JPH03217515A - Construction of sheathing and cut-off wall - Google Patents

Abstract

PURPOSE:To make execution of work easy by a method wherein vertical holes are drilled into the ground, then mud columns are constructed with bentonite milk poured therein and agitated there and after erecting underground piles, soil mortar columns are constructed with cement milk poured therein and agitated there. CONSTITUTION:Vertical holes 1, 2, 3 are drilled into the ground with a triple- shafted earth auger. Mud columns are then constructed in the vertical holes 1, 2, 3 with slow-hardening bentonite milk injected into the holes and agitated there. Underground piles 4 are erected in every other or in every third vertical holes 1, 2, 3. Installation intervals of the underground piles 4 depend on the scale of a sheathing and cut-off wall to be constructed. In the case where the ground is hard, the installation intervals can be extended so that the materials can be saved, requiring less piles. Mortar piles 5 are then constructed between the underground piles 4 with materials containing cement milk injected with a boring machine by high-pressure jet agitation method. Thereby water stop works can be executed without fail.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of constructing an earth retaining water-stop wall.

(Prior Art and Problems to Be Solved) Conventionally, the so-called SMW construction method using a triaxial drill is generally known as a construction method for earth retaining and water stop walls.

This type of construction method uses a triaxial auger to drill a vertical hole in the ground, then injects and stirs bentonite cement milk into the vertical hole to create a soil mortar.
An earth retaining wall is constructed continuously using underground piles made of steel or other materials.

By the way, if this construction method is attempted in a place where there are obstacles above, such as under a bridge girder, it will be difficult to use a large three-shaft auger.

For this reason, it is necessary to use a small three-shaft auger machine, and if the retaining wall is deep, it is necessary to add more augers depending on the depth of the retaining wall. The work must be carried out at night when there is no train traffic, so
Work efficiency is significantly reduced, and construction of a single section often takes several days.

However, because bentonite cement milk, which hardens relatively quickly, is used in this construction, it may become impossible to drive underground piles if the construction lasts several days.

This invention was proposed in order to solve the above-mentioned conventional problems, and it is possible to install underground piles such as H-section steel without M even after several days have passed after producing hentonite milk in a vertical hole in the ground. The purpose of the present invention is to provide a construction method for an earth-retaining water-stop wall that can be built up.

[Means to solve problems]

This invention relates to a method for constructing an earth retaining water cutoff wall, in which a vertical hole is drilled in the ground, then hentonite milk is poured into the vertical hole and stirred to construct a mud pillar, and then a mud column is constructed in the vertical hole. The above object is achieved by driving a plurality of underground piles into the hole, then pouring and stirring cement milk between the underground piles and constructing a soil mortar column.

[Example] The present invention will be described below based on an illustrative example.

: Holes 1, 2, and 2 are drilled into the ground by the shaft auger as shown in the figure.
Drill holes 3 in this order.

In such cases, bentonite milk, which hardens relatively slowly, is used as the injection material for drilling and mixing.

The curing time of the hentonite milk shall be adjusted by appropriately changing the mixture of materials according to the construction schedule.

After drilling of the vertical holes 3 is completed, underground piles 4, 4 are driven into every other or every two vertical holes 1, 2, and 3.

In principle, H-section steel is used for the underground pile 4, but I-section steel may also be used.

In addition, the installation interval of the underground piles 4 varies depending on the scale of the earth retaining water cutoff wall, but in the case of deep and soft ground, the strength is increased by narrowing the installation interval and increasing the number of installations, and conversely, in the case of shallow and hard ground In some cases, it is possible to save material by widening the installation interval and making the installation space a little smaller.

After the installation of the underground piles 4 is completed, mortar is placed between the underground piles 4 and 4 installed in the introduction holes 1, 2, and 3 using a Bonong machine using a high-pressure jet stirring method using cement milk as the injection material. Construct resistor 5.

The mortar shaft 5 is constructed so as to surely reach the grooves 4a, 4a of the left and right underground piles 4,4.

Thereafter, underground walls will be constructed continuously using the same method.

Note that, in addition to cement milk, a chemical injection material can be used as the injection material.

〔Effect of the invention〕

Since the present invention has the above configuration, it has the following effects.

■ The construction method of the earth retaining water stop wall according to this invention is basically the same as the conventional SMW construction method, but the method of injecting and stirring the fast-hardening cement milk into the vertical hole is C. Instead, bentonite milk hardens relatively slowly, so underground piles can be easily driven into vertical holes even after several days have passed.

In addition, after installing the underground piles, soil mortar columns are continuously constructed using the high-pressure jet PA stirring method using cement milk between the H-shaped holes, making it possible to reliably perform water-stop construction.

Therefore, the construction can be easily carried out even in places such as under a guard where construction must be carried out over several days.

[Brief explanation of drawings]

The figure is a plan view showing a method of constructing an earth retaining water stop wall according to the present invention. 1, 2. 3...Fir hole, 4...Underground pile, 5...Mortar pile.

Claims (1)

[Claims] (1) Drill a vertical hole in the ground, then inject and stir bentonite milk into the vertical hole to construct a mud column, and then drive a plurality of underground piles into the vertical hole, A method for constructing an earth retaining and water-stopping wall, which comprises subsequently injecting and stirring cement milk between the underground piles and constructing soil mortar columns.