JPH11181806A - Heaving preventing method and construction of underground building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply, reliably, effectively, and economically prevent the occurrence of heaving. SOLUTION: A heaving preventing method is such that a tip reaches an aquiclude impermeable layer ground 1 and by constructing and erecting earth retaining walls 4 and 5, a heaving preventing pile (a) is inserted through a building construction region (b), formed above the aquiclude impermeable layer ground 1 and surrounded in a permeable layer ground 2, and the aquiclude impermeable layer ground 1, and penetrated and driven through a confined aquifer ground 3 below the aquiclude impermeable layer ground 1. In this case, drive of the heaving preventing method is such that mortar or concrete (c) is placed on at least the confined aquifer ground 3 and the aquiclude impermeable layer 1 part of a bored hole formed through the permeable layer ground 2, the aquiclude impermeable layer ground 1, and the confined aquifer ground 3, and a pile material (d) made of a steel, such as an H-steel or a steel pipe, is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing swelling and a method for constructing an underground building.

[0002]

2. Description of the Related Art Bulging can occur when there is an impermeable ground between the bottom of the root cutting and the vicinity of the tip of the retaining wall, and there is a pressurized aquifer underneath. It is said that there is a risk of causing an accident.However, in the past, the methods for preventing swelling were to reduce the pressure with a deep well, to lower the retaining wall to an impermeable layer and close it, and to improve the bottom plate And a method of dividing the basement and constructing it.

[0003]

However, the method of reducing the pressure by the deep well has the drawback that the treatment capacity of the public sewerage system due to drainage becomes a problem, or that the surrounding ground may be compacted and settled due to a decrease in water level. The method of lowering the earth retaining wall to the impermeable layer ground and closing it has the drawback that the impermeable layer ground is accurately assumed, and it is technically difficult to securely close the ground and the construction cost increases. The method of closing off by improving the bottom plate has the disadvantages that the reliability of the injection of the chemical solution for improving the bottom plate is not always high and the cost is high. The method of dividing the basement and constructing it has the drawback that there is a limit to the operation of deep excavation, the construction period is long, and the joint of the skeleton is increased.

[0004] The inventors of the present invention have intensively studied to develop a method for preventing swelling which has improved these disadvantages and a method for constructing an underground building using the same, and completed the present invention. It is relatively simple, yet effective and economical to prevent.

[0005]

According to the method of the present invention, the swelling prevention method of the present invention uses the earth retaining walls 4 and 5 which are constructed with the tip reaching the hard and impermeable layer ground 1 and the hard and impermeable layer ground 1 is provided. In the building construction area b formed in the permeable ground 2 above, the swelling prevention pile a is made to penetrate the difficult / impermeable ground 1 and the lower part of the hard / impermeable ground 1. The content is to penetrate into the pressurized aquifer ground 3.

In the above description, the swelling prevention pile a is cast at least by the drilling of the permeable ground 2, the difficult / impermeable ground 1 and the pressurized aquifer ground 3 in the pressurized aquifer ground 3. It is preferable to inject and fill mortar or concrete c into the portion of the hard / impermeable layer ground 1 and to embed a steel pile material d such as an H-shaped steel or a steel pipe into the portion.
If an expanded bottom pile is adopted as the swelling prevention pile a, there is a merit that the length of the tip side penetrating the pressurized aquifer ground 3 can be shortened.

The method for constructing an underground building according to the present invention is characterized in that the required number of the piles for pile-prevention a is laid in a predetermined arrangement by the above-mentioned pile-prevention method, and the pile-prevention work is carried out.
Excavation in the building construction area b surrounded by the retaining walls 4 and 5 and installation of the shoring 6 are repeatedly performed, and a lining plate 7 is constructed on the upper end of the slab prevention pile a, and a bottom plate is provided on the bottom of the root cutting. The concrete 8 is constructed, the skeleton 9 of the target building is constructed,
Thereafter, the pile-preventing pile a is cut at the bottom of the root cutting to remove the portion of the pile-preventing pile a located in the excavation space b ', and is back-filled in the excavation space b'. Performs earthwork.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. 1 is a poorly permeable or impermeable ground made of cohesive soil or the like, that is, a poorly / impermeable ground.
Is a permeable ground above the difficult / impermeable ground 1, 3 is a pressurized aquifer ground such as sandy soil below the hard / impermeable ground 1, 4,
Reference numeral 5 denotes a retaining wall constructed and established at a required interval necessary for surrounding and forming the building construction area b in the permeable ground 2, each end of which is formed on the hard / impermeable permeable ground 1. Has been reached.

Reference numeral a denotes a slab prevention pile piled in the building construction area b surrounded by the retaining walls 4 and 5, and a required length of the tip side penetrates the pressurized aquifer ground 3. ing. This swelling prevention pile a is constructed as follows. A pile driver is set at a predetermined position, and a hole is drilled by an auger screw to reach a required depth (for example, at least 9 m) of the pressurized aquifer ground 3 from the ground surface.

After confirming that the drilling has reached the predetermined depth, the mortar or concrete, which has been previously kneaded and mixed, is pumped by a grout pump through an auger shaft hollow shaft, and injected from the tip of the auger, thereby covering the hole. The portion of the confined aquifer ground 3 and the hard / impermeable aquifer ground 1 is filled. In this case, the auger head is pulled up while being kept inserted at about 1 m without being separated from the mortar surface, pulled out while rotating the auger screw forward, and discharged.

After pulling out the auger, a steel pile material d such as an H-shaped steel or a steel pipe is immediately erected in the mortar or concrete c which is filled and poured, and is allowed to stand until the mortar or concrete c hardens. As a result, a slab prevention pile a having a structure in which the steel pile material d is embedded in the mortar or the concrete c is constructed.

The above-mentioned mortar or concrete c filling is performed by sealing the space between the steel pile material d and the surrounding ground in the hard and impermeable layer ground 1 and the pressurized aquifer layer 3 so that the ground water is reduced. It is possible to prevent water from leaking above the hard / impermeable layer ground 1 through the hole. In other words, building a steel pile d only by drilling or driving a steel pile d directly into the ground creates an air gap between the ground and the steel pile d, thereby reducing the pressure of groundwater. It is not appropriate because it causes water to leak above the hard / impermeable layer ground 1 and cannot obtain the desired frictional force with the surrounding ground.

The swelling prevention pile a constructed as described above has a steel stake d and a mortar or concrete c firmly adhered and integrated, and the outer peripheral surface of the mortar or the concrete c is covered. The compressed water layer 3 and the hard / impermeable layer ground 1 are pressed against the wall surface of the hole.

The pile a for preventing swelling penetrates through the hard / impermeable layer ground 1 and penetrates into the pressurized aquifer layer 3.
The peripheral frictional force between the outer peripheral surface (pile peripheral surface) of the mortar or concrete c in the pressurized aquifer ground 3 and the peripheral ground is set as a reaction force, and the outer periphery of the mortar or concrete c in the hard / impermeable aquifer ground 1 By setting the frictional force between the surface (pile peripheral surface) and the surrounding ground as the resistance to the lifting pressure acting on the difficult / impermeable layer ground 1, the floor bulging can be prevented.

According to the experiment, the adhesive force between the steel pile material d and the mortar or concrete c is larger than the peripheral frictional resistance of the mortar or concrete c. Adhesion does not break.

After the required number of the piles for pile-up prevention a has been set and set, and the construction for the pile-up prevention has been performed, the building construction area surrounded by the retaining walls 4 and 5 is obtained. Excavation in b and installation of supports 6 such as cutting beams and bulging are repeated, and a lining plate 7 is constructed on the upper end of the slab prevention pile a to temporarily close the upper opening of the excavation space b '. (FIG. 4).

As described above, the swelling prevention pile a can be used as a support stake for supporting the lining plate 7 in addition to preventing the swelling, and this greatly contributes to a reduction in construction cost. Will be.

Then, the bottom concrete 8
(FIG. 5), and furthermore, a frame 9 of a target building (tunnel, subway station building, etc.) is constructed (FIG. 6). Further, the swelling prevention pile a is cut at the root bottom surface to remove the steel pile material d located in the excavation space b ', and the excavation space b' is backfilled with soil ( (FIG. 7).

The swelling prevention pile a is formed as an expanded bottom pile, that is, a widened portion a 'is formed at the tip, so that the penetration length of the pile 3 into the pressurized aquifer ground 3 is improved. Thus, it is also clear that the overall length can be shortened (FIG. 8).

[0020]

As is apparent from the above description,
The following effects can be obtained by the method of the present invention. The anti-blurring pile penetrates through the impervious / impermeable layer ground and penetrates into the confined aquifer ground below it. The friction force between the peripheral surface (pile peripheral surface) and the surrounding ground is defined as the reaction force between the peripheral surface (pile peripheral surface) and the surrounding ground as the reaction force. By making the resistance to the lifting pressure acting on the layered ground, the swelling can be prevented very effectively.Moreover, compared with the conventional swelling prevention method, the construction can be performed easily and reliably. There is an advantage that the construction period can be shortened.

In particular, as in the case of the second aspect, the swelling prevention pile is prepared by injecting and filling mortar or concrete into at least a portion of the borehole in the confined aquifer layer and the hard / impermeable layer. When the steel pile is put in by embedding it, the injection and filling of mortar or concrete seals the gap between the steel pile and the surrounding ground in the hard / impermeable and pressurized aquifer ground. It is possible to carry out the required construction while preventing the pressurized groundwater from leaking above the difficult / impermeable layer through the borehole. By driving pile materials,
A gap is created between the ground and steel piles, making it difficult to pressurize groundwater.
There is no danger that the desired frictional force cannot be obtained between the impervious layer ground and the surrounding ground while leaking water above the impermeable layer ground.

In addition, the pile for preventing swelling constructed in the above-described manner has a steel pile material and mortar or concrete firmly adhered and integrated, and the outer peripheral surface of the mortar or concrete is pressurized and confined. It is pressed against the hole wall surface of the water layer ground and the impervious / impermeable layer ground, and the peripheral friction force between the outer peripheral surface (pile peripheral surface) of mortar or concrete and the surrounding ground in the pressurized aquifer layer is regarded as the reaction force. Also, difficult
By making the frictional force between the outer peripheral surface (pile peripheral surface) of mortar or concrete c and the surrounding ground in the impermeable layer ground, the resistance to the lifting pressure acting on the difficult / impermeable layer ground,
The function of preventing the bulging becomes more certain.

The method of constructing an underground building according to the present invention is to construct a desired frame while reliably preventing the bulging by the bulging prevention method. In other words, the swelling prevention pile can literally prevent swelling and can also be used as a support pile, and it is clear that the construction advantage is extremely large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, in which a retaining wall for surrounding a building construction area is constructed and established in a permeable ground.

FIG. 2 is a cross-sectional view showing a state where a slab prevention pile is cast in a building construction area.

FIG. 3 is an enlarged cross-sectional view of a main part of a slab prevention pile.

FIG. 4 is a cross-sectional view of a state where excavation and support of a building construction area are performed.

FIG. 5 is a cross-sectional view showing a state in which bottom slab concrete is laid and laid in the above excavation space.

FIG. 6 is a cross-sectional view of a state in which a building body of the building is constructed in the above-described excavation space.

FIG. 7 is a cross-sectional view showing a state in which the swelling prevention pile is cut and backfilled.

FIG. 8 is a cross-sectional view of a state in which an expanded pile is cast as a pile for preventing swelling.

[Explanation of symbols]

 a Piling preventing pile a 'Widening part b Building construction area b' Excavation space c Mortar or concrete d Steel pile material 1 Difficult / impermeable layer 2 Permeable layer 3 Pressurized aquifer layer 4,5 Soil Retaining wall 6 Shoring 7 Lining plate 8 Bottom concrete 9 Frame

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Tanaka 2-14-2 Nagatacho, Chiyoda-ku, Tokyo Inside the Japan Railway Construction Public Corporation (72) Inventor Hiroshi Chikyu Tobishima Construction 2nd Sanbancho, Chiyoda-ku, Tokyo Kaoru Kobayashi, Inventor Kaoru Kobayashi, 2nd Sanbancho, Chiyoda-ku, Tokyo Tobishima Construction Co., Ltd. (72) Inventor Hiroshi Matsushima 2nd Sanbancho, Chiyoda-ku, Tokyo Tobishima Construction Co., Ltd. (72 Inventor Yukio Abe 2 Tobanjima Construction Co., Ltd., Sanbancho, Chiyoda-ku, Tokyo

Claims (4)

[Claims] Claims: 1. A building construction area formed in a permeable layer ground above a difficult / impermeable layer ground by a retaining wall constructed by establishing a tip to reach the difficult / impermeable layer ground, A board swelling prevention method characterized in that a board swelling prevention pile is penetrated through the above-mentioned hard / impermeable layer ground and penetrates into a pressurized aquifer layer below. 2. Drilling a hole in a permeable ground, a hard / impermeable ground and a pressurized aquifer ground, and at least a portion of the drilling in the pressurized aquifer ground and the hard / impervious water ground. 2. The method according to claim 1, wherein the mortar or concrete is injected and filled, and a steel pile material such as an H-section steel or a steel pipe is erected therein so as to lay the pile preventing pile. 3. The method according to claim 1 or 2, wherein the pile for preventing swelling is an expanded pile. 4. The method according to claim 1, 2 or 3, wherein after the required number of piles for pile-prevention is driven in a predetermined arrangement and the required pile-prevention construction is performed, In addition to repeatedly excavating and installing shoring in the building construction area surrounded by the retaining wall, installing a lining plate on the upper end of the slab prevention pile, installing bottom slab concrete on the bottom of the root cutting, After constructing the skeleton of the building, cut the above-mentioned anti-blurring pile at the bottom of the root and remove the part of the anti-blurring pile located in the excavation space. A method for constructing an underground building, comprising performing backfill soil construction.