JPS6248011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a continuous underground wall, and more specifically to a method for constructing a continuous underground wall in soft or extremely soft ground.

Conventional methods for constructing underground continuous walls on soft or extremely soft ground include injecting poorly blended salt cement, chemical solutions, etc. The construction method involved improving the surrounding ground, including removing groundwater, and then constructing an underground continuous wall. In such conventional construction methods, the ground improvement is costly, expensive muddy water must be used for subsequent excavation, and the surface of the continuous wall constructed in this way is Because the ground is soft or extremely soft, the surface may be rough or lumpy. Therefore, it was necessary to scrape the surface or add additional hammering after construction, which caused problems in terms of economy and shortening the construction period.

The present invention was developed in view of these technical problems, and involves driving box-shaped steel plate casings into soft ground at predetermined intervals until they reach stable ground, excavating the earth and sand inside the steel plate casings, and then excavating the Reinforced concrete is placed in the casing, and before the concrete in the casing completely hardens, the casing is pulled out to separate and form a preceding panel with semicircular recesses formed at both ends, and the panel is placed between the preceding panels. A pair of plate-shaped iron plates are driven in such a way as to sandwich the two plate-shaped iron plates, and after excavating the earth and sand between the plate-shaped iron plates, reinforced concrete is poured between the plates, and the plate-shaped iron plates are pulled out before the concrete completely hardens. , a method for constructing a continuous underground wall in soft ground, characterized by forming a trailing panel that is integrally connected with the preceding panel. In the present invention, by adopting the above configuration, when constructing an underground continuous wall in soft ground, there is no need to improve the surrounding ground, and when excavating earth and sand, expensive muddy water is not used. We have developed a method for constructing underground walls in soft ground, which is advantageous in terms of economy and shortening construction time, by making it possible to excavate without any damage, and by making the concrete surface of the constructed underground wall uniformly smooth. This is what we provide.

A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing the construction order of the underground continuous wall construction method according to the present invention, and FIG. 2 is a top view thereof. As for the construction order, first, in order to construct an underground continuous wall at a predetermined location, guide trenches 1 are installed at predetermined intervals determined by the surrounding soil water pressure and ground conditions. And according to this guide trench 1,
The box-shaped iron plate casing 2 is driven into the stable ground layer 4 deeper than the soft ground layer 3 using a vibro hammer, Monken, etc. This box-shaped iron plate casing 2 has a small cross-section of an approximately octagonal shape with flat front and rear surfaces and square end faces.By driving the casing into stable ground 4,
It is possible to use fresh water instead of expensive muddy water without causing collapse of the upper wall surface of the soft ground during excavation inside the casing. After excavating the inside of the box type iron plate casing 2 to a predetermined depth with the excavator 5 while preventing collapse of the upper wall surface in this way, a pair of joint pipes are inserted in contact with both ends of the box type iron plate casing 2. Insert 6. This joint pipe 6 is not necessarily required depending on the surrounding ground conditions, and when the joint pipe 6 is not used, the box-type iron plate casing 2 has flat front and rear surfaces and both end surfaces. Use one with a semicircular concave shape on the inside. Then, reinforced concrete 7 is placed in a space defined by the inner surface of the iron plate casing 2 and the outer surface of the joint pipe 6, and before this concrete is completely hardened, the box-shaped casing 2 and the The joint pipe 6 is pulled out using a hydraulic jack, a vibrohammer crane, etc., and a leading panel 8 having semicircular recesses formed at both ends is separated and formed. Thereafter, a pair of plate-shaped iron plates 9 are driven to a predetermined depth by the same method as the box-type casing 2 so as to sandwich the preceding panel 8, earth and sand between the plate-shaped iron plates 9 are excavated, and reinforced concrete is poured. The pair of plate-shaped iron plates 9 are pulled out using a hydraulic jack or the like, and the trailing panel 10 is formed integrally with the leading panel 8 before the concrete completely hardens. Excavation of the earth and sand between the plate-shaped iron plates 9 can be carried out without using muddy water in the same way as when excavating the inside of the casing 2. If there is a risk that the plate-shaped iron plate casing 9 will bend inward in the excavated state, the inside is excavated after driving H-shaped struts 11 between the plate-shaped iron plates 9. The reason why both ends of the preceding panel 8 are formed into semicircular recesses is to facilitate mechanical excavation during excavation.

By sequentially integrally forming the leading panel and the trailing panel in this manner, an underground continuous wall of a predetermined length is constructed. As described above, when constructing an underground continuous wall in soft ground, the present invention enables box-shaped steel plate casings to be driven into the soft ground at predetermined intervals until stable ground is reached, and the earth and sand in the steel plate casings to be removed. After excavation, reinforced concrete is placed inside the casing, and before the concrete hardens, the steel plate casing is pulled out and the preceding panels, which have semicircular recesses formed at both ends as the poured concrete hardens, are separated and formed. A pair of plate-shaped iron plates are driven in between the plates, the earth and sand between the plates is excavated, and reinforced concrete is poured between the plates, and the plate-shaped iron plates are pulled out before the concrete hardens. By constructing a continuous underground wall by forming a trailing panel integrally with a leading panel, not only does ground improvement of soft ground, which was a problem with conventional construction methods, become unnecessary, but the constructed wall surface The present invention provides a method of constructing an underground continuous wall that does not require grinding or additional hammering, improves economic efficiency, and shortens the construction period.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the construction sequence of the underground continuous wall construction method according to the present invention, and FIG. 2 is a top view thereof. The construction order is from a to d. In the figure, 1... Guide trench, 2... Box type steel plate casing, 3... Soft ground layer, 4... Stable ground layer, 5... Excavator, 6... Joint pipe, 7... Reinforced concrete, 8 ...Advanced panel, 9...Plate type iron plate casing, 10...
Trailing panel, 11... strut material.

Claims (1)

[Claims] 1. Drive box-shaped iron plate casings into soft ground at specified intervals until stable ground is reached.
After excavating the earth and sand inside the iron plate casing, reinforced concrete is placed inside the casing, and before the concrete completely hardens, the iron plate casing is pulled out and semicircular recesses are formed at both ends of the reinforced concrete. Separately form the preceding panels, drive a pair of plate-shaped iron plates so as to sandwich them between the preceding panels, excavate the earth and sand between the plate-shaped iron plates, and then pour reinforced concrete between the iron plates, A method for constructing an underground continuous wall on soft ground, characterized in that the plate-shaped iron plate is pulled out before the concrete completely hardens to form a trailing panel that is integrally connected to the leading panel.