JP4541449B1 - Ground improvement method - Google Patents

Abstract

[PROBLEMS] To provide a ground improvement method capable of reducing the construction period and construction cost while obtaining the embedding effect even when there is no bedrock up to the embedding depth level at which the embedding effect can be obtained at the construction site of the nuclear related building. To provide.
SOLUTION: The ground improvement method is a ground improvement method in the case where there is no bedrock 2 up to the embedding depth level at which the embedding effect is obtained in the construction site of the nuclear related building 5, and the surrounding area of the underground portion in the nuclear related building 5 Then, the artificial rock mass is placed in the ground improvement range 1 that spreads on the horizontal plane specified based on the width D of the underground portion.
[Selection] Figure 1

Description

  The present invention relates to a ground improvement method. In particular, the present invention relates to a ground improvement method for placing artificial rock in the construction of nuclear related buildings.

  Conventionally, it is necessary to construct a nuclear-related building on a bedrock that has sufficient supporting performance against the weight of the nuclear-related building and an assumed earthquake load.

  Moreover, by embedding a part of the building in the rock having predetermined physical properties, the embedding effect can be obtained as an effect of restraining the side surface of the building and reducing the load caused by the earthquake.

Therefore, in order to embed the underground part of the building in the bedrock, as a space for constructing the underground part, excavate the bedrock in a range wider than the area of the underground part, and after the building construction, the bedrock between the building and the bedrock There has been proposed a building installation method in which an artificial bedrock (for example, manmade rock) having equivalent physical properties is placed (Patent Document 1).
According to such a building installation method, in the building design, not only the reaction force from the bedrock at the bottom of the building but also the reaction force from the bedrock and the artificial bedrock at the side of the building can be used, so that the building stability can be ensured.

JP-A-8-86117

  However, the building installation method of Patent Document 1 cannot be applied when there is no bedrock up to the embedding depth level at which the embedding effect can be obtained at the planned construction site of the building.

In such a case, the ground improvement range, which is a planar range in which the artificial rock is provided, is unknown.
According to the nuclear power plant seismic design technical guideline (JEAG4601), “The reference plane for the calculation of seismic force should be a ground surface with a horizontal spread as a rule. “The seismic force will be evaluated based on the seismic intensity of the underground part below the surface.”, “However, in the actual site, when multiple buildings and structures are built in close proximity, There are cases where there are slopes, etc., and the buildings / structures are not necessarily embedded alone on the horizontal ground surface. 75% or more) is in contact with the ground, and the ground has a flat area more than that of the building / structure, this is used as the reference plane. "

  In other words, the nuclear power plant seismic design technical guideline (JEAG4601) has a description that it can be interpreted that a plane spread of about the width of the building is necessary in setting the reference plane for calculating the seismic force, but the embedding effect can be obtained. The ground improvement range is not described.

On the other hand, assuming that the ground improvement range where the embedding effect can be obtained is unknown, if a ground improvement method that can be assumed that the ground improvement range has expanded semi-infinitely, the ground improvement range becomes unnecessarily wide, will be ground improvement in dynamic soil properties performance high artificial bedrock (1 m ³ per cement weight is large artificial rock), the ground improvement work, construction period for a long time, so that the large construction costs take .

  In the case where there is no rock up to the embedding depth level at which the embedding effect can be obtained at the planned construction site of the building, the inventors perform analytical verification of the ground improvement range when the embedding effect is obtained, and the embedding effect is obtained. The ground improvement range, which is a flat area where the artificial rock mass is installed, was identified.

  The present invention is a ground improvement method capable of suppressing the construction period and construction cost while obtaining the embedding effect even when there is no rock to the embedding depth level at which the embedding effect is obtained at the construction site of the nuclear related building. The purpose is to provide.

  In order to achieve the above object, the present invention provides the following ground improvement method.

(1) Oite the construction site of the nuclear architecture, ground rock with supporting performance for the nuclear buildings, if not reached the reference surface, underground portion in the nuclear building a surrounding, Oite the ground improvement range extending to the specified horizontal plane on the basis of the width of the underground part, by drilling the Umado covering the surface of the rock to expose the surface of the rock, said from the surface of the rock A ground improvement method for placing artificial rock to a reference surface , wherein the width of the ground improvement range in a predetermined direction on a horizontal plane is substantially the same as the width of the underground portion in the predetermined direction Improved construction method.

  According to the invention of (1), even if the rock mass is not at the embedding depth level at which the embedding effect can be obtained, the artificial rock mass is placed in the ground improvement range that spreads in the horizontal plane around the underground part in the nuclear related building. Therefore, the embedding effect can be obtained. Here, the nuclear-related building in the present invention includes a building in a nuclear-related facility in addition to a reactor building.

  By the way, in the ground improvement method, excavated soil that exists in the ground improvement range, cement is mixed into a part of the excavated soil, or from the outside, and the artificial rock is generated. Place artificial rock in the ground improvement area. The excavated soil that was not used for the artificial bedrock will be discarded. That is, as the ground improvement range becomes wider, the excavation range and the range where artificial rock is placed are increased, and therefore the construction period required for the ground improvement becomes longer. In addition, the wider the ground improvement range, the greater the amount of cement and waste to be excavated, such as excavated soil and carry-in soil, so the construction cost for ground improvement also increases.

  Therefore, because the ground improvement range was specified based on the width of the underground part of the nuclear-related building, the artificial rock bed placement range was unnecessarily widened to assume that the artificial bedrock had spread infinitely. Therefore, it is not necessary to unnecessarily increase the performance of the dynamic ground physical properties of the artificial rock, and the construction period in the ground improvement work can be shortened. Moreover, since the amount of cement to be mixed and landfill to be discarded, such as carry-in soil, can be reduced, construction costs can be reduced.

  Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the construction site of the nuclear related building, we provide a ground improvement method that can reduce the construction period and construction cost while obtaining the embedding effect it can.

Moreover, according to invention of (1), the width | variety of the ground improvement range of the predetermined direction in a horizontal surface was made substantially the same as the width | variety of the underground part in the said predetermined direction. Thereby, for example, in the portion where the width of the underground portion is narrow, the width of the ground improvement range can also be narrowed, so that the placement range of the artificial rock can be further limited.
  Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the construction site of the nuclear related building, a ground improvement method that can further reduce the construction period and construction cost while obtaining the embedding effect. Can be provided.

(2) In the ground improvement range, a first artificial rock having a predetermined shear wave velocity is placed, and a first range in contact with the nuclear-related building has a shear wave velocity lower than the predetermined shear wave velocity. the second artificial rock is pouring, ground improvement method according to claim 1, characterized in Rukoto to have a second range adjacent to the outside of the first range.

(3) In the planned construction site of a nuclear related building, if the ground surface of the rock that has supporting performance for the nuclear related building does not reach the reference plane, In the ground improvement range that spreads in the horizontal plane specified based on the width of the underground part, excavating the soil covering the ground surface of the rock to expose the ground surface of the rock, from the ground surface of the rock to the reference plane, A ground improvement method for placing an artificial rock, wherein the ground improvement range includes a first range in which a first artificial rock having a predetermined shear wave velocity is placed and is in contact with the nuclear related building, and the predetermined range. second artificial rock having a lower shear wave velocity shear wave velocity is pouring, the earth plate improved method you; and a second range adjacent to the outside of the first range.

According to the invention of (2) or (3), the ground improvement range is divided into a first range in contact with the nuclear related building and a second range in contact with the outside of the first range. A second artificial rock mass having a shear wave velocity lower than that of the first artificial rock mass to be cast in one range is cast.
Thereby, for example, the amount of cement per 1 m ³ of the second artificial rock in the second range can be made smaller than the amount of cement per 1 m ³ of the first artificial rock in the first range. Construction costs can be reduced.
Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the construction site of the nuclear related building, a ground improvement method that can further reduce the construction period and construction cost while obtaining the embedding effect. Can be provided.

  (4) The width of the first range in a predetermined direction on the horizontal plane and the width of the second range in the predetermined direction are each smaller than the width of the underground portion in the predetermined direction. Ground improvement method.

According to invention of (4), the width | variety of the 1st range of the predetermined direction in a horizontal surface and the width | variety of the 2nd range of the said predetermined direction were made narrower than the width | variety of the underground part in the said predetermined direction.
Thereby, the construction cost of the ground improvement work can be further suppressed by suppressing the width of the first range of the first artificial rock mass and the width of the second range of the second artificial rock mass to a width narrower than the width of the underground portion.
Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the construction site of the nuclear related building, a ground improvement method that can further reduce the construction period and construction cost while obtaining the embedding effect. Can be provided.

  According to the present invention, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building, the ground can be obtained while the embedding effect is obtained and the construction period and construction cost can be suppressed. An improved construction method can be provided.

FIG. 1 is an explanatory diagram of a ground improvement method according to an embodiment of the present invention. It is a figure which shows the model which assumed the width | variety of the ground improvement range in the dynamic analysis 1. It is a figure which shows the model which made the width | variety of the ground improvement range in the dynamic analysis 1 substantially 0.5 times the width | variety of the underground part of a reactor building. It is a figure which shows the model which made the width | variety of the ground improvement range in dynamic analysis 1 substantially the same as the width | variety of the underground part of a reactor building. It is a figure which shows the model which made the width | variety of the ground improvement range in the dynamic analysis 1 substantially 3 times the width | variety of the underground part of a nuclear reactor building. It is a figure which shows the model which made the width | variety of the ground improvement range in the dynamic analysis 1 substantially 5 times the width | variety of the underground part of a nuclear reactor building. It is a figure which shows the model which set the 1st artificial rock which has a predetermined shear wave velocity in the whole ground improvement range in the dynamic analysis 2. FIG. It is a figure which shows the model which set the 2nd artificial rock in which the shear wave velocity is lower than the 1st artificial rock in the whole ground improvement range in the dynamic analysis 2. It is a figure which shows the model which set the 1st artificial rock mass and the 2nd artificial rock mass in half in the ground improvement range in the dynamic analysis 2.

[Embodiment]
Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.

FIG. 1 is an explanatory diagram of a ground improvement method according to an embodiment of the present invention.
With reference to FIG. 1, the ground improvement construction method which concerns on this embodiment is demonstrated.
The ground improvement method according to the present embodiment is applied when the bedrock 2 does not exist up to the embedding depth level at which the embedding effect is obtained in the planned construction site of the nuclear related building 5.
In the present embodiment, the embedding depth level at which the embedding effect is obtained is the level of the reference plane 3 of the nuclear related building 5. In other words, when there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building 5, sufficient support performance against the weight of the nuclear related building 5 and the load due to the assumed earthquake. This is a case where the ground surface of the rock mass 2 having the height does not reach the level of the reference plane 3. In the present embodiment, the buried soil 50 covering the ground surface of the rock mass 2 is accumulated from the ground surface of the rock mass 2 to the level of the reference plane 3, but the buried soil 50 has almost no support performance.

  In the ground improvement method according to the present embodiment, first, the ground 50 covering the ground surface of the rock mass 2 is excavated in the planar range of the ground improvement range 1 extending in the horizontal plane around the underground portion of the nuclear related building 5. 2 is exposed. Next, after constructing an underground portion of the nuclear-related building 5 using the exposed rock mass 2 as a support layer, cement is mixed into a part of the excavated buried soil 50 to generate the first artificial rock masses 100 and 110. In the ground improvement range 1, the first artificial rocks 100 and 110 are placed up to the reference plane 3.

  The ground improvement range 1 includes a first range 10 that contacts the outside of the underground portion of the nuclear power related building 5 and a second range 11 that contacts the outside of the first range 10.

In the first range 10, the width in the predetermined direction on the horizontal plane is substantially half (0.5D) of the width D of the underground portion of the nuclear related building 5 in the predetermined direction. The first artificial rock 100 is placed in the first range 10.
The first artificial rock mass 100 is a manmade rock, and is generated so as to have a predetermined shear wave velocity by mixing a predetermined amount of cement per 1 m ^{3 in} the buried soil 50.

In the second range 11, the width in the predetermined direction on the horizontal plane is approximately half (0.5D) of the width D of the underground portion of the nuclear related building 5 in the predetermined direction. In the second range 11, a second artificial rock 110 is placed.
The second artificial rock 110 is a manmade rock, and the amount of cement per 1 m ³ mixed in the buried soil 50 is made smaller than the predetermined amount of cement mixed in the first artificial rock 100, and the first artificial rock in the first range 10 is used. It is generated so that the shear wave velocity is lower than that of the rock mass 100.

[Dynamic analysis of ground improvement range 1]
<Analysis outline>
2-6 is a figure which shows the model in the dynamic analysis 1 of the ground improvement range.
The purpose of the dynamic analysis 1 is to grasp the tendency of the response value depending on the width of the ground improvement range, with respect to a predetermined direction cross section of the nuclear-related building 5 to be constructed (see FIG. 1).
In the dynamic analysis 1, specified earthquake motion is input to the ground-building coupled 2D FEM model, and the nuclear-related building 5 is modeled as a reactor building consisting of 8 layers built on the foundation. A pullback analysis was performed on the furnace building (hereinafter referred to as R / B) 15.

<Analysis conditions>
In the dynamic analysis 1, R / B 15 is a dynamic mass point spring mass multi-axis model, and rigid beam elements are arranged on the embedded side wall portion and the foundation bottom surface portion. This beam element was pin-coupled at each floor level, and the spring mass model was connected to each floor with a rigid horizontal spring. Each floor was assumed to be a rigid floor. In FIG. 2 to FIG. 6, a dynamic mass point spring mass multi-axis model is described as R / B 15 for easy understanding.

The ground was a water Heisei layer ground, the base depth of the R / B 15 was a uniform bedrock 2, and the embedded lateral portion of the R / B 15 was modeled as the first artificial rock 100 and the buried soil 50.
The dynamic physical properties (shear wave velocity) of each base were based on the dynamic physical properties of the rock mass 2 having sufficient support performance for the reactor building to be constructed. The dynamic physical properties of the first artificial rock 100 were set to approximately 75% of the dynamic physical properties of the rock 2. The dynamic properties of the buried soil 50 were set to about 10% of the dynamic properties of the bedrock 2.

  In dynamic analysis 1, the width of the appropriate ground improvement range was verified by comparing the response values in the five models with the width of the ground improvement range as a parameter. Here, the response value is a response value for every 9 layers in the R / B 15 with 8 layers added to the base. In addition, the width of the ground improvement range is specified based on the width D of the underground portion of the R / B 15 except when infinite. That is, if the width of the ground improvement range is 2.0D, it is twice the width D of the underground portion, and if it is 0.5D, it is 0.5 times the width D of the underground portion.

  The five models of the specific dynamic analysis 1 are the ground improvement range 1a model when the width of the ground improvement range is assumed to be infinite, and the ground improvement range 1b model when the width of the ground improvement range is 0.5D. And the ground improvement range 1c model when the width of the ground improvement range is 1.0D, the ground improvement range 1d model when the width of the ground improvement range is 3.0D, and the width of the ground improvement range 5. It is a ground improvement range 1e model in the case of 0D.

FIG. 2 is a diagram showing a ground improvement range 1a model in which the width of the ground improvement range is assumed to be infinite in the dynamic analysis 1. FIG.
FIG. 3 is a diagram illustrating a ground improvement range 1b model in which the width of the ground improvement range in the dynamic analysis 1 is approximately 0.5 times (0.5D) the width of the underground portion of the reactor building.
FIG. 4 is a diagram showing a ground improvement range 1c model in which the width of the ground improvement range in the dynamic analysis 1 is substantially the same as the width of the underground portion of the reactor building (1.0D).
FIG. 5 is a diagram showing a ground improvement range 1d model in which the width of the ground improvement range in the dynamic analysis 1 is approximately three times (3.0 D) the width of the underground portion of the reactor building.
FIG. 6 is a diagram showing a ground improvement range 1e model in which the width of the ground improvement range in the dynamic analysis 1 is approximately five times (5.0D) the width of the underground portion of the reactor building.

<Analysis results>
(Maximum acceleration distribution of the ground)
As for the maximum acceleration distribution of the ground, the acceleration of the buried 50 portion was large, but there was no significant difference in the acceleration distribution in the underground portion of the R / B 15 in the ground improvement ranges 1a to 1e.

(Maximum response acceleration distribution of R / B15)
Table 1 shows the ground improvement range 1b (0.5D) model to the ground improvement range 1e (5.0D) for the response value of each layer in the ground improvement range 1a (infinite assumption) model for the maximum response acceleration distribution of R / B15. It is a table | surface which shows the ratio of the response value of each hierarchy in a model. In Table 1, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00.

As shown in Table 1, the larger the width of the ground improvement range, the closer to the response value of the ground improvement range 1a (infinite assumption) model.
Moreover, when compared with the lower layer part of R / B15, the response value of the ground improvement range 1b (0.5D) model is approximately 10% higher than the response value of the ground improvement range 1a (infinite assumption) model. The response values of the range 1c (1.0D) model and 1d (3.0D) model approximated the response value of the ground improvement range 1a (infinite assumption) model.

(Maximum shear force distribution of R / B15)
Table 2 shows the ground improvement range 1b (0.5D) model to the ground improvement range 1e with respect to the response value of each layer in the ground improvement range 1a (infinite assumption) model with respect to the maximum layer shear force distribution of each axis of R / B15. It is a table | surface which shows the ratio of the response value of each hierarchy in a (5.0D) model. In Table 2, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00. Further, in Table 2, the ratio of the upper and lower response values in each hierarchy is shown in two stages.

  As shown in Table 2, the response value of the ground improvement range 1b (0.5D) model is approximately 10% higher than the response value of the ground improvement range 1a (infinite assumption) model, but the ground improvement range 1c (1. The response value of the (0D) model was relatively approximate to the response value of the ground improvement range 1a (infinite assumption) model.

(Maximum bending moment distribution of R / B15)
Table 3 shows ground improvement range 1b (0.5D) model to ground improvement range 1e for the response value of each layer in the ground improvement range 1a (infinite assumption) model for the maximum bending moment distribution of each axis of R / B15. 5.0D) It is a table | surface which shows the ratio of the response value of each hierarchy in a model. In Table 3, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00. In Table 3, the ratio of the response values at the upper and lower levels in each hierarchy is shown in two stages.

As shown in Table 3, the response value of the ground improvement range 1b (0.5D) model was approximately 10% higher than the response value of the ground improvement range 1a (infinite assumption) model.
The response value of the ground improvement range 1c (1.0D) model was relatively approximate to the response value of the ground improvement range 1a (infinite assumption) model.
The response values of the ground improvement range 1d (3.0D) model and 1e (5.0D) model were substantially the same as the response values of the ground improvement range 1a (infinite assumption) model.

<Verification>
The analysis result of the above dynamic analysis 1 is verified.
Each response value of the ground improvement range 1d (3.0D) model and 1e (5.0D) model can be regarded as equivalent to each response value of the ground improvement range 1a (infinite assumption) model.
Each response value of the ground improvement range 1c (1.0D) model was relatively approximate to each response value of the ground improvement range 1a (infinite assumption) model.
From the above results, it is understood that the embedding effect can be obtained with the ground improvement range 1c (1.0D) model in which the ground improvement range is the same width (1.0D) as the width D of the underground portion of R / B15. It was.

[Dynamic analysis of ground improvement range 2]
<Analysis outline>
7-9 is a figure which shows the model in the dynamic analysis 2 of a ground improvement range.
The dynamic analysis 2 is an analysis for additionally examining the dynamic analysis 1. In the following description of the dynamic analysis 2, the same components as those of the dynamic analysis 1 are denoted by the same reference numerals, and the description thereof is omitted or simplified. Also, the description of the same analysis conditions as those of the dynamic analysis 1 is omitted or simplified.
The dynamic analysis 2 is different from the dynamic analysis 1 in the ground type and parameters.
<Analysis conditions>
The ground is a water Heisei layer ground, the bedrock 2 below the foundation of R / B15 is a uniform bedrock, and the R / B15 embedding side part is the first artificial rock 100 and the buried soil 50, the second artificial rock 110 And three types of the first artificial rock masses 100 and 110 and the buried soil 50 were modeled.
The dynamic physical properties (shear wave velocity) of the second artificial rock mass 110 were set to about 50% to 45% of the dynamic physical properties of the first artificial rock mass 100.

In the dynamic analysis 2, the width of the ground improvement range was set to a width (1.0 D) that is approximately the same as the width D of the underground portion of R / B15.
In the dynamic analysis 2, the response values in three types of models using the dynamic physical properties (shear wave velocity) of the artificial rock in the width (1.0D) of the ground improvement range as parameters were compared.

  The three models of the specific dynamic analysis 2 are the ground improvement range 1f model (the ground improvement range 1c (1.0D) in the dynamic analysis 1) and the first artificial rock 100 set in the entire ground improvement range. Equivalent), a ground improvement range 1g model in which the second artificial rock 110 is set in the entire ground improvement range, and a ground improvement range 1h in which the first artificial rock 100 and the second artificial rock 110 are set in half in the ground improvement range. It is a model.

  In the dynamic analysis 2, the appropriateness of the ground improvement range 1h model was particularly verified by comparing the response values in the three types of models and the ground improvement range 1a (infinite assumption) model (see FIG. 2). Here, the response value is a response value for every 9 layers in the R / B 15 with 8 layers added to the base.

FIG. 7 is a diagram showing a ground improvement range if model in which the first artificial rock 100 is set in the entire ground improvement range in the dynamic analysis 2.
FIG. 8 is a diagram showing a ground improvement range 1 g model in which the second artificial rock 110 is set in the entire ground improvement range in the dynamic analysis 2.
FIG. 9 is a diagram showing a ground improvement range 1 h model in which the first artificial rock 100 and the second artificial rock 110 are set in half in the ground improvement range in the dynamic analysis 2.

<Analysis results>
(Maximum response acceleration distribution of R / B15)
Table 4 shows the ground improvement range 1a (first artificial rock) model to ground improvement range 1h (first artificial rock) for the response value of each layer in the ground improvement range 1a (infinite assumption) model for the maximum response acceleration distribution of R / B15. It is a table | surface which shows the ratio of the response value of each hierarchy in a (rock mass + 2nd artificial rock mass) model. In Table 4, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00.

  As shown in Table 4, in comparison with the ground improvement range 1a (infinite assumption) model for the maximum response acceleration distribution of R / B15, the ground improvement range 1h model was not clearly different from the ground improvement range 1f model. .

(Maximum shear force distribution of R / B15)
Table 5 shows the ground improvement range 1f (first artificial rock) model to the ground improvement range with respect to the response value of each layer in the ground improvement range 1a (infinite assumption) model for the maximum layer shear force distribution of each axis of R / B15. It is a table | surface which shows the ratio of the response value of each hierarchy in 1h (1st artificial rock mass + 2nd artificial rock mass) model. In Table 5, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00. In Table 5, the ratios of the upper and lower response values in each layer are shown in two stages.

As shown in Table 5, the ground improvement range 1h model was relatively consistent with the ground improvement range 1a (infinite assumption) model for the maximum layer shear force distribution of each axis of R / B15.
In addition, regarding the maximum shear force of the lower layer of R / B15, the ground improvement range 1h model is significantly lower than the ground improvement range 1g model, and it can be confirmed that the effect of ground improvement appears. It was.

(Maximum bending moment distribution of R / B15)
Table 6 shows the ground improvement range 1f (first artificial rock) model to ground improvement range 1h (first artificial rock) for the response value of each layer in the ground improvement range 1a (infinite assumption) model for the maximum bending moment distribution of R / B15. It is a table | surface which shows the ratio of the response value of each hierarchy in a (rock mass + 2nd artificial rock mass) model. In Table 6, the response value of each layer in the ground improvement range 1a (infinite assumption) model is set to 1.00. Further, in Table 6, the ratio of the upper and lower response values in each layer is shown in two stages.

  As shown in Table 6, with respect to the maximum bending moment distribution of each axis of R / B15, the ground improvement range 1h model was substantially consistent with the ground improvement range 1a (infinite assumption) model.

<Verification>
The analysis result of the above dynamic analysis 2 is verified.
Each response value of the ground improvement range 1h model was not clearly different from the ground improvement range 1f model in comparison with the ground improvement range 1a (infinite assumption) model.
From the above results, as the ground improvement range, the first artificial rock 100 and the second artificial rock 110 (the first artificial rock mass 110 (the first artificial rock mass 110) in the ground improvement range having the same width (1.0D) as the width D of the underground portion of the R / B 15). It has been found that the embedding effect can be obtained with a ground improvement range 1 h model in which the artificial rock mass having an approximately 50% to 45% dynamic physical property (shear wave velocity) of the artificial rock mass 100) is set in half in the ground improvement range.

According to the embodiment, the following effects are obtained.
Even if the rock mass 2 does not reach the embedding depth level (reference plane 3) at which the embedding effect can be obtained, the artificial rock masses 100, 110 are placed in the ground improvement range 1 extending in the horizontal plane around the underground portion of the nuclear related building 5. Since it is placed, an embedding effect can be obtained.

Further, from the analysis result of the dynamic analysis 1, the ground improvement range 1 was specified based on the width D of the underground portion of the nuclear related building 5. Therefore, since it is not necessary to unnecessarily widen the placement range of the artificial rock 100 or unnecessarily increase the dynamic ground physical properties of the artificial rock 100, the construction period in the ground improvement work can be shortened. In addition, since the amount of cement to be mixed and the buried soil 50 to be discarded, such as carry-in soil, can be reduced, construction costs can be reduced.
Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building 5, a ground improvement method that can suppress the construction period and construction cost while obtaining the embedding effect. Can be provided.

Moreover, from the analysis result of the dynamic analysis 1, the width of the ground improvement range 1 in a predetermined direction on the horizontal plane is set to be substantially the same as the width D of the underground portion of the nuclear related building 5 in the predetermined direction.
Thereby, for example, since the width | variety of the ground improvement range 1 can also be narrowed in the part where the width | variety D of the underground part of the nuclear power related building 5 is narrow, the placement range of the artificial bedrock 100 can be further limited.
Therefore, even if there is no bedrock 2 up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building 5, the ground improvement that can further reduce the construction period and construction cost while obtaining the embedding effect A construction method can be provided.

Further, based on the analysis result of the dynamic analysis 2, the ground improvement range is divided into a first range in contact with the nuclear-related building and a second range in contact with the outside of the first range. A second artificial rock mass having a shear wave velocity lower than that of the first artificial rock mass to be cast in the range is cast.
Thereby, for example, the amount of cement per 1 m ³ of the second artificial rock 110 in the second range 11 can be made smaller than the amount of cement per 1 m ³ of the first artificial rock 100 in the first range 10. Construction costs for ground improvement work can be reduced.
Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building 5, the ground improvement method that can further reduce the construction period and construction cost while obtaining the embedding effect. Can provide.

Further, from the analysis result of the dynamic analysis 2, the width of the first range 10 in the predetermined direction on the horizontal plane and the width of the second range 11 in the predetermined direction are determined based on the underground portion of the nuclear related building 5 in the predetermined direction. Narrower than width D.
Thereby, the construction cost of the ground improvement work is further suppressed by suppressing the width of the first range 10 of the first artificial rock 100 and the width of the second range 11 of the second artificial rock 110 to a width narrower than the width D of the underground portion. be able to.
Therefore, even if there is no bedrock up to the embedding depth level where the embedding effect can be obtained at the planned construction site of the nuclear related building 5, the ground improvement construction method that can further reduce the construction period and construction cost while obtaining the embedding effect. Can provide.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the said embodiment, although the width | variety of the 1st range 10 of the 1st artificial rock 100 and the 2nd range 11 of the 2nd artificial rock 110 is 0.5D which is substantially half of the width D of an underground part, The invention is not limited to this, and if the width of the first range 10 and the second range 11 is narrower than the width D of the underground portion, for example, the first range 10 is set to 2 / 3D, and the width of the second range 11 Can be 1 / 3D.

DESCRIPTION OF SYMBOLS 1 Ground improvement range 10 1st range 100 1st artificial rock mass 11 2nd range 110 2nd artificial rock mass 2 Rock mass 5 Nuclear-related building

Claims (4)

If the nuclear-related buildings Oite to the planned construction site of, the surface of the bedrock with the support performance for the nuclear-related buildings, does not reach the reference plane,
A surrounding underground portion in the nuclear architecture, Oite the ground improvement range extending to the specified horizontal plane on the basis of the width of the underground portion, the surface of the rock and drilling Umado covering the surface of the rock It is a ground improvement method that exposes and places artificial rock from the ground surface of the rock to the reference plane ,
A ground improvement construction method characterized in that a width of the ground improvement range in a predetermined direction on a horizontal plane is substantially the same as a width of the underground portion in the predetermined direction . The ground improvement range is
A first range in which a first artificial rock having a predetermined shear wave velocity is placed and is in contact with the nuclear related building;
Second artificial rock with low shear wave velocity than the predetermined shear wave velocity is pouring, ground according to claim 1, characterized in Rukoto that having a second range adjacent to the outside of the first range Improved construction method. In the planned construction site of a nuclear related building, when the ground surface of the rock mass that has the supporting performance for the nuclear related building does not reach the reference plane,
In the ground improvement range that extends around the underground portion of the nuclear-related building and spreads on the horizontal plane specified based on the width of the underground portion, the ground covering the surface of the bedrock is excavated to expose the surface of the bedrock. From the ground surface of the bedrock to the reference surface, a ground improvement method for placing artificial rock,
The ground improvement range is
A first range in which a first artificial rock having a predetermined shear wave velocity is placed and is in contact with the nuclear related building;
The second artificial rock having a predetermined low shear wave velocity than the shear wave velocity is pouring, the earth plate improved method you; and a second range adjacent to the outside of the first range.   The ground improvement according to claim 3, wherein a width of the first range in a predetermined direction on a horizontal plane and a width of the second range in the predetermined direction are narrower than the width of the underground portion in the predetermined direction, respectively. Construction method.

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