JPH079094B2 - Quality control method in the stirring and mixing process of excavated soil and solidified material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is based on the in-situ soil agitation and mixing method, and
The present invention relates to a quality control method in a stirring and mixing step of excavated soil and a solidifying material when constructing a solidified body such as a solidified wall.

[Problems to be Solved by the Invention]

The in-situ soil agitation mixing method is to excavate the ground into a columnar or continuous columnar shape using an excavator and agitator, inject a solidifying agent water composition liquid such as cement milk into the excavation hole, stir and mix well, and excavate the excavated soil as an aggregate. This is a method of constructing solidified piles and solidified walls, but since the excavated soil in the ground and solidified material such as cement milk are agitated, problems such as homogeneity and continuity of solidified piles and solidified walls tend to occur. In the past, it has been desired to develop a quality control technique capable of confirming the degree of stirring and mixing at the time of performing stirring and mixing.

The present invention has been made in view of the above circumstances, and the object thereof is a mixing process of excavated soil and a solidifying material water composition liquid, while the mixing ratio of the excavated soil and the solidifying material is continuously detected. By stirring and mixing so that it becomes uniform, underground structures such as solidified piles and solidified walls with high homogeneity are being constructed.

[Means for Solving the Problems]

The quality control method in the stirring and mixing pipe step of the excavated soil and the solidifying material of the present invention includes vertically moving the excavator and agitator to inject the solidifying material water composition liquid into the excavation hole while excavating the ground, and solidify with the excavated soil. In the in-situ soil agitation mixing method of agitating and mixing with the material water composition liquid to construct a solidified body, the gamma ray density meter attached to the tip of the excavator stirrer allows the same depth as the gamma ray density meter in the excavation hole. The density of the surrounding excavated soil mixture is detected by measuring the scattered gamma dose scattered by the surrounding excavated soil mixture, and the content of the solidifying material in the surrounding excavated soil mixture is calculated from the density, and the surrounding excavation is performed over the entire length of the drilled hole. It is characterized in that the elevation of the excavator and agitator and the measurement of the scattered gamma dose are continued so that the solidified material content in the soil mixture becomes uniform.

When a solidifying material water composition liquid using water such as cement milk as a medium is injected into the excavated soil, the density of the obtained mixture of the excavated soil and the solidified material has a density different from the ground density before excavation,
Generally, it has a value lower than the ground density. Then, the density also changes in accordance with the change in the mixing ratio. Therefore, if the density of the target ground before excavation and the density of the mixture corresponding to each mixing ratio of the excavated soil / solidifying material water composition liquid mixture are known in advance, the excavated soil / solidified material in the excavation hole of the target ground By detecting the density of the mixture, the content of the solidifying material in the excavated soil / solidifying material mixture can be calculated.

In the quality control method of the present invention, a gamma ray source (for example, ⁶⁰ C
o), a gamma ray detector (for example, Geiger-Muller counter (hereinafter referred to as GM counter), scintillation counter, Ge (Li) detector, etc.) and a gamma-ray densitometer equipped with a preamplifier. To use.

Using this excavator and agitator, gamma rays emitted from the radiation source are emitted in the process of injecting the solidifying material water composition liquid into the excavation hole while excavating the ground, and stirring and mixing the excavated soil and the solidifying material water composition liquid. The gamma dose that reaches the detector after being scattered by the surrounding excavated soil / solidifying material mixture is measured, and the density of the surrounding excavated soil / solidifying material mixture is detected from the dose. Since the correlation between the density of the excavated soil / solidified material mixture and the content of the solidified material in the excavated soil / solidified material mixture is obtained in advance, it is possible to immediately perform excavation by detecting the density of the excavated soil / solidified material mixture. soil·
The content of the solidifying material in the solidifying material mixture can be known.
Therefore, the content of the solidifying material in the excavated soil / solidifying material mixture at each depth can be immediately grasped along the vertical movement of the excavator and agitator over the entire depth. Based on this measurement result, when a depth that does not fall within the prescribed content range is encountered during one round of excavation / injection / stirring / mixing, the excavator / stirring machine is repeatedly moved up and down to reach the depth content. Within the prescribed content range. Repeating this kind of operation, uniform excavated soil
A solidifying material mixture is obtained, so that solidified piles and solidified walls of uniform quality can be constructed. In addition, if there is a variation in the solidifying material content after one round of excavation / injection / stirring and mixing, and there is a portion where the content does not fall within the prescribed content range, the excavator / mixer is re-extracted at that portion. It is also possible to take a method of lowering and mixing again with stirring until the upper and lower parts of the part fall within a predetermined content range. Which method is used is appropriately selected depending on the situation of the construction site,
The former is generally preferred.

The method of injecting the solidifying material water composition liquid is (1) starting at the start of excavation, injecting half the amount while excavating to the deepest part, and injecting the remaining half amount while the excavator stirrer is being pulled up, (2)
Ordinary methods such as starting at the start of excavation and completing injection at the time of excavation to the deepest part, (3) starting at the time of excavation to the deepest part and completing when pouring while continuing to raise the excavator and agitator Any method that employs the in-situ soil agitation mixing method may be adopted. Also,
Although it is not preferable if a portion where the solidifying material content is too small is found, the solidifying material water composition liquid may be additionally injected when stirring and mixing for homogenization.

Thus, in the present invention, since it is possible to stir and mix the excavated soil and the solidifying material while continuously checking the solidifying material content during construction, it is possible to take measures in real time according to the solidifying material content, Highly accurate and reliable construction, and
Wasteful work can be reduced and construction efficiency can be improved.

In the present invention, by detecting the density of the excavated soil mixture by measuring the scattered gamma dose, the density of the excavated soil mixture-solidifying material content in the excavated soil mixture is indirectly calculated. Is required to be a ground having a density relatively different from the density of the excavated soil / solidifying material water composition liquid. That is, if only the excavated soil in the excavation hole is examined, the original ground is excavated and agitated, so the density is generally smaller than the original soil, but the excavated soil is injected with the solidifying agent water composition liquid and agitated. This is because it cannot be said that the density of the mixed excavated soil / solidifying material water composition liquid is always smaller than that of the original ground. Unfortunately, the present invention cannot be applied to the ground whose density is close to that of the excavated soil / solidifying material water composition liquid.

Whether the ground to which the present invention can be applied is determined by inserting a radiation measuring pipe into the target ground as a preliminary experiment and inserting the same gamma-ray density meter as the gamma-ray density meter used in the present invention to measure the ground density over the entire depth. On the other hand, the density of the excavated soil / solidifying material water composition liquid is calculated on the assumption that the present invention is applied, and it is determined by determining whether or not there is a significant difference between the densities of the two.

〔Example〕

(1) Preliminary Experiment (a) Inserting a radiation measuring pipe in the target ground in advance, inserting a gamma-ray density meter to measure the scattered gamma-ray count rate (counting ratio) of the ground, and obtaining the ground density. Confirm that the ground is applicable.

(B) Add the solidifying material water composition liquid to the excavated soil of the target ground,
Mix with stirring to make a mixture, and then mix the mixture with an inner diameter of 700 mm,
The height is 1300 mm, and the radiation measuring pipe with an inner diameter of 54 mm along the central axis is placed in the form, the gamma-ray density meter is inserted in the pipe, and the scattered gamma-ray counting rate (counting ratio) is measured. To grasp the correlation between the mixing ratio of excavated soil and the solidified water composition liquid of a predetermined concentration and the gamma ray counting rate (counting ratio). At the same time, the density range of the mixture of the excavated soil and the solidifying material water composition liquid required for constructing a good solidified body, that is,
Determine the required gamma ray count rate (counting ratio) range.

(2) On-site construction As shown in Fig. 1, the ground 1 is continuously excavated in a cylindrical shape with a diameter (D) of 550 mm and a depth (H) of 12000 mm, and the excavated soil and the solidified material are mixed at the original position to stop the water. Built wall 2 The drilling stirrer 3 shown in FIG. 2 was used for the construction. The excavation stirrer 3 has a grout (solidified material water composition liquid) injection hole 4, a bit 5 and excavated soil stirring blade 6 at the tip, and a gamma ray source 7, a lead shielding material 8 and a GM counter tube 9 inside the rotating shaft. A gamma-ray densitometer 11 including a preamplifier 10 is housed. A counting device (not shown) connected from the gamma ray densitometer 11 to the cable 12 is mounted on the traveling carriage 13.

The excavation stirrer 3 is vertically descended to start excavation of the ground 1. Simultaneously with the start, a solidifying material water composition liquid having a predetermined concentration is injected from the grout injection hole 4 to stir the excavated soil and the solidifying material with the stirring blades 6.
Continue the excavation while mixing with stirring. The injection rate is controlled so that half of the predetermined amount of the solidifying material water composition liquid is injected by the time of completion of excavation. After reaching the deepest portion, while raising the excavation stirrer 3, the injection of the solidifying material water composition liquid from the grout injection hole 4 and the stirring and mixing by the stirring blade 6 are continued. When the excavation stirrer 3 is started to be pulled up, the gamma ray density meter 11 stored in the rotating shaft scatters the surrounding excavated soil / solidifying material mixture at the same height as the gamma ray density meter 11 and scatters the gamma rays. (Counting ratio) is continuously read by the counting device on the carriage 13.

While confirming whether the measured gamma ray count rate (counting ratio) is within the range of the gamma ray count rate (counting ratio) determined by the preliminary experiment, the injection of the solidifying material water composition liquid and the stirring and mixing are continued. If it is out of the range, the excavation stirrer 3 is moved up and down little by little at that portion, and the upper and lower parts are stirred and mixed to be within the range. While repeating this operation, the excavation stirrer 3 is pulled up to the upper end, and the work is completed.

The gamma-ray count ratio is the ratio of the measured gamma-ray count rate to the gamma-ray count rate measured for the standard substance, and is used to eliminate the effect of the decay of radioactivity over time of the gamma-ray source. It is a measure. Therefore, when a radiation source having a long half-life is used and measurement is completed within a relatively short time, there is no great difference whether the scale of the counting rate or the counting ratio is used.

When the injection of the solidifying material water composition liquid is started at the start of the excavation and is completed at the time of excavation to the deepest part, the excavation stirrer 3 is vertically lowered to start excavation of the ground 1, and At the same time, the solidifying material water composition liquid having a predetermined concentration is injected from the grout injection hole 4, and the excavation is advanced while stirring and mixing the excavated soil and the solidifying material with the stirring blades 6, and a predetermined amount of the solidifying material water composition liquid is obtained by the completion of the excavation. Control the infusion rate as infused.

During this time, the gamma ray density meter 11 stored in the rotating shaft shows the gamma ray count rate (counting ratio) scattered on the surrounding excavated soil / solidifying material mixture at the same height as the gamma ray density meter 11 on the carriage 13. The excavation is continued while confirming whether the gamma ray count rate (counting ratio) measured by reading continuously with the counting device is within the range of the gamma ray count rate (counting ratio) determined by the preliminary experiment. If it is out of the range, the excavation stirrer 3 is repeatedly moved up and down at that portion to stir and mix the upper and lower parts to bring it into the range. After reaching the deepest part, while stirring the excavation stirrer 3, the stirring blade 6 continues stirring and mixing. Even during this pulling up, the gamma ray count rate (counting ratio) of the excavated soil mixture at each site was measured and the gamma ray count rate (counting ratio) was measured.
Is within the specified range.

Fig. 3 shows the gamma-ray count ratio along the vertical direction when the ground was excavated in a columnar shape, and the method of injecting a prescribed amount of half amount of the solidifying material water composition liquid solidifying material by the time of the completion of the excavation, and the preliminary experiment Shows the gamma-ray count ratio of the ground measured before construction. The gamma-ray densitometer has a count ratio of 0, which is the target value over the entire depth.
It can be confirmed that the solidifying material water composition liquid was uniformly stirred and mixed so as to be stored in the vicinity of 1. The ground 1 before construction is a high-density ground, and it is shown that the density of the excavated soil / solidifying material mixture was clearly reduced by excavation, injection of the solidifying material water composition liquid, and stirring and mixing.

〔The invention's effect〕

The present invention is as described above. Since the excavated soil and the solidifying material can be stirred and mixed while continuously checking the solidifying material content during construction, take measures to make the solidifying material content uniform in real time. It is possible to improve the construction accuracy and reliability, reduce wasteful work, and improve the construction efficiency. Therefore, it is possible to efficiently construct an underground structure having good homogeneity.

[Brief description of drawings]

The drawings show examples, and FIG. 1 is a plan view and a vertical sectional view of a water blocking wall, and FIGS. 2 (a) and 2 (b) are side views of a drilling agitator and a partial cross section of a tip portion thereof. An enlarged view and FIG. 3 are graphs of the gamma-ray count ratio of the ground and excavated soil / solidifying material mixture before and after construction of the water blocking wall. 1 ... Ground, 2 ... Water stop wall, 3 ... Excavator and agitator, 4 ...
Grout injection hole, 5 ... Bit, 6 ... Excavated soil stirring blade, 7 ... Gamma ray source, 8 ... Lead shielding material, 9 ... GM counter, 10 ... Preamplifier, 11 ... Gamma ray density meter , 12 …… Cable, 13 …… Truck.

Claims (1)

[Claims] 1. A soil-solidified body in which a drilling stirrer is moved up and down in a vertical direction to inject a solidifying material water composition liquid into a drilling hole while excavating the ground, and stirring and mixing excavated soil and a solidifying material water composition liquid. In the in-situ soil agitation mixing method, the gamma-ray densitometer attached to the tip of the excavator stirrer is used to measure the scattered gamma dose scattered or scattered by the surrounding excavated soil mixture at the same depth as the gamma-ray densitometer in the drill hole. To detect the density of the surrounding excavated soil mixture, calculate the content of the solidifying material in the surrounding excavated soil mixture from the density, and make the content of the solidified material in the surrounding excavated soil mixture uniform over the entire length of the drill hole. A quality control method in a stirring and mixing process of excavated soil and solidified material, which comprises continuously moving the excavator and agitator and measuring the scattered gamma dose.