Vibration-reducing temporary structure, its construction method, and its removal method
The vibration-reducing temporary structure uses expandable gas layer holding members to efficiently reduce vibrations and facilitate easy dismantling and reuse, addressing the inefficiencies of existing structures.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SUMITOMO MITSUI CONSTRUCTION CO LTD
- Filing Date
- 2022-10-14
- Publication Date
- 2026-06-29
AI Technical Summary
Existing vibration reduction structures for short-duration construction vibrations are difficult to remove and reuse due to the need for destruction or excavation, which is unsustainable and inefficient.
A vibration-reducing temporary structure using gas layer holding members that can expand and contract, allowing easy removal by deflating them after use, and a method for constructing and dismantling these structures to facilitate reuse.
The structure effectively reduces vibrations and can be easily dismantled and reused, minimizing waste and improving work efficiency by reducing the need for backfilling and excavation.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a vibration reduction temporary structure for reducing vibrations transmitted through the ground, and a construction method and a removal method thereof.
Background Art
[0002] Conventionally, as a countermeasure against vibrations transmitted through the ground, it has been known to excavate the ground between the vibration source side ground and the vibration receiving side ground to form an empty trench, and to block the vibrations with this empty trench. The empty trench has problems such as an increase in the area required for installation when a slope is provided as a landslide countermeasure, and a risk of people falling. Therefore, in the inventions described in Patent Documents 1 and 2, by making the side surface of the empty trench vertical and protecting it with a plate-like member, landslides are prevented and the installation area is reduced, and by providing a lid member, people are prevented from falling. In addition, in the invention described in Patent Document 3, a trench is formed by a high-rigidity wall body, and a vibration-proof material softer than the wall body is filled in the trench.
[0003] In addition, Patent Documents 4 to 7 describe reducing the transmission of vibrations by burying a member having an air layer in the ground.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Patent Document 3
[0005] The conventional technologies described above are suitable as countermeasures for vibrations that occur over relatively long periods, such as factory vibrations and traffic vibrations, and do not require removal. On the other hand, countermeasures for vibrations that occur over relatively short periods, such as construction vibrations, are often installed as temporary structures and require removal after the vibration-generating process is completed. Removing the vibration reduction structures described in Patent Documents 1 to 3 requires destroying plate-like members or walls. Furthermore, removing the vibration reduction structures described in Patent Documents 4 to 7 requires excavating the surrounding ground, and there is a high possibility that members with air layers will be damaged by heavy machinery during ground excavation, making it impossible to reuse the members. However, in recent years, there has been a demand to reduce waste and reuse members for sustainable development.
[0006] In view of the above background, the present invention aims to provide a vibration-reducing temporary structure, a method for constructing the same, and a method for dismantling the same, which can be easily removed for reuse. [Means for solving the problem]
[0007] To solve the above problems, one aspect of the present invention provides a method for constructing a vibration-reducing temporary structure (1, 21) for reducing vibrations transmitted through the ground (G), comprising: an excavation step of excavating an excavation trench (2) extending in a predetermined direction in the ground; a gas layer holding member placement step of arranging gas layer holding members (3, 11, 13, 22) in the excavation trench, which are capable of holding gas inside, allowing for the injection and discharge of the gas, and which expand when the gas is injected and contract when the gas is discharged, at least in the width direction of the excavation trench; and a gas injection step of injecting the gas into the gas layer holding members, which is performed before and / or after the gas layer holding member placement step.
[0008] According to this embodiment, the gas layer holding member deflates by releasing air, creating a gap between the gas layer holding member and the soil, allowing the gas layer holding member to be easily removed for reuse, and facilitating the removal of the vibration-reducing temporary structure.
[0009] In the above embodiment, the process may further include a support installation step, performed after the excavation step, in which a support (8) capable of supporting the gas layer holding members (3, 11, 13) arranged in the excavation trench (2) from the width direction is installed in the excavation trench (2), and a backfilling step, performed after the gas layer holding member placement step, the gas injection step, and the support installation step, in which the support is removed from the excavation trench while backfilling the space between the excavation trench and the gas layer holding members.
[0010] According to this embodiment, since the gas layer holding member is supported by the support, it is possible to prevent the gas layer holding member from falling over, thereby preventing obstruction of backfilling work.
[0011] In the above embodiment, at least a portion of the gas injection step may be performed after the gas layer holding member placement step, and may include injecting the gas into the gas layer holding members (3, 11, 13, 22) to bring the gas layer holding members into close contact with a pair of sides of the excavated trench (2) that are opposite to each other in the width direction.
[0012] According to this embodiment, backfilling work for constructing the vibration-reducing temporary structure becomes unnecessary or significantly reduced, thereby improving work efficiency. In addition, the frictional force between the gas layer holding member and the excavated trench increases, suppressing the lifting of the gas layer holding member due to rainwater, etc.
[0013] In the above embodiment, the gas layer holding member (13) may include a plurality of sub-chambers (15) that are divided in the predetermined direction and extend in the vertical direction.
[0014] According to this embodiment, since the inside of the gas layer holding member is divided, when gas is injected into the gas layer holding member, the center of the side surface in the thickness direction of the gas layer holding member does not bulge out compared to its surroundings.
[0015] One aspect of the present invention is a method for removing a vibration-reducing temporary structure (1, 21) constructed in the above aspect, comprising the steps of: discharging the gas from the gas layer holding members (3, 11, 13, 22) to shrink the gas layer holding members in the width direction; removing the gas layer holding members from the excavation trench (2); and backfilling the receiving trench (9), which is the space in the excavation trench where the gas layer holding members were received.
[0016] According to this embodiment, the gas layer holding member deflates by releasing air, creating a gap between the gas layer holding member and the soil, allowing the gas layer holding member to be easily removed for reuse, and the vibration-reducing temporary structure to be easily dismantled.
[0017] In the above embodiment, the gas layer holding member (3) comprises a plurality of tube bodies (5) extending in the vertical direction and connected to one another in the predetermined direction, each capable of holding the gas inside, allowing for the injection and discharge of the gas, and expanding when the gas is injected and contracting when the gas is discharged, at least in the width direction.
[0018] According to this embodiment, the gas layer holding member includes multiple tube bodies, thereby maintaining the soil pressure in the trench and securing an air layer, which suppresses vibration propagation.
[0019] In the above embodiment, the gas layer holding member may include the tube bodies arranged in two or more rows in the width direction.
[0020] According to this aspect, even if gas is not discharged from some of the tube bodies, gas is discharged from the tube bodies adjacent thereto, so that the gas layer holding member shrinks in the width direction of the excavation groove, creating a gap between the gas layer holding member and the earth and sand, and the gas layer holding member can be easily taken out.
[0021] In the above aspect, the gas layer holding member (22) includes a bag-shaped inner membrane (24) that defines a core layer (23) inside, a bag-shaped outer membrane (26) that houses the inner membrane inside and defines an outer peripheral layer (25) between the outer surface of the inner membrane, an injection / discharge port (27) that can select a state that allows and a state that restricts the flow of the gas between the outside of the gas layer holding member and the core layer, a communication path (28) having a check valve (30) that allows the flow of the gas from the core layer to the outer peripheral layer, and a discharge port (29) that can select a state that allows and a state that restricts the flow of the gas between the outer peripheral layer and the outside. The inner membrane is configured such that in a state where the gas is filled therein, the length in the width direction becomes shorter as it goes downward. The shrinking step may be performed by allowing the flow of the gas at the discharge port while restricting the flow of the gas at the injection / discharge port.
[0022] According to this aspect, when the gas layer holding member is taken out from the excavation groove, the gas layer holding member has a shape in which the length in the width direction becomes shorter as it goes downward, so that it is easy to take out the gas layer holding member.
[0023] An aspect of the present invention is a vibration reduction temporary structure (1, 21) for reducing vibration transmitted through the ground (G), which includes a receiving groove (9) provided in the ground and extending in a predetermined direction, and a gas layer holding member (3, 11, 13, 22) buried in the receiving groove, extending in the predetermined direction, and holding gas inside. The gas layer holding member can inject and discharge the gas, and expands by injecting the gas and shrinks by discharging the gas, at least with respect to the width direction of the receiving groove.
[0024] According to this embodiment, the gas layer holding member deflates when air is released, creating a gap between the gas layer holding member and the receiving groove. This allows the gas layer holding member to be easily removed for reuse, facilitating the removal of the vibration-reducing temporary structure. [Effects of the Invention]
[0025] According to the above embodiments, it is possible to provide a vibration-reducing temporary structure in which the components can be easily removed for reuse, as well as a method for constructing the same and a method for removing the same. [Brief explanation of the drawing]
[0026] [Figure 1] Perspective view showing a gas layer holding member according to the first embodiment. [Figure 2] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the first embodiment. [Figure 3] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the first embodiment. [Figure 4] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the first embodiment. [Figure 5] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the first embodiment. [Figure 6] Cross-sectional view showing the removal method of the vibration-reducing temporary structure according to the first embodiment. [Figure 7] Cross-sectional view showing the removal method of the vibration-reducing temporary structure according to the first embodiment. [Figure 8] Perspective view showing a gas layer holding member according to a first modified example of the first embodiment. [Figure 9] Perspective view showing a gas layer holding member according to a second modified example of the first embodiment. [Figure 10] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the second embodiment. [Figure 11] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the second embodiment. [Figure 12] Cross-sectional view showing the method for constructing a vibration-reducing temporary structure according to the second embodiment. [Figure 13] Cross-sectional view showing the removal method of the vibration reduction temporary structure according to the second embodiment. [Figure 14] Cross-sectional view showing the removal method of the vibration reduction temporary structure according to the second embodiment. [Figure 15] Cross-sectional view showing the removal method of the vibration reduction temporary structure according to the second embodiment. [Modes for carrying out the invention]
[0027] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the vibration reduction temporary structure 1 according to the first embodiment will be described with reference to Figures 1 to 7.
[0028] Figure 5 is a longitudinal cross-sectional view showing a vibration-reducing temporary structure 1 installed in the ground G. As shown in Figure 5, the vibration-reducing temporary structure 1 comprises an excavation trench 2 installed in the ground G, a gas layer holding member 3 placed inside the excavation trench 2, and a backfill section 4 of soil and sand backfilled into the excavation trench 2.
[0029] Figure 1 is a perspective view showing the gas layer holding member 3. As shown in Figure 1, the gas layer holding member 3 includes a plurality of tube bodies 5 extending in the vertical direction and injection / discharge ports 6 communicating with each of the tube bodies 5.
[0030] Each tube body 5 contains an outer membrane made of a flexible resin or the like. It expands when a gas such as air is injected into the outer membrane and deflates when the gas is released. Multiple tube bodies 5 are connected to each other in two rows in the thickness direction of the gas layer holding member 3 and in the length direction of the gas layer holding member 3. The multiple tube bodies 5 may also be arranged in one row in the thickness direction of the gas layer holding member 3, or in three or more rows.
[0031] The injection / discharge ports 6 are for injecting and discharging gas into and out of each tube body 5. The injection / discharge ports 6 have valves 7 that can select between a state that allows gas flow and a state that restricts gas flow. Instead of the injection / discharge ports 6 having valves 7, plugs (not shown) that can selectively close the injection / discharge ports 6 may be provided. The gas layer holding member 3 may have one injection / discharge port 6 that communicates with all the tube bodies 5, or it may have one injection / discharge port 6 for each tube body 5, or the tube body 5 may be divided into multiple blocks, with each block having one injection / discharge port 6 that communicates with all the tube bodies 5 belonging to that block.
[0032] The gas layer holding member 3 expands at least in the thickness direction when gas is injected into the plurality of tube bodies 5, and contracts at least in the thickness direction when gas is discharged from the plurality of tube bodies 5. When filled with gas, the gas layer holding member 3 is configured such that its vertical length is greater than or equal to the depth of the excavation trench 2. The gas layer holding member 3 may further include a long member (not shown) that extends vertically and has higher rigidity than the tube bodies 5 when not sufficiently filled with gas, or a plate-shaped or frame-shaped member (not shown) that extends vertically and in the direction of extension of the excavation trench 2 (see Figure 5), so that it can stand on its own when not sufficiently filled with gas into the tube bodies 5.
[0033] The construction and removal methods for the vibration-reducing temporary structure 1 will be explained with reference to Figures 2 to 7. Figures 2 to 5 show the construction method for the vibration-reducing temporary structure 1, and Figures 6 and 7 show the removal method for the vibration-reducing temporary structure 1. Figures 2 to 7 show cross-sections parallel to the vertical direction and the width direction of the excavation trench 2.
[0034] As shown in Figure 2, workers use heavy machinery such as a backhoe (not shown) to excavate the portion of the ground G between the vibration-generating ground (the construction site, etc.) and the vibration-receiving ground (the ground from which vibration transmission is to be reduced), thereby forming an excavation trench 2 extending in a predetermined direction. The predetermined direction may be straight or curved. Preferably, a pair of opposing sides in the width direction of the excavation trench 2 are parallel to the vertical direction.
[0035] Next, as shown in Figure 3, the worker positions the deflated gas layer retaining member 3 in the excavation trench 2 such that the tube body 5 extends vertically, the thickness direction of the gas layer retaining member 3 coincides with the width direction of the excavation trench 2, and the length direction of the gas layer retaining member 3 coincides with the extension direction of the excavation trench 2. The gas layer retaining member 3 abuts against the bottom surface of the excavation trench 2 at its lower end.
[0036] Next, as shown in Figure 4, the worker injects gas into each of the tube bodies 5 of the gas layer holding member 3, inflating the gas layer holding member 3 in the width direction of the excavation trench 2, and installs a support 8 within the excavation trench 2 that supports the gas layer holding member 3 from the width direction of the excavation trench 2. The support 8 is one or more elongated members that extend in the vertical direction, with its lower end piercing the bottom of the excavation trench 2 and its upper end protruding above the upper end of the gas layer holding member 3. The gas layer holding member 3 is sandwiched between one side of the excavation trench 2 and the support 8.
[0037] Furthermore, all or part of the gas injection into each tube body 5 of the gas layer holding member 3 may be performed before the gas layer holding member 3 is placed in the excavated groove 2. Also, the support 8 may be installed before the gas layer holding member 3 is placed in the excavated groove 2, in which case, at least part of the gas injection into the gas layer holding member 3 should be performed after the support 8 is installed.
[0038] Next, the workers remove the support 8 and use heavy machinery such as a backhoe (not shown) to backfill the space between the gas layer holding member 3 and the other side of the excavation trench 2 with soil or other material, forming a backfilled section 4 that fills the void in the excavation trench 2, as shown in Figure 5. In this way, the vibration-reducing temporary structure 1 is constructed. Hereinafter, the space defined by the ground G and the backfilled section 4 within the excavation trench 2, that is, the part in the excavation trench 2 where the gas layer holding member 3 is received, will be referred to as the receiving trench 9.
[0039] After the completion of the process that generates significant vibrations during construction, the workers discharge the gas from each of the tube bodies 5 of the gas layer holding member 3, as shown in Figure 6, causing the gas layer holding member 3 to deflate at least in the width direction of the excavation trench 2, and then remove the gas layer holding member 3 from the receiving trench 9.
[0040] Next, as shown in Figure 7, the workers use heavy machinery such as a backhoe (not shown) to backfill the receiving groove 9 with soil and sand, forming a post-removal backfill section 10 that fills the receiving groove 9. In this way, the vibration-reducing temporary structure 1 (see Figure 5) is removed.
[0041] The effects of the vibration-reducing temporary structure 1 will be explained with reference to Figures 1 to 7.
[0042] Because the gas layer holding member 3 contains gas inside, the transmission of vibrations from the exciting ground to the receiving ground is reduced by the vibration reduction temporary structure 1.
[0043] Even if a pair of opposing sides in the width direction of the excavation trench 2 are made parallel in the vertical direction in order to reduce the installation space for the vibration-reducing temporary structure 1, the excavation trench 2 can be filled immediately after excavation by the gas layer holding member 3 and the backfill section 4. As a result, landslides of the ground G defining the excavation trench 2 are less likely to occur, and the air layer formed in the excavation trench 2 is maintained.
[0044] By releasing gas from inside the gas layer retaining member 3, the gas layer retaining member 3 shrinks, creating a gap between the widthwise side surface of the receiving groove 9 and the gas layer retaining member 3. This allows the gas layer retaining member 3 to be easily removed from the receiving groove 9 without damage, making it reusable.
[0045] If the gas layer holding member 3 were plate-shaped and extended in the vertical direction and the direction of the extension of the excavation trench 2, a portion of the gas layer holding member 3 into which the gas is injected would collapse due to the earth pressure, potentially causing vibrations to be transmitted through that portion. However, since the gas layer holding member 3 includes multiple tube bodies 5, such a risk is reduced.
[0046] Since the tube bodies 5 extend in the vertical direction, there is less risk of gas discharge being obstructed by soil pressure compared to when they extend horizontally. Furthermore, if the tube bodies 5 are arranged in two or more rows in the width direction of the excavation trench 2, even if gas is not discharged from some of the tube bodies 5, if gas is discharged from tube bodies 5 adjacent to those tube bodies 5 in the width direction, a gap will be created between the width direction side surface of the receiving trench 9 and the gas layer holding member 3, allowing the gas layer holding member 3 to be easily removed from the receiving trench 9 without being damaged.
[0047] Since the gas layer holding member 3, which is placed in the excavation trench 2, is supported by the support body 8, it is possible to prevent the gas layer holding member 3 from falling over and thus hindering the backfilling work.
[0048] Figure 8 shows a gas layer retaining member 11 according to a first modification of the first embodiment. The shape of the gas layer retaining member 11 differs from that of the gas layer retaining member 3 described above, while the ability to pour in and discharge gas such as air is the same as that of the gas layer retaining member 3 described above. As shown in Figure 8, the gas layer retaining member 11 has thickness in the width direction of the excavation trench 2 (see Figure 5) and includes a plate-shaped bag that extends in the vertical direction and in the direction of extension of the excavation trench 2. Preferably, at least one surface of the gas layer retaining member 11 facing the thickness direction has a plurality of recesses 12 in order to mitigate the concentration of earth pressure in one place and to increase the frictional force with the ground G to resist buoyancy caused by rainwater, etc.
[0049] Figure 9 shows a gas layer holding member 13 according to a second modification of the first embodiment. The gas layer holding member 13 has thickness in the width direction of the excavation trench 2 (see Figure 5) and has a plate-like shape that expands in the vertical direction and in the direction of extension of the excavation trench 2. The inside of the gas layer holding member 13 is divided into a plurality of sub-chambers 15 by a partition membrane 14. The partition membrane 14 is connected to the upper and lower back surfaces of the outer membrane of the gas layer holding member 13, as well as the back surface of the side in the thickness direction, and the plurality of sub-chambers 15 are adjacent to each other in the direction of extension of the excavation trench 2. The gas layer holding member 13 is configured to allow the injection and discharge of gas to and from each sub-chamber 15 via an injection and discharge port 6. By providing a plurality of sub-chambers 15, when gas is filled into the gas layer holding member 13, the center of the side surface in the thickness direction of the plate-shaped gas layer holding member 13 is suppressed from bulging compared to its periphery. Therefore, the gas layer retaining member 13 is suitable when gas is injected into the gas layer retaining member 13 before placing the gas layer retaining member 13 in the excavated trench 2.
[0050] Referring to Figures 10 to 15, the vibration reduction temporary structure 21 according to the second embodiment will be described. In this description, components similar to those in the first embodiment will be denoted by the same reference numerals as in the first embodiment, and their descriptions will be omitted.
[0051] As shown in Figure 12, the vibration reduction temporary structure 21 according to the second embodiment comprises an excavation trench 2 provided in the ground G and a gas layer holding member 22 disposed within the excavation trench 2. The gas layer holding member 22 has a thickness in the width direction of the excavation trench 2 and exhibits a plate shape that expands in the vertical direction and in the direction of extension of the excavation trench 2. The gas layer holding member 22 includes a bag-shaped inner membrane 24 that defines a core layer 23 inside, a bag-shaped outer membrane 26 that houses the inner membrane 24 inside and defines an outer peripheral layer 25 between itself and the outer surface of the inner membrane 24, an injection / discharge port 27 that connects the outside of the gas layer holding member 22 to the core layer 23, a communication passage 28 that connects the core layer 23 to the outer peripheral layer 25, and an outlet 29 that connects the outer peripheral layer 25 to the outside of the gas layer holding member 22.
[0052] The bag-shaped inner membrane 24 and outer membrane 26 are made of a resin or the like, and expand when a gas such as air is injected into them, at least in the thickness direction, and contract when the gas is released. The outer membrane 26 defines the main part of the outer shape of the gas layer holding member 22 and, when filled with gas, generally exhibits a rectangular parallelepiped shape that is flattened in the thickness direction. The thickness of the outer membrane 26 is preferably thicker than the width of the excavation trench 2 when filled with gas in an unrestrained state. The vertical length of the outer membrane 26 when filled with gas is greater than or equal to the depth of the excavation trench 2. The inner membrane 24, when filled with gas, exhibits a plate shape with a smaller outer shape than the outer membrane 26 when filled with gas, and its upper surface has a thickness less than the width of the excavation trench 2, with its thickness decreasing towards the bottom.
[0053] The injection / discharge port 27 is for injecting and discharging gas such as air into and out of the core layer 23. The discharge port 29 is for discharging gas from the outer layer 25. The injection / discharge port 27 and the discharge port 29 have valves 7 that can select between a state that allows gas flow and a state that restricts gas flow. Instead of valves 7, plugs (not shown) may be provided at the injection / discharge port 27 and the discharge port 29. The communication passage 28 has a check valve 30 that allows gas to flow out from the core layer 23 to the outer layer 25 but restricts gas flow in the reverse direction. Therefore, when gas is injected from the injection / discharge port 27, the core layer 23 and the outer layer 25 are filled with gas, and when gas is discharged from the discharge port 29, gas is discharged from the outer layer 25 and the core layer 23. Note that gas from the core layer 23 can also be discharged from the injection / discharge port 27.
[0054] The construction and removal methods for the vibration-reducing temporary structure 21 will be explained with reference to Figures 10 to 15. Figures 10 to 12 show the construction method for the vibration-reducing temporary structure 21, and Figures 13 to 15 show the removal method for the vibration-reducing temporary structure 21. Figures 10 to 15 show cross-sections parallel to the vertical direction and the width direction of the excavation trench 2.
[0055] First, the workers excavate the ground G in the same manner as in the first embodiment to form the excavation trench 2. Next, as shown in Figure 10, the workers position the deflated gas layer holding member 22 in the excavation trench 2 such that the injection outlet 27 and outlet 29 are located at the top, its length coincides with the direction of extension of the excavation trench 2, and its thickness coincides with the width direction of the excavation trench 2. The gas layer holding member 22 abuts against the bottom surface of the excavation trench 2 at its lower end.
[0056] Next, as shown in Figure 11, the worker injects a gas such as air into the inner membrane 24 from the injection port 27 with the valve 7 of the outlet port 29 closed. A portion of the gas injected into the inner membrane 24 remains within the inner membrane 24 to form the core layer 23, and the remainder is injected between the inner membrane 24 and the outer membrane 26 through the connecting passage 28 to form the outer peripheral layer 25. Injection of gas from the injection port 27 is continued as shown in Figure 12 until it can be estimated that the gas layer holding member 22 has spread to substantially the entire depth and width of the excavation trench 2. The timing of completion of gas injection is controlled, for example, by the pressure at the injection port 27 and outlet port 29. At this time, the pressure in the core layer 23 and outer peripheral layer 25 is greater than atmospheric pressure, and this pressure causes the gas layer holding member 22 to contact the side surface of the excavation trench 2. After the injection of gas from the injection port 27 is completed, the worker closes the valve 7 of the injection port 27. In this way, the vibration-reducing temporary structure 21 is constructed. Part of the gas injection from the injection / discharge port 27 may be performed before the placement of the gas layer holding member 22 into the excavated trench 2. In the second embodiment, the excavated trench 2 is also the receiving trench 9.
[0057] After the completion of a process that generates significant vibrations during construction, the workers open the valve 7 of the discharge port 29, as shown in Figure 13, to discharge gas from the outer layer 25. At this time, the gas in the core layer 23 flows to the outer layer 25 through the connecting passage 28 due to the pressure difference between the core layer 23 and the outer layer 25. However, after the pressure in the core layer 23 drops to near atmospheric pressure, it becomes difficult for the gas to flow from the core layer 23 to the outer layer 25. As a result, the inner membrane 24 does not shrink significantly, and its shape, which narrows in the thickness direction as it goes downwards, is generally maintained, while the outer membrane 26 shrinks more significantly than the inner membrane 24. The gas layer holding member 22 as a whole shrinks to a shape that follows the shape of the inner membrane 24, which is generally maintained, and moves away from the side surface of the excavation trench 2.
[0058] Next, the worker removes the gas layer holding member 22 from the excavated trench 2, as shown in Figure 14. The removed gas layer holding member 22 may be deflated by opening the valve 7 of the injection / discharge port 27 and releasing the gas from the core layer 23, in order to facilitate transportation and storage.
[0059] Next, as shown in Figure 15, the workers use heavy machinery such as a backhoe (not shown) to backfill the excavated trench 2 (receiving trench 9) with soil and sand to form the post-removal backfilled section 31. In this way, the vibration-reducing temporary structure 21 (see Figure 12) is removed.
[0060] The effects of the vibration-reducing temporary structure 21 will be explained with reference to Figures 10 to 15.
[0061] The vibration-reducing temporary structure 21 according to the second embodiment reduces the transmission of vibrations from the exciting ground to the receiving ground, makes it less likely for the excavated trench 2 to collapse when the vibration-reducing temporary structure 21 is constructed, and allows the gas layer holding member 22 to be reused after removal.
[0062] Because there is a communication passage 28 with a check valve 30 between the core layer 23 and the outer layer 25, when gas is injected from the injection / discharge port 27 communicating with the core layer 23, the gas fills not only the core layer 23 but also the outer layer 25.
[0063] As the gas layer holding member 22 expands until it contacts both of the opposing sides of the excavation trench 2, there is no portion corresponding to the backfill section 4 (see Figure 5) of the first embodiment when constructing the vibration-reducing temporary structure 21, and filling and compacting soil in the backfill section 4 becomes unnecessary. In addition, as the expansion pressure of the gas layer holding member 22 is applied to the sides of the excavation trench 2 in the width direction, the frictional force between the sides of the gas layer holding member 22 in the thickness direction and the sides of the excavation trench 2 in the width direction increases, suppressing the lifting of the gas layer holding member 22 due to rainwater, etc.
[0064] Because the gas layer retaining member 22 has a shape that becomes thinner towards the bottom when removed from the excavation trench 2, the gas layer retaining member 22 can be easily removed during demolition. In other words, the sides of the excavation trench 2 in the width direction are closer to the sides of the gas layer retaining member 22 in the thickness direction towards the top, making them less likely to collapse. Even if they do collapse, because the thickness of the gas layer retaining member 22 becomes thinner towards the bottom, the collapsed soil and sand are less likely to get stuck between the sides of the gas layer retaining member 22 in the thickness direction and the sides of the excavation trench 2 in the width direction, and are more likely to fall downwards. This suppresses the increase in frictional force between the gas layer retaining member 22 and the excavation trench 2 due to soil and sand clogging. [Examples]
[0065] The effects of the vibration-reducing temporary structure 1 of the first embodiment and a void trench were compared. In a rectangular excavation trench 2 with a width of 0.8 m, a depth of 1.2 m, and a length of 10 m in longitudinal cross-section, a gas layer holding member 3 with a width of 0.1 m was placed with air injected, and the excavation trench 2 was backfilled to construct the vibration-reducing temporary structure 1. In addition, a rectangular void trench with a width of 0.8 m, a depth of 1.2 m, and a length of 10 m in longitudinal cross-section was constructed.
[0066] The vibrations of the ground G without any countermeasures against backhoe travel vibrations and the ground G equipped with a vibration-reducing temporary structure 1 and a trench were measured, and vibration levels were calculated and 1 / 3 octave band analysis was performed in the width, length, and vertical directions.
[0067] The vibration reduction effect of the vibration-reducing temporary structure 1 and the air trench was approximately equivalent in the vertical direction, at about 8 dB, and the dominant frequency of the effect was also similar at 31.5 Hz. This confirms that the vibration-reducing temporary structure 1 has the same vibration reduction effect as the air trench.
[0068] This concludes the description of specific embodiments, but the present invention is not limited to the above embodiments or modifications and can be broadly modified and implemented. In the first embodiment, if the gas layer holding members 3, 11, 13 include long, rigid members, plate-shaped members, or frame-shaped members, etc., so as to be self-supporting within the excavated trench 2, the installation of the support 8 may be omitted. In the first embodiment, all or part of the gas injection into the gas layer holding members 3, 11, 13 may be performed after the gas layer holding members 3, 11, 13 are placed in the excavated trench 2, and the gas layer holding member 3, 11 may be brought into close contact with a pair of side surfaces in the width direction of the excavated trench 2 by the injection of gas into the gas layer holding member 3, 11, and the installation and removal of the support 8 may be omitted. In this case, the receiving groove 9 coincides with the excavated trench 2, and backfilling work to form the backfilled section 4 becomes unnecessary or the amount of work is significantly reduced, thus improving work efficiency. In the second embodiment, the support 8 may be installed and the backfill section 4 may be provided. In this case, all of the gas may be injected into the gas layer holding member 22 before it is placed in the excavation trench 2. The second embodiment may be combined with the first or second modification of the first embodiment. [Explanation of symbols]
[0069] 1.21: Temporary structure for vibration reduction 2: Excavated trench 3,11,13,22: Gas layer retaining member 5: Tube body 8:Support 9: Receptor groove 15: Branch Office 23: Core Layer 24: Endometrium 25: Outer layer 26 : Adventitia 27: Inlet / outlet 28:Communication path 29: Outlet 30: Check valve G: Ground
Claims
1. A method for constructing a temporary vibration-reducing structure to reduce vibrations transmitted through the ground, An excavation step of excavating an excavation trench extending in a predetermined direction in the ground, A gas layer holding member placement step involves arranging a gas layer holding member in the excavation trench, which is capable of holding gas internally, allowing for the injection and discharge of the gas, and which expands when the gas is injected and deflates when the gas is discharged, at least in the width direction of the excavation trench; A gas injection step, performed before and / or after the gas layer holding member placement step, in which the gas is injected into the gas layer holding member. Equipped with, The gas layer holding member is, (i) A plurality of tube bodies extending in the vertical direction and connected to one another in the predetermined direction, each capable of holding the gas inside, capable of injecting and discharging the gas, and including a plurality of such tube bodies that expand when the gas is injected and deflate when the gas is discharged, at least in the width direction, (ii) A construction method comprising: a bag-shaped inner membrane defining a core layer inside; a bag-shaped outer membrane housing the inner membrane and defining an outer peripheral layer between itself and the outer surface of the inner membrane; an injection / discharge port that can select between allowing and restricting the flow of the gas between the outside of the gas layer holding member and the core layer; a communication passage having a check valve that allows the flow of the gas from the core layer to the outer peripheral layer; and an outlet that can select between allowing and restricting the flow of the gas between the outer peripheral layer and the outside, wherein the inner membrane is configured such that, when filled with the gas, its length in the width direction decreases as it goes downward.
2. A method for constructing a vibration-reducing temporary structure for reducing vibrations transmitted through the ground, An excavation step of excavating an excavation trench extending in a predetermined direction in the ground, A gas layer holding member placement step involves arranging a gas layer holding member in the excavation trench, which is capable of holding gas internally, allowing for the injection and discharge of the gas, and which expands when the gas is injected and deflates when the gas is discharged, at least in the width direction of the excavation trench; A gas injection step, performed before and / or after the gas layer holding member placement step, in which the gas is injected into the gas layer holding member. Equipped with, A support installation step is performed after the excavation step, in which a support capable of supporting the gas layer holding member, which is positioned in the excavation trench, from the width direction is installed in the excavation trench, A construction method further comprising a backfilling step, performed after the gas layer holding member placement step, the gas injection step, and the support installation step, in which the support is removed from the excavation trench while backfilling the space between the side surface of the excavation trench and the gas layer holding member.
3. The construction method according to claim 1, wherein at least a portion of the gas injection step is performed after the gas layer holding member placement step, and includes injecting the gas into the gas layer holding member to bring the gas layer holding member into close contact with a pair of sides of the excavated trench that are opposite to each other in the width direction.
4. The construction method according to claim 1, wherein the gas layer holding member includes the tube bodies arranged in two or more rows in the width direction.
5. A method for removing a temporary vibration-reducing structure for reducing vibrations transmitted through the ground, The vibration-reducing temporary structure comprises a receiving groove provided in the ground and extending in a predetermined direction, and a gas layer holding member embedded in the receiving groove, extending in the predetermined direction and holding gas inside, The gas layer holding member is capable of injecting and discharging the gas, and expands when the gas is injected and deflates when the gas is discharged, at least in the width direction of the receiving groove. The aforementioned removal method is: The steps include: discharging the gas from the gas layer holding member and shrinking the gas layer holding member in the width direction; The steps include removing the gas layer holding member from the receiving groove, The step of backfilling the aforementioned receiving groove Equipped with, A removal method comprising a plurality of tube bodies, each extending in the vertical direction and connected to one another in the predetermined direction, each capable of holding the gas inside, capable of injecting and discharging the gas, and expanding when the gas is injected and contracting when the gas is discharged, at least in the width direction.
6. The removal method according to claim 5, wherein the gas layer holding member includes the tube bodies arranged in two or more rows in the width direction.
7. A method for removing a temporary vibration-reducing structure for reducing vibrations transmitted through the ground, The vibration-reducing temporary structure comprises a receiving groove provided in the ground and extending in a predetermined direction, and a gas layer holding member embedded in the receiving groove, extending in the predetermined direction and holding gas inside, The gas layer holding member is capable of injecting and discharging the gas, and expands when the gas is injected and deflates when the gas is discharged, at least in the width direction of the receiving groove. The aforementioned removal method is: The steps include: discharging the gas from the gas layer holding member and shrinking the gas layer holding member in the width direction; The steps include removing the gas layer holding member from the receiving groove, The step of backfilling the aforementioned receiving groove Equipped with, The gas layer holding member includes a bag-shaped inner membrane defining a core layer inside, a bag-shaped outer membrane housing the inner membrane and defining an outer peripheral layer between it and the outer surface of the inner membrane, an injection / discharge port that can select between allowing and restricting the flow of the gas between the outside of the gas layer holding member and the core layer, a communication passage having a check valve that allows the flow of the gas from the core layer to the outer peripheral layer, and an outlet that can select between allowing and restricting the flow of the gas between the outer peripheral layer and the outside. The inner membrane is configured such that, when filled with the gas, its length in the width direction decreases as it goes downwards. The removal method is carried out by allowing the flow of the gas at the outlet while restricting the flow of the gas at the injection outlet, in the deflation step.
8. A temporary vibration reduction structure for reducing vibrations transmitted through the ground, A receiving groove provided in the ground and extending in a predetermined direction, A gas layer holding member embedded in the receiving groove, extending in the predetermined direction, and holding gas inside, Equipped with, The gas layer holding member is capable of injecting and discharging the gas, and expands when the gas is injected and deflates when the gas is discharged, at least in the width direction of the receiving groove. The gas layer holding member is, (i) A plurality of tube bodies extending in the vertical direction and connected to one another in the predetermined direction, each capable of holding the gas inside, capable of injecting and discharging the gas, and including a plurality of such tube bodies that expand when the gas is injected and deflate when the gas is discharged, at least in the width direction, (ii) A temporary vibration reduction structure comprising: a bag-shaped inner membrane defining a core layer inside; a bag-shaped outer membrane housing the inner membrane and defining an outer peripheral layer between itself and the outer surface of the inner membrane; an injection / discharge port that can select between allowing and restricting the flow of the gas between the outside of the gas layer holding member and the core layer; a communication passage having a check valve that allows the flow of the gas from the core layer to the outer peripheral layer; and an outlet that can select between allowing and restricting the flow of the gas between the outer peripheral layer and the outside, wherein the inner membrane is configured such that, when filled with the gas, its length in the width direction decreases as it goes downward.
9. The vibration reduction temporary structure according to claim 8, wherein the gas layer holding member includes the tube bodies arranged in two or more rows in the width direction.