 1-1 is 500mm～800mm.A plurality of described structure and sizes of rushing tooth are all identical, and a plurality of described teeth that rush are the rail 1-2 that top is weldingly fixed on column 1-1 middle and upper part, middle part, and the laying of a plurality of described rail 1-2 is highly all identical.Between a plurality of described rail 1-2 and middle part column 1-1, all by gusset 1-3, be fastenedly connected.The bottom height of described middle part column 1-1 is not less than the bottom height of a plurality of described rail 1-2, and a plurality of described rail 1-2 all are and are tilted to laying, and the angle between a plurality of described rail 1-2 and middle part column 1-1 is 15 °～20 °.The vertical height H of described rail 1-2 is 1500mm～2000mm.

In the present embodiment, a plurality of described rail 1-2 all are weldingly fixed on the lateral wall of middle part column 1-1 by gusset 1-3, and the quantity of described gusset 1-3 is identical with the quantity of rail 1-2, and a plurality of described gusset 1-3 along the circumferential direction evenly lay.

Actually add man-hour, the quantity of a plurality of described rail 1-2 is 4～8.In the present embodiment, the quantity of a plurality of described rail 1-2 is 6.Specifically add man-hour, can be according to actual needs, the quantity of a plurality of described rail 1-2 is adjusted accordingly.

In the present embodiment, described middle part column 1-1 is the 45# round steel, and described gusset 1-3 is flat plate.The diameter of described middle part column 1-1 is 600mm.The specification of a plurality of described rail 1-2 is 50kg/m.

Actually add man-hour, the thickness of slab of described gusset 1-3 is 15mm～25mm.The vertical spacing on column 1-1 top, described middle part and rail 1-2 top is 450mm～550mm, and the vertical spacing of column 1-1 bottom, described middle part and rail 1-2 bottom is 220mm～250mm.In the present embodiment, the thickness of slab of described gusset 1-3 is 20mm, and the vertical spacing on column 1-1 top, described middle part and rail 1-2 top is 500mm, and the vertical spacing of column 1-1 bottom, described middle part and rail 1-2 bottom is 240mm.The vertical height H of described rail 1-2 is 1740mm.

Actually add man-hour, can be according to specific needs, the vertical spacing on thickness of slab, column 1-1 top, middle part and the rail 1-2 top of the specification of the material of middle part column 1-1 and diameter, the vertical height H of described rail 1-2, a plurality of described rail 1-2, gusset 1-3 and the vertical spacing of column 1-1 bottom, middle part and rail 1-2 bottom are adjusted accordingly.

In drilled pile drilling construction process, when employing reinforced block stamp is as shown in Figure 3 and Figure 4 processed oblique rock, because its crown is sharp, intensity is high, so result of use is good, while in creeping into, running into oblique rock, adopt with slabstone and clay that tiltedly the rock rock mass strength is identical and carry out backfill, the backfill height is 2m above oblique scar, then hangs down and ram close hitting by oblique rock with this block stamp, once rectify a deviation not all right, repeatedly fill out hit by.If the slabstone that on-the-spot nothing is identical with rock mass strength, can adopt C30 or C40 concreting to the above 1m of oblique scar left and right, after 24h hour, intensity reaches the 2.5MPa requirement, can impact via hole.

In step 3, carry out in the drilling construction process, when the block stamp of described percussive drill passes through because of described need the reason that a solution cavity cap rock layer part is breakdown and another part rock stratum is not breakdown, while tilting to snap in breakdown solution cavity, observe the swing situation of percussive drill wire rope, when wire rope is partial to a side of the boring that drills through, block stamp is blocked, and illustrates that it is consistent with the position of departing from the drill center axis of wire rope that solution cavity punctures part, and not breakdown part is reverse the wire rope offset direction.Now, need to adopt loosening blasting formula bit freezing treating apparatus as shown in Figure 5 to process bit freezing.As shown in Figure 5, described loosening blasting formula bit freezing treating apparatus comprises transfers to the interior bit freezing position of boring from top to bottom and quilt is blocked to drill hammer 2-3 and carry out loosening demolition set, described drill hammer 2-3 is for by wire rope lifting and impact the block stamp entered after solution cavity in the cap rock layer that is stuck in solution cavity, and described wire rope is stretching to be retrodeviated to the left side of boring.Described demolition set comprise dynamite container 2-1 and dynamite container 2-1 is vertical under put into and transfer rope 2-2 between the cap rock layer of block stamp and solution cavity, described dynamite container 2-1 be suspended in transfer rope 2-2 under, described dynamite container 2-1 is fixed on the bottom of transferring rope 2-2, described dynamite container 2-1 and transfer the right side that rope 2-2 all is positioned at boring.Described dynamite container 2-1 comprises that inside is equipped with the paper web of explosive and priming device and is fixed on the described paper web outside or is contained in the balancing weight in described paper web, the sealing drum of described paper web for being sealed by sealant tape.

In the present embodiment, described balancing weight is the soil block that is contained in described paper web inside bottom.

During practice of construction, described balancing weight also can adopt the counter weight construction of other type.

In the present embodiment, described priming device is electric cap, and described electric cap joins by wire and detonating power supply, and the sidewall of described paper web or top have the through wires hole passed for described wire.

In the present embodiment, described paper web is cylindrical.Described dynamite container 2-1 colligation is fixed on the bottom of transferring rope 2-2.

During realtime construction, by transferring rope 2-2 by dynamite container 2-1 and sending on part rock not breakdown in boring and put upside down, then strain the wire rope of block stamp, by electric cap, make explosive initiation produce the horizontal thrust of shock wave afterwards, drill hammer 2-3 is moved or not breakdown rock is shaken, drill hammer 2-3 original position is proposed.Explosive payload in described dynamite container 2-1 is 0.8kg～1kg, and treatment effect is fine.

The above; it is only preferred embodiment of the present invention; not the present invention is imposed any restrictions, every any simple modification of above embodiment being done according to the technology of the present invention essence, change and equivalent structure change, and all still belong in the protection domain of technical solution of the present invention.

Claims (10)

1. a bead string type karst area Construction method of bored pile, a underground river solution cavity is passed through in institute's construction drill stake from top to bottom, it is characterized in that the method comprises the following steps:

Step 1, measurement setting-out: setting-out is measured in the stake position to the construction drill stake of current institute;

Step 2, transfer and fixing steel casing: according to the measurement unwrapping wire result in step 1, transfer steel casing (2) and transferred steel casing (2) is fixed; The length of described steel casing (2) is greater than the depth of water of current institute's construction drill stake present position;

Step 3, creep into: adopt percussive drill and crept into from top to bottom by the steel casing (2) of transferring in step 2, until creep into to projected depth, and adopt mud off in drilling process;

In drilling process, when creeping into to described underground river solution cavity from top to bottom, first described underground river solution cavity is processed, adopted again afterwards described percussive drill to continue to creep into downwards; When described underground river solution cavity is processed, process is as follows:

Step 301, interior casing installing hole drill through: adopt described percussive drill to drill through the installing hole of installing for interior casing (3) on the riverbed of underground river (1);

Transferring steel casing (2) in step 2 is outer casing, and the internal diameter of described interior casing (3) is greater than the stake footpath of current first drilled pile of constructing and the internal diameter that its external diameter is less than described outer casing;

Step 302, interior casing are transferred: transferred by the internal casing of described outer casing (3), and interior casing (3) bottom is arranged in the installing hole that step 301 drills through;

Step 303, continue to creep into: after interior casing (3) is transferred and put in place, then adopt described percussive drill to continue to creep into 0.8m～1.2m downwards, afterwards described percussive drill is proposed from interior casing (3); Now, the bed course that one deck is comprised of the rock particles after being smashed by described percussive drill is left in described interior casing (3) bottom;

Step 304, water source shutoff: internally grouting for water blocking is carried out in casing (3) bottom, and makes on the rock stratum of bottom, interior casing (3) fastening embedding underground river, bottom (1).

2. according to a kind of bead string type karst area Construction method of bored pile claimed in claim 1, it is characterized in that: the institute's construction drill stake from top to bottom quantity of the solution cavity that passes through is two, and two described solution cavities comprise that a described underground river solution cavity and one are positioned at the lower solution cavity that solution cavity below, described underground river and inside do not have underground river (1); In step 3, in drilling process, when creeping into to described lower solution cavity from top to bottom, first adopt NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, adopt again afterwards described percussive drill to continue to creep into downwards.

3. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: the hole depth of installing hole described in step 301 is the 1m left and right; In described in step 302, casing (3) is formed by a plurality of interior casing section assemblings, between neighbouring two described interior casing sections, with welding manner, is fixed connection; Internally casing (3), while being transferred, adopts the mode that a plurality of described interior casing sections are welded to spreading section by section to be transferred.

4. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: in step 3 in the drilling construction process, when the block stamp of described percussive drill passes through because of need that solution cavity cap rock layer breakdown another part of part rock stratum is not breakdown to be tilted to snap in breakdown solution cavity, adopt loosening blasting formula bit freezing treating apparatus processing bit freezing; Described loosening blasting formula bit freezing treating apparatus comprises from top to bottom transfers to the interior bit freezing position of boring and to by card drill hammer (2-3), being carried out loosening demolition set, described drill hammer (2-3) is for by wire rope lifting and impact the block stamp entered after solution cavity in the cap rock layer that is stuck in solution cavity, and described wire rope is stretching to be retrodeviated to the left side of boring; Described demolition set comprise dynamite container (2-1) and dynamite container (2-1) is vertical under put into and transfer rope (2-2) between the cap rock layer of block stamp and solution cavity, described dynamite container (2-1) be suspended in transfer rope (2-2) under, described dynamite container (2-1) is fixed on the bottom of transferring rope (2-2), described dynamite container (2-1) and transfer the right side that rope (2-2) all is positioned at boring; Described dynamite container (2-1) comprises that inside is equipped with the paper web of explosive and priming device and is fixed on the described paper web outside or is contained in the balancing weight in described paper web, the sealing drum of described paper web for being sealed by sealant tape.

5. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: in step 301, carry out before interior casing installing hole drills through, first to whether the riverbed of underground river (1) is smooth, being soundd out; When reality is soundd out whether the riverbed of underground river (1) is smooth, the block stamp of described percussive drill is sunk to the lower solution cavity of current state bottom, when the wire rope that connects block stamp swings serious, illustrate on the riverbed of underground river (1) only pillar or wolf's fang rock are arranged, now need first the only pillar on riverbed or wolf's fang rock to be removed; Otherwise, when the wire rope that connects block stamp slightly swings, illustrate that the riverbed on underground river (1) is smooth; After in described in step 302, casing (3) is transferred and put in place, the top height of described interior casing (3) is not less than the top height of described outer casing, and described percussive drill is positioned at the inside bottom of casing (3); Described interior casing (3) is coaxial laying with described outer casing.

6. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: when in step 304, internally grouting for water blocking is carried out in casing (3) bottom, the grouting for water blocking material adopted is polyurethane injecting paste material or cement-silicate biliquid slurry; When internally grouting for water blocking is carried out in casing (3) bottom, first Grouting Pipe is inserted into to interior casing (3) bottom from top to bottom, adopts afterwards grouting pump and by described Grouting Pipe, described grouting for water blocking material pump is delivered to interior casing (3) bottom.

7. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: in step 3, in drilling process, when oblique rock is carried out to drilling construction, the block stamp of described percussive drill is replaced by reinforced block stamp; Described reinforced block stamp comprises and being vertically to the middle part column (1-1) of laying and a plurality of tooth that rushes along the circumferential direction evenly be laid on column (1-1) lateral wall of middle part, described middle part column (1-1) is the cylindrical, massive steel column, and the diameter of described middle part column (1-1) is 500mm～800mm; A plurality of described structure and sizes of rushing tooth are all identical, and a plurality of described teeth that rush are the rail (1-2) that top is weldingly fixed on column (1-1) middle and upper part, middle part, and the laying of a plurality of described rail (1-2) is highly all identical; Between a plurality of described rail (1-2) and middle part column (1-1), all by gusset (1-3), be fastenedly connected; The bottom height of described middle part column (1-1) is not less than the bottom height of a plurality of described rail (1-2), a plurality of described rail (1-2) all are and are tilted to laying, and the angle between a plurality of described rail (1-2) and middle part column (1-1) is 15 °～20 °; The vertical height H of described rail (1-2) is 1500mm～2000mm.

8. according to a kind of bead string type karst area Construction method of bored pile claimed in claim 2, it is characterized in that: adopt described percussive drill to carry out from top to bottom in drilling process, when creeping into to distance described underground river solution cavity or 1m left and right, described lower solution cavity top, reduce immediately the impact stroke of described percussive drill, with short stroke, fast frequency mode, puncture described underground river solution cavity or described lower solution cavity.

9. according to the described a kind of bead string type karst area Construction method of bored pile of claim 1 or 2, it is characterized in that: in step 3, adopt described percussive drill to carry out from top to bottom in drilling process, the proportion of mud that mud off adopts is 1.2～1.5, viscosity is 22s～30s, sand factor≤4%, pH value are 8～10 and colloidity >=95%;

Creep into to projected depth, also need institute's moulding boring is carried out to hole clearly; Actual while carrying out clearly hole, first the block stamp of described percussive drill is increased to left back apart from 20cm at the bottom of institute's moulding drilling hole, at the bottom of pump line being inserted into to institute's moulding drilling hole again, carry out anti-circulation cleaning hole by described pump line afterwards, until in institute's moulding drilling hole, mud density is less than 1.1g/cm ³.

10. according to a kind of bead string type karst area Construction method of bored pile claimed in claim 2, it is characterized in that: while adopting NE BY ENERGY TRANSFER METHOD to be processed described lower solution cavity, by the interior throwing filling mixture of boring lower solution cavity is carried out to backfill; Described lower solution cavity be hole higher primary school in the small-sized solution cavity of 2m, hole high for the medium-sized solution cavity of 2m～5m or hole tall and big in the large-scale solution cavity of 5m;

Instantly the hole higher primary school of solution cavity is when 2m, and the filling mixture of institute's throwing is the first filling mixture be comprised of slabstone and ball clay; In described the first filling mixture the mass ratio of slabstone and ball clay be (0.8～1.2) ︰ 1, in described the first filling mixture, the particle diameter of slabstone is 10cm～15cm;

Instantly the hole of solution cavity is high while for 2m～5m and inside, having stream to mould the shape filler, by throwing the second filling mixture in institute's boring in step 3, lower solution cavity is carried out to back-filling in layers and also tamps; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the second filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the second filling mixture; Described the second filling mixture is mixed by slabstone, rubble and ball clay, and in described the second filling mixture, the mass ratio of slabstone, rubble and ball clay is (1.8～2.2) ︰ (0.8～1.2) ︰ 2; In described the second filling mixture, the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is below 7cm;

When solution cavity is the high 2m～5m in hole and inner non-filler empty instantly, in boring the filling concrete lower solution cavity is carried out to backfill;

Instantly the hole of solution cavity is tall and big when moulding shape and/or stream in 5m and inside and moulding the shape filler, by boring throwing the 3rd filling mixture lower solution cavity is carried out to back-filling in layers compacting; Each raising 1.5m～2.5m, before each raising first to injected water cement mortar or the two slurries of cement-silicate in described boring, again to described the 3rd filling mixture of throwing in described boring, after each raising, all adopt described percussive drill repeated stock to be tamped, and make injected cement mortar or the two slurries of cement-silicate enter in institute's throwing the 3rd filling mixture; Described the 3rd filling mixture is mixed by piece stone, ball clay, slabstone and rubble or is mixed by piece stone, slabstone, rubble and packed clay, in described the 3rd filling mixture, the mass ratio of piece stone, ball clay, slabstone and rubble is (1.8～2.2) ︰ (1.8～2.2) ︰ (0.8～1.2) ︰ 1, and in described the 3rd filling mixture, the mass ratio of piece stone, slabstone, rubble and packed clay is (1.8～2.2) ︰ (0.8～1.2) ︰ (0.8～1.2) ︰ 1; In described the 3rd fill concrete, the diameter of piece stone is the 40cm left and right, and the particle diameter of slabstone is 15cm～25cm, and the particle diameter of rubble is the 5cm left and right.

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