JP2960712B1 - Propulsion method - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: In a propulsion construction method, an installation interval of a perforated pipe for injecting a lubricant into a tail void into a propulsion pipe is set to an economically optimum interval, and an ultra-long distance capable of maintaining an effect of reducing frictional resistance during propulsion. Provides a propulsion method. SOLUTION: An excavator 2 having an overcut function, a propulsion pipe 3 and a perforated pipe 4 following the excavator are propelled into the ground, and a tail void 6 is formed around the propulsion pipe 3 by excavation by the excavator 2, and In the propulsion method in which the tail void lubricant is injected from each lubricant injection hole into the tail void 6 from the lubricant injection hole of the pipe 4, the relationship between the properties of the soil and the resistance generated during the propulsion of the propulsion pipe is determined. The installation interval of the perforated pipe 4 to the propulsion pipe 3 is set for each property of the propulsion pipe 3, and the distribution of the soil properties over the entire length of the ground to be constructed is grasped in advance in the construction of the propulsion method. The installation interval of the perforated pipe 4 is calculated to minimize the number of perforated pipes 4 to be installed to a necessary minimum, thereby improving the economy of construction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a propulsion method, and more particularly, to a semi-shield method for constructing a pipeline in the ground.
The present invention relates to a propulsion method that enables ultra-long distance propulsion at low cost by reducing frictional resistance generated during propulsion.

[0002]

2. Description of the Related Art A semi-shield method has been adopted as a propulsion method for constructing a pipeline for storing sewage facilities and various underground objects underground.

[0003] In the semi-shield method, a jack and a reaction force support plate are installed in a starting shaft, and a semi-shield machine and a propulsion pipe, which is a fume tube, are pushed into the ground by a jack and excavated. The excavation by the machine and the extension and pushing of the propulsion pipe are repeated, and the excavator is taken out to the reaching shaft, thereby constructing a pipeline in the ground.

[0004] In the semi-shield method, for example, in order to realize ultra-long-distance propulsion with a span of 1000 m class, it is most important to reduce frictional resistance generated between the propulsion pipe and the ground. The straight line in FIG. 7 shows the relationship between the progress of propulsion and the frictional resistance in soil with a substantially uniform range of propulsion length,
It can be seen that the frictional resistance increases in proportion to the progress of the propulsion length, and that a longer propulsion length requires a larger propulsion force.

The conventional method of reducing the frictional resistance between the propulsion pipe and the ground in the semi-shield construction method is to excavate about 50 mm by the excavator when propelling the shield excavator and the subsequent propulsion pipe into the ground. In addition to excavating the tail void which is an overcut portion on the outer periphery of the propulsion pipe, forming a mud film layer on the outer periphery of the tail void in the excavation part, incorporating a concrete pipe and a perforated pipe made of steel pipe in the middle of the propulsion pipe. The tail void pressurizing agent A supplied from the injection hole provided in the perforated pipe is injected into the tail void, and the tail void is secured by the lubricating tail void pressurizing agent to reduce the frictional resistance between the propulsion pipe and the ground during propulsion. I try to plan.

[0006] In the injection of the tail void pressurizing agent into the tail void, in order to more effectively reduce the frictional resistance, the arrangement of the perforated pipe incorporated in the middle of the propulsion pipe is set narrow, and the tail void pressing agent is injected into the tail void. It is conceivable to increase the amount.

Here, in order to secure the tail void by the tail void pressurizing agent, as shown in FIG. 5, a well-known mud film or mud is formed on the entire periphery of the tail void 6 and formed on the ground excavation surface. Generation and maintenance of the film layer B is essential. The mud film or mud film layer B serves to prevent the tail void pressurizing agent A under pressure from escaping into the soil of the ground. The above-mentioned mud film or mud film layer B is formed by mixing the mud film forming member and the excavated soil to be supplied to the excavated portion when excavating by the shield excavator,
The mud film or mud film layer B is formed at a portion where the tail void pressurizing agent contacts the ground.

[0008]

Incidentally, in securing the tail void, there is a close relationship between the nature of the soil and the formation of a mud film or a mud film layer (hereinafter referred to as a mud film layer B). Or anhydrous layer,
The generation of the mud film layer B is inefficient, and it takes a long time to generate the mud film layer B. For this reason, the tail void pressurizing agent A permeates into the soil of the ground, and it is very difficult to secure the tail void 6. It is.

On the other hand, when the soil is a silt layer or a clay layer, the formation of the mud film layer B is efficient, and the penetration of the tail void pressurizing agent A into the ground is small. Good. However, irrespective of such changes in soil properties, the conventional method of arranging perforated pipes is as follows.
Since the intervals were constant or appropriate, uncertainties were extremely high, such as relying on the feelings of craftsmen or planning excessive use.Therefore, the proportion between the outer peripheral surface of the propulsion pipe and the ground was proportional to the propulsion length. At present, it has been said that the original purpose to greatly reduce the frictional resistance, which has been considered to be generated, is that the effect cannot be sufficiently obtained.

Further, the mud film layer B generated by the tail void pressurizing agent A breaks down due to permeation into the ground or deteriorates with time, making it difficult to maintain the mud film layer B for a long time. It penetrates into the ground, making it difficult to secure the tail void 6 in the case of a long distance, increasing the frictional resistance, making propulsion impossible, and making long distance propulsion impossible.

Further, in the injection of the tail void pressurizing agent A into the tail void 6, in order to more effectively reduce the frictional resistance, the interval between the perforated pipes to be incorporated in the middle of the propulsion pipe is set to, for example, 5 m or 10 m. It is conceivable to increase the injection amount of the tail void pressurizing agent A into the tail void by setting the width as narrow as possible, but by spreading the tail void pressurizing agent A over the entire outer periphery of the propulsion pipe, the effect of reducing the frictional resistance can be obtained. However, the construction cost is extremely high.

By the way, the cost of assembling a perforated pipe is high, about 500,000 to 2,000,000 yen per pipe, depending on the diameter of the pipe. Therefore, the use of a large number of these pipes increases the cost and significantly impairs the economic efficiency.

Therefore, an object of the present invention is to focus on the point that the formation of the mud film layer shows a different degree of formation with respect to the properties of the soil soil, and in the construction of the propulsion method, the distribution of the soil properties over the entire length of the ground to be constructed. In advance, and determine the relationship between the properties of the soil and the resistance generated when the propulsion pipe is propelled,
Based on this, the arrangement interval of the perforated pipes to be used is determined to be the optimum interval, and the generation and maintenance of the mud film layer can be reliably performed, thereby minimizing the interval between the perforated pipes incorporated in the propulsion pipe. It is an object of the present invention to provide a propulsion method capable of effectively reducing frictional resistance while maintaining the same and performing ultra-long distance propulsion at low cost.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to claim 1 is to excavate an excavator having an overcut function, and a propulsion pipe and a perforated pipe following the excavator, to excavate the excavator. A tail void is formed around the propulsion pipe by excavation with a machine, a plurality of lubricant injection holes are arranged side by side in the circumferential direction of the perforated pipe to be propelled underground, and the tail void lubricant is injected from each injection hole into the tail void by pressure. In the propulsion method, the relationship between the properties of the soil and the resistance generated during the propulsion of the propulsion pipe was determined, and from this resistance value, the spacing between the perforated pipes and the propulsion pipe was set for each property of the soil. The distribution of the soil properties over the entire length of the ground to be constructed is grasped in advance, the installation interval of the perforated pipe to the propulsion pipe is calculated for each grasped property of the soil, and the propulsion pipe over the entire length of the ground is calculated from the calculated value. Against is obtained by averaging values of the embedded interval of the porous tube, it employs a configuration that sets the incorporation of porous pipe for propulsion tube spacing of the mean values.

According to a second aspect of the present invention, in the first aspect of the present invention, a tail void is formed around the propulsion pipe by over-digging by the excavator, and a mud film layer generated in the excavation portion and a porous film are formed around the tail void. This embodiment adopts a configuration in which a mud film layer having a double structure composed of a mud film layer formed by a tail void lubricant pressed into a tail void from a lubricant injection hole of a pipe is formed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a semi-shielding method, in which an excavator 2 having an overcut function, a propulsion pipe 3 connected to a rear part of a casing 2a of the excavator 2, and a propulsion are introduced from a starting shaft 1 into the ground. The perforated pipe 4 to be incorporated into the pipe 3 at a predetermined interval is penetrated into the ground by pushing with the jack 5 and excavating by the cutter 2 b of the excavator 2.
A tail void 6 of about 0 mm is formed, and a lubricant A1 is fed from a lubricant supply device 7 on the ground to a lubricant supply pipe 8, and the lubricant A1 is simultaneously injected into the tail void 6 from each lubricant injection hole 9 of the perforated pipe 4. 6 to reduce the resistance of propulsion.

FIGS. 2 and 3 show the cross-sectional structure of the perforated pipe 4 to be incorporated between the propulsion pipes 3 in a connected state. A lubricant injection hole 9 is provided on the peripheral wall at predetermined intervals so as to penetrate inside and outside. 4 is connected to each lubricant injection hole 9, and a lubricant supply pipe 8 is connected to the distribution pipe 10 via an electromagnetic valve 11. The lubricant A1 supplied from the lubricant supply device 7 is simultaneously injected into the tail void 6 from each lubricant injection hole 9.

Here, the lubricant A1 is mainly composed of sodium polyacrylate and a spherical water-absorbing swelling agent, which is a white powdery food additive and a light yellow sphere sanitary article. Is used as a fluid having a transparent spherical viscous material of PH7.

This lubricant A1 exerts a clogging effect between soil particles without any pollution to the human body, animals and plants, and the earth, instantaneously forms a mud film layer on the outer peripheral surface of the tail void 6, and reduces the hydraulic pressure. There is a function to keep.

By using the above-mentioned lubricant A1, FIG.
As shown in the figure, at the time of excavation by the shield excavator, the mud film layer B formed by mixing the mud film forming member supplied to the excavated portion with the excavated soil has a tail void 6.
The lubricant A1 press-fitted into the mud film B forms a new mud film layer B1 inside the mud film layer B.
Accordingly, the mud film layer has two layers, and even if the outer mud film layer B deteriorates with time, the inner mud film layer B1 keeps the lubricant A1 pressed into the tail void 6 from penetrating into the ground. In this case, the hydraulic pressure of the lubricant A1 is maintained for a long time over the entire length of the propulsion, and the long-term reduction of the propulsion resistance enables, for example, 1000 m-class ultra-long-distance propulsion.

According to the present invention, in the construction of the semi-shielding method as described above, the arrangement interval of the perforated pipes 4 incorporated in a connected state between the propulsion pipes 3 is most suitable for keeping the tail voids 6 stable for a long period of time. In order to set the interval, the relationship between the properties of the soil and the resistance value generated during the propulsion of the propulsion pipe is determined, and from this resistance value, the installation interval of the perforated pipe 4 with respect to the propulsion pipe 3 is set for each soil property, and the total length of the ground to be constructed Of the soil properties of the propulsion pipe 3 with respect to the propulsion pipe 3 is calculated for each of the grasped soil properties, and the calculated value is used to determine the installation interval of the perforated pipe 4 with respect to the propulsion pipe over the entire length of the ground. An average value is obtained, the incorporation of the perforated pipe 4 into the propulsion pipe 3 is set at the interval of the average value, and two mud film layers are formed.

The inventor of the present invention has conducted intensive studies and found that the degree of formation of the mud film B responsible for maintaining the hydraulic pressure of the tail void 6 has a close relationship with the groundwater pressure and soil properties near the passage of the propulsion pipe 3. It was found that each of them had a different degree of formation depending on soil conditions and the like.

Properties of soil particle size distribution (soil number to
) And the degree of formation of the mud film layer in the propulsion method are shown in Table 1.

[0025]

[Table 1]

Here, for example, FIG. 6 shows the relationship between the outer peripheral surface resistance of the propulsion pipe 3 and the installation interval of the perforated pipe 4 in the propulsion method in the soil of the soil number shown in Table 1. Since the soil of this soil number has groundwater and a well-balanced particle size distribution (for example, silt content 30%, clay content 30%, sand content 30%), the formation of the mud film layer becomes extremely favorable. When the perforated pipes 4 are arranged at intervals of 50 m, it has been found that the tail void lubricant A1 can be supplied evenly to the entire peripheral surface of the propulsion pipe 3 most efficiently. I was able to fully demonstrate my strength. The same result is obtained even when the perforated pipes 4 are arranged at intervals of 45 m. When the perforated pipes 4 exceed 55 m, the retention of the tail voids is affected. Therefore, the economical optimal interval of the perforated pipes 4 is determined to be 50 m.

The optimum intervals shown in Table 1 were determined for other soils in the same manner.

Table 2 shows the optimum intervals for assembling the perforated pipes 4 into the propulsion pipes 3 based on the relationship between the properties of the soil and the resistance of the outer peripheral surface in the soils of each soil number from Table 1 onwards.

[0029]

[Table 2]

According to the present invention, in the construction of the propulsion method, groundwater and soil properties at the construction site are investigated in advance, and the propulsion is performed for each soil property based on the relationship between the soil properties and the resistance value generated when the propulsion pipe 3 is propelled. The installation interval of the perforated pipe 4 with respect to the pipe 3 is set, the distribution of the soil properties over the entire length of the ground to be constructed is grasped in advance, and the installation interval of the perforated pipe 4 with respect to the propulsion pipe 3 is calculated for each grasped soil property. From the calculated values, the average value of the installation interval of the perforated pipe 4 to the propulsion pipe 3 over the entire length of the ground is determined, and the installation of the perforated pipe to the propulsion pipe 3 is set to the interval of this average value.

As a result, as shown in FIG. 7, the securing of the tail void 6 and the reduction of the resistance by maintaining the pressure can be averaged with respect to the total resistance value over the entire length of the ground in the construction of the propulsion method. The generation of frictional resistance is substantially constant with the progress of the long distance, enabling the realization of ultra-long-distance propulsion, and by setting the interval of assembling the perforated tubes 4 to the minimum optimum interval, the number of perforated tubes 4 can be reduced. Is reduced to the minimum necessary to reduce the frictional resistance, and the economic efficiency can be greatly improved.

[0032]

As described above, according to the first aspect of the present invention, in the propulsion method using an excavator having an overcut function, the relationship between the properties of the soil at the construction portion and the resistance value generated during the propulsion of the propulsion pipe is determined. From this resistance value, set the installation interval of the perforated pipe to the propulsion pipe for each soil property based on this resistance value, and in advance of the construction method of the propulsion method, grasp the distribution of soil properties over the entire length of the ground to be constructed, and grasp the properties of each soil property grasped The installation interval of the perforated pipe to the propulsion pipe is calculated every time, and the average value of the installation interval of the perforated pipe to the propulsion pipe over the entire length of the ground is calculated from the calculated value. Because it was set, the securing of the tail void and the reduction of resistance by pressure holding can be averaged with respect to the total resistance value over the entire length of the ground in the construction of the propulsion method, By setting the minimum interval between bored pipes, the economical efficiency can be greatly improved, and the tail void lubricant can maintain the effect of reducing friction during propulsion, enabling ultra-long-distance propulsion. it can.

According to the second aspect of the present invention, a tail void is formed around the propulsion pipe by the excavation by the excavator, and a mud film layer generated at the excavation portion and a lubricant for the perforated pipe are formed around the tail void. Since a mud film layer with a double structure consisting of a mud film layer generated by the tail void lubricant pressed into the tail void from the injection hole is formed, the tail void lubricant is secured around the propulsion pipe for a long time over the entire length during propulsion. Becomes possible,
Ultra-long-distance propulsion becomes feasible by reducing drag during propulsion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a construction state of a propulsion method according to the present invention.

FIG. 2 is a longitudinal sectional view of a perforated tube used in the above.

FIG. 3 is a perspective view of a perforated tube.

FIG. 4 is an explanatory view showing the formation of a mud film layer of a tail void.

FIG. 5 is an explanatory view showing formation of a mud film layer of a tail void in a conventional propulsion method.

FIG. 6 is an explanatory diagram showing the relationship between the interval between the perforated tubes and the frictional resistance of the outer periphery of the propulsion tube.

FIG. 7 is an explanatory view showing generation of frictional resistance in a conventional propulsion method and generation of frictional resistance according to the present invention.

[Explanation of symbols]

 2 Excavator 3 Propulsion pipe 4 Perforated pipe 6 Tail void A1 Tail void lubricant B, B1 Mud film layer

Claims (2)

(57) [Claims] 1. An excavator having an overcut function, and a propulsion pipe and a perforated pipe following the excavator are propelled into the ground, and a tail void is formed around the propulsion pipe by extra excavation by the excavator, and the perforated water is propelled into the ground. A plurality of lubricant injection holes are arranged side by side in the circumferential direction of the pipe, and in the propulsion construction method in which the tail void lubricant is injected under pressure from each injection hole into the tail void,
The relationship between the properties of the soil and the resistance generated during the propulsion of the propulsion pipe is determined.From this resistance, the spacing between the perforated pipes and the propulsion pipe is set for each property of the soil. The distribution of soil properties is grasped in advance, the installation interval of the perforated pipe to the propulsion pipe is calculated for each grasped soil property, and the average value of the installation interval of the perforated pipe to the propulsion pipe over the entire length of the ground is calculated from the calculated value. A propulsion method, wherein the incorporation of a perforated pipe into the propulsion pipe is set at the interval of this average value. 2. A tail void is formed around the propulsion pipe by an excavation by an excavator, and a mud film layer formed in the excavation portion and a tail void lubricant press-fit into the tail void from a lubricant injection hole of the perforated pipe are formed on the outer periphery of the tail void. 2. The propulsion method according to claim 1, wherein a mud film layer having a double structure including a mud film layer generated in the step (a) is formed.