JP2008088304A - Flowability suppression method for mud of high water content ratio and flowability suppressing agent used for this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate handling at transportation or the like by easily, safely and inexpensively reducing flowability of mud water or mud of a high water content ratio to an appropriate flowability in a short time. <P>SOLUTION: Any one or both of a predetermined amount of polyglutamic acid and a polyglutamic acid crosslinked substance is mixed into the mud of a high water content ratio as a flowability suppressing agent to reduce the flowability of the mud of a high water content ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly includes sewage with a high water content or soil discharged from sedimentation ponds of sewage treatment facilities, etc. discharged in connection with civil engineering work such as riverbeds, reclamation work, tunnel work, ground improvement work, etc. The fluidity of high water content sludge (hereinafter collectively referred to as mud) is suppressed or safely lost in a short time with a simple operation, and handling in transportation etc. is changed to an extremely easy one. The present invention relates to a method for suppressing fluidity of highly hydrous soil and a fluidity inhibitor used therefor.

  Mud that is discharged in large quantities from sites such as river dredging and ground improvement works is generally transported from the work site to a dumping site or treatment site using vehicles and ships, and if necessary, solidification processing etc. After being done, it is dumped or reused.

  By the way, the drained mud is not only a mud composed solely of soil containing a large amount of water, but also a mud containing various kinds of organic septics, and chemicals such as a soil improver introduced during construction. There are a wide variety of materials such as mud containing material. However, any mud is high in fluidity due to its high water content, and is extremely poor in handling in transportation.

  Therefore, in the discharge site of this kind of mud, generally, the drained mud is mixed with a water reducing agent (water absorbing agent), a solidifying agent, etc., and its properties are changed to gel or soft-cured. After that, he scoops it up with a power shovel and loads it on a transport vehicle.

  However, in the conventional method of suppressing the fluidity of the mud using a stabilizer mainly composed of a cement material, the mud after the treatment becomes alkaline due to the calcium content in the cement. Therefore, there is a drawback that it causes so-called secondary pollution.

For this reason, use of polymer water-absorbing agents, flocculants, hydrate forming agents such as hemihydrate gypsum and magnesium oxide, and gelling (solidifying) agents such as water glass grout agents, etc. A treatment method has been developed that suppresses the fluidity of mud while preventing water.
However, in each method, it is necessary to add a considerably large amount of the treatment agent, and it takes time to mix the treatment agent into the mud, and in addition, a considerable amount of time is required until the fluidity is lowered. And there is a problem that it is not economical.

JP 2003-82348 A Japanese Patent Laid-Open No. 10-102059 JP-A-5-320643

  The present invention relates to the problems as described above in the conventional method for suppressing fluidity of mud with a high water content ratio and fluidity inhibitor. The method of using a stabilizer mainly composed of cement material is that the soil after treatment becomes alkaline, causing secondary pollution, and b. Methods that use treatment agents such as water-absorbing agents, flocculants, hydrate-forming agents, and gelling agents require a large amount of treatment agents and require a long period of time to suppress fluidity. Solves problems such as chipping, penetrates well into mud without the need for special stirring or mixing operations, and mixes all kinds of fluidity inhibitors with a relatively small amount of fluidity inhibitor. It is an object of the present invention to provide a method for suppressing the fluidity of mud with a high water content and a fluidity inhibitor used therefor, which can reduce the fluidity of the mud within a very short time.

  In the present invention, a biodegradable and water-absorbing polymer that is harmless to human livestock is mixed into the mud so that the water in the mud is absorbed and fixed in the mud, thereby reducing the fluidity of the mud to the desired fluidity. According to the invention of claim 1, a predetermined amount of polyglutamic acid and / or cross-linked polyglutamic acid is mixed as a fluidity suppressant into mud with a high water content ratio, The basic structure of the invention is to reduce the fluidity of the mud.

  The invention of claim 2 is the invention according to claim 1, wherein polyglutamic acid having a weight 1/1000 to 5/1000 of the mud total weight Wo is mixed into the mud as a fluidity inhibitor. .

  The invention of claim 3 is the invention according to claim 1, wherein a polyglutamic acid cross-linked product having a weight of 1/10000 to 5/10000 of the mud total weight Wo is mixed into the mud as the fluidity inhibitor. It is.

  The invention of claim 4 is a fluidity inhibitor for mud with a high water content comprising either or both of powder or liquid polyglutamic acid and a cross-linked product of powder or liquid polyglutamic acid. This is a basic configuration of the invention.

  In the present invention, since the biodegradable polyglutamic acid and / or polyglutamic acid cross-linked product harmless to human livestock is mixed into the mud as a fluidity inhibitor, the mud after the fluidity is lowered is polluted. It is possible to safely control mud fluidity without causing any occurrence of environmental pollution or environmental pollution.

  In addition, it is possible to adsorb and fix the moisture in the mud within a short time and without the need for special mixing operations with the mixing of a very small amount of the fluidity suppressant. Moreover, it can be performed at a low cost.

  Furthermore, by increasing the amount of the fluidity inhibitor mixed, the mud can be gelled or solidified to a higher degree, and the fluidity of the mud can be arbitrarily adjusted by adjusting the amount of fluidity inhibitor mixed. Can do.

  As described above, the present invention can easily and quickly adjust the fluidity of mud discharged from a construction site, a riverbed site, etc., and can greatly facilitate the handling of the mud.

Next, an embodiment of the present invention will be described.
(Basic test 1)
First, the present inventors prepared 100 g of mud with a water content of 80 to 95 wt% (mud taken from a field for rice farming in Osaka Prefecture) in a petri dish, and 30 ml of water added thereto. At this time, the mud in the petri dish was in a state where the outer surface was just submerged. Next, 0.1 g, 0.2 g, 0.3 g and 0.4 g of polyglutamic acid were each used alone as a fluidity inhibitor. Then, the mixture was gradually mixed into the petri dish over about 60 seconds, and the change in the fluidity of the mud in the petri dish was observed and investigated.

  As a result, in the case of the mud for testing, that is, in the case of mud obtained by adding 30 ml of water to 100 g of mud with 80 to 95% water collected from the agricultural field, about 0.1 g of polyglutamic acid is added and mixed alone. Thus, after about 40 to 60 minutes, when water droplets on the surface of the mud in a wet state (just submerged) are not detected and its fluidity is lowered, and soaking with a spoon, the so-called mountain peak It was found that the fluidity was as good as it was.

(Basic test 2)
Similarly, a polyglutamic acid cross-linked product is used alone as a fluidity inhibitor, and 0.005 g, 0.01 g, 0.02 g, and 0.03 g of polyglutamic acid cross-linked product are the same as those used in the basic test 1. Each petri dish containing the test sample was gradually mixed for about 60 seconds, and the change in fluidity of the mud in the petri dish was observed and investigated.

  As a result, by mixing about 0.01 g of polyglutamic acid cross-linked product, water droplets on the surface of the mud under wet conditions (just submerged) are detected in about 1 to 2 minutes after mixing the entire amount of the water-absorbing agent. It was found that the fluidity was greatly reduced, and the fluidity was such that it could be easily squeezed in a heap when struck with a spoon.

  The polyglutamic acid used in the present invention, as shown in FIG. 2, is a polymer in which the γ-position carboxyl group and the amino group of the two carboxyl groups of the glutamic acid molecule are connected by an amide bond, It is synthesized by microorganisms belonging to the genus Bacillus such as Bacillus subtilis using glutamic acid as a raw material. In the present invention, polyglutamic acid manufactured by Nippon Polyglu Co., Ltd. (trade name: PGA-HM) is used.

  The polyglutamic acid cross-linked product is obtained by adding gamma rays to an aqueous solution of a natural polymer compound having a molecular weight of several thousands to several millions, which is formed by linear polymerization of glutamic acid called γ-polyglutamic acid having a structure as shown in FIG. It is assumed that it is a molecule having a network structure with a molecular weight of several tens of millions by causing a cross-linking reaction between the molecules of polyglutamic acid PGA-HM by irradiating, etc. ing. In the present invention, a polyglutamic acid cross-linked product manufactured by Nippon Polyglu Co., Ltd. (trade name PGA-CL) is used.

The polyglutamic acid crosslinked product PGA-CL itself has a structure as shown in FIG. Further, since not all of the polyglutamic acid PGA-HM is converted into a cross-linked product, the polyglutamic acid PGA-HM which is a starting material may be included in this in some cases.
This polyglutamic acid cross-linked product PGA-CL has a very high water retention capacity compared to polyglutamic acid PGA-HM, and the latter can hold water about 10 to 20 times its own weight. On the other hand, although depending on the conditions of the crosslinking reaction, the polyglutamic acid crosslinked product PGA-CL has the ability to retain water about 2000 times its own weight.

  Moreover, in the basic experiment, the change in fluidity when both polyglutamic acid and polyglutamic acid cross-linked product were mixed was not observed, but the fluidity was determined from the mixing ratio and total amount of both fluidity inhibitors. It can be easily estimated how much is suppressed.

  Table 1 shows the results of investigating the relationship between the elapsed time after mixing of the fluidity inhibitor in the basic experiment and the weight of the mud, the No1 column does not contain the fluidity inhibitor, and the No2 column is The column with No. 3 added with 0.25 g of polyglutamic acid and the column No. 3 show the weights of those with 0.015 g of a crosslinked polyglutamic acid.

From the basic test, it was found that there was no significant difference in weight change whether or not the treatment for suppressing fluidity was performed. However, there is a large difference in the situation after mixing the fluidity inhibitor, and in the case of polyglutamic acid, a considerably large amount of administration was required, whereas in the case of a polyglutamic acid cross-linked product, 0.01% was required. It can be presumed that the addition of ~ 0.02 g is effective, and since a gel-like lump is seen, the effect can be obtained even with a smaller amount. In addition, the polyglutamic acid cross-linked product had an immediate effect, and almost no water was seen in 1 to 2 minutes after mixing.
Regarding the strength, it was considered that the case of polyglutamic acid was the most solidified state, and it was found that the degree of solidification was higher than that of the cross-linked polyglutamic acid.

  In addition, from the result of the basic test, as described later, when a polyglutamic acid cross-linked product is used, it varies depending on the object, but from a wet mud with about 100 to 200 ppm in a weight ratio. It was found that it was possible to absorb moisture and suppress fluidity. Further, when polyglutamic acid is used, it is necessary to input about 1000 to 2000 ppm, but it has been found that the polyglutamic acid is hardened and solidified by being more uniformly diffused into the mud.

  That is, through each of the basic experiments 1 and 2, the inventors of the present application use polyglutamic acid as a fluidity inhibitor even in mud having a water content of 80 to 95% (wt%) or more. When 0.1 to 0.2 g (about 1000 to 2000 ppm) of polyglutamic acid is mixed with 100 g of mud in weight ratio, and when polyglutamic acid cross-linked product is used as a fluidity inhibitor, By mixing 0.01 to 0.02 g (100 to 200 ppm) of a polyglutamic acid crosslinked product with 100 g of mud, within about 0.5 to 1 hour in the case of polyglutamic acid and 2 to 2 in the case of a polyglutamic acid crosslinked product. Within 10 minutes, it has been found that the fluidity can be reduced to a state where no water droplets are seen on the surface and can be scooped up with a spoon.

The present invention was developed based on the basic test as described above, and an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing a case where the present invention is applied to sewage (mud) discharged during construction work of a foundation pile and its fluidity is suppressed. In FIG. 2 is an earth auger, 3 is an excavation hole, 4 is a casing, 5 is an injection pipe, 6 is a swivel joint, 7 is a discharge pipe, 8 is muddy water (mud), 9 is a sewage receiving tank, 10 is a fluidity inhibitor tank, 11 is a fluidity inhibitor, 12 is a stirrer, and 13 is treated waste soil.

  Referring to FIG. 1, a casing 4 is press-fitted while forming an excavation hole 3 in the soil using an earth auger 2 held by a pile driving machine 1, and then reinforcing bars and cement mortar are injected into the casing 4. When a foundation pile is formed, a large amount of water is ejected from the tip of the earth auger 2 into the excavation hole 3 when the excavation hole 3 is drilled, and mud ( Mud) 8 is discharged to the ground.

In the present invention, the discharged muddy water (mud) 8 is stored in the sewage receiving tank 9, and when a certain amount of muddy water 8 is stored in the receiving tank 9, the receiving tank 9 that receives the muddy water 8 is used as another receiving tank. Switch to 9.
Then, a predetermined amount of the fluidity inhibitor 11 is mixed from the fluidity inhibitor tank 10 into the receiving tank 9 in which a certain amount of muddy water 8 is stored, and this is lightly stirred by the stirrer 12.

  The fluidity suppressing agent 11 is normally stored in an aqueous solution state in the tank 10 in advance, but may be stored in the form of powder.

  Moreover, the stirring operation by the stirrer 12 is not necessarily required, and the fluidity inhibitor 11 is stirred or dispersed relatively quickly into the sewage 8 simply by evenly spraying the fluidity inhibitor 11 into the sewage receiving tank 9. Go mixed.

  The mixing amount of the fluidity inhibitor 11 is set in advance by the control valve 14. When processing mud (mud) 8 having a normal water content ratio of about 80 to 95 wt%, the weight Wo of the mud 8 is 100 g. On the other hand, when the fluidity inhibitor 11 is polyglutamic acid, Wp = 0.1 to 0.5 g of polyglutamic acid (that is, weight ratio Wp / Wo = 1 to 5/1000) and fluidity inhibition When the agent 11 is a polyglutamic acid crosslinked product, Wp ′ = 0.01 to 0.05 g (that is, weight ratio Wp ′ / Wo = 1 to 5/10000) is added.

  When the flow control agent 11 comprising the polyglutamic acid or the polyglutamic acid cross-linked product is added and mixed, the polyglutamic acid is added after about 30 to 40 minutes, and the polyglutamic acid cross-linked product is added about 2 to 5 minutes. Later, the moisture in the mud 8 is adsorbed (absorbed) to the fluidity inhibitor 11 so that the moisture cannot be seen on the upper outer surface of the mud in the receiving tank 9. The fluidity is lowered to such an extent that it can be piled up without dropping.

As a result, even when the mud 13 that has been subjected to the fluidity suppression treatment in the sewage receiving tank 9 is transported with a power shovel or the like, no mud water is dissipated and the mud 13 is extremely easy to handle. It becomes.
Moreover, even when loaded on the platform of the transport vehicle, the loaded state is almost the same as when transporting relatively sandy river sand, and the muddy water 8 can be handled very easily.

  In addition, in the present Example, although the fluidity | liquidity suppression process of the mud (sewage) 8 discharged | emitted at the time of formation of the foundation pile by what is called on-site driving | operation was described, the property and kind of the mud 8 which is a process target, its generation | occurrence | production location Is completely unrelated to the application of the present invention, and the present invention can be implemented anywhere as long as the fluidity inhibitor 11 can be mixed or charged into the mud 8. However, the fluidity of mud can be suppressed.

  The present invention can be applied without questioning the origin of sewage (muddy soil) if it is a mixture of soil components and water, and not only in the field of civil engineering / architecture, but also in livestock, agriculture, forestry, etc. It can also be used in the field.

It is explanatory drawing which shows the Example of this invention. 1 is a structural diagram of polyglutamic acid (PGA-HM) used as a water absorbing agent in the present invention. 1 is a structural diagram of a crosslinked polyglutamic acid (PGA-LC) used as a water absorbing agent in the present invention.

Explanation of symbols

1 is a pile driver 2 is an earth auger 3 is an excavation hole 4 is a casing 5 is an injection pipe 6 is a swivel joint 7 is a discharge pipe 8 is muddy water (mud)
9 is a muddy water receiving tank 10 is a fluidity inhibitor tank 11 is a fluidity inhibitor 12 is a stirrer 13 is a treated waste soil 14 is a control valve

Claims (4)

  A high water content mud is mixed with either or both of a predetermined amount of polyglutamic acid and a polyglutamic acid cross-linked product as a fluidity inhibitor to reduce the fluidity of the high water content mud. Method for suppressing fluidity of mud with water content.   The method for suppressing fluidity of mud with a high water content according to claim 1, wherein polyglutamic acid having a weight of 1/1000 to 5/1000 of the mud total weight Wo is mixed into the mud as the fluidity inhibitor.   The fluidity control of mud with high water content according to claim 1, wherein a polyglutamic acid cross-linked product having a weight of 1/10000 to 5/10000 of the mud total weight Wo is mixed into the mud as the fluidity inhibitor. Method.   A fluidity inhibitor for mud with a high water content, comprising either or both of powder or liquid polyglutamic acid and a crosslinked product of powder or liquid polyglutamic acid.

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