CN102661154A - Double-layer structural concrete for lining tunnel under condition of terrestrial heat erosion and construction method of double-layer structural concrete - Google Patents
Double-layer structural concrete for lining tunnel under condition of terrestrial heat erosion and construction method of double-layer structural concrete Download PDFInfo
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- CN102661154A CN102661154A CN2012101480562A CN201210148056A CN102661154A CN 102661154 A CN102661154 A CN 102661154A CN 2012101480562 A CN2012101480562 A CN 2012101480562A CN 201210148056 A CN201210148056 A CN 201210148056A CN 102661154 A CN102661154 A CN 102661154A
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Abstract
The invention discloses a double-layer structural concrete for lining a tunnel under the condition of terrestrial heat erosion and a construction method of the double-layer structural concrete. The double-layer structural concrete consists of structural layer concrete and protective layer concrete, wherein a structural layer is made of common C30 reinforced concrete; a protective layer is made of C20 composite concrete. In the constructing process, double mold setting and laminated pouring modes are adopted, namely the protective layer is poured under the condition of setting one mold, the mold is removed while 75 percent of a designed strength level is reached through maintenance, the surface of the concrete of which the mold is removed is subjected to artificial scabbling and slag cleaning, and a template of the structural layer is erected to pour the structural layer. The condition of constructing the structural layer concrete under the condition of terrestrial heat is improved by the protective layer, a temperature difference between the inside and the outside of the structural layer under the normal operation condition is reduced by using the heat insulating effect of the protective layer, and the protective layer is high in crack resistance and erosion resistance, so that the integral stability and durability of a tunnel lining concrete structure are further improved.
Description
Technical field
The invention belongs to water conservancy and civil engineering material technical field, be specifically related under a kind of underground heat eating condition tunnel lining with double-decker concrete and job practices thereof.
Background technology
Hot conditions that occurs in the engineering and groundwater erosion problem have adverse effect to the concrete lining durability of structures.Higher as if building with the temperature of duration of coagulation, the intensity of phase is improved though make very early, after building 7 days; Just can produce adverse influence to concrete intensity; Tracing it to its cause mainly is, the fast hydration at initial stage certainly will form the bad hydrate of physical arrangement; And mostly be loose structure, so that most of space is still keeping the state that is not filled.Can infer than (ratio of the volume of water of hydration mud and water of hydration mud and pore volume sum) criterion by the glue sky, will cause the decline of intensity, though, reach the higher empty ratio of glue in the slurry at last because few pore structure hydration is slow.Early stage high temperature has this explanation of adverse effect to be extended by Fu Beike (Verbek) and wrong this (Helmuth) of Haier to later strength; They think that the quickening of initial hydration speed has slowed down hydration rate after this under the higher temperature, and have produced the hydrated product of uneven distribution in slurry inside.Its reason is that under initial hydration speed higher temperature, the hydrated product that has left cement granules also has little time diffusion does not have time enough to make its homogeneous precipitation in the inner space yet.Therefore, just around the cement granules of aquation, assembling the hydrated product of high concentration, this has just slowed down hydration rate after this and concrete later strength has been produced adverse influence.In addition, the uneven distribution of hydrated product itself has a negative impact to intensity, because the glue of this inner space is empty than being lower than the identical but empty ratio of glue under the distribution uniform situation of degree of hydration, like this, local weak spot makes the intensity reduction of whole slurry.There are some researches show that in addition initial temperature is high more, final strength is low more.
Having found more than 100 ℃ under the hot conditions that the concrete of maintenance is exposed under ambient temperature usually subsequently may make usefulness reduce in the moisture; This phenomenon is called the formation that postpones entringite (32 water trithio aluminic acids, six calcium); Be characterized in around some aggregate particle, producing " breach ", these breaches often contain the entringite that compresses.Prolonging entringite generation (DEF) is a kind of sulfate attack form, has destroyed entringite-sulfate mainly due to high temperature, and aluminate, and there are indications that above-mentioned salt is absorbed by C-S-H.During cooling, sulfate possibly form entringite again, and with corresponding volume expansion.This expansion causes forming at the aggregate particle place of closing on the entringite of thick crystallization, produces internal stress simultaneously, causes cracking at last.DEF cutter reason really it be not immediately clear, is the prerequisite that DEF produces undesirable extention because of other reasons (like alkali ASR or temperature gradient) causes initial damage still.
Because when building tunnel engineering in the area of topography and geomorphology, complicated geologic conditions; Tend to run into the construction puzzlement of high underground heat; Usually be difficult to satisfy requirement of engineering if still adopt the conventional monolayers concrete this moment, also certainly will have a strong impact on concrete intensity and durability; And concrete service life is lower, and engineering safety is brought hidden danger.
Summary of the invention
The problem that adopts for solving the conventional monolayers concrete to produce, the present invention provides under a kind of underground heat eating condition tunnel lining to use the double-decker concrete, and this tunnel lining concrete is made up of deck concrete and topping concrete; Wherein, deck adopts common C30 steel concrete, and topping adopts the C20 composite concrete, and it is by water 122kg/m
3, cement 240kg/m
3, fine aggregate 750kg/m
3, coarse aggregate 1233kg/m
3, pozzolan 48kg/m
3, water reducing agent 2.88kg/m
3, polypropylene fibre 1.8kg/m
3With acrylate copolymer emulsion 36kg/m
3The composite concrete that mixed proportion forms.Improve deck Concrete Construction condition under the ground heat condition by topping; And utilize the heat insulation effect of topping to reduce deck inside and outside temperature difference under the normal running (operation) conditions; Have stronger cracking resistance and corrosion resistance owing to topping simultaneously, thereby further improve the resistance to overturning and the endurance quality of tunnel lining concrete structure.The present invention is fit to tunnel support under underground heat and the erosion environment, is particularly suitable for the tunnel operation phase because the complicated bottom tunnel support of ground heat condition lining concrete grade easy to crack.
The present invention also provides under this underground heat eating condition tunnel lining with double-decker Concrete Construction method; This double-decker concrete is made up of deck concrete and topping concrete; Wherein, Deck adopts common C30 steel concrete, and topping adopts the C20 composite concrete, and it is by water 122kg/m
3, cement 240kg/m
3, fine aggregate 750kg/m
3, coarse aggregate 1233kg/m
3, pozzolan 48kg/m
3, water reducing agent 2.88kg/m
3, polypropylene fibre 1.8kg/m
3With acrylate copolymer emulsion 36kg/m
3The composite concrete that mixed proportion forms.During construction; Take the mode of upright bimodulus, placement layer by layer, promptly under the situation of formwork erection, carried out building of topping, form removal in 75% o'clock of maintenance to design strength grade earlier; After concrete surface after the form removal carried out manual work cutter hair, scarfing cinder, the template of the upright deck of frame and building again.According to the present invention; Improve deck Concrete Construction condition under the ground heat condition by topping; And utilize the heat insulation effect of topping to reduce deck inside and outside temperature difference under the normal running (operation) conditions; Have stronger cracking resistance and corrosion resistance owing to topping simultaneously, thereby further improve the resistance to overturning and the endurance quality of tunnel lining concrete structure.
Tunnel lining is with double-decker concrete and job practices thereof under this underground heat eating condition of the present invention's design; To the underground heat special environmental conditions; Become possibility for improving tunnel lining concrete overall durability; Started the new method of tunnel lining supporting under a kind of underground heat eating condition, certain theory foundation and technological guidance are provided, had important social benefit and huge economic benefit for solving the similar engineering problem.
Description of drawings
Fig. 1 is a topology view of the present invention.
Label among the figure: 1 is topping, and 2 is deck.
The specific embodiment
The double-decker concrete that tunnel lining is used under the underground heat eating condition provided by the invention is as shown in Figure 1, and the specific embodiment is following:
(1) carries out the theoretic throat of topping through heat engineering heat conduction principle; Guaranteeing under the stable prerequisite of tunnel structure layer; Simultaneous is confirmed the tunnel excavation width, proposes to adopt the thick double layer concrete composite support of 60cm structure, and its topping 20cm is the C20 composite concrete; Deck 40cm is the C30 concrete, and is as shown in Figure 1.
(2) through in concrete, mixing an amount of pozzolan, polypropylene fibre and acrylate copolymer emulsion; Can significantly improve the concrete cracking resistance of tunnel lining, erosion-resisting characteristics and heat-proof quality; To reach the deck Concrete Construction condition under the ground heat condition of improving; Reduce deck inside and outside temperature difference under the normal running (operation) conditions, guarantee the normal setting and harden of tunnel structure layer concrete under the underground heat.
(3) to the construction period geothermal vapour, concentrate the adverse effect of spring to concrete moulding and early curing; According to its distribution situation; Arrange Φ 50mm steel pipe in the relevant position; Through steel pipe geothermal vapour and spring are concentrated outside the outer template storehouse face that is directed at the topping construction, reduced it and in the country rock body, accumulate intensification.
The present invention is different with the concrete-lined action principle of conventional monolayers; Effectively improving deck Concrete Construction condition under the ground heat condition; And under the reduction normal running (operation) conditions deck inside and outside temperature difference time, fundamentally solved the problem that tunnel concrete can't normally condense hydration and hardening under the underground heat.In actual engineering, can utilize this method for designing to come quantitatively control tunnel lining double layer concrete thickness separately, and then the stable purpose of control structure layer, when reaching tunnel structure safety, realize the designing requirement that it is durable.Because the difference of geotemperature, protective layer thickness need carry out Theoretical Calculation through heat engineering heat conduction principle and confirm when design, and cooperates and indoorly unite definite with field trial.
Carry out the theoretic throat of topping through heat engineering heat conduction principle; Guaranteeing under the stable prerequisite of tunnel structure layer; Simultaneous is confirmed the tunnel excavation width; Through in concrete, mixing an amount of pozzolan, polypropylene fibre and acrylate copolymer emulsion, can significantly improve the concrete cracking resistance of tunnel lining, erosion-resisting characteristics and heat-proof quality, to reach the deck Concrete Construction condition under the ground heat condition of improving; Reduce deck inside and outside temperature difference under the normal running (operation) conditions, guarantee the normal setting and harden of tunnel structure layer concrete under the underground heat.Simultaneously; To the construction period geothermal vapour, concentrate the adverse effect of spring to concrete moulding and early curing; According to its distribution situation; Arrange Φ 50mm steel pipe in the relevant position, geothermal vapour and spring are concentrated outer being directed at outside the template storehouse face that topping constructs, reduce it and in the country rock body, accumulate intensification through steel pipe.
Continuous propelling along with China's engineering construction task; The construction task of the simple relatively engineering of original geology, landform has moved closer to coda; The hydraulic engineering of follow-up construction will face more complicated construction technical difficulty and the execution conditions that become increasingly complex; So under the underground heat eating condition, in the high temperature rock mass, build tunnel, thereby realization fundamentally improves the purpose of the normal setting and harden of tunnel construction condition and lining concrete through the method for designing that adopts the double-decker lining concrete; And then proposition improves the method for concrete durability of tunnel lining and safety; Therefore, tunnel lining will bring huge economic and social benefit with the proposition of double-decker concrete design method under a kind of underground heat eating condition.
Through concrete performance test, the result shows that the topping concrete has sheath and has stronger cracking resistance, corrosion resistance and heat insulation effect, thereby further improves the resistance to overturning and the endurance quality of tunnel lining concrete structure:
(1) corrosion resistance
Mortar specimen adopts the mould of 70mm * 70mm * 20mm, and form removal behind the moulding 1d is taken out behind the 28d under the standard conditions maintenance; Behind drying in oven 2h, weigh; It is immersed in respectively in 5%, 10%, 15% the sulfuric acid solution again, takes out behind the 4h, oven dry 2h weighs again; Oven dry 2h weighs after continuing to soak 4h, calculates its mass loss rate.
Result of the test shows, mix polypropylene copolymer emulsion and pozzolan again after, significantly improved the microstructure of cement mortar; The compactness of mortar is further strengthened; And contrast different polymer cement ratios and pozzolan replacement rate, when drawing pozzolan and polypropylene copolymer emulsion and mixing again, pozzolan replacement rate is 17%; The polymer cement ratio optimum ratio is 0.25 o'clock, and the decay resistance of mortar is best.
Table 1 corrosion resistance result of the test
(2) mechanical property of polypropylene fibre and crack resistance
The concrete shrinkage test is carried out according to DL/T5150-2001 " concrete for hydraulic structure testing regulation "
Table 2 is mixed with the strength test result of polypropylene fiber concrete
Table 3 polypropylene fiber concrete cracking test result
Annotate: the weights data are: d>=3 get 3; 3>d>=2 get 2; 2>d>=1 gets 1; 1>d>=0.5 gets 0.5;<0.5 gets 0.25 to d.
The volume of design polypropylene fibre is respectively 0.45kg/m
3, 0.9kg/m
3, 1.8kg/m
3, 3.6kg/m
3, from the influence of aspect research polypropylene fibres such as compressive strength, split tensile strength and crack resistance to concrete performance, result of the test shows: polypropylene fibre V
f=1.8kg/m
3The time, it is to improving concrete intensity and crack resistance best results.
(3) mechanical property of lining concrete
The result obtains by afore-mentioned test; Pozzolan, polypropylene fibre and polymer (acrylate copolymer emulsion) optimum volume separately; On this basis; Receive underground heat and groundwater erosion synergy to this engineering, for realizing collection concrete mix setting and harden, concrete anticracking, anti-erosion and Stability Analysis of Structures function integration concrete composite support structure, the mode that adopts polypropylene fibre, pozzolan and combination of polymers to mix is again carried out topping C20 and the design of deck C30 match ratio.
Table 4 concrete strength test result
Result of the test shows that deck C30 concrete and each assembly of topping C20 concrete all satisfy its compressive strength, split tensile strength and modulus of elasticity and all reached designing requirement.It is cracking resistance, anticorrosion and heat insulation that the topping concrete of design mainly acts on; Compressive strength does not play conclusive effect; Through in the topping concrete, having mixed auxiliary materials such as polypropylene fibre, pozzolan and polymer; Make it under underground heat and groundwater erosion effect, its cracking resistance and Corrosion Protection significantly improve, thereby have guaranteed that the tunnel lining structure has resistance to overturning and durability.
(4) the concrete Temperature Distribution of tunnel lining
Choose 60 ℃, 80 ℃, 100 ℃ and 130 ℃ of four environment temperatures, through the temperature on the interior different section of ordinary concrete and composite protection layer concrete sample being tested the heat insulation effect of simulation geothermal action lower protective layer composite concrete.
Temperature Distribution under the different geotemperatures of table 5 simulation on the concrete different measuring points
Annotate: No. 1 measuring point---thermal source closely; No. 2 measuring points---concrete center; No. 3 measuring points---near room temperature.The interior temperature of testing the same day is 20 ℃.
Result of the test shows; The composite concrete of topping has heat-proof quality preferably under the effect of underground heat, can reduce surface temperature of concrete effectively; Thereby deck inside and outside temperature difference under the reduction normal running (operation) conditions plays the effect that improves deck Concrete Construction condition under the ground heat condition.
On this basis; Through field engineering prototype temperature detection; Disclose the time-varying process of each layer of concrete structure temperature of ground hot arc, and the spatial distribution situation of each layer of underground heat section concrete structure thermal field, the result shows; Tunnel topping composite concrete has good effect of heat insulation in whole lining cutting section; Its heat insulation effect has significantly reduced deck inside and outside temperature difference under the normal running (operation) conditions, and topping has stronger crack resistance and corrosion resistance simultaneously, has improved the durability of lining concrete.
Claims (2)
1. tunnel lining is used the double-decker concrete under the underground heat eating condition, it is characterized in that being made up of deck concrete and topping concrete, and wherein, deck adopts common C30 steel concrete, and topping adopts the C20 composite concrete; Said topping is by water 122 kg/m
3, cement 240kg/m
3, fine aggregate 750kg/m
3, coarse aggregate 1233 kg/m
3, pozzolan 48 kg/m
3, water reducing agent 2.88 kg/m
3, polypropylene fibre 1.8kg/m
3With acrylate copolymer emulsion 36kg/m
3Mix the composite concrete that forms.
Under the underground heat eating condition as claimed in claim 1 tunnel lining with double-decker Concrete Construction method; It is characterized in that: during construction; Take the mode of upright bimodulus, placement layer by layer, promptly under the situation of formwork erection, carried out building of topping, form removal in 75% o'clock of maintenance to design strength grade earlier; After concrete surface after the form removal carried out manual work cutter hair, scarfing cinder, the template of the upright deck of frame and building again; Improve deck Concrete Construction condition under the ground heat condition by topping; And utilize the heat insulation effect of topping to reduce deck inside and outside temperature difference under the normal running (operation) conditions; Have stronger cracking resistance and corrosion resistance owing to topping simultaneously, thereby further improve the resistance to overturning and the endurance quality of tunnel lining concrete structure.
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Cited By (5)
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| CN105731916A (en) * | 2014-12-09 | 2016-07-06 | 贵州省建材产品质量监督检验院 | Dense polymer emulsion-fiber combined modified cement concrete functional layer |
| CN110593891A (en) * | 2019-09-11 | 2019-12-20 | 中铁时代建筑设计院有限公司 | Shield tunnel for energy exchange and construction method thereof |
| CN111255485A (en) * | 2020-03-03 | 2020-06-09 | 中煤科工集团重庆研究院有限公司 | Deep well roadway supporting structure and construction method |
| CN111606619A (en) * | 2019-12-18 | 2020-09-01 | 中国铁道科学研究院集团有限公司铁道建筑研究所 | Corrosion-resistant concrete for tunnel lining |
| WO2023206972A1 (en) * | 2022-04-29 | 2023-11-02 | 中交四航工程研究院有限公司 | Method for improving durability of cast-in-place concrete structure in tidal range zone of marine environment |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105731916A (en) * | 2014-12-09 | 2016-07-06 | 贵州省建材产品质量监督检验院 | Dense polymer emulsion-fiber combined modified cement concrete functional layer |
| CN110593891A (en) * | 2019-09-11 | 2019-12-20 | 中铁时代建筑设计院有限公司 | Shield tunnel for energy exchange and construction method thereof |
| CN111606619A (en) * | 2019-12-18 | 2020-09-01 | 中国铁道科学研究院集团有限公司铁道建筑研究所 | Corrosion-resistant concrete for tunnel lining |
| CN111255485A (en) * | 2020-03-03 | 2020-06-09 | 中煤科工集团重庆研究院有限公司 | Deep well roadway supporting structure and construction method |
| WO2023206972A1 (en) * | 2022-04-29 | 2023-11-02 | 中交四航工程研究院有限公司 | Method for improving durability of cast-in-place concrete structure in tidal range zone of marine environment |
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Application publication date: 20120912 |