JP6527379B2 - Earth fixing method - Google Patents

Description

  The present invention relates to an earth retaining method.

  Conventionally, when constructing an underground structure, an open-cut method using earth retaining walls is generally used. FIG. 5 is a diagram showing an outline of the open-cut method. As shown in FIG. 5, in the open-cut construction method, after the earth retaining wall 103 is formed on the ground 101, the support work 105 is installed as necessary, and the ground 101 on the excavation side 107 is excavated.

  In the case of an open-cut method as shown in FIG. 5, when a structure is present in the influence range of the back of the digging in an urban area or the like, it is necessary to suppress the deformation of the retaining wall (for example, about 1.0 cm). However, when a general steel sheet pile is used as the earth retaining wall 103, even if the digging depth is relatively shallow (for example, about 3 m), the deformation of the self-supporting earth retaining wall becomes large. Therefore, the support work 105 is required to suppress the deformation.

  FIG. 6 is a diagram showing an example of calculation of stress and displacement of a retaining wall. In Fig. 6, the earth retaining wall is installed when using a steel sheet pile to install the earth retaining wall on a sandy soil with a groundwater level of GL-2.0 m and a shear resistance angle of% = 30%, and digging under various conditions The calculation example of stress and displacement amount of

  Fig.6 (a) is a figure which shows the example which is excavated so that the steel sheet pile stress of a self-supporting earth retaining wall may become the largest. If steel sheet pile stress of the free standing earth retaining wall is generated to the allowable stress level, as shown in Fig. 6 (a), it is possible to excavate to a depth of 3.5 m, but the displacement of the earth retaining wall becomes about 36 cm, The influence on the back ground of the retaining wall is large.

  Drawing 6 (b) is a figure showing an example drilled so that displacement of a self-supporting earth retaining wall may be less than 1.0 cm. Assuming that the displacement is 1.0 cm in consideration of the influence of the earth retaining wall on the back ground, the excavation depth is about 1.65 m, as shown in FIG. 6 (b). Further, the stress of the steel sheet pile is about 1/12 of the allowable stress degree.

  FIG.6 (c) is a figure which shows the example which installs one step of supports and excavates so that the displacement of a retaining wall may be less than 1.0 cm. Assuming that one support is installed and the displacement is 1.0 cm in consideration of the influence of the earth retaining wall on the back ground, as shown in FIG. 6C, the digging depth is about 3.1 m. In addition, the stress of the steel sheet pile is about 1/7 of the allowable stress.

  FIG. 6 (d) is a diagram showing an example in which the displacement of the earth retaining wall is within 1.0 cm and drilling is performed to a depth of 3.5 m. In order to excavate to a depth of 3.5 m while making the displacement 1.0 cm in consideration of the influence of the earth retaining wall on the back ground, it is necessary to install two stages of supports as shown in Fig. 6 (d) . The stress of the steel sheet pile is about 1/8 of the allowable stress.

  As shown in FIGS. 6 (c) and 6 (d), when the support is installed, it is possible to dig deeply while suppressing the displacement of the earth retaining wall. On the other hand, there is a problem of the restriction of the shape of the underground structure and the deterioration of the workability by arranging the support. In addition, the stress of the steel sheet pile of the retaining wall is only about a few percent of the allowable stress degree, which is wasteful.

  Therefore, a method has been proposed for securing the drilling depth without installing a support. FIG. 7 is a view showing an example using the steel sheet pile 111 whose bending rigidity is enhanced. FIG. 7A shows a perspective view of the steel sheet pile 111, and FIG. 7B shows an example of excavating the ground 109 using the steel sheet pile 111 as a retaining wall.

  As shown in FIG. 7A, in the steel sheet pile 111, the tendon 113 is disposed in the longitudinal direction. An anchor fitting 115 is provided at the end of the tendon 113. In the excavation work, the steel sheet pile 111 in a state in which the tendon 113 is tensioned to an extent not loosening is drilled on the ground 109 for excavation. And as shown in FIG.7 (b), when a deformation | transformation of the steel sheet pile 111 becomes large with advancing of digging, the screw processed into the anchor metal fitting 115 is further tightened, and bigger tension | tensile_strength is further tensed to the tension member 113 A force is applied to suppress the deformation of the steel sheet pile 111 (see, for example, Patent Document 1).

  In addition, in road construction and the like, in order to reduce cutting on slopes, a method of installing a plastically deformed earth retaining member in the ground and excavating the inside has been proposed (for example, see Patent Document 2) ).

Japanese Patent Application Laid-Open No. 11-50446 JP-A-11-229377

  However, the method of providing the earth retaining member with a tendon and introducing tension after excavation complicates the apparatus. Moreover, also when excavating using the plastic deformation earth retaining member, deformation of the earth retaining member by back earth pressure arises.

  The present invention has been made in view of the above-mentioned problems, and the purpose thereof is to effectively suppress the deformation of the earth retaining member by effectively generating and utilizing the elastic force of the earth retaining member itself. It is to provide a fastening method.

The first invention for achieving the above-mentioned object comprises a step a of press-fitting the ground retaining member into the ground while elastically deforming the earth retaining member to construct a earth retaining wall, and a ground of the earth retaining side of the earth retaining wall Excavating step b, and after the step b, by the elastic force generated by the elastic deformation of the earth retaining member, the deformation of the earth retaining wall to the excavating side due to the earth pressure of the ground on the back side is suppressed The earth retaining member is a member bent in advance so that the back surface side is concave, and in the step a, the earth retaining member is pressed into the ground while correcting the bending .
In the second invention, a step a of pressing the ground retaining member into the ground while elastically deforming the ground retaining member to construct a retaining wall, and a step b of digging the ground on the excavating side of the retaining wall,
After the step b, by the elastic force generated by the elastic deformation of the earth retaining member, the deformation of the earth retaining wall to the digging side due to the earth pressure of the ground on the back side is suppressed.
The earth retaining member is a member which is plastically deformed in advance so that the back side is concave, and in the step a, the earth retaining member is pressed into the ground while correcting a bend .

According to the first and second inventions, the earth retaining member is pressed into the ground while being elastically deformed, and the elastic force of the earth retaining member itself is effectively generated and utilized at the time of excavation. Deformation can be suppressed.

Also, in any case, the elastic force is generated effectively by elastically deforming the earth retaining member in the process of correcting the bending of the earth retaining member, and the elastic force is used to generate the earth retaining force. The deformation of the wall to the digging side can be suppressed.

In the step a, the earth retaining member may be elastically deformed to the digging side by press-fitting the earth retaining member into the ground through a bending correction mechanism.
By means of the bending correction mechanism, the earth retaining member can be elastically deformed to the digging side with high accuracy.

In the first and second inventions, a guide earth retaining member installed in advance in the ground is used, and in the step a, while the connection part of the earth retaining member is connected to the connection part of the guide earth retaining member It is desirable to elastically deform the earth retaining member to the excavating side by pressing the earth retaining member into the ground.
Further, as a third invention, a step a of pressing the ground retaining member into the ground while being elastically deformed to the digging side to construct a retaining wall, and a step b of digging the ground on the digging side of the retaining wall; After the step b, by the elastic force generated by the elastic deformation of the earth retaining member, the deformation of the earth retaining wall to the excavating side due to the earth pressure of the ground on the back side is suppressed, In the step a, using the guide earth retaining member installed, the earth retaining member is pressed into the ground while connecting the connection part of the earth retaining member to the connection part of the guide earth retaining member. The earth retaining method may be characterized in that the fastening member is elastically deformed to the digging side.
In this way, the earth retaining member is press-fit into the ground while the earth retaining member is connected to the connection portion of the guide earth retaining member while the connection portion of the earth retaining member is connected, whereby the earth retaining member is elastically deformed and pressed into the ground Work is easier.

In the first to third inventions, at the step b, a support may be installed on the digging side of the earth retaining wall in accordance with the digging depth of the ground.
In the first to third inventions, by suppressing the deformation of the earth retaining wall utilizing the elastic force of the earth retaining member itself, the number of installed supports is reduced compared to the case where the elastic force is not utilized. be able to.

  According to the present invention, it is possible to provide the earth retaining method capable of suppressing the deformation of the earth retaining member by effectively generating and utilizing the elastic force of the earth retaining member itself.

Diagram showing earth retaining members used to construct earth retaining walls The figure which shows the earth retaining method using earth retaining wall 17 The figure which shows the example of calculation of various values in the step which constructed the retaining wall 2 in the ground 19, and excavated the excavation side 25 Figure showing an example using a bend correction mechanism Diagram showing the outline of the open-cut method Diagram showing calculation example of stress and displacement of retaining wall The figure which shows the example using the steel sheet pile 111 which raised bending rigidity.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a figure which shows the earth retaining member used for construction of an earth retaining wall. FIG. 1A is a plan view of the guide earth retaining member 1, and FIG. 1B is a side view of the guide earth retaining member 1. FIG. 1 (c) is a plan view of the earth retaining member 3a, and FIG. 1 (d) is a side view of the earth retaining member 3a. FIG. 1 (e) is a plan view of the earth retaining member 3b, and FIG. 1 (f) is a side view of the earth retaining member 3b.

  As shown in FIGS. 1 (a) and 1 (b), the guide earth retaining member 1 is a generally straight U-shaped steel sheet pile. The guide earth fastener 1 has a connection 5 along the flange.

  As shown in FIGS. 1 (c) and 1 (d), the earth retaining member 3a is a U-shaped steel sheet pile. The earth retaining member 3a is a member molded as a member bent in advance so that the outer side 9a of the web is concave. Alternatively, a substantially straight normal U-shaped steel sheet pile may be a member plastically deformed in advance so that the outer side 9a of the web is concave. The earth retaining member 3a has a connecting portion 7a along the flange.

  As shown in FIG. 1 (e) and FIG. 1 (f), the earth retaining member 3b is a U-shaped steel sheet pile. The earth retaining member 3b is a member pre-bent such that the inner side 11b of the web is concave, or a member obtained by plastically deforming a generally straight U-shaped steel sheet pile so that the inner side 11b of the web becomes concave. Do. The earth retaining member 3b has a connecting portion 7b along the flange.

  FIG. 2 is a view showing a method of earth retaining using the earth retaining wall 17. FIG. 2A is a horizontal sectional view of the retaining wall 17. FIG. 2 (b) is a view showing a press-fitting method of the earth retaining member 3. FIG. 2C is a view showing a state before excavation of the ground 19 on which the earth retaining wall 17 is installed, and FIG. 2D is a view showing a state after excavation of the ground 19 on which the earth retaining wall 17 is installed is there.

  As shown in FIG. 2A, the earth retaining wall 17 is composed of a guide earth retaining member 1 and a plurality of earth retaining members 3. In order to construct the earth retaining wall 17, first, the guide earth retaining member 1 is pressed into the ground 19 so that the inner side 15 is the back side 23 and the outer side 13 is the excavation side 25. Then, while connecting the connection portion 7a of the earth retaining member 3a to the connection portion 5 of the guide earth retaining member 1, the earth retaining member 3a is ground 19 so that the outer side 9a is the back side 23 and the inner side 11a is the excavating side 25. Press fit into

  Next, while connecting the connection portion 7b of the earth retaining member 3b to the connection portion 7a of the earth retaining member 3a, the earth retaining member 3b is ground 19 so that the inner side 11b is the back side 23 and the outer side 9b is the digging side 25. Press fit into Thereafter, the earth retaining members 3a and the earth retaining members 3b are alternately press-fit into the ground 19 while connecting the connecting portion 7a and the connecting portion 7b. As shown in FIG. 2 (b), a press-in machine 21 is used for press-fitting the guide earth retaining member 1 and the earth retaining member 3 into the ground 19.

  After press-fitting the guide earth retaining member 1, the earth retaining member 3a is bent such that the back side 23 is concave by connecting the connecting portion 7a of the earth retaining member 3a to the connecting portion 5 of the guide earth retaining member 1. Is pressed into the ground 19 while being elastically deformed so as to substantially straighten. Even after that, by connecting the connecting portions 7 of each earth retaining member 3 to the connecting portions 7 of the adjacent earth retaining members 3 which are press-fitted in advance, each earth retaining member 3 has a concave back surface 23 It is pressed into the ground 19 while being elastically deformed so as to substantially straighten the bending.

  By pressing each earth retaining member 3 into the ground 19 while elastically deforming as described above, a substantially vertical earth retaining wall 17 is constructed in the ground 19. The guide earth retaining member 1 may be removed before excavation of the ground 19. After completion of the earth retaining wall 17, as shown in FIG. 2 (d), the ground 19 on the excavation side 25 of the earth retaining wall 17 is excavated to a predetermined depth.

  In the example shown in FIG. 2A, a substantially straight U-shaped steel sheet pile is used as the guide earth retaining member 1, but the guide earth retaining member may be substantially straight when pressed into the ground 19. That is, the earth retaining member 3 shown in FIG. 1 installed in the ground while being elastically deformed in advance may be used as a guide earth retaining member. If it is approximately straight when installed in the ground in advance, it can exhibit the same function and function as a substantially straight U-shaped steel sheet pile or the like. Therefore, when press-fitting the earth retaining member 3b, the earth retaining member 3a serves as a guide earth retaining member.

  As shown in FIG. 2C, in a state where the ground 19 on the digging side 25 of the retaining wall 17 is not excavated, elastic deformation of the retaining member 3 from the retaining wall 17 to the ground 19 on the back side 23 By the elastic force generated by this, a force as shown by arrow A is applied. Further, the earth pressure of the ground 19 on the back side 23 is in a passive earth pressure state as shown by the arrow B.

  As shown in FIG. 2 (d), in a state where the ground 19 on the digging side 25 of the retaining wall 17 is excavated, it is generated by elastic deformation of the retaining member 3 from the retaining wall 17 on the ground 19 on the back side 23 The elastic force shown in FIG. In addition, the earth pressure of the ground 19 on the back side 23 is in the state of the dynamic earth pressure as shown by the arrow C. When the force in the direction indicated by the arrow A applied from the earth retaining member 3 is larger than the component in the direction indicated by the arrow D of the dynamic earth pressure of the ground 19, the earth retaining wall 17 does not deform to the digging side 25.

  Below, the determination method of the bending condition of earth retaining member 3a and earth retaining member 3b is described. The degree of bending of the earth retaining member 3 is determined in consideration of the predicted displacement of the earth retaining member in the case of construction using a normal earth retaining member, according to the nature of the ground to be cut and the excavating depth.

  For example, as shown in FIG. 2, when the earth retaining wall 17 is constructed on the ground 19 and the excavation side 25 is excavated to a depth of 3.5 m, as shown in FIG. In consideration of the displacement of the retaining wall 2 when the retaining wall 2 is constructed using the above method and the excavation side 25 is excavated to a depth of 3.5 m, the bending condition of the retaining member 3a and the retaining member 3b is determined Do.

  FIG. 3: is a figure which shows the example of calculation of the various values in the step which constructed the earth retaining wall 2 in the ground 19, and excavated the excavation side 25. As shown in FIG. The ground 19 is a sandy soil having a groundwater level of GL-2.0 m and a shear resistance angle of == 30%. In FIG. 3, a normal U-shaped steel sheet pile is placed on the ground 19 to construct the retaining wall 2, and the effective earth pressure of the ground 19 is effective when the ground 19 on the excavation side 25 is excavated to a depth of 3.5 m. Water pressure, showing a ground spring. In addition, the amount of displacement of the retaining wall 2 and the bending moment when the effective side pressure is applied to the retaining wall 2 by determining the effective main pressure and the effective passive pressure from the earth pressure and water pressure according to the standards of various academic societies etc. , Show the shear force.

  As shown in FIG. 2, when the earth retaining wall 17 is constructed on the ground 19 and the excavating side 25 is excavated to a depth of 3.5 m, the earth retaining member 3a constituting the earth retaining wall 17 is the back side 23 of the ground 19 Shape of the displacement amount graph shown in FIG. 3 such that the earth retaining member 3b is concave on the back side 23 of the ground 19 so that the outer side 9a of the web is concave. It is desirable to The shape of the earth retaining member 3 is such that the force in the direction shown by the arrow A applied from the earth retaining wall 17 shown in FIG. 2D is larger than the component in the direction shown by the arrow D of the driving earth pressure of the ground 19 Any shape is acceptable.

  As described above, according to the present embodiment, the earth retaining member 3 which is a member bent or plastically deformed in advance so that the surface which becomes the back surface side 23 becomes concave when pressed into the ground 19 is bent. By using the elastic force of the earth retaining member 3 itself when pressing in the ground 19 while making elastic deformation so as to correct and excavating the ground 19 on the excavation side 25, the earth retaining wall by earth pressure from the back side 23 17 deformation can be suppressed.

  Further, when constructing the earth retaining wall 17, bending of the earth retaining member 3a is performed by press-fitting the earth retaining member 3a which is followed by using the guide earth retaining member 1 press-fit into the ground 19 as a guide. It can be easily corrected. Furthermore, the bending of the earth retaining member 3 to be followed can be easily corrected by press-fitting the earth fixing member 3 to be followed using the earth retaining member 3 pressed in while correcting the bending in advance.

  In the present embodiment, an example in which the support is not used is described, but the earth retaining member constructed by pressing in the ground while elastically deforming the earth retaining member is combined with the support and earth retaining is performed. It is also good. For example, when excavating using the earth retaining wall and the support work under the conditions shown in FIG. 6 (c), using the earth retaining member in a shape obtained by reversing the graph of the displacement amount shown in FIG. 6 (c) At the time of excavation of the ground, the deformation of the retaining wall can be suppressed. In the case of combined use of earth retaining wall and support, the installation depth of support is, for example, dig 5m and install support at 4.5m, dig further up to 10m and support at 9.5m Set according to the cutting depth of the ground, such as installing.

  In the present embodiment, as shown in FIG. 1, the earth retaining member having a shape bent only at the upper end is used, but the shape of the earth retaining member is not limited to this. The shape of the earth retaining member is determined according to the nature of the ground and the excavating depth, and the force applied to the ground on the back side from the earth retaining wall formed by press-fitting the earth retaining member while correcting the bend excavates the ground Sometimes it should be larger than the horizontal component of the earth pressure applied to the earth retaining wall from the ground on the back side. The earth retaining member is not limited to the U-shaped steel sheet pile, but may be a steel sheet pile using round steel or H steel.

  In the present embodiment, the substantially earthed guide earth retaining member 1 is used to elastically deform the earth retaining member 3 so that the earth anchoring member 3 is corrected substantially straight. However, the shape of the guide earth retaining member is not limited to substantially straight. The bending of the guide earth retaining member may be any bending different from that of the earth retaining member, as long as it can be guided while being elastically deformed into a desired shape. Further, when constructing the earth retaining wall, the guide earth retaining members may be arranged every predetermined number.

  Further, if the earth retaining members 3a and 3b can be pressed into the ground 19 while being elastically deformed on the ground, the guide earth retaining member 1 is not necessarily required.

  In this embodiment, as shown in FIG. 2 (b), the earth retaining member 3 and the like are press-fit into the ground 19 using the press-in machine 21, but the earth retaining member 3 and the like are made using the press-in machine and the bending correction mechanism. It is also possible to press fit into the ground 19. FIG. 4 is a view showing an example using a bending correction mechanism.

  FIG. 4A shows an example in which the bending correction mechanism 27 is disposed below the press-fitting machine 21a. FIG.4 (b) and FIG.4 (c) are sectional drawings by arrow EE shown to Fig.4 (a). In the example shown in FIG. 4A, the earth retaining member 3 is pressed into the ground 19 while being elastically deformed on the digging side 25 via a bending correction mechanism 27 disposed below the press-fitting machine 21a.

  The cross section of the bending correction mechanism 27 has two types of patterns shown in FIG. When pressing the earth retaining member 3a shown in FIG. 1 into the ground 19 as shown in FIG. 4B, it is a bend in which through holes 29a having a shape corresponding to the earth retaining member 3a are formed straight in the vertical direction. The correction mechanism 27a is used. When pressing the earth retaining member 3b shown in FIG. 1 into the ground 19 as shown in FIG. 4C, it is a bend in which through holes 29b having a shape corresponding to the earth retaining member 3b are formed straight in the vertical direction. The correction mechanism 27b is used.

  In the example shown in FIGS. 4 (a), 4 (b) and 4 (c), the earth retaining member 3 shown in FIG. 1 is passed through the press-in machine 21a and the bending correction mechanism 27 and provided vertically straight. The earth retaining member 3 is pressed into the ground 19 by the press-in machine 21 a while elastically deforming the earth retaining member 3 to the digging side 25 by the through holes 29.

  FIG. 4 (d) shows an example in which the bending correction mechanism 31 is disposed below the press-fitting machine 21b. The bending correction mechanism 31 has a hydraulic jack 33 in the upper half that pushes the earth retaining member 3 to the digging side 25 and a hydraulic jack 33 that pushes on the back side 23 in the lower half. In the example shown in FIG. 4D, the earth retaining member 3 shown in FIG. 1 is passed through the press-in machine 21b and the bending correction mechanism 31, and the hydraulic jack 33 of the bending correction mechanism 31 is controlled to dig the earth retaining member 3 The earth retaining member 3 is pressed into the ground 19 by the press-in machine 21b while being elastically deformed.

DESCRIPTION OF SYMBOLS 1 ...... Guide earth retaining member 2, 17 ...... Earth retaining wall 3, 3a, 3b ...... ...... Earth retaining member 5, 7, 7a, 7b ......... connection part 9, 9a, 9b, 15 ............ Inside 11, 11a, 11b, 13 ...... Outside 19 ...... Ground 21, 21a, 21b ...... Press-in machine 23 ...... Back side 25 ...... Excavating side 27, 31 ...... Curve correction mechanism

Claims (6)

A step a of press-fitting the ground retaining member into the ground while elastically deforming the digging side to construct a retaining wall a,
A step b of excavating the ground on the excavation side of the retaining wall;
Equipped with
After the step b, the elastic force generated by the elastic deformation of the earth retaining member suppresses the deformation of the earth retaining wall to the digging side due to the earth pressure of the ground on the back side ,
The earth retaining member is a member bent in advance so that the back side is concave, and in the step a, the earth retaining member is pressed into the ground while correcting the bending . A step a of press-fitting the ground retaining member into the ground while elastically deforming the digging side to construct a retaining wall a,
A step b of excavating the ground on the excavation side of the retaining wall;
Equipped with
After the step b, the elastic force generated by the elastic deformation of the earth retaining member suppresses the deformation of the earth retaining wall to the digging side due to the earth pressure of the ground on the back side ,
The earth retaining member is a member which is plastically deformed in advance so that the back surface side becomes concave, and in the step a, the earth retaining member is pressed into the ground while correcting a bend . Wherein in step a, by press-fitting to the ground via the correcting mechanism bends the soil retaining member, as claimed in claim 1 or claim 2, characterized in that to elastically deform the excavation side the soil retaining member Earth fixing method. Using a guide earth retaining member previously installed in the ground,
In the step a, the earth retaining member is elastically deformed to the digging side by pressing the earth retaining member into the ground while connecting the connection portion of the earth retaining member to the connection portion of the guide earth retaining member. The earth retaining method according to any one of claims 1 to 3 , characterized by A step a of press-fitting the ground retaining member into the ground while elastically deforming the digging side to construct a retaining wall a,
A step b of excavating the ground on the excavation side of the retaining wall;
Equipped with
After the step b, the elastic force generated by the elastic deformation of the earth retaining member suppresses the deformation of the earth retaining wall to the digging side due to the earth pressure of the ground on the back side ,
Using a guide earth retaining member previously installed in the ground,
In the step a, the earth retaining member is elastically deformed to the digging side by pressing the earth retaining member into the ground while connecting the connection portion of the earth retaining member to the connection portion of the guide earth retaining member. Earth retention method characterized by   The earth retaining method according to any one of claims 1 to 5, wherein a support is installed on the excavation side of the earth retaining wall according to the depth of the excavation of the ground in the step b.

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