JP2005248554A - Construction method of road grade separated crossing approach banking section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method of a road grade separated crossing approach banking section capable of quickly carrying out construction work of approach banking in a city section having severe restriction conditions in regard to a construction area. <P>SOLUTION: The method of constructing the approach banking section of the road grade crossing comprising the steps of constructing walls forming both sides of the road grade separated crossing approach section and making a banking between the walls comprises the steps of constructing the walling 1 by using pre-cast panels and placing aerated light-weight soil using excavated soil as the banking between the walling. The aerated light-weight soil is produced by conveying the muddy water-like original soil by a muddy water conveyance vehicle 11, conveying cement milk by a concrete mixer truck 12, and aerating mixing plants 4, 5, 6, 7, 8 and 10 including a bubble generating device set on the site and mixing the excavated soil, the cement milk and bubbles. When the aerated light-weight soil is produced, a regulation material is added in accordance with the content of the fine grain in the excavated soil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for constructing an approach embankment for a road intersection in an urban area.

  Traffic congestion in urban areas hinders logistics and has a significant adverse effect on economic activities. One way to eliminate traffic congestion is to create a three-dimensional intersection of a plane intersection road. Among them, the road crossing due to overpass is composed of a bridge part and approach embankment part.

  The approach embankment part of the road crossing by overpass is usually constructed by embankment supported by a retaining wall. Moreover, when aiming at weight reduction of embankment, it is also considered to use a bubble mixed lightweight soil.

  By the way, in the conventional method of constructing approach embankment with ordinary embankment, when the soft ground that is often found in urban areas is targeted, improvement of the foundation ground that supports embankment is required, so the construction period becomes longer, There was a problem that the traffic jam for a long time.

  As a solution to this problem, it is conceivable to use a bubble-mixed lightweight soil to reduce the weight of the embankment. However, if the content of fine particles in the raw material soil to be mixed (for example, local generated soil) increases, Since the property is impaired, there is a problem that the generated soil that can be used is limited.

  The present invention was devised in view of the above-mentioned problems, and proposes a construction method for a road three-dimensional intersection approach embankment that enables rapid construction of an approach embankment in an urban area with severe constraints on the construction area. As an objective.

The present invention is a method for constructing a road solid intersection approach embankment, and has the following configuration in order to solve the above-described technical problems.
That is, the construction method of the road level intersection approach embankment portion of the present invention,
In the method of constructing a wall material that forms both sides of the approach part of the road level intersection, and embedding between the wall materials to construct the approach level part of the road level intersection,
Building the wall material using a precast panel,
A bubble-mixed lightweight soil using locally generated soil as the embankment is placed between the wall materials.

  The bubble-mixed lightweight soil is a device that generates bubbles by carrying the generated soil in the form of muddy water in a muddy water truck and carrying cement milk (cement + water) in a mixer car. The generated soil, the cement milk, and the bubbles are mixed and generated using a bubble mixing plant including

  Moreover, when producing | generating the said bubble mixing lightweight soil, an adjustment material is added according to the fine grain part of the said generated soil. Blast furnace slag or fly ash is used as the adjusting material.

As described above, according to the present invention, according to the above configuration, the embankment can be reduced in weight as compared with a method of constructing with a normal embankment, and only a bubble mixing plant is installed on the site, and the material is a mud turbine. Since it is carried in with a mixer truck to produce bubble-mixed lightweight soil, the construction speed can be increased and rapid construction of approach embankment in urban areas with severe restrictions on the construction area becomes possible.

  Further, according to the present invention, a blending method for ensuring a predetermined quality as a bubble-mixed lightweight soil by adding an adjusting material such as blast furnace slag or fly ash according to the fine particle content of the generated soil to be used. Can be proposed. This makes it possible to construct a bubble-mixed lightweight embankment using generated soil with a high fine particle content, which has been difficult in the past.

The construction method of the road solid intersection approach embankment according to the best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings.
[Explanation of lightweight soil mixed with bubbles]
First, the bubble mixed lightweight soil used for a banking part is demonstrated.
The light-weight mixed soil is a mixture of raw material soil and cement, water and foaming agent to reduce weight, or a mixture of cement, water and foaming agent to reduce weight. Is.

  The raw soil can be used as purchased soil, sandy soil, construction surplus soil, etc., and cement is a stabilizer added to chemically stabilize the raw soil and air bubbles to give them strength and rigidity. It is. Water is a material used for diluting fluidity, lightness, or foaming agent in the mixed soil.

  The foaming agent is a material that generates bubbles for imparting light weight and fluidity to cement milk or mortar, and foams a dilute solution obtained by diluting the foaming agent at a predetermined dilution ratio to obtain bubbles. This foaming agent is a synthetic surfactant-type or protein-type foaming agent, which is a preform type (pre-foaming type).

Light-weight mixed soil is defined as a provisional compound capable of obtaining a wet density (raw specific gravity) of about 0.5 to 1.3 (g / cm ³ ) and is about 500 m without material separation by piping by pumping. In order to ensure the fluidity that can be pumped, it has a flow value of 180 mm.

In addition, the air-mixed lightweight soil can be blended with a uniaxial compressive strength (qu) of 294 KN / m ² (3 kgf / cm ² ) or more, but a typical embankment is 294 to 980 KN / m ² (3 kgf / A bubble-mixed lightweight soil having a uniaxial compressive strength of cm ^{2 to} 10 kgf / cm ² is used. Moreover, since it becomes independent after hardening, construction of vertical embankment is possible.

[Outline explanation of construction method of road level crossing approach embankment]
Next, based on FIG. 1, the outline of the construction method of the road solid intersection approach embankment part of the best form which concerns on this invention is demonstrated.

  First, as shown in the construction outline diagram of the construction method of the road solid intersection approach embankment part of FIG. 1, the wall material (composite panel) 1 is assembled around the place where the bubble mixed lightweight soil is placed.

  The wall material 1 is connected to the L-shaped steel 3 via an attachment fitting called an anchor separator 2. The L-shaped steel 3 is fixed to the ground. Therefore, the wall material 1 is stably fixed to the ground by being connected to the L-shaped steel 3.

  In addition, the wall material 1 is constructed by sequentially arranging panels having a size of about 30 cm × 90 cm, and a sealing material is applied between the wall materials to keep the water stop.

  Raw material soil such as generated soil, which is a material for the air-mixed lightweight soil, is made into muddy water and appropriately carried to the site by the mud turbine 11. Cement milk (cement + water) is also appropriately brought to the site by the concrete mixer truck 12. And the bubble mixed lightweight soil is placed using a bubble mixing plant installed on site. This bubble mixing plant includes a pressure pump 4, a foaming device 5, a generator 6, a bubble mixing device 7, a water tank 8, a kneading plant 10, and the like. The kneading plant 10 is a device for mixing the muddy water-like raw material soil (generated soil) and cement milk. Further, the foaming device 5 is a device that generates bubbles by using the introduced foaming agent. Furthermore, the bubble mixing device 7 is a device that further mixes bubbles with the generated soil and cement milk mixed to generate a bubble-mixed lightweight soil. The generated bubble-mixed lightweight soil is pumped and placed between the wall materials 1 by the pumping pump 4.

  This construction method eliminates the need for temporary storage of generated soil, cement silos, and the like, and enables construction of approach embankments in urban areas with severe restrictions on the construction area.

  Moreover, according to this construction method, the weight of embankment can be reduced to half or less compared with the conventional construction method which constructs a normal embankment by using a bubble mixed lightweight soil as a embankment material. As a result, when the soft ground often found in urban areas is targeted, the improvement of the foundation ground that supports the embankment, which was necessary in the conventional construction method, becomes unnecessary or can be reduced, leading to a shortened construction period.

  Furthermore, since the air-mixed soil lightweight soil used in this embodiment does not exert a large earth pressure on the side, the simple wall material 1 can be used, which also leads to a shortening of the construction period.

  Furthermore, an adjusting material such as blast furnace slag or fly ash is added according to the fine grain content of the generated soil used in this embodiment. By adding this adjusting material, it is possible to propose a blending method for ensuring a predetermined quality as a light-bubble mixed lightweight soil.

  That is, by adding the adjusting material, it is possible to prevent the fluidity from being remarkably lowered, thereby reducing the amount of water to be blended, and as a result, it is possible to ensure strength. In addition, this makes it possible to construct a bubble-mixed lightweight embankment using generated soil with a high fine grain content, which has been difficult in the past.

[Example 1]
Next, the model construction test which simulated the construction of the approach embankment part by the bubble mixed lightweight soil using generated soil implemented as Example 1 is demonstrated.
The test scale is a 2m x 2m x 1.8m high rectangular parallelepiped test piece assembled using the composite panel 1, and placed there for 2 consecutive days at a construction speed of 0.9m / day to dissipate the lateral earth pressure. The situation and the strength of the air-mixed lightweight soil after curing were confirmed.

Changes with time of the lateral earth pressure at four depths of the test body are as shown in FIG. That is, it was confirmed that the hydrostatic pressure (the target wet density ρ = 0.8 t / m ³ equivalent muddy water pressure) acts on the wall surface immediately after placement, but almost disappears after one day.

  FIG. 3 shows the uniaxial compressive strength after 28 days of construction, and FIG. 4 shows the corn index after 1 day of construction.

As for strength, the target uniaxial compressive strength of 1.5 N / mm ² that can ensure the performance of road embankment has been cleared after curing for 28 days (see Fig. 3), and the strength that allows the next construction even after 1 day of construction ( It was confirmed that the target cone index 0.5 N / mm ² ) was cleared (see FIG. 4).

[Example 2]
Next, as Example 2, an indoor blending test using fine particles of generated soil as parameters will be described. In this indoor blending test, the type and amount of the adjusting material to be added can be selected in accordance with the fine granule content, which is necessary for ensuring the predetermined quality as the bubble-mixed lightweight soil.

  FIG. 5 shows an image of a blending design chart that can be created based on an indoor blending test. 5A shows the case where Fc = 30%, and FIG. 5B shows the case where Fc = 50%. And according to this construction method, the blending design for clearing the target wet density and uniaxial compressive strength becomes possible by using the blending design chart shown in the figure.

It is a construction outline figure of the construction method of a road solid intersection approach embankment part. It is a figure which shows the time-dependent change of the side earth pressure in four depths of a test body. It is a figure which shows the uniaxial compressive strength after 28 days of construction. It is a figure which shows the corn index 1 day after construction. It is a figure which shows the image of the mixing | blending design chart which can be created based on an indoor mixing | blending test.

Explanation of symbols

1 Composite panel (wall material)
2 Anchor separator 3 L steel 4 Pressure pump 5 Foaming device 6 Generator 7 Bubble mixing device 8 Water tank 10 Kneading plant 11 Mud turbine 12 Concrete mixer truck

Claims (4)

In the method of constructing a wall material that forms both sides of the approach part of the road level intersection, and embedding between the wall materials to construct the approach level part of the road level intersection,
Building the wall material using a precast panel,
A method for constructing a road three-dimensional intersection approach embankment characterized in that a bubble-mixed lightweight soil using locally generated soil as the embankment is placed between the wall materials. The bubble mixed lightweight soil is
Bring the generated soil in the muddy state with a muddy wheel,
Cement milk is carried with a mixer truck,
The road three-dimensional intersection approach according to claim 1, wherein the generated soil, the cement milk, and the bubbles are mixed and generated using a bubble mixing plant that includes a device for generating bubbles that is installed in the field. Construction method for embankment. When producing the bubble mixed lightweight soil,
The construction method of the road solid intersection approach embankment part according to claim 1 or 2, wherein an adjusting material is added according to the fine grain portion of the generated soil.   The construction method for road multilevel approach approach embankment according to claim 3, wherein the adjusting material is blast furnace slag or fly ash.

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