JPH03110294A - Sludge-pressure shield construction work - Google Patents

Abstract

PURPOSE:To permit shield-excavation of aquifer and sandy layer by a method in which excavated soil by cutters in the ground having mud-water films is discharged pneumatically while pressurizing the front facing of partitioned walls of the tip of an open-type shield excavator. CONSTITUTION:The tip of an open-type shield excavator 1 is partitioned by partition walls 7, and while pressurizing the facing of the ground 10 by compressed air from an air supply tube 6, mud water M is sprayed from a nozzle 4 on the tip of a cutter 2 onto the facing of the ground 10 to form a mud water film 5 on the facing. Under a condition that the leakage of compressed air A from a sandy layer is prevented, the facing of the ground 10 is excavated by the cutter 2, and the excavated soil S is discharged to the rear T from a soil discharge tube 9 turning by a tube turner 8 by utilizing the compressed air. Large gravels are crushed by the double door of the partition wall 7 and discharged. The degradation of the facing can thus be prevented economically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mud pressure shield construction method mainly suitable for excavating aquifer sand and gravel layers.

[Conventional technology]

Conventionally, to excavate an aquifer gravel layer with a shield, there are two methods: using an open shield machine, excavating the face mechanically or by hand while pressurizing the face with compressed air, and using a closed shield machine. The mud pressurized shield method, in which excavation is performed while stabilizing the face using the pressure of mud, is generally used.

In the above-mentioned method of excavating while pressurizing using an open shield machine, since the ground to be excavated is a gravel layer, there is a problem that the pressurized air escapes and the face collapses.
In order to deal with this problem, chemical liquid injection is carried out, but in this case, there are problems in that the cost is extremely high and the chemical liquid spreads to the surrounding area and causes pollution.

In addition, the mud water pressurized shield construction method has a problem in that when large gravel appears, the shield machine is of a closed type, making it impossible to remove the soil.

[Problem to be solved by the invention]

The present invention was made in order to solve the above-mentioned conventional problems, and the present invention prevents the air pressurized at the face from leaking from the gravel layer, and also enables easy handling even when large gravel appears. The problem to be solved was to provide an economical shield construction method suitable for layer excavation.

[Means to solve the problem]

As a means to solve the above problems, the mud pressure air shield construction method of the present invention partitions the tip of an open type shield machine with a partition wall, and pressurizes the face in front of the partition wall with compressed air sent from an air pipe. However, when spraying mud from the tip of the cutter, the mud material sprayed from the nozzle forms a mud film on the face to prevent pressurized compressed air from leaking from the gravel layer of the face, and the cutter excavates the ground. It is characterized by using pressurized air to remove the earth and sand from the excavated gravel layer from the mud removal pipe. Excavation is carried out under pressure.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of excavation work using the mud pressure shield method of the present invention will be described below with reference to the drawings.

First, in excavation work using this shield method, an open shield machine 1 is used to excavate while using pressurized air in the case of a gravel layer with a lot of groundwater such as spring water.

Therefore, the tip of the shield m1 is partitioned with a partition wall 7, and while compressed air A sent from the air pipe 6 pressurizes the face of the ground 10, the muddy water spray provided at the tip of the cutter 2 is sprayed from the nozzle 4. Material M is sprayed onto the face of the earth 10 to form a muddy water film 5 on the face, and compressed air A is
prevents leakage from the gravel layer of the face.

In this case, the slurry material M is a mixture of water, clay, bentonite, thickener, etc., and the mixing ratio thereof is determined as appropriate depending on the condition of the ground lO. shall be.

Next, as described above, the face of the ground 10 was excavated with the cutter 2 in a state where the compressed air A pressurized by the muddy water film 5 formed by the muddy water material M did not leak from the gravel layer of the ground 10. Sediment S in the gravel layer is compressed from the face side indicated by P, indicated by T, through the air pressure difference through the mud removal pipe 9, which is rotated by the mud removal pipe turning device 8, using the pressure of the compressed air A. The soil is discharged to the rear part of the tank under atmospheric pressure.

On the other hand, when there are large gravels on the face of the earth 10, the partition wall 7 is made into a double door so that personnel can enter the face side and break the large gravels into small pieces and discharge them.

The cutter 2 in the figure is rotated and rotated by a cutter rotation drive device 3.

Further, this shield machine 1 is provided with a propulsion jack (not shown) at the rear, and each time the shield machine 1 is excavated, the shield machine 1 is advanced by the excavated bone, and the segments are set in the meantime.

〔Effect of the invention〕

According to the mud pressure shield construction method of the present invention explained above,
Since a muddy water film is created on the face using the muddy water material, pressurized air will not leak, and the collapse of the face can be economically prevented.

Furthermore, even if large debris appears, the use of an open-type shield machine has the advantage that it can be dealt with more easily than a closed-type machine.

[Brief explanation of drawings]

The figure is a side sectional view showing an embodiment of excavation work using the mud pressure air shield method of the present invention. DESCRIPTION OF SYMBOLS 1... Shield machine, 2... Cutter, 4... Nozzle for spraying muddy water, 5... Mud water film, 6... Air pipe, 7...
... Bulkhead, 9... Sludge drainage pipe, 10... Earth, A...
Compressed air, M...muddy water material, S...earth and sand.

Claims (1)

[Claims] Using compressed air to pressurize the face in front of the bulkhead that partitions the tip of an open shield machine, the cutter excavates earth and sand that has formed a muddy water film on the face using muddy material sprayed from the cutter tip. This is a mud pressure shield construction method in which earth is removed using mud.