JPS6213447B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for excavating a diaphragm wall.

Underground walls are used for a wider range of purposes than before,
Its effectiveness has been evaluated. Specifically, it is used for the foundations of buildings, excavated earth retaining and main body walls, underground tank water stop walls and main body walls, earth retaining of vertical shafts of urban tunnels, etc. The advantages of this construction method are that it can be constructed with low noise and vibration, can be constructed at long depths, has a good water-stopping effect, and can be used on parts of the main structure.

Among the above-mentioned uses, when constructing vertical shafts for urban tunnels, underground continuous walls were often used and the planar shape was rectangular or polygonal. In this case, conventional underground wall excavators have a width of 40 to 80 mm, as shown in Figure 1.
cm, trenches with a length of 2 to 3 m are continuously excavated at once.
This process was repeated to create a rectangular or polygonal shaft.

This underground wall and shaft shape has the following drawbacks. In other words, when excavating inside a shaft surrounded by underground walls, a large number of struts are required as shown in Figure 1, and the working space after completion is narrow, and the length is 2.
Since spans of ~3m are connected, there is a lot of water leakage from the joints, and since the shaft is composed of underground walls with a straight planar shape, the cross section of the underground walls must be made large to resist the surrounding earth pressure. It is necessary, etc.

In order to eliminate the above-mentioned drawbacks, a circular shaft as shown in Figures 2 and 3 was considered, but when constructed using conventional construction methods, there are many joints, so the merits of the circular shaft cannot be fully utilized. In other words, there is a lot of water leakage from the joints, and in order to resist the surrounding earth pressure without struts, the underground wall needs to have a smooth circular shape.In addition, the construction time is long because each span is excavated at a time. It took.

The present invention overcomes the above-mentioned drawbacks.
In other words, by continuously digging in a circular pattern from the ground surface to a predetermined depth, vertical joints can be eliminated and a smooth circular shaft can be completed, eliminating the need for struts inside the shaft. Since the excavation is carried out continuously, construction time is greatly reduced. Figures 4 and 5 are examples of continuous circular underground walls constructed in this manner.

The present invention will be explained below with reference to the drawings.

As shown in FIG.
be installed in advance. Also, place 1 to 2 grooves at the planned location.
The trench is excavated in advance to a depth of m, and guide walls are built on both sides of the trench and filled with muddy water containing an appropriate amount of clay, bentonite, etc., depending on the surrounding groundwater level.

The guide frame 1 on which the cutting device 2 is suspended is connected to the wire 81
While hanging it, lower it until the bit 24 touches the bottom of the groove. The cutting device 2 travels along the guide frame 1 while excavating the ground with the bit 24 by the rotation of a traveling motor 21 installed in the cutting device 2. The excavated earth and sand are transported to the ground together with muddy water by the earth and sand discharge pump 23. A plurality of automatic depth measuring devices are attached to the guide frame 1, and the hoisting electric motor 82 is operated according to the measurement results to move the guide frame 1 up and down. In the example shown in the figure, there are four electric motors 82 for hoisting, corresponding to the number of ruler shafts 3, but the number can be adjusted depending on the scale of the shaft (only one is shown in Fig. 6). ). Moreover, all the installed electric motors 82 for hoisting are arranged to operate in synchronization.

As shown in FIGS. 8, 9 and 10, the guide frame 1 has protrusions 11 and 12 on the upper and lower surfaces, and the cutting device 2
plays the role of guiding. Further, a guide gear 13 that meshes with the gear of the traveling motor 22 is attached to the side surface. Details of the cross section of guide frame 1 are shown in 9th and 1st.
It is shown in Figure 0.

As shown in FIG. 8, the cutting device 2 is equipped with a traveling motor 21, a bit rotation motor 22, and a sand discharge pump 23, and a bit 24 at the bottom.
and a sediment inlet 25 are installed. In the illustrated example, there is one motor for each motor, but a plurality of motors may be provided depending on the scale of the shaft.

As shown in FIG. 9, the rotation of the travel motor 21 is transmitted to the guide gear 13 of the guide frame 1 via the travel gear 211, and the cutting device 2 moves forward or backward. Weight of cutting device 2 or bit 2
The ground reaction force during excavation received by the traveling roller 21
2 to the upper or lower surface of the guide frame 1, making the cutting device run smoothly.

As shown in FIG. 10, the bit rotation motor 2
The rotation of the bit 24 is transmitted to the bit 24 via the bit rotation gear 221, and rotates the bit. Although not shown in the figure, a rotational speed conversion gear may be required. This also applies to the running gear 211.

As shown in FIG. 7, the construction of the underground continuous wall trench is carried out by adjusting the depth of the guide frame 1 using the wire hoisting electric motor 82 according to the procedure described above. The excavated earth and sand is sucked up from the earth and sand suction port 25 and discharged to the ground via the earth and sand discharge pump 23 and the earth and sand discharge pipe 26. Although not shown in the figure, the earth and sand discharge hose 26 and the electric motor cable are suspended from the ground by a crane.

Horizontal swinging of the guide frame 1 during excavation is suppressed by a protrusion 14 that fits into the ruler pile 3 shown in FIG. 6, and excavation can be performed in accordance with the installation accuracy of the ruler pile 3.
Although it is desirable that the installation accuracy of the ruler piles 3 be high, it is possible to excavate a trench for an underground continuous wall even if the installation accuracy of each ruler pile 3 is about 1/100.

When the excavation reaches a required depth, the guide frame 1 and cutting device 2 are pulled up to the ground level by the wire hoisting motor 82 and removed. Thereafter, the underground continuous wall is completed by inserting reinforcing bars and pouring concrete.

According to the method of the present invention, when applied to the construction of a shaft, for example, the shaft is circular, so there is no need for a large number of struts that were previously required, and the work space is widened, making it easier to work inside the shaft. In addition to preventing congestion,
Safety is improved and work time can be shortened. Since the diaphragm wall is constructed without joints, water leakage from the surrounding ground is significantly reduced, and the annular shape provides resistance to surrounding earth pressure and water pressure. The force is large and the concrete cross-section can therefore be reduced, making it economical. In addition, the construction of the underground continuous wall itself can be performed continuously, reducing work time and costs. In addition to the above, the method of the present invention can also be used for foundations of structures, deep foundations for bridge piers, etc., and can also bring about various benefits similar to those described above.

[Brief explanation of the drawing]

Figure 1 is a plan view of a shaft constructed using the conventional construction method, Figure 2 is a plan view of a circular shaft constructed using the conventional construction method, Figure 3 is its elevation view, and Figure 4 is the invention of the present invention. A plan view of a vertical shaft constructed continuously using equipment such as
Figure 5 is an elevation view of the same, Figure 6 is a plan view of the guide frame, cutting device, and ruler pile, and Figure 7 (view from the - arrow in Figure 6) is a diagram explaining the raising and lowering of the guide frame. , a guide frame, a ruler pile, and a wire hoisting electric motor are shown in cross section; Figure 8 is an elevational view of the cutting device and guide frame seen from inside the circular shaft; Figure 9 (in Figure 8, the − arrow Fig. 10 (a view taken along the - arrow in Fig. 8) is a sectional view taken along with the guide frame at the position of the bit rotation motor. In the figure, 1 is a guide frame, 11 is a guide protrusion (upper surface), 12 is a guide protrusion (lower surface), 13 is a guide gear, 14 is a guide part, 2 is a cutting device, 21 is a traveling motor, and 211 is a Travel gear, 212 is a travel roller, 22 is a bit rotation motor, 221
is the bit rotation gear, 23 is the earth and sand discharge pump, 2
4 is a bit, 25 is an earth and sand inlet, 26 is an earth and sand discharge hose, 3 is a ruler pile, 4 is an excavation trench by a conventional device (after concrete is poured), 5 is an excavation trench by the device of the present invention (after concrete is poured), 6 is the ground in the shaft, 5' is the trench excavated by the device of the present invention, 7 is the ground, 81 is the lifting wire, 82 is the lifting motor, 83 is the pulley, 41 is the trundle, 42 is the strut, 43 is flint.

Claims (1)

[Claims] 1. A cutting device 2 equipped with a rotary cutting blade, an earth and sand discharge pump, and a traveling device is suspended on a guide girder 1 having an annular planar shape that can be raised and lowered along a plurality of vertical ruler piles 3. A method for constructing an annular underground wall, comprising constructing an annular underground wall groove while continuously running a device along the annular guide girder.