JP5700679B2 - Method for investigating aging deterioration of chemical injection ground - Google Patents

Description

  The present invention relates to a method for investigating aged deterioration of a chemical solution injection ground.

Conventionally, in soft ground or the like, a chemical injection method has been used as an auxiliary method for stabilizing the ground during construction and a countermeasure method for preventing liquefaction due to earthquake motion. In the chemical injection method, by injecting an injection material such as a silica-based chemical into the ground, the soft ground is improved by reducing the hydraulic conductivity or increasing the strength.
Moreover, a standard penetration test etc. are known as a prior art for confirming the effect of the ground improvement by such a chemical | medical solution injection construction method. An example of the standard penetration test is described in Patent Document 1 and the like.

JP 2010-024717 A

  About the improvement ground using injection materials, such as a chemical | medical solution, a chemical | medical solution may be leached by groundwater and may deteriorate without maintaining intensity | strength. Therefore, when the improved ground is used for a long period rather than a short period, it is necessary to predict and grasp the degree of deterioration. However, the various tests that have been carried out in the past have not necessarily been suitable for investigating the aging of the ground due to chemical leaching.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to model chemical leaching by groundwater, and to investigate the aging degradation of the chemical injection ground that reflects this aging degradation. Is to provide a method.

1st invention for achieving the objective mentioned above is the process (a) which produces the test body imitating the chemical | medical solution injection | pouring ground which inject | poured the chemical | medical solution, and the acceleration magnification for accelerating | stimulating leaching of a chemical | medical solution for the said test body (B) a step of measuring the characteristic value of the specimen after the predetermined test period has elapsed after being installed in a fluid having a predetermined flow velocity determined by using the fluid; And the characteristic value of the specimen is a characteristic value of the chemical injection ground after the conversion elapsed period determined by the acceleration magnification and the test period, whereby the chemical injection after the conversion elapsed period has elapsed This is a method for investigating aging deterioration of a chemical-injected ground characterized by obtaining characteristic values of the ground.

It is desirable that the flow rate of the fluid is determined so as to satisfy a laminar flow condition.
The characteristic value preferably includes a chemical concentration.
The second invention is a step (a) in which a specimen is prepared by imitating a medicinal liquid injection ground into which a medicinal liquid has been injected, and a predetermined flow rate that is determined using an acceleration factor for accelerating the leaching of the chemical liquid. And (b) measuring the characteristic value of the specimen after a predetermined test period has elapsed, the fluid being installed in the fluid such that the fluid flows around the specimen. By determining the characteristic value of the specimen as the characteristic value of the chemical injection ground after the conversion elapsed period determined by the acceleration magnification and the test period, the characteristic value of the chemical injection ground after the conversion elapsed period is obtained, The flow rate of the fluid is defined as the product of the ratio of the mass of groundwater passing through the periphery of the solidified body assumed in the chemical injection ground and the mass of the solidified body, and the mass of the specimen, and the surface area of the specimen. The acceleration magnification is divided by the product of the fluid density and the product. Is aging research methods of liquid injection ground, characterized in that a value obtained by multiplying.

In the present invention, a specimen is prepared by imitating the ground into which the chemical solution has been injected, and the specimen is placed in a fluid having a predetermined flow velocity to promote deterioration. Then, after the predetermined test period has elapsed, the degree of deterioration of the specimen is measured, and the degree of deterioration of the actual chemical injection ground after the conversion elapsed period determined by the acceleration magnification and the test period has been obtained. Thereby, the secular change of the chemical | medical solution injection | pouring ground accompanying the leaching of the chemical | medical solution by groundwater is modeled, and the degree of degradation reflecting this can be predicted and grasped.
Further, by determining the flow velocity so as to satisfy the laminar flow condition, it is possible to perform a test that better simulates the state of groundwater in the ground, and to accurately grasp the degree of deterioration. Furthermore, by measuring the chemical concentration as the characteristic value, it is possible to predict the secular change of the chemical concentration that affects various characteristics of the ground. In addition, the flow rate of the fluid is determined by the product of the ratio of the mass of groundwater passing through the periphery of the solidified body assumed in the chemical injection ground and the mass of the solidified body and the mass of the test body, and the surface area of the test body. The value obtained by dividing the product by the product of the fluid density and the acceleration magnification is multiplied by the acceleration magnification, so that the fluid flow velocity is based on the flow velocity that causes a phenomenon similar to the actual chemical injection ground, and this is the acceleration magnification. Therefore, the degree of deterioration can be grasped more accurately.

  ADVANTAGE OF THE INVENTION According to this invention, the aging deterioration investigation method of the chemical | medical solution injection | pouring ground which can model the leaching of the chemical | medical solution by groundwater and can investigate the aging deterioration of the ground reflecting this is provided.

The figure which shows the outline of the experiment using the small specimen 3 The figure which shows the image of the groundwater which passes the circumference | surroundings of the solidified body 11 Diagram showing the relationship between uniaxial compressive strength, silica concentration and conversion elapsed time The figure which shows the outline | summary of the experiment using the large-sized specimen 27

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As an embodiment of the present invention, an example of an experiment using a small specimen 3 and an example of an experiment using a large specimen 27 will be described.

  First, a first embodiment of the present invention will be described with reference to FIGS. The first embodiment is an example in which an experiment using a small specimen 3 is performed.

  FIG. 1 is a diagram showing an outline of an experiment using a small specimen 3. FIG. 1A is a perspective view of a water tank 1 in which a specimen 3 is installed. FIG. 1B is a perspective view of the specimen 3.

  In the experiment using the specimen 3, first, a water tank 1 as shown in FIG. 1A is prepared. The water tank 1 is, for example, a flat non-metallic one having a size of 53 cm in length and 75 cm in width. A water injection pipe 5 is provided above the water tank 1, and a drain pipe 7 is provided at the lower part of the water tank 1. Water 9, which is a fluid, is injected into the water tank 1 as indicated by an arrow A from the water injection pipe 5. The water 9 flows through the water tank 1 at a predetermined flow velocity and is drained from the drain pipe 7 as indicated by an arrow B. The flow rate of the water 9 in the water tank 1 is controlled by controlling the water injection / drainage amount. The flow velocity is determined using laminar flow conditions and the acceleration magnification. A method for determining the flow rate will be described later. The water 9 is set at an appropriate temperature. For example, the water temperature is 20 ° C.

  Further, a specimen 3 as shown in FIG. The specimen 3 is prepared by injecting a silica-based chemical solution, imitating the ground into which the chemical solution has been injected. The specimen 3 is manufactured using, for example, a cylindrical small mold having a radius r = 2.5 cm and a height h = 10 cm. The relative density (gap ratio) of the specimen 3 is determined according to the gap ratio of the target ground, for example. Note that when the specimen 3 is manufactured, a sample collected from the actual ground into which the chemical solution has been injected may be used. The characteristic values such as the chemical concentration and the uniaxial compressive strength of the specimen 3 before the test are previously measured and grasped.

Below, the method of calculating | requiring the flow velocity of the water 9 is demonstrated. FIG. 2 is a diagram showing an image of groundwater passing through the periphery of the solidified body 11 with a chemical solution, assumed in an actual chemical solution injection ground. The solidified body 11 is spherical. Assuming that the volume of the consolidated body 11 is V, the surface area is S, the mass is M, and the assumed flow velocity of groundwater is v, the flow rate of groundwater passing around the consolidated body 11 as shown by the arrow D in FIG. Q = S × v. Assuming that the ratio between the mass converted value Q × ρ _{w of the} passing flow rate (the mass of groundwater passing around the consolidated body 11) and the mass M of the consolidated body 11 is a dimensionless value R, R = Q × ρ _w / M. ρ _w is the density of water.

The volume of the specimen 3 shown in FIG. 1B is V ′, the surface area is S ′, and the mass is M ′. The ratio of passes around the specimen 3 '× [rho _w specimen mass M' mass conversion value Q of the passing flow rate of water 9, applying the similarity law to the same as the dimensionless value R, Q '= R × M 'next / [rho _w, flow velocity v required to cause a similar to the actual ground behavior experiments using specimens 3' = Q '/ S' = R × M '/ (S' × ρ _w ).

In the experiment using the specimen 3, in order to promote the leaching of the chemical solution, the deterioration promotion experiment is performed by setting the flow rate of the water 9 to n times the flow rate v ′ necessary to cause a phenomenon similar to that in the field. n is an acceleration magnification for promoting leaching of the chemical solution.
That is, the flow rate of the water 9 is the product of the ratio R of the mass of ground water passing through the periphery of the consolidated body 11 to the mass of the consolidated body 11 and the mass M ′ of the test body 3, and the surface area S of the test body 3. It is determined to be a value obtained by multiplying the value v 'divided by the product of' and the density ρ _{w of} water 9 by the acceleration magnification n.

  In the deterioration promotion experiment, the prepared specimen 3 is immersed in the water tank 1 in which the water 9 having a flow velocity v ′ × n flows, so that the entire specimen 3 is immersed in the water 9. The leaching of the chemical solution 3 is promoted. Then, after a predetermined test period has elapsed, the characteristic value of the specimen 3 is measured. The characteristic values are uniaxial compressive strength, chemical concentration, and the like. By using the measured characteristic value of the specimen 3 as the characteristic value of the actual medicinal solution injection ground after the conversion elapsed period determined by n × (test period) according to the acceleration magnification n and the test period, the conversion elapsed period elapsed The characteristic value of the actual chemical solution injection ground is obtained later.

  FIG. 3 is a diagram showing the relationship between the uniaxial compressive strength, the chemical concentration (silica concentration), and the conversion elapsed period (converted elapsed days) obtained as the characteristic values of the specimen 3. The relationship between the conversion elapsed period and the characteristic value of the specimen 3 obtained by an experiment conducted at a predetermined acceleration magnification using the specimen 3 is arranged in a graph as shown in FIG. 3, for example.

  FIG. 3A is a diagram schematically showing the relationship between the uniaxial compressive strength of the specimen 3 and the conversion elapsed period. Data 13 shows a value obtained from the deterioration promotion test result of the specimen 3 having a relative density of 80%, data 15 having a relative density of 60%, and data 17 having a relative density of 40%. Each uniaxial compressive strength is a value obtained by estimating the uniaxial compressive strength of the actual chemical solution injection ground when the conversion elapsed period has elapsed.

  FIG. 3B is a diagram schematically showing the relationship between the silica concentration of the specimen 3 and the conversion elapsed period. Data 19 is a relative density of 80%, data 21 is a relative density of 60%, and data 23 is a value obtained from a result of the accelerated acceleration test of the specimen 3 having a relative density of 40%. Each silica density | concentration becomes the value which estimated the silica density | concentration of the actual chemical | medical solution injection | pouring ground at the time of conversion elapsed time passing.

  FIG. 3 shows that the silica concentration and the uniaxial compressive strength tend to decrease as the conversion elapsed period increases. Thus, the relationship between the decrease in silica concentration and the decrease in uniaxial compressive strength is suggested. The above-described experimental method models the state in which the strength of the ground changes due to leaching of the chemical solution, and is considered to be effective for grasping the secular change of the chemical injection ground.

  As described above, according to the present embodiment, a specimen is prepared by imitating the ground into which the chemical solution has been injected, and the specimen is placed in running water at a flow rate determined using the acceleration magnification to promote deterioration. Then, after the predetermined test period has elapsed, the degree of deterioration of the specimen is measured, and the degree of deterioration of the actual chemical injection ground after the conversion elapsed period determined by the acceleration magnification and the test period has been obtained. Thereby, the grade of the secular change of the chemical | medical solution injection | pouring ground accompanying the leaching of the chemical | medical solution by groundwater can be estimated and grasped | ascertained. In addition, by setting the flow velocity so as to satisfy the laminar flow condition, it becomes a good simulation of the state of groundwater in the ground, so the degree of deterioration can be accurately grasped, and by measuring the chemical concentration as a characteristic value, Predict changes over time in chemical concentrations that affect various characteristics of the ground. Furthermore, the flow rate of the fluid is determined by the product of the ratio of the mass of groundwater passing through the periphery of the solidified body assumed in the chemical injection ground and the mass of the solidified body and the mass of the test body, and the surface area of the test body. By dividing the product by the product of the fluid density and multiplying by the acceleration factor, the fluid flow rate is based on the flow rate that causes a phenomenon similar to the actual chemical injection ground, and multiplied by the acceleration factor. Therefore, the degree of deterioration can be grasped more accurately.

  In the present embodiment, the uniaxial compressive strength, the chemical concentration, and the like are measured as the characteristic values of the specimen, but the characteristic values are not limited to these. For example, the water permeability coefficient or the volume of the specimen may be used. Moreover, you may measure the leaching rate which the chemical | medical solution leached in water by measuring the chemical | medical solution density | concentration of a test piece and the chemical | medical solution density | concentration in water, such as a waste_water | drain. Further, if necessary, the state of the specimen may be recorded with a photograph or sketch immediately after the water immersion or after a predetermined test period, and the leaching range of the chemical solution may be observed.

  Furthermore, in the present embodiment, the specimen is installed by forming a laminar flow with a predetermined flow velocity in a box-shaped water tank whose upper surface is open. However, the present invention is not limited to this, and for example, a predetermined flow velocity is provided inside the tubular body. The laminar flow may be formed and the specimen may be installed. Further, the shape and size of the specimen are not limited to those described above.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is an example in which an experiment using a large specimen 27 is performed.
FIG. 4 is a diagram showing an outline of an experiment using the large specimen 27. FIG. 4 is a perspective view of the water tank 25 in which the specimen 27 is installed.

  In an experiment using the specimen 27, first, a water tank 25 as shown in FIG. 4 is prepared. The water tank 25 is, for example, a non-metallic plane having a size of 115 cm in length and 135 cm in width. Further, a water injection pipe 29 and a drain pipe 31 similar to the water injection pipe 5 and the drain pipe 7 are provided. As in the first embodiment, the water 33 is adjusted to flow in the water tank 25 under a laminar flow condition and at a predetermined flow rate determined using the acceleration magnification n.

  Further, a specimen 27 as shown in FIG. 4 is produced. Like the specimen 3, the specimen 27 is produced by imitating the ground into which the chemical solution has been injected. In the present embodiment, the specimen 27 is a spherical chemical solution consolidated soil and has a radius of, for example, about 20 cm.

Regarding the flow rate of the water 33, the volume of the specimen 27 shown in FIG. 4 is V ″, the surface area is S ″, the mass is M ″, and the water 33 passing around the specimen 27 is the same as described above. the ratio of 'the × [rho _w specimen mass M' passing flow of mass conversion value Q '' of, applying the similarity law to the same as the ratio R described above, Q '' = R × M '' / ρ w Thus, the flow velocity v ″ = Q ″ / S ″ = R × M ″ / (S ″ × necessary for causing a phenomenon similar to the actual chemical injection ground in the model experiment using the specimen 27 ρ _w ).

  Even in the experiment using the specimen 27, in order to promote the leaching of the chemical solution, the deterioration promotion experiment is performed by setting the flow rate of the water 33 to n times the flow rate v ″ necessary to cause a phenomenon similar to that in the field.

  The experiment using the specimen 27 is also performed in the same procedure as in the first embodiment. That is, the specimen 27 is immersed in the water tank 25 in which the water 33 having the flow velocity v ″ × n flows, so that the whole specimen 27 is submerged in the water 33 to promote the leaching of the chemical solution. Then, after a predetermined test period has elapsed, the characteristic value of the specimen 27 is measured. By using the measured characteristic value of the specimen 27 as the characteristic value of the actual chemical injection ground after the conversion elapsed period determined by n × (test period) according to the acceleration magnification n and the test period, the conversion elapsed period elapsed The characteristic value of the actual chemical injection ground later is obtained. Thereby, the same effect as that of the first embodiment can be obtained.

  Note that an appropriate acceleration magnification may be selected by the above-described experiment using the small specimen 3, and the above experiment using the large specimen 27 may be performed at the selected acceleration magnification. In this case, in the plurality of water tanks 1, the same experiment as described above is performed at different flow rates corresponding to different acceleration magnifications, the experimental results are examined, and an appropriate acceleration magnification n is set to promote the deterioration of the specimen. Select. Thereafter, an experiment similar to the above is performed using the large specimen 27 at a flow rate corresponding to the selected acceleration magnification n. According to the knowledge of the inventors, the acceleration magnification n is preferably about n = 10. In this case, it is possible to predict the deterioration over time of the actual chemical injection ground more accurately.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs.

1, 25 ......... Water tank 3, 27 ......... Specimen 5, 29 ......... Water injection pipe 7, 31 ...... Drain pipe 9, 33 ......... Water 11 ......... Consolidated body

Claims (4)

A step (a) of producing a specimen imitating the chemical injection ground into which the chemical was injected;
The specimen was placed in a fluid at a predetermined flow rate determined using an acceleration magnification for promoting leaching of the chemical solution so that the fluid flows around the specimen, and a predetermined test period had elapsed. And (b) measuring the characteristic value of the specimen afterwards,
The characteristic value of the specimen is a characteristic value of the chemical solution injection ground after the conversion elapsed period determined by the acceleration magnification and the test period, so that the chemical injection ground after the conversion elapsed period has elapsed. A method for investigating aging deterioration of chemical injection ground characterized by obtaining characteristic values.   The method for investigating aged deterioration of a chemical injection ground according to claim 1, wherein the flow velocity of the fluid is determined so as to satisfy a laminar flow condition.   The method for investigating aged deterioration of a chemical solution injection ground according to claim 1 or 2, wherein the characteristic value includes a chemical solution concentration. A step (a) of producing a specimen imitating the chemical injection ground into which the chemical was injected;
A step of installing the specimen in a fluid having a predetermined flow rate determined using an acceleration magnification for promoting leaching of a chemical solution, and measuring a characteristic value of the specimen after a predetermined test period has elapsed ( b) and
The characteristic value of the specimen is a characteristic value of the chemical solution injection ground after the conversion elapsed period determined by the acceleration magnification and the test period, so that the chemical injection ground after the conversion elapsed period has elapsed. Find the characteristic value
The flow rate of the fluid is the product of the ratio of the mass of groundwater passing through the periphery of the solidified body assumed in the chemical injection ground and the mass of the solidified body, and the mass of the specimen, and the surface area of the specimen. wherein the value obtained by dividing the product of the density of the fluid, aging searching method for drug injection ground, characterized in that a value obtained by multiplying the accelerator magnification.

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