JP2008038543A - Construction method and device for draining groundwater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of a conventional device for draining ground water wherein a high water pressure is applied to a drainage well 9 since the water level in the drainage well 9 (liner plate) is suddenly raised by sliding clods in a landsliding zone, local severe rain due to abnormal weather from the inner wall surface of the drainage well 9 formed in a soft ground layer 6 such as a soil-improved zone and a soil pressure retaining wall 2 facing rivers or coasts, and a strong water draining force by a multiple tube 1 for civil engineering, the high-pressure water flows back to the multiple tube 1 at a position lower than the water level, the water flows from the inside of the multiple tube 1 into the ground to raise a water pressure between the gaps, and the possibility that landslide or collapse of earth occurs is produced. <P>SOLUTION: The lower end 1' of the multiple tube 1 for civil engineering buried in the ground projects to the outside of the soil pressure retaining wall 2, and an opening end surface 3 is closed by a flap gate 4 loosely supported on the upper end of the opening end surface 3 of the lower end 1' to stop the reverse flow to the multiple tube 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for removing groundwater by a civil engineering multiple pipe and preventing a reverse flow to the multiple pipe to prevent a landslide or a collapse of a natural ground.

  Conventionally, civil engineering multiple pipes have been used for underground drainage in landslide zones, ground improvement zones, and the like (for example, Patent Document 1).

  Groundwater was discharged from the cliff face such as the landslide zone using the civil engineering multiple pipe, and landslide was prevented by using the anchor as well (for example, Patent Document 2).

  The above-mentioned multiple pipes are inserted directly into the ground of the borehole, and the borehole wall tends to collapse, so a porous casing can be inserted into the borehole to prevent the borehole from collapsing. Was significantly improved (for example, Patent Document 3).

  By the way, in order to further improve the water collection capacity of the multiple pipes inserted into the porous casing, a water collection well (collection well) is excavated from the surface and the inner peripheral surface is surrounded by a liner plate to form an earth pressure support wall. A plurality of boreholes were drilled upward from the water well, and the above-mentioned multiple pipes were inserted to collect groundwater in the water collection well.

However, groundwater flows into the drainage well from the multiple pipes and is stored and the water level rises. However, the drainage capacity of stored water due to drain boring or pumping up is insufficient, the water level of the drainage well rises, the upward gradient of the stored water rises in the multiple pipes, and the groundwater enters the ground from the multiple pipes. The backflow was full.
JP 61-179912 A JP-A-6-88335 Japanese Patent No. 2777346

  The present invention relates to localized torrential rain due to abnormal weather from the inner wall of a drainage well drilled in a soft ground layer such as the above-mentioned landslide zone, ground improvement zone, etc. Due to the strong water collection capacity of the pipe, the water level in the water collection well (liner plate) suddenly rises, and this causes high water pressure on the water collection well and backflow to the civil engineering multiple pipes located below the water level. As a result, water flowed into the ground from the multi-pipe for civil engineering, and the pore water pressure increased, causing landslides and collapse of the ground.

  The present invention aims to solve this problem.

In order to achieve the above object, the present invention firstly includes a flap gate that protrudes outside the earth pressure support wall at the lower end portion of the underground pipe for civil engineering and is loosely supported on the upper end portion of the opening end surface of the lower end portion. Groundwater drainage construction method characterized by closing the open end face and preventing backflow to the multiple pipes,
Second, the groundwater drainage construction method according to the first invention, wherein the earth pressure support wall is formed on the ground surface,
Thirdly, the earth pressure support wall according to the first invention, wherein the earth pressure support wall is formed by a liner plate of a drainage well,
Fourth, the groundwater draining method according to the first invention, wherein the earth pressure support wall is a retaining wall of a river or a coast,
Fifth, the lower end portion of the underground buried water collecting multi-pipe protrudes outside the earth pressure support wall, the open end surface of the lower end portion is inclined upward toward the support wall, and the free end portion of the open end surface A groundwater drainage device characterized in that the open end face is closed with a supported flap gate to prevent backflow to the multiple pipe;
Sixth, the groundwater drainage device according to the fifth invention, wherein the earth pressure support wall is formed by a liner plate of a catchment well,
Seventhly, the earth pressure support wall according to the fifth invention, wherein the earth pressure support wall is a retaining wall of a river or a coast,
Consists of.

  Therefore, a drainage well is drilled below the groundwater level from the concrete surface or the ground surface of a soft ground layer such as a landslide zone or a ground improvement zone, and an annular steel liner plate is laminated on the inner wall to form an earth pressure support wall.

  Moreover, the earth pressure support wall by the concrete retaining wall of the soft ground layer which touches the river or the coast is formed.

  In the present invention, a plurality of bores are provided in an upward gradient with an interval from the outside of the earth pressure support wall into the ground, and a multi-pipe for civil engineering is inserted into the borehole to support the hole wall and the ground. A multi-pipe group for underground civil engineering is formed.

  In this invention, the lower end part of the said water collection multiple | multiply pipe | tube is made to protrude outside the said earth pressure support wall, and the opening end surface of this lower end part is opened outside.

  The opening end face is closed with a flap gate loosely supported on the upper end thereof to form a check valve for the opening end face.

  Since the present invention is configured as described above, there is no risk that water discharged outside the earth pressure support wall from the plurality of civil engineering multiple pipes embedded in the soft ground layer will flow backward at the lower end opening of the multiple pipes. There is an effect that can suppress the rise of the groundwater level of the soft ground layer during local heavy rain.

  A landslide mass 7 is present on the bedrock 5 through a stationary mass 10, and a drainage well 9 is drilled vertically from the surface 8 to collect groundwater 10 and drain from a drain pipe 11.

  The drainage well 9 is circular, and the earth wall supporting wall 2 of the formation 7 is formed by stretching a steel annular liner plate 2 'on the inner wall surface.

  In place of the drainage well 9, the concrete retaining wall 2 ″ is the earth pressure support wall 2 in the terrain in contact with the river or the coast as shown in FIGS.

  A plurality of boring holes 12 are drilled upwardly from the earth pressure support wall 2 into the ground, and a plurality of porous outer tubes 13 and 13 are connected and inserted into the boring holes 12 by connecting pipes 16; Further, the non-porous inner tube 17 is inserted into the porous outer tube 13 to form the multiple tube 1.

  As shown in FIGS. 3 and 4, the multi-tube 1 has a plurality of non-porous inner pipes 17 and 17 fitted into the connecting pipe 16 in the porous outer pipes 13 and 13, respectively, and a lower end part in the lower stage. The outer heavy pipe 1 is formed with a water passage gap t interposed between the outer circumference of the non-porous inner pipe 17 and the inner circumference of the porous outer pipe 13.

  A packer (water-expandable rubber) 14 is fitted to the middle outer periphery of the connecting pipe 16, and after inserting the porous outer pipes 15, 15 into the boring hole 12, the packer 14 absorbs water and has an outer diameter. Is expanded and crimped to the inner peripheral surface of the boring hole 12, the boring hole 12 and the porous outer pipe 15 are sealed, and a water stop ring is formed between the connecting pipe 16 and the boring hole 12.

  Between the boring hole 12 and the porous outer tube 15 and the connecting tube 16, water is stopped by a packer 14, and a gap t is interposed between the porous outer tube 15 and the nonporous tube 17. 16 is formed.

  The civil engineering multiplex pipe 1 is inserted into a plurality of boreholes 12 drilled in an upward gradient from the earth pressure support wall 2 by the annular liner plate 2 ′ or the retaining wall 2 ″ of the catchment well 9 toward the ground. Inserted, and projecting the lower end 1 ′ to the outside of the liner plate 2 ′, the ground surface 8 or the retaining wall 2 ″,

  A steel flap gate 4 is provided on a horizontal shaft 3 ′ which is slanted upward at the upper end of the opening end surface 3 by inclining the opening end surface 3 of the projecting lower end 1 ′ toward the earth pressure support wall 2. The flap gate 4 can form a check valve for the elliptical opening end face 3, and supports earth pressure by raising and lowering the water level outside the earth pressure supporting wall 2, that is, inside the water collecting well 9, outside the surface 8 or retaining wall 2 ". The water in the multiple pipe 1 is discharged outside the wall 2.

  However, as the groundwater level 10 'rises due to torrential rain or the like, the water level and water pressure outside the collecting well 9 and the surface 8 or the retaining wall 2 "flowing from the multiple pipe 1 rises, so that the flap gate 4 has the opening end face 3 By closing and preventing backflow, there is no possibility that the rainwater flowing back through the multiple pipes 1 will flow back into the sliding soil block.

  In FIG. 3 and FIG. 4, s is a water collecting slit of the porous outer tube 15.

  In the present invention, the groundwater 10 caused by heavy rain and the like flowing out of the earth pressure support wall 2 is stopped by the flap gate 4, and landslides and ground collapse due to the groundwater rising to the ground or the ground due to the backflow are prevented.

It is a longitudinal cross-sectional view of underground underground water collection multiple pipe, a water collection well, and a drain hole. It is a cross-sectional plan view by the FIG. 1A-A line. It is a longitudinal cross-sectional view of underground underground water collection multiple pipe and a flap gate. FIG. 4 is a partially enlarged view of FIG. 3. (A) The figure is a longitudinal sectional view of the retaining wall in the river or the coast, and (b) the figure is a longitudinal sectional view of the flap gate open state.

Explanation of symbols

1 underground pipe for civil engineering 1 'lower end 2 earth pressure support wall 3 open end face 4 flap gate

Claims (7)

The lower end of the underground pipe for civil engineering is projected outside the earth pressure support wall,
Closing the open end face with a flap gate loosely supported on the upper end of the open end face of the lower end;
A groundwater draining method characterized by preventing back flow into the multiple pipe.   The groundwater draining method according to claim 1, wherein the earth pressure support wall is formed on the ground surface.   The groundwater draining method according to claim 1, wherein the earth pressure support wall is formed by a liner plate of a catchment well.   The groundwater draining method according to claim 1, wherein the earth pressure support wall is a retaining wall of a river or a coast. The lower end of the underground pipe for civil engineering is projected outside the earth pressure support wall,
An opening end surface of the lower end portion is inclined upward toward the support wall;
Closing the opening end face with a flap gate loosely supported on the upper end of the opening end face;
A groundwater draining device characterized in that it prevents back flow into the multiple pipe.   6. The groundwater draining device according to claim 5, wherein the earth pressure support wall is formed by a liner plate of a catchment well.   The groundwater draining device according to claim 5, wherein the earth pressure support wall is a retaining wall of a river or a coast.

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