KR20220095340A - Evaluation method and system of ground subsidence according to changes in groundwater level - Google Patents

Abstract

Disclosed are a method for evaluating the amount of ground subsidence according to changes in a groundwater level and a system therefor, which can evaluate the amount of ground subsidence according to changes in the groundwater level through numerical analysis (or numerical analysis model) during underground excavation of the center of a city and, by using the evaluation, can design water permeability of a cutoff wall. The method for evaluating the amount of ground subsidence according to changes in a groundwater level includes: a step of calculating changes in the groundwater level by numerically analyzing wide groundwater based on design information including water permeability information of a retaining wall and an on-site material of the wide groundwater; a step of calculating the amount of ground subsidence by analyzing ground stability based on a result of numerical analysis on the wide groundwater; a step of comparing the calculated amount of ground subsidence and the acceptable amount of ground subsidence for evaluating the amount of ground subsidence; a step of evaluating acceptable changes in the groundwater level according to the acceptable amount of ground subsidence when the calculated amount of ground subsidence is smaller than the acceptable amount of ground subsidence; and a step of calculating acceptable water permeability of the retaining wall according to the evaluated acceptable changes in the groundwater level.

Description

Evaluation method and system of ground subsidence according to changes in groundwater level

The present invention relates to a method and system for estimating ground settlement according to groundwater level fluctuations, and more particularly, evaluating the ground settlement amount based on the groundwater level fluctuations during underground excavation in urban areas through numerical analysis (or numerical analysis model) and utilizing the same It relates to a method and system for evaluating the amount of ground subsidence according to groundwater level fluctuations that can design the permeability of a water barrier wall.

In general, for the construction of structures such as pier foundations, underground driveways, buffer storage facilities, apartments, and buildings, and for the construction of various underground structures such as large-diameter water pipelines, city gas and sewage pipelines, the ground required for the construction of structures must be determined. By excavating in depth, the foundation excavation work, which becomes the foundation for the construction of the structure, will be carried out.

However, when the depth of excavation exceeds a certain depth in such foundation excavation work, the safety of workers and surrounding facilities may be harmed due to the collapse of soil and the like. In particular, when infiltrating water, such as groundwater, enters or leaches through the excavated ground, such as soft ground or sandy soil, the work environment becomes wet when excavating the foundation, impairing the mobility of workers and heavy equipment in use, thereby worsening work efficiency and work environment. This will adversely affect the strength and safety of the temporary retaining structure and the structure to be constructed.

To prevent this problem, the existing temporary retaining method prevents the collapse of the excavated surface due to water pressure and earth pressure by pre-constructing the barrier wall with grouting material vertically on the back circumference of the temporary retaining wall to be excavated before the foundation excavation work. The method of excavating the foundation was used after blocking the infiltration of water such as groundwater into the excavation of the foundation.

These existing temporary temporary facility construction methods have traditionally been focused on wall rigidity and degree of the sidewall, and the technology for leveling and improvement of the lower floor has not been developed much.

Therefore, in order to overcome this problem in the existing construction method, the temporary retaining wall is excessively constructed up to the deep bedrock layer to respond to water blocking, conduction and heaving.

However, this construction method is the main cause of the increase in the construction cost by excessively constructing the bottom of the temporary retaining wall to the bottom of the bedrock.

Meanwhile, due to the recent urban concentration, the scale and depth of excavation in the construction of facilities such as buildings are gradually increasing, and the effect of groundwater level fluctuations is intensifying due to the trend of enlargement of underground structures. is urgently needed.

In particular, as the unconsolidated soil (or soil) repeatedly undergoes a saturated-unsaturated state due to heavy rain or ground excavation, a change in the volume water content distributed in the pores of the soil occurs. It is necessary to develop a technology to predict ground subsidence based on the prediction of porosity.

In addition, in order to comprehensively predict the effects of groundwater fluctuations and the resulting ground deformation during excavation, the groundwater behavior prediction in saturated/unsaturated ground should be preceded. There is a need to develop modeling technology that can quantitatively predict

Accordingly, the technical task of the present invention is based on this point, and the object of the present invention is to evaluate the possibility of ground subsidence by numerical analysis of groundwater fluctuations and ground subsidence during urban ground excavation, to suggest the possibility of ground subsidence, and to be less than the allowable ground subsidence. In this case, it is to provide a method for evaluating the amount of ground subsidence according to groundwater level fluctuations that can be reflected in the design of the retaining wall by adjusting the permeability of the retaining wall.

Another object of the present invention is to provide a system for evaluating ground settlement according to ground water level fluctuations for performing the method for evaluating ground settlement according to ground water level fluctuations described above.

In order to realize the object of the present invention, the method for evaluating the amount of ground settlement according to the fluctuation of the groundwater level according to an embodiment is based on the design data including the permeability information of the retaining wall and the field data of the wide area groundwater, the amount of groundwater level change calculating, by a calculation unit, the amount of groundwater level change by numerical analysis of the wide area groundwater; calculating the amount of ground settlement by analyzing the stability of the ground by the ground settlement calculation unit based on the results of the wide-area groundwater numerical analysis; comparing the calculated amount of ground settlement with the allowable amount of ground settlement by a comparator to evaluate the amount of ground settlement; if it is checked that the calculated amount of ground settlement is smaller than the allowable amount of ground settlement, evaluating, by an evaluation unit, the amount of change in the allowable groundwater level according to the allowable amount of settlement; and calculating the allowable permeability of the retaining wall according to the evaluated allowable groundwater level change by the water permeability calculation unit, wherein the ground settlement amount (Ssub) is the sum of the compression rates in each soil layer or the specific storage coefficient (Ss) is calculated from

According to the method and system for evaluating the amount of ground settlement according to the groundwater level fluctuation, it is possible to evaluate the ground settlement amount based on the groundwater level change during underground excavation through numerical analysis, and by using this, it is possible to design the water permeability of the water barrier. .

1 is a block diagram schematically illustrating a system for evaluating ground settlement according to groundwater level fluctuations according to an embodiment of the present invention.
2 is a flowchart schematically illustrating a method for evaluating ground settlement according to groundwater level fluctuations according to an embodiment of the present invention.
3a is a water level drop curve versus permeability for groundwater fluctuation analysis, FIG. 3b is a water level drop versus ground settlement curve for ground settlement analysis according to groundwater level fluctuations, and FIG. 3c is an allowable water level change analysis according to allowable ground settlement amount is a water level drop versus ground subsidence curve for water level drop, and FIG. 3D is a water permeability versus water level drop curve for allowable permeability analysis according to the allowable water level change.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. Since the present invention can make various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, It should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It should be construed as not precluding the possibility of the presence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

1 is a block diagram for evaluating the amount of ground settlement according to groundwater level fluctuations according to an embodiment of the present invention.

Referring to FIG. 1 , the ground settlement evaluation system 100 according to the groundwater level fluctuation according to an embodiment of the present invention includes a design data DB 10 , a field data DB 20 , a groundwater level change calculation unit 110 , It includes a ground subsidence calculation unit 120 , a comparison unit 130 , a message output unit 140 , an allowable groundwater level evaluation unit 150 , and a permeability calculation unit 160 . In this embodiment, the ground settling amount evaluation system 100 according to the groundwater level fluctuation is a design data DB 10, a field data DB 20, a groundwater level change calculation unit 110, a ground settlement amount calculation unit 120, a comparison It has been described that it includes the unit 130, the message output unit 140, the allowable groundwater level evaluation unit 150, and the permeability calculation unit 160, but this is only logically divided for convenience of explanation and is divided into hardware didn't do it

The groundwater level change calculation unit 110 numerically calculates the wide-area groundwater based on the design data including the retaining wall permeability information stored in the design data DB 10 and the field data of the wide-area groundwater stored in the field data DB 20 . Analyze and calculate the amount of groundwater level change.

The ground settlement amount calculation unit 120 calculates the ground settlement amount by analyzing the ground safety based on the result of numerical analysis of the wide area groundwater.

Referring back to FIG. 1 , the comparison unit 130 compares the ground settlement amount calculated by the ground settlement amount calculating unit 120 and the allowable ground settlement amount in order to evaluate the ground settlement amount. The allowable ground settlement amount may be stored in a separate allowable ground settlement amount DB 30 .

When it is checked that the calculated amount of ground settlement is equal to or greater than the allowable amount of ground settlement, the message output unit 140 outputs a message requesting establishment of a settlement prevention measure.

The allowable groundwater level evaluation unit 150 evaluates the amount of change in the groundwater level when it is checked that the calculated amount of ground settlement is smaller than the allowable amount of ground settlement.

The permeability calculation unit 160 calculates the permeability of the retaining wall when the groundwater level change evaluated by the allowable groundwater level evaluation unit 150 is the allowable groundwater level change amount. The retaining method for constructing a retaining wall with the calculated water permeability can be divided into the CIP method, the H-PILE + earth plate method, the slurry wall method, and the SCW (Soil Cement Wall) method.

The CIP method is a method of forming a continuous column wall by perforating the ground with a radius of curvature of 400 mm to 1,500 mm and then injecting reinforcing bars or H-beams and concrete. The CIP method can be constructed reasonably and economically, and is vibration-free and noise-free. It is widely used in terms of construction.

The H-PILE + earth plate construction method is a universal construction method using a driving machine. In other words, H-PILE + earth plate is used, and a wale is installed for stress transmission. The H-PILE + earth plate method is the most widely used and has abundant experience and technology accumulation. In addition, it requires a separate waterproofing work, and when the concrete work is completed, it is dismantled and reused, so the cost reduction effect is great.

The slurry wall method is a method of excavating a trench and continuously constructing an underground wall with a panel inserted with a reinforcing bar mesh. The slurry wall method is often adopted when there are many complaints in the downtown area. It has perfect water-repellent performance and is used as a building basement wall.

The SCW method is drilled using a special multi-axis mechanism. It is constructed by injecting cement paste and Bentonite solution. H-beam is inserted into the ball to act as a water barrier and earth wall. The SCW method has very little effect on the surrounding ground. In addition, it has high water-resistance performance, low noise and vibration, shortened construction period, and many construction achievements.

In general, ground stability evaluation was performed by analyzing groundwater level fluctuations according to permeability, and then analyzing the amount of ground settlement according to the groundwater level fluctuations.

However, according to the present invention, in addition to the process of analyzing the ground settlement amount after analyzing the groundwater level fluctuations described above, the allowable water level change according to the allowable ground settlement amount is analyzed, and then the allowable permeability according to the allowable water level change amount is analyzed. Accordingly, if the amount of ground settlement is within the allowable ground settlement amount, the water level drop corresponding to the allowable ground settlement amount can be selected and used to design a retaining wall with controlled permeability.

Through this, it is possible to reduce the overdesign for the complete waterproofing of the retaining wall in the area where groundwater is abundant in the downtown area. In addition, it is possible to design a retaining wall at a low cost while being easier to construct compared to the conventional complete waterproofing method.

2 is a flowchart schematically illustrating a method for evaluating ground settlement according to groundwater level fluctuations according to an embodiment of the present invention. 3a is a water level drop curve versus permeability for groundwater fluctuation analysis, FIG. 3b is a water level drop versus ground settlement curve for ground settlement analysis according to groundwater level fluctuations, and FIG. 3c is an allowable water level change analysis according to the allowable ground settlement amount It is a water level drop versus ground subsidence curve for this purpose, and FIG. 3D is a water level drop versus water permeability curve for permeability analysis according to the allowable water level change.

Referring to FIG. 2 , design data including permeability information of the retaining wall and field data of wide-area groundwater are input (step S110). The design data and the field data are the data stored in the design data DB (10, shown in FIG. 1) and the field data DB (20, shown in FIG. 1), respectively, in the groundwater level change calculation unit (110, in FIG. 1). shown) can be performed in such a way that the input is received.

Based on the design data and the field data input in step S110, the amount of groundwater level change is calculated by numerically analyzing the wide-area groundwater (step S120). For example, as shown in FIG. 3A , a groundwater level change amount (Drawdown) may be calculated in response to permeability information (Permeability) in a specific area. In FIG. 3A , the amount of change in the groundwater level is expressed as a curve in response to permeability, but this is expressed as a curve for convenience of explanation and will be expressed in a manner in which one point is mapped for one area. The calculation of the groundwater level change amount may be calculated by the groundwater level change amount calculating unit 11 shown in FIG. 1 .

Based on the result calculated in step S120, the ground safety is analyzed to calculate the amount of ground settlement (step S130). For example, as shown in FIG. 3B , a land subsidence may be calculated in response to a groundwater level drawdown. In FIG. 3B, the amount of ground subsidence is also expressed as a curve in response to the change in the groundwater level, but this is expressed as a curve for convenience of explanation and will also be expressed in a manner in which one point is mapped for one area. The ground The calculation of the settlement amount may be performed by the ground settlement amount calculation unit 120 shown in FIG. 1 .

In this embodiment, it has been described that the groundwater level change amount is calculated after calculating the groundwater level change amount, but the step of calculating the groundwater level change amount and the ground settlement amount calculation step can be performed at the same time.

In order to evaluate the amount of ground settlement, the calculated amount of ground settlement and the allowable amount of ground settlement are compared (step S140). The comparison of the calculated amount of ground settlement and the allowable amount of ground settlement may be performed by the comparison unit 130 shown in FIG. 1 .

When it is checked that the calculated ground settlement amount is greater than or equal to the allowable ground settlement amount in step S140, a settlement prevention measure establishment message is output (step S150). may be performed by the unit 140 .

If it is checked that the calculated amount of ground settlement is smaller than the allowable amount of ground settlement in step S140, as shown in FIG. 3c, the allowable groundwater level change according to the allowable amount of settlement is calculated (step S160). The calculation of the allowable groundwater level change amount may be performed by the allowable groundwater level evaluation unit 150 shown in FIG. 1 .

If the evaluated allowable groundwater level change amount is the allowable groundwater level change amount, as shown in FIG. 3D , the allowable permeability of the retaining wall is calculated (step S170). The calculation of the allowable water permeability may be performed by the water permeability calculation unit 160 illustrated in FIG. 1 .

Based on the calculated allowable permeability of the earthen wall, the wall permeability is proposed at the time of design (step S180).

As described above, to evaluate the ground stability, if the calculated amount of ground settlement is checked to be smaller than the allowable ground settlement amount, the allowable groundwater level change according to the allowable settlement amount is additionally calculated, and the allowable permeability of the retaining wall is additionally calculated do.

According to the present invention, it is possible to evaluate the amount of ground subsidence according to groundwater fluctuations through numerical analysis. Typically, retaining walls are of full order with zero permeability.

If the amount of ground settlement is within the allowable amount of ground settlement (for example, 25mm), the water level drop corresponding to the allowable amount of ground settlement can be selected and suggested to adjust the permeability of the retaining wall using this.

Through this, it is possible to reduce the overdesign for complete waterproofing of the retaining wall in the downtown area where groundwater is abundant (that is, the groundwater level is close to the ground surface and the permeability is good). Here, the depth from the surface to the groundwater level is obtained by subtracting the groundwater level from the surface elevation.

Through this, the present invention can design a retaining wall at a low cost and easy to construct compared to a conventional complete waterproofing method.

As described above, according to the present invention, it is possible to evaluate the amount of ground subsidence based on the fluctuation of the groundwater level during urban ground excavation through numerical analysis, and use this to design the water permeability of the order wall.

Although the above has been described with reference to the embodiments, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand.

Claims (2)

Calculating the amount of groundwater level change by numerically interpreting the sub-regional groundwater calculation based on the design data including the permeability information of the retaining wall and the field data of the wide area groundwater;
estimating the amount of ground settlement by analyzing the stability of the ground by the ground settlement amount calculation unit based on the result of the numerical analysis of the wide area groundwater; comparing the calculated amount of ground settlement with the allowable amount of ground settlement by a comparator to evaluate the amount of ground settlement;
if it is checked that the calculated ground settlement amount is smaller than the allowable ground settlement amount, evaluating, by an evaluation unit, the allowable groundwater level change amount according to the allowable settlement amount; and
Comprising the step of calculating the allowable water permeability of the retaining wall according to the estimated allowable groundwater level change by the water permeability calculation unit,
The ground settlement amount (Ssub) is a method for evaluating ground settlement amount according to groundwater level fluctuations, which is calculated by summing the compressibility in each soil layer or from a non-retention coefficient (Ss). The groundwater level fluctuation according to claim 1, further comprising outputting a message requesting establishment of a settlement prevention measure by a message output unit when it is checked that the calculated amount of ground settlement is equal to or greater than the allowable amount of ground settlement. ground settlement evaluation method according to

Images