Anti-settling and replacement-filling alternate airport runway and construction method thereof
阅读说明：本技术 一种防沉降换填交替机场跑道及其施工方法 (Anti-settling and replacement-filling alternate airport runway and construction method thereof ) 是由 刘朝阳 王甜 于 2019-12-09 设计创作，主要内容包括：本发明提出了一种防沉降换填交替机场跑道及其施工方法,主要是通过在换填交替机场跑道施工的开挖段铺设一种吸水膨胀、失水收缩,在含水量变化时具有明显胀缩变形的膨润土复合层；在换填交替机场跑道施工的填埋段采用具有承载力大,地基沉降变形小的CFG桩褥垫层复合地基的方法；分别对开挖、填埋段的路基基层整平夯实,压实度达85％以上,对开挖、填埋段的交界处用膨润土填充密实,经过处理后使得两段路基表面平整光滑,最终使得换填交替机场跑道的开挖段和填埋段的路基能够达到同步均匀沉降的目的,从而保证换填交替机场跑道在使用过程中的安全性。(The invention provides an anti-settling alternate airport runway and a construction method thereof, which is mainly characterized in that a bentonite composite layer which absorbs water to expand and loses water to contract and has obvious expansion and contraction deformation when the water content changes is laid at the excavation section of the alternate airport runway construction; a method of CFG pile mattress layer composite foundation with large bearing capacity and small foundation settlement deformation is adopted at the landfill section of the replacement and filling alternate airport runway construction; the roadbed base layers of the excavation section and the landfill section are respectively leveled and tamped, the compaction degree reaches more than 85%, the junction of the excavation section and the landfill section is densely filled with bentonite, the surfaces of the two sections of roadbeds are leveled and smooth after treatment, and finally the roadbeds of the excavation section and the landfill section of the replacement and landfill alternate airport runway can achieve the purpose of synchronous uniform settlement, so that the safety of the replacement and landfill alternate airport runway in the using process is ensured.)
1. The utility model provides a prevent subsiding and trade and fill out airport runway in turn, includes the road bed and is located the road bed packing layer on the road bed, the road bed includes excavation section and landfill section again, the bentonite composite bed has been laid to the excavation section, the landfill section is including the complex ground that has CFG stake and mattress pad layer, CFG stake erects in the ground, mattress pad layer is laid in the ground top, the excavation section with the juncture of landfill section is filled there is bentonite and two sections upper surfaces to be located same horizontal plane.
2. The anti-settling alternate airport runway of claim 1, wherein a concrete structure base course and a gravel cushion course are laid below the bentonite composite layer in sequence, and a mattress cushion course is laid above the bentonite composite layer.
3. The anti-settling alternate airport runway of claim 1 or 2, wherein the bentonite composite layer comprises a bentonite waterproof system, bentonite and bentonite clay skin in sequence from bottom to top, and the bentonite waterproof system comprises a non-woven fabric layer, a waterproof material layer and a woven fabric layer in sequence from bottom to top.
4. The anti-settling alternate airport runway of claim 3, wherein the bentonite composite layer has no impurities of more than 10mm and has a compactness of more than 85%.
5. The anti-settling alternate airport runway of claim 1 or 2, wherein the mattress layer comprises crushed stones, medium grit and geogrids from bottom to top, the maximum particle size of the crushed stones being no greater than 25 mm.
6. A construction method for preventing settlement and replacing alternate airport runways comprises the following steps:
1) leveling the field after the excavation of the roadbed excavation section is finished, and paving a bentonite composite layer;
2) the soil body and the broken stones of the roadbed excavation section are conveyed to a landfill section for landfill, and after a construction site is leveled, the construction of CFG piles and mattress layers is carried out;
3) and densely filling the junction of the excavation section and the landfill section with bentonite, finally enabling the excavation section and the landfill section to reach the same flat surface, and then constructing a roadbed packing layer.
7. The construction method of claim 6, wherein in the step 1), the base layer is leveled and tamped before the bentonite composite layer is laid, a crushed stone cushion layer is laid on the leveled base layer, then a concrete structure base layer is poured, the bentonite composite layer is laid, then a mattress layer is laid, and the base layer is tamped, so that the degree of compaction reaches more than 85%, the surface is smooth and smooth, and no sundries with the length of more than 2cm protrude.
8. The construction method of the anti-settling and alternate-filling airport runway according to claim 6, characterized in that in the step 2), after filling, a heavy vibration roller is used for compacting and reinforcing the construction site, and a test section rolling test is carried out before rolling formal construction.
9. The construction method of the anti-settling alternate airport runway of claim 6, wherein in step 2), a long auger drilling machine is used for CFG pile construction, and the pipe drawing rate is 1.2-1.5 m/min during pile forming.
10. The construction method of claim 6, wherein in the step 2), 10-12% stone powder or fine particles are mixed into the gravel with the maximum particle size of not more than 25mm, and the mixture is uniformly mixed and filled.
Technical Field
The invention relates to the technical field of airport construction, in particular to an anti-settling alternate-filling airport runway and a construction method thereof.
Background
With the development of modern society and the progress of science and technology, the living standard of people is improved, and an airplane, as a convenient and quick novel vehicle, becomes more and more the first choice of people going on a journey. The rapid development of air transportation is directly promoted by the ever-growing economic strength and the omnibearing open pattern all over the country. The construction of airports in mountainous, hilly and coastal areas also becomes a trend, wherein in the main construction works of airports, airport runways can be said to be one of the most important buildings, and their importance is also self evident. The airport runway is the construction key point in airport construction and is an important link for ensuring smooth operation of the airport. The quality of the construction quality of the airport runway also seriously influences whether the airplane can take off and land smoothly, and except the poor construction quality, the uneven settlement of the soil foundation is always a great problem for the runway construction, and particularly the uneven settlement of the airport runway caused by the alternate filling and replacement construction in mountains, hills and coastal areas is the most obvious problem. The uneven settlement of the foundation is the main reason for causing the uneven settlement of the roadbed, so that the development of the uneven settlement control research of the soil foundation has very important practical significance for the construction of airport runways.
Disclosure of Invention
In order to solve the problems, the invention provides an anti-sedimentation and anti-filling alternate airport runway and a construction method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a settlement-prevention replacement and filling-alternation airport runway, which comprises a roadbed and a roadbed filling layer positioned on the roadbed, wherein the roadbed also comprises an excavation section and a filling-in section, a bentonite composite layer is laid on the excavation section, the filling-in section comprises a foundation compounded with a CFG (cement fly ash) pile and a mattress layer, the CFG pile is vertically arranged in the foundation, the mattress layer is laid above the foundation, the junction of the excavation section and the filling-in section is filled with bentonite, and the upper surfaces of the two sections are positioned on the same horizontal plane.
Preferably, a concrete structure base layer and a broken stone cushion layer are sequentially paved below the bentonite composite layer, and a mattress cushion layer is paved above the bentonite composite layer.
Preferably, the bentonite composite bed from the bottom up includes bentonite waterproof system, bentonite and bentonite crust in proper order, bentonite waterproof system from the bottom up includes non-woven fabrics layer, waterproof material layer and braided fabric layer in proper order.
Preferably, the bentonite of the bentonite composite layer has no impurities with the thickness of more than 10mm and the compactness of more than 85 percent.
Preferably, the mattress layer comprises broken stones, medium coarse sand and geogrid from bottom to top.
More preferably, the maximum particle size of the crushed stone is not more than 25 mm.
The invention also provides a construction method for preventing settlement and changing and filling alternate airport runways, which comprises the following steps:
1) leveling the field after the excavation of the roadbed excavation section is finished, and paving a bentonite composite layer;
2) the soil body and the broken stones of the roadbed excavation section are conveyed to a landfill section for landfill, and after a construction site is leveled, the construction of CFG piles and mattress layers is carried out;
3) and densely filling the junction of the excavation section and the landfill section with bentonite, finally enabling the excavation section and the landfill section to reach the same flat surface, and then constructing a roadbed packing layer.
Preferably, in step 1), before laying the bentonite composite layer, the base layer is leveled and tamped, after laying the gravel cushion layer on the leveled base layer, a concrete structure base layer is poured, the bentonite composite layer is laid (including construction of a bentonite waterproof system, the bentonite waterproof system comprises a non-woven fabric layer, a waterproof material layer and a woven fabric layer, then the bentonite is laid, and a layer of bentonite clay skin is laid on the surface of the bentonite for waterproof treatment), then a mattress layer is laid, and the base layer is compacted, wherein the compaction degree reaches more than 85%, the surface is smooth and smooth, and no sundries more than 2cm protrude.
Preferably, in the step 2), after landfill, a heavy vibration roller is adopted to compact and reinforce the construction site, and a test section rolling test is carried out before rolling formal construction.
Preferably, in step 2), the construction of the CFG pile is performed using a long auger drilling machine.
More preferably, the pipe drawing speed is 1.2-1.5 m/min when the pile is formed.
Preferably, in the step 2), when the mattress layer is constructed, 10-12% of stone powder or fine particles are mixed into the gravel with the maximum particle size of not more than 25mm, and the gravel is uniformly mixed and filled.
Compared with the prior art, the invention has the following beneficial effects:
the bentonite in the bentonite composite layer of the excavation section has the engineering characteristics of water absorption expansion and water loss contraction, the deformation of the excavation section can be effectively controlled by the processing of a bentonite waterproof system, the bentonite waterproof system is combined with the characteristics of large bearing capacity and small deformation of the composite foundation of the CFG pile mattress layer of the landfill section, the damage to the foundation caused by overlarge settlement or uneven settlement of the foundation can be reduced by adopting a proper processing mode, the even settlement of the roadbed of the replacement and filling alternate airport runway can be realized, and the safety of the replacement and filling alternate airport runway is ensured. The invention can provide guidance for the field and can also be used for teaching and scientific research in the field.
Drawings
Fig. 1 is a schematic structural diagram of an anti-settling alternate airport runway.
In the figure, 1 is the excavation section, 2 is the landfill section, 3 is the bentonite composite bed, 4 is the CFG stake, 5 is the soil layer, 6 is the mattress layer, 7 is the roadbed packing layer.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
The construction materials, equipment and methods used in the present application can be implemented using existing technologies, unless otherwise specified.
As shown in figure 1, the settlement-prevention and replacement-filling alternate airport runway provided by the invention comprises a roadbed and a roadbed filling layer 7 positioned on the roadbed, wherein the roadbed comprises an excavation section 1 and a
The construction method for preventing settlement and replacing and filling alternate airport runways comprises the following steps:
the method comprises the steps of firstly, at a construction excavation section of a replacement and filling alternative airport runway, conveying soil bodies of the replacement and filling alternative airport runway construction excavation, and filling gravels into a landfill section, leveling the site after the site excavation is finished, paving a gravels cushion layer, a concrete structure base layer and a bentonite waterproof system before the bentonite is paved, paving a layer of bentonite clay skin on the surface of the bentonite for waterproof treatment after the bentonite is paved, paving a mattress cushion layer, and finally leveling and compacting the base layer by adopting equipment, wherein the compaction degree is more than 85%, the surface is level and smooth, rocks and other objects which protrude by more than 2cm cannot exist, the surface is basically dry, obvious water accumulation cannot exist, and drainage operation is carried out if the water accumulation exists. The construction of the bentonite is carried out in rainy or snowy weather, and a plastic film is used for covering when the bentonite is in rain or snow, so that the bentonite is prevented from being hydrated in advance. The backfill soil is preferably sand or soil after sieving, and the soil cannot contain impurities such as stones with the thickness of more than 10 mm. The backfill needs to be tamped (or compacted, vibrated, etc.), and the compactness of the backfill needs to be more than 85%.
The bentonite has the engineering characteristics of water absorption expansion and water loss contraction. Bentonite, in addition to deforming under load, also undergoes significant expansion and contraction deformation when the water content changes. The wet expansion deformation under the combined action of external load and soaking, and the drying shrinkage deformation under the combined action of external load and evaporation, air drying, water level reduction and the like.
And secondly, in a construction landfill section of the replacement and filling alternate airport runway, after soil and gravels of the construction excavation section of the replacement and filling alternate airport runway are buried, leveling the site, compacting and reinforcing by adopting a heavy vibration road roller, and performing a test section rolling test before rolling formal construction. And (3) leveling a construction site, lofting after measurement, and constructing the CFG pile by using a long spiral drilling machine, wherein in the construction process, a proper pile-forming construction process is selected according to the environment, and the pipe drawing speed is controlled to be 1.2-1.5 m/min. And constructing a mattress layer, wherein the mattress layer is used for coordinating the deformation of the piles and the soil between the piles, and the materials comprise medium coarse sand, broken stones and the like. The specific design form of the mattress layer comprises broken stones, medium coarse sand and geogrids from bottom to top. The maximum particle size of the gravel used in the mattress layer is not more than 25mm, 10-12% of stone powder or fine particles are mixed into the gravel, and the mixture is uniformly mixed and filled. Pebbles are not suitable for selection, the occlusion force of the pebbles is poor, and the thickness of the mattress layer is easy to be uneven due to construction disturbance. The sand adopted in the mattress layer is natural-graded medium-coarse sand and does not contain impurities such as grass roots, garbage and the like.
The CFG pile composite foundation at the construction and landfill section of the replacement and landfill alternate airport runway has not very high bearing capacity, generally not more than 200kpa, and the CFG pile composite foundation still has larger deformation because the improvement range of the compression modulus of the composite foundation is limited compared with that of a natural foundation. However, the CFG pile composite foundation has a high standard value of bearing capacity, has the properties of a rigid pile, and can well control settlement.
And thirdly, densely filling the junction of the two sections of the roadbeds by bentonite to enable the roadbeds of the excavation section and the landfill section to reach the same flat surface, and then constructing the airfield runway roadbed filling material.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.