JPH02171426A - Basement building process - Google Patents

Abstract

PURPOSE:To make it possible to efficiently build a basement wall by laying segments in the ground which has been loosened by digging, and by forcing a cutting edge part provided on the lower end of the segment through the inter mediary of a vertically telescopic drive means into the ground, and successively installing a new segment. CONSTITUTION:Segments 4 are arranged on the ground G which has been loosed by digging with the use of an earth auger or the like. Then, a cutting edge part 2 is arranged at the lower end of the segment 4 through the intermediary of a vertically telescopic drive means 3 such as a hydraulic jack or the like, so that the forward end of the cutting edge part 2 is directed downward. Then the vertically telescopic drive means 3 is driven to force the cutting edge part 2 into the ground G. After the sediment surrounding the cutting edge part 2 being removed, the vertically telescopic drive means 3 is retracted, and then a new segment 4 is disposed between the cutting edge part 2 and the aforementioned segment 4, and both segments 4 are fastened together by means of bolts. Then, the above-mentioned steps are repeated so as to extend the basement wall, successively.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an underground construction method suitable for use in deep underground construction, bridge foundations, etc. for effective use of land in urban areas.

``Conventional technology'' Conventionally, the open-cut method was used to construct a basement floor by constructing a retaining wall in advance and performing internal excavation while temporarily installing shoring. Continuous wall, columnar wall,
Underground continuous walls, sheet piles, etc. are used. However, in the case of underground continuous walls and columnar walls, the cross section of the retaining wall is constant and it is difficult to create a variable cross section.

In addition, continuous walls and columns of walls are used in some cases, but in order to cope with the in-plane shearing force, the cost is high, and most of them are used for temporary construction.

In mountain retaining walls that use sheet piles, pulling out the sheet piles after underground construction has a large impact on the surrounding ground, and poor backfilling can cause ground collapse.

Furthermore, for mountain retaining walls with low rigidity, it is necessary to take into account deformation during excavation.

There are many basements and basement floors on ultra-soft ground (there are restrictions on the construction period, and in recent years, the reverse construction method has been adopted as a highly rigid underground floor construction method to minimize the impact on surrounding structures. Contrary to the normal construction method, the reverse construction method involves pouring beams or slab concrete, etc. of the permanent structure from the upper floor to the lower floor along with the root cutting, and uses this as shoring. This is a construction method in which construction is carried out sequentially to the lower floors while supporting the earth retaining wall, which inevitably increases costs compared to the sequential construction method because the work space is narrow and the number of transportation steps is large. The quality of the treatment at the joints will affect the load transmission and water-stopping performance of the structure.

``Problem to be solved by the invention'' During excavation, the outer wall made up of segments is used as a retaining wall, and this is directly applied to the main body wall, so the impact on the surrounding ground during excavation is minimized. thing. By creating a convenient joint structure that prevents groundwater from penetrating through the underground outer wall and can handle in-plane shearing force during earthquakes, by easily ensuring a certain quality of materials, and by shortening the construction period. This provides an underground construction method that aims to reduce costs.

"Means for Solving the Problem" In order to achieve the above object, the present invention provides a construction method for constructing an underground structure by placing an outer wall assembled with segments into the ground, and an earth auger. A step of loosening the ground by such means as above, arranging a segment on the ground, providing a vertical telescopic drive means at the lower end of the segment, and a state in which the segment is connected through the vertical telescoping drive means and with its tip facing downward. a step of providing a cutting edge portion with a blade, pushing the cutting edge portion into the ground by disengaging the vertically telescopic drive means; a step of discharging earth and sand in the ground surrounded by the cutting edge portion; The present invention is characterized by comprising the step of constructing an underground outer wall by contracting the means and newly connecting a segment to the lower end surface of the segment.

"Function" In this invention, after the ground is loosened by means such as an earth auger, a segment is placed on the ground, and a vertically telescoping drive means such as a hydraulic jack is provided at the lower end of the segment. A cutting edge is provided with the tip facing downward, and the cutting edge is pushed into the ground by extending the vertically extending/contracting drive means, and then the ground surrounded by the cutting edge is pushed into the ground. The underground outer wall is constructed by removing the earth and sand, and inserting new segments between the cutting edge part and the segment formed by retracting the vertically extending/contracting drive means, and connecting these segments with bolts. By doing this, it is easy to push the cutting edge into the ground, and it is also possible to introduce pre-stressed segments in which the segments that make up the outer wall are made in advance at the factory, which shortens the construction period and provides high strength. The construction period can also be shortened by proceeding simultaneously with floor construction.

"Example" The underground construction method of the present invention will be explained with reference to FIGS. 1 to 8. FIG. 1 is a diagram showing the construction of the underground structure according to the present invention, in particular, an enlarged view of the lower end portion of the structure. In the figure, the code l indicates an underground structure, and the structure l is made up of a thick timber 1a installed perpendicular to the ground G and
A slab 1b provided parallel to the ground G, a stub 1c provided parallel to the ground G near the 1] side of the cutting edge portion 2, which will be described later, and an intermediate girder erected perpendicular to the ground G. ,ld
.

It is composed of. A hydraulic jack 1e is appropriately installed on the stubble 1c.

A cutting edge portion 2 is installed below the side surface of the thick end material 1a with the tip facing downward, and a hydraulic jack 3 as a vertically extending/contracting drive means is installed at the upper end of the cutting edge portion 2. Further, above the hydraulic jack 3, and on the side surface of the end member [a], segments 4.4 are provided.

Next, the horizontal construction method for underground structures of the present invention will be explained with reference to FIGS. 2 to 8.

First, as shown in Fig. 2, the location on the ground G where the outer wall of the structure will be constructed is accurately determined, a ruler is set, and the earth auger IO is used to excavate to the required depth. An injection material such as a hardening material is injected into the loosened ground G1 and mixed with the ground G to make it uniform so that the cutting edge part 2 can be press-fitted smoothly. Depending on the ground, only loosen &i. In addition, in areas where groundwater needs to be blocked, a water-stopping wall is created in advance by mixing and stirring with the soil in situ to deal with boiling, etc. that occurs as the cutting edge portion 2 advances. .

Next, as shown in FIG. 3, the cutting edge portion 2 is placed in the ground Gl that has been loosened by the process shown in FIG.

Next, as shown in FIG.
] Install the segment 4 at the upper end of the pressurized part of the pressure jack 3. Furthermore, intermediate piers d and l are placed parallel to the cutting edge portion 2, the hydraulic jack 3, and the segment 4 at a predetermined interval.
d, ...... is poured. This intermediate position,
ld, . . . shall be installed in the basement floor (the required number to support the weight of the building).

Thereafter, the pressure-receiving portion of the hydraulic jack 3 at the lower end of the segment 4 is extended to take a reaction force from the segment 4, and the initial sinking of the cutting edge portion 2 is performed.

Next, as shown in FIG. 5, the pressure section of the hydraulic jack 3 is retracted, and a new segment 4 is inserted into the space created between the segment 4 and the pressurized section of the hydraulic jack 3. Following this, the pressurized part of the hydraulic jack 3 is extended to push the cutting edge part 2 into the ground. Earth and sand are removed from the area surrounded by the outer wall by the segments 4.4, . . . formed as the cutting edge portion 2 advances.

After repeating the steps shown in FIG. 5, the slab lb is provided at a certain depth parallel to the ground G and extending over the end piece 1a, as shown in FIG.

Then, as shown in FIG. 7, shoring 5 is provided from the intermediate pile 1d toward the underground outer wall. As a result, the ground G
be able to cope with deformation of the underground outer wall due to lateral pressure from

The underground structure 1 h<? M be built.

In the underground construction method, which consists of the above-mentioned process, the thickness and cross-section of the segments forming the underground outer wall can be freely changed depending on the magnitude of lateral pressure, and they can also be used as the main wall, as well as a composite cross-section by pouring secondary lining concrete. It can also be used as

In addition, compared to cast-in-place concrete, since it is manufactured in a factory, prestress can be introduced as high-strength concrete, so the cross section of the member can be made smaller.

Furthermore, the lateral pressure from the exterior walls is received by the slabs and temporary supports of the underground structure using the reverse pouring method, but the length of the beams is smaller than in the conventional cut-and-cover construction method.

"Effects of the Invention" As explained above, the underground construction method of the present invention includes the step of excavating the ground using means such as an earth auger, arranging a segment on the ground, and installing a vertically telescopic drive means at the lower end of the segment. and a cutting edge portion is provided with the tip facing downward via this vertically extending and contracting drive means,
pushing the cutting edge into the ground by extending the vertically telescoping drive means; removing earth and sand in the ground surrounded by the cutting edge; and retracting the vertically telescoping drive to move the cutting edge into the ground. Since this is an underground construction method that includes the step of constructing an underground outer wall by connecting new segments to the lower end surfaces of the segments, it is easy to push the cutting edge into the ground. In addition, by introducing factory-made prestressed segments, the construction period can be shortened and a high-strength outer wall can be obtained.

In addition, the wall thickness and cross section of this segment can be freely changed depending on the magnitude of lateral pressure, and it can be used as the main wall of a structure, and can also be used as a composite cross section by pouring secondary lining concrete.

In addition, although the lateral pressure from the outer wall is received by the slab and temporary shoring of the underground structure using the continuous hammer construction method, the amount of material for the struts can be reduced compared to the conventional strut construction method.

Furthermore, the construction period can be shortened by simultaneously constructing the ground floor.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the construction state of the underground structure of the present invention, and is an enlarged view of the lower end of the structure. FIGS. 2 to 8 are diagrams showing the steps of the underground structure construction method of the present invention. ...Ground, ...Structure, ...Stub material, ...Slab, ...Strut, ...Intermediate pile, cutting edge, hydraulic jack (vertical telescoping drive means), segment, a ′- b・・・ C゛pad ・・・ 2 ・・・ ・・・ 3 ・・・ ・・・ ４ ・・・ ・・・ Shoring...Earth auger.

Claims (1)

[Claims] This is a construction method for constructing an underground structure by placing an exterior wall assembled with segments into the ground, which includes a step of digging out the ground using means such as an earth auger, and a step of placing segments on the ground. A vertical telescoping drive means is provided at the lower end, a cutting edge is provided with the tip facing downward through the vertical telescoping driving means, and the cutting edge is pushed into the ground by extending the vertical telescoping drive. a step of removing earth and sand in the ground surrounded by the cutting edge portion, and contracting the vertically extending and contracting drive means,
An underground construction method comprising the step of constructing an underground outer wall by newly connecting a segment to the lower end surface of the segment.