JP2009235831A - Configuration of underground structure and construction method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress ground subsidence of ground surface at the time of construction of underground structure such as a crossing structure under road-railway without using a chemical grouting method. <P>SOLUTION: In a construction of underground structure such as a crossing structure under road-railway, an burial process of tabular member for burying a tabular member 530 along with both sides of top face of the underground structure which forms a space under the ground for construction and facing to the ground surface. By burying the tabular member 530, ground subsidence of the ground surface is prevented by suppressing collapse of peripheral ground, for example, at the time of construction of a pipe roof method as an auxiliary method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for suppressing subsidence on the ground surface side when a structure is constructed in the ground. In particular, this technique is effective when applied to the construction of structures that cross underground at a relatively shallow depth, such as roads and tracks.

  When constructing a crossing structure under a road / track, first, a start / reach shaft will be constructed beside the road / track. At the same time, an auxiliary construction method will be constructed to reduce the impact of the construction of the crossing structure under the road / track (the impact of ground excavation). As such an auxiliary construction method, a pipe roof construction method for increasing the rigidity of the ground, a chemical solution injection construction method for improving the ground, and the like are applied.

  The pipe roof construction method is used to prevent the occurrence of accidents such as damage or collapse due to ground subsidence when constructing tunnels directly under structures such as buildings, walkways, and railways on the ground. It is a construction work. For example, there are descriptions in Patent Documents 1 and 2.

In such a construction method, a steel pipe that can be adapted to an overload is installed directly under a target structure that requires protection, and is installed over a predetermined length, width, and depth using a hydraulically operated excavator while being joined by welding. Such steel pipe is filled with, for example, ready-mixed concrete, mortar, cement. This is a construction method that protects the structure on the ground from below in the ground. At the time of construction, for example, a horizontal orange construction method which is one of small diameter propulsion construction methods is applied.

  On the other hand, the chemical solution injection method is a method in which cement milk or water glass grout is injected into cavities, gaps, cracks, etc. in the ground to improve water-stopping and strengthen the ground. That is, the surrounding ground to be excavated is improved. Such a construction method is described in Patent Documents 3 and 4, for example.

After the construction of the auxiliary method, a guide guide pit for crossing is constructed at the lower part of the starting vertical shaft. In addition, a reaction wall will be constructed on the side of the starting vertical shaft. After constructing the reaction wall, construct the crossing frame and gradually build it while excavating it with the tip of the blade while propelling it with a jack.
JP 05-071292 A JP 2007-262680 A JP 2001-193383 A JP 2004-233891 A

  As mentioned above, when making a tunnel structure in the underground where the depth is relatively shallow, such as a road / railway crossing structure, before starting the actual excavation, the pipe roof method, or the chemical injection method, Or both are used together as an auxiliary construction method. However, among these auxiliary methods, the chemical injection method sometimes damages existing structures on the ground surface.

  For example, in a ground (viscous ground) with little gap in the ground and poor water permeability, the pore water pressure increases due to the injection of the chemical solution. Therefore, in some cases, the ground causes local shear failure. The injected material may penetrate into the gap of the local shear fracture, resulting in split injection. When split injection occurs in this way, the road or track is lifted, which hinders vehicle and train travel. At the same time, an incomplete injection site is created and the purpose of improving the surrounding ground cannot be achieved.

  In particular, it has been pointed out that in the ground improvement by chemical solution injection, the injection range of the chemical solution is unclear and the effect of ground improvement is small because the injection pressure cannot be increased so much because of the suppression of road surface elevation by the injection pressure. .

  On the other hand, when pipe roof construction is carried out for the purpose of increasing the rigidity of the ground, the hole through which the pipe passes is excavated to a slightly larger size, so that the surrounding earth and sand collapses, and ground subsidence inevitably occurs. Conventionally, such land subsidence has been suppressed by a chemical injection method. However, there is a possibility that the inconvenience described above may occur. Therefore, the present inventor considered that it was necessary to develop a method capable of suppressing ground subsidence without being based on the ground improvement by the chemical injection method.

  An object of the present invention is to suppress ground subsidence on the ground surface side during construction of underground structures such as road / railway crossing structures without using a chemical injection method.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The structure of the underground structure according to the present invention is a structure of an underground structure such as a road / railway crossing structure, and both sides on the upper surface side of the underground structure forming a space in the underground. A plate-like member is embedded along the surface side toward the ground surface side. In this configuration, a pipe roof is provided between the plate-like members. In any one of the configurations described above, the underground structure, the pipe roof, or the underground structure and the pipe roof are preliminarily planned to be constructed, and only the plate-like member is embedded. Features. In any one of the configurations described above, the underground structure traverses a surface-side road such as the existing road / railway.

  In addition, the construction method of the underground structure of the present invention is a construction method of the underground structure such as a road / railway crossing structure, etc., and is an underground structure that forms a space in the underground. It has a plate-like member embedding process of burying a plate-like member toward the ground surface side along both side surfaces on the upper surface side. In such a configuration, a pipe roof burying step of burying a pipe roof is provided after the plate-like member burying step. In this configuration, the plate member is embedded in a hole in the ground excavated by a wire saw. In such a configuration, the underground structure is constructed after the pipe roof burying step. In any one of the configurations described above, the underground structure traverses a surface-side road such as the existing road / railway.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  In the present invention, since the plate-like member is embedded, ground subsidence due to the collapse of the surrounding ground can be suppressed in the subsequent pipe roof construction method or construction of underground structures. Therefore, the subsidence suppression on the ground surface side can be performed accurately and easily at a low cost without using a chemical solution injection method as in the prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  The present invention relates to the structure of an underground structure and its construction method. In particular, it is effective when applied to a road / railway crossing structure. Furthermore, it is particularly effective when applied to an underground structure for crossing at a shallow depth of at least 3 m or less from the surface side. In a place where the depth is deeper than 3 m, there is usually little influence on subsidence of the surrounding ground.

  One of the features of the present invention is that a plate-like member is embedded in advance in the planned construction area of the underground structure when the underground structure is constructed. By embedding such a plate-like member, it is possible to suppress ground subsidence on the ground surface side by suppressing the landslide phenomenon in the underground during the subsequent auxiliary construction method, construction of underground structures, etc. . In particular, the effect can be remarkably confirmed in the case of sand. Since sandy embankments are frequently used on roads, railways, etc., it is effective for construction of underground structures that cross under roads, railways, etc. using such sandy embankments.

  That is, sandy embankments are generally performed on roads, ground-side roads such as trains, and the like. Such sandy embankments tend to collapse. However, the present invention can be effectively applied when a traffic path is provided in the ground so as to cross the lower side of such a traffic path. Even in sandy soils that are easy to collapse, the collapse can be effectively suppressed and construction of underground structures can be performed without hindering normal traffic.

  In addition, in the present invention, the plate-like member may be embedded in advance in accordance with the planned construction section of the underground structure in advance at the planned construction stage of the underground structure. In that case, a very unique structure is formed in which only the plate-like member is embedded.

  Hereinafter, the structure will be described in detail in Embodiment 1 and the construction method of the structure in Embodiment 2. In the description, a description will be given by taking as an example a configuration in which a road where a car can pass crosses under a road where a car can pass. For example, the underground structure is a completed image as shown in FIG. There is an existing road 100 on the ground surface through which automobiles can pass. A road 200 through which a car can pass by excavating the underground below the road 100 is provided. That is, the road 100 provided on the ground surface side and the crossing road 200 cross through the underground below the road 100.

  In the following embodiments, as described above, a case where roads 100 and 200 through which automobiles can cross each other in the ground will be described as an example. However, the present invention can be applied to such an example. It is not limited to. That is, at least one of the intersecting roads may be a road exclusively for people who cannot pass cars. Alternatively, it may be a railway on which tracks are laid. Alternatively, a road in which a person and a car, or a person, a car, and a railroad can be used together may be used.

(Embodiment 1)
The two roads 100 and 200 intersecting in the ground having the configuration shown in FIG. 1 are originally provided with the road 100 on the ground surface side. The need arises later for the existing road 100, and the road 200 is provided through the underground so as to pass under the existing road 100. When such a road 200 is provided in the transverse direction, it is required to pass through a place where the depth from the road 100 is shallow as much as possible. The deeper the depth, the more expensive the cost and the duration of the excavation. Therefore, in reality, excavation at a shallower depth is required. For example, there are usually many cases of about 1 to 3 m from the ground surface side. In FIG. 1, the road 200 is regarded as a crossing structure under the road.

  Such a road 200 excavates a vertical pit across the existing road 100 provided on the ground surface, as shown in the perspective view of the under-road crossing structure construction state in FIG. One is the starting shaft 300 and the other is the reaching shaft 400. The underground underground is excavated from the starting vertical shaft 300 toward the reaching vertical shaft 400, that is, in a direction crossing the road 100, and for example, a concrete casing 510 is used as a crossing structure of the underground structure 500. Provide. The inside of the casing 510 is configured to be passable.

  3A, a pipe roof 520 is provided on the upper surface side of the casing 510 by a pipe roof method as an auxiliary method. Furthermore, the plate-shaped member 530 according to the present invention is provided from the position of the upper surface 510a of the casing 510 toward the ground surface side. It is provided almost vertically. The plate-like member 530 is provided along the side surface 510b side of the casing 510. In the perspective view of FIG. 2, only a part of the casing 510, the pipe roof 520, and the plate-like member 530 constituting the underground structure 500 is shown for easy understanding.

  In order to embed the casing 510 in a predetermined direction, guide holes 510d are provided in advance at both ends of the bottom surface 510c of the casing 510 as shown in FIG.

  As shown in FIG. 3A, in this underground structure 500, a casing 510 formed in a square cylinder shape is embedded with the cylinder direction oriented in the transverse direction of the road 100. A pipe roof 520 is embedded above the upper surface 510 a of the casing 510. For example, as shown in FIG. 3A, a plurality of such pipe roofs 520 are provided in accordance with the upper surface 510a. The plurality of pipes 520a constituting the pipe roof 520 are formed, for example, in a steel pipe or the like, and are provided in the depth direction of the casing 510 as shown in FIG.

  Further, plate-like members 530 are provided on both end sides of the upper surface 510a of the casing 510 so as to sandwich a pipe roof 520 composed of a plurality of pipes 520a. For example, in the case shown in FIG. 3A, the plate-like member 530 is embedded with the lower end side from the end of the upper surface 520a and the upper end side facing the ground surface. As shown in FIG. 3B, the plate-like member 530 is embedded with a plurality of small pieces 530a connected to each other. That is, the plate-like member 530 formed on the small piece 530a is pushed in the cylindrical direction of the casing 510 so that the end faces thereof are sequentially aligned.

  For example, in the case shown in FIG. 3B, four small pieces 530a are connected and embedded to form a plate-like member 530. Of course, the plate-like member 530 may not be composed of a plurality of small pieces 530a but may be composed of a single sheet if possible. In the case shown in FIG. 3A, the plate-like member 530 is buried in the vertical direction, but as shown in FIGS. 3C and 3D, the ground can be prevented from collapsing obliquely upward. You may embed it at a slight angle in the range.

  For embedding the plate-like member 530, for example, a thin hole is opened in the cylindrical direction of the casing 510 using a wire saw, and the end faces of the small pieces 530a are sequentially aligned in the hole. Just add it. Thus, since the hole is cut first and then inserted, the direction of insertion can be straightened. In addition, since the hole has a size substantially matched to the end face of the plate-like member 530, it is necessary to insert the hole using a jack or the like.

  The plate member 530 is provided for the purpose of preventing the surrounding soil from collapsing when the pipe 520a of the pipe roof 520 is buried. Therefore, even when the casing 510 is embedded in the ground without providing the pipe roof 520, the plate member 530 may of course be embedded for the purpose of preventing the surrounding soil from collapsing during the embedding.

  Moreover, what is necessary is just to set suitably the thickness, magnitude | size, etc. of the plate-shaped member 530 within the range which can prevent the surrounding ground collapse. Further, the embedding direction is not limited to the vertical direction as described above, and may be slightly deviated from the vertical direction. In short, it is only necessary to effectively prevent the surrounding ground from collapsing.

  3A and 3B, the plate-like member 530 is embedded together with the pipe roof 520 and the casing 510 as described above. However, a method in which only the plate member 530 is embedded in advance is also conceivable. For example, as shown in FIGS. 4A to 4C, a structure in which only the plate member 530 is embedded in the ground below the existing road 100 may be used. In the case shown in FIG. 4A, the case where the state of embedding the plate-like member 530 in the ground from the road 100 side is seen in a plane is shown.

  FIG. 4B shows an embedded state of the plate-like member 530 in the cross-sectional direction indicated by the line AA in FIG. FIG. 4C shows an embedded state of the plate-like member 530 in the cross-sectional direction along the line BB in FIG. The plate-like member 530 shown in FIG. 4 can be effectively used when a pipe roof 520 and a casing 510 are provided thereafter to form the underground structure 500 that crosses under the road 100. As described above, the structure of the underground structure 500 may be a structure in which only the plate-like member 530 is embedded. At least two of the embedded plate-like members 530 are embedded with a predetermined interval.

  When embedding only the plate-like member 530, for example, excavating from the ground side with a wire saw in the vertical direction in the ground in accordance with the construction of the road on the ground side, the plate-like member 530 is placed there. You can embed it. Then, what is necessary is just to construct a road on the ground side as embankment etc. After the construction, at a necessary time, a vertical shaft is excavated, and a road / railway crossing structure may be constructed at a place where the plate-like member 530 is buried. Of course, the plate-shaped member may be embedded and installed by excavating a vertical shaft for embedding the plate-shaped member and further excavating the horizontal shaft after the road construction on the ground side.

  In the above description, the casing 510 has a rectangular cylindrical shape. However, other shapes can be used. For example, it may be cylindrical. In the case of the cylindrical shape, the plate-like member 530 may be raised from the both ends in the diameter direction toward the ground surface and embedded.

  In addition, the structure of the underground structure 500 described above is not limited to application to a road / railway crossing structure as shown in FIGS. 1 and 2, for example, as shown in FIG. It can also be applied as an auxiliary construction method for connecting and evacuation pits such as road tunnels where the earth covering is small and the surrounding ground is soft. That is, when excavating the connection mine and the evacuation mine, the plate-like member 530 is embedded so that the surrounding ground does not collapse. FIG. 5 schematically shows the situation. Of course, the pipe roof method may be used in combination. Normally, in the evacuation tunnel, the depth is assumed to be about 1D as shown in FIG.

  In the above description, the case where the plate-like member 530 is provided at two positions on both sides of the casing 510 has been described. However, three or more locations may be provided. For example, the upper surface 510a of the casing 510 is wider than the case shown in FIG. In the case where the width is wide, for example, one place may be added to the center portion of the pipe roof 520. Furthermore, when the width of the upper surface 510a is wider, a plurality of positions may be provided at both ends of the pipe roof 520 and in the middle of the pipe roof 520. At least two plate-like members 530 are required. One place may be considered as impossible in practice.

(Embodiment 2)
In the embodiment, the structure of the underground structure has been described in detail. In the present embodiment, a construction method for underground structures will be described. Although the structure of the underground structure has been described in detail in the first embodiment, how to construct the structure having such a configuration will be described. Of course, the construction method described below is one typical example, and the present invention is not limited to such an example.

  The construction method of the present invention is characterized in that when excavating the underground, there is a step of taking measures so that the ground surface does not sink due to the collapse of the surrounding ground. This countermeasure process is characterized by embedding a plate-like member. That is, the conventional chemical injection method is not used. By embedding the plate-like member, the abandonment of the surrounding ground into the space caused by excessive excavation during subsequent excavation is prevented. It prevents avalanche and suppresses land subsidence on the ground surface side.

  Therefore, subsequent excavation must be performed in principle within a range in which the collapse phenomenon of the surrounding ground of the plate member can be prevented. For example, when the pipe roof construction method is used as an auxiliary construction method, it is necessary that the plate-like members are embedded on both sides of the applicable range of the pipe roof construction method. In this way, the collapse of the surrounding ground is suppressed and ground subsidence on the ground surface side is prevented.

  The case where the plate-like member burying step functions effectively means that excavation with a covering of 3d or less is preferable when the steel pipe diameter of the pipe roof method is d. This is because when the earth covering is larger than 3d, the earth and sand collapse due to the excavation has almost no influence on the ground settlement on the ground surface side. Furthermore, when the ground collapse such as sandy soil and embankment is likely to occur, the effect is remarkable.

  The construction method of a series of underground structures including the plate-like member burying step having such a configuration is, for example, as shown in the flowchart of FIG. That is, as shown in step S100, the construction range of the underground structure crossing the road is confirmed. Check the construction drawing to see which part of the road 100 on the surface side is crossed.

  When the confirmation of the construction position of the underground structure is completed, as shown in step S200, vertical shafts are excavated at both ends of the road crossing position on the ground surface side. As shown in FIG. 2, for example, the vertical shaft digs a starting vertical shaft 300 and a reaching vertical shaft 400 at both ends of the crossing position of the road 100. The horizontal shaft is excavated from the starting vertical shaft 300 side toward the reaching vertical shaft 400 side.

  In the excavation of the horizontal shaft, first, in step S300, the horizontal shaft for embedding the plate member is excavated. In such excavation, for example, a wire saw is used because it is sufficient that a hole that can embed a plate-like member is formed. If such a wire saw is used, the hole can be a hole just about the end face of the plate-like member. What is necessary is just to select the kind of wire saw to use suitably according to the thickness of the end surface of the plate-shaped member to be used, height, etc. The size of the hole to be opened using a wire saw is preferably about the size of the end face of the plate-like member to be used. If a too large hole is made, the plate-like member provided for the purpose of preventing the surrounding ground from collapsing causes the surrounding ground to collapse and the meaning of the installation is lost. The hole is preferably such that the plate-like member can finally be pushed in with a jack or the like.

  Before drilling a hole with a wire saw, first, as shown in FIGS. 7A and 7B, a boring hole 10 is opened. The boring hole 10 is opened by the wire saw boring machine 11 along the side surface range of the underground structure from the starting vertical shaft toward the arrival vertical shaft. When the boring hole 10 has been opened, a wire saw 12 is formed by passing a wire through the boring hole 10 from the reaching shaft side. The ground is excavated with the formed wire saw 12. The hole opened by the wire saw 12 becomes, for example, a narrow vertically long hole 13 as shown in FIG. Since the excavation is performed along the borehole 10, it is accurately performed along the side surface of the underground structure.

  As shown in FIG. 8B, a small piece 20 a made of a steel plate or the like is inserted as a plate-like member 20 into the hole 13 opened by the wire saw 12. When inserting, since the hole 13 opened by the wire saw 12 is almost the same size as the end face of the small piece 20a, the jack 14 is used for press-fitting. In the normal start shaft size, the long plate-like member 20 cannot be brought in. Therefore, by configuring the small piece 20a and connecting and pushing a plurality of small pieces 20a, the same effect as that obtained by inserting and embedding the long plate-like member 20 as a whole can be obtained.

  That is, the small piece 20a which is the plate-like member 20 is first pushed into the hole 13 opened by the wire saw 12 by the jack 14 as shown in FIG. Next, the small piece 20a is pushed in with the jack 14 so that the end face thereof faces the end face of the small piece 20a pushed in first. The plurality of small pieces 20a pushed in with the end faces of the small pieces 20a connected to each other are buried in the ground toward the reaching vertical shaft side. Furthermore, the small piece 20a is pushed in with the jack 14 so that the end surface thereof is opposed to the end surface of the small piece 20a that has been previously inserted. By repeating this, the small piece 20a is embedded. Pushing is stopped in a state where the first small 20a that has been inserted appears on the arrival shaft side. In this way, the plate-like member 20 is embedded as shown in FIG. When burying, carry out along both sides of the construction range of underground structures.

  However, with regard to the embedding of the plate-like member 20, when the construction range of the underground structure is widened, for example, in the case of two lanes or more on one side, the plate-like member as described above. 20 or more may be appropriately set on both side surfaces of the underground structure and its center. Of course, the embedding hole of each plate-like member 20 should just pass a boring hole beforehand and open it with a wire saw after that.

  The embedding in the step of embedding the plate-shaped member in step S300 needs to be embedded at least in two places so that the plate-shaped members 20 are parallel to each other. This is because it is necessary to perform at least two places in order to stop the collapse of the surrounding ground.

  Thereafter, in step S400, as shown in FIG. 9A, the pipe roof 30 is embedded between the embedded plate-like members 20 by the pipe roof construction method. As described above, in the present invention, the step of burying the pipe roof as the auxiliary construction method is characterized in that it is performed in the middle where both plate-like members 20 are embedded. By adopting such a configuration, it is possible to suppress the movement of the surrounding ground that attempts to fill the space due to the surplus excavation during the construction of the pipe roof construction method from the diagonally upper side of the pipe roof 30. FIG. 9B is a cross-sectional view taken along the line AA in FIG.

  As shown in FIG. 9A, the pipe roof 30 is configured by embedding a plurality of pipes 30a formed of steel pipes or the like horizontally. The pipe 30a is first provided with an excavator slightly larger than the diameter of the pipe 30, and is excavated to form a horizontal hole. The pipe 30a having a small diameter is buried in the lateral hole. For this reason, the hole diameter of the horizontal shaft is larger than the pipe diameter, and it is a form that is excessively excavated. Then, it is suppressed by the plate-shaped member 20 embed | buried previously that the surrounding ground is infiltrated into the surplus excavated location.

  In step S500, while excavating the lower part of the pipe roof 30, the cylindrical casing 40a as the crossing skeleton 40 is continuously inserted into the excavation hole. At that time, the guide hole 50 is also excavated as shown in FIG. 10A so that the insertion of the casing 40a is not bent. For such excavation, as shown in FIG. 10 (b), a reaction wall 60 is formed on the wall surface in the start shaft 300. The reaction wall 60 is provided with a jack 61 for promoting the chassis. A casing 40 a is provided on the front end side of the jack 61. A blade edge 70 is provided at the tip of the casing 40 a provided first, and the blade edge 70 is excavated.

  As excavation progresses, the divided casing 40 a is added to the tip end side of the jack 61. By repeating this, a horizontal shaft in which a plurality of casings 40a are connected is formed behind the excavated blade edge 70. Such a state is schematically shown, for example, in FIG. In this way, the crossing skeleton 40 composed of the casing 40a can be provided from the starting vertical shaft 300 to the reaching vertical shaft 400. This state is shown in FIGS. 11 (a) and 11 (b).

  By providing the crossing housing 40, a through hole is formed so as to cross the road 100 and pass through. Thereafter, although not shown, for example, a slope as shown in FIG. 1 may be formed on the start shaft 300 side and the arrival shaft 400 side so that the passage through the through hole can be performed easily. In this way, the underground structure having the plate-like member 20, the pipe roof 30, and the casing 40a is constructed.

  The subsidence suppression effect of the ground surface when constructed by the construction method for underground structures described above was confirmed by numerical analysis. The results are shown in FIG. Further, the numerical analysis model shown in FIG. 13 was used.

  The analysis conditions were two-dimensional finite difference analysis using analysis software manufactured by ITASCA of FLAC (ver 5.0). Here, as shown in FIG. 13, in order to simplify the model, the pipe is only three in the upper half, and the pipe is expressed as A1 → A2 → A3 in order to express the surplus digging in the actual pipe roof. Reproduced by lowering by 5 cm each. In addition, it was judged that the lower half of the pipes A1, A2, and A3 had no influence on the collapse of the ground above the pipe roof, and the model was configured with a semicircle in the upper half.

Analysis cases were performed in the following three cases. In other words, no countermeasure case: only a pipe roof is provided. Chemical solution injection case: When the chemical solution is injected into the illustrated range at 1 m × 1 m. As an effect of the chemical injection, the elastic modulus was estimated to be 1.2 times. Plate member embedded case: When a steel plate having a thickness of 20 mm and a height of 1 m is embedded as a plate member. The elastic modulus of the steel sheet was estimated to be 2100 GPa. As natural ground conditions, as shown in FIG. 13, density γ = 1.5 tf / m ³ , elastic modulus E = 80 MPa, Poisson's ratio γ = 0.3.

  In the analysis results, as shown in FIG. 12, when compared with the maximum subsidence amount, the effect was only 4.06 mm (steel plate), 4.35 mm (no countermeasures / chemical solution injection), and only 0.26 mm. However, for example, if the left side is 50 cm from the construction position of the steel plate (position of 4 m on the horizontal axis in FIG. 12), the sinking amount is 0.98 cm for the steel plate and 2.28 cm for non-measures / chemical injection. It can be seen that the amount of settlement is less than half by installing the steel plate. By embedding and installing the steel plate in this way, for example, the amount of settlement in the range of 4 m on the left and right (4 to 8 m on the horizontal axis in FIG. 12) can be suppressed as compared with the case of the conventional chemical injection method. Since it is lower than the chemical solution injection method, it is confirmed that the embedding installation method of a plate-like member such as a steel plate of the present invention, which is excellent in the settlement suppression effect and can be reduced in cost, is advantageous.

  Incidentally, the allowable subsidence amount is normally set to 5 cm. FIG. 12 shows that the countermeasures, chemical injection, and steel plate embedment all satisfy the above-mentioned criteria for the allowable settlement, but when the cost and the settlement suppression effect are combined, the construction method according to the present invention is advantageous. It can be said that there is.

  Moreover, in FIG. 12, although the amount of settlement on the center side is large, this is because the ground collapse has occurred over the buried steel plate. Therefore, in the case shown in FIG. 12, the height of the steel plate was 1 m, but it can be said that the higher one has a suppressing effect. For example, it can be said that 1.5 m and 1.8 m are more advantageous than 1 m. What is necessary is just to set the height of plate-shaped members, such as a steel plate, suitably based on the local ground actually applied.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention can be effectively applied to the field of crossing structures such as passing-through roads and the like under the roads and tracks of the present invention.

It is a perspective view which shows the construction completion status of the crossing structure under a road and a track. It is a perspective view which shows the construction condition of the crossing structure under a road and a track. (A), (b) is explanatory drawing which shows the positional relationship of the plate-shaped member in a underground structure, a pipe roof, and a crossing construction body, FIG. (C), (d) is an example of embedding a plate-shaped member. It is explanatory drawing which shows the modification of this. (A)-(c) is explanatory drawing which shows the embedding condition of a plate-shaped member. It is explanatory drawing which shows the case of the modification which applied the structure of the underground structure to a connecting mine. It is a flowchart which shows an example of the procedure of the construction method of an underground structure which has an embedding process of a plate-shaped member. (A), (b) is a situation explanatory drawing which shows a mode that a boring hole is opened. (A)-(c) is a situation explanatory drawing which shows the condition which excavates a horizontal shaft with a wire saw and press-fits a plate-shaped member. (A), (b) is a situation explanatory view at the time of constructing a pipe roof. (A), (b) is a situation explanatory drawing in the case of constructing a crossing construction. (A), (b) is a situation explanatory view at the time of installing a crossing construction. It is explanatory drawing which shows the analysis result of ground subsidence at the time of embedding a plate-shaped member. It is explanatory drawing of the analysis model used when carrying out the numerical analysis of the mode of ground subsidence.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Boring hole 11 Boring machine for wire saws 12 Wire saw 13 Hole 14 Jack 20 Plate-like member 20a Small piece 30 Pipe roof 30a Pipe 40 Crossing body 40a Casing 50 Guide hole 60 Reaction wall 70 Cutting edge 100 Road 200 Road 300 Starting vertical Tunnel 400 Reaching shaft 500 Underground structure 510 Casing 510a Top surface 510b Side surface 510c Bottom surface 510d Guide hole 520 Pipe roof 520a Pipe 530 Plate member 530a Small piece

Claims (9)

It is the structure of underground structures such as road / railway crossing structures,
An underground structure characterized in that plate-like members are embedded toward the ground surface side along both side surfaces on the upper surface side of the underground structure that forms a space in the ground. Construction. In the structure of the underground structure according to claim 1,
A structure of the underground structure, wherein a pipe roof is provided between the plate-like members. In the structure of the underground structure according to claim 1 or 2,
The underground structure, or the pipe roof, or the underground structure and the pipe roof, before construction, only the plate-like member is embedded, Construction. In the structure of the underground structure according to any one of claims 1 to 3,
The underground structure is a structure of the underground structure, which traverses a surface-side road such as the existing road / railway. It is a construction method for underground structures such as road / railway crossing structures,
It has a plate-like member embedding step of embedding a plate-like member toward the ground surface side along both side surfaces on the upper surface side of the underground structure that forms a space in the underground to be constructed. Construction method for underground structures. In the construction method of the underground structure according to claim 5,
The said plate-shaped member is embed | buried in the hole in the underground excavated with the wire saw, The construction method of the underground structure characterized by the above-mentioned. In the construction method of the underground structure according to claim 5 or 6,
A construction method for an underground structure comprising a pipe roof burying step of burying a pipe roof after the plate member burying step. In the construction method of the underground structure according to claim 7,
A construction method for an underground structure, wherein the underground structure is constructed after the pipe roof embedding step. In the construction method of the underground structure according to any one of claims 5 to 8,
The construction method of an underground structure, wherein the underground structure traverses below a surface-side traffic road such as the existing road / railway.

Images