JP2688911B2 - Moving correction method for underground pipes - Google Patents

Description

TECHNICAL FIELD The present invention relates to a construction method for levitating a pipe buried in the ground without digging up the soil when the pipe is in a slackened state, and corrects the movement of the pipe. It is a thing.

"Prior art" Conventionally, to correct the slack of the underground buried pipe due to uneven settlement of the ground, etc., by digging up the soil and modifying it, or as a method of modifying without digging up the soil, A so-called grout method is known in which a solidified body made of a mixture of cement and water glass is injected into the lower side of the pipe to solidify it, thereby pushing up the slack portion of the pipe.

Further, a method has been proposed in which a high-pressure water jet is jetted to one ground of the slack portion of the pipe to make it muddy, the mud is sucked out, and this is pressure-injected to the symmetrical ground side to move and correct the pipe.

[Problems to be Solved by the Invention] In the above-mentioned grout method, there is a fundamental difficulty that it is difficult to set an optimum amount of the injection material for the movement correction of the pipe.

Further, the proposed method by suction and pressure injection of mud requires a suction device and a pressure injection device for mud, which increases the scale of the device, and even if mud is pressed into the symmetrical ground side, Flows around the and goes to the suction side,
The movement of the pipe may not be corrected properly.

The present inventor has variously studied other methods for replacing the above-mentioned clout method with respect to the movement correction method of the buried pipe, and as a result, when burying the pipe in the ground, the earth and sand are backfilled in the periphery of the pipe. Since a sediment layer is generally formed around the buried pipe, it was found that the buried pipe can be moved and corrected by utilizing the fluidization phenomenon of the sediment layer.

As a result of the research on fluidization phenomenon of the saturated sand layer triggered by the investigation of the cause of the so-called Niigata earthquake,
The cause of fluidization of sediment is explained as follows.

Generally, loosely accumulated sand becomes dense when subjected to vibration, and conversely sand that is dense becomes loose when subjected to vibration, but the void ratio (limit void ratio) in the limit state of this density
When less dense sand is saturated with water and subjected to vibration, the pore water pressure rises to reduce the gap and the contact pressure (effective stress) between particles decreases, resulting in shear resistance. When the shear resistance is reduced and the shear resistance is almost eliminated, the sand becomes like a fluid (fluidization of the sand), the heavy object on the surface side of the sand gradually sinks, and the lightweight object buried in the sand. Is said to exhibit the phenomenon of rising.

Since the underground pipe is a hollow body, it is a lightweight material in the earth and sand. Therefore, it is possible to float the pipe by causing a fluidization phenomenon in the earth and sand layer formed around the underground pipe. It is possible.

An object of the present invention is to solve the drawbacks of the conventional pipe movement correction construction method, and by utilizing the above-mentioned sand fluidization phenomenon, it is possible to surely correct the floating movement of the underground pipe. To provide.

"Means for Solving the Problem" The method for moving and correcting a underground buried pipe according to the present invention is to construct a casing pipe from the ground on the side of the pipe buried underground,
The earth and sand around the pipe are supplied with water through the casing pipe or a separately built water supply pipe so that the earth and sand are saturated with water, and the rod-shaped oscillating device is attached to the rear end of the rod-shaped oscillating device through the casing pipe. The fluidization phenomenon is generated by inserting the cord of the above while inserting it and applying vibration to the above-mentioned earth and sand, and a heavy and light object in the earth and sand sinks and a light object floats. This is a method to correct the slack of the pipe body.

"Operation" The earth and sand are usually backfilled around the pipe buried in the ground, but a casing pipe is installed from the ground on the side of the buried pipe to be moved and corrected, preferably on both sides,
A large amount of water is supplied to the earth and sand around the pipe through this casing pipe or through a water supply pipe built separately. As a result, the earth and sand are saturated with water, and the fluidization phenomenon easily occurs.

In this state, a rod-shaped oscillating device such as a high-frequency inner vibrator with a built-in motor is inserted through the casing pipe while the cord at the rear end is being retracted, and the oscillating device vibrates the earth and sand. When the casing pipes are installed on both sides of the pipe, the oscillating device is inserted from both casing pipes to apply vibration from both sides. Since the geological conditions of the part where the pipe is buried vary depending on the location, in the case of a geological formation with good drainage, vibration is applied while supplying water.

In this way, when vibration is applied to the earth and sand saturated with water by the oscillating device, the earth and sand are fluidized, and the embedded pipe, which is a hollow body, is a lightweight material in the earth and sand and gradually floats up. The slack in the tube is corrected.

"Example" An example of the present invention will be described with reference to the drawings. In the figure, 1
Is an underground pipe such as a water pipe, but the sagging phenomenon shown in Fig. 1 may occur due to uneven subsidence,
It is necessary to levitation-correct this to a predetermined level L position.

Since the earth and sand are backfilled around the underground buried pipe 1 at the time of burial to form a sediment layer 2, the ground GL is casing on both sides of the buried pipe 1 at predetermined intervals along the buried pipe 1. Build pipes 3 and 4 until reaching the sediment layer 2. In addition to the casing pipes 3 and 4, a water supply pipe 5 as shown by an imaginary line may be built.

Through the casing pipes 3 and 4 or the water supply pipe 5
A large amount of water W is supplied to the earth and sand layer 2 via the to make the earth and sand layer 2 saturated with water. Sediment layer 2 in this state
Is in a state where the fluidization phenomenon is likely to occur, and in this state, the rod-shaped oscillating device 6 is inserted through the casing pipes 3 and 4, and the earth and sand layer 2 is vibrated.

As the rod-shaped oscillating device 6, a high-frequency inner vibrator with a built-in motor, which has been conventionally used for concrete pouring work, can be used, and the cord 7 is lowered from the casing pipes 3 and 4 to the earth and sand layer 2. As described above, vibration is continuously applied to the earth and sand layer 2 which is saturated with water. In addition, when the drainage is in good formation conditions, vibration is applied while continuing water supply.

The volume occupied by the pipe 1 in the earth and sand is large, but since the pipe is a hollow body, it is a lightweight material in the earth and sand.
Due to the action in the fluidization phenomenon of earth and sand, that is, the action of a heavy object sinking and the lifting of a light object, a heavy object 8 such as a stone in the earth and sand sinks and the pipe 1 which is a lightweight object gradually floats up. Can be modified. The level of the levitation-corrected pipe 1 can be easily detected, so that the vibration by the oscillating device 6 is stopped while the pipe is corrected to a predetermined position.

[Advantage of the Invention] According to the method for correcting the movement of the underground pipe according to the present invention, the casing pipe is built from the ground on the side of the buried pipe to be moved and corrected, and this casing pipe or the water supply pipe built separately is installed. A large amount of water is supplied to the earth and sand backfilled around the pipe to make the earth and sand saturated with water, and in this state, the rod-shaped vibrating device is inserted through the casing pipe. By vibrating the earth and sand with the oscillating device, a fluidization phenomenon can be generated in the earth and sand, and the pipe, which is a lightweight object, can be lifted and corrected.

Therefore, of course, there is no need to carry out a large excavation work to move and correct the pipe, and it is not necessary to inject a large amount of solidification material as in the conventional grout method, and no large-scale device is required to correct the pipe movement. The construction can be done easily and quickly.

[Brief description of the drawings]

The drawings show an embodiment of a method for moving and burying underground pipes according to the present invention. Fig. 1 is a sectional view showing the condition of the underground pipes to be lifted and corrected, and Fig. 2 is a sectional view showing the working condition. is there. 1: Underground pipe, 2: Sediment layer, 3, 4: Casing pipe, 5: Water supply pipe 6: Rod-like vibration device, 7: Cord

Claims (1)

(57) [Claims] 1. A casing pipe is installed on the side of a pipe buried in the ground from the ground, and water is supplied to the earth and sand around the pipe through the casing pipe or a water pipe separately installed to supply the earth and sand with water. In a saturated state, the rod-shaped oscillating device is inserted through the casing pipe while the cord at the rear end of the rod-shaped oscillating device is inserted, and a fluidization phenomenon is generated by applying vibration to the earth and sand, A method for correcting the movement of underground pipes, characterized in that a hollow and lightweight pipe is levitated by using the action of a heavy object sinking and a light object levitating, and the slack of the pipe body is levitated and corrected.