JP5360659B2 - Retaining wall made of precast concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for constructing a retaining wall using precast concrete members, which always and reliably generates the desired vertical support of the wall even with the irregular facing surfaces of an underground trench created in advance. <P>SOLUTION: A cross section of the precast concrete member 1 is formed into an H-shape by slender rectangular flanges parallel to each other and a web 2 integrally provided between the flanges; a bulkhead 5 is integrally provided between both the flanges; window holes 7 opened in a vertically penetrating manner in the web 2 are formed at a desired interval; the width direction of the flange of the precast concrete member 1 is directed in a vertical direction; an earth retaining concrete wall body is formed by making the window holes 7 fixed in such a manner as to correspond to the upper and lower positions between the upper and lower precast concrete members 1; and after the settlement of the concrete wall body to a predetermined depth in the underground trench, a cement-based solidification material is injected under the concrete wall body through the window holes 7 in the upper and lower corresponding positions. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention is a retaining wall for preventing the collapse of the vertical ground surface when excavating the ground surface, for example, to form an underground space, and excavating and forming the retaining wall construction space from the ground surface in advance, The present invention relates to a retaining wall constructed by a precast member in the space.

  In general, as a retaining wall by a precast concrete member when a retaining wall is formed in the ground, and then an underground space is formed with the retaining wall protecting the vertical ground surface, The H-type PC piles are arranged side by side and excavated and pressed into the ground, and a concrete wall is constructed by placing concrete between the flanges of adjacent H-type PC piles. However, there is a structure in which a space is formed by excavating the front side of the retaining wall, and the retaining wall is protected by the retaining wall (for example, Patent Document 1).

  In addition, there is one that has strengthened the integration between sheet piles by inserting a PC tension material in the horizontal direction across the H type PC pile formed by driving in the vertical direction and tensioning it (for example, patent) Reference 2).

  Furthermore, there is a construction in which underground walls are formed by using underground walls by constructing underground walls by placing precast concrete members that are long in the horizontal direction and dropping them into the ground (Patent Document 3).

Japanese Patent No. 3896351 JP 2006-1112045 A Japanese Patent Publication No. 4-32172

  The above-mentioned method of driving the H-shaped precast concrete member upright can use a long member as long as 10 m or more by applying prestress in the vertical direction, and can increase the bending strength.

  However, when there is an obstacle on the ground such as under an elevated road and there is no space for standing a long precast concrete member, there is a problem that the construction is difficult.

  Moreover, in the conventional construction method shown in the above-mentioned Patent Document 3, although a horizontally long precast concrete member is used, it is intended to be used as an underground wall of an underground structure. It is not used as a retaining wall for passages and waterways for intersections and through-passes, and the precast concrete member used is a vertical space where the front and rear wall plates are partitioned by vertical partition walls, and the top and bottom are open The upper and lower precast concrete members are connected to each other by inserting the reinforcing bars into the reinforcing hole embedding them and filling them with mortar. In order to increase the bending strength, it is necessary to increase the thickness of the front and rear wall plates and increase the spacing between the wall plates. There was.

  In addition, in the conventional method in which the precast concrete members are stacked sideways and the concrete wall is settled in the underground groove, the downward load is supported by pressing the lower edge of the lowermost precast concrete member into the bottom of the underground groove. However, since it is difficult to make the depth of the underground trench uniform, it has been difficult to provide a uniform vertical supporting force over the entire retaining wall.

  In view of such conventional problems, the present invention can be easily constructed even when the ground construction space is low and narrow, such as under an elevated road, etc. A large proof strength can be configured with a thinner wall thickness than in the past, and the vertical support force of the retaining wall is even if there is unevenness on the opposite side of the underground trench created in advance, that is, unevenness The object of the present invention is to provide a method for constructing a retaining wall using a precast concrete member that can always obtain a desired desired supporting force.

  In order to solve the conventional problems as described above and achieve the intended purpose, the feature of the invention described in claim 1 is that an underground trench having a width corresponding to the thickness of the retaining wall to be built is excavated and formed. At the opening of the underground groove, a plurality of precast concrete members that are horizontally long are stacked one on top of the other and sequentially connected to form a concrete wall, which is allowed to sink into the underground groove, In the construction method of the retaining wall by the precast concrete member which makes the retaining wall which retained the vertical ground surface by the concrete wall body by excavating the front side, the elongated rectangular flanges parallel to each other as the precast concrete member And a web integrally provided between the flanges to form an H-shaped cross section, and a partition wall is integrally provided between the flanges. Using a shape in which window holes that are vertically opened and opened in the web are formed at a desired interval, the precast concrete member is oriented with the width direction of the flange in the vertical direction, and between the upper and lower precast concrete members. After fixing each other so that the window holes are in positions corresponding to the upper and lower sides, a concrete wall for earth retaining is formed and submerged in the underground groove, and the concrete wall is submerged to a predetermined depth. A concrete wall foundation is formed by injecting a cement-based solidifying material having a supporting function under the concrete wall through the window holes at positions corresponding to the upper and lower sides.

  According to a second aspect of the present invention, in addition to the structure of the first aspect, the formation of the underground trench is achieved by injecting a stabilizing liquid while excavating and stirring the earth and sand of the natural ground into a groove shape from the ground surface. The concrete wall foundation is made by injecting the cement-based solidified material into the mud in the gap between the lower end of the concrete wall and the underground trench and the soft ground at the bottom of the underground trench. It is to create.

  According to a third aspect of the present invention, in addition to the structure of the first or second aspect, the cement-based solidifying material is poured into mud to form a soil cement-like concrete wall foundation. It is to be a cement-based ground improvement material.

  According to a fourth aspect of the present invention, in addition to the structure of any one of the first to third aspects, the concrete wall is a one-unit length concrete wall having a length of the one precast concrete member. Is constructed by connecting the adjacent one-unit-length concrete walls to each other in the horizontal length direction.

  In the present invention, an elongated rectangular flange parallel to each other and a web integrally provided between the flanges form an H-shaped cross section, and a partition is integrally provided between the flanges, and vertically penetrates the web. Using an elongate precast concrete member in which opened window holes are formed at a desired interval, and fixing the precast concrete members to each other so that the window holes are in positions corresponding to each other vertically, A concrete wall is formed in the underground ditch while forming a concrete wall, and after the concrete wall is submerged to a predetermined depth, a cement-based solidifying material is placed under the concrete wall through the window holes at positions corresponding to the upper and lower sides. The bottom of the concrete wall is uneven on the bottom of the underground trench. A being supported by a solidified soil that has been solidified by cement solidifying material is injected into the bottom of the underground trenches.

The longitudinal side view which shows an example of the retaining wall constructed | assembled by the method in this invention. It is the longitudinal section front view. It is a side view of the precast concrete member used for the retaining wall shown in FIG. It is the sectional view on the AA line in FIG. It is a front view of the precast concrete member used for the retaining wall shown in FIG. It is the same top view. It is a longitudinal cross-sectional view which shows the connection state by the PC tendon between the precast concrete members used for the retaining wall shown in FIG. It is a longitudinal cross-sectional view which shows the reinforcement state by the reinforcing bar between the precast concrete members used for the retaining wall shown in FIG. The underground groove | channel formation state in the case of the retaining wall construction in the method of this invention is shown, (a) A vertical side view, (b) is a vertical side view. It is a vertical side view which shows the state which connects and sinks a concrete member in the underground trench same as the above. It is a fragmentary sectional view which shows the creation state of the foundation for concrete walls same as the above.

  Next, embodiments of the present invention will be described based on the examples shown in the drawings. FIG. 1 is a longitudinal side view showing an example of a retaining wall constructed by the method of the present invention, and FIG. 2 is a longitudinal front view thereof. This retaining wall is made of continuous one-unit-length concrete walls A and A that are constructed by connecting a large number of precast concrete members 1 shown in FIGS. And is constructed by building.

  The precast concrete member 1 has a rectangular shape on both edges of a horizontally arranged web 2 having an elongated flat plate shape, and has a H-shaped cross section integrally including a pair of flanges 3 and 3 with the width direction facing up and down. The upper and lower surfaces have groove-shaped recesses 4 and 4 constituted by the flanges 3 and 3 and the web 2. The groove-like recesses 4 and 4 are partitioned by a plurality of partition walls 5, 5... Integrated with both flanges 3 and 3 and the web 2.

  Both ends of the precast concrete member 1 have no web 2 on the front end side of the partition wall 5a closest to the end portion, and have flange extension pieces 3a and 3a projecting only the front end portions of both flanges. Grooves 6 and 6 directed vertically are formed by the pieces 3a and 3a and the partition wall 5a.

  Further, the web 2 is provided with window holes 7, 7... That are vertically positioned at a position between the partition walls 5, 5, or 5 a.

  In the flanges 3 and 3 of the precast concrete member 1, PC tension material insertion holes 10 are formed in the wall thickness at positions intersecting with the partition walls 5 so as to be directed vertically. As shown in FIG. 7, a coupler accommodating diameter increasing portion 11 is formed at the lower end of the PC tendon insertion hole 10, and a support for fixing the PC tendon 12 in a tensioned state at the upper end. A pressure plate 13 is embedded.

  The flange 3 on one side has through-holes 14, 14... For embedding reinforcing bars in the width direction of the flange 3, that is, in the vertical direction, at a predetermined interval. A through opening is provided.

  As shown in FIG. 1 and FIG. 2, the one-unit-length concrete wall A is formed by stacking a plurality of precast concrete members 1, 1... As shown, a PC tension member 12 is used for each of the precast concrete members 1 and 1 adjacent to each other, and they are connected by tensioning them.

  When tensioning, as shown in FIG. 7, the next PC tendon 12 is connected via the coupler 16 to the upper end of the PC tendon 12 fixed in the tensioned state by the fixing bracket 15, and the upper end is connected to the next precast. The operation of fixing on the upper surface of the concrete member 1 in the same manner is repeated to sequentially connect the upper precast concrete member 1 to the lower one.

  Reinforcing bar embedding through holes 14, 14 ... formed in one flange 3 of each precast concrete member 1 are continuous through holes between upper and lower flanges as shown in FIG. A continuous reinforcing bar 20 is inserted in the interior and filled with a cement-type filler 21 such as a high-strength, high-flow mortar.

  The number of the reinforcing bars 20 is designed in anticipation of a bending moment that is generated when the earth pressure on the back surface is applied to the concrete wall A of one unit length. In the flange on the rear surface side of the retaining wall, it is distributed so as to increase in the lower side and decrease in the upward direction, or distributed in the flange on the retaining wall surface side.

  Moreover, as shown in FIG. 2, the one-unit length concrete wall body A which made the length of the precast concrete member 1 a unit has the vertical groove 6 of the both ends of each precast concrete member 1 on the both sides. Are arranged in a continuous arrangement in the top and bottom, and a concave groove is formed on both side surfaces of the one unit length concrete wall A so as to extend vertically, and the adjacent one unit length concrete walls A and A are abutted together. A hollow cylinder portion 24 is formed in the upper and lower portions by both concave grooves 6 and 6, and a cement system such as soil cement or cast-in-place concrete in a place where cement milk is mixed with mud in the inside. A solidified column 25 is formed on the cast-in place solidified by the solidifying material. The solidified column 25 connects the concrete walls A, A by one unit length.

  The unit-length concrete wall A is connected to the web 2 of each precast concrete member 1 so that the window holes 7 are in positions corresponding to the upper and lower sides, and forms a continuous opening from the upper end to the lower end of the wall. Yes. A cement-based solidifying material injection pipe is inserted into the opening from the upper end to the lower end, and the cement-based solidifying material is injected from the lower end into the vicinity of the ground where the lower end of the wall A is in contact with the concrete wall. A base 26 is formed. Thus, the function of supporting the vertical force acting on the wall body A is provided.

  In constructing the retaining wall described above, first, as shown in FIGS. 9 (a) and 9 (b), the underground groove having a width, depth and length in which the concrete wall A can be formed in the ground by one unit length from the ground surface. 30 is excavated. This underground trench is formed by using a drilling stirrer 33 to which a pair of cutters 31 are attached at the lower end and a jet nozzle 32 for jetting water downward from the middle is used. A method of forming the underground trench 30 filled with the mud 34 by mixing the water with water can be used. In addition, a method may be used in which the underground groove 30 is formed using a backhoe or a grab bucket for trench excavation and the excavated trench is filled with a stabilizing liquid.

  Next, as shown in FIG. 10, the precast concrete members 1 and 1 adjacent to each other in the vertical direction are connected vertically in the underground groove 30, and the height of the precast concrete member 1 is completed every time one connection is completed. It sinks in the underground groove 30 for every minute (flange width). At this time, the mud 34 in the underground groove 30 moves to the upper side of the web from the window hole 7 of the precast concrete member 1, and is therefore settled by the weight of the precast concrete member 1 or a press-fitting device.

  In addition, the portal crane installed across the underground ditch | groove 30 can be used for carrying in and sedimentation of this precast concrete member 1 as an example.

  After assembling the one unit length concrete wall body A in the underground groove 30, as shown in FIG. 11, the window holes 7, 7. ...... Cement-based solidifying material injection pipe 35 is inserted to the bottom of the wall body from the upper end opening of the cement-based cement mud between the bottom surface of the underground groove 30 and the lowermost precast concrete member 1. Solidified material is injected. At this time, the lowermost window holes can be arranged more than the lowermost window holes so that the injection is easy. As a result, the soft ground at the bottom of the underground ditch 30 and the mud 34 between the bottom of the underground ditch and the end of the concrete wall A are solidified to form the concrete wall foundation 26. As the cement-based solidifying material, a ground improvement material for soft ground such as cement milk can be used.

  In addition, when the underground groove is filled with a stabilizing liquid, the concrete wall foundation 26 may be formed by filling cement mortar or concrete.

  After constructing the concrete wall A of one unit length in this way, another one unit length of the concrete wall A is formed in the same manner by continuing in the horizontal length direction. As a result, a square cylindrical space formed by the concave grooves 6 and 6 is formed on the opposite side edges of both the unit length concrete walls A and A, and the cement-based solidified material is put in the mud inside. The column body 25 is formed by injecting and solidifying the mud in the space, and the adjacent one-unit-length concrete walls A and A are connected.

  The column 25 is made of cement-based solidified material, a dedicated earth removing device is used to remove the mud 34 in the square cylindrical space, and a concrete casting device such as a tremy pipe is used to cast in place. The column body 25 may be formed by placing concrete.

  In this way, one unit length concrete wall A, A is constructed to be continuous to the required length, and then the vertical ground is excavated on the front side of the ground to create a one unit length concrete wall body. A desired underground space that is retained by A is formed.

  After the formation of the underground space, the concrete wall A having a length of one unit may be prevented from falling by an underground anchor as shown in FIG. In this case, the underground anchor has an anchor insertion hole 50 formed in advance at a portion where the web 2 and the partition wall 5 of the precast concrete member 1 intersect, and a steel rod, a steel strand, or the like is formed in the anchor insertion hole 50. The tension member 51 is inserted, the tip is embedded in the anchor concrete 52 in the soil and fixed in the soil, and the other end is tension-fixed on the surface side of the precast concrete member 1.

  Thus, by forming the anchor insertion hole 50 at the portion where the web 2 and the partition wall 5 intersect and fixing at the crossing position, the stress at the fixing portion is effectively dispersed vertically and horizontally, and the proof stress A large retaining wall.

  The fixing plate used for anchoring the anchor is embedded in the concrete wall or installed later.

A One-unit-length concrete wall 1 Precast concrete member 2 Web 3 Flange 3a Flange tip 4 Groove recess 5 Partition 5a End partition 6 Groove 7 Window hole 10 PC tension material insertion hole 11 Enlargement for accommodating coupler Diameter portion 12 PC tension member 13 Bearing plate 14 Reinforcing bar embedding through hole 15 Fixing bracket 16 Coupler 20 Reinforcing bar 21 Cement filler 23 Top plate 24 Hollow tube part 25 Column body 26 Concrete wall base 30 Underground groove 31 Cutter 32 Jet nozzle 33 Excavator Stirrer 34 Mud 35 Cement-Based Solidifying Material Injection Pipe 50 Anchor Insertion Hole 51 Tensile Material 52 Anchor Concrete

Claims (4)

A concrete wall is formed by excavating and forming an underground groove having a width corresponding to the thickness of the retaining wall to be constructed, and sequentially connecting a plurality of precast concrete members that are horizontally long in the horizontal direction so as to overlap each other. Forming a body, sinking it into the underground ditch, and excavating the front side of the concrete wall to hold the vertical ground surface by the concrete wall as a retaining wall. In the wall construction method,
As the precast concrete member, an elongated rectangular flange parallel to each other and a web integrally provided between the flanges form an H-shaped cross section, and a bulkhead is integrally provided between the flanges, and the web is vertically arranged on the web. Use a shape that has a window hole that is opened through at a desired interval,
By fixing the precast concrete members to each other so that the width direction of the flange is directed in the vertical direction and the window holes are positioned between the upper and lower precast concrete members, the concrete walls for earth retaining This is allowed to sink into the underground trench while forming
After sinking the concrete wall to a predetermined depth, a cement-based solidifying material having a supporting function is injected under the concrete wall through the window holes at positions corresponding to the upper and lower sides, thereby forming a foundation for the concrete wall. A method for constructing a retaining wall using a precast concrete member.   The formation of the underground ditch is a state where mud soil is filled in the ditch by injecting a stabilizing liquid while excavating and stirring the earth and sand of the natural mountain in the shape of a ditch from the ground surface, and the cement-based solidified material is placed on the concrete wall. The method for constructing a retaining wall using a precast concrete member according to claim 1, wherein the foundation for the concrete wall body is formed by pouring the mud in the gap between the lower end and the underground groove and the soft ground at the bottom of the underground groove.   3. The cement-based ground improvement material according to claim 1 or 2, wherein the cement-based solidifying material is a cement-based ground improvement material in which a soil cement-like foundation for a concrete wall body is formed by pouring into mud. Construction method.   The concrete wall is formed by continuously forming one unit-length concrete wall of the length of the one precast concrete member in the horizontal length direction and connecting the adjacent one-unit length concrete walls to each other. The construction method of the retaining wall by the precast concrete member of Claim 1 constructed | assembled by doing.

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