JP3880327B2 - Judgment method and apparatus for stability of underground structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a technical field of a determination method and a determination device for the stability of an underground structure that is built near a seabed or a shore, such as a submarine structure such as a submarine tunnel, and where there is water leakage including seawater in the groundwater. Belongs to.
[0002]
[Prior art]
Today, underground structures such as tunnels and box culverts are often built below the groundwater surface and the sea level, and such underground structures often do not allow natural drainage of leaked water. At this time, in order to avoid submergence of the underground structure, it is required to artificially discharge the leaked water to the ground using power. In such underground structures, it is assumed that the stability of the underground structure will decrease due to deterioration of the underground structure itself due to erosion by seawater, and such a decrease in stability will be left as it is. If this is done, there is a risk of flooding with a large amount of seawater, and early repairs are required.
[0003]
[Problems to be solved by the invention]
For this reason, it is advocated that periodic inspections of stability be made for such underground structures. However, it is practically difficult to simplify such a determination test. In order to do this, there is a problem that expensive inspection equipment and a large number of workers are required, and it takes a long time for the determination, and there is a problem to be solved by the present invention.
[0004]
[Means for Solving the Problems]
The present invention has been created in view of the above-described circumstances for the purpose of solving these problems, and the invention of claim 1 is directed to an underground structure having water leakage including seawater in groundwater. In determining stability, when the normal concentration of seawater components in the leaked water is measured and this change state is obtained in advance as basic data, and when the concentration of seawater components deviating from the basic data is measured, This is a method for determining the stability of an underground structure, characterized in that it is determined that the stability of the underground structure has decreased.
The invention according to claim 2 is a data storage means for storing, as basic data, a measured value of the normal concentration of seawater components in the leaked water in determining the stability of the underground structure having water leakage including seawater in the groundwater, Concentration measuring means for measuring the concentration of seawater components, and when the concentration of seawater components measured by the concentration measuring means deviates from the stored basic data, the stability of the underground structure has decreased. An apparatus for determining the stability of an underground structure, characterized by comprising a stability determination means for determining that there is a thing.
In this way, if the concentration of seawater components at normal times is obtained as basic data, the concentration of seawater components deviating from this basic data can be easily measured and the stability of underground structures can be easily determined. The degree can be determined, and the determination work can be simplified and made more efficient.
The invention of claim 3 can be characterized in that , in claim 2 , the basic data is data measured throughout the year, and in this way, determination throughout the year is possible. .
The invention of claim 4 is characterized in that, in claim 2 or 3 , the seawater component whose concentration is measured is a sodium ion, and in this case, the seawater component has a high concentration. Can be determined, and the reliability of determination accuracy can be improved.
The invention of claim 5 is that in claim 2, 3 or 4 , when measuring the basic data, the flow rate of the leakage water is also measured, and the measured leakage flow rate deviates from the normal leakage water flow rate. The measured concentration of seawater components measured at that time is not used as basic data. The stability of underground structures with high accuracy can be determined.
The invention of claim 6 is the invention according to claim 2, 3, 4 or 5, wherein when determining the stability of the underground structure, the flow rate of the leaked water is also measured, and the measured leaked water flow rate is normal. When it is judged that the water flow rate is deviated from the water flow rate, the measured concentration value of the seawater component was not used as the measured value for judging the stability of the underground structure. In such a case, in making the stability determination, it is possible to reduce the determination error when there is a specific fluctuation in the groundwater flow rate and to improve the reliability of the determination. .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Focusing on the leakage of water containing seawater into the groundwater in underground structures built near the ocean floor and the coast, measure the concentration of chemical components derived from seawater and use it as basic data. It was confirmed that the stability of the underground structure can be determined by observing the concentration state of chemical components derived from seawater in the sea, and the present invention was completed. In this case, the underground water in the leaked water is subject to seasonal fluctuations due to the natural environment, such as the weather, while the seawater inflow route from the seabed or coast to the underground structure is formed for the seawater. As long as there is no exceptional situation such as an earthquake, it is considered that there is no change or slight change even if there is a change, so it is estimated that it is almost constant throughout the year regardless of the season Therefore, the seasonal fluctuations of the concentration of water leakage composition components are measured in advance and converted into data as basic data for the year, and this is compared with the actually measured concentration of water leakage composition components to stabilize the underground structure. The degree can be inspected throughout the year.
And in this invention, when the sodium ion concentration which is one of the seawater components and the water leakage flow rate were measured over a plurality of years with respect to the water leakage of a certain submarine tunnel, the measurement position was the same although there was a specific difference depending on each measurement position. If there is, the seasonal change is found to be almost constant, and this is used as basic data for one year. When the sodium ion concentration deviates from this basic data (deviation in a large direction), It can be presumed that the stability is lowered, and the present invention is completed here. For such basic data, the reliability increases as the measurement values of many years are accumulated. Therefore, the measurement values when the stability is judged to be high, that is, the normal state, are sequentially accumulated. It is preferable to update this as basic data.
[0006]
For example, sodium ions (Na ⁺ ), potassium ions (K ⁺ ), magnesium ions (Mg ²⁺ ), calcium ions (Ca ²⁺ ), etc. This is performed by selectively measuring one or more concentrations of anions such as (Cl ⁻ ) and sulfate ions (SO ₄ ²⁻ ). A preferable seawater component for measuring the concentration needs to be a component that is contained in a large amount in seawater and is chemically stable, and suitable examples thereof include sodium ions or chloride ions. That is, these seawater components are also contained in the groundwater, but the determination error decreases as the difference in content increases.
Furthermore, when implementing this invention, in order to improve a precision more, it cannot be overemphasized that it can determine about a multiple types of content component instead of determining about one type of sodium ion.
[0007]
Furthermore, when the groundwater in the leaked water is abnormally heavy due to, for example, a typhoon or when there is an abnormally low amount of rain due to drought or the like, the amount of groundwater varies greatly and may not be the year-round groundwater flow rate. The concentration of seawater components at this time also deviates from the year-round concentration, and determining stability based on this will impair the reliability of stability determination. Therefore, when creating basic data and determining stability, if it is determined that the groundwater flow rate deviates from the basic data, the concentration of seawater components measured together is not adopted as basic data. In addition, it is preferable not to use the measured value when the stability determination is performed, thereby increasing the reliability of the stability determination.
[0008]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a schematic longitudinal sectional view of a conventional submarine tunnel, and FIG. 1B is a schematic transverse sectional view. The submarine tunnel includes an upstream main shaft 1, a downstream main shaft 2, and a working shaft. 3 of three. The main shafts 1 and 2 of the upper and lower lines are constructed in a substantially V-shaped inclined state having a slope change point that is parallel to the left and right and deeper toward the middle in the axial direction. On the other hand, the work counter 3 has a gradient change point located deeper than the main shafts 1 and 2 at the axially intermediate position of the main shafts 1 and 2, and the pit is inclined to be deeper. It is built in the shape of a letter, and vertical wells 4, 5 are built in the ground position. And the leak of the up line system reaches the slope change point of the up line main pit 1 through the main pits f, j, the main mine g, h from both mine entrances, and flows from there to the working mine m toward one side. It reaches the bottom n of the vertical shaft, and is pumped up (pumped by a pump chamber) to the outlet of one vertical shaft 4 and discharged to one coast. On the other hand, the water leakage of the down line system reaches the gradient change point of the down line main mine 2 from the main shafts a, e, the main mine b, c from both mine entrances, and flows from there to the other working mine k. The water reaches the bottom 1 of the vertical shaft, and is pumped up (pumped by a pump chamber) to the outlet of the other vertical shaft 5 and discharged to the other coast.
[0009]
Now, in the submarine tunnel, the water leakage flow rate and the sodium ion concentration were measured at each of the measurement positions a to n, but there is no abnormality at each of the measurement positions f to j as a representative ( After confirming that the stability is secured), the flow rate of the leaked water (m ³ day ^-1 : cubic meters day minus the first power) over multiple years (for example, about 5 years) And measuring the sodium ion concentration (μg mL ⁻¹ : microgram milliliter to the power of −1) in the leaked water (ordinarily known measurement techniques can be adopted, such as ion selection) 2 to 6 show plots of these measured data. Observing these plotted graphs, although there is an inherent difference at the measurement position, the measured sodium ion concentration (marked with ○) and the leakage flow rate (marked with Δ) are seasonal with a roughly constant relationship at each measurement position. It was confirmed that the seawater leakage flow rate was constant, and that the inference that there was a change in the groundwater flow rate was correct. When each data is used as basic data at each measurement-corresponding observation position, and the sodium ion concentration deviating from this data is measured, the stability of the submarine tunnel has deteriorated and the stability has decreased. judge. As an example, at the measurement position i, the sodium ion concentration (marked with ●) measured in July of a certain year is the basis of the corresponding month even though there is almost no change in the leaked water flow (marked with ▲). From the data, it was observed that the seawater flow rate increased, and it was determined that the seawater flow rate increased due to the accelerated deterioration of the submarine tunnel structure. In order to investigate the authenticity of this judgment result, a detailed inspection was performed on the site, and in fact, it was confirmed that the deterioration of the tunnel structure progressed and the stability was impaired, and the reliability of the present invention was high. confirmed.
[0010]
On the other hand, at the measurement position j, it was observed that the sodium ion concentration (● mark) and the water leakage flow rate (▲ mark) measured in October of a certain year deviate from the basic data. In August of this year, drought was particularly low, resulting in a decrease in groundwater flow. As a result, the leakage flow decreased, but the incoming seawater flow did not change, so the concentration of sodium ions increased. Judged as an abnormal value. In order to investigate the authenticity of this judgment result, a detailed inspection was carried out at the site, and in fact, it was confirmed that the tunnel structure was not deteriorated and remained highly stable. By doing so, it was confirmed that the reliability of the present invention was increased.
[0011]
Next, FIG. 7 shows a stability determination device. The determination device 6 inputs the data of the sodium ion concentration, which is the seawater component, and the leakage flow rate to determine the stability of the underground structure. However, this includes a microcomputer having a rewritable storage unit as the control unit 7. Basic data of the water leakage flow rate and the sodium ion concentration at each of the measurement positions a to n is input to the storage unit. Furthermore, the control unit 7 includes an input operation tool 8 for inputting the measurement positions a to n, various data, and a measurement date, and a sensor for measuring sodium ion concentration (for example, an ion selective electrode). 9) is connected to the input interface side. When the measurement positions of a to n are selected and input, the measurement date is input, and further, the measured value of the sodium ion concentration of the water leakage measured by the sensor 9 is input, the control unit 7 stores these input results in advance. The basic data is compared and determined, and if it is determined that the sodium ion concentration deviates from the basic data, the fact that the stability is low is displayed on the display unit 10.
[0012]
By the way, although it is a criterion for stability, for example, measured values on the same day for multiple years (due to the nature of water leakage, there is no significant change in measured values on a daily basis. Of course, the average value may be obtained as a population, and normality / abnormality may be determined based on a deviation from the average value.
[Brief description of the drawings]
1A is a schematic longitudinal sectional view of a submarine tunnel, and FIG. 1B is a schematic transverse sectional view thereof.
FIG. 2 is a graph plotting a water leakage flow rate at a measurement position f and a sodium ion concentration in the water leakage.
FIG. 3 is a graph plotting a water leakage flow rate at a measurement position g and a sodium ion concentration in the water leakage.
FIG. 4 is a graph plotting a water leakage flow rate at a measurement position h and a sodium ion concentration in the water leakage.
FIG. 5 is a graph plotting a water leakage flow rate at a measurement position i and a sodium ion concentration in the water leakage.
FIG. 6 is a graph plotting a water leakage flow rate at a measurement position j and a sodium ion concentration in the water leakage.
FIG. 7 is a block circuit diagram of a stability determination device for an underground structure.
[Explanation of symbols]
1, 2 Main tunnel of submarine tunnel 3 Working tunnel 4 of submarine tunnel 5, 5 Vertical shaft 6 Measuring device 7 Control unit 8 Input operation tool 9 Sensor 10 Display unit

Claims (6)

  In determining the stability of underground structures that contain seawater containing seawater in the groundwater, the normal concentration of seawater components in the leaked water is measured and this change state is obtained in advance as basic data. A method for determining the stability of an underground structure, wherein when the concentration of a deviating seawater component is measured, it is determined that the stability of the underground structure has decreased.   When determining the stability of underground structures with seawater leaks that include seawater in the groundwater, the data storage means for storing the measured values of the normal concentration of seawater components in the leaked water as basic data, measure the concentration of seawater components Stability determination for determining that the stability of the underground structure has been reduced when the concentration of the seawater component measured by the concentration measuring means deviates from the stored basic data. An apparatus for determining the stability of an underground structure characterized by comprising means. According to claim 2, basic data, stability determine the constant device underground construction, which is a measured data throughout the year. According to claim 2 or 3, the concentration seawater components to be measured, the stability of determine the constant device underground construction, which is a sodium ion. In claim 2 , 3 or 4, when measuring basic data, the flow rate of water leakage is also measured, and when it is determined that the measured water leakage flow rate deviates from the normal water leakage flow rate. the stability determine the constant device underground construction being characterized in that so as not used for basic data the density measurement value at that time measured seawater components. In claim 2 , 3, 4 or 5, when determining the stability of the underground structure, the flow rate of the leakage water is also measured, and the measured leakage flow rate deviates from the normal leakage flow rate. In that case, the measured value of the concentration of the seawater component measured at that time is not used as the measured value for judging the stability of the underground structure. stability Han constant device.

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