JPH0376922A - Construction of continuous underground wall and steel panel therefor - Google Patents

Abstract

PURPOSE:To improve efficiency of work execution by a method wherein steel panels of hollow double-walled structure formed of an inner and an outer steel plates and steel ribs are connected with one another, being kept afloat in muddy water with buoyancy given thereto, at their right and left and upper and lower ends, and are sunk with additional connections further made thereto. CONSTITUTION:A steel panel 1 is formed in a double wall structure having hollow space therein, and a box-shaped member 6 is formed therein of an inner steel plate 3, an outer steel plate 4 and a plurality of steel ribs 5 that are provided between the inner and the outer steel plates. The box-shaped member 6 is given buoyancy with lightweight filling agent filled therein or with a hollow part 10 formed therein. The steel panels 1 are then connected with one another by welding or the like applied to each of the ends on the right and the left and on the upper and the lower parts of the steel plate 4, while the panels are kept afloat in muddy water 13 in an excavated ditch. The panels 1 are then sunk with additional panels connected further to the right and the left and to the upper and the lower positions thereof, and a steel double wall body in desired shape is formed therewith as the sinking reaches a specified depth. After this, concrete is cast into a space between the outer periphery of the double wall body and the inner wall of the excavated ditch, or the muddy water in the space is solidified. Thereby a space necessary for execution of work can be made small.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a construction method for a continuous underground wall and a steel panel used as the wall material.

[Conventional Technique fi1] In the conventional general continuous underground wall construction method, the following operations were required for each of the leading and trailing elements. With light hill Lord) 7 top■ Excavation of the preceding element. ■ Installation of interlocking pipes and zigoint vibes. ■ Erection of rebar cage. ■ Placing concrete. 5] Sho 5 ξ Otsu ■ Excavation of the trailing element. ■ Pulling out the tied box. ■ Erection of rebar cage. ■ Placing concrete. [1llfil that the invention aims to solve] Therefore, there were the following problems. (1) When constructing a deep shaft, for example, if the dimensions of the rebar cage are approximately 1 m in width, 6.3 m in length, and 50 m in height, a large crane of 150 t class is required to construct it. Ta. (2) When using a 15Qt class large crane,
A working yard of approximately 100 m x 200 m was required. (3) As a yard for assembling reinforcing bars, it was necessary to secure a yard of approximately 4,500 m, as a raw material storage area, a raw material processing area, a temporary storage area for reinforcing bar cages, etc. were required. (4) ) Because the concrete was poured in muddy water, it was difficult to ensure water-tightness near the horizontal joints. (5) Due to the design, it was necessary to install shoring during excavation. (6) When excavating the shaft, water accumulated on the bottom Drainage equipment was required to treat the water, and the pump had to be moved according to the excavation situation, resulting in poor workability. Problems with boiling and heaving sometimes occurred depending on the situation. (8) Since reinforcing bars were processed and reinforcing bar cages were manufactured at the construction site, it was necessary to gather skilled workers such as reinforcing bar workers at each site. ( 9) Due to reinforced concrete, the wall thickness of the shaft tends to be quite thick due to the design.The present invention enables the construction of continuous walls of great depth efficiently, easily, and with good workability without the above-mentioned problems. [!Means for solving the problem] In the construction method of the present invention, a vertically elongated steel panel is used as a wall material.This steel panel has a hollow double wall structure, In other words, the inner and outer ll14vi and the plurality of rope ribs between them form a box shape, and the inside of the box shape is filled with a lightweight filler or a cavity is formed to give it buoyancy.This f!A!! l While the panels are floating in the muddy water of the excavation trench, the left and right ends and the top and bottom ends of the steel plates of each steel panel are connected by welding, etc., and the steel panels are successively added to the left and right and up and down, allowing them to settle down and form the desired shape. After making a steel double wall in the shape of and sinking it to a predetermined depth, concrete is poured between the outer periphery of the prepared double wall and the inner wall of the excavation trench, or the muddy water in between is solidified and fixed. It is preferable to add steel panels in a staggered manner. After sinking to a specified depth, concrete can also be poured between the steel plates on the outside and inside of the steel panels. If an opening is provided, the concrete placed between the inner and outer steel plates of the steel panel can be further poured from the opening between the outer periphery of the steel double wall and the inner wall of the excavation trench. Joints can be provided on both left and right edges of the steel plates inside and outside the steel panel.

[For production]

W4 panels are manufactured in a factory up to the point where they are filled with lightweight filler, and can be erected as is without any assembly work required on site. Steel panels are given buoyancy by lightweight fillers or hollow sections, so they can be floated in muddy water to reduce weight and can be easily constructed using a small crane. The steel panels can be connected to each other by welding the inner and outer steel plates, making it extremely easy to construct, and also has good water-stopping properties at the joints.The hollow double-wall structure of the steel panel and concrete have synergistic rigidity. The effect also improves structural performance.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a perspective view of an example of a steel panel used in the construction method of the present invention. First, let me explain this steel panel 1. It has a form in which two steel sheet piles and a square steel pipe are integrated. That is, there are two vertically long rope plates (an inner and outer one) each having a U-shaped cross-sectional joint part 2 on the left and right side edges.
A steel sheet pile) 3゜4 and two left and right steel ribs 5 of the same vertical length are integrally molded into a cross-shaped structure, with a box-shaped part (square steel pipe) 6 in the center and recesses 7 on the left and right sides. The box-shaped portion 6 is filled with foamed concrete 8 for reinforcement and buoyancy. The width of the outer steel plate 4 is equal to the width of the inner steel plate 3 so that when the panels 1 made of A are added to the left and right, it becomes cylindrical.
It's bigger. In the steel panel 1 shown in the figure, a large number of openings 9 are provided on both left and right sides of the outer rope plate 4 at predetermined intervals vertically. This opening 9 is for letting the concrete filled in the left and right recesses 7 flow out to the outside, as will be described later. It is not necessary to provide this in all steel panels 1, and it is not necessary to provide this in all steel panels 1. There are also steel panels that are installed only on either the left or right side. Note that the foamed concrete 8 is concrete containing a large number of closed cells, and can be easily made by, for example, creating foam with a foaming agent, kneading the foam with cement straw, and hardening it within the box-shaped portion 6. . When ordinary concrete is used instead of foamed concrete 8, a hollow part 10 is formed in it to give it buoyancy. In addition, although the figure shows an example in which the box-shaped portion 6 is one, FIGS. 8 and 10
As shown in the figure, a plurality of them may be arranged side by side on the left and right. Steel panels 1 of any form are manufactured at a factory and brought to the site with appropriate lengths. FIG. 3 is an explanatory diagram showing the working procedure of an example of the construction method of the present invention;
FIG. 1 is a perspective view showing the process in detail. In FIG. 3, as shown in (a), preliminary excavation for the guide wall described later is performed using a power shovel 11, etc., and as shown in (b) and (C), holes are repeatedly excavated using an excavator 12.
A ring-shaped groove 14 of a predetermined depth filled with muddy water 13 is dug like dl. As shown in (d), with the steel panels 1 suspended by the crane 15, the joints 2 between the steel panels 1 are welded to watertightly connect the steel panels 1 to the left and right, and the bottom cylinder 16. form. And this is crane 1
The steel panels 1 that are adjacent to each other in the circumferential direction are suspended in muddy water 13 while being suspended by 5, and their recesses 7 are continuous to form a vertically elongated cavity. Since a certain steel panel 1 is used in combination with a steel panel L without it or with only one side, a cavity 1 with an opening 9 is created.
7 and a cavity 18 without it are formed. ! ! Only in the lower cylindrical double mesh elmmen 6, the lower end of the cavity 17 without the opening 9 is sealed. Next, as shown in (e), weld the lower end of the second tier steel panel 1 to the upper end of the steel panel 1 of the lowest cylindrical double-shelled Niremen H6+, and then do the same with the crane on the second tier. 15, the steel panel 1 is suspended and connected to the left and right sides at the joint 2, and a second stage cylindrical double-barrel element 16. 16. , 16□
constitutes a double shell 16 which is a continuous cylindrical steel double wall body. In this case, the seams between the upper and lower steel panels 1 should be arranged in a staggered manner to ensure strength, and the cavities 17 with openings 9 and the cavities 18 without them should be vertically continuous, respectively. . Water is poured into the cavity 18 that does not have an opening 9, and the double shell 16 is
is guided by the guide ring 19 (Fig. 1) to the required depth as shown in (f) and allowed to settle. In this state, the third stage (7) circular LJ-shaped double-barrel element 163 is added, and the same operation is carried out thereafter. By repeating the steps (5), the double shell 16 made up of the designed number of cylindrical double shell elements is sunk to a predetermined depth. If the weight of the double shell 16 is such that it will naturally settle into the muddy water 13 due to its own weight, buoyancy may be applied from the outside using an air packer or the like, or it may be supported by the guide ring 19. and keep it floating in the muddy water 13, and perform the replenishment work. Further, for a steel panel provided with a hollow part 10 as shown in FIG. 2, water can be poured into the hollow part 10 to cause it to settle. In this case, the cavity 18 without the opening 9 is not necessarily required. After completing the sinking to the predetermined depth as described above, the opening 9
Water in the cavity 18 where there is no water is drained, and if necessary, concrete 20 is placed in the cavity 18 as shown in FIG. 4 to strengthen the rigidity. Note that 21 is a guide wall. Also, concrete is injected from the tremie pipe 22 into the cavity I7 with the opening 9, and the concrete flows out through the opening 9, and the fifth As shown in the figure, concrete 23 is poured or muddy water therein is solidified to fix the double shell 16 underground. As a result, a continuous underground wall 24 having a double wall structure made of steel and having an overall cylindrical shape is constructed. Next, as shown in FIG. 6, a horizontal poling device 26 for soil improvement and piping 27 to the ground are installed from the spaces (cavities) 25 left at required locations on this continuous underground wall 24, The ground of the bottom bed 28 surrounded by the continuous underground wall 24 is improved. Thereafter, as shown in FIG. 7, the ground surrounded by continuous underground walls 24 is excavated from the ground. In this case, unmanned construction can be performed by attaching a vertical continuous earth removal device (trelifter) 29 and an automatic excavator 30 to the steel inner wall of the continuous underground wall 24. Regarding the treatment of water in the bottom panel 28, a drainage pump 31 is installed in the space 25, and the water is sucked out through a strainer 32 provided on the steel inner wall of the continuous underground wall 24. An elevator 33, stairs, etc. can also be provided on the inner wall. In the above example, after excavating a continuous ring-shaped groove 14, the steel panels 1 connected in a cylindrical shape were sunk into the groove while being successively added to the top, but the groove was not made continuous in a ring-shape from the beginning. Divided into circumferential sections, the prepared panels 1 are deposited in the excavated trenches to a predetermined depth, and then the next trench is excavated and the steel panels 1 are deposited alternately to form a continuous cylindrical shape. There is a way. Figures 8 and 9 are examples of this. After excavating a groove 34 of the required width, the first steel panel h suspended by a crane is inserted into the groove 34, and then submerged in muddy water. Float it and fix it at a required depth using, for example, a guide ring 35, then connect the next second steel panel 1 to the left or right side at the joint 2, and then connect the third steel panel l in the same way. ,
Three steel panels 1 connected in this way
．． ~Work is taken as one element, and the following elements are successively added on top of it. After sinking to a predetermined depth, a mortar jacket 36 is installed near the joint 2 of the steel panels 11.1s on both sides, and the muddy water in the gap 37 surrounded by the mortar jacket 36 is solidified. As a result, one compartment of the prepared double-walled body is destroyed. The shielding tool 38 of the mortar jacket 36 includes a hanging jig 39,
Suspend the muddy water using a hanging row 140 and a crane hook 41 until it solidifies. After the muddy water solidifies, excavate the next adjacent trench, and install steel panels in this trench in the same manner as above.
, ~l, and then add it to the top. In this case, it is connected to the steel double wall of one section that has already been installed at the joint part 2. Thereafter, a continuous cylindrical underground wall is constructed by alternately repeating the excavation of trenches and the connection and addition of prepared panels 1+''-1s. However, the processing of the joint part 2 is different from the examples shown in Figs. To prevent muddy water from solidifying, one section of the steel double-walled body was
After the precept, the muddy water 42 around the entire circumference is solidified. After fixing the steel double wall, as shown in Fig. 11, the steel panels 11 at both ends are fixed.
, 13, using it as a guide, di, S
7. The washer 43 such as a toner cleaner is installed and moved, and the muddy water solidifying material around the joint portion 2 is removed. In addition, if there is a problem when excavating a trench and it is necessary to maintain the excavated part as it is for a long period of time, or if the excavated part is likely to collapse, use a gelling agent that releases the gel state by stirring. It is best to use a so-called chemical gel to turn the muddy water into a gel and stabilize it. The gelled mud water is stirred with an agitator at appropriate times to return it to its original state. In this case, the stirrer can be mounted on a steel double wall. Further, the present invention is widely applicable not only to the horizontal construction of continuous underground walls having a cylindrical shape as a whole, but also to the construction of continuous underground walls of other shapes such as rectangular or elliptical shapes.

【Effect of the invention】

The effects of the present invention are listed below. ■ Hollow double-walled steel panels are used instead of heavy reinforcing cages, which are floated in muddy water and added to the structure. The work can be done even with a crane, allowing efficient construction of continuous underground walls at great depths, and requiring only a small work space. ■ Steel panels can be manufactured in a factory and can be added to as they settle in muddy water, so there is no need for a large work space like that required for on-site assembly of reinforcing cages, and the work space can be saved by 2~ It can be reduced by about 30%. ■ The hollow part of the constructed wall can be used to install drainage equipment and horizontal polling equipment for improving the base. ■ Since the steel panels are manufactured in a factory, the walls can be of uniform quality. ■ Since the joints can be completely welded, complete water-tightness can be ensured as a continuous wall. ■ Manufacturing of steel panels can be done in a separate process from on-site work, so the process at the construction site can be shortened by about half. ■ Lifting equipment such as stairs and elevators can be installed accurately and reliably using the steel inner wall of the continuous underground wall. ■ If there is a wall/frame joint, it can be placed in the specified position. ■ The stress applied to the wall is also transmitted in the circumferential direction of the steel continuous wall, so that the entire structure receives the stress, allowing excavation to be carried out in a short period of time without using struts or uprights.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an example of the construction method of the present invention, Fig. 2 is a perspective view of an example of a steel panel according to the invention, and Figs. Explanatory diagram showing, No. 4
The figure is a cross-sectional view of the state of concrete pouring.
Figure 6 is a plan view showing the state after concrete placement and mud solidification, Figure 6 is a sectional view showing the state of soil improvement of the bottom bed after construction of a continuous underground wall, Figure 7 is a sectional view showing the state of shaft excavation, 8
9 and 9 are a plan view and a sectional view of another example of the construction method of the present invention, and FIGS. 10 and 11 are plan views of still another example. 1...Steel panel, 2...Joint part, 3
．． 4... Inner and outer steel plates, 5... Steel ribs,
6... Box-shaped part, 8... Foamed concrete, 9... Opening, 1o... Hollow part,
13...Muddy water, 14.34...Ditch.

Claims (1)

[Scope of Claims] 1. Buoyancy is achieved by filling the box-shaped interior of a vertically elongated steel panel with inner and outer steel plates and a plurality of steel ribs therebetween, or by forming a cavity. With the steel panels floating in the muddy water of the excavation trench, the left and right ends and the top and bottom ends of the steel plates of each steel panel are connected by welding, etc., and the steel panels are successively added left and right and up and down. After settling the steel double wall to a predetermined depth, concrete is poured between the outer periphery of the steel double wall and the inner wall of the excavation trench. A continuous underground wall construction method characterized by solidifying muddy water. 2. The method for constructing a continuous underground wall according to claim 1, characterized in that the steel panels are submerged while being added in a staggered manner. 3. After making the steel double-walled body and sinking it to a predetermined depth,
3. The method for constructing a continuous underground wall according to claim 1, wherein concrete is placed between the inner and outer steel plates of the steel panel. 4. An opening is provided in the outer steel plate of the steel panel, and concrete is placed between the inner and outer steel plates of the steel panel.
4. The method for constructing a continuous underground wall according to claim 3, further comprising pouring from the opening between the outer periphery of the steel double wall and the inner wall of the excavated trench. 5. Connect two vertically long inner and outer steel plates with a plurality of steel ribs to form a box-shaped part, fill the box-shaped part with a lightweight filler or form a cavity to give it buoyancy, and A steel panel for constructing a continuous underground wall, characterized in that joints are provided on the left and right edges of the inner and outer steel plates, and openings for concrete to flow out are provided in the outer steel plates.