JPH06173583A - Earth pressure balanced shield machine - Google Patents

Abstract

PURPOSE:To clarify the distribution of properties of mud and maintain the distribution uniformly by disposing a plurality of sensors for measuring mud resistance in front of a rotary cutter of a shield machine and providing additive injection holes at a plurality of points on a partition wall. CONSTITUTION:A plurality of resistance type sensors 4 are disposed at regular intervals on a cutter wing 15 in front of a rotary cutter 10. The sensor 4 comprises a resistor 42 which is erected in such a manner as to be slidable a certain distance in the rotational direction of the cutter wing 15, a displacement gauge 43 etc. Measured data from each of the sensors 4 are inputted into a central processing unit CPU, where resistance values of mud at a point where each sensor is located are computed based on predetermined calculation equations and processed to display distributing states of mud in front of a facing. Based on the distribution of properties of mud obtained, a required amount of additives is forced through the injection holes of the partition wall 12 into the mud where the additives are in short supply to obtain specified mud properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth pressure type shield machine.

[0002]

2. Description of the Related Art An earth pressure type shield excavator is a device that excavates while applying a constant pressure to the excavated soil to stabilize the cutting face.
It is equipped with an excavation mechanism for excavating the ground, a kneading mechanism for agitating the excavated soil, and a control mechanism for giving a constant restraining force to the excavated soil.The internal friction angle of the soil is large and the fluidity is poor, and The main construction targets are sand and gravel layers with high water permeability. In this type of shield machine, a cutter head is equipped with a plurality of cutter wings arranged in a radial pattern, and a kneading blade is provided along each cutter wing.
When constructing gravel ground, it is necessary to maintain a stable face. Therefore, additives (bentonite, mud making agents, bubbles, etc.) are added to the soil of the cutting face, and the soil of the cutting face is kneaded by a kneading blade that rotates with the rotation of the cutter head to provide fluidity and impermeability. This mud is filled in the mud chamber formed in the cutter head and the screw conveyor for soil discharge, and a constant mud pressure in the mud chamber is generated by the propulsive force of the shield and the throttling effect of the screw conveyor. By applying the mud pressure in the mud chamber to the face, the face is determined.

[0003]

The above-mentioned conventional earth pressure type shield technique has the following problems.

<A> Since the kneading blade is attached to the cutter wing and the rotation speed of the kneading blade cannot be changed arbitrarily, it is difficult to carry out kneading corresponding to changes in the properties of mud.

<B> Since the peripheral speeds of the kneading blades arranged along the cutter wing are different between the center of rotation and the position away from the center, the kneading effect of the kneading blades varies. As a result, the mud properties in the mud chamber become uneven.

<C> The mud property is confirmed from the mud discharged from the screw conveyor, but the distribution of the mud property in the mud chamber cannot be known.

<D> The average mud properties can be adjusted, but the mud properties in the mud chamber cannot be made uniform.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide the following earth pressure type shield machine. <a> An earth pressure type shield excavator capable of grasping the distribution of mud properties in the mud chamber. <B> An earth pressure type shield excavator that can maintain the mud properties in the mud chamber evenly. <C> An earth pressure type shield machine capable of injecting an appropriate amount of additive into an appropriate position in the mud chamber.

[0009]

The present invention comprises a rotary cutter for excavating the ground, a kneading mechanism for stirring the soil, a control mechanism for giving a constant restraining force to the soil, and the like. In an earth pressure shield machine that excavates while transmitting the mud pressure in the mud chamber to the mud on the side to stabilize the cutting face, a plurality of sensors for measuring the mud resistance are provided in front of the rotating cutter. It is a pressure shield machine.

[0010]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings.

<B> Overall Configuration FIG. 1 shows an example of a shield machine according to the present invention. The earth pressure type shield machine according to the present invention includes a rotary cutter 10 on the front surface, a mud chamber 2 between the rotary cutter 10 and a partition wall 12, and a screw conveyor 13 communicating with the mud chamber 2. The rotary cutter 10 has a plurality of cutter wings 15 arranged radially on the front surface thereof, and has discharge ports for discharging the above-mentioned additive toward the face side earth and sand at a plurality of positions. It has an opening communicating between the front surface of the and the mud chamber 2. In addition, the shield machine includes a jack 14 for excavation, an erector device for assembling a lining material (segment) 3 (not shown), and the like. The above structure is a conventional earth pressure type shield machine and a conventional structure. In the present invention, the Dotsu type shield excavator is used as a concept including earth pressure balance type, mud pressure type, closed mud type and high concentration mud pressure type shield excavator. The present invention differs from the conventional shield machine in the following points.

<B> Muddy property measuring means In this embodiment, a plurality of sensors 4 are arranged at a certain distance in front of each cutter wing 15 in order to measure the muddy property of the face. An example of this sensor 4 is shown in FIGS. The sensor 4 is a drag-type sensor, and is vertically installed in a state in which a fixed plate 41 fixed to the cutter wing 15 and a fixed sliding on the fixed plate 41 in the rotational direction of the cutter wing 15 are allowed. Plate-shaped or rod-shaped resistor 42
A displacement gauge 43 connected to the lower portion of the resistor 42, and a spring 44 disposed on the lower end of the resistor 42 at the other end of the displacement gauge 43. The displacement meter 43 measures the mutation amount of the resistor 42,
A spring 44 is a pressure member for urging the resistor 42 in the rotation direction of the rotary cutter 10, and a fluid other than the spring can be used. Explaining the principle of measurement by the sensor 4, assuming that the density of mud is ρ, the peripheral speed is v, the pressure receiving area of the resistor 42 is A, and the mounting angle of the resistor 42 is θ, the drag force D generated in the resistor 42 is It is represented by the number 1.

[Equation 1] The peripheral speed v is the distance r between the sensor 4 and the center of the cutter wing 15.
Therefore, the drag force D is expressed by the following equation 2.

[Equation 2] Therefore, in the resistor 42, the product of the pressure receiving area A of the resistor 42 and the sine value sin θ of the mounting angle θ is the cutter wing 1
5 is installed so as to be inversely proportional to the square r ² of the distance from the center. (See formula 3)

[Equation 3] By this method, when the mud properties are uniform, the resistance values generated in all the sensors 4 become equal. This drag type sensor 4 is suitable when the mud is a Newtonian fluid.

<C> Another example of sensor FIG. 5 and FIG. 6 show a shear type sensor 4a. This sensor 4
a is a state in which the pair of fixing plates 41a, 41a arranged parallel to each other and facing each other in the rotation direction of the cutter wing 15 and the facing surfaces of the respective fixing plates 41a permit sliding of the cutter wing 15 in the rotation direction. It is composed of a plate-shaped or rod-shaped resistor 42a attached in 1., a displacement gauge 43 arranged in the fixed plate 41a and connected to the resistor 42a, and a spring 44. The principle of measurement by the shear type sensor 4a will be described. The rotation of the cutter wing 15 causes the shear resistance of the mud sandwiched between the load-bearing resistors 42a, 42a constituting the sensor 4a. The resistors 42a, 42a are displaced by the resistance of the mud. The displacement meter 43 measures the amount of displacement of the resistors 42a, 42a and determines the resistance force in the following manner. The shear resistance τ of the resistor 42a is represented by the product of clay η of mud and shear strain rate γ. (See formula 4)

[Equation 4] The shear strain rate γ is a value obtained by dividing the peripheral speed v at the mounting position of the sensor 4a by the distance d between the resistors 42a and 42a.
(Equation 5)

[Equation 5] Since the peripheral speed v is proportional to the distance between the center of the sensor 4a and the center of the cutter wing 15, the shear resistance force τ of mud is expressed by the following equation 6.

[Equation 6] Therefore, each sensor 4a has two resistors 42a, 42a in proportion to the distance from the rotation center of the cutter wing 15.
Are arranged such that the distance d between them becomes large. (See formula 7)

[Equation 7] With this method, it is possible to apply the same shear strain rate γ to the sensor 4a at any position, and when the mud property is uniform, the shear resistance value generated at any sensor 4a becomes equal. This drag type sensor 4 is suitable when the mud is a non-Newtonian fluid.

<D> Data Processing Method As shown in FIG. 1, the measurement data of each sensor 4 (4a) is input to the central processing unit CPU, and the central processing unit CPU uses each of the sensors 4 based on the above calculation formula. The resistance value of the mud at the position (4a) is calculated, and the distribution of the mud on the front face of the face is displayed based on the data at these positions. The method of analyzing the data from each sensor 4 (4a) and the method of displaying the distribution of mud properties are the same as the conventional one.

<E> Additive Injecting Means In the shield machine of the present invention, a plurality of injection holes are radially provided in the partition wall 12 as shown in FIG. 2 so that the additive can be injected at any position in the mud chamber 2. 16 are open.

<F> Independent stirring blades Further, in the shield machine of the present invention, a plurality of independent stirring blades 17 are concentrically provided on the partition wall 12 so as to stir an arbitrary range in the mud chamber 2. The independent stirring blade 17 may be omitted.

[0017]

Next, the operation of the shield machine will be described.

<A> Excavation As shown in FIG. 1, the rotary cutter 10 is rotated in a predetermined direction to excavate the face, the excavated earth and sand is taken into the mud chamber 2, and the mud in the mud chamber 2 is propelled by the shield. Pressurization to a constant pressure by force or the throttling effect of the screw conveyor 13 is the same as in the prior art.

<B> Grasp of mud properties The respective sensors 4 (4a) provided on the cutter wing 15 on the front surface of the rotary cutter 10 measure the resistance value of the cutting soil. The measured data is sent to a stationary system and subjected to data processing to obtain a distribution of mud properties in the face mud chamber 2. The data obtained by each sensor 4 (4a) is information on the mud property of the cutting face, but since the front face of the rotary cutter 10 and the mud chamber 2 are in communication with each other, the cutting mud and the mud in the mud chamber 2 are in communication. Is substantially the same as the blur condition, so there is no special problem even if the mud information on the face side is treated as the mud information in the mud chamber 2.

<C> Additive Injection Based on the distribution of the mud properties, the additive is injected into the insufficient portion of the additive through the optional injection hole 16 shown in FIG. This makes it possible to obtain a desired mud property by injecting the necessary minimum amount of additive.

<D> Partial agitation When the shield machine is equipped with a partial agitation blade 17, the partial agitation blade 17 located near the additive injection position.
Rotate for a certain time to partially stir the mud. In addition, all the partial stirring blades 17 may be always movable.

[0022]

[Other application examples] The present invention is a material having a relatively high viscosity, which is prepared by kneading a plurality of materials in addition to mud (ground improvement agent, backfill material, priority material, ready-mixed concrete, food, oil and fat, etc.)
By incorporating a sensor or an injection hole in a stirring tank or a storage tank for kneading, it is possible to obtain a kneaded product having uniform properties.

[0023]

Since the present invention is as described above, the following effects can be obtained.

<a> It is possible to know the distribution of mud properties in the face mud chamber.

<B> It is possible to keep the mud properties in the face mud chamber uniform. In particular, with a large-section shield or twin shield, it is difficult to maintain the uniformity of mud, so the effect of the invention is great.

<C> Since an appropriate amount of additive can be injected through the injection hole formed in the partition wall according to the distribution of the mud properties,
The additive injection work can be carried out efficiently and economically.

[Brief description of drawings]

FIG. 1 is an explanatory view of a shield machine according to the present invention.

2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a perspective view of a drag-type sensor.

FIG. 4 is a sectional view of a drag-type sensor.

FIG. 5 is a perspective view of a shear type sensor.

FIG. 6 is a plan view of a shear type sensor.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yuichi Higuchi 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Taisei Corporation

Claims (3)

[Claims] 1. A rotary cutter for excavating the ground, a kneading mechanism for stirring the excavated soil, a control mechanism for giving a constant restraining force to the excavated soil, etc., and the mud pressure in the mud chamber in the mud on the cutting face side. An earth pressure shield excavator that is equipped with a plurality of sensors for measuring mud resistance in front of a rotating cutter in an earth pressure shield excavator that travels while stabilizing the face. 2. The earth pressure type shield machine according to claim 1, wherein an injection hole for injecting an additive is opened in a partition wall defining the mud chamber. 3. The earth pressure type shield excavator according to claim 1, wherein a plurality of agitating blades for partially agitating the mud chamber are provided on a partition wall defining the mud chamber. .