JPH0237453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of constructing an underground structure.

In general, the construction of an underground structure involves building a retaining wall, then excavating the ground while supporting the retaining wall with earth anchors, struts, etc., and constructing the structure. There are the following problems.

When excavating at great depths, the lateral pressure is large, requiring a rigid retaining wall and a large cross-section of the strut. In addition, problems such as the water-stopping properties of the retaining wall and heaving at the bottom of the cut occur.

The repeated excavation work and temporary pile-up work makes the construction work complicated and takes a long time.

Much of the work is done underground, and materials are transported underground.
There will be more transport.

Reducing the groundwater level in the surrounding ground will cause pollution problems such as surrounding ground subsidence.

The present invention was proposed to solve these problems, and involves excavating the earth and sand within the retaining wall built underground, and then pouring underwater concrete at the bottom of the excavation hole to form a bottom plate. Then, the lower end of the box structure is floated in the excavation hole, and the upper box structure is successively placed on top of the box while water is poured into the box and maintained at a required level. They are joined together to form a box structure, and after the structure is lowered to the bottom of the excavation hole, mortar is injected between the bottom of the lower end box part and the bottom plate to form the box structure. This relates to a method for constructing an underground structure, which is characterized by seating the box structure and then pouring concrete between the box structure and the retaining wall.

In the present invention, after excavating the earth and sand within the retaining wall built underground, underwater concrete is poured at the bottom of the excavation hole to form a bottom base, and then the lower end of the box structure is placed in the excavation hole. Floating the box part, pouring water into the lower end of the box part, and adjusting the level so that the working space within the box part always occupies a position where it is easy to work, sequentially connect the upper box structure part to the top of the floating part. By doing so, the box structure is constructed and allowed to settle near the bottom of the borehole, and then mortar is injected between the concrete base at the bottom of the borehole and the bottom of the lower end box part. By this, the box is firmly seated and anchored at the bottom of the excavation hole, and then concrete is poured between the retaining wall and the outer circumferential surface of the box structure to form a box structure. is integrated with the retaining wall to increase rigidity.

In this way, in the underground structure according to the present invention, the level of the box in the excavated hole in the retaining wall is adjusted so that the work space is located near the ground surface, and the structure is lowered while simultaneously connecting the upper structure. Therefore, there is much work on the ground, less movement of materials, improved work safety, mechanization of construction, shortened construction period, reduced construction costs, and enabled deep excavation. The present invention has many advantages.

The present invention will be described below with reference to the illustrated embodiments.

A retaining wall 1 having a desired cross-sectional shape is constructed underground. Next, the earth and sand in the area surrounded by the retaining wall 1 is excavated underwater. At this time, the water level within the retaining wall 1 is adjusted so as to maintain a balance with the lateral pressure. The excavated hole 2 thus formed in the retaining wall 1
Concrete base plate 3 is constructed by pouring underwater concrete at the bottom. Next, a lower end box part a made of steel plate or concrete is floated in the excavated hole 2. At this time, the box part a is held at a level that is easier to work on than the ground surface using a level holding jig b, and the underground beam c is constructed inside the box part a. (See Figure 1) Next, the water in the excavation hole 2 is injected into the lower end box part a through an appropriate water injection means such as a pump d, and the top end of the box part a is worked near the ground surface. lower it to an easy level. (See Figure 2) Next, a column e is installed on the top of the underground beam c and the box part a.
While constructing the box structure A by joining the upper box structure consisting of the beam e′ and the upper case surrounding wall a′, water injection into the same structure, level adjustment, and the above-mentioned pillars, beams, and upper case surrounding wall. Repeat the joining work. (See Figure 3) When the lower end box part a has settled to a predetermined depth, the slime at the bottom of the box part a is treated by spraying pressurized water, etc., and then the lower part of the box part a and the concrete bottom are treated. Mortar f is injected between the container structure A and the carrier 3 to allow the box structure A to bottom out. After that, a reinforcing bar cage is inserted into the gap between the retaining wall 1 and the peripheral wall of the box structure A, and then underwater concrete g is poured to integrate the retaining wall 1 and the box structure A. , increase rigidity. (See Figure 4) Next, after the poured concrete is cured, the water in the box structure is drained, and if necessary, inner wrap concrete is poured to complete the entire process.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of drawings]

1 to 4 are vertical cross-sectional views showing the steps of an embodiment of the underground structure construction method according to the present invention. a...lower box, c...underground beam, e...column,
e′... Beam, f... Mortar, g... Underwater concrete, 1... Mounting wall, 2... Excavation hole, 3... Concrete base, A... Box structure.

Claims (1)

[Claims] 1. Excavating the earth and sand within the retaining wall built underground, then placing underwater concrete at the bottom of the excavation hole to form a bottom plate, and then placing the lower end of the box structure in the excavation hole. Then, while water is injected into the box part to maintain it at a required level, the upper box structure part is successively joined on top of the box part to form a box structure, and the structure is then excavated. After settling to the bottom of the hole, mortar is injected between the bottom of the lower end box part and the bottom plate to seat the box structure, and then a mortar is placed between the box structure and the retaining wall. A method of constructing an underground structure characterized by pouring concrete.