CN110593254A - Construction method of cast-in-situ bored pile in stratum with karst cave in joint zone - Google Patents
Construction method of cast-in-situ bored pile in stratum with karst cave in joint zone Download PDFInfo
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- CN110593254A CN110593254A CN201910848949.XA CN201910848949A CN110593254A CN 110593254 A CN110593254 A CN 110593254A CN 201910848949 A CN201910848949 A CN 201910848949A CN 110593254 A CN110593254 A CN 110593254A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/06—Placing concrete under water
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
Abstract
A construction method of a cast-in-situ bored pile in a stratum of a joint zone with a karst cave comprises the following steps: leveling the field; carrying out secondary hole probing on the joint zone and the soil dissolving hole; processing a joint zone; treating the soil dissolving holes; building a running bearing layer of cast-in-place pile drilling operation equipment; measuring the center point of the pile position of lofting and burying the ultra-long pile casing; placing the rotary drilling rig in place, and starting drilling operation; cleaning holes for the first time; manufacturing and hoisting a reinforcement cage; installing a guide pipe; secondary hole cleaning; and (5) pouring underwater concrete. According to the invention, by carrying out secondary hole probing and treatment on the joint zone and the soil dissolving hole on the independent pile foundation in the foundation pit in advance, the bed rock fracture channel can be effectively and comprehensively blocked, the groundwater loss is reduced, and the drilling and underwater concrete pouring environments are improved.
Description
Technical Field
The invention relates to the technical field of engineering pile foundation construction, in particular to a method for constructing a cast-in-situ bored pile in a stratum of a joint zone with a karst cave.
Background
The hole forming method commonly adopted by the cast-in-situ bored pile at present is rotary drilling hole forming, the rotary drilling hole forming cast-in-situ pile is suitable for cohesive soil, silt, sandy soil, filling soil, gravel soil and weathered rock stratum, the application effect is obvious, and the construction method is relatively mature.
Under the complex geological conditions of existing joint zone development areas and soil dissolving holes, when the cast-in-place bored pile is constructed, the joint zone water system is communicated, the conditions of fracture water communication and groundwater loss are easy to occur, so that great influence is brought to the pore-forming quality of the cast-in-place pile, the quality of a mud retaining wall in the drilling process can be influenced by the water leakage at the bottom of a hole, when the water inflow is large, the pouring of underwater concrete is directly influenced, and serious quality defects are generated to the quality of the concrete formed into the pile.
Therefore, it is important to ensure the quality of the bored holes of the cast-in-place piles at the pile sites by how to deal with the water through-penetration of the joint zone. In view of construction technology, the existing concrete cast-in-place pile construction method is difficult to apply, and the exploration of a cast-in-place pile construction method in a stratum with a karst cave in a joint zone is urgent.
Disclosure of Invention
The invention aims to solve the technical problems and provides a construction method of a cast-in-situ bored pile in a karst cave clamped joint zone stratum, which can be suitable for the construction of the cast-in-situ bored pile in the karst cave clamped joint zone stratum, can effectively and comprehensively block a bedrock fracture channel, reduce the loss of underground water and improve the drilling and underwater concrete pouring environments.
In order to realize the purpose of the invention, the adopted technical scheme is to provide a cast-in-situ bored pile construction method in a stratum of a joint zone with a karst cave, which comprises the following steps:
(1) leveling the field: mechanically and manually flattening the field of the working surface to finish the preparation of site construction;
(2) carrying out secondary hole probing on the joint zone and the soil dissolving hole: carrying out secondary hole probing on the periphery of the independent pile foundation in the foundation pit according to quincunx hole distribution, and determining index parameters of pile drilling and final hole;
(3) processing the joint zone: drilling holes in the joint zone range on two sides of the open cut station and the co-constructed piles on the joint zone, and then grouting two sides of the foundation pit, wherein firstly, cement paste is adopted for grouting, then, double-liquid slurry grouting is adopted according to the grout outflow amount of the co-constructed pile grouting holes in the foundation pit to cut off the water system in the joint zones on two sides of the foundation pit, so that the water system in the foundation pit is closed, and finally, grouting treatment is carried out in the foundation pit by adopting sleeve valve pipes;
(4) and (3) soil dissolving hole treatment: for unfilled karst (soil) holes, adopting cement mortar or cement paste for grouting and filling; for filling the soil-dissolving hole, the filler is checked by adopting a standard penetration, the treatment is not carried out when the standard penetration number is more than 10 hits, when the standard penetration number is less than or equal to 10 hits, the periphery of the soil-dissolving hole is sealed by adopting double-slurry grouting, and the interior of the soil-dissolving hole is grouted by adopting cement slurry;
(5) building bored concrete pile drilling operation equipment and traveling bearing layer: the soft soil stratum on the surface of the stratum is filled and replaced through a filling material, and the filling material is a material with better bearing capacity;
(6) measuring the central point of the pile position of lofting and burying an ultra-long pile casing: determining the position of a cast-in-place pile, radially leading out cross lines to the periphery to the outer diameter position of the overlong pile casing by taking the central shaft of the position of the cast-in-place pile as a cross point according to the diameter of the pile casing, embedding the overlong pile casing according to the outer diameter position, wherein the embedding of the overlong pile casing needs to penetrate through a silt layer and a sand layer;
(7) placing a rotary drilling rig in place, and starting drilling operation: driving the rotary drilling rig to the determined position of the cast-in-place pile and starting drilling;
(8) cleaning holes for the first time: when the hole depth reaches the design requirement, stopping drilling, leaving the drilling bucket in place, mechanically rotating for several circles, filling the hole bottom soil into the drilling bucket as much as possible, then pulling out the drill, preventing the drill bit from scraping the hole wall during pulling out the drill, filling slurry into the hole, stabilizing the height of a water head in the hole, and cleaning the hole bottom soil after pulling out the drill;
(9) manufacturing and hoisting a steel reinforcement cage: the steel reinforcement cage is manufactured in sections, the steel reinforcement cage is lengthened and mechanically connected, the steel reinforcement cage is hoisted and lowered into a hole site by a two-point hoisting method, and the steel reinforcement cage is strictly prevented from swinging and colliding with the hole wall during lowering;
(10) installing a guide pipe: after the steel reinforcement cage is hoisted, the guide pipes for concrete pouring are installed through a crane, the guide pipes are firmly connected through screw threads, and a sealing ring is additionally arranged; when the guide pipe is installed, the position of a lifting hook of the crane is adjusted, the guide pipe is placed in the middle of a hole position as much as possible, and the guide pipe is slowly placed down to avoid colliding a reinforcement cage;
(11) secondary hole cleaning: after the guide pipe is installed, secondary hole cleaning is immediately carried out, the hole cleaning is carried out in a reverse circulation mode, and the original water head height in the hole must be kept all the time in the hole cleaning process to prevent hole collapse;
(12) pouring underwater concrete: and (4) pouring the underwater concrete within 30 minutes after the secondary hole cleaning is qualified, wherein the concrete pouring is continuously carried out until the concrete pouring is finished.
As a further improvement of the method, in the step (2), secondary hole probing is carried out within 2m of the periphery of the independent pile foundation in the foundation pit according to quincunx hole distribution with the distance not more than 2m, wherein if the hole is in a stable water-resisting layer or a complete rock body, the drilling depth is required to be drilled to a final hole of 3m below the bottom of the pile foundation; if meeting the karst cave, drilling through the karst cave until a complete rock mass is drilled and the final hole with the thickness not less than 2m is drilled; if special geology such as a corrosion groove and a broken zone is encountered, the final hole condition is determined after comprehensive judgment according to the buried depth and the underground water property.
As a further improvement of the present invention, in step (3), the relevant parameters are as follows:
firstly, the initial grouting pressure is 0.2-0.3 MPa, and the final grouting pressure is 0.8-1 MPa;
secondly, adopting 42.5-grade ordinary silica cement slurry as a grouting material, wherein the water-cement ratio W is that MC is (0.6-0.8) and 1 is;
thirdly, sealing water and plugging after grouting are needed to be done on the grouting pipe;
and fourthly, the sleeve valve tube is an A48 sleeve valve tube.
As a further improvement of the invention, in the step (4), during grouting, the grouting pipe enters a position which is not less than 0.5m below the bottom of the solution (soil) hole; the grouting parameters were as follows:
firstly, grouting pressure is 0-1.0 MPa; the grouting pressure is gradually increased to reach the final grouting pressure and the grouting is continued for more than 10 min;
secondly, 42.5-grade ordinary portland cement is adopted as cement; the water-cement ratio is 1.0-1.5;
thirdly, grouting speed: 30-70L/min;
fourthly, grouting while filling and grouting, and checking the scale of a solution (soil) hole and the state after treatment; and (4) primarily estimating the scale of the solution (soil) hole according to the grouting amount and the hole diameter of the solution (soil) hole detected by the grouting hole, and then arranging inspection holes to the periphery. The inspection hole needs to be inspected except for the extension condition of the karst cave and the grouting filling condition, and the inspection hole needs to be used for continuous grouting when the grouting is not full.
As a further improvement of the invention, in the step (5), the replacement filling thickness is 1-1.5 m, the filling is brick slag or concrete slag, and a steel plate with the thickness of at least 3mm is prepared for use in the drilling operation process and the emergency of equipment walking.
As a further improvement of the invention, in the step (7), when the drilling operation is carried out on the soft soil layer, the drilling tool adopts a single-side soil feeding bucket tooth sand fishing drill bit to drill the hole; when drilling in a rock-sandwiched stratum, the drilling tool adopts a hard rock sand dredging drill bit with double-side earth feeding cutting teeth, and the perpendicularity of formed holes is ensured by lightly pressing a slow drill; when drilling in a hard rock stratum, the drilling tool firstly adopts a short spiral drill head to crush the hard rock, then adopts a barrel type drill head to cut and repair the hole wall, and finally adopts a sand dredging drill head to take out the rest rock debris; when the hole drilling operation is carried out on the silicified joint zone of which the average uniaxial compressive strength of the rock in a natural state is 64.3MPa, the drilling tool adopts a roller cone core barrel drill.
As a further improvement of the invention, in the step (10), before the installation of the conduit, a water sealing test is carried out, and the test pressure is not lower than 0.3 MPa; the distance between the position of the pipe orifice of the guide pipe and the bottom of the hole is kept between 30 and 50 cm.
As a further improvement of the method, in the step (12), the pipe is frequently measured and disassembled during the pouring process, the buried depth of the guide pipe is always kept to be about 2.0-6.0 m, and meanwhile, whether abnormal conditions exist in the hole is judged according to the measurement result, the guide pipe is strictly prevented from being lifted out of the concrete surface, and the broken pile is formed.
As a further improvement of the invention, the method also comprises the step (13) of recycling the steel reinforcement cage hanging bars: after concrete pouring is finished, before the pile casing is pulled out, the hanging ribs of the upper empty pile part of the cast-in-place pile concrete are recycled through the detachable device of the hanging ribs.
As a further improvement of the invention, the detachable device comprises a steel reinforcement cage, a hanging rib, a guide ring, a movable rope, a drawing ring, an elastic anti-falling buckle and a pulley. The welding has rings on the steel reinforcement cage, the top of lifting muscle is equipped with lifting muscle rings, the end is equipped with the lifting hook that is used for the half-opening setting of being connected with steel reinforcement cage rings, the hinged end elasticity of elasticity anti-drop buckle articulates on the lifting hook, the activity end top is pressed the half-opening of hook head department movable closed lifting hook at the lifting hook, the lifting hook sets up the pulley for half-opening opposite side, the guide ring is evenly arranged along the length direction of lifting muscle according to certain distance, draw 5 settings on the top of activity rope, the tail end of activity rope passes the guide ring in proper order, and be connected with the expansion end of elasticity anti-drop buckle behind the pulley, the activity rope is the state of tightening, can make the half-opening of elasticity anti-drop buckle in order to open the lifting hook toward the inboard rotation of lifting.
The invention has the beneficial effects that:
one, special function
According to the invention, by carrying out secondary hole probing and treatment on the joint zone and the soil dissolving hole on the independent pile foundation in the foundation pit in advance, the bed rock fracture channel can be effectively and comprehensively blocked, the groundwater loss is reduced, and the drilling and underwater concrete pouring environments are improved.
High efficiency
By using the method for construction, bed rock fracture water inflow is effectively isolated, the occurrence of water burst at the bottom of the pile foundation hole is prevented, the labor cost for cleaning collapsed holes and slag falling and even re-drilling serious collapsed holes due to the adverse effect of a large amount of water burst at the bottom of the hole on the mud retaining wall is reduced, stable drilling is realized, and a large number of construction periods are saved for pile foundation construction of the bearing platform.
Thirdly, the construction quality is guaranteed
By adopting the construction method, measures are taken to prevent the crack water from communicating before the pile foundation pore-forming operation, the water stopping effect of slurry filling the crack channel is fully exerted, the communication of underground water is reduced, and the drilling operation and the underwater concrete pouring environment quality are effectively ensured. The process of the operation of the ultra-long pile casing in the miscellaneous fill and the sludge layer effectively prevents the hole collapse caused by the influence of mechanical operation and the quality of the slurry retaining wall, also effectively prevents the operation under the condition of a double-pile bearing platform and the condition that the hole jumping is generated at the empty pile backfilling part at the upper parts of two adjacent cast-in-place piles, and effectively ensures the hole forming quality of the cast-in-place piles.
Four, economy
The ultra-long pile casing ensures the hole forming quality, avoids local hole collapse caused by geological influence, and avoids overlong delay of the hole forming time of the whole pile foundation, so that the effective pile hole part is also reamed and collapsed, and the concrete is over-square; advanced treatment of the joint zone and the soil-dissolving hole and plugging of fracture water effectively accelerate the hole forming speed of the cast-in-place pile, and increase of corresponding engineering cost caused by treatment in the hole forming process under many emergency conditions is avoided; meanwhile, the underwater concrete pouring quality is ensured, and the quality defect of pile body concrete caused by the influence of underground water is avoided. And a large amount of labor cost and construction period cost are saved.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a schematic view of a detachable device according to the present invention;
description of the labeling: the steel bar pulling device comprises a steel bar cage 1, a lifting ring 11, a lifting rib 2, a lifting hook 21, a guide ring 3, a movable rope 4, a pulling ring 5, an elastic anti-falling buckle 6 and a pulley 7.
Detailed Description
The invention is further described with reference to the following specific embodiments and the accompanying drawings.
Carrying out pile foundation construction on a combined construction part of a subway station and a certain viaduct on a certain rail traffic engineering project of Guangdong province, Guangzhou city, wherein the station structure is an underground two-layer cast-in-place concrete structure, a radioactive ray viaduct pier passes through a column field of the subway station to a pile foundation of a bottom bearing platform, and 32 piers in total in the main body range of the station need to reserve connection conditions by the station column and bear bridge load; the design pile foundation of the bearing platform is 60, the design pile length is 15-51.5 m, the design hole depth is 35.16-72.04 m, the pile foundation diameter is large (1.8m), the hole depth is as deep as 72.04m, and the underwater concrete volume is large (the maximum volume of a single pile is 133.53 m)3) The distance between the piles of the double-pile bearing platform is short (1.8m), so that partial hole collapse and hole channeling of hollow piles of a sludge layer are easily caused, the pile end bearing layer is mainly made of slightly weathered siltstone and has deep soft soil relatively developed and a relatively thick miscellaneous fill layer locally existing, and the weak stratum is<2-1A>The soft flow plastic state of the sludge layer is that the minimum standard penetration value is N which is 1-3 hits, the joint zone stretches across the foundation pit of the station in a strip shape, the joint zone is constructed in local development, the crack water is developed abundantly, and the water system is through; a small part of weak development karst phenomenon covers the middle slightly weathered clastic rock, an interlayer with uneven hardness and uneven rock surface burial depth; the individual combined pile position penetrates through a soil dissolving hole and a joint zone, and the technical challenges such as selection of hole forming equipment, hole forming drilling control, hole bottom slag removal control and the like are developed, so that the pile forming construction difficulty is high. In order to smoothly complete the construction of the pile foundation, the project adopts the construction method of the cast-in-situ bored pile in the stratum of the joint zone with the karst cave。
As shown in fig. 1, a method for constructing a bored pile in a stratum of a joint zone with a karst cave comprises the following steps:
(1) leveling the field: and (3) leveling the operation surface field mechanically and manually, preparing water and electricity for field construction, and ensuring that the requirements required by underground water system through processing the joint zone and grouting operation of a soil dissolving hole are met before cast-in-place pile construction.
(2) Carrying out secondary hole probing on the joint zone and the soil dissolving hole: before the drilling construction of the pile foundation, according to the existing design details and supplementary geotechnical engineering investigation report, carrying out secondary hole probing within the range of 2m around the independent pile foundation in the foundation pit according to quincunx hole distribution with the interval not more than 2m, and determining the index parameters of the pile drilling hole and the final hole; if the hole is in a stable water-resisting layer or a complete rock body, the drilling depth is required to be 3m of a final hole below the bottom of the pile foundation; if meeting the karst cave, drilling through the karst cave until a complete rock mass is drilled and the final hole with the thickness not less than 2m is drilled; if special geology such as a corrosion groove and a broken zone is encountered, the final hole condition is determined after comprehensive judgment according to the buried depth and the underground water property.
(3) The joint zone is treated to prevent the crack water system from penetrating and influencing the quality of pore-forming and concrete pouring: before treating joint zones in a foundation pit by pre-grouting, drilling holes in joint zone ranges on two sides of an open-cut station and on a co-constructed pile on the joint zones, then grouting on two sides of the foundation pit by adopting a plurality of double-liquid grouting machines, wherein grouting is firstly carried out by adopting cement paste, then double-liquid grouting is adopted according to the grout outflow amount of a co-constructed pile grouting hole in the foundation pit to cut off a water system in the joint zones on two sides of the foundation pit, the water system in the foundation pit is closed, and finally grouting treatment is carried out in the foundation pit by adopting a sleeve valve pipe, wherein the relevant parameters are as follows:
firstly, the initial grouting pressure is 0.2-0.3 MPa, and the final grouting pressure is 0.8-1 MPa;
secondly, adopting 42.5-grade ordinary silica cement slurry as a grouting material, wherein the water-cement ratio W is that MC is (0.6-0.8) and 1 is;
thirdly, sealing water and plugging after grouting are needed to be done on the grouting pipe;
and fourthly, the sleeve valve tube is an A48 sleeve valve tube.
(4) The soil dissolving hole is processed, accidents such as buried drilling, slurry leakage and the like generated in the pore-forming process are prevented from influencing pore-forming speed and quality: for unfilled soil-dissolved holes, adopting cement mortar or cement paste to carry out grouting filling, wherein larger soil-dissolved holes can be filled with cement mortar firstly; and for filling the soil-dissolving hole, the filler is checked by adopting a standard penetration, the treatment is not carried out when the standard penetration number is more than 10 hits, when the standard penetration number is less than or equal to 10 hits, the periphery of the soil-dissolving hole is sealed by adopting double-fluid grouting, and the interior of the soil-dissolving hole is grouted by adopting cement paste. During grouting, the grouting pipe enters a position which is not less than 0.5m below the bottom of the soil dissolving hole. The grouting parameters were as follows:
firstly, grouting pressure is 0-1.0 MPa; the grouting pressure is gradually increased to reach the final grouting pressure and the grouting is continued for more than 10 min;
secondly, 42.5-grade ordinary portland cement is adopted as cement; the water-cement ratio is 1.0-1.5;
thirdly, grouting speed: 30-70L/min;
fourthly, grouting while filling and grouting, and checking the scale of a solution (soil) hole and the state after treatment; and (4) primarily estimating the scale of the solution (soil) hole according to the grouting amount and the hole diameter of the solution (soil) hole detected by the grouting hole, and then arranging inspection holes to the periphery. The inspection hole needs to be inspected except for the extension condition of the karst cave and the grouting filling condition, and the inspection hole needs to be used for continuous grouting when the grouting is not full.
(5) Building bored concrete pile drilling operation equipment and traveling bearing layer: before the drilling machine is in place, soft soil strata such as miscellaneous filling soil on the surface of the stratum, garbage soil and the like are filled and replaced through filling materials, the filling thickness is 1-1.5 m, the filling materials are materials with good bearing capacity such as brick slag or concrete slag, and meanwhile, steel plates with the thickness of at least 3mm are prepared for use in the drilling operation process and the equipment walking emergency.
(6) According to the design drawing, measuring the center point of a lofting pile position, and embedding an ultra-long pile casing: determining the position of a cast-in-place pile, radially leading out cross lines to the outer diameter position of the overlong pile casing by taking the central shaft of the position of the cast-in-place pile as a cross point according to the diameter of the pile casing, embedding the overlong pile casing according to the outer diameter position, and rechecking whether the position of the cast-in-place pile is consistent with the position on a design drawing after embedding; the embedding of the ultra-long pile casing needs to penetrate through a silt layer and a sand layer, so that the hole collapse in the drilling process can be effectively avoided, and the phenomenon that a backfilled hollow pile part and another drilled pile hole are subjected to hole channeling after the adjacent construction of the double-pile bearing platform is completed can be effectively avoided.
(7) Placing a rotary drilling rig in place, and starting drilling operation: and the rotary drilling rig drives to the determined position of the cast-in-place pile and starts to drill. When drilling is carried out on soft soil layers such as artificial fill layers, sea-land interaction layers, flood, alluvial soil layers, residual soil layers and the like, the drilling tool adopts a single-side soil inlet bucket tooth sand fishing drill bit to drill, and the drilling is stopped when normal operation is carried out until hard rock layers such as moderate weathering or slightly weathering and the like; when drilling in a rock-sandwiched stratum, the drilling tool adopts a hard rock sand dredging drill bit with double-side earth feeding cutting teeth, and the perpendicularity of formed holes is ensured by lightly pressing a slow drill; when drilling in a hard rock stratum, the drilling tool firstly adopts a short spiral drill head to crush the hard rock, then adopts a barrel type drill head to cut and repair the hole wall, and finally adopts a sand dredging drill head to take out the rest rock debris; when the hole drilling operation is carried out on the silicified joint zone of which the average uniaxial compressive strength of the rock in a natural state is 64.3MPa, the drilling tool adopts a roller cone core barrel drill.
(8) Cleaning holes for the first time: when the hole depth reaches the design requirement, stopping drilling, leaving the drilling bucket in place, mechanically rotating for several circles, filling the deficient soil at the bottom of the hole into the drilling bucket as much as possible, and then pulling out the hole. After the hole is drilled, the loose soil at the bottom of the hole still needs to be cleaned, and the sediment at the bottom of the drilled hole is generally cleaned by using a hole cleaning drilling tool.
(9) Manufacturing and hoisting a steel reinforcement cage: in order to facilitate the rotation of the reinforcement cage and avoid the deformation of the reinforcement cage in the hoisting process, the reinforcement cage is manufactured in sections, the lengthening of the reinforcement cage adopts mechanical connection, the reinforcement cage is hoisted and lowered into a hole site by adopting a two-point hoisting method, and the reinforcement cage is strictly prohibited to swing to collide with the hole wall during lowering;
(10) installing a guide pipe: after the reinforcement cage is hoisted, installing guide pipes for concrete pouring by using a crane, adopting phi 250 guide pipes, firmly connecting the guide pipes by using screw threads, and additionally arranging a sealing ring; before the installation of the conduit, a water sealing test is carried out, and the test pressure is not lower than 0.3 Mpa; when the guide pipe is installed, the position of a lifting hook of the crane is adjusted, the guide pipe is placed in the middle of a hole position as much as possible, the guide pipe is slowly placed, the steel bar cage is prevented from being collided, and the guide pipe is strictly prohibited from being violently lifted and violently dropped; the distance between the position of the pipe orifice of the guide pipe and the bottom of the hole is kept between 30 and 50cm, so that the smooth concrete in the pipe is ensured.
(11) Secondary hole cleaning: after the guide pipe is installed, secondary hole cleaning is immediately carried out, the hole cleaning is carried out in a reverse circulation mode, and the original water head height in the hole must be kept all the time in the hole cleaning process to prevent hole collapse;
(12) pouring underwater concrete: and (4) pouring the underwater concrete within 30 minutes after the secondary hole cleaning is qualified, wherein the concrete pouring is continuously carried out until the concrete pouring is finished. The casting process is carried out on duty and measurement is carried out, the pipe is frequently disassembled, the buried depth of the guide pipe is always kept to be about 2.0-6.0 m, whether abnormal conditions exist in the hole is judged according to the measurement result, the guide pipe is strictly forbidden to be lifted out of the concrete surface, and pile breakage is formed.
(13) The recycling of steel reinforcement cage hanging bar reduces economic cost: after concrete pouring is finished, before the pile casing is pulled out, the hanging ribs of the part of the hollow pile above the cast-in-place pile concrete is subjected to super-pouring are recycled through the detachable device of the hanging ribs, and a large amount of material cost and economic cost are saved for engineering.
As shown in fig. 2, the detachable device in step (13) includes a reinforcement cage 1, a hanging bar 2, a guide ring 3, a movable rope 4, a drawing ring 5, an elastic anti-drop buckle 6 and a pulley 7. The welding has rings 11 on steel reinforcement cage 1, the top of lifting muscle 2 is equipped with lifting muscle rings, the end is equipped with the lifting hook 21 that is used for the half-opening setting of being connected with 1 rings 11 of steel reinforcement cage, elasticity anti-drop buckle 6's hinged end elasticity articulates on lifting hook 21, the activity end top is pressed the half-opening of hook 21's gib head department movable closed lifting hook 21, lifting hook 21 sets up pulley 7 for half-open-ended opposite side, guide ring 3 evenly arranges along the length direction of lifting muscle 2 according to certain distance, draw ring 5 and set up the top at activity rope 4, the tail end of activity rope 4 passes guide ring 3 in proper order, and be connected with the expansion end of elasticity anti-drop buckle 6 after passing pulley 7, activity rope 4 is the state of tightening, can make elasticity anti-drop buckle 6 toward the inboard half-opening of lifting hook 21 rotate in order to open lifting hook 21 through pulling activity rope 4. Pulley 7 and guide ring 3 all play limiting displacement to the activity direction of activity rope 4 to guarantee elasticity anti-drop buckle 6's activity direction and operation smoothness nature, and draw ring 5 can be convenient for operate activity rope 4.
The detachable device comprises the following use procedures:
(1) hoisting: firstly, a reinforcement cage 1 is placed down by a hoisting method of two-point hoisting, when the reinforcement cage 1 is placed down to the end part, firstly, the reinforcement cage 1 is stabilized by a support shaft at the top of an orifice of a cast-in-place pile, then, a lifting hook 21 at the lower part of the reinforcement cage is connected with a lifting ring 11 on the end part of the reinforcement cage 1 through a prefabricated lifting rib 2, a lifting machine lifts and straightens the lifting ring at the top end of the upper part of the lifting rib 2, and then, the reinforcement cage 1 is placed down to a designed elevation;
(2) and (4) disassembling and recycling: after pile foundation concrete construction is accomplished, draw ring 5 through the annex on hanging 2 tops of muscle and draw elastic anti-drop buckle 6 to hanging 2 lower part lifting hooks 21 of muscle for lifting hook 21 is in the open mode, then will hang 2 pushes down of muscle, makes lifting hook 21 and rings 11 of 1 tip of steel reinforcement cage be in after the unhook state, and rotatory lifting hook 21 direction prevents that lifting hook 21 and rings 11 from repeatedly dragging, at last toward ground after mentioning recycle. It should be noted that the extraction time of the hanger bar 2 is too early, which may cause the reinforcement cage 1 to sink.
In summary, the present invention has been made in the following description and drawings, and after a plurality of usage tests, the effect of the usage tests proves that the present invention can achieve the expected purpose, and the practical value is needless to say. The above-mentioned embodiments are only for convenience of illustration and not intended to limit the invention in any way, and those skilled in the art will be able to make equivalents of the features of the invention without departing from the technical scope of the invention.
Claims (10)
1. A construction method of a cast-in-situ bored pile in a stratum of a joint zone with a karst cave is characterized by comprising the following steps:
(1) leveling the field: mechanically and manually flattening the field of the working surface to finish the preparation of site construction;
(2) carrying out secondary hole probing on the joint zone and the soil dissolving hole: carrying out secondary hole probing on the periphery of the independent pile foundation in the foundation pit according to quincunx hole distribution, and determining index parameters of pile drilling and final hole;
(3) processing the joint zone: drilling holes in the joint zone range on two sides of the open cut station and the co-constructed piles on the joint zone, and then grouting two sides of the foundation pit, wherein firstly, cement paste is adopted for grouting, then, double-liquid slurry grouting is adopted according to the grout outflow amount of the co-constructed pile grouting holes in the foundation pit to cut off the water system in the joint zones on two sides of the foundation pit, so that the water system in the foundation pit is closed, and finally, grouting treatment is carried out in the foundation pit by adopting sleeve valve pipes;
(4) and (3) soil dissolving hole treatment: for unfilled karst (soil) holes, adopting cement mortar or cement paste for grouting and filling; for filling the soil-dissolving hole, the filler is checked by adopting a standard penetration, the treatment is not carried out when the standard penetration number is more than 10 hits, when the standard penetration number is less than or equal to 10 hits, the periphery of the soil-dissolving hole is sealed by adopting double-slurry grouting, and the interior of the soil-dissolving hole is grouted by adopting cement slurry;
(5) building bored concrete pile drilling operation equipment and traveling bearing layer: the soft soil stratum on the surface of the stratum is filled and replaced through a filling material, and the filling material is a material with better bearing capacity;
(6) measuring the central point of the pile position of lofting and burying an ultra-long pile casing: determining the position of a cast-in-place pile, radially leading out cross lines to the periphery to the outer diameter position of the overlong pile casing by taking the central shaft of the position of the cast-in-place pile as a cross point according to the diameter of the pile casing, embedding the overlong pile casing according to the outer diameter position, wherein the embedding of the overlong pile casing needs to penetrate through a silt layer and a sand layer;
(7) placing a rotary drilling rig in place, and starting drilling operation: driving the rotary drilling rig to the determined position of the cast-in-place pile and starting drilling;
(8) cleaning holes for the first time: when the hole depth reaches the design requirement, stopping drilling, leaving the drilling bucket in place, mechanically rotating for several circles, filling the hole bottom soil into the drilling bucket as much as possible, then pulling out the drill, preventing the drill bit from scraping the hole wall during pulling out the drill, filling slurry into the hole, stabilizing the height of a water head in the hole, and cleaning the hole bottom soil after pulling out the drill;
(9) manufacturing and hoisting a steel reinforcement cage: the steel reinforcement cage is manufactured in sections, the steel reinforcement cage is lengthened and mechanically connected, the steel reinforcement cage is hoisted and lowered into a hole site by a two-point hoisting method, and the steel reinforcement cage is strictly prevented from swinging and colliding with the hole wall during lowering;
(10) installing a guide pipe: after the steel reinforcement cage is hoisted, the guide pipes for concrete pouring are installed through a crane, the guide pipes are firmly connected through screw threads, and a sealing ring is additionally arranged; when the guide pipe is installed, the position of a lifting hook of the crane is adjusted, the guide pipe is placed in the middle of a hole position as much as possible, and the guide pipe is slowly placed down to avoid colliding a reinforcement cage;
(11) secondary hole cleaning: after the guide pipe is installed, secondary hole cleaning is immediately carried out, the hole cleaning is carried out in a reverse circulation mode, and the original water head height in the hole must be kept all the time in the hole cleaning process to prevent hole collapse;
(12) pouring underwater concrete: and (4) pouring the underwater concrete within 30 minutes after the secondary hole cleaning is qualified, wherein the concrete pouring is continuously carried out until the concrete pouring is finished.
2. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (2), secondary hole probing is carried out within 2m of the periphery of the independent pile foundation in the foundation pit according to quincunx hole distribution with the distance not more than 2m, wherein if the hole is in a stable water-resisting layer or a complete rock body, the drilling depth is required to be drilled to a final hole of 3m below the bottom of the pile foundation; if meeting the karst cave, drilling through the karst cave until a complete rock mass is drilled and the final hole with the thickness not less than 2m is drilled; if special geology such as a corrosion groove and a broken zone is encountered, the final hole condition is determined after comprehensive judgment according to the buried depth and the underground water property.
3. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in step (3), the relevant parameters are as follows:
firstly, the initial grouting pressure is 0.2-0.3 MPa, and the final grouting pressure is 0.8-1 MPa;
secondly, adopting 42.5-grade ordinary silica cement slurry as a grouting material, wherein the water-cement ratio W is that MC is (0.6-0.8) and 1 is;
thirdly, sealing water and plugging after grouting are needed to be done on the grouting pipe;
and fourthly, the sleeve valve tube is an A48 sleeve valve tube.
4. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (4), during grouting, the grouting pipe enters a position which is not less than 0.5m below the bottom of the soil dissolving hole; the grouting parameters were as follows:
firstly, grouting pressure is 0-1.0 MPa; the grouting pressure is gradually increased to reach the final grouting pressure and the grouting is continued for more than 10 min;
secondly, 42.5-grade ordinary portland cement is adopted as cement; the water-cement ratio is 1.0-1.5;
thirdly, grouting speed: 30-70L/min;
fourthly, grouting while filling and grouting, and checking the scale of a solution (soil) hole and the state after treatment; and (4) primarily estimating the scale of the solution (soil) hole according to the grouting amount and the hole diameter of the solution (soil) hole detected by the grouting hole, and then arranging inspection holes to the periphery. The inspection hole needs to be inspected except for the extension condition of the karst cave and the grouting filling condition, and the inspection hole needs to be used for continuous grouting when the grouting is not full.
5. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (5), the replacement and filling thickness is 1-1.5 m, the filling is brick slag or concrete slag, and a steel plate with the thickness of at least 3mm is prepared for use in the drilling operation process and the emergency of equipment walking.
6. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (7), when drilling operation is carried out on the soft soil layer, the drilling tool adopts a single-side soil inlet bucket tooth sand fishing drill bit to drill holes; when drilling in a rock-sandwiched stratum, the drilling tool adopts a hard rock sand dredging drill bit with double-side earth feeding cutting teeth, and the perpendicularity of formed holes is ensured by lightly pressing a slow drill; when drilling in a hard rock stratum, the drilling tool firstly adopts a short spiral drill head to crush the hard rock, then adopts a barrel type drill head to cut and repair the hole wall, and finally adopts a sand dredging drill head to take out the rest rock debris; when the hole drilling operation is carried out on the silicified joint zone of which the average uniaxial compressive strength of the rock in a natural state is 64.3MPa, the drilling tool adopts a roller cone core barrel drill.
7. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (10), a water sealing test is carried out before the guide pipe is installed, and the test pressure is not lower than 0.3 Mpa; the distance between the position of the pipe orifice of the guide pipe and the bottom of the hole is kept between 30 and 50 cm.
8. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: in the step (12), the pipe is frequently disassembled on duty during the pouring process, the buried depth of the guide pipe is always kept to be about 2.0-6.0 m, whether abnormal conditions exist in the hole is judged according to the measuring result, the guide pipe is strictly prevented from being lifted out of the concrete surface, and the broken pile is formed.
9. The method for constructing the bored pile in the stratum of the joint zone with the karst cave according to claim 1, wherein: still include step (13) steel reinforcement cage and hang recycle of muscle: after concrete pouring is finished, before the pile casing is pulled out, the hanging ribs of the upper empty pile part of the cast-in-place pile concrete are recycled through the detachable device of the hanging ribs.
10. The method for constructing a bored pile in a stratum of a joint zone with a karst cave according to claim 9, wherein: the detachable device comprises a steel reinforcement cage, a hanging rib, a guide ring, a movable rope, a drawing ring, an elastic anti-falling buckle and a pulley. The welding has rings on the steel reinforcement cage, the top of lifting muscle is equipped with lifting muscle rings, the end is equipped with the lifting hook that is used for the half-opening setting of being connected with steel reinforcement cage rings, the hinged end elasticity of elasticity anti-drop buckle articulates on the lifting hook, the activity end top is pressed the half-opening of hook head department movable closed lifting hook at the lifting hook, the lifting hook sets up the pulley for half-opening opposite side, the guide ring is evenly arranged along the length direction of lifting muscle according to certain distance, draw 5 settings on the top of activity rope, the tail end of activity rope passes the guide ring in proper order, and be connected with the expansion end of elasticity anti-drop buckle behind the pulley, the activity rope is the state of tightening, can make the half-opening of elasticity anti-drop buckle in order to open the lifting hook toward the inboard rotation of lifting.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113404040A (en) * | 2021-07-06 | 2021-09-17 | 中铁二十局集团第六工程有限公司 | Construction method of bored pile foundation |
| CN115110520A (en) * | 2022-04-27 | 2022-09-27 | 中国建筑第七工程局有限公司 | Construction method of bridge pile foundation on highway |
| CN115434304A (en) * | 2022-08-06 | 2022-12-06 | 河南黄河河务局工程建设中心 | Construction method for long auger bored pile super-long reinforcement cage pile-entering hole |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001214438A (en) * | 2000-02-02 | 2001-08-07 | East Japan Railway Co | Method for construction cast-in-place concrete pile, and preload device onto ground under bottom of cast-in- place concrete pile. |
| KR20100072511A (en) * | 2008-12-22 | 2010-07-01 | 재단법인 포항산업과학연구원 | Hollow steel-concrete composite cast-in-situ piles and method of carrying out construction works thereof |
| EP2712964A1 (en) * | 2012-09-26 | 2014-04-02 | Bauer Spezialtiefbau GmbH | Device and method for introducing a filling material |
| CN106013155A (en) * | 2016-05-30 | 2016-10-12 | 中国铁建大桥工程局集团有限公司 | Method for filling up covering layer and processing drilling slurry leakage by grouting consolidation |
| CN107386276A (en) * | 2017-07-20 | 2017-11-24 | 广州市建筑科学研究院新技术开发中心有限公司 | A kind of construction method of soft layer super-long and large-diameter bored piles |
| CN107938660A (en) * | 2017-11-23 | 2018-04-20 | 中交路桥华南工程有限公司 | Large diameter bored pile casing construction method |
| CN109555116A (en) * | 2018-11-08 | 2019-04-02 | 广东省第建筑工程有限公司 | A kind of high density karst intense development area fully-sleeved filled pile construction method |
-
2019
- 2019-09-09 CN CN201910848949.XA patent/CN110593254A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001214438A (en) * | 2000-02-02 | 2001-08-07 | East Japan Railway Co | Method for construction cast-in-place concrete pile, and preload device onto ground under bottom of cast-in- place concrete pile. |
| KR20100072511A (en) * | 2008-12-22 | 2010-07-01 | 재단법인 포항산업과학연구원 | Hollow steel-concrete composite cast-in-situ piles and method of carrying out construction works thereof |
| EP2712964A1 (en) * | 2012-09-26 | 2014-04-02 | Bauer Spezialtiefbau GmbH | Device and method for introducing a filling material |
| CN106013155A (en) * | 2016-05-30 | 2016-10-12 | 中国铁建大桥工程局集团有限公司 | Method for filling up covering layer and processing drilling slurry leakage by grouting consolidation |
| CN107386276A (en) * | 2017-07-20 | 2017-11-24 | 广州市建筑科学研究院新技术开发中心有限公司 | A kind of construction method of soft layer super-long and large-diameter bored piles |
| CN107938660A (en) * | 2017-11-23 | 2018-04-20 | 中交路桥华南工程有限公司 | Large diameter bored pile casing construction method |
| CN109555116A (en) * | 2018-11-08 | 2019-04-02 | 广东省第建筑工程有限公司 | A kind of high density karst intense development area fully-sleeved filled pile construction method |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113404040A (en) * | 2021-07-06 | 2021-09-17 | 中铁二十局集团第六工程有限公司 | Construction method of bored pile foundation |
| CN115110520A (en) * | 2022-04-27 | 2022-09-27 | 中国建筑第七工程局有限公司 | Construction method of bridge pile foundation on highway |
| CN115434304A (en) * | 2022-08-06 | 2022-12-06 | 河南黄河河务局工程建设中心 | Construction method for long auger bored pile super-long reinforcement cage pile-entering hole |
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Application publication date: 20191220 |