JPH05230823A - Horizontal drain material laying method for improving extremely poor subsoil - Google Patents

Abstract

PURPOSE:To lay horizontal drain materials in extremely poor subsoil treated place of a small area at low cost. CONSTITUTION:A large number of drain materials 3 are arranged in parallel with each other according to the laying intervals, and the respective drain materials 3 are connected to each other with every constant length by means of string like materials 4 crossing these drain materials 3, and are formed in a net like body 5, and this is wound round a core material 7, and is formed as a roll body 9. Every time poor soil is inputted in a prescribed thickness, this roll body 9 is carried in/spread on this poor subsoil 2, so that the horizontal drain materials 3 can be laid in a multistage shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a horizontal drain consolidation method for a dredged soil in which cohesive soil on the seabed is dredged by a pump-type dredger, and an ultra-soft soil in which slurry-like waste discharged from a chemical factory is stored. The present invention relates to a horizontal drain material laying method for improving ultra-soft ground for improvement.

[0002]

2. Description of the Related Art Conventionally, there is a horizontal drain consolidation method as a method for improving a slurry-like ultra-soft ground in a short period of time. This construction method is a construction method in which a cylindrical drain material made of plastic board is horizontally embedded in soft ground, and a negative pressure is applied to the ground from one end of the drain material to forcibly drain the ground.

In the conventional method of burying a horizontal drain material in this construction method, a pier for exclusive use for burying is assembled at a disposal site, a mandrel is penetrated from the pier to a predetermined depth position in the ground, and the pier is towed in that state. In general, the drain material is laid by unwinding it from the mandrel according to the movement.

[0004]

Such a conventional horizontal drain material laying method is not so problematic when the side of the disposal site of the dredged soil or the waste to be improved is 100 m wide. However, when the disposal site is small, the ratio of the cost of manufacturing the drainage material embedded barge to the total construction cost is large, and the ground improvement cost per unit volume is high.

In view of the above conventional problems, the present invention does not provide a method for laying a horizontal drain material for improving ultra-soft ground, which is capable of economically and efficiently burying a horizontal drain material even in a narrow disposal site. It is a thing.

[0006]

The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows.
Laying of ultra-soft ground improvement horizontal drain material by inserting soft soil such as cohesive dredged soil into the disposal site and burying a large number of ground improvement drain materials horizontally in the ground consisting of the injected ultra-soft soil In the method, a large number of the drain members are arranged in parallel at a desired laying interval in advance, and the drain members are connected by a number of string-shaped members in a direction intersecting with the drain member to form a net-like body. Rolled in a roll to form a roll, the roll is loaded and spread on the surface of the ultra-soft ground every time the ultra-soft soil introduced into the disposal site reaches a certain thickness. It is to put soft soil on it.

[0007]

In the horizontal drain material laying method of the present invention, when the ultra-soft soil is thrown into the disposal site and the ultra-soft ground in the disposal site has a certain thickness, the roll is wound along the edge of the disposal site. After stretching, spread on the ground surface. In this case, the edge portion of the mesh material on the end side of the drain material is fixed with a fixing tool such as a pile, and the wound body can be laid on one surface by rolling in a spreading direction. Then, after unfolding, the both ends of the string-like material are fixed by a fixture such as a pile, so that the movement can be prevented. In this way, the horizontal drain material having a multi-stage arrangement in the thickness direction of the ground is buried by expanding the net-like body each time the ultra-soft soil is thrown into a certain thickness.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the embodiment of the present invention will be described with reference to the drawings. 1 and 2 show an ultra-soft ground in which a horizontal drain material is buried. In the figures, 1 is a bank surrounding the treated land, and 2 is ultra-soft ground formed by pouring slurry into the treated land. 3 is a horizontal drain material. The horizontal drain members 3, 3, ... Are embedded in the ground 2 in a multi-tiered arrangement at constant depths, and a large number of them are horizontally embedded at substantially the same height.

The horizontal drain members 3, 3, ... Are cut into laying lengths in advance and are laid at the same height position as shown in FIG. 1 prior to laying. A net-like structure in which a large number of cord-shaped members 4 and 4 made of ropes are arranged in parallel with each other at the same intervals and are arranged in a direction orthogonal to the drain members 3 and 3 ... A body 5 is formed, and further, an end closing cap 6a is fitted to one end of each drain member 3, 3 ... And the end on the cap side is fixed to a winding core member 7 made of a steel pipe. After that, the mesh body 5 is sequentially wound around the core material 7 to form a wound body 8.

In this way, the drain materials 3, 3 ... Are preliminarily set as the winding body 8 and buried in the ground. The embedding is performed by constructing the treated land by the embankment, and then forming a slurry-like superconductor therein. Soft soil is added until the height of the first horizontal drain material is buried.

Then, the winding body 8 is drawn into the ground surface,
Along the edge of one of the treated grounds. After that, the winding body 8 is rolled toward the other processing ground edge portion which is opposed, and the mesh body 5 is sequentially developed and spread on the ground. In this way, the net-like body 5 is spread over one surface to the side of the other treated ground, and then the drain hose 9 is connected to the open side edge of the drain members 3, 3, ... Via the connection cap 6b, and the tip thereof. To extend above the bank 1. Further, the core material 7 is connected to the plurality of piles 11 via the connection ropes 10 and both ends of each cord-like material 4, 4 forming the mesh body 5 are piles 12, 12 on the bank 1. ......
Fixed to.

After the completion of the laying of the first stage drain material in this manner, the introduction of the super soft soil is started again. Then, after the top surface of the ground reaches the drain material laying height of the second step, the charging is stopped, another winding body 8 is drawn in and expanded in the same manner as described above, and the mesh body 5 is laid on the ground surface. Then, lay and fix the second-stage horizontal drain members 3, 3 ... In this way, throwing in ultra-soft soil, pulling in the roll, spreading,
The horizontal drain members 3, 3 ... are laid in the required several steps by repeating the fixing of the mesh body, and the horizontal drain members are not embedded as shown in FIG. cover.

Incidentally, the consolidation of the ground by the horizontal drain material buried in this way is performed by connecting the drainage hoses 9, 9 ... To the water collecting pipe 13 and reducing the pressure inside the water collecting pipe 13 by the decompression pump 14. By doing each drain material 3,3 ……
Negative pressure is applied to the ground through to force the water to drain.

[0014]

As described above, in the horizontal drain material burying method of the present invention, the drain materials are connected by a string-like material in advance to form a mesh body so as to have a necessary laying interval, and this is wound up. Since the roll is carried on to ultra-soft ground and laid by unfolding it, construction can be done without the use of a conventional dedicated drain burying vessel, and therefore the cost does not increase even on a small area of treated land. .

Further, since the laying work is performed by unfolding the winding body, it can be done in a short time and the work efficiency at the site is high.

Further, since the net is preliminarily formed, the laying intervals are necessarily constant, and the improved ground can be easily homogenized. Furthermore, if both ends of the string-like material are fixed with piles or the like, the drain interval can be kept constant without moving even when the next soft soil is input, and uniform improvement can be achieved.

[Brief description of drawings]

FIG. 1 is a plan view of a horizontal drain material laid state according to the present invention.

FIG. 2 is a sectional view of a drain material laid according to the present invention in an embedded state.

FIG. 3 is a perspective view showing a developed state of a roll body wound with a mesh body used in the present invention.

[Explanation of symbols]

 1 dam body 2 super soft ground 3 horizontal drain material 4 string material 5 mesh body 6a end closing cap 6b connecting cap 7 core material 8 winding body 9 drainage hose 10 tie rope 11, 12 pile 13 water collecting pipe 14 decompression pump 15 Sealing sheet

Claims (1)

[Claims] 1. An ultra-soft ground improvement in which soft soil such as cohesive dredged soil is put into a disposal site, and a large number of ground improvement drain materials are embedded horizontally in the soil made of the injected ultra-soft soil. In the horizontal drain material laying method for use, a large number of the drain materials are arranged in parallel at a desired laying interval in advance, and the drain materials are connected by a number of string-like materials in a direction intersecting with the drain material to form a net shape. The body is rolled into a roll, and the roll is loaded onto the surface of the ultra-soft ground whenever the ultra-soft soil introduced into the disposal site reaches a certain thickness. The method for laying a horizontal drain material for improving ultra-soft ground is characterized in that the soil is spread, and then soft soil is poured on the soil.