CN103758145B - Small-diameter cast-in-place tube pile composite foundation treatment method for permafrost foundation of Qinghai-Tibet highway - Google Patents
Small-diameter cast-in-place tube pile composite foundation treatment method for permafrost foundation of Qinghai-Tibet highway Download PDFInfo
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- CN103758145B CN103758145B CN201410061905.XA CN201410061905A CN103758145B CN 103758145 B CN103758145 B CN 103758145B CN 201410061905 A CN201410061905 A CN 201410061905A CN 103758145 B CN103758145 B CN 103758145B
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Abstract
The present invention relates to a kind of technology adopting minor diameter pouring pipe pile compound foundation treatment Qinghai-Tibet Highway permanent frozen soil foundation, being specially it adopts custom-designed steel pipe to become mould minor diameter (50-80cm) pouring pipe pile machine, rotates and squeeze into steel pipe cavity structure in permanent frozen soil foundation; In the hole formed after extracting steel pipe cavity structure, squeeze into insulation hollow steel pillar, then cast-in-place green concrete, extracts steel pillar after reaching some strength; The minor diameter pouring pipe pile top formed, lays sand stone layer and geo-grid.The present invention breaches the thought of passive protection permanent frozen soil foundation in the past, and the hot thaw collapse being expected to fundamentally solve Qinghai-Tibet Highway permanent frozen soil foundation falls into problem, simultaneously minor diameter pouring pipe pile of the present invention; belong to rigid pile, intensity is high, and treating depth can reach 10 ~ 30m; technique is simple, and cost is low.
Description
Technical field
The present invention relates to Qinghai-Tibet Highway permanent frozen soil foundation minor diameter (50-80cm) pouring pipe pile compound foundation treatment method, its hot thaw collapse that can solve permanent frozen soil foundation falls into problem, belongs to highway engineering construction field.
Background technology
In the process of construction of China's Qinghai-Tibet Highway and railway; the 1970's proposed the design principles and minimum roadbed height that permanent frozen soil foundation " rather fills out and do not dig "; the 1980's progressively defined the design principles of " protection of permafrost ", solved the problem of critical height of subgrade and design height.The design principles that generation nineteen ninety proposes " protection of permafrost, control melting rate and the comprehensive regulation ", gives roadbed correction critical height.Since 2000, consider the impact of climate change, further provide the principle of " refrigeration thermal resistance, reduce radiation, strengthen convection current, the comprehensive regulation ", and based on frozen soil classification, subgrade deformation and the rational height of roadbed of flexible pavement service life.Within 2004, propose that " active cooling is frozen earth roadbed, active protection ever-frozen ground " new approaches, breach traditional " passive insulation " theoretical, and have developed radiation for main sunshade roadbed, based on roadbed at the bottom of the block ground mass regulating and controlling convection current, block (broken) stone roadbed for slope protection and duct-ventilated embankment, to regulate and control heat pipe roadbed and the warming plate-heat pipe combined roadbed of conduction, and very high temperature, the engineering measures such as the viaduct that hight-ice-content permafrost district adopts, with low cost, eco-friendly mode achieves great success in Qinghai-Tibet Highway and railway subgrade in permafrost soil zone Stability Maintenance.
But, the positive effect that isolation layer roadbed reduces the heat absorption of roadbed body is not annual continuous action, it is greater than temperature in roadbed body in ambient temperature, the warm season that temperature gradient is tending towards roadbed temperature is raised just plays positive effect, that is, this measure ageing very strong in Permafrost Area.At cold season, isolation layer roadbed is unfavorable for that roadbed body and the external world carry out exchange heat, is unfavorable for that cold season roadbed body freezes for top-down time, is unfavorable for the outside transferring heat of soil body cold season under isolation layer and lowers the temperature.This illustrates, the simple engineering measure relying on thermal insulation, effectively can not change the trend that in roadbed body, heat storage increases, and the factors such as its action effect and road-trend, road structure form (with or without thermal insulation berm), roadbed height are relevant.
Rubble, sheet block-stone embankment are comparatively large to building stones demand, neighbouring with or without applicable exploitation, the building stones that meet the various aspects of performance such as intensity are designs time the problem that should consider.In addition, such as the compacting control etc. of Gravel road base construction reference goes back imperfection, the not easily Detection & Controling of construction period macadam void content.Vibrate in tunneling boring work progress compacting time rubble to two side slips, degree of compaction is more difficult reaches designing requirement.Gravel road base side slope is easily raised the fillings such as sand, and its convective cooling effect is reduced greatly.
Hot pin does not work (only occur subzero temperature in temperature fluctuation, the temperature difference at hot pin two ends exceedes just work when starting the temperature difference) substantially at warm season, this engineering measure ageing also very strong.If freezing period is short, the phase of melting is long, the freezing nucleus that hot pin is formed may melt and in roadbed, effectively can not eliminate residual thawed layer before the subzero temperature phase arrives, and the long-term effect of hot pin can not be guaranteed.The accumulation of energy effect of hot pin to frozen soil stratum is change procedure that is long-term, kinematic nonlinearity.Whether, only in cold season work, work limitation is restricted, really work, also carrying out relevant subsequent detect delay now under the theoretical startup temperature difference.Hot pin engineering measure engineering cost is high, and easily by rainwater and soil corrosion, making corrosion-resistant treatments and endurance issues become this engineering measure has problem to be solved.
The sunbreaker of steel skeleton construction, expands with heat and contract with cold in Permafrost Area seriously, and panel is yielding, damage, and structural failure is serious; And light-duty skeleton and sheet material are also comparatively subject to artificial damage or destruction.
Air chimney in actual applications, advise importing and exporting (be generally May ~ September) at air monthly mean temperature higher than the month enclosed ventilation pipeline of 0 DEG C, adopt insulating curtain that the ventilation mouth of pipe is closed (being commonly called as " drawing curtain "), utilize the way of manual adjustment, to reduce the negative effect of air chimney heat transfer.After adopting artificial measures to arrange curtain, the air chimney buried underground can make ever-frozen ground mean annual cost reduce by 1.0 ~ 2.0 DEG C.The measure of intelligence wind collecting port air chimney is also in conceptual phase now, and its effect needs to be followed the tracks of further.How to ensure compacting with whole engineering measure section around ventilation pipe foundation body, construction process control etc. also need to optimize.
From the above; existing project slash (as isolation layer, heat pipe/rod, air chimney etc.) is from passive protection permanent frozen soil foundation to initiatively protecting transformation, but its core still " protection permanent frozen soil foundation, as far as possible not disturbance or few disturbance frozen soil foundation ".From existing engineering practice, these engineering measures achieve some effects, but the hot thaw collapse of permanent frozen soil foundation falls into problem is not also solved very well.
Thinking of the present invention is the measure changing original simple protection of permafrost, takes cast-in-situ concrete in permanent frozen soil foundation to form the Treatment Methods of rigid pile, to fall into problem to the hot thaw collapse solving permanent frozen soil foundation.
Summary of the invention
Based on the problems referred to above, the object of the invention is the deficiency overcoming above-mentioned permanent frozen soil foundation resist technology, design a kind of minor diameter (50-80cm) pouring pipe pile compound foundation treatment method that permanent frozen soil foundation is punished.
Technical scheme of the present invention: Qinghai-Tibet Highway permanent frozen soil foundation punishment minor diameter pouring pipe pile compound foundation treatment method, comprises cast-in-place narrow tube pile composite foundation construction method and pile tube design of material method.
Cast-in-place narrow tube pile composite foundation construction method, its technical characteristics is:
(1) at the permanent frozen soil foundation place of pre-punishment, positioning steel tube becomes mould minor diameter pouring pipe pile machine;
(2) start the whirler power source on thin wall tubular pile machine, drive the tyre spiral steel pipe cavity structure be attached thereto to rotate together;
(3) steel pipe cavity structure squeezes into permanent frozen soil foundation under the drive of whirler, when reaching predetermined projected depth, extracts steel pipe cavity structure;
(4), in the hole formed after steel pipe cavity structure is extracted, the insulation hollow steel pillar of both ends open is squeezed into.With water pump, the ice in insulation hollow steel pillar, water, earth mixtures are drained;
(5) to disposable even injection green concrete in insulation hollow steel pillar, and vibration compacting.When concrete reaches about 70% of design strength, extract insulation hollow steel pillar;
(6) lay sand stone layer on concrete pile top, and in sand stone layer, lay geo-grid, form compound foundation mattress layer.
For the custom-designed steel pipe of said method becomes mould minor diameter pouring pipe pile machine, be primarily characterized in that, equipment Foundations are fixedly connected with the lower end, bottom of gantry support, chute is provided with inside gantry support, sliding bar is connected with the chute of gantry support, interior whirler with power source is connected under sliding bar, whirler bottom and diameter are about 50 ~ 80cm, in addition the steel pipe cavity structure of spiral to be fixed, pulley is fixed on gantry support crown center and right-hand member, sliding bar is connected with pulley power source fixing in equipment Foundations by pulley by wire rope, realizes moving up and down of sliding bar.
For the insulation hollow steel pillar of the custom-designed both ends open of said method, it is characterized in that: the thick about 5 ~ 10mm of hollow steel pillar, is with the heat insulating material of thick 2 ~ 4cm outward, the overall diameter of steel pillar and heat insulating material is slightly less than thin wall tubular pile machine and holes hole dia size.
Pile tube design of material method, its technical characteristics is:
(1) early-strength cement is adopted: grade of compressive strength is portland cement or the Portland cement of 42.5MPa; Cement consumption is no less than 300kg/m
3, water/binder ratio is not more than 0.4;
(2) about 1% air-entraining water-reducing agent is added, to reduce water supply volume;
(3) about 3% is mixed without chloride salt antifreezing agent;
(4) water and sandstone material are heated to 30 ~ 40 DEG C respectively, first drop into sandstone material and cement and mix and stir 10 ~ 20s, then add water and mix and stir 30 ~ 40s;
(5) green concrete out-of-machine temperature should not lower than 30 DEG C, and entering mould placing temperature must not lower than 25 DEG C;
(6) green concrete entered after mould is sure to vibration compacting.Then lay the moisturizing of one deck polyvinyl chloride film, then cover cotton felt and straw bag insulation.
(7) concrete reaches the 70% rear collapsible die (namely extracting insulation hollow steel pillar) of design strength, still uses heat insulating material more than covering curing 7d after form removal.
Advantage of the present invention and effect are minor diameter pile tube, belong to rigid pile, pile strength is higher, turn while the mode of pressurizeing makes treating depth to reach 10 ~ 30m, construction technology is simple, workable, is convenient to quality control, supervision, cost is low, and the stability of permanent frozen soil foundation can be made obviously to be strengthened.
Accompanying drawing explanation
The front view that Fig. 1-steel pipe of the present invention becomes mould minor diameter pouring pipe pile machine a) and side view b).
Fig. 2-insulation hollow steel pillar schematic diagram of the present invention.
Fig. 3-application example figure of the present invention.
Reference numeral:
1-equipment Foundations; 2-(is with chute) gantry support; 3-pulley power source; 4-(is with power source) whirler; 5-(tyre spiral) steel pipe cavity structure; 6-sliding bar; 7-pulley; 8-wire rope; 9-hollow steel pillar; 10-heat insulating material, 11-sand stone layer; 12-geo-grid; 13-pile tube; 14-permanent frozen soil foundation.
Detailed description of the invention
Steel pipe as shown in Figure 1 becomes mould minor diameter pouring pipe pile machine, this machine is positioned on the permanent frozen soil foundation 14 of pre-punishment, equipment Foundations 1 are fixedly connected with the lower end, bottom of gantry support 2, chute is provided with inside gantry support 2, sliding bar 6 is connected with the chute on gantry support, sliding bar 6 times companies (interior with power source) whirler 4, the steel pipe cavity structure 5 that whirler 4 bottom and diameter are about 50 ~ 80cm, in addition spiral is fixed.Fixed block power source 3 in equipment Foundations 1, gantry support 2 crown center and right-hand member fixed block 7, sliding bar 6 is connected with pulley power source 3 by pulley 7 by wire rope 8, realizes moving up and down of sliding bar 6.
Start whirler 4 power source, drive the steel pipe cavity structure 5 be attached thereto to rotate together.Open pulley power source 3, loosen the wire rope 8 on pulley 7, sliding bar 6 is made to keep whirler 4 to move downward with the chute of steel pipe cavity structure 5 along gantry support 2, rotation limit, steel pipe cavity structure 5 limit is squeezed in permanent frozen soil foundation 14, when reaching the degree of depth designed in advance, close whirler 4 power source.In rotary drilling process, check the verticality of steel pipe cavity structure 5 at any time, if any inclination, adjust in time.
Tighten up the wire rope 8 on pulley 7, upwards promote sliding bar 6, drive the whirler 4 and steel pipe cavity structure 5 that are connected with sliding bar 6, until when the least significant end of steel pipe cavity structure 5 exceeds permanent frozen soil foundation 14 surperficial more than 50cm, close pulley power source 3.Unload steel pipe cavity structure 5 and whirler 4.
In the hole that above-mentioned rotary drilling is formed, squeeze into length enough, both ends open insulation hollow steel pillar 9.With water pump, the ice in insulation hollow steel pillar 9, water, earth mixtures are drained.Disposable even injection green concrete in hole, and abundant vibration compacting.After the concrete in insulation hollow steel pillar 9 reaches more than 70% of design strength, extract insulation hollow steel pillar 9.Adopt reflective wave method to detect pile body integrity, amount detection is 25% of total amount of pile.
As shown in Figure 2, described hollow steel pillar 9 thickness of pipe wall about 5 ~ 10mm, the heat insulating material 10 of the thick 2 ~ 4cm of peripheral parcel, hollow steel pillar 9 and the overall diameter of heat insulating material 10 are slightly less than thin wall tubular pile machine and hole hole dia size.
As shown in Figure 3, lay the sand stone layer 11 of thick about 50cm on pile tube 13 top, then in sand stone layer 11, put into geo-grid 12, form compound foundation mattress layer.
Pile tube design of material:
1. early-strength, grade of compressive strength is adopted to be the Portland cement of 42.5MPa, cement consumption 350kg/m
3, water/binder ratio is 0.4.Add 1% air-entraining water-reducing agent and about 3% without chloride salt antifreezing agent.
2. at concrete agitation station, water and sandstone material (stone: sand=70:30) are heated to 40 DEG C and 30 DEG C respectively.If the temperature of water and sandstone material is higher than above temperature, then without the need to heating.
3. by the sandstone material (stone: sand=70:30) after heating and cement, put in forced concrete mixing machine, force to mix and stir 15s, then add suitable quantity of water, then force to mix and stir 40s.Green concrete out-of-machine temperature is not less than 30 DEG C.
4. will go out the green concrete after machine, in the concrete mixing and transporting car of tape loaded heat insulation function, be transported to permanent frozen soil foundation punishment on-the-spot.Remain in transportation that mixing drum rotates.
5. checking the concrete temperature transported in on-the-spot agitator truck, when being not less than 25 DEG C, in the insulation hollow steel pillar 9 draining frozen water earth mixtures, injecting concrete, while use vibrator vibration compacting.
6. after the concrete in insulation hollow steel pillar 9 all vibrates, lay the moisturizing of one deck polyvinyl chloride film thereon, then cover cotton felt and straw bag insulation.
7., after concrete reaches 70% of design strength, extract insulation hollow steel pillar 9, then continue more than maintenance 7d with heat insulating material.
Principle of the present invention can be widely used in the process of multiple permanent frozen soil foundation.
Claims (4)
1. a highway permanent frozen soil foundation minor diameter pouring pipe pile compound foundation treatment method, is characterized in that comprising the following steps:
(1) at the permanent frozen soil foundation place of pre-punishment, positioning steel tube becomes mould minor diameter pouring pipe pile machine;
(2) start the whirler power source on thin wall tubular pile machine, drive the diameter be attached thereto to be that 50-80cm, in addition the steel pipe cavity structure of spiral rotate together;
(3) loosen the wire rope on pulley that gantry support crown center and right-hand member fix, described steel pipe cavity structure squeezes into permanent frozen soil foundation under the drive of whirler, when reaching predetermined projected depth, extracts steel pipe cavity structure;
(4) in the hole formed after steel pipe cavity structure is extracted, squeeze into the insulation hollow steel pillar of both ends open, with water pump, the ice in insulation hollow steel pillar, water, earth mixtures are drained;
(5) to disposable even injection green concrete in insulation hollow steel pillar, and vibration compacting, when concrete reaches 70% of design strength, extract insulation hollow steel pillar;
(6) lay sand stone layer on concrete pile top, and in sand stone layer, lay geo-grid, form compound foundation mattress layer.
2. highway permanent frozen soil foundation minor diameter pouring pipe pile compound foundation treatment method according to claim 1, characterized by further comprising the method for designing of pile tube material, is specially:
(1) early-strength, grade of compressive strength is adopted to be silicate or the Portland cement of 42.5MPa; Cement consumption is no less than 300kg/m
3, water/binder ratio is not more than 0.4;
(2) 1% air-entraining water-reducing agent and 3% is added without chloride salt antifreezing agent;
(3) water and sandstone material are heated to 30 ~ 40 DEG C respectively, first drop into sandstone material and cement and carry out mixing and stirring 10 ~ 20s, then add water and mix and stir 30 ~ 40s;
(4) green concrete out-of-machine temperature should not lower than 30 DEG C, and entering mould placing temperature must not lower than 25 DEG C;
(5) green concrete entered after mould is sure to vibration compacting, then lays the moisturizing of one deck polyvinyl chloride film, then covers cotton felt and straw bag insulation;
(6) insulation hollow steel pillar can be extracted after concrete reaches 70% of design strength, still use heat insulating material covering curing more than 7 days.
3. the steel pipe in a kind of highway permanent frozen soil foundation minor diameter pouring pipe pile compound foundation treatment method being applied to as described in any one of claim 1-2 becomes mould minor diameter pouring pipe pile machine, it is characterized in that: equipment Foundations are fixedly connected with the lower end, bottom of gantry support, chute is provided with inside gantry support, sliding bar is connected with the chute of gantry support, interior whirler with power source is connected under sliding bar, whirler bottom and diameter are 50 ~ 80cm, the steel pipe cavity structure of spiral is fixed in addition, pulley is fixed on gantry support crown center and right-hand member, sliding bar is connected with pulley power source fixing in equipment Foundations by pulley by wire rope, realize moving up and down of sliding bar.
4. method as claimed in claim 1 or 2, the thick 5 ~ 10mm of wherein said insulation hollow steel pillar, is with the heat insulating material of thick 2 ~ 4cm outward, and the overall diameter of insulation hollow steel pillar and heat insulating material is less than thin wall tubular pile machine and holes hole dia size.
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| CN104153269B (en) * | 2014-08-22 | 2016-06-22 | 东南大学 | Ever-frozen ground guard method under a kind of wide cut road structure leading resistance combination |
| CN114197472B (en) * | 2021-12-09 | 2023-03-28 | 中煤第三建设（集团）有限责任公司 | Vibration auxiliary device for small-diameter tree root pile and using method thereof |
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