CN104499479B - It is a kind of to pass through the dug pile construction method that sand gravel backfills layer - Google Patents

It is a kind of to pass through the dug pile construction method that sand gravel backfills layer Download PDF

Info

Publication number
CN104499479B
CN104499479B CN201410791089.8A CN201410791089A CN104499479B CN 104499479 B CN104499479 B CN 104499479B CN 201410791089 A CN201410791089 A CN 201410791089A CN 104499479 B CN104499479 B CN 104499479B
Authority
CN
China
Prior art keywords
construction
caisson
sand gravel
hole
grouting pipe
Prior art date
Application number
CN201410791089.8A
Other languages
Chinese (zh)
Other versions
CN104499479A (en
Inventor
吴海清
张文龙
水伟厚
魏欢
许茂坤
戴海峰
林耀华
吴其泰
Original Assignee
上海申元岩土工程有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 上海申元岩土工程有限公司 filed Critical 上海申元岩土工程有限公司
Priority to CN201410791089.8A priority Critical patent/CN104499479B/en
Publication of CN104499479A publication Critical patent/CN104499479A/en
Application granted granted Critical
Publication of CN104499479B publication Critical patent/CN104499479B/en

Links

Classifications

    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/34Concrete or concrete-like piles cast in position ; Apparatus for making same
    • E02D5/38Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D15/00Handling building or like materials for hydraulic engineering or foundations
    • E02D15/02Handling of bulk concrete specially for foundation or hydraulic engineering purposes
    • E02D15/04Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/06Foundation trenches ditches or narrow shafts
    • E02D17/08Bordering or stiffening the sides of ditches trenches or narrow shafts for foundations
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2250/00Production methods
    • E02D2250/003Injection of material

Abstract

The dug pile construction method that sand gravel backfills layer is passed through the invention discloses a kind of, the construction method comprises the following steps:Field exploring Ground-water level and basement rock layer depth, and mark the design and construction position of caisson;A circle Grouting Pipe is squeezed into around caisson periphery vertically;By high-pressure slip-casting device, into each Grouting Pipe, injection simultaneously is mixed with the cement mortar of impervious agent, and the cement mortar is through in the injected hole infiltration sand gravel backfill layer on the slip casting tube wall, each Grouting Pipe is extracted in slip casting after finishing;After the completion for the treatment of that grouting seal water is reinforced, the cement mortar encloses concrete with affiliated sand gravel backfill layer formation one;Carry out hole excavation and carrying out retaining wall supporting in the design and construction position of the caisson afterwards, finally in described hole concrete perfusion to constitute the caisson.It is difficult to pass through the Geotechnical Engineering problem that the sand gravel that water penetration is strong, self-stability is poor backfills layer it is an advantage of the invention that solving caisson, construction safety is reliable, and pile body bearing capacity is high.

Description

It is a kind of to pass through the dug pile construction method that sand gravel backfills layer
Technical field
The invention belongs to Geotechnical Engineering foundation treatment technology field, and in particular to a kind of to pass through the borehole that sand gravel backfills layer Pile construction method.
Background technology
In recent years, continuing to develop with city, it is especially more and more nervous in coastal developed regions building site, it is many heavy Job facilities, railway, highway for wanting etc. progressively extend to the place that backfill sand gravel layer is contained in coastal waters by the natural place in inland.By In backfill sand gravel layer Lack of support to meet the requirement of engineering construction, it is therefore desirable to carry out foundation improvement to it.
Caisson is as a kind of non-Squeezing Soil Pile for improveing ground, with construction is convenient, project progress is fast, without big machinery Equipment, the advantages of anti-seismic performance is strong, so as to be widely used in Foundation Treatment.General caisson be applied to containing underground water compared with Few argillic horizon, farinose argillic horizon or clay stratum containing a small amount of sand gravel.When caisson passes through the back fill course containing sand gravel When, on the one hand because the stratum water penetration is strong, retaining wall supporting infiltration is easily caused, on the other hand because the stratum is main by loose It is poor that sand gravel constitutes self-stability, easily occurs to pass through that water penetration is strong, self-stability is poor in construction in collapse hole, therefore excavation pile construction Sand gravel backfill layer, be always the problem in Geotechnical Engineering foundation treatment technology field.
The content of the invention
The digging that sand gravel backfills layer is passed through according to the deficiencies of the prior art described above, It is an object of the present invention to provide a kind of Hole pile construction method, the construction method carries out slip casting by setting one to enclose Grouting Pipe in caisson periphery, makes the cement mortar of injection Concrete is enclosed with sand gravel backfill layer formation one, the globality of layer is backfilled so that caisson can be worn safely by improving sand gravel The more soil layer.
The object of the invention is realized and completed by following technical scheme:
It is a kind of to pass through the dug pile construction method that sand gravel backfills layer, it is characterised in that the construction method includes following step Suddenly:Examine on the spot, determine Ground-water level and basement rock layer depth, and mark the design and construction position of caisson;Around described Caisson periphery is vertical to squeeze into a circle Grouting Pipe, and each Grouting Pipe is deeply in the horizon d;Pass through high-pressure slip-casting device Into each Grouting Pipe, injection is mixed with the cement mortar of impervious agent simultaneously, and the cement mortar is through the slip casting on the slip casting tube wall Hole is penetrated into sand gravel backfill layer, stops slip casting when the cement mortar slurries amount of injection reaches design load and extracts each described Grouting Pipe;After the completion for the treatment of that grouting seal water is reinforced, the cement mortar encloses concrete with affiliated sand gravel backfill layer formation one;Exist afterwards The design and construction position of the caisson carries out hole excavation and carries out retaining wall supporting, finally the concrete perfusion in described hole To constitute the caisson.
The one circle Grouting Pipe is piled at the outer ring of the caisson vertically, and the race diameter designs for the caisson 1.1~1.3 times of aperture.
The Grouting Pipe beats pad, screwed union, slip casting plug and loose joint group by tip, steel pipe, hoop successively from bottom to top Close and constitute, wherein being evenly equipped with injected hole on the steel pipe wall.
Described hole is excavated and the construction procedure of the retaining wall supporting is:Excavation described hole is grabbed using machinery punching, in institute When stating level of ground water top excavation, 1m one section of reinforced concrete core-tube of after-pouring is often excavated;Excavated in the level of ground water bottom When, often excavate 0.5m one section of reinforced concrete core-tube of after-pouring;After the horizon d is excavated to, steel pile casting is put into the hole As supporting in hole, afterwards to progress base expanding and base expanding construction at the horizon d under workmen.
Every section of reinforced concrete core-tube is in intraoral under up-narrow and down-wide inverted trapezoidal shape, the reinforced concrete core-tube Footpath is 1.1~1.2 times of its upper internal diameter.
It is an advantage of the invention that:
(1)By in ground advanced horizontal high voltage grouting seal water reinforce to form C10 concrete, then carry out excavation pile construction, It is difficult to pass through retaining wall infiltration, the low defect of safety coefficient in sand gravel back fill course, construction so as to overcome traditional caisson;
(2)The artificial shoveling of replacement is excavated using grab jaw is rushed, number of times and time of the workmen in underground are reduced, so as to carry High efficiency of construction, reduction construction costs, raising construction safety coefficient;
(3)Replace reinforced concrete core-tube to carry out horizon d base expanding and base expanding construction using 10~15mm steel pile castings, substantially increase The security of workmen's downhole operations, in addition base expanding and base expanding construction can improve the bearing capacity at caisson stake bottom;
(4)In work progress, on the one hand stake holes wall adds the side of pile body using the concrete guard wall for adding impervious agent Frictional resistance, is effectively improved the bearing capacity of pile body, on the other hand further increases the antiseepage during excavation pile construction Performance.
Brief description of the drawings
Fig. 1 for the present invention in pass through sand gravel backfill layer caisson structural representation;
Fig. 2 is the A-A diagrammatic cross-sections in Fig. 1 of the present invention;
Fig. 3 is the structural representation of Grouting Pipe in the present invention.
Embodiment
The feature and other correlated characteristics of the present invention are described in further detail by embodiment below in conjunction with accompanying drawing, with It is easy to the understanding of technical staff of the same trade:
Mark 1-16 is respectively in such as Fig. 1-3, figure:Grouting Pipe 1, tip 2, steel pipe 3, injected hole 4, hoop are played pad 5, spiral and connect First 6, slip casting plug 7, articulation 8, horizon d 9, earth's surface 10, level of ground water 11, C10 concrete 12, reinforced concrete core-tube 13, Reinforced concrete core-tube 14, steel pile casting 15, bottom hole 16.
Embodiment:As shown in Figure 1, 2, 3, the present embodiment is specifically related to a kind of excavation pile construction for passing through sand gravel backfill layer Method, the construction method backfills layer to allow caisson to pass through the sand gravel that water penetration is strong, self-stability is poor safely, specifically applies Work step is suddenly as follows:
(1)Place is reconnoitred, the depth of level of ground water 11 and the depth of horizon d 9 is determined, in advance smooth construction site, and Groove and catch pit are excavated along bore position, is measured according to the datum mark that prospecting data is provided with axis, is measured and treat The caisson stake position central point of construction is simultaneously marked, and deviation cannot be greater than 20mm;
(2)Some Grouting Pipes 1 are transported to job site, the main body of Grouting Pipe 1 is steel pipe 3, and the length of steel pipe 3 regards basement rock Depending on the depth of layer 9, the head of steel pipe 3 is covered with aperture for that can stretch on the tip 3 of horizon d 9, its tube wall according to quincunx For 50mm injected hole 4, the spacing of adjacent injected hole 4 is 100mm, and the afterbody of steel pipe 3 is followed successively by hoop and beats pad 5, spiral shell from bottom to top Rotary joint 6, slip casting plug 7 and articulation 8, wherein hoop, which plays pad 5, is used for being fastenedly connected with vibration sinking tube equipment, screwed union 6 are used to be connected with outside slurries delivery hose, and slip casting plug 7 and articulation 8 are then defeated for fixing said external slurries Flexible pipe is sent with the connection between steel pipe 3;
(3)One circle Grouting Pipe 1, the diameter of the circle are squeezed into using vibration sinking tube equipment vertically in caisson periphery to be onstructed 1.2 times of aperture are designed for caisson so that the sand gravel backfill layer outside caisson design aperture just can be consolidated by cement grout Change and constitute entirety, immersed tube is stopped when the tip 2 of Grouting Pipe 1 passes through sand gravel backfill layer to horizon d 11;After immersed tube is finished, Grouting Pipe 1 is connected with the slurries delivery hose of said external by screwed union 6, and using the slip casting plug 7 matched And articulation 8 fixes both;
(4)Startup is same to a circle Grouting Pipe 1 by foregoing slurries delivery hose positioned at the high-pressure slip-casting device of earth's surface 10 When injection mixed with the cement mortar of impervious agent, the injected hole 4 of the cement mortar slurries of injection through being distributed on tube wall penetrates into the sand of outer ring In gravel backfill layer, grouting pressure is controlled in 2~4MPa, and slurries injection rate is preferably 15%~20%, need to be added according to caisson outer ring Solid volume can extrapolate required cement quality;Ensure that thickness of earth covering is more than 2m on slip casting point;During mortar depositing construction, use Automatic flow and press recorder, carry out data preparation analysis, slip casting are stopped when the slurries amount of injection reaches design load in time And extract Grouting Pipe;Wherein impervious agent can replace water mix slurries, with slurry reaction during, its main component producing high-molecular The atom of compound connects into linear and netted with longer branch, and impervious agent is typically all the three-dimensional knot that random distribution is presented Structure, is clouded in the macromolecular structure of slurry layer, and the capillary channel of completely plugged slurries, cement and cement mortar is had hydrophobic Property, the impermeability of concrete is improved, increases its compactness and impermeability;
(5)After the completion for the treatment of that grouting seal water is reinforced, wait cement mortar to backfill layer formation one with sand gravel and enclose the coagulation that intensity is C10 After soil 12, generally 12 hours or so, then the construction of caisson excavation and retaining wall supporting is proceeded by, in order to avoid mixed Coagulate native 12 solidification intensity really up to the mark, fraction can be attempted within 10 hours or so in maintenance and excavated, it is to avoid concrete 12 is really up to the mark to be difficult to excavate;
(6)When excavating the hole of caisson, excavation is grabbed using machinery punching and replaces hand excavation, is opened on the top of level of ground water 11 During digging, 1m one section of reinforced concrete core-tube 13 of after-pouring is often excavated;And when being excavated in the bottom of level of ground water 11, often excavate after 0.5m Pour one section of reinforced concrete core-tube 14;Wherein reinforced concrete core-tube 13 or 14 uses intensity to be made up of C25 concrete, It is furnished with equally distributed reinforcing bar, every section of reinforced concrete core-tube 13 in inside(Or 14)In up-narrow and down-wide inverted trapezoidal shape, Qi Xiakou Internal diameter is 1.1~1.2 times of its upper internal diameter;
(7)After horizon d 9 are excavated to, steel pile casting 15 is sunk in hole as inwall supporting, under supporting construction personnel The base expanding and base expanding construction of bottom hole 16 is carried out to horizon d 9, for caisson, the D/d controls of the ratio between base expanding and base expanding radius and pile body diameter 3 with It is interior, first time borehole cleaning should be carried out after pore-forming to stake end designed elevation, reaming should carry out second of borehole cleaning after finishing, steel is laid afterwards Muscle cage and conduit, then third time borehole cleaning is carried out, it can finally carry out the perfusion of pile body.
The beneficial effect of the present embodiment is:
A. the dug pile construction method in the present embodiment is applied to sand gravel and backfills layer, and sand gravel backfills layer compared to common Sandy soils, its soil particle is bigger looser, it is difficult to provide protection wall of bored pile enough supportings, the present embodiment is by using note Slurry processes make cement mortar slurries and sand gravel backfill layer fixing structure integral, are difficult to pass through sand gravel so as to overcome traditional caisson Retaining wall infiltration, the low defect of safety coefficient in back fill course, construction;In addition, thering are portion of techniques personnel to employ in borehole at present Stake periphery sets the technical scheme of high-pressure rotary jet grouting pile, but high-pressure rotary jet grouting pile can only play antiseepage effect, it is impossible to improve caisson Surrounding soil layer intensity, therefore the technical scheme of high-pressure rotary jet grouting pile is not particularly suited for sand gravel backfill this loose soil bed of layer;
B. using the artificial shoveling of grab jaw excavation replacement is rushed, number of times and time of the workmen in underground are reduced, so as to carry High efficiency of construction, reduction construction costs, raising construction safety coefficient.
C. people cannot generally be put in sand gravel back fill course under steel pile casting to bottom base expanding and base expanding, still After grouting and reinforcing in the present embodiment, sand gravel backfill layer is improved to be consolidated between globality, particle, so as to reduce pair The gusset pressure of steel pile casting wall, is put into after steel pile casting, and barrel confined pressure is reduced to the scope that can be born, so that servant enters to bottom Row base expanding and base expanding is excavated and is possibly realized, and substantially increases the security of workmen's downhole operations;
D. in work progress, on the one hand stake holes wall adds the side of pile body using the concrete guard wall for adding impervious agent Frictional resistance, is effectively improved the bearing capacity of pile body, on the other hand further increases the antiseepage during excavation pile construction Performance.

Claims (5)

1. a kind of pass through the dug pile construction method that sand gravel backfills layer, it is characterised in that the construction method includes following step Suddenly:Examine on the spot, determine Ground-water level and basement rock layer depth, and mark the design and construction position of caisson;Around described Caisson periphery is vertical to squeeze into a circle Grouting Pipe, and each Grouting Pipe is deeply in the horizon d;Pass through high-pressure slip-casting device Into each Grouting Pipe, injection is mixed with the cement mortar of impervious agent simultaneously, and the cement mortar is through the slip casting on the slip casting tube wall Hole is penetrated into sand gravel backfill layer, stops slip casting when the cement mortar slurries amount of injection reaches design load and extracts each described Grouting Pipe;After the completion for the treatment of that grouting seal water is reinforced, the sand gravel backfill layer is constituted by the grout cures is integrally formed a circle Concrete;Hole excavation is carried out in the design and construction position of the caisson and carry out retaining wall supporting afterwards, it is described when being excavated to After horizon d, steel pile casting is put into described hole as supporting, afterwards to progress base expanding and base expanding at the horizon d under workmen The ratio between construction, base expanding and base expanding radius and pile body diameter are less than 3;Finally in described hole concrete perfusion to constitute the caisson.
2. a kind of dug pile construction method for passing through sand gravel backfill layer according to claim 1, it is characterised in that one The outer ring that the Grouting Pipe is piled at the caisson vertically is enclosed, the race diameter is that the caisson designs the 1.1 of aperture ~1.3 times.
3. a kind of dug pile construction method for passing through sand gravel backfill layer according to claim 1, it is characterised in that institute Grouting Pipe is stated to be played pad, screwed union, slip casting plug and loose joint by tip, steel pipe, hoop successively from bottom to top and combined and constituted, wherein Injected hole is evenly equipped with the steel pipe tube wall.
4. a kind of dug pile construction method for passing through sand gravel backfill layer according to claim 1, it is characterised in that institute State hole excavation and the construction procedure of the retaining wall supporting is:Excavation described hole is grabbed using machinery punching, in the level of ground water When top is excavated, 1m one section of reinforced concrete core-tube of after-pouring is often excavated;When being excavated in the level of ground water bottom, often excavate One section of reinforced concrete core-tube of 0.5m after-pourings;After the horizon d is excavated to, steel pile casting is put into described hole as Supporting, afterwards to progress base expanding and base expanding construction at the horizon d under workmen.
5. a kind of dug pile construction method for passing through sand gravel backfill layer according to claim 4, it is characterised in that every Duan Suoshu reinforced concrete core-tubes are in up-narrow and down-wide inverted trapezoidal shape, and the lower internal diameter of the reinforced concrete core-tube is suitable for reading for its 1.1~1.2 times of internal diameter.
CN201410791089.8A 2014-12-19 2014-12-19 It is a kind of to pass through the dug pile construction method that sand gravel backfills layer CN104499479B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201410791089.8A CN104499479B (en) 2014-12-19 2014-12-19 It is a kind of to pass through the dug pile construction method that sand gravel backfills layer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201410791089.8A CN104499479B (en) 2014-12-19 2014-12-19 It is a kind of to pass through the dug pile construction method that sand gravel backfills layer

Publications (2)

Publication Number Publication Date
CN104499479A CN104499479A (en) 2015-04-08
CN104499479B true CN104499479B (en) 2017-09-15

Family

ID=52940922

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201410791089.8A CN104499479B (en) 2014-12-19 2014-12-19 It is a kind of to pass through the dug pile construction method that sand gravel backfills layer

Country Status (1)

Country Link
CN (1) CN104499479B (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105714771B (en) * 2016-02-18 2018-01-30 江西师范大学 A kind of construction method of artificial digging pile
CN108239985A (en) * 2016-12-27 2018-07-03 张双平 Artificial digging pile per-fore pouring liquid with small pipe pre-reinforcing construction method
CN108560540B (en) * 2018-06-20 2020-10-27 中国建筑第八工程局有限公司 Protection method and protection structure for manual hole digging pile argillaceous siltstone geology
CN110185386A (en) * 2019-06-27 2019-08-30 四川公路桥梁建设集团有限公司 A kind of incompact-deposit bodies stratum concrete guard wall rotary digging fast pore-creating method
CN110258551A (en) * 2019-06-27 2019-09-20 四川公路桥梁建设集团有限公司 A kind of vertical ductule pipe curtain supporting construction of friction pile pore digging and construction method
CN111197310A (en) * 2020-01-07 2020-05-26 中冶交通建设集团有限公司 Grouting device, equipment and grouting method for sounding pipe of water-rich stratum of cast-in-place pile
CN111173991A (en) * 2020-02-14 2020-05-19 广东君兆建设集团有限公司 Municipal road pipeline construction method
CN111172982A (en) * 2020-02-17 2020-05-19 中冶建工集团有限公司 Construction method of soft soil manual hole digging pile

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2469046Y (en) * 2001-04-04 2002-01-02 陈扬德 Prefabricated steel bar reinforced concrete bulk head for piles
CN101200897A (en) * 2007-11-20 2008-06-18 中铁大桥局集团第二工程有限公司 Construction method for grouting curtain combined with steel reinforced concrete guard ring
CN101525881B (en) * 2009-04-01 2012-01-04 中铁二院工程集团有限责任公司 Structure of karst strata pile holes protecting wall and method for constructing pile holes
CN103031839B (en) * 2013-01-10 2015-04-15 中铁七局集团第三工程有限公司 Construction method of hand-dug piles

Also Published As

Publication number Publication date
CN104499479A (en) 2015-04-08

Similar Documents

Publication Publication Date Title
CN105041325B (en) Construction method of high-tension water-rich extra-large-section weak breccia tunnel
CN103089275B (en) Control method of surrounding rocks in water-rich very-broken surrounding rock tunnel collapse sections
CN103590425B (en) A kind of Peaty soft soil stratum subway station construction technology
CN103343544B (en) Construction method for large-scale open caisson
CN104612162B (en) A kind of Deep Foundation Pit of Metro Stations excavation construction method
CN104818991B (en) A kind of construction method in Shallow-buried residual soil slope tunnel
CN104631470B (en) The large particle diameter sand gravel of high water level geology deep basal pit combination supporting construction method
CN100497841C (en) Supporting leg type underground continuous wall construction method
CN101962949B (en) Long spiral double-pipe high-pressure stir-jet grouting pile construction method and device
CN101638891B (en) Construction method of all casing precessing isolation pile
CN100591866C (en) Drifting sand layer and gravel stratum water-moving double-liquid high pressure slip-casting water-blocking construction method
CN106545005B (en) A kind of reinforcing body and reinforcement means of subway tunnel shield end
CN104453913B (en) A kind of Shaft Stopes front pre-grouting method
CN102518135B (en) Horizontal jet grouting soil anchor and castinplace pile Composite Foundation Pit supporting construction engineering method
CN103485336A (en) Drilling pile drilling construction method of bead-type karst area
CN106436596B (en) A kind of construction method for highway fiberglass sand inclusion pipe culverts
CN104453946B (en) Advanced reinforcing construction method for building tunnel in soft surrounding rock
CN106284313B (en) Long spire based on circulating mud retaining wall is squeezed into rock filling pile construction method
CN103233454B (en) Processing method of soaking, vacuum preloading and slurry injecting for sand piles of collapsible loess foundation
CN103924987B (en) A kind of SMW engineering method stake tunnel shielding portal seepage-proof structure and construction method thereof
CN107642360A (en) Tunneling boring front pre-grouting construction method
CN102691296A (en) Pipe pile foundation for static-pressure grouting on pile side and rotary jet grouting at pile bottom and construction method thereof
CN101525881B (en) Structure of karst strata pile holes protecting wall and method for constructing pile holes
CN104612143B (en) Composite pile constructed in drilled hole structure under a kind of solution cavity/soil cave geological conditions
CN102454167A (en) Construction method for large ultra-deep well

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant