JP6450253B2 - Installation method of buried design device and buried structure of buried design device - Google Patents

Description

  The present invention relates to an installation method of an embedded design device for burying an embedded design device in the ground and an embedded structure of the embedded design device.

  As a technique in such a field, the earth pressure gauge installation method disclosed in Patent Document 1 is known. In this installation method, a buried material is laid on the foundation ground and a slope having a predetermined gradient, and a compacting operation using a heavy machine such as a rolling compactor is performed on the buried material. Next, a soil pressure gauge is placed on the buried material after the compacting operation. Then, a new buried material is laid on the earth pressure, and the new buried material is compacted using a heavy machine.

JP 2004-316269 A

  In general, as in the earth pressure gauge installation method disclosed in Patent Document 1, a static or dynamic load is applied to the buried material using a heavy machine in a compacting operation. If this static or dynamic load is applied to the earth pressure gauge through the buried material or directly, a malfunction may occur in the earth pressure gauge. Therefore, in order to suppress the load applied to the earth pressure gauge, the operation of compacting the buried material around the earth pressure gauge is performed by, for example, an operator using a wooden mallet to solidify the buried material without using a heavy machine. Sometimes. However, according to the manual work, the time required for the compacting work becomes long.

  Therefore, the present invention provides an embedded design device installation method and an embedded design device embedment structure capable of efficiently burying an embedded design device while suppressing damage to the embedded design device during an embedded operation.

  One aspect of the present invention is an installation method for an embedded design device in which an embedded design device is embedded in the ground, the step of placing the embedded design device on an arrangement surface exposed to the atmosphere, and spraying a first soil material on the arrangement surface. Forming a surrounding portion surrounding the embedded design tool.

  According to this installation method, the surrounding portion surrounding the embedded design device placed on the arrangement surface is formed by spraying the first soil material. Since the surrounding portion formed by this spraying is already dense, there is no need to perform a compacting operation using heavy machinery. Therefore, since no load is applied to the embedded design tool due to the compacting operation, damage to the embedded design device during the embedding operation can be suppressed. The work time required for forming the surrounding portion by spraying is shorter than the time required for the manual compaction work. Therefore, the embedded design device can be embedded efficiently.

  The method for installing an embedded design device according to an aspect of the present invention further includes a step of forming a covering soil portion that covers the surrounding portion by covering the surrounding portion with a second soil material after the step of forming the surrounding portion. Also good. According to this step, the embedding depth of the embedding design device can be increased.

  The method for installing a buried design device according to an aspect of the present invention may further include a step of forming a trench having a placement surface in the embankment portion made of the third soil material before the step of placing the buried design device. . According to this step, the embedding depth of the embedding design device can be set to a desired depth.

  The method for installing a buried design device according to an aspect of the present invention is a method of placing a first soil material in the trench after the step of forming a trench and before the step of placing the buried design device. In the step of forming the arrangement surface, the first soil material containing particles having a maximum particle size smaller than the maximum particle size of the particles included in the third soil material is sprayed. Also good. On the surface of the trench, unevenness corresponding to the maximum particle size of the particles contained in the third soil material may appear. Therefore, the first soil material is sprayed into the trench. The maximum particle size of the particles included in the first soil material is smaller than the maximum particle size of the particles included in the third soil material. When such a first soil material is sprayed, the first soil material enters the uneven surface on the surface of the trench, thereby leveling the uneven surface and obtaining a flat arrangement surface. Therefore, the buried design device can be suitably arranged.

  In the method for installing an embedded design device according to an aspect of the present invention, after the step of forming the surrounding portion, a step of forming a first covering soil portion around the surrounding portion, and on the first covering portion and the surrounding portion And a step of forming a second covering portion that covers the first covering portion and the surrounding portion. According to these steps, since the trench is not formed, there is no region that is affected by the formation of the groove such as the trench in the region where the buried design tool is buried. That is, since an operation such as digging up the densely formed region again is not performed, the region where the embedded design tool is embedded can be maintained in a suitable state.

  In the step of arranging the buried design device, a soil pressure gauge, a displacement meter, a settlement meter or a water pressure meter may be arranged as the buried design device. According to this process, the buried design tool corresponding to the purpose is selected, and the selected buried design tool is buried in the soil. Therefore, a desired measurement value such as earth pressure, displacement, subsidence amount or water pressure in the soil can be obtained.

  Another embodiment of the present invention is an embedding structure of an embedding design device in which the embedding design device is buried in the ground, the embedding design device arranged on the arrangement surface, and the embedding design device formed on the arrangement surface to surround the embedding design device. A surrounding portion, and the surrounding portion is formed by spraying a first soil material onto the arrangement surface.

  According to the method of installing an embedded design device and the embedded structure of the embedded design device of the present invention, the embedded design device can be embedded efficiently while suppressing damage to the embedded design device during the burying operation.

It is a figure which shows the cross section of the dam in which a buried design device is embed | buried. It is a perspective view which notches and shows a part of embedding area | region. It is sectional drawing which shows the main processes of the installation method of the buried design device which concerns on 1st Embodiment. It is a flowchart which shows the main processes of the installation method of the buried design device which concerns on 1st Embodiment. It is a graph which shows the relationship between a water content ratio and a dry density. It is a perspective view which shows an embedding area | region. It is sectional drawing which shows the main processes of the installation method of the buried design device which concerns on 2nd Embodiment. It is a flowchart which shows the main processes of the installation method of the buried design device which concerns on 2nd Embodiment. It is a top view which shows a modification. It is sectional drawing and a top view which show another modification.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
FIG. 1 shows a cross-sectional structure of the fill dam 100. The fill dam 100 is a kind of dam type, and is a large-scale structure composed of natural earth and sand and rocks. The fill dam 100 is a central core type rock fill dam, and includes a core 101, a filter 102, and a lock 103. The core 101 forms a water-impermeable zone having water barrier properties and is disposed at the center of the fill dam 100. For the core 101, a third soil material including an under material having a maximum particle size of about 50 mm is used. The core 101 is sandwiched between locks 103 that form a water-permeable zone having water permeability. The lock 103 supports the weight of the water W. For the lock 103, soil, rock, gravel, or the like is used. A filter 102 is disposed between the core 101 and the lock 103. The filter 102 is provided when the material is greatly different between the core 101 and the lock 103, and suppresses the outflow of the material constituting the core 101. Gravel or sand is used for the filter 102.

  The core 101 needs to maintain a predetermined water shielding property and strength over the construction and operation period of the fill dam 100. Therefore, in order to determine whether or not the core 101 maintains a preset water-imperviousness and strength, a plurality of embedded design tools 1 are embedded in the core 101. The buried design device 1 is, for example, a pore water pressure gauge. The pore water pressure gauge measures the water pressure in the core 101. The pore water pressure gauge has a filter on which the pore water pressure acts, and the displacement of the filter deformed by the pore water pressure is transmitted to the iron core disposed in the operating transformer via the pressure receiving portion. The position of the iron core in the operating transformer is converted into an electric signal, and the electric signal is transmitted to the outside of the core 101 via the cable 11 (see FIG. 2). These embedded design devices 1 are embedded in the core 101 using the embedded design device installation method according to one embodiment of the present invention.

  FIG. 2 is an enlarged perspective view showing the embedded structure A1 in which the embedded design device 1 is embedded in the core 101. FIG. The embedded structure A1 has an L-shaped trench 2 in plan view. The trench 2 is a groove having a trapezoidal cross section and a depth of about 700 mm. The width of the trench 2 becomes narrower toward the floor moat surface 3. In the trench 2, a floor layer 4, an embedded layer 6, and a covering layer (covering portion) 7 are stacked.

  The floor layer 4 is formed on the floor moat surface 3 of the trench 2 and has a thickness of about 100 mm. When the trench 2 is formed, unevenness having a maximum particle size of the soil material constituting the core 101 (for example, about 150 mm) may appear on the floor moat surface 3. Therefore, a substantially horizontal surface is formed by embedding this unevenness with the floor layer 4. For the floor layer 4, a second soil material having a maximum particle size of 20 mm is used.

  The buried layer 6 is formed on the floor layer 4 and has a thickness of about 300 mm. The buried layer 6 has a first buried portion 6a and a second buried portion 6b. The first embedded portion 6a is formed on the floor layer 4 so as to cover the embedded design device 1 and the cable 11 connected to the embedded design device 1. The first embedded portion 6a includes a base portion 6c, a surrounding portion 6d, and a cover portion 6e (see FIG. 3D). The foundation | substrate part 6c has the arrangement | positioning surface B in which the embedding design tool 1 is arrange | positioned. The surrounding part 6d is formed so as to surround the periphery of the embedded design device 1 on the arrangement surface B (see FIG. 3C). That is, the surrounding portion 6 d does not cover the upper surface of the embedded design device 1. The upper surface of the embedded design device 1 is covered with a cover 6e. The second embedded portion 6b is formed on the floor layer 4 and the first embedded portion 6a so as to cover the first embedded portion 6a. A first soil material may be used for the first burying portion 6a and the second burying portion 6b. The first soil material has a maximum particle size smaller than that of the second soil material. As an example, the maximum particle size of the second soil material is 20 mm, whereas the maximum particle size of the first soil material used for the buried layer 6 is about 5 mm. The maximum particle size of the soil material means the maximum particle size of particles (solid matter) contained in the soil material.

The characteristics of the first soil material will be described. The maximum particle size of the first soil material is 2 mm or more and 15 mm or less, preferably 5 mm. The maximum particle size is a particle size represented by the minimum nominal size of the sieve through which all the samples pass, and can be obtained by using a test method defined in Japanese Industrial Standards. The fine grain content is about 50% to 90%, preferably 65% to 85%. The fine particle content is the proportion of fine particles (particle size less than 0.075 mm) contained in the soil material (particle size less than 75 mm), and is obtained by a test defined in Japanese Industrial Standards. The plasticity index is 10 or more, preferably 20 or more and 40 or less. The plasticity index is the amount of water content in which fine particles contained in the soil material are in a plastic state, and can be obtained using a test method defined by the Geotechnical Society standards. Further, the value indicating the characteristics of the first soil material has a water content ratio, which will be described later. Examples of such a first soil material include man made soil and concrete mixed with cement at a predetermined ratio (for example, 50 kg or less per 1 m ³ ).

  Note that different soil materials may be used for the first embedded portion 6a and the second embedded portion 6b. For example, a first soil material may be used for the first embedded portion 6a, and a second soil material may be used for the second embedded portion 6b. In this case, the first embedded portion 6a serves as a buried portion, and the second buried portion 6b serves as a covering portion.

  The soil covering layer 7 is formed on the buried layer 6 and has a thickness of about 300 mm. A second soil material (maximum particle size 20 mm) is used for the soil covering layer 7 in the same manner as the floor layer 4. In addition, when different soil materials are used for the first embedded portion 6a and the second embedded portion 6b, the covering soil layer 7 has a third soil material (instead of the second soil material). A maximum particle size of 50 mm) may be used.

  Next, the main steps of the method for installing the buried design device will be described. FIG. 3 is a cross-sectional view showing the main steps of the installation method of the embedded design device 1. FIG. 4 is a flowchart showing the main steps of the installation method of the embedded design device 1. The installation method of the buried design device 1 is implemented as a part of the process of constructing the core 101 of the fill dam 100.

  First, as shown in FIG. 3A, a new embankment (filling portion) 13 is formed on the lower rolling layer 12 (FIG. 4: step S1). The height of the embankment 13 is 600 mm higher than the height at which the embedding design device 1 is installed. This embankment 13 is constructed according to a general construction method. Next, the trench 2 is formed (FIG. 4: step S2). The depth of the trench 2 is about 700 mm, which is 100 mm deeper than the depth at which the buried design tool 1 is installed. Further, the width H1 on the opening side is about 1200 mm, and the width H2 on the floor moat surface 3 side is about 600 mm. Remove large rocks from the floor moat surface 3 and carefully compact. Unevenness appears on the floor moat surface 3 of the trench 2.

  Next, as shown in FIG. 3B, the floor layer 4 is formed (FIG. 4: step S3). Here, a spraying method is used for forming the floor layer 4. The spraying method is a method for forming a region made of a spraying material by spraying the spraying material together with high-pressure air from a nozzle. The spraying method does not require a compacting operation using heavy machinery, does not damage the embedded design device 1 even when the spray material is directly sprayed onto the embedded design device 1, and covers a wide range. It can be used to convey spraying materials, can be applied to slopes and vertical surfaces without being limited to horizontal surfaces, can be applied to uneven surfaces, This has the advantage that the load on the pump is relatively small. The system used for the spraying method includes a compressor that supplies high-pressure air, a material supply unit that prepares the spray material, and an injection device that includes a nozzle 14 that injects the spray material together with the high-pressure air. In addition, it is preferable to provide a mixing unit that mixes the high-pressure air and the spray material so that the mixing can be performed satisfactorily. The compressor only needs to be able to supply high-pressure air necessary for injection, and a reciprocating or rotary compressor can be used. High pressure air having a pressure of about 1 MPa is supplied from the compressor. The nozzle 14 is injected with a mixture of the first soil material and high-pressure air from the tip thereof. The nozzle 14 is held by an operator 16, and the admixture is sprayed to a desired position by the operator 16 operating the direction of the nozzle 14.

  Note that the first soil material may be sprayed as an aggregate formed by an aggregate process. For example, the teeth of the pair of gears are engaged with each other with a predetermined gap and rotated at a constant speed. And if an admixture is thrown in between gears, an admixture will enter into the clearance gap between teeth, and it will be compressed and aggregated. Thus, according to the method of spraying the soil material as aggregates, the density of the soil in the region constructed by the spraying method can be further increased. In addition, when the aggregate is transported by the hose, even when the moisture content of the soil material constituting the aggregate is relatively high, compared to the case where the soil material is introduced into the hose as an admixture. The material can be prevented from adhering to the inside of the hose or nozzle. Therefore, the water content ratio of the soil material can be increased to such an extent that sufficient adhesion can be secured.

  Here, the water content ratio, which is a value indicating the characteristics of the first soil material, will be described. In a compacting operation using a heavy machine, a predetermined strength is ensured by expelling air in the gap in the soil material and increasing the density of the soil. In this embodiment, although a compacting operation using a heavy machine is not performed, a region in which the density of the soil is increased by a soil material spraying method is formed to ensure a predetermined strength. The soil condition is affected by the soil type, particle size, moisture content, energy provided by spraying, and the like. For example, even if the same amount of energy is applied, the strength of the soil after compaction is different if the water content ratio is different. Therefore, in the construction of a structure composed of a soil material, it is required to grasp the relationship between soil density and moisture content. The relationship between the density of soil and the water content can be obtained by a test defined in Japanese Industrial Standards.

FIG. 5 is a graph showing an example of the relationship between the water content ratio and the soil density. The horizontal axis indicates the moisture content, and the vertical axis indicates the dry density of the soil after spraying (or compaction). When the graph G1 is confirmed, it can be seen that there is one point where the dry density becomes maximum at a predetermined moisture content. The water content ratio at which the dry density is maximized is called the optimum water content ratio Wopt. The maximum dry density is called the maximum dry density ρ _dmax . The water content ratio of the soil material used in the spraying method of the present embodiment may be a value slightly smaller than the optimal water content ratio Wopt, or may be a water content ratio equal to or higher than the optimal water content ratio Wopt. The water content ratio of the soil material used in the spraying method of the present embodiment is set to a value within a predetermined range F. This range F is a range of −5% or more and + 40% or less with the optimal water content ratio Wopt as a reference value. Preferably, it is 0% or more and 30% or less. As an example, when the optimal moisture content of the soil material is 30%, the moisture content included in this range is + 25% or more and + 70% or less, and preferably + 30% or more and + 60% or less.

  Next, as shown in FIG. 3 (c), after digging a part of the floor layer 4 to form the arrangement groove 4a, the arrangement groove 4a is buried with a first soil material, thereby A base portion 6c of the embedded portion 6a is formed (FIG. 4: step S4). The spraying method is also used for forming the base portion 6c of the first embedded portion 6a. The water content ratio of the first soil material in the step S4 is 30% or more and 70% or less, and is 50% as an example. The first soil material is a 5 mm under material. The first soil material is sprayed to the arrangement groove 4a until the height of the base portion 6c (for example, about 50 mm) becomes substantially the same as that of the floor layer 4. Accordingly, since the surface of the base portion 6c becomes the arrangement surface B exposed to the atmosphere (see FIG. 3C), step S4 is a step of forming the arrangement surface. And as shown in FIG.3 (d), the embedding design tool 1 is mounted in the surface of the base | substrate part 6c which became substantially the same height as the floor layer 4 (FIG. 4: process S5). In addition, you may arrange | position washing sand etc. around the embedding design device 1 suitably. However, the first embedded portion 6a may be formed without digging the arrangement groove 4a, or the embedded design device 1 may be placed on the floor layer 4. In this case, the floor layer 4 is an arrangement surface exposed to the atmosphere. Moreover, you may acquire the initial value of the buried design tool 1 before arrangement | positioning of the buried design tool 1 as needed. Next, the first soil material is sprayed on the arrangement surface B until it becomes the same height as the embedded design device 1 to form the surrounding portion 6d surrounding the embedded design device 1 (FIG. 4: step S6). Subsequently, the first soil material is sprayed until the thickness of the layer reaches about 50 mm so as to cover the surrounding portion 6d and the embedded design device 1 to form the cover portion 6e of the first embedded portion 6a (FIG. 4: Step S7). In this spraying method, the sprayed soil materials are brought into close contact with each other by the kinetic energy possessed by themselves. Accordingly, the operator 16 can control the direction of the nozzles 14 to construct an arbitrary shape.

  Next, as shown in FIG. 3E, the second embedded portion 6b is formed (FIG. 4: step S8). For the construction of the second embedded portion 6b, the spraying method is used in the same manner as the first embedded portion 6a. The second embedding portion 6b may be subjected to a compacting operation using the compaction device 17 after spraying the first soil material by spraying. In this case, the striking force of the rolling device 17 may be smaller than the standard striking force. Then, as shown in FIG. 3F, the soil covering layer 7 is formed (FIG. 4: step S9). A compacting operation using a rolling device 17 is performed on the soil covering layer 7. In this case, the striking force of the compaction device 17 can be a standard value. Through the above steps S1 to S8, the embedding design device 1 is embedded in the soil.

  Here, after describing the installation method of the embedded design device according to the comparative example that has been conventionally performed, the operational effects of the installation method of the embedded design device according to the present embodiment will be described.

  In the method according to the comparative example, the worker performs the work of compacting the soil material around the embedded design device by hitting the soil material using a wooden hammer. Specifically, after the trench is formed, a floor layer is formed by laying a soil material including a 20 mm under material to a thickness of about 100 mm at the bottom of the trench. Next, after laying a soil material containing a 5 mm under material to a thickness of about 50 mm, the soil material is beaten with a wooden mallet and compacted. Next, the buried design device is placed on the compacted soil material. Next, after laying about 50 mm of a soil material including a 5 mm under material on the buried design device, the soil material is struck with a wooden mallet and compacted. Next, after laying a soil material including a 20 mm under material with a thickness of 100 mm or more, it is struck with a mallet and compacted. Next, after laying a soil material including a 20 mm under material to a thickness of about 300 mm, this time, the soil material is compacted by a compaction machine having a weak striking force. Then, after laying a soil material including a 50 mm under material to a thickness of about 300 mm, it is compacted by using a rolling machine having a standard striking force.

  Since the method according to the comparative example includes the compaction work by the operator's manual work, a great amount of labor and a long work time are required. Moreover, according to the manual work, the compacted state around the embedded design device tends to be non-uniform. If the compacted state is inhomogeneous, cracks or the like may occur at locations where the compacted state is weak as time passes. According to this crack or the like, the surrounding environment covering the embedded design device becomes more inhomogeneous. If it does so, there exists a possibility of causing the fall of the measurement precision by a buried design device. Further, since the earth pressure distribution acting on the buried design device varies, there may be a place where an excessive load acts on the buried design device.

  On the other hand, according to the installation method of the present embodiment, the buried layer 6 having the surrounding portion 6d surrounding the buried design device 1 placed on the placement surface B is formed by spraying the first soil material. . Since the buried layer 6 formed by this spraying is already densely formed, it is not necessary to perform a compacting operation using a heavy machine. Accordingly, since no load is applied to the embedded design device 1 due to the compacting operation, damage to the embedded design device 1 in the embedded operation can be suppressed. The work time required for forming the buried layer 6 by spraying is shorter than the time required for the manual compaction work. Therefore, the embedded design device 1 can be embedded efficiently.

  According to the spraying method of the present embodiment, it is possible to form the buried layer 6 in a compacted state without requiring hammering of a mallet or the like. Therefore, the compacted state of the buried layer 6 can be homogenized. When the compacted state is homogenized, the pressure applied to the embedding design device 1 is less likely to be biased, so that measurement data can be obtained with higher accuracy.

  According to the spraying method of the present embodiment, the operator needs to enter the trench 2 in order to perform the compacting operation of the first embedded portion 6a, for example, in addition to the operation of arranging the embedded design device 1. Absent. Accordingly, since it is not necessary to enlarge the trench 2 in order to secure a working space, the trench 2 can be made smaller. For example, in the case of the method according to the comparative example, the width H2 of the floor moat surface 3 requires about 600 mm, whereas in the method according to the present embodiment, it is sufficient if a width of +50 mm can be secured on both sides of the embedded design device. For example, about half of 300 mm is sufficient. If the trench 2 can be made smaller, the working time for forming the trench 2 can be shortened. Moreover, the time for refilling the trench 2 can be shortened by forming the first and second covering layers 9 in the trench 2.

  According to the spraying method of the present embodiment, the embedded layer 6 can be formed in a short time compared to manual work. Since a considerable number of buried design tools 1 are embedded in the core 101 of the fill dam 100, if the work time per buried design tool 1 is reduced, the work days can be reduced in units of several days in the entire dam construction. The effect is great.

  In the embedded design device installation method according to an embodiment of the present invention, the placement surface B is formed by spraying the first soil material onto the floor surface 3 of the trench 2. The maximum particle size of the particles included in the first soil material is smaller than the maximum particle size of the particles included in the third soil material. When such a first soil material is sprayed, the first soil material enters the uneven surface on the surface of the trench, so that the uneven surface is leveled and a flat arrangement surface B is obtained. Therefore, the buried design device 1 can be suitably arranged.

Second Embodiment
Next, the installation method of the buried design device according to the second embodiment will be described. The method according to the second embodiment is different from the method according to the first embodiment in that the embedded design device 1 is embedded without forming the trench 2.

  FIG. 6 is an enlarged perspective view showing the embedded structure A2 in which the embedded design device 1 is embedded by the embedded design device installation method according to the second embodiment. The embedded structure A2 has an L-shaped embankment 21 in plan view. The embankment 21 is formed on the lower rolling layer 22 and has a height of about 300 mm. The cross section of the embankment 21 has a trapezoidal shape. The cross-sectional shape of the embankment 21 is opposite to that of the trench 2 of the first embodiment, and the upper width H3 is smaller than the lower width H4. Further, the lower width H4 of the embankment 21 is about twice the height of the embankment 21. Therefore, when the height of the embankment 21 is 300 mm, the lower width H4 is about 600 mm.

  The embankment 21 has a buried layer 6 and a cover layer 23. The buried layer 6 is provided in a part on the lower rolling layer 22. Therefore, the embedded structure A2 includes the portion where the covering soil layer 23 is laminated on the lower rolling contact layer 22 along the height direction D2 of the embankment 21, the lower rolling contact layer 22, the embedded layer 6, and the covering soil layer 23. And a portion laminated in this order. The buried layer 6 includes a base portion 6c, a surrounding portion 6d, and a cover portion 6e (see FIG. 7). The foundation | substrate part 6c has the arrangement | positioning surface B in which the embedding design tool 1 is arrange | positioned. The surrounding part 6d is formed so as to surround the periphery of the embedded design device 1 on the arrangement surface B (see FIG. 7C). That is, the surrounding portion 6 d does not cover the upper surface of the embedded design device 1. The upper surface of the embedded design device 1 is covered with a cover 6e. The embedded structure A <b> 2 has a side cover soil layer 24 surrounding the embankment 21. The side covering soil layer 24 is provided on the lower rolling compaction layer 22 and has the same height as the embankment 21. On the embankment 21 and the side covering soil layer 24, an upper covering soil layer 26 (see FIG. 7F) formed by a normal construction process is provided.

  Next, main steps of the method for installing the buried design device according to the second embodiment will be described. FIG. 7 is a cross-sectional view showing the main steps of the installation method of the embedded design device 1. FIG. 8 is a flowchart showing the main steps of the installation method of the embedded design device 1.

  First, as shown in FIG. 7A, the lower rolling layer 22 is formed (FIG. 8: step S11). Next, as shown in FIG. 7B, after the part of the lower rolling layer 22 is dug to form the placement groove 22a, the placement groove 22a is buried with the first soil material to bury the placement groove 22a. A base portion 6c of the layer 6 is formed (FIG. 8: step S12). A spraying method is used for the operation of forming the base portion 6c. The first soil material is sprayed onto the arrangement groove 22a until the height of the base portion 6c becomes the same height as the surface of the lower rolling layer 22. Then, as shown in FIG. 7C, the embedded design device 1 is placed on the surface of the base portion 6c having the same height as the lower rolling layer 22 (FIG. 8: step S13). Accordingly, the lower surface of the buried layer 6 becomes the arrangement surface B exposed to the atmosphere (see FIG. 7B). However, the embedding design device 1 may be placed directly on the lower rolling layer 22. In this case, the lower rolling layer 22 becomes the arrangement surface B exposed to the atmosphere. Next, the first soil material is sprayed on the arrangement surface B until it becomes the same height as the embedded design device 1 to form the surrounding portion 6d surrounding the embedded design device 1 (FIG. 4: step S14). Subsequently, the first soil material is sprayed so as to cover the surrounding portion 6d and the embedded design device 1 to form the cover portion 6e of the embedded layer 6 (FIG. 8: step S15).

  Next, as shown in FIG. 7D, the soil covering layer 23 is formed by a spraying method (FIG. 8: step S16). In this spraying method, the sprayed soil materials are brought into close contact with each other by the kinetic energy of the spraying method. Therefore, when the operator 16 operates the nozzle 14, the quadrangular frustum-shaped covering soil indicated by the virtual line L is provided. It is possible to apply the layer 23. The soil covering layer 23 is preferably formed by spraying the first soil material. That is, the buried layer 6 and the soil covering layer 23 are formed of the same first soil material. In this case, the embankment 21 including the buried layer 6 and the covering soil layer 23 can be regarded as a buried portion.

  Next, as shown in FIG. 7E, a side cover soil layer (first cover soil portion) 24 is formed (FIG. 8: step S17). The side cover soil layer 24 is formed by laying a soil material on both sides of the embankment 21 and performing a normal rolling process. When performing the rolling process of the side soil covering layer 24, the soil covering layer 23 of the embankment 21 may be simultaneously rolled. Next, as shown in FIG. 7 (f), an upper soil covering layer (second soil covering portion) 26 is formed on the embankment 21 and the side portion soil covering layer 24 (FIG. 8: step S18). The upper soil covering layer 26 is formed by a known construction method.

  Through the above steps S11 to S18, the buried design device 1 is buried in the soil.

  Similarly to the method for installing the buried design device according to the first embodiment, the method for installing the buried design device according to the second embodiment forms the buried layer 6 by a spraying method. Therefore, it is possible to obtain the same effect as the method for installing the embedded design device according to the first embodiment.

  Moreover, in the installation method of the buried design tool according to the second embodiment, there is no step of forming the trench 2. Therefore, the work time for forming the trench 2 can be made unnecessary.

  Moreover, since the trench 2 is not formed in the method for installing the buried design tool according to the second embodiment, the buried structure A2 has no region that is affected by the formation of the groove such as the trench 2. Specifically, an operation such as digging up again after the compaction operation is performed on each region included in the embedded structure A2 is not performed. Accordingly, the compacted state of the region included in the embedded structure A2 can be kept good.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, in the first and second embodiments, the pore hydrometer is illustrated as an example of the buried design device 1, but the buried design device 1 is not limited to the pore water pressure meter, and various buried design devices can be selected according to the purpose. Can do. For example, as shown in FIG. 9A, a buried design device 1 </ b> A that is a soil pressure gauge may be disposed together with the pore water pressure gauge. A soil pressure gauge having a diaphragm method is embedded in the core 101 and measures soil pressure in the soil. The earth pressure gauge is arranged on the arrangement surface B in the vicinity of the pore water pressure gauge.

  Further, the arrangement surface B is not limited to the floor moat surface 3 of the trench 2. As shown in FIG. 9B, the arrangement surface B1 may be provided on the inclined surface 2a of the trench 2, and a soil pressure gauge may be arranged on each of the arrangement surfaces B1. Even if the arrangement surface B1 is the slope 2a, it is possible to easily form the buried layer by the spraying method. According to such an arrangement of the earth pressure gauge, it is possible to measure the earth pressure in the triaxial direction in the core 101.

  Moreover, as shown in FIG. 10A, the embedded layer 6A may be provided so as to penetrate the plurality of covering layers 23A to 23C. The plurality of soil covering layers 23 </ b> A to 23 </ b> C are stacked on the lower rolling layer 22. The soil covering layer 23 </ b> A is provided on the surface of the lower rolling layer 22. The soil covering layer 23B is provided on the surface of the soil covering layer 23A. The soil covering layer 23C is provided on the surface of the soil covering layer 23B. The embedded layer 6A extends in the vertical direction from the surface of the soil covering layer 23C to the surface of the soil covering layer 23A so as to penetrate the soil covering layers 23B and 23C. The buried design device 1B is disposed through the buried layer 6A, the covering soil layer 23A, and the lower rolling compaction layer 22 so as to extend in the vertical direction. According to such an embedded layer 6A, it becomes possible to install a layered settlement meter having a long shape along the vertical direction as the embedded design device 1B. The stratified settlement meter measures the settlement of each of a plurality of layers in the core 101. The stratum subsidence meter has a measuring rod whose tip is fixed to a rock or the like, and the amount of movement of the subsidometer using the measuring rod as a guide is measured as a change in sliding resistance.

  Further, as shown in FIG. 10B, a plurality of buried design devices 1 </ b> C may be arranged in one trench 2. According to such an arrangement, it is possible to suitably embed a rock formation displacement meter or the like that is preferably installed in a narrow area. The rock formation displacement meter measures the displacement and release strain of the rock mass.

  Further, as shown in FIG. 10C, the embedded structure A3 may include embedded portions 27 and 28 having different laminated structures arranged in parallel in the horizontal direction. The embedding parts 27 and 28 are juxtaposed in the horizontal direction on the floor layer 4. The embedded portion 27 includes a first embedded layer 27a provided on the floor layer 4 and a second embedded layer 27b provided on the first embedded layer 27a. The embedding design device 1D is disposed on the floor layer 4 and is embedded by the first embedding layer 27a. The embedded portion 28 includes a third embedded layer 28a provided on the floor layer 4 and a fourth embedded layer 28b provided on the third embedded layer 28a. According to the embedded structure A3 having the embedded portions 27 and 28, an interzone subsidence meter having a portion extending in the horizontal direction can be suitably arranged.

1, 1A, 1B, 1C, 1D ... buried design device, 2 ... trench, 3 ... floor moat surface, 4 ... floor layer, 4a, 22a ... placement groove, 6 ... buried layer, 6A ... buried layer, 7 ... covered soil layer, DESCRIPTION OF SYMBOLS 11 ... Cable, 12 ... Lower rolling layer, 13, 21 ... Filling, 14 ... Nozzle, 16 ... Worker, 17 ... Rolling device, 22 ... Lower rolling layer, 23, 23A, 23B, 23C ... Covering soil layer, 24 ... Side covering layer, 26 ... Upper covering layer, 27,28 ... Embedded portion, 100 ... Fill dam, 101 ... Core, 102 ... Filter, 103 ... Lock, A1, A2, A3 ... Embedded region, B, B1 ... Arrangement Surface, S2 ... a step of forming a trench, S4 ... a step of forming a base portion, S5 ... a step of placing a buried design device, S6 ... a step of forming an enclosing portion, S7 ... a step of forming a cover portion, S8 ... Step of forming the buried portion of 2, S9 ... Step of forming the covering layer

Claims (6)

A method for installing a buried design device in which a buried design device that is a earth pressure gauge, displacement meter, settlement meter or water pressure meter is buried in the ground
Placing the buried design device on a placement surface exposed to the atmosphere;
Forming a surrounding portion surrounding the embedded design device by spraying a first soil material on the arrangement surface. Before the step of arranging the embedded design device, further comprising the step of forming a base portion including the arrangement surface by spraying the first soil material,
In the step of forming the base portion, the first soil material including particles having a maximum particle size smaller than the maximum particle size of particles included in the soil material constituting the surface to which the first soil material is sprayed. The installation method of the buried design device according to claim 1, wherein After the step of forming the enclosure, the further comprises a step of forming a soil covering portion that covers the surrounding portion by covering the second soil material surrounding portion, the installation of a buried instrument according to claim 1 or 2 Method. Before the step of placing the buried design device, the first soil material is sprayed to form a trench including a bottom surface on which the foundation portion including the placement surface is formed in the embankment portion made of the third soil material. The installation method of the buried design device according to claim 2 or 3 , further comprising a step. After the step of forming the surrounding portion, forming a first cover soil portion around the surrounding portion;
On the first cover soil portion and the surrounding portion, the further comprises a step, to form a first second cover soil portion covering the soil covering portion and the surrounding portion, embedded according to claim 1 or 2 How to install the instrument. A buried design device embedded in the ground is a buried design device that is a earth pressure gauge, displacement meter, settlement meter or water pressure gauge ,
A buried design device disposed on a placement surface included in a base portion formed by spraying the first soil material ;
An encircling part formed on the arrangement and surrounding the embedding design tool,
The surrounding portion is formed by spraying the first soil material onto the arrangement surface.
Buried structure of buried design device.

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