JP6907611B2 - Quality control method for stabilizers - Google Patents

Description

The present invention relates to a quality control method for a stabilizer used when drilling a hole in the ground to construct an underground hole and constructing an underground concrete structure in the underground hole.

Conventionally, when excavating concrete structures such as cast-in-place concrete piles and continuous underground walls in the ground, not only the wall collapse of the excavation hole is prevented, but also the transportation of excavated earth and sand and the underground hole are carried out. A stabilizer is used as a replacement fluid when placing underwater concrete.

In the state of being supplied into the underground hole, the stabilizer tends to change in its properties due to the mixing of excavated earth and sand or contact with the cement component at the time of placing concrete, and is likely to cause deterioration. Therefore, when it is recovered from the underground hole, quality control is performed in order to grasp its properties.

For example, in Patent Document 1, the deterioration factors of the stabilizing liquid can be grasped by measuring the numerical values of each of the four control items (specific gravity, funnel viscosity, filtered water amount, pH) for the stabilizing liquid at the time of construction. , A method of selecting a regeneration method according to the deteriorated state from the regeneration chart of the stabilizer is disclosed.

Japanese Unexamined Patent Publication No. 11-286930

If the construction target area for excavation work is an area adjacent to the sea, or if it is not natural ground such as the construction site of an existing structure or backfill soil, the ground may contain various chemical components. many. Then, these chemical components cause agglomeration of the stabilizer and cause deterioration.

Under these circumstances, among the four control items disclosed in Patent Document 1, the amount of filtered water is suitable as a control item for grasping deterioration due to aggregation of the stabilizer. However, the filtration test for measuring the amount of filtered water not only takes a long time, but also requires a lot of labor and is inferior in economy.

The present invention has been made in view of such a problem, and a main object thereof is a stabilizing liquid capable of grasping a deteriorated state due to agglomeration of a stabilizing liquid by a simple method in a short time and surely. Is to provide a quality control method for.

In order to achieve such an object, the quality control method for a stabilizing liquid of the present invention constructs the underground concrete structure when constructing a cast-in-place concrete underground concrete structure in an underground hole using the stabilizing liquid. While measuring the apparent viscosity of the stable liquid, the actual measured value of the apparent viscosity is obtained in a timely manner, and the deterioration state due to the aggregation of the stable liquid is managed based on the measured apparent viscosity value and the apparent viscosity control value. This is a method for controlling the quality of the stabilizer, and the apparent viscosity control value is the amount of filtered water set based on the relationship between the amount of filtered water and the apparent viscosity when the Ca component is mixed in the stabilizer before construction. The result of measuring the amount of filtered water together with the apparent viscosity using a stabilizer that has the apparent viscosity corresponding to the quality control standard value and fills the underground pores during construction, and the amount of filtered water before construction. It is characterized in that the apparent viscosity control value is modified based on the relationship between the apparent viscosity and the apparent viscosity.

Further, the quality control method for the stabilizer of the present invention is characterized in that the apparent viscosity is measured by a B-type viscosity measurement test.

According to the quality control method of the stabilizer of the present invention, the deteriorated state due to the aggregation of the stabilizer is controlled by using the measured viscosity value, so that the measurement is performed in comparison with the case of controlling by using the amount of filtered water. It is possible to significantly reduce the labor and cost involved in the test. This makes it possible to quickly and economically grasp the deterioration state due to the aggregation of the stabilizing liquid.

In addition, because the test method for measuring the apparent viscosity is simple and economical, when the measured value of the apparent viscosity increases with time, the interval between measurement periods is narrowed to obtain the apparent viscosity. It is also possible to increase the frequency of monitoring the measured values.

By doing so, changes in the deterioration state due to the aggregation of the stabilizer can be grasped at an early stage, so appropriate regeneration treatment is performed to improve the properties of the stabilizer, and deterioration that exceeds the apparent viscosity control value is prevented. It is possible to prevent it in advance. As a result, the amount of stabilizing liquid to be disposed of can be significantly reduced, the life of the stabilizing liquid can be extended, and the underground concrete structure can be constructed using the stabilizing liquid safely and economically. It will be possible.

According to the present invention, since the deterioration state due to the aggregation of the stable liquid can be grasped by measuring the apparent viscosity, it is shorter than the case where the amount of filtered water is measured and grasped by a simple test method. It is possible to control the quality of the stable liquid in a timely and economical manner.

It is a figure which shows the underground concrete structure in embodiment of this invention. It is a figure which shows the state of constructing the underground hole using the stabilizing liquid in embodiment of this invention. It is a figure which shows the regeneration processing equipment of the stabilizer in embodiment of this invention. It is a figure which shows the ground excavator in embodiment of this invention. It is a figure which shows the relationship between the filtered water amount of the stabilizer and the apparent viscosity (B type viscosity) in embodiment of this invention. It is a figure which shows the deterioration state caused by the aggregation of the stabilizer by the apparent viscosity at the initial stage of construction in embodiment of this invention. It is a figure which shows the deterioration state due to the aggregation of the stabilizer by the apparent viscosity in the middle stage of construction in embodiment of this invention. It is a figure which shows the state of measuring the apparent viscosity (B type viscosity) by the B type viscometer in embodiment of this invention.

The quality control method of the stabilizer in the present embodiment is to determine the deterioration state due to the aggregation of the stabilizer that protects the hole wall during the construction period in which the underground hole is provided in the ground to construct the underground concrete structure. This is a method of controlling by adopting the apparent viscosity instead of the amount of filtered water, which is one of the quality control items of the stabilizer. The quality control method of the stabilizer will be described below with reference to FIGS. 1 to 8.

As shown in the plan view of FIG. 1, the underground concrete structure 8 in the present embodiment is a pile foundation structure composed of a plurality of cast-in-place concrete piles 81, and the cast-in-place concrete pile 81 excavates the ground. After constructing the underground hole 1, it is constructed by placing underwater concrete in the underground hole 1.

Then, as shown in FIG. 2, the underground hole 1 before the underwater concrete is poured is filled with the stabilizing liquid 3 in order to prevent the hole wall 2 from collapsing. The stabilizer 3 may be either a bentonite-based stabilizer having a main material of bentonite or a polymer-based stabilizer having a main material as a polymer.

When the stabilizing liquid 3 is supplied to the underground hole 1, it permeates into the ground from the hole wall 2, and bentonite contained in the stabilizing liquid 3 adheres between the soil particles to form a mud cake in the hole wall 2. To form. By having the ability to form a mud cake on the hole wall 2, that is, the so-called wall-building performance, the hydraulic pressure of the stabilizing liquid 3 can be applied to the hole wall 2 through the mud cake. As a result, the stabilizing liquid 3 resists the earth pressure and water pressure on the ground side to prevent the hole wall 2 from collapsing, and secures the stability of the hole wall 2.

On the other hand, the stabilizer 3 also functions as a discharge medium for excavated earth and sand, and is lifted together with excavated earth and sand generated by excavation of the ground by the underground excavator 4. The stable liquid 3 that has been pumped up has changed its properties due to the mixing of excavated earth and sand, and is in a state where deterioration is likely to proceed. Therefore, as shown in FIG. , Physical processing to restore function and regeneration processing such as regeneration formulation are carried out.

The regeneration processing equipment 5 is generally stored in a sediment separation device 51 that separates excavated sediment from a stabilizer 3 mixed with excavated sediment, a storage tank 52 that stores the stabilizer 3 in which excavated sediment is separated, and a storage tank 52. A blending device 53 for regenerating and blending the stabilized liquid 3 is provided.

The earth and sand separation device 51 is equipped with, for example, a settling tank for sedimenting excavated earth and sand by gravity, a vibrating mud screen for mechanically separating excavated earth and sand, a cyclone, a screw decanter, and the like. Further, the blending device 53 is provided with a device for adding a material to be replenished to the stabilizer 3 and mixing and stirring the mixture.

Therefore, the stabilizer 3 supplied to the underground hole 1 is lifted from the underground hole 1, and then the mixed excavated earth and sand are separated by the earth and sand separation device 51, and the chemical treatment using a dispersant or the like is used. A regenerative treatment such as a specific treatment and a regenerative preparation is carried out. In this way, the stabilizing liquid 3 whose functions such as the stability of the hole wall 2 and the discharge medium of the excavated soil have been restored is supplied to the underground hole 1 again for circulation use.

However, in the stabilizer 3, fine particles that cannot be removed even by the earth and sand separation device 51 used during the physical treatment remain. Further, when constructing the underground concrete structure 8, chemical deterioration is likely to proceed in the following steps.

First, as shown in FIG. 2, the stabilizer 3 is applied to the ground where the fluidized soil 6 is filled or the groundwater 7 is mixed with seawater as protection near the mouth of the underground hole 1. When excavating the ground while supplying and constructing an underground hole 1, not only fluidized soil, excavated soil, groundwater, etc. are mixed in the stabilizing liquid 3, but also the Ca component and Na component eluted from these are stable. It is mixed with the liquid 3.

As a result, the stabilizing liquid 3 becomes a gelled state, and the agglomerates adhere to the hole wall 2 of the underground hole 1 or settle on the bottom of the hole. For this reason, placing underwater concrete in the underground hole 1 after construction tends to cause poor placement.

Further, when the underwater concrete is placed in the underground hole 1 after construction, the stabilizer 3 comes into contact with the surface of the underwater concrete. Therefore, in the vicinity of this contact surface, the Ca component of the concrete and the bentonite contained in the stabilizer 3 A chemical reaction with negative ions occurs. Then, frogs are likely to be generated in the stabilizer 3, and these frogs adhere to the reinforcing bar cages constituting the cast-in-place concrete piles installed in the underground hole 1. As a result, poor adhesion may occur between the underwater concrete and the reinforcing bar cage.

As described above, the stabilizer 3 in a state of gelling or frog formation is in a state of deteriorated in properties and quality. Therefore, even if the deteriorated stabilizer 3 is circulated and used as it is, the original function of preventing the hole wall 2 from collapsing and the function as a replacement fluid for placing underwater concrete cannot be sufficiently satisfied. Occurs. Therefore, the stabilizer 3 during the construction period is subjected to a quality control test in a timely manner based on preset control items and quality control standards.

As control items, the amount of filtered water, viscosity, specific gravity, sand content and pH are generally known. Among them, the amount of filtered water is an item for evaluating the wall-building performance that contributes to the prevention of collapse of the hole wall 2 described above, and when the amount of filtered water shows an increasing tendency with time, it is caused by aggregation or the like. It is presumed that the wall-building performance is deteriorating due to the deterioration of the stabilizer 3.

However, it is known that the work of managing the deteriorated state due to aggregation using the amount of filtered water is not only expensive for the filtration tester, but also complicated and takes time for the test. For this reason, it is often difficult to take measures such as promptly conducting tests or conducting tests at high frequency so that fluctuations in the deterioration state can be grasped at an early stage.

Under these circumstances, as a result of diligent studies, the inventors have found that the apparent viscosity, which can be measured quickly by a simple test compared to the amount of filtered water, correlates with the amount of filtered water of the stabilizer 3. It was found that it has. Here, the apparent viscosity is an index completely different from the funnel viscosity measured as the viscosity in the standard control item of the quality control of the stabilizer 3.

That is, the apparent viscosity is an index used for grasping the flow characteristics of a liquid whose shear stress is not proportional to the shear rate, that is, a so-called non-Newtonian fluid, and is a value obtained by dividing the shear stress by the corresponding shear rate. The shear stress means the internal frictional force per unit area of the plane parallel to the flow of the liquid, and the shear speed means the velocity gradient in the direction perpendicular to the flow of the fluid.

In order to verify the correlation between the amount of filtered water and the apparent viscosity of the stabilizer 3, a laboratory experiment was carried out according to the following procedure.

First, a ground survey is conducted on the ground where the underground hole 1 for supplying the stabilizer 3 is constructed, and a columnar map and a particle size distribution map are created to form the grains of soil particles constituting the ground. Understand the relationship between diameter and mass. After that, the earth and sand that are close to the ground are selected based on the particle size distribution map, and a soil sample of the ground is prepared.

Next, when constructing the underground hole 1 while supplying the stabilizer 3, the predicted amount of excavated soil that is expected to be mixed in the stabilizer 3 was calculated, and the liquid was prepared based on the construction plan. A soil sample is mixed into the stabilizer 3 in an amount corresponding to the predicted mixing amount.

Here, the predicted mixed amount of excavated soil represents the ratio of the difference between the excavated soil amount and the sediment storage amount of the underground excavator 4 to the excavated soil amount generated by excavation by the underground excavator 4. Estimated from the sediment mixing rate.

For example, in the present embodiment, the underground excavator 4 employs a so-called excavation bucket composed of a conical portion 41 having an excavation blade and a cylindrical portion 42 having a side cutter 43 as shown in FIG. .. When the ground is excavated by the underground excavator 4, the hole diameter R1 of the underground hole 1 becomes the sum of the diameter of the columnar portion 42 and the protrusion amount of the side cutter 43.

Therefore, the amount of excavated soil when excavating the ground with the underground excavator 4 is the sum of the outer volume of the cylinder having the diameter R1 and the outer volume of the conical portion 41 described above. On the other hand, since the underground excavator 4 has a sediment storage portion inside the columnar portion 42 and the conical portion 41, the sediment storage capacity is the sum of the internal volume of the columnar portion 42 and the internal volume of the conical portion 41. It will be the combined amount. By using these quantities, the predicted sediment mixing rate may be calculated and the predicted sediment mixing amount may be estimated from the estimated excavated soil volume.

After that, assuming the case where the fluidized soil 6 is present in the ground or the case where the stabilizer 3 comes into contact with the underwater concrete, the stabilizer mixture is mixed with the soil sample in an amount corresponding to the predicted mixing amount as described above. The Ca component is added to 3. In the present embodiment, only 10 samples of the stabilizer 3 mixed with the soil sample are prepared, and 10 kinds of cement addition rates are increased by 0.1% from 0.1% to 1.0%. Cement-based solidifying material is added to each.

Next, the amount of filtered water and the apparent viscosity of each of the stabilizers 3 to which 10 kinds of cement-based solidifying materials are added are measured. The amount of filtered water may be measured by a conventional filtration test using a filtration tester.

On the other hand, the apparent viscosity is measured by a B-type viscosity measurement test using a B-type viscometer (single cylindrical rotational viscometer: Brookfield-type viscometer) 11 as shown in FIG. 8 (a). .. The B-type viscosity measurement test is a test for measuring the viscosity resistance torque of the liquid sample 100 acting on the rotor 112 when the rotor 112 such as the cylinder or disk of the B-type viscometer 11 is rotated in the liquid sample 100. The viscosity (B-type viscosity) is converted into a viscosity value based on this torque value and a predetermined coefficient.

The measurement of the apparent viscosity is not limited to the B-type viscosity measurement test. For example, a measurement test capable of measuring the apparent viscosity of the stabilizer 3, such as a measurement test using a cone-plate type rotational viscometer (cone plate type viscometer) or a co-axis double cylindrical rotational viscometer (Quet type viscometer). Any method may be adopted as long as it is a method.

FIG. 5 shows an example of a graph in which the amount of filtered water and the apparent viscosity (B-type viscosity) measured from each of the 10 types of stabilizers 3 in which the cement addition rate is changed are plotted. Looking at this, as the cement addition rate to the stabilizer 3 increases, that is, as the amount of Ca component mixed in increases, both the filtered water amount and the apparent viscosity (B-type viscosity) of the stabilizer 3 increase. It can be seen that there is a high correlation between the two.

Therefore, in the present embodiment, the apparent viscosity (B-type viscosity) of the stabilizer 3 is used to control the deterioration state due to aggregation, and the apparent viscosity (B-type viscosity) tends to increase with time. In this case, it was decided that the stabilizer 3 was presumed to be deteriorated due to aggregation.

Then, in the general quality control method of the stabilizer 3, the control standard value of the filtered water amount is set to 30 ml, and when the measured value of the filtered water amount exceeds these control standard values, the stabilizer 3 improves the wall-building performance. It is determined that it has been lost. Therefore, the apparent viscosity (B-type viscosity) corresponding to the amount of filtered water of 30 ml was set to the apparent viscosity control value, and the stabilizer 3 was controlled.

Hereinafter, a quality control method for the stabilizing liquid 3 will be described in which the deterioration state caused by the aggregation of the stabilizing liquid 3 is controlled using the apparent viscosity (B-type viscosity) described above.

In the present embodiment, as shown in FIG. 1, when constructing a plurality of cast-in-place concrete piles 81 in the construction target area of the underground concrete structure 8, among the plurality of cast-in-place concrete piles 81, the initial construction An example is the case where about 15% of the total is constructed in the stage and about 40 to 60% of the total is constructed in the middle stage of construction.

<Pretreatment process>
By the method described above, a ground survey is conducted on the ground where the underground concrete structure 8 is planned to be constructed, a soil sample is prepared, and the predicted sediment mixing rate of the excavated sediment is calculated. Then, the soil sample is mixed with the stabilizer 3 prepared based on the construction plan in an amount corresponding to the predicted mixing amount, a cement-based solidifying material is added, and the amount of filtered water and the apparent viscosity (B-type viscosity) are measured. , The apparent viscosity control value corresponding to the filtered water volume of 30 ml is set from the relationship between the two.

In the present embodiment, when the soil sample is mixed into the stabilizing liquid 3, not only the amount corresponding to the predicted sediment mixing rate calculated above but also the stabilizing liquid is circulated and used at the time corresponding to the middle stage of construction. The amount of fine particles that is expected to accumulate in 3 is mixed. This prevents the quality control related to the deterioration state due to the aggregation of the stabilizer 3 from becoming excessive control.

Looking at FIG. 5, since the apparent viscosity (B-type viscosity) when the amount of filtered water is 30 ml is 45 mpas, this value is set to the apparent viscosity control value. Then, the stabilizer 3 is managed so that the measured apparent viscosity value of the stabilizer 3 acquired in a timely manner does not exceed 45 mpas. When measuring the apparent viscosity (B-type viscosity), the rotor 112 of the B-type viscometer 11 is set to 60 rpm.

<Construction process of underground concrete structure>
The underground concrete structure 8 is constructed through the following steps. That is, after the underground hole 1 is constructed, the bottom is drained and the primary slime treatment is performed, the reinforcing bar cage is built, the tremie pipe is built, the underwater concrete is cast through the tremie pipe and cured, and the cast-in-place concrete pile. The process of constructing 81 is repeated for the number of cast-in-place concrete piles 81 to be constructed.

Then, the quality control of the stabilizer 3 is carried out in a timely manner with respect to the stabilizer 3 after the primary slime treatment in the above steps. The stabilizing liquid 3 supplied to the underground hole 1 is lifted to the ground through a stabilizing liquid discharge port of a slime processing machine (not shown) in the primary slime processing step, and is supplied to the recycling processing equipment 5. .. Therefore, a sample is taken from the stabilizer 3 that has been lifted to the ground through the stabilizer discharge port, and the deterioration state due to the aggregation of the stabilizer 3 is grasped using this sample.

<Initial stage of construction>
In the initial stage of construction, that is, until about 15% of the total number of cast-in-place concrete piles 81 is constructed, the B-type viscosity measurement test is performed multiple times to obtain the apparent viscosity measurement value, and deterioration due to aggregation is obtained. It not only manages the state, but also captures changes over time.

Specifically, if the measured apparent viscosity value does not exceed the apparent viscosity control value set in the pretreatment step and no change with time is observed, the stabilizer 3 is in a healthy state. Judging that, it is recycled as it is without carrying out regenerative preparation.

Further, if the measured apparent viscosity value does not exceed the apparent viscosity control value but tends to increase with time, it can be estimated that deterioration due to aggregation is progressing in the stabilizer 3. Therefore, before the apparent viscosity control value is exceeded, the stabilizer 3 stored in the storage tank 52 is supplied to the compounding apparatus 53, and regenerative compounding such as adding an additive such as a dispersant or sodium carbonate is performed. , The stabilizing liquid 3 is regenerated.

On the other hand, when the measured apparent viscosity value exceeds the controlled apparent viscosity control value, it can be estimated that the wall-building performance is lost in the stabilizer 3 due to the progress of deterioration due to aggregation. Therefore, although the stabilizing liquid 3 is regenerated as described above, if the functional recovery cannot be expected even after the regenerating treatment, the stabilizing liquid 3 is disposed of without being recycled.

Looking at the graph of FIG. 6 showing the results of measuring the apparent viscosity measured twice at the initial stage of construction, the apparent viscosity measured values did not exceed the apparent viscosity control values at 15 mps and 35 mps. As a result, it can be seen that the stabilizer 3 has not lost its wall-building performance, but has been deteriorated due to aggregation. Therefore, it is advisable to regenerate the stabilizer 3 and improve the properties of the stabilizer 3 by the above method.

<Mid-term construction stage>
In the middle stage of construction, that is, until about 40 to 60% of the total of the plurality of cast-in-place concrete piles 81 is constructed, the apparent viscosity measured value by the B-type viscosity measurement test is acquired as in the initial stage of construction. In addition to managing the deterioration state caused by agglomeration and grasping changes over time, the amount of filtered water is also measured by a filtration test.

This is because the apparent viscosity control value set in the pretreatment stage is filtered in order to ensure the reliability of the quality control method that controls the deterioration state caused by the aggregation of the stabilizer 3 using the apparent viscosity (B-type viscosity). This is to confirm that it corresponds to the water volume control regulation value.

Looking at the graph of FIG. 7 showing the results of measuring the apparent viscosity measured value and the filtered water amount 5 times in the middle stage of construction, the filtered water amount is about 35 ml at least when the apparent viscosity measured value is 40 mps, and the pretreatment It is highly possible that the apparent viscosity control value of 45 mpas set in the step does not correspond to the control standard value of 30 ml of the amount of filtered water.

Therefore, in consideration of safety, the apparent viscosity control value was reviewed, and the apparent viscosity control value was set to 40 mpas in the subsequent middle stage of construction. In all the results of the B-type viscosity measurement test and the filtration test performed multiple times, when the measured apparent viscosity value is 45 mps or less and the amount of filtered water is less than 30 ml, it is not necessary to correct the apparent viscosity control value. be.

<Late stage of construction>
In the latter stage of construction, as in the initial stage of construction, until the construction of all cast-in-place concrete piles 81 is completed, the B-type viscosity measurement test is performed multiple times to obtain the apparent viscosity actual measurement value, and the deterioration state due to aggregation is obtained. Manage and understand changes over time. For the apparent viscosity control value, the value revised in the middle stage of construction will be adopted.

As described above, by using the apparent viscosity (B-type viscosity) in the quality control method of the stabilizer 3, the agglomeration of the stabilizer 3 is quickly and economically carried out in a simple test as compared with the case where the amount of filtered water is used. It is possible to grasp the deterioration state caused by.

In addition, because the test method for measuring the apparent viscosity (B-type viscosity) is simple and economical, if the measured apparent viscosity value increases over time, the interval between measurement periods may be narrowed. It is also possible to increase the frequency of monitoring the measured apparent viscosity. By doing so, it is possible to grasp the fluctuation of the deterioration state due to the aggregation of the stabilizer 3 at an early stage. Therefore, appropriate regeneration treatment is performed to improve the properties of the stabilizer 3, and the apparent viscosity control value is exceeded. It is possible to prevent deterioration before it happens.

As a result, the stabilizer 3 to be disposed of can be significantly reduced, the life of the stabilizer 3 can be extended, and the underground concrete structure 8 can be constructed by using the stabilizer 3 safely and economically. Can be carried out.

The quality control method for the stabilizer 3 of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.

For example, in the present embodiment, the apparent viscosity measured value was acquired twice in the initial stage of construction, and the apparent viscosity measured value and the amount of filtered water were measured five times in the middle stage of construction. However, the number of measurements is not necessarily limited to this. In particular, in the middle stage of construction, these measurements may be carried out every month, or one by one for each cast-in-place concrete pile 81 to be constructed.

Further, in the present embodiment, a pile foundation structure having a plurality of cast-in-place concrete piles 81 is adopted as the underground concrete structure 8, but the present invention is not necessarily limited to this. For example, any underground concrete structure 8 may be used as long as it is a cast-in-place concrete structure constructed in the ground, such as an underground continuous wall.

Further, in the B-type viscosity test for measuring the apparent viscosity (B-type viscosity), as shown in FIG. 8A, 500 ml of the sample 100 is generally injected into the standard beaker 12. After that, the rotor 112 provided in the B-type viscometer 11 is inserted until the liquid level of the sample 100 is positioned between the immersion marks 111 provided in the B-type viscometer 11, and the measurement is started.

This test method is based on the assumption that the liquid sample 100 injected into the standard beaker 11 is a liquid showing a uniform concentration in the depth direction. Therefore, since a large gap is generated between the bottom of the standard beaker 12 and the tip of the rotor 112, the concentration changes in the height direction with the passage of time after being injected into the standard beaker 11 like the stabilizer 3. In the case of a material that is produced, it cannot always be said to be the optimum test method for measuring the apparent viscosity (B-type viscosity).

Therefore, in order for the guide rail 113 provided in the B-type viscometer 11 to insert the rotor 112 into the stabilizer 3 until it approaches the bottom of the standard beaker 12, the amount of the stabilizer 3 injected into the standard beaker 12 is 500 ml. Reduce more. For example, as shown in FIG. 8B, when the rotor 112 of the B-type viscometer 11 is inserted and the liquid level of the stabilizer 3 is positioned at the immersion mark 111, the amount of the stabilizer 3 becomes 450 ml. Is injected into the standard beaker 12.

In this way, since the rotor 112 of the B-type viscometer 11 is inserted close to the bottom of the standard beaker 12, the entire stabilizer 3 in the specified beaker 12 is uniformly agitated by the rotation of the rotor 112, and a more accurate apparent viscosity ( B-type viscosity) can be measured.

1 Underground hole 2 Hole wall 3 Stabilizer 4 Underground excavator 41 Conical part 42 Cylindrical part 43 Side cutter 5 Regeneration treatment device 51 Sediment separation device 52 Storage tank 53 Mixing device 6 Fluidization treatment soil 7 Groundwater 8 Underground concrete structure Object 81 Cast-in-place concrete pile 11 B-type viscometer 111 Immersion mark 112 Rotor 113 Guide rail 12 Standard beaker 100 Liquid sample

Claims (2)

When constructing a cast-in-place concrete underground concrete structure in an underground hole using a stabilizer
By measuring the apparent viscosity of the stabilizer while constructing the underground concrete structure, the measured apparent viscosity can be obtained in a timely manner.
A quality control method for a stabilizer that controls a deteriorated state due to agglutination of the stabilizer based on the measured apparent viscosity value and the apparent viscosity control value.
The apparent viscosity control value is
It is the apparent viscosity corresponding to the quality control standard value of the filtered water amount set based on the relationship between the filtered water amount and the apparent viscosity when the Ca component is mixed in the stabilizer before construction.
The apparent viscosity is based on the result of measuring the amount of filtered water together with the apparent viscosity using a stabilizer that fills the underground pores during construction and the relationship between the amount of filtered water and the apparent viscosity before construction. A quality control method for stabilizers, which comprises modifying the control value. In the quality control method for a stabilizer according to claim 1,
A quality control method for a stabilizer, wherein the apparent viscosity measured value is measured by a B-type viscosity measurement test.

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