JPH04115024A - Sheathing method - Google Patents

Abstract

PURPOSE:To build a sheathing wall without bracing even on a soft soil foundation by arranging foundation anchors between the wall and a foundation improving part outside of the wall so that the forward ends of the foundation anchors are fixed to the foundation improving part. CONSTITUTION:The bottom base inside of a sheathing wall 1 is subjected to foundation improvement 2 over the entire area thereof, and suitable places on the earth side are also subjected to foundation improvement 3. Foundation anchors 4 are stretched between the wall 1 and the foundation improving part 3 on the outside of the wall 1 so that their front ends are fixed to the foundation improving part 3. Since the front end part of the anchors 4 are present on the foundation improving part 3, the anchors 4 cannot be pulled out, an accordingly the wall 1 can be supported by the anchors 4, and further, the inside foundation improving part 2 prevents the wall 1 from being shifted toward the excavating side. Further, the foundation improving part 3 may be laid vertically in parallel with the wall 1, or obliquely thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a retaining method that allows root cutting and excavation without cutting and tensioning.

[Conventional technology]

To prevent retaining walls from falling or moving in the open direction due to soil excavation by root cutting,
Kiribari is applied to the inside of the retaining wall.

However, when using cutting and tensioning in this way, it requires labor-intensive post-work such as processing unsatisfactory holes due to cutting and tensioning in the basement frame, processing joints for underground external walls that are retaining walls, and transporting removed cutting and tensioning materials. Is required.

Therefore, a construction method for retaining walls that does not use shearing was investigated.
Methods include sloping excavation to maintain slope stability by creating an appropriate slope, anchoring by pulling the head of sheet piles that serve as retaining walls, and construction methods that increase safety against slips by building diagonal piles underground. attempted.

[Problem to be solved by the invention]

However, these methods are only possible when the ground is of relatively good quality.

In particular, the second method of using a ground anchor could only be used when the soil quality in the area into which the anchor was inserted was of good quality (firmly compacted soil).

It is an object of the present invention to provide a mountain retaining construction method that eliminates the disadvantages of the conventional example and allows construction of a mountain retaining wall without cutting and tensioning using ground anchors even in soft ground.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention improves the ground at appropriate locations on the inner side of the mountain retaining wall and on the outside, and from this mountain retaining wall to the outside of the mountain retaining wall. The gist is that a ground anchor is placed over the ground improvement area so that its tip is anchored within the ground improvement area.

[Effect]

According to the present invention, the tip of the ground anchor is located in improved quality ground, and care is taken to prevent the anchor from being pulled out.

In addition, the bottom layer inside the mountain retaining wall has also been improved to provide high-quality ground, and this area can prevent the mountain retaining wall from moving toward the excavation side.

In this way, the excavation side of the mountain retaining wall without cutting and cutting, that is, the part where the basement of the building is constructed, becomes open, making it easier to excavate the earth and construct the frame.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 is a side view showing one embodiment of the mountain retaining method of the present invention.
1 in the figure is the retaining wall.

Various types of retaining walls 1 can be adopted depending on the situation as long as they can withstand earth pressure and water pressure, such as column piles made of soil mortar or underground continuous walls made of concrete. In addition, when the water level is usually low, there are various options such as steel sheet piles or a combination of H-shaped steel and wooden horizontal sheet piles.

The mountain retaining wall 1 will be constructed, and accordingly, soil improvement 2 will be carried out over the entire area of the bottom part inside the mountain retaining wall 1 (on the side where the building will be built).
administer.

In addition, ground improvement 3 was performed at appropriate locations outside the retaining wall 1.

In this embodiment, this ground improvement 3 is performed on the outside of the mountain retaining wall 1 at approximately the same level as the ground improvement 2 inside the mountain retaining wall I.

Note that this ground improvement 3 does not need to be carried out over the entire area, but only in the necessary range in relation to the ground anchor, as will be described later.

There are no particular limitations on the method of performing these soil improvement 2 and soil improvement 3; for example, the improvement (grout) material may be injected at ultra-high pressure from the lower end of the rod to cut the ground and at the same time mix and stir soil particles and grout; Suitable methods include a high-pressure jet mixing method in which a cylindrical solidified body is created by displacement, and a deep mixing method in which a deep layer is solidified into a columnar shape by mechanical stirring.

High-pressure jet injection mixing treatment methods include the JMM method, which injects high-pressure cement slurry from the tip of a stirring blade attached to the tip of a rod, and the column jet method, which uses a column machine. Jet construction methods may also be combined.

A ground anchor 4 was disposed from the mountain retaining wall 1 to the outer ground improvement part 3 so that its tip was fixed within the ground improvement part 3.

This ground anchor 4 was installed by excavating the soil inside the retaining wall 1, that is, on the side of the building, and when the ground anchor 4 at the top could be installed, the anchor work was carried out and placed, and the digging was continued. By the way, we will be working on the ground anchor 4 at the bottom.

The number of ground anchors 4 in the vertical direction and the interval in the horizontal direction may be determined depending on the depth of excavation and the magnitude of earth pressure.

If you do this, the tip of the ground anchor 4 will be connected to the ground improvement 3.
The anchor 4 is located in good quality ground so that it cannot be pulled out, and the retaining wall 1 is supported by the ground anchor 4.

Moreover, the movement of the mountain retaining wall 1 toward the excavation side can be prevented at the ground improvement 2 portion of the bottom base inside the mountain retaining wall 1.

In detail, tensile forces PL and P2 are generated in the ground anchor 4 due to the soil pressure and water pressure W1.

Then, the tensile force P1 is P3, P4, and P2 in the ground improvement 3.
is divided into P5 and P6.

Upward component force P3. P5 is suppressed by the weight of the soil improvement 3 and the weight W2 of the upper soil and water.

Sideways component force P4. P6 acts on the retaining wall 1 as W3.

This W3 is supported by the ground improvement 2 via the retaining wall 1 (W4).

If W2>P3+P5, the retaining wall 1 can be prevented from moving toward the excavated oven (toward the building 5 side).

The thickness of the ground improvement 3 is determined by the required anchorage length of the ground anchor 4.

Due to such a balance of forces, the mountain retaining wall 1 does not require cutting even on soft ground such as reclaimed land in the Tokyo ditch.

In addition, the part to which the ground improvement 3 is applied can be selected as appropriate, and as another example, as shown in FIG. Retaining wall 1
in a diagonal direction, and as shown in Figure 4, the retaining wall 1
It varies from above ground in the vertical direction parallel to the above.

The angle of the ground anchor 4 also differs depending on the position of the ground improvement 3.

In addition, as shown in Fig. 6, only the area around the ground anchor 4 may be subjected to ground improvement 3, or as shown in Fig. 7, the area around the ground anchor 4 may not be continuous in the horizontal direction. It is also possible to perform ground improvement 3.

〔Effect of the invention〕

As described above, the mountain retaining construction method of the present invention enables the construction of mountain retaining walls without shearing using ground anchors even in soft ground, and by eliminating the shearing, it is possible to construct the excavation side, that is, the basement of the building. Since this section functions as an oven, soil excavation and construction of the structure become easier.

In addition, on good quality ground that is not soft ground, a short ground anchor will be sufficient, making it possible to construct a mountain retaining wall without shearing even when the distance to neighboring land is short.

In addition, since the ground is improved, even sandy ground can be prevented from liquefying during an earthquake.

[Brief explanation of drawings]

FIG. 1 is a side view showing the first embodiment of the mountain retaining method of the present invention;
Fig. 2 is a side view showing the second embodiment of the above, Fig. 3 is a side view of the third embodiment of the above, Fig. 4 is a side view of the fourth embodiment of the above, and Fig. 5 is the first embodiment. FIG. 6 is a plan view showing a fourth embodiment of the present invention, and FIG. 7 is a plan view showing a fifth embodiment of the same. ■... Mountain retaining wall 2... Ground improvement 3... Ground improvement 5... Building 4... Ground anchor

Claims (1)

[Claims] Improving the ground at appropriate locations on the inner bottom and outside of the mountain retaining wall, and placing a ground anchor from this mountain retaining wall to the soil improved area outside the mountain retaining wall so that its tip is anchored within the ground improved area. The mountain retaining method is characterized by the fact that it is installed in