JPH04336117A - Landslide protection stabilizing construction method - Google Patents

Abstract

PURPOSE:To certainly reinforce a landslide protection wall without extending an anchor longer. CONSTITUTION:A curing agent is poured into a soil in an area behind a landslide protection wall 3 deposited along the planning line of an excavating area 2 to form a hard ground layer 4. The landslide protection wall 3 and the hard ground layer 4 are mutually connected through anchors 6(6a-6c) at every time when ground soil inside the landslide protection wall 3 is excavated as much as a fixed depth.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stabilizing a retaining wall during excavation of a vertical hole.

0002

[Prior Art] In order to excavate a vertical hole in building construction, tunnel construction, etc. (hereinafter simply referred to as building construction, etc.), a pile of sheet piles, continuous cement walls, etc. is usually constructed along the planned line of the excavation area. After the retaining wall is cast, the inside of the retaining wall is excavated to prevent the ground soil from collapsing due to the retaining wall.

[0003] In recent years, with the increasing scale of building construction work, the depth of vertical holes has tended to become larger and larger, and the earth pressure applied to retaining walls has also increased accordingly. Conventionally, when excavating a vertical hole of such great depth, an anchor is extended from the retaining wall every time a predetermined depth is excavated, and the tip of the anchor is anchored in the ground around the excavated area. The retaining walls were to be reinforced.

0004

[Problem to be solved by the invention] However, according to the method of reinforcing mountain retaining walls using anchors, the reinforcing effect is lost if the ground on which the tip of the anchor is anchored is soft, so it is necessary to find a strong ground. In some cases, the anchor must be extended by several tens of meters, which poses a problem in that construction requires a large amount of man-hours and time. Furthermore, as building construction work is often carried out in limited spaces these days, there is a natural limit to the extension of anchors, and situations often arise where anchor reinforcement has to be abandoned.

[0005] As an alternative to anchor reinforcement,
There is also a method of building reinforcing horizontal beams between opposing retaining walls, but in this case, the working space in the vertical hole is narrowed by the horizontal beams, which significantly impedes work efficiency and significantly shortens the construction period. Not only is the work being extended, but it is also causing many problems in terms of work safety.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a stabilizing construction method for retaining a retaining wall that can reliably reinforce the retaining wall without extending the anchor for a long time. .

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a hard ground layer hardened with a hardening agent near and around an excavation area, and forms a hard ground layer around the excavation area along a planned line of the excavation area. The present invention is characterized in that each time the inside of the cast mountain retaining wall is excavated to a predetermined depth, the mountain retaining wall and the hard ground layer are connected by an anchor.

In the present invention, the type of the hardening agent is not particularly limited, and for example, cement slurry, lime, water glass-based or polymer-based chemicals can be used. In addition, any method can be used to form this hard ground layer, such as simply inserting an injection pipe into the soil and injecting the hardening agent under pressure, or driving a hollow casing into the soil and supplying the hardening agent inside the casing. A method of filling the hardening agent into the area where the casing was pulled up, or a method of inserting a hollow casing with stirring blades into the soil and stirring the hardening agent supplied through the casing and the ground soil while rotating the casing. can be selected. Furthermore, the number of anchors is also arbitrary, and can be selected appropriately depending on the width of the excavated area and the depth of the vertical hole to be excavated.

Further, in the present invention, the method for pouring the mountain retaining wall is arbitrary; for example, sheet piles may be continuously driven to form a mountain retaining wall, or cement-based materials may be cast on-site to form a mountain retaining wall. Also good. Furthermore, in the present invention, either the step of hardening with a hardening agent to form a hard ground layer or the step of pouring a retaining wall may be performed with priority.

0010

[Function] In the mountain retaining stabilization method constructed as described above, by fixing the tip of the anchor to the hard ground layer, the pull-out resistance of the anchor increases significantly, and the reinforcement of the mountain retaining wall becomes reliable. Moreover, since the hard ground layer is formed close to and around the excavated area, the retaining wall can be reinforced without extending the anchor for a long time.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, 1 is the ground, and 2 is an excavation area. In this embodiment, sheet piles are first driven along the planned line of the excavation area 2 to form a retaining wall 3. Next, a hardening agent is injected into the soil at a location spaced a predetermined distance rearward from this retaining wall 3 to form a hard ground layer 4. The hard ground layer 4 is formed to surround almost the entire excavation area 2 and to be slightly deeper than the depth of the vertical hole 5 to be excavated.

[0013] Thereafter, the ground soil inside the retaining wall 3 is excavated using a suitable excavation machine. Then, once the excavation has been excavated to a predetermined depth, the excavation is temporarily stopped (the ground surface at this time is shown by the two-dot chain line in Figure 1), and a small diameter hole is excavated from the retaining wall 3 to the hard ground layer 4 in the excavation area 2. A plurality of anchors 6a are inserted into each hole at a predetermined pitch in the circumferential direction, and the tip of the anchor 6a is fixed in the hard ground layer 4, while the base end is fixed in the retaining wall 3. Tighten and fix using the fastener 7. Next, excavation of the ground within the excavation area 2 is started again, and when the excavation has progressed to a predetermined depth, the retaining wall 3 and the hard ground layer 4 are attached to the anchor 6b again by the same procedure as described above.
After that, further excavation is carried out and anchor 6 is connected.
c connects the mountain retaining wall 3 and the hard ground layer 4. In addition, in FIG. 2, the anchor is generally indicated by the reference numeral 6.

In this way, the vertical hole 5 of a predetermined depth is formed, but since the tip of the anchor 6 is fixed to the hard ground layer 4, its pull-out resistance increases significantly, and as a result, The mountain retaining wall 3 is sufficiently reinforced and there is no need to worry about landslides. Moreover, by providing the hard ground layer 4 close to the excavated area, there is no need to extend the anchor 6 long in search of strong ground, and construction efficiency is improved. Furthermore, the part D between the mountain retaining wall 3 and the hard ground layer 4 (Fig. 1)
The ground around the vertical hole 5 is extremely stable because they work together through the anchor 6 to resist earth pressure.

[0015]

Effects of the Invention As explained above in detail, according to the mountain retaining stabilization method according to the present invention, a hard ground layer is formed near and around the excavation area, and anchors are attached to this hard ground layer. Since the tip of the anchor is anchored, the retaining wall can be reliably reinforced without having to extend the anchor for a long time, which not only significantly shortens the construction period, but also significantly reduces construction costs. Additionally, the area between the retaining wall and the hard ground layer is integrated and becomes extremely stable, further increasing the safety of the construction work. Moreover, since it is possible to restrict the expansion of the construction area to adjacent land, it is suitable for use in building construction, tunnel construction, etc. where there are many space constraints.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a construction mode using the stabilizing construction method for retaining mountains according to the present invention.

FIG. 2 is a plan view showing a construction mode using the Motoyama-dome stable construction method.

[Explanation of symbols]

1. Ground 2. Excavation area 3 Mountain retaining wall 4 Hard ground layer 5 Standing hole 6 Anchor 6a Anchor 6b Anchor 6c anchor

Claims (1)

[Claims] [Claim 1] A hard ground layer hardened with a hardening agent is formed near and around the excavated area, and the inside of a retaining wall cast along the planned line of the excavated area is excavated to a predetermined depth. A method for stabilizing mountain retaining construction, characterized in that the mountain retaining wall and the hard ground layer are connected by anchors.