JPH11222844A - Measuring system and measuring method of prepared improved body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the preparation range of an improved body with high reliability without conducting experiment works. SOLUTION: The measuring system 1 of the prepared improved body has a casing 3, in which an injection pipe 2 can be inserted into a hollow section, annular electrodes 41 , 42 ,...4n installed onto the external surface of the casing along the axis of a member of the casing, a Dc power 6 and a voltmeter 7 electrically connected to the electrodes through a changeover instrument 5 as a changeover means and an arithmetic and control section 8 controlling these each equipment. The changeover instrument 5 can select desired electrodes in the electrodes 41 , 42 ,...4n as current electrodes 4a, 4b and potential electrodes 4c, 4d. Electricity is conducted through the improved body 11 prepared around the casing 3 by operating the DC power 6 and applying voltage between the current electrodes 4a, 4b by the arithmetic and control section 8 while potential difference between the potential electrodes 4c, 4d is measured and the prepared range of the improved body 11 is evaluated from the relationship of potential difference and a conducted current value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system and a measuring method for measuring a ground improvement body formed in a ground by a hardening agent injected into the ground.

[0002]

2. Description of the Related Art As a ground improvement method for improving soft ground, there is a chemical liquid injection method in which a hardener is injected into the ground. Among such methods, a so-called high-pressure injection in which the hardener is stirred and injected into the ground by high-pressure injection. A stirring method is known.

In this method, a predetermined hardening agent is injected into the ground by rotating a spray nozzle at a high pressure to inject the hardening agent into the ground, and the injection energy is used to cut the ground and mix it with the ground. Stirring is performed, and according to this method, a pile-shaped improved body can be formed in soft ground.

By the way, after the ground improvement is performed by the high-pressure injection stirring method, it is checked whether the size of the improved body actually constructed, in other words, the range in which the ground improvement has been performed is as intended. It is an important matter in the ground improvement work, but as a confirmation method, rather than a measurement method using elastic waves, ultrasonic waves, etc., a test work is performed before this work, and it is created by the test work. It is common practice to employ a method of directly measuring the diameter of the improved body by digging around it.

[0005]

The measuring method by such a test construction has an advantage that the reliability of the measurement data is higher than the method by the elastic wave or the like, but on the other hand, the test construction must be performed separately from the main construction. For this reason, there has been a problem that it is disadvantageous in terms of construction period and cost. In addition, there are also problems such as the fact that the test site cannot be performed due to the small size of the site, and that the geological structure of the place where the test work is performed and the site where the main work is performed do not always match.

The present invention has been made in view of the above circumstances, and provides a measurement system and a measurement method of a construction improvement body capable of obtaining highly reliable data without performing test work. Aim.

[0007]

In order to achieve the above object, a measuring system for an improved structure according to the present invention is defined in claim 1.
As described in the above, a casing through which the injection pipe can be inserted into the hollow interior, a pair of current electrodes attached to the outer surface of the casing, a power supply electrically connected to the pair of current electrodes, and an outer surface of the casing. It has a plurality of potential electrodes attached thereto and a voltmeter electrically connected to the potential electrodes.

[0008] Further, the measuring system of the improvement body according to the present invention is arranged such that a large number of electrodes are arranged on the outer surface of the casing along a material axis thereof, and the electrodes are connected to the power supply and the voltmeter via predetermined switching means. And the switching means is configured to be able to arbitrarily select a desired electrode among the electrodes as the pair of current electrode and the potential electrode.

Further, the measuring system of the improved construction according to the present invention includes an arithmetic control unit for controlling the power supply, the voltmeter and the switching means, and controls the arithmetic control unit by controlling the switching means. A predetermined electrode among the electrodes is electrically connected to the power supply and the voltmeter, respectively, to form a current electrode and a potential electrode. In such a state, the power supply is operated to apply a voltage between the current electrodes, and the surroundings of the casing. And a potential difference between the potential electrodes is measured, and a development range of the improved body is evaluated based on a relationship between the potential difference and a value of a current flowing through the improved body.

According to a fourth aspect of the present invention, there is provided a method for measuring a construction improvement body, wherein a hardening agent is inserted into a ground by pressing a casing into the ground and rotating an injection pipe inserted into a hollow space in the casing. To form an improved body around the casing, and apply a voltage between a pair of current electrodes attached to the outer surface of the casing to energize the improved body. The potential difference between a pair of potential electrodes attached to the device is measured, and the creation range of the improved body is evaluated from the relationship between the measured potential difference and the value of the current flowing.

In the measuring system and the measuring method of the improvement body according to the present invention, first, the improvement body to be measured is formed in the ground in advance. That is, by inserting a casing into the ground or tunnel inside the ground to be improved and injecting a curing agent while rotating an injection pipe inserted into the hollow space in the casing as necessary, the periphery of the casing is A pile-shaped improved body is formed.

[0012] When the improved body is constructed in this way, a power supply is operated to apply a voltage between the pair of current electrodes, and a current flows around the casing. Then, a potential difference between the potential electrodes attached to the outer surface of the casing is measured by a voltmeter in such an energized state. Such measurement is repeated a plurality of times by appropriately changing the positions and intervals of the current electrodes and the potential electrodes as needed.

Next, the specific resistance and the thickness of the substance spreading around the casing are analyzed from the relationship between the measured potential difference and the value of the supplied current, and based on the results of the analysis, the improvement range of the improved body, for example, Evaluate its diameter.

On the other hand, after the measurement is completed, the secondary injection is performed while pulling out the casing, or the casing is buried without being pulled out, and the secondary injection is performed in the hollow portion in the casing to complete the ground improvement. I do.

The power supply only needs to be able to pass a direct current, but a method of switching the polarity of the power supply at a cycle long enough to be regarded as a direct current to obtain a square wave (alternating direct current) may be used.

The arrangement of the current electrode and the potential electrode is arbitrary. For example, there is a method of arranging a plurality of potential electrodes on a straight line between a pair of current electrodes. Along with arranging a large number of electrodes along the electrodes, the electrodes are electrically connected to the power supply and the voltmeter via predetermined switching means, and the switching means is connected to a desired one of the electrodes by the pair of current electrodes and the If a potential electrode can be selected arbitrarily, the current electrode and potential electrode can be switched instantaneously to reduce the time required for measurement preparation, and as a result, a large number of measurements can be executed in a short time Becomes possible. Further, the measurement accuracy of the improved body is improved as much as the number of measurements can be increased.

The operation of the switching means and the measurement of the voltmeter may be directly performed by the measurer himself. However, in addition to this configuration, an arithmetic control unit for controlling the power supply, the voltmeter and the switching means is provided. The arithmetic and control unit controls the switching means to electrically connect a predetermined electrode of the electrodes to the power supply and the voltmeter, respectively, as a current electrode and a potential electrode. Is operated to apply a voltage between the current electrodes, to supply current to the improved body formed around the casing, and to measure a potential difference between the potential electrodes, from the relationship between the potential difference and the value of the supplied current. If configured to evaluate the creation range of the improved body, a series of operations such as selection and switching of electrodes, operation of a power supply, setting of energization time, measurement of a potential difference, and evaluation of the creation range of the improved body are automated. It becomes possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a measurement system and a measurement method for an improved structure according to the present invention will be described with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

FIG. 1 is an overall view of a measurement system for a developed and improved body according to this embodiment. As can be seen from the figure, a measurement system 1 for an improved construction according to the present embodiment has a casing 3 through which an injection pipe 2 can be inserted into a hollow interior, and an annular shape attached to the outer surface thereof along the material axis of the casing. Electrode 4
₁ , 4 ₂ , 4 ₃ ,..., 4 _n , a DC power supply 6 and a voltmeter 7 electrically connected to the electrodes via a switching device 5 as switching means, and arithmetic control for controlling these devices Unit 8.

The injection pipe 2 is supplied to a chemical tank (not shown) or a compressor (not shown) so that a slurry such as cement or a hardening agent such as a water glass-based chemical can be injected from an injection port 9 formed at the tip (the lower end in the figure). Connected.

The casing 3 is made of, for example, hard vinyl chloride,
FRP, although it is preferable to constitute a non-conductive member such as precast concrete, electrodes _{4 1, 4 2, 4 3} , ···· 4 n
In addition, as long as electrical non-contact with the surrounding formed body is ensured, a conductive steel tube or the like may be used.

The DC power supply 6 is only required to be able to pass a DC current, but can output a rectangular wave (alternating DC) by switching the polarity of the power supply in a cycle long enough to be regarded as DC. May be.

The switching device 5, under control of the arithmetic and control unit 8, the electrode 4 _1, 4 _2, 4 _3, of · · · · 4 _n, the desired 2
One electrode is selected as a pair of current electrodes 4a and 4b, and of the remaining electrodes, a desired electrode, for example, two electrodes arranged between the pair of current electrodes 4a and 4b are set as potential electrodes 4c and 4d. You can choose.

The arithmetic and control unit 8 controls the switch 5 to electrically connect the pair of current electrodes 4a and 4b to the DC power source 6 and electrically connect the pair of potential electrodes 4c and 4d to the voltmeter 7, respectively. Activate the DC power source 6 with the current electrode 4
By applying a voltage between a and 4b, the improved body 11 formed around the casing 3 is energized as shown in FIG. 2, and furthermore, a potential difference between the potential electrodes 4c and 4d is measured and the potential difference is measured. Improved body 11 based on the relationship with the current value
Can be evaluated.
The arithmetic control unit 8 can be constituted by, for example, a personal computer.

In the measurement system 1 and the measuring method of the improved structure according to the present embodiment, first, the improved object 11 to be measured is formed in the ground in advance. That is, FIG.
As shown in the figure, the casing 3 is rotationally press-fitted into the ground 21 to be ground-improved, and at the same time, the curing agent is supplied from the outlet 9 provided at the lower end thereof while rotating the injection pipe 2 inserted into the hollow space in the casing. By injecting into the ground 21, the soil around the casing 3 and the hardening agent are stirred and mixed, and the pile-shaped improved body 11 is sequentially formed from above to below.

Next, when the improved body 11 as shown in FIG.
A voltage is applied between a and 4b to energize the improved body 11 formed around the casing 3. Then, a potential difference between the potential electrodes 4c and 4d is measured with a voltmeter in such a current-carrying state. Such measurement is performed by the switch 5 using the current electrodes 4 a and 4 b and the potential electrode 4.
Repeat as many times as necessary while changing c and 4d.

Next, the specific resistance and the thickness of the substance spreading around the casing 3 are analyzed from the relationship between the measured potential difference and the value of the supplied electric current, and the forming range of the improved body 11 is determined based on the analysis result. In particular, its diameter R is evaluated.

More specifically, the positions or intervals of the current electrodes and the potential electrodes are changed in various ways to measure the respective potential differences and the current value that was being energized at that time, and to compare the potential values using the measured values. Calculate the resistance. Then, the principle of the specific resistance method, that is, if the distance between the current electrodes is small, the underground structure near the electrode is greatly reflected in the specific resistance, and if the distance between them is wide, the distant underground structure affects the specific resistance. By applying the principle, the underground structure around the casing 3 and, consequently, the creation range of the improved body 11 are evaluated.

Here, the selection and switching of the current electrodes 4a and 4b and the potential electrodes 4c and 4d, the operation of the DC power supply 6,
A series of operations such as setting of the energization time, measurement of the potential difference in the voltmeter 7, and evaluation of the creation range of the improved body 11 are preferably performed by the arithmetic and control unit 8.

If the relationship between the construction range of the improved body and the specific resistance is previously derived by analysis and stored in the storage device of the arithmetic and control unit 8 in the form of a database, the measured and calculated values can be obtained on site. Improved body 1 by inputting specific resistance
It is also possible to instantly evaluate the creation range of No. 1.

After the measurement is completed, before the improved body 11 is completely hardened by the action of the hardening agent, the casing 3 is pulled out and the secondary injection is performed, or the casing 3 is filled without being pulled out, and A secondary injection is performed in the hollow part of, and the ground improvement is completed.

As described above, according to the measurement system and the measurement method of the developed and improved body according to the present embodiment, the electric prospecting is performed by using the principle of the so-called resistivity method.
As we evaluated the creation range of the created improved body, with higher accuracy than conventional elastic wave exploration and ultrasonic exploration,
Moreover, it is possible to efficiently evaluate the creation range of the improved body without having to install a transmitting / receiving device for elastic waves or ultrasonic waves.

In addition, since it is not necessary to carry out a test work separately from the main work as in the prior art, it is possible to greatly reduce the construction period and cost of the entire ground improvement work, and
In other words, unlike the test work, which was only intended for the test specimen, the construction range of the improved body of this construction can be evaluated nondestructively and immediately after the injection of the curing agent. If it is clear that the size is smaller than that, it is also possible to take measures such as re-injecting the curing agent, and it is possible to greatly improve the construction quality of the ground improvement work.

In addition, according to the measurement system for the improved structure according to the present embodiment, a large number of electrodes 4 ₁ , 4 ₂ , 4 ₃ ,..., 4 _n are arranged on the outer surface of the casing 3 along the material axis. electrically connected to a DC power supply 6 and the voltmeter 7 through the switching device 5 to the electrode as well as, the sections exchangers, electrodes 4 _1, 4 _2, 4 _3, ·
... Of 4 _n , desired electrodes are connected to a pair of current electrodes 4 a, 4 a
b and the potential electrodes 4c and 4d can be arbitrarily selected, so that the current electrode and the potential electrode are switched instantaneously to shorten the time required for measurement preparation, and as a result, a large number of measurements can be shortened. It is possible to execute in time. Furthermore, the measurement accuracy of the improved body 11 is improved because the number of measurements can be increased.

Further, according to the measurement system of the improved construction according to the present embodiment, the switch 5 is controlled to control the electrodes 4 ₁ , 4 ₂ ,
4 _3, ···· 4 _n predetermined electrode DC power supply 6 and the voltmeter 7 and the current electrode 4a each electrical connection of, 4b, potential electrodes 4c, and 4d, the DC power supply 6 in this state When activated, a voltage is applied between the current electrodes 4a and 4b to energize the improved body 11 formed around the casing 3 and the potential difference between the potential electrodes 4c and 4d is measured. , The construction range of the improved body 11 is evaluated based on the relationship between the electrodes 4 ₁ , 4 ₂ , 4 ₃ ,.
4 _n selection and switching, operation of DC power supply 6, setting of energization time, measurement of potential difference in voltmeter 7, and improved body 11
It is possible to automate a series of operations such as the evaluation of the creation range of a building.

Although not specifically mentioned in the present embodiment, the progress of the curing of the improved body 11 by the action of the curing agent and the timing of the measurement of the specific resistance described above are not described.
It is sufficient to judge whether or not the formation range can be grasped more clearly, and it may be measured before curing or after curing according to the local situation. Also, if the specific resistance is measured continuously as the curing progresses,
It is also possible to grasp which region of the improved body 11 is cured first.

In this embodiment, the present invention has been described as an example in which the present invention is applied to a ground improvement method. In addition, as shown in FIG. When the presence of the cavity 32 is confirmed in front of the face 31, grout 33 may be injected into the cavity in advance in order to prevent collapse of earth and sand due to excavation. When measuring the formation area of the grout 33, The present invention can also be applied to

That is, as shown in the figure, the grouting machine 36 has the same switching device 5, DC power supply 6,
A control device 37 containing a voltmeter 7 and an arithmetic control unit 8 is installed, and the DC power supply 6 and the voltmeter 7 are connected to the electrodes 4 ₁ , 4 ₂ , 4 ₃ ,..., 4 _n are electrically connected.

In performing the measurement, first, the cavity 32
The casing 35 is inserted into the casing and grout is injected from the tip through an injection pipe into the casing. Thereafter, the potential difference is measured in the same procedure as in the present embodiment, and the relationship between the potential difference and the current value at that time is measured. What is necessary is just to calculate the specific resistance and measure the formation range of the grout 33.

In the present embodiment, the switching unit 5, the DC power supply 6, and the voltmeter 7 are controlled by the arithmetic control unit 8, and the obtained measurement data is analyzed by the arithmetic control unit. However, the measurer may operate each device by himself / herself and record and analyze the measured value by himself / herself.

In this embodiment, the switch 5 is provided so that the positions and intervals of the current electrode and the potential electrode can be changed. However, for example, by referring to an analysis result performed in advance, measurement at a specific position is performed. If the formation range of the improved body 11 can be specified using only the specific potential calculated from the obtained potential difference and the current value at that time, a total of four electrodes of a pair of current electrodes and a pair of potential electrodes are sufficient. However, the switch 5 is unnecessary.

[0042]

As described above, according to the measurement system for the improved structure of the present invention according to the first aspect, the accuracy of the elastic wave or ultrasonic wave is higher than that of the conventional elastic wave or ultrasonic wave exploration. It is possible to efficiently evaluate the creation range of the improved body without the need to install the receiving / transmitting device.

Further, according to the measuring system for an improved structure of the present invention according to the second aspect, the current electrode and the potential electrode are switched instantaneously to shorten the time required for measurement, and as a result, a large number Measurement can be executed in a short time. Furthermore, the effect of improving the measurement accuracy of the improved body is also provided because the number of measurements can be increased.

According to the measuring system of the improved structure of the present invention, the selection and switching of the electrodes, the operation of the power supply, the setting of the energizing time, the measurement of the potential difference in the voltmeter, and the range of forming the improved structure. There is also an effect that it is possible to automate a series of operations such as the evaluation of the information.

Further, according to the measuring method of the improved structure of the present invention according to the fourth aspect, a receiving and transmitting device for elastic waves and ultrasonic waves is installed with higher accuracy than the conventional elastic wave exploration and ultrasonic exploration. It is possible to efficiently evaluate the creation range of the improved body without troublesome work.

[0046]

[Brief description of the drawings]

FIG. 1 is an overall view of a measurement system for a developed and improved body according to an embodiment.

FIG. 2 is a cross-sectional view showing the operation of the measurement system for the land improvement body according to the embodiment.

FIG. 3 is a cross-sectional view showing a procedure for forming an improved body prior to the method of measuring the improved body according to the embodiment.

FIG. 4 is an overall view showing an example in which a measurement system for a land improvement body according to the present embodiment is applied to a tunnel grout.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS ₁ Measurement system of improvement body 2 Injection pipe 3 Casing 4 ₁ , 4 ₂ , 4 ₃ ,... 4 _n electrode 4 a, 4 b Current electrode 4 c, 4 d potential electrode 5 Switch (switching means) 6 DC power supply (power supply) 7) Voltmeter 8 Operation control unit 11 Improved body

Claims (4)

[Claims] 1. A casing through which an injection tube can be inserted into a hollow interior, a pair of current electrodes attached to an outer surface of the casing, a power supply electrically connected to the pair of current electrodes, and an outer surface of the casing. A plurality of potential electrodes provided and a voltmeter electrically connected to the potential electrodes. 2. A plurality of electrodes are arranged on the outer surface of the casing along a material axis thereof, and the electrodes are electrically connected to the power supply and the voltmeter via predetermined switching means. 2. The measurement system according to claim 1, wherein a desired electrode is arbitrarily selectable as the pair of current electrode and the potential electrode. 3. 3. An arithmetic control unit for controlling the power supply, the voltmeter and the switching means, wherein the arithmetic control unit controls the switching means to cause a predetermined electrode among the electrodes to be connected to the power supply. A current electrode and a potential electrode are electrically connected to a voltmeter, respectively, and in this state, the power supply is operated to apply a voltage between the current electrodes to energize the improved body formed around the casing, and to apply the potential to the improved body. 3. The measuring system for an improved improved body according to claim 2, wherein a potential difference between the electrodes is measured, and a creation range of the improved body is evaluated based on a relationship between the potential difference and a value of a supplied current. 4. An improved body is formed around the casing by pressing a casing into the ground and injecting a hardening agent while rotating an injection pipe inserted into a hollow space in the casing to form an improved body around the casing. A voltage is applied between the attached pair of current electrodes to energize the improved body, and a potential difference between the pair of potential electrodes attached to the outer surface of the casing is measured in the energized state, and the measured potential difference and the energized current are measured. A method for measuring the formation range of the improved body based on a relationship with the current value.