Fluidized sand and method of density control

Abstract

A fluidized sand composition for use as a filling material for sinkholes and the like weakened ground cavities. The fluidized sand composition is produced by mixing graded sand, water, a fluidizer, a plasticizer, and a surface active agent. The fluidized sand composition is easily injected into the ground cavity of a sinkhole. After filling, the fluidized sand composition will return to the solid natural condition according to the effect of plasticizer previously added. The fluidized sand composition allows for compaction, soil stabilization, permits water migration through the material, and can be easily excavated.

Claims

1. A fluidized composition for soil stability and water migration in a cavity comprising: adding a quantity of water to sand forming fluidized sand; admixing about 9.1 kg/m.sup.3 anionic polymer for each 1 m.sup.3 of fluidized sand; admixing about 0.7 kg/m.sup.3 cationic polymer plasticizer for each 1 m.sup.3 of fluidized sand; admixing about 0.7 kg/m.sup.3 of a surface active agent for each 1 m.sup.3 forming a fluidized composition; measuring the density of said fluidized composition; injecting said fluidized composition into a cavity; sampling said injected fluidized composition by use of a Standard Penetration test; measuring the density of said sampling; wherein said injected fluidized composition having a constancy of volume and constancy of density to provide soil stability and water migration.

2. The fluidized composition according to claim 1 wherein said anionic polymer consists of polyacrylamide and sodium polyacrylate.

3. The fluidized composition according to claim 1 wherein said cationic polymer plasticizer consists of polyethylene, polyamine, dimethylamine, and epichlorohydrin.

4. The fluidized composition according to claim 1 wherein the sand is graded and obtained from an area local to the cavity.

5. The fluidized composition according to claim 1 including the step of adding a fluidity keeper, wherein the fluidity keeper extends the fluidity duration of the fluidized sand.

6. The fluidized composition according to claim 2 wherein said polyacrylamide is defined as: ##STR00007## and said sodium polyacrylate defined as: ##STR00008##

7. The fluidized composition according to claim 3 wherein said polyethylene is defined as: ##STR00009## polyamine is defined as: ##STR00010## Dimethylamine is defined as: ##STR00011## and Epichlorohydrin is defined as: ##STR00012##

8. The fluidized composition according to claim 1 wherein the unit weight of said fluidized sand can be altered by the amount of plasticizer added and the duration of mixing/vibration.

9. The fluidized composition according to claim 1 wherein said surface agent is non-ionic.

10. The fluidized composition according to claim 9 wherein said surface agent is selected from the group consisting of: diethanolamide; polyoxyethylene alkyl ether; or polyoxypropylene blockpolymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a chart of controllable unit weight through dosage;

[0035] FIG. 2 is a chart of controllable unit weight through mixing—vibration;

[0036] FIG. 3 is a chart of constant fluidity using table flow by quantity of plasticizer;

[0037] FIG. 4 is a chart of constant fluidity using penetration stress by quantity of plasticizer;

[0038] FIG. 5 is a controllable fluidity duration illustrating table flow by duration;

[0039] FIG. 6 is a controllable fluidity duration illustrating table flow by duration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0040] Florida and parts of Texas, Alabama, Missouri, Kentucky, Tennessee, Pennsylvania, and New Zealand have areas of sand and limestone which cause problems for soil compaction. Of great concern is the limestone pinnacles that form and need to be dispersed for proper foundation. Lack of proper compaction subjects an area to sinkhole formation, or sinkhole formation has occurred. In either event the soil needs to be stabilized to fill the sinkhole or the cavity addressed that can result in a sinkhole.

[0041] The fluidized sand of the instant invention is used as a filling material for cavities, sinkholes and the like open void ground spaces. In a preferred embodiment, each 1 m.sup.3 of fluidized sand receives a dosage comprising: Fluidizer consisting of a polyacrylamide and sodium polyacrylate anionic polymer of about 9.1 kg/m.sup.3 (=15.3 lb/yd.sup.3); Plasticizer consisting of polyethylene, polyamine, dimethylamine, and epichlorohydrin cationic polymer of about 0.7 kg/m.sup.3 (=1.2 lb/yd.sup.3); and a surface active agent of about 0.7 kg/m.sup.3 (=1.2 lb/yd.sup.3).

[0042] Nonionic surfactant surface agent may be selected from the group consisting of, for example, diethanolamide; Polyoxyethylene alkyl ether; or polyoxypropylene blockpolymer.

[0043] The fluidized sand can be injected after withdrawing piles in the natural ground by controlling the ingredients of the fluidized sand. After filling, the fluidized sand will return to the solid natural condition according to the effect of plasticizer previously added.

[0044] The fluidized sand is injected into a ground cavity wherein the material allows for compaction, permits water flow through the material, and can be easily excavated. The fluidized sand is produced by mixing graded sand, a anionic polymer fluidizer, a cationic polymer plasticizer, and a surface active agent. The fluidized sand unit weight can be changed by the amount of plasticizer included and the mixing/vibration duration.

[0045] Referring to FIG. 1, set forth is chart depicting one method of controlling unit weight wherein the unit weight can be changed through dosage of a plasticizer providing a controllable weight. The unit weight indicated in lb/ft.sup.3 is changed through the quantity of plasticizer added indicated in lb/yd.sup.3. The unit weight by this method is controlled trough dosage. For example, if 1.4 lb/yd.sup.3 of plasticizer is added the unit weight will be about 114 lb/ft.sup.3. If 1.9 lb/yd.sup.3 of plasticizer is added, the unit weight will be about 119 lb/ft.sup.3.

[0046] Polyacrylamide is defined as:

##STR00001##

[0047] and sodium polyacrylate defined as:

##STR00002##

[0048] Referring to FIG. 2, set forth is chart depicting another method of controlling unit weight, wherein the unit weight can be changed through mixing/vibration of the fluidized sand for a duration of time indicated in minutes. The unite weight in this example is controlled through mixing/vibration. For example, if an agitator is operated for 10 minutes the unit weight will be about 123 lb/ft.sup.3. If a shaking table is operated for about 20 minutes the unit weight will be 110 lb/ft.sup.3.

[0049] Polyethylene is defined as:

##STR00003##

[0050] Polyamine is defined as:

##STR00004##

[0051] Dimethylamine is defined as:

##STR00005##

[0052] and Epichlorohydrin is defined as:

##STR00006##

[0053] Referring to FIG. 3 a mortar flow table is provided illustrating a table flow (mm) and the quantity of plasticizer added indicated in lb/yd.sup.3 to obtain a constant fluidity. FIG. 4 compares penetration stress (Pa) to the quantity of plasticizer added indicated in lb/yd.sup.3.

[0054] Referring to FIG. 5, illustrated is the controllable fluidity duration by adding a fluidity keeper. 1.0 g of fluidity keeper allows a higher flow rate as compared to 0 g. FIG. 6 depict further illustrates the use of a lower flow rate with 1.0 g of fluidity keeper compared to 0 g of fluidity keeper.

[0055] Unique to this invention is the method of making sand into a composition having a suitable fluidity for filling cavities, having a small variation of property over time, having a constancy of volume and/or density during working. The fluidized composition comprising: adding a quantity of water to sand forming fluidized sand; admixing anionic polymers and cationic polymers to said fluidized sand forming a fluidized composition; measuring the density of the fluidized composition; injecting the fluidized composition into a cavity; sampling the injected fluidized composition by use of a Standard Penetration test; measuring the density of the sampled composition; wherein said injected fluidized composition having a constancy of volume and constancy of density compared to the fluidized composition before injection to provide soil stability and water migration.

[0056] The test work procedure comprising 1) Measuring the density of the fluid sand in the plant; 2) Injecting the fluid sand into the polyvinyl chloride pipe or the hole excavated by an auger using a squeeze pump; 3) Sampling the injected fluid sand by Standard Penetration Test; and 4) Measuring the density of the sampled sand of 3).

[0057] By way of example, results in the case of the polyvinyl chloride pipe: 1) Sand A(Komono-sand) γ=1.920 g/cm.sup.3 in the plant, 1.914 g/cm.sup.3 just after injection; γ=1.880 g/cm.sup.3 in the plant, 1.897 g/cm.sup.3 just after injection.

[0058] Results, in the case of 2) Sand B(Namekata-sand) γ=1.890 g/cm.sup.3 in the plant, 1.838 g/cm.sup.3 just after injection; γ=1.830 g/cm.sup.3 in the plant, 1.854 g/cm.sup.3 just after injection.

[0059] In the case of the polyvinyl chloride pipe: 1) Sand B(Namekata-sand) γ=1.890 g/cm.sup.3 in the plant, 1.879 g/cm.sup.3 just after injection.

[0060] The fluidized sand composition produced by mixing the graded sand, fluidizer and plasticizer, are used to fill ground cavities and natural sinkholes. Cavities such as those generated after extracting the piles in the natural ground by controlling the amount of plasticizer. Once the fluidized sand composition is placed into the cavity, the fluidized sand composition will return to the solid natural condition according to the effect of the plasticizer added previously. Testing has demonstrated that the density of the fluidized sand can be controlled to be consistent even if injection more than 10 m.

[0061] The term “about” means, in general, the stated value plus or minus 10%. The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more” or “at least one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternative are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.”

[0062] The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises,” “has,” “includes” or “contains” one or more steps or elements, possesses those one or more steps or elements, but is not limited to possessing only those one or more elements. Likewise, a step of a method or an element of a device that “comprises,” “has,” “includes” or “contains” one or more features, possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed.

[0063] One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.