JPH06322772A - Drainage method in landslide area or the like - Google Patents

Abstract

PURPOSE:To dry up a site by installing a ring which includes a water expandable high polymer powder material at a proper spacing in the longitudinal direction of a water collection pipe having elasticity and plasticity and installing a net cylinder having elasticity and plasticity outside the ring and continuously installing a drain pipe in the vertical direction from an air vent valve installed on the downstream side of the water collection pipe and creating a negative pressure prevailing throughout the water collection pipe. CONSTITUTION:A water expandable and high polymer material-made ring 2 is installed in the longitudinal direction of a water collection pipe 1 having elasticity and plasticity provided at a proper spacing. Then, a cylinder-shape net 3, which is made of an elastic and plastic material, is wound around the outside of the water collection pipe 1. Then, an air vent valve 4 is installed in the outlet of the water collection pipe 1, to which a drain pipe 5 is connected where the drain pipe 5 is tied up with an U-shaped pipe opposite to an U-shaped pipe having a head in a specified length in the vertical direction. The gaseous body in the water collection pipe is extracted with a drain pump from the air vent valve 4 in the upper part of the drain pipe 5, thereby making a condition that a negative pressure prevails in the water collection pipe 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage method for landslides.

[0002]

2. Description of the Related Art Conventionally, in a landslide area, etc., a cylindrical water collecting well having a diameter of several meters and a depth of several meters to several tens of meters is provided at a downstream portion of a region where partial drainage is required. In the diagonally upward direction upstream from the well wall, several water collecting pipes having water collecting holes in a pipe having a length of several meters to a dozen meters are provided in a fan-like shape in plan view, The method of draining the water in the stratum was used. However, the water collection efficiency is often low. On the other hand, in the landslide area, there was a large difference between the direction of the slip and the moving speed, and the water collection pipe was broken or crushed.

[0003]

The cause of landslides is an increase in the slope of a mountain due to structural movement. However, the resulting opening cracks and rapid weathering of landslide blocks increase precipitation and surface water intrusion. It is a major factor that the water raises the water table to increase the buoyancy in the stratum, and the increase in water content lowers the angle of repose of the stratum.

Further, since the landslide area has soil conditions that make it a rich cultivated area in the mountainous area, it is easy to cause artificial conditions such as cutting down trees and clearing them, and irrigating the fields there. The increase in water volume is also a major factor.

An object of the present invention is to provide an epoch-making drainage method which eliminates the above-mentioned drawbacks.

For that purpose, the water content in the stratum and the groundwater table are made lower, and as one of the means, a negative pressure drainage state in which the water collecting function becomes high in the water collecting pipe of the water collecting conduit or the underdrain of the upland field. It uses a water collecting pipe that keeps.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a water collecting pipe made of a material having elasticity and plasticity, which is provided with rings containing a water-expandable polymer powder material at appropriate intervals in the length direction thereof. A mesh cylinder made of a material having elasticity and plasticity is provided on the outside, an exhaust valve is provided at the downstream end of the water collection pipe, and a drain pipe is continuously provided from here to make the inside of the water collection pipe a negative pressure condition. This is a drainage method for draining landslide areas.

[0008]

[Embodiment] As a necessary device, a water collecting pipe 1 made of a material having elasticity and plasticity is used, and a ring 2 ... A cylindrical mesh body 3 made of a material having elasticity and plasticity is wound around the.

An exhaust valve 4 is provided at the outlet of the water collecting pipe 1, and a drain pipe 5 having a U-shaped pipe having a vertical head of 1 m or more and a reverse U-shaped pipe is connected to the exhaust valve 4.

The side surface of the ring portion is made of rubber or its bellows structure so that a volume increase of several hundred times due to water absorption of the water-expandable polymer material expands only in the outer direction of the ring 2. .

When the water collecting pipe 1 is installed, in order to prevent expansion of the filling material of the rings 2 ... due to absorption of water, a steel pipe covered with a water-impermeable sponge that softly wraps the water collecting pipe, and an inner wall of the water collecting pipe. Both the inner pipe made of a material having elasticity and plasticity to prevent water from entering from the inside are attached to the water collection pipe and inserted into the chisel hole, and after installation, the steel pipe and the inner pipe are pulled out at the same speed.

Bending and cutting of the water collection pipe due to a partial difference between the direction of the landslide and the moving speed are dealt with by the deformation of the material of the water collection pipe, and the cylindrical shape stretched on the outside of the ring expanded by water. The net holds the space for collecting water.

The generation of negative pressure in the water collecting pipe is preferably as large as possible in view of the drainage effect, but in this device, the negative pressure of about 1 m of water column is the maximum.

The method of generating or increasing the negative pressure is to draw a large amount of gas in the water collecting pipe 1 in a short time from the exhaust valve 4 above the drain pipe 5 with an exhaust pump, and to drain the gas to the downstream end with a length of 1 m or more. There is a method in which water is stretched vertically in a pipe having a valve 6, its upstream end is connected to the exhaust valve 4, and a drain valve at the downstream end is opened to exhaust gas corresponding to the amount of drainage.

A major factor that hinders the generation of negative pressure is the presence of a large space that forms a gap between the water collection pipe 1 and the surrounding formation, and a ring is provided to prevent the atmosphere from flowing into the water collection pipe through this space. 2 ... was set up. The volume of the ring is several hundred times as large as the expansion rate of the water molecule polymer powder material, and the space is closed by the powder material turning into agar.

The subsequent negative pressure holding state of the atmospheric pressure in the water collecting pipe 1 is indicated by the water column height h which is the water level difference between the long vertical portion of the drain pipe 5 and the outlet portion. When the air pressure inside this water collection pipe is set to −0.1 at which the height of the water column is 1 m, the water of pF2 or less is generated by the capillary poten- tial, which is the main component of the circulating aqueous groundwater around the water collection pipe and above the water collection pipe. Since the water table is not formed in this area because it is drawn out, and the water in the large pore size part of the pore size in the formation is drawn out, so a water channel develops in the formation around the catchment pipe. However, the water collection capacity from the stratum will increase over time.

When used for underdrain in fields, etc., the depth of 0.5 m to 1 m at which the voids in the surface layer do not communicate with the atmosphere
Negative pressure is unlikely to occur unless installed below.

This method can be carried out when the water content of the formation is partially lowered or the water table is lowered to cause desiccation of the land, and the vertical height of the U-tube and the exhaust gas can be reduced. By increasing the displacement of the valve, water in smaller gaps in the formation can also be withdrawn.

[0019]

INDUSTRIAL APPLICABILITY The method of the present invention can be carried out when the water content of the formation is partially lowered or the water table is lowered to cause desiccation of the land. By increasing the vertical height and the amount of exhaust from the exhaust valve, water in smaller gaps in the formation can also be withdrawn.

[Brief description of drawings]

FIG. 1 is a structural diagram for implementing the present invention.

[Explanation of symbols]

 1 Water collecting pipe 2 Ring 3 Cylindrical mesh body (mesh cylinder) 5 Drain pipe

Claims (2)

[Claims] 1. A water collecting pipe made of a material having elasticity and plasticity, in which a ring containing a water-expandable polymer powder material is provided at appropriate intervals in the lengthwise direction, and a ring having elasticity and plasticity is provided outside thereof. A drainage method in a landslide area in which a mesh tube made of a material is provided, an exhaust valve is provided at the downstream end of the water collection pipe, and a drainage pipe is continuously provided from there in a vertical direction to drain the water under the negative pressure condition in the water collection pipe. . 2. A method in which a steel pipe having a water-impermeable sponge inside is covered on the outside of the water collecting pipe, and an inner pipe made of a soft material that adheres to the inside of the water collecting pipe is wrapped around the steel pipe, and both pipes are pulled out at the same time. Drainage method in landslide areas, etc. described in 1.