JP2011106158A - Compacting sand-pile creating device and compacting sand-pile creating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compacting sand-pile creating device which uses fluidized sand pile material in a conventional compacting sand-pile creating device, and to provide a compacting sand-pile creating method. <P>SOLUTION: The compacting sand-pile creating device includes a sand-pile material fluidizing plant, a sand-pile creating hollow pipe, a mixer built-in hopper at the upper part of the hollow pipe, a pressure pump for sending the fluidized sand pile material under pressure produced in the sand-pile material fluidizing plant into the hopper, a fluidized material supply pipe for connecting the pressure pump with the hopper, and a plasticizing agent supply pipe for connecting a plasticizing agent supply device with the hopper. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a compacted sand pile construction device and a compacted sand pile construction method for strengthening the ground by creating a large number of expanded sand piles compacted in the ground at an appropriate pitch.

  JP-A-2008-285810 discloses a sand pile material fluidization plant, a hollow pipe for sand pile formation, and the sand pile material fluidized product produced in the sand pile material fluidization plant. A sand pile comprising: a pressure-feeding pump to be sent to a fluidized material; a fluidized material supply pipe for connecting the pressure-feed pump and the hollow pipe; and a plasticizer supply pipe for connecting the plasticizer supply device and the hollow pipe. In the process of adding a fluidizing agent to the sand pile material used for equipment and ground improvement, and injecting the fluidized ground improvement material into the ground, a plasticizing agent is added and a sand pile is created with the plasticized ground improvement material. Sand pile construction methods are each disclosed. JP 2008-285810 A uses a mixer that mixes a sand pile material fluidized material and a plasticizer in the vicinity of the hollow tube, and further stores the fluidized material in a moving bucket above the hollow tube. It is disclosed that a plasticizing agent is added to form a sand pile.

  According to the sand pile creation device and the sand pile creation method disclosed in Japanese Patent Application Laid-Open No. 2008-285810, even in a narrow sand pile creation area where the sand pile material supply means cannot be secured, such as directly below or near an existing structure. Sand piles can be created.

JP 2008-285810 A (Claims 1 and 4)

  However, in the sand pile creation device and sand pile creation method disclosed in Japanese Patent Application Laid-Open No. 2008-285810, the sand pile material fluidized material and the plasticizer are mixed to become a plasticized sand pile material that passes through the hollow pipe. In the middle of, or just out of the hollow tube, not in the hopper. This is because the sand pile material fluidized material and the plasticizer are separately sent and mixed, so the mixed state tends to be uneven, and in fact, the compacted sand pile creation device cannot be used. It was a thing.

  That is, an object of the present invention is to provide a compacted sand pile creation device and a compacted sand pile creation method that enable use of a fluidized material of sand pile material in a conventional compacted sand pile creation device.

  In such a situation, the present inventors have intensively studied, and as a result, in the hopper of the compacted sand pile forming device, the sand pile material fluidized material and the plasticizer are mixed until the sand pile material becomes plastic, The present invention was completed by finding that a compacted sand pile construction apparatus that does not require a moving bucket to the upper part of the hollow tube can be used by returning to the sand pile material that has been made, that is, the sand pile material before fluidization.

  That is, the present invention includes a sand pile material fluidizing plant, a sand pipe forming hollow pipe, a hopper with a built-in mixer above the hollow pipe, and the sand produced by the sand pile material fluidizing plant. A pressure feed pump that sends the pile material fluidized material to the hopper, a fluidized material supply pipe that connects the pressure feed pump and the hopper, and a plasticizer supply pipe that connects the plasticizer supply device and the hopper. A compacted sand pile construction device is provided.

  Further, the present invention adds a fluidizing agent to the sand pile material used for ground improvement, mixes the fluidized ground improving material and plasticizing agent in the hopper above the hollow tube, and plasticizes the ground improving material, The present invention provides a compacted sand pile construction method in which a plastic pile of ground improvement material is passed through a hollow tube to create a sand pile.

  In addition, the present invention is manufactured by the I process for sending the sand pile material fluidized material produced at the sand pile material fluidizing plant to the hopper of the sand pile building construction machine through the piping by the pressure feed pump, and the plasticizer supply device. II step of sending the plasticizer to the hopper, III step of mixing the sand pile material fluidized material and the plasticizer to plasticize the sand pile material fluidized material in the hopper, and An IV process for compacting sand pile material into the ground, and a compacted sand pile construction method is provided.

  According to the present invention, the fluidized material of the sand pile material can be compacted and sent into the hopper of the sand pile forming device using a general-purpose liquid feed pump. Then, in the hopper, the sand pile material fluidized material and the plasticizer are mixed until the sand pile material is plasticized, and the plasticized sand pile material, that is, the sand pile material returned to the sand pile material before fluidization is returned. Can be placed in a hollow tube. For this reason, the utilization of the compacting sand pile formation apparatus using the sand pile material fluidized material which does not require the movement bucket to a hollow pipe upper part is attained.

It is the schematic of a compacted sand pile production apparatus. (A) is a schematic diagram explaining fluidization of sand pile material, (B) is a schematic diagram explaining plasticization of sand pile material.

  Next, an example of a compacted sand pile construction method and a compacted sand pile construction device (hereinafter also simply referred to as “sand pile construction method and sand pile creation device”) in the embodiment of the present invention is shown in FIGS. 1 and 2. Fig. 1 is a schematic diagram of a sand pile forming device, Fig. 2 (A) is a schematic diagram illustrating fluidization of sand pile material, and (B) is a schematic diagram illustrating plasticization of sand pile material. It is.

  The sand pile forming device 50 is manufactured by the sand pile material fluidizing plant 10, the hollow pipe 23 for sand pile forming, the hopper 27 with a built-in mixer at the upper part of the hollow tube, and the sand pile material fluidizing plant 10. Pressure feed pump 4 for feeding the sand pile material fluidized material to the hopper 27, fluidized material supply pipe 34 connecting the pressure feed pump 4 and the hopper 27, and plasticizer supply for connecting the plasticizer supply device 5 and the hopper 27. A pipe 35 is provided.

  The sand pile material fluidization plant 10 is located in a place away from the sand pile formation area 26, and is a group of devices for producing a sand pile material fluidized product. The sand pile material fluidization plant 10 includes, for example, a sand pile material fluidized material supply means 1, a sand pile material supply means 2, a fluidizer supply means 3, a sand pile material transfer pipe 31, a fluidizer transfer pipe 32, and a sand pile material. It consists of a fluidized material transfer pipe 33. In addition, a storage tank, a supply pump, etc. are installed in each supply means as needed. Moreover, you may install a flow meter in each piping of the sand pile material transfer piping 31, the fluidizer transfer piping 32, and the sand pile material fluidization material transfer piping 33. Such a sand pile material fluidization plant 10 does not need to be installed in the sand pile creation area 26, and it is not necessary to secure an installation space for creating a sand pile directly under or near an existing structure. Is preferred. As the fluidized material supply pipe 34, a flexible hose is usually used, and its length is appropriately determined, but is generally 10 m or more and less than 200 m.

  The sand pile material may be a known material that has been used in the conventional sand pile construction method, and examples thereof include sand, sand containing silt and gravel, crushed stone, and slag. The sand pile material preferably has a maximum particle size of 10 mm or less, more preferably a content of 10 mm or less in the particle size of 1 mm or less, and a content of 15% or less in the content of 0.075 mm or less (fine particles). , Preferably 10% or less. If the maximum particle size of the sand pile material exceeds 10 mm, the sand pile material having a large particle size is clogged in the pump or the pipe, and there is a problem in the pumping of the fluidized material. On the other hand, if the content of fine particles is too large, a sand pile that is sufficiently compacted cannot be formed, so that the ground improvement effect cannot be obtained.

  The sand pile material fluidization plant 10 is not limited to the above-mentioned form. For example, the sand pile material fluidized material supply means 1 and the sand pile material fluidized material transfer pipe 33 are omitted, and the sand pile material transfer pipe 31 is directly pumped. 4, and a fluidizing agent transfer pipe 32 may be connected to the sand pile material transfer pipe 31. Thereby, sand pile material and a fluidizing agent can be mixed in piping. In addition, in the production of the sand pile material fluidized product, if additional water is required, a separate water supply means may be installed.

  A well-known thing can be used for the pressure pump 4, For example, a piston pump, a squeeze pump, etc. are mentioned.

  The hollow pipe 23 for sand pile formation is attached to a known ground improvement machine 20. Examples of the ground improvement machine 20 include an apparatus that implements a conventional compacted sand pile construction method. As an apparatus for carrying out the compacting sand pile construction method, for example, the hollow pipe 23 is penetrated by a rotary press-fitting work by a forced lifting device 22 using a rack and a pinion attached to the upper part of the leader 24 as shown in FIG. And an apparatus for performing a static compaction sand pile method for performing drawing, and an apparatus for performing a reversible sand compaction method that uses a vibrating hollow tube and repeats penetration, withdrawal and retraction.

  The hopper 27 is installed on the upper portion of the hollow tube 23, and a hopper of a conventional compacted sand pile forming device may be used. The hopper 27 has a built-in mixer (not shown). Examples of the mixer include a paddle mixer. When using the hopper of the conventional compacted sand pile forming device, a new mixer may be attached. Moreover, the mixer is preferably provided with a rotational resistance measuring device for measuring an increase in rotational resistance value of the mixer, for example. When the sand pile material fluidized material and the plasticizer are mixed in the hopper 27 and the sand pile material fluidized material plasticizes and returns to the sand pile material, the rotational resistance increases. Can be determined.

  The plasticizer supply device 5 usually has a plasticizer storage tank and a plasticizer supply pump, and a flow meter or the like is appropriately installed. The plasticizer supply device 5 is installed in the vicinity of the sand pile formation area 26 or in a place away from the sand pile formation area 26, but preferably installed in a place away from the sand pile formation area 26 directly below the existing structure. Or it is suitable at the point which does not need to ensure the installation space at the time of constructing a sand pile recently.

  In the sand pile forming device 50, the tip of the fluidized product supply pipe 34 may be connected to any part of the hopper 27, and is an upper opening of the hopper 27 in FIG. 1. Further, the tip of the plasticizer supply pipe 35 may be connected to any part of the hopper 27, and is an upper opening of the hopper 27 in FIG. 1.

  Next, the sand pile construction method will be described. In the sand pile construction method of the present invention, a fluidizing agent is added to the sand pile material used for ground improvement, and the fluidized ground improvement material and plasticizing agent are mixed in the hopper at the top of the hollow tube to obtain the ground improvement material. It is a construction method in which a sand pile is created by passing plasticized ground improvement material through a hollow tube. The sand pile material fluidized product includes a sand pile material and a fluidizing agent. The sand pile material is the same as that described in the sand pile forming device.

  The fluidizing agent makes the sand pile material easier to flow or pipe transport. When the fluidizing agent is not blended, clogging occurs in the piping, and the pipe cannot be transported. Examples of the fluidizing agent include a water-absorbing polymer and a polymer agent. A fluidizing agent can be used combining these 1 type (s) or 2 or more types.

  Examples of the water-absorbing polymer include sodium acrylate polymer partially crosslinked products and sodium acrylate polymer crosslinked products. Of these, sodium acrylate polymer partially crosslinked products are preferred.

  Examples of the polymer agent include nonionic polymer agents, anionic polymer agents, cationic polymer agents, and amphoteric polymer agents. Examples of the nonionic polymer agent include polyacrylamide. Examples of the anionic polymer agent include homopolymers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamide 2-methylpropane sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, and copolymers with acrylamide. . Examples of the cationic polymer agent include a copolymer of acrylamide and N, N-dimethylaminoethyl methacrylate or a system N, N-dimethylaminoethyl acrylate monomer. The polymer agent can be used in either powder or liquid form. As the polymer agent, either a natural product or a synthetic product can be used, but it is preferable to use a synthetic product in that a fluidized product can be obtained with a small amount. These polymer agents can be produced by a known method described in Japanese Patent Publication No. 34-10644.

  A preferred polymer agent has a molecular weight of 1 million or more, preferably 2 million or more and 10 million or less, and a water-in-oil type having a dispersed particle diameter of 100 μm or less made of an acrylic polymer having an ionization degree of 0 to 100 mol%. It is in the form of an emulsion.

  The blending ratio of the fluidizing agent is appropriately determined, but is usually 0.01 to 10.0% by weight, preferably 0.1 to 1.0% by weight, based on the sand pile material. . When the fluidizing agent is diluted with water, the sand pile material can be fluidized without adding additional water. For example, in the case of a 6.4% concentration fluidizing agent diluted with water, the blending ratio is preferably 1.6 to 16% by weight with respect to the sand pile material. If the blending ratio of the fluidizing agent is too small, the sand pile material will not be fluidized and will not be transported due to separation or clogging in the piping. Moreover, even if there are too many compounding ratios of a fluidizing agent, the fluidization effect does not change, but it raises cost on the contrary. The sand pile material fluidized product may contain, for example, water, a fluidization accelerator and the like in addition to the above essential components.

  The fluidity that can be transported by a pipe with a pressure pump means that the flow value in the “air mortar and air milk test method” 1.2 cylinder method specified by the Japan Highway Public Corporation Standard (JHS A 313-1992) is 100 mm or more. . The cylinder method refers to the following method. A cylinder having an inner diameter of 80 mm and a height of 80 mm is placed on a horizontal plate, and the sample is gently put to the upper end so as not to overflow the cylinder, and the surface of the sample is made to coincide with the upper end of the cylinder. Thereafter, the cylinder is pulled up vertically, the diameter of the sample spread is measured, and displayed as a flow value mm.

  In addition to the “cylinder method”, the sand pile material fluidized product can also be grasped by hand and judged from the experience. That is, when the sand pile material fluidized product is grasped by hand, it is not compacted, does not separate, has a muddy feeling, and does not remain in the hand is a suitable fluidized product. As shown in FIG. 2A, fluidization is thought to increase fluidity because the fluidizing agent 42 retains water and the internal friction is reduced by maintaining the interparticle distance of the sand 41.

  Examples of the plasticizer include cationic synthetic polymer agents, polyaluminum chloride, calcium chloride, aluminum sulfate, ferric chloride, and aluminum hydroxide. As the plasticizing agent, either powder or liquid can be used. Examples of the cationic synthetic polymer include polycondensates of ammonia, aliphatic alkyl mono or diamine or polyamine and epihalohydrin. Examples of the alkyl monoamine include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, n-butylamine, and isobutylamine. Examples of the diamine or polyamine include aminoethyl-methylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, hexamethylenediamine and the like. Examples of epihalohydrins include epichlorohydrin and epibromohydrin.

  The amount of plasticizer used is a blending amount capable of plasticizing the fluidized material, and is determined as appropriate. Specifically, it is 0.001 to 10 by weight ratio blending with respect to the sand pile material in the fluidized material. % By weight, preferably 0.01 to 1.0% by weight. If the plasticizer is added too little, the fluidized material will not be plasticized and compacted, making it impossible to create a sand pile as designed. Moreover, when there is too much addition of a plasticizer, cost will be raised. As shown in FIG. 2 (B), the plasticizing is performed by discharging the water that has been retained by decomposing the molecular bonds when the fluidizing agent 42 comes into contact with the plasticizing agent. Return to. The plasticity in which the plasticizing agent and the fluidizing agent react with each other and the sand pile material returns to the original grain size is called chemical plasticization. Hereinafter, plasticization refers to chemical plasticization.

  Judgment of plasticization can be made by a rotational resistance measuring device installed in the mixer. Plasticization is determined by the wet density of the sand pile after the sand pile has been created. Actually, however, the primary judgment is made by a soil test, and then the rotation of the mixer is performed by a laboratory simulation using a mixer. Secondary determination by resistance value. The soil test is to measure the wet density of the sample prepared by the sample preparation method of “Soil compaction test by tamping” specified in Japanese Industrial Standard (JIS A 1210: 1999). Compared with the result (wet density) obtained by compacting the hydrated sand (raw sand), the wet density shows a recovery rate of 90% or more, preferably 95% or more. Note that fluidized sand that has not been plasticized cannot be solidified, and the rammer reaches the bottom of the mold. Even from this, plasticization can be determined. That is, the rotational resistance value (R1) when the fluidized material is mixed with the mixer is measured, and then the rotational resistance value (R2) when the plasticized material recovered to the above value in the soil test is mixed with the mixer is measured. These data may be input to the rotational resistance measuring device, and a signal may be generated when the rotational resistance value changes from R1 to R2.

  Next, a sand pile is created with the plasticized ground improvement material. This sand pile construction method is the same as a known compaction sand pile construction method such as a static compaction sand pile construction method or a back-up type sand compaction construction method.

  In addition, the sand pile construction method of the present invention includes an I process of sending a sand pile material fluidized material produced in a sand pile material fluidization plant to a hopper of a sand pile construction machine through a pipe by a pressure pump, and a plasticizer. II step of sending the plasticizer produced by the feeder to the hopper, III step of mixing the sand pile material fluidized product and the plasticizer to plasticize the sand pile material in the hopper, And IV process for compacting the plasticized pile material into the ground. Usually, the steps I to IV are continued in this order, but the order in which the steps I and II are performed may be reversed.

  In the I-stage sand pile material fluidization plant, it is preferable to preliminarily determine the blending ratio of the sand pile material and the fluidizing agent and to supply them continuously to the pump. Such sand pile material fluidized material is sent to the hopper by pipe transportation. Thereby, the transfer from a distant place is attained and the installation in the vicinity of the existing structure can be reduced in size.

  In the plasticizer supply apparatus in step II, a method is preferable in which the blending ratio of the plasticizer to the sand pile material is determined in advance by preliminary experiments and continuously supplied to the pressure pump. Such a plasticizer is sent to the hopper by pipe transportation. Thereby, the transfer from a distant place is attained and the installation in the vicinity of the existing structure can be reduced in size.

  In step III, the sand pile material fluidized material and the plasticizer are mixed in the hopper, and the sand pile material fluidized material is plasticized in the hopper. The time from the mixing of the sand pile material fluidized material and the plasticizer to the plasticization of the sand pile material fluidized material cannot be determined unconditionally depending on the type and amount of the plasticizer. 30 seconds to 2 minutes. After the step III, the sand pile material before fluidization exists in the hopper.

  The IV process is a process of compacting the plasticized sand pile material into the ground. This step is the same as that described in the step of creating a sand pile with the plasticized ground improvement material, and the description thereof is omitted.

  The plasticized sand pile material contains separated water, a fluidizing agent and a plasticizing agent. Of these, water is brought into the ground, but after sand pile construction, it evaporates in the ground due to capillary action. Further, although the fluidizing agent and the plasticizing agent are present in the sand pile, they are in a small amount and do not adversely affect the strength of the sand pile and do not pollute the environment.

  According to the compacted sand pile construction method and the compacted sand pile creation device of the present invention, the existing compacted sand pile creation device can be used, and the sand pile material can be supplied to the hopper with a general-purpose liquid feed pump. A moving bucket to the upper part of the hollow tube becomes unnecessary, the sand pile forming device is simplified, and the construction cost can be suppressed.

  Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.

Reference example 1
(Manufacture of sand pile material fluidized material)
Water-in-oil emulsion with 30% water added to the dry river sand (sand pile material) with a particle size of 0.07 to 2.0mm in a weight ratio with respect to the sand pile material, and an anionization degree of 10 mol% Nonionic polyacrylamide in the form (concentration 6.4%) "Himoloc V-310" (manufactured by Hymo Co., Ltd.) (fluidizing agent A) is added to the sand pile material by 5.0% by weight ratio, A sand pile material fluidized material was produced. In addition, this compounding quantity is 0.32 weight% in nonionic polyacrylamide density | concentration.

(Evaluation of fluidized material of sand pile material)
The fluidity of the fluid obtained by the above production method was evaluated by a cylinder method and a grip test. The results of the cylinder method are shown in Table 1. Further, in the grip test, it was a good result that it did not compact, did not separate, had a muddy feeling, and did not remain in the hand.

Reference example 2
It replaced with the 0.32 weight% mixing | blending of the fluidizing agent A, and it carried out by the method similar to the reference example 1 except not having blended the fluidizing agent A of Table 1. Moreover, the sand pile material fluidized material was evaluated by the same method as in Reference Example 1. The results of the cylinder method are shown in Table 1.

  In Reference Example 1, the flow value in the cylinder method was 100 mm or more, and the fluidity was excellent.

Reference example 3
A plasticizer solution is added to the fluidized material of Reference Example 1 by 9.075% (weight ratio) with respect to the sand pile material, and mixed at a rotation speed of 284 revolutions per minute using a paddle mixer. Obtained. The plasticizer solution is 0.55% (weight ratio) of polyaluminum chloride and 0.275% (weight ratio) of cationic synthetic polymer agent (quaternary salt of dimethylamine / epichlorohydrin polycondensation), Dissolved in water. The following soil test was carried out on this plasticized material. The results are shown in Table 2. The time until plasticization after mixing the fluidized material and the plasticizer solution was 30 seconds. Plasticization was performed by observing changes in the rotational resistance of the paddle mixer.

Reference example 4
The following soil test was conducted on the fluidized material of Reference Example 1. The results are shown in Table 2.
That is, the fluidized material of Reference Example 1 does not add a plasticizer solution.

Reference Example 5
The following soil test was conducted on the sand pile material of Reference Example 1. The results are shown in Table 2. That is, in Reference Example 5, the sand pile material of Reference Example 1 is raw sand.

(Soil test)
The wet density of the sample prepared by the sample preparation method of the soil compaction test method (JIS A1210) by tamping is measured. In the sample preparation method of the compaction test, a plasticized material (sample) placed in a cylindrical container is tamped under a predetermined condition to obtain a compacted body. For example, in the case of the method A, a 2.5 kg mass of a rammer is used, a 30 cm height from each tamped surface and a 10 cm mold, the number of tamped layers is 3 times, and the number of tamped times per layer is 25 times. Do the tamping. The wet density of the ground soil is obtained from a predetermined calculation formula.

  The plasticized material of Reference Example 3 had a recovery rate of 101% and was suitable as a sand pile material. Therefore, by obtaining such a plasticized material of the sand pile material fluidized material in the hopper of the compacted sand pile creation device, the conventional compacted sand pile can be created and the compacted sand pile can be created.

DESCRIPTION OF SYMBOLS 1 Sand pile material fluidized material supply means 2 Sand pile material supply means 3 Fluidizer supply means 4 Pressure feed pump 5 Plasticizer supply apparatus 10 Sand pile material fluidization plant 20 Ground improvement machine 23 Hollow pipe 24 for sand pile formation Leader 26 Sand pile formation area 27 Hopper 31 Sand pile material transfer pipe 32 Fluidizer transfer pipe 33 Sand pile material fluidized substance transfer pipe 34 Fluidized substance supply pipe 35 Plasticizer supply pipe 50 Sand pile generator

Claims (4)

A sand pile material fluidization plant;
A hollow pipe for sand pile construction,
A hopper with a built-in mixer at the top of the hollow tube;
A pressure-feed pump that sends the sand pile material fluidized product produced in the sand pile material fluidization plant to the hopper;
A fluidized material supply pipe connecting the pressure pump and the hopper;
A plasticizer supply pipe connecting the plasticizer supply device and the hopper;
A compacted sand pile forming device characterized by comprising:   A fluidizing agent is added to the sand pile material used for ground improvement, and the fluidized ground improvement material and plasticizing agent are mixed in the hopper at the top of the hollow tube to plasticize the ground improvement material and plasticize it. A compacted sand pile construction method, characterized in that a sand pile is created by passing the material through a hollow tube. I process for sending the sand pile material fluidized material produced in the sand pile material fluidization plant to the hopper of the sand pile construction machine through piping by a pressure feed pump;
II step of sending the plasticizer produced by the plasticizer supply device to the hopper;
Mixing the sand pile material fluidized material and the plasticizer to plasticize the sand pile material fluidized material in the hopper;
A compacted sand pile construction method comprising: an IV step of compacting the plasticized sand pile material into the ground.   4. The compacted sand pile construction method according to claim 2, wherein the sand pile material fluidized material includes a sand pile material and a fluidizing agent.

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