JPH04124317A - Improvement of foundation ground for building - Google Patents

Abstract

PURPOSE:To obtain a sure support by forming a peripheral soil cement solidified body surrounding the outer periphery of a building foundation ground and forming a lattice viewed in plane at the lower part of the bottom of the building and further, forming the soil cement solidified body reaching the supporting layer. CONSTITUTION:A curing material for the outer peripheral part of the foundation ground 1 of a building to be constructed is injected to reach the depth of the supporting layer by use of a rod with agitating blades for excavating and agitating to form the outer peripheral soil cement solidified body 3 continuously surrounding the ground 1. Next, in the inside ground surrounded by the solidified body 3, a curing material is injected, agitated to reach the supporting layer from the depth of the building bottom by use of a rod with agitating blades to form the supporting soil cement solidified body 6 continuously arranged to form a lattice, viewed in a plane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for improving the foundation ground of a building constructed on soft ground, such as on a waterfront.

[Problem to be solved by the invention]

Conventionally, when constructing a building on soft ground, it is difficult to perform mountain retaining and root cutting work for the underground framework of the building's foundation, and there is a risk of liquefaction during an earthquake, leading to the destruction of the building. There were problems such as the difficulty in designing the support piles to support the structure.

This invention aims to solve the above-mentioned problems, and improves the building foundation ground to make work safer and more efficient in underground structure construction, prevent liquefaction during earthquakes, and enable reliable building support. To propose a law.

[Means to solve the problem]

The method for improving building foundation ground, which is the invention of (1), is to excavate and stir the outer periphery of the foundation ground of a building by injecting and stirring a solidification material using a rod with stirring blades to a depth that reaches the support layer. The soil cement is mixed with a solidifying material to form a continuous outer soil cement solid surrounding the outer periphery of the building foundation ground, and the solidifying material is injected into the inner ground from the bottom of the building to a depth that reaches the support layer, excavated, and stirred. It is characterized by forming a continuous supporting soil cement solidified body in a lattice shape in plan view below the bottom of the building.

The improved method resulting from the invention of (2) is the improved method of (1) above,
Furthermore, a solidifying material is injected onto the support layer of the inner ground to cover the upper surface of the support layer to form an impermeable soil cement solid body.

C Embodiment] The following will be explained with reference to the illustrated embodiment. As shown in Figure 1-2, solidification material is injected into the outer circumference of the foundation ground 1 of the building to be constructed to a depth that reaches the support layer 2 using a rod with stirring blades, and stirred, and the excavated soil and solidification material are then mixed. are mixed to form a continuous outer periphery soil cement solid body 3 surrounding the outer periphery of the foundation ground I of the building.

Figure 3 (a), (b), (C), (d), (e
) shows a construction procedure for forming a solid body 3 using a rod 5 having a stirring blade 4. In (a), the rod 5 is positioned, and in (b), the solidifying material slurry is applied to the rod 5.
It is discharged from the tip, excavated at the same time, and stirred and mixed with the excavated soil. (C) Excavate to a predetermined depth, stop discharging the solidified material, and (6) pull up the rod 5 without continuing stirring. (e) The rod 5 is pulled up. This process is repeated to construct a continuous outer soil cement solid body 3.

The inner ground 1 surrounded by the outer periphery soil cement solidified body 3 is also solidified from the depth of the building bottom to the depth reaching the support layer 2 using a rod 5 having stirring blades 4 according to the construction procedure shown in FIG. The material is injected, excavated, and stirred to form a continuous support soil cement solid body 6 in a lattice shape in plan view below the bottom of the building.

Furthermore, the support layer 2 of the ground inside the outer peripheral soil cement solid body 3
A solidifying material is injected into the upper part of the solidifying material and mixed by stirring to cover the upper surface of the support layer 2 to form an impermeable soil cement solidified body 7.

In this embodiment, since the support layer 2 is a water-permeable layer, the impermeable soil cement solid body 7 is formed on the upper layer thereof, but this is not necessary if the support layer 2 is a water-impermeable layer. If the foundation ground 1 is saturated and there is a risk of liquefaction occurring during an earthquake, water will be dewatered using the well point construction method. In this case, since the outer periphery is surrounded by the soil cement solid body 3, there is no fear of ground subsidence at the periphery.

In addition, piles can also be used in cases where the building load is large or the supporting layer is deep. Figure 5 shows piles 8 at grid intersection points of the supporting soil cement compact 6.
This is an example of improving the foundation ground by building and reinforcing it.

[For production]

This invention consists of the above configuration. The building 9 constructed on the foundation ground 1 improved in this way is as shown in Fig. 4.5, and the outer periphery of the foundation of the building 9 is surrounded by the outer periphery soil cement solid body 3 that reaches the support layer 2. The building bottom 10 is the support layer 2
Supporting soil cement solidified body 6 in the form of a lattice in plan view reaching
The inside of the foundation ground 1 is supported by the outer soil cement solid body 3.
and is surrounded by the impermeable support layer 2 or the impermeable soil cement solidified body 7 formed on the impermeable support layer 2, thereby forming an impermeable block.

Also, when constructing a building on the foundation ground improved in this way, the outer soil cement solid body 3 becomes a retaining wall,
The lattice-shaped supporting soil cement solid body 6 functions as a strut for the retaining walls on the four surrounding sides, and suppresses deformation of the retaining walls during root cutting and excavation.

Incidentally, by inserting a steel frame or reinforcing bars into the soil cement aggregate 3 to increase the rigidity and strength of the retaining wall, it is also possible to prevent deformation of the retaining wall and to ensure safety.

〔Effect of the invention〕

This invention has the following effects.

■ The building is supported by soil-cement solids that form a continuous grid that reaches the support layer, providing reliable support even on soft ground.

■ Since the foundation ground forms an impermeable block, there is no risk of liquefaction even if the ground is soft.

■ During building construction, the outer soil cement solidified body acts as a retaining wall, and the supporting soil cement solidified body functions as a strut, making it possible to improve the efficiency of underground framework construction.

[Brief explanation of drawings]

Figures 1 and 2 are a plan view and a longitudinal cross-sectional view of the foundation ground according to the improved method of the example, and Figures 3 (a), (a), (c). (d) and (e) are cross-sectional views showing the construction procedure of the soil cement solidified body, Figures 4 and 5 are longitudinal and cross-sectional views of the building constructed on the improved foundation ground, and Figure 6. is a cross-sectional view showing an example of foundation ground improvement using piles. DESCRIPTION OF SYMBOLS 1...Foundation ground, 2...Supporting layer, 3...Peripheral soil cement solidified body, 4...Stirring blade, 5...Rod,
6... Supporting soil cement solidified body, 7... Impermeable soil cement solidified body, 8... Pile, 9... Building,
10... Bottom of the building. Figure Figure] Figure (a) (b) (C) (d) (e)

Claims (2)

[Claims] (1) Excavate and stir the outer periphery of the building's foundation ground using a rod with stirring blades to a depth that reaches the support layer, mix the excavated soil and the solidifying material, and then A continuous outer soil-cement solidified body surrounding the building is formed, and a solidification material is injected into the inner ground from the bottom of the building to a depth that reaches the support layer, excavated and stirred, and a grid-like structure is formed below the bottom of the building in plan view. A method for improving building foundation ground characterized by forming a continuous supporting soil-cement solid. (2) The outer periphery of the building's foundation ground is injected with a solidification material using a rod with stirring blades to a depth that reaches the support layer, and the solidification material is injected and stirred, and the excavated soil and the solidification material are mixed to form the outer periphery of the building foundation ground. A continuous outer soil-cement solidified body is formed surrounding the building, and a solidifying material is injected into the ground from the bottom of the building to a depth that reaches the support layer, excavated, and stirred to form a lattice-like structure in plan view below the bottom of the building. It is characterized by forming a continuous supporting soil cement solid body, and further injecting a solidifying material onto the support layer of the inner ground to cover the top surface of the support layer and forming an impermeable soil cement solid body. Method for improving building foundation ground.