JPH03166414A - Ground improving method and device thereof - Google Patents

Abstract

PURPOSE:To pull out only casing securely by throwing sand into a casing passing through the ground to form a sand pillar, and thereafter, mixing the slipping agent with the air to be pressed into the casing at the time of pulling out the casing. CONSTITUTION:A device is formed with a casing 1 having a cover 3 to be opened and closed with a cylinder 2, an air supply source 4 and a switching valve 6. A slipping agent supply part 7, a branch 9, a slipping agent constant quantity pushing device 10 and valve check valves 11, 12 are provided in the upstream of the switching valve 6. The sand is thrown into the casing 1 to be sealed with the cover 3, and a sand pillar is pressurized with the pressurizing air to form the trend material B. Next, at the time of pulling the casing 1, when the air in which the slipping agent is mixed is supplied into the casing 1, the slipping agent adheres to the interface of the casing 1 and the trend material B to reduce the friction. Only the casing 1 can be thereby pulled out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for improving soft ground and a soil improving device used to implement this method.

[Conventional technology]

The sand drain method and pack drain method are well known as construction methods for improving soft ground.

The former sand drainage method involves inserting a caning into the ground, pouring sand as a drainage material into the caning, sealing the upper end of the casing, and supplying air to the upper part of the casing to pressurize the upper part of the drain hole. The sand pillar is constructed by pulling out the gating from the ground and leaving drainage material in the ground.

In addition, in the latter back drain method, a casing is inserted into the ground, a water-permeable cylindrical bag is pushed into the casing, and sand, which becomes the drain material, is thrown into the cylindrical bag to form a sand column. The upper part of the post-gacing is sealed, air is supplied inside, and the casing is pulled out while pressurizing the sand column from above, leaving a sand bar on the ground.

The sand drain method and punk drain method described above are
When the casing is being pulled out, the sand column is pressurized from above using pressurized air to prevent the sand column from moving along with the casing being pulled out. [Problems to be Solved by the Invention] However, the weight of the sand and sand columns put into the casing presses against the inner circumferential surface of the casing due to the weight from above, resulting in a blockage state. Even when pressure is applied, the frictional force at the interface between the inner circumferential surface of the casing and the sand column is extremely poor, and the casing and sand column move together during handling, resulting in the inability to form a normal sand column. There is a problem.

Therefore, the object of this invention is to provide a ground improvement method that improves the peelability between the inner circumferential surface of the casing and the sand pillar during the casing pulling process, and that allows only the casing to be reliably pulled out to form a normal sand pillar. An object of the present invention is to provide a ground improvement device that can be implemented with a simple structure.

[Means to solve the problem]

In order to solve the above-mentioned problems, the first invention introduces drain material into a guising inserted into the ground, pressurizes air into the upper part of the casing whose upper end is sealed, and pressurizes the drain material. This is a ground improvement method in which the casing is pulled out and drain material is left on the ground, and a slip agent is mixed with the air that is press-fitted into the casing. Similarly, in the second invention, the upper end can be opened and closed and sealed, and the drain material is introduced into the casing while inserted into the ground.The air flows into the casing in the middle of the air supply path connecting the upper part of the casing and the air supply source. This system employs a structure that includes a lubricant supply section that mixes the lubricant with the air. [Operation] After pouring drain material into the casing inserted into the ground,
If the upper end of the casing is sealed and air mixed with a slip agent is supplied to the upper part of the casing during the casing drawing process, the drain material is pressurized from above and at the same time the slip agent adheres to the interface between the casing and the drain material, causing the casing to Since the frictional force of the drain material is reduced, the casing and drain material do not rise together, and the casing can be easily pulled out with the drain material remaining on the ground. [Embodiments] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

As shown in the figure, a cylindrical casing 1 has an opening/closing M3 operated by a cylinder 2 or the like attached to its upper end, and a drain material B is poured into the casing 1 while the casing 1 is inserted into the ground A. Although not shown in the drawings, the casing 1 is inserted into the ground IA by means such as pressing, driving, excavating, and perforating using a working machine.

The upper part of the casing 1 and an air supply #4 such as a compressor are connected through an air supply path 5, and in the middle of this supply path 5, there is a switching valve 6 for opening and closing the passage.
A liquid lubricant supply section 7 is provided at a position upstream of the pump. The lubricant supply section 7 connects the air supply path 5 and the lubricant tank 8 through a branch path 9, and connects a lubricant quantitative extrusion device 10 to the branch path 9 on the upstream side sandwiching the extrusion device 10. and check valves 1) and 12 are provided at downstream positions,
Both check valves 1) and 12 are connected to the air supply path 5 from the lubricant tank 8.
It is installed to allow the slip agent to flow to the side, but to prevent it from flowing in the opposite direction.

The material of the slip agent to be used is not particularly limited as long as it has the ability to reduce the frictional force at the interface between the casing 1 and the drain material B and is non-polluting. An example is an aqueous solution, and the supply amount may be selected depending on the quality of the sand.

Next, the ground improvement method will be explained.

With the casing 1 inserted into the ground A to a predetermined depth, the drain material B is poured into the casing 1.

In the case of the sand drain method, the drain material B is sand and is directly thrown into the casing 1.

Furthermore, in the case of the back drain method, a long cylindrical bag is dropped into the casing, and sand is thrown into the cylindrical bag to form the drain material B.

When the drain material B is completely poured into the casing 1, the opening/closing lid 3 is closed to seal the upper end of the casing 1, and the air supply path 5 is connected to the upper part of the casing 1.The casing 1 is clamped using work NIT and pulled out. At this time, the switching valve 6 of the air supply path 5 is operated to open the air supply path 5, and the casing 1 is
Supply air to the upper part of the inside.

When air flows through the air supply path 5, the check valve 12 located on the downstream side is sucked by the flow pressure of the air and opens, and at the same time as the switching valve 6 is opened, the quantitative extrusion device 10 moves forward, and both check valves are opened. In order to pressurize the slip agent that has flowed out between valves 1) and 12 in advance, a certain amount of slip agent is pushed out from the open check valve 12 into the air supply path 5 and mixed with the air flowing through the air supply path 5. is supplied into casing 1. The liquid slip agent mixed with the air is supplied into the casing 1 in the form of a mist, and adheres to the inner peripheral surface of the casing 1 and evenly adheres to the interface between the casing 1 and the drain material B. Reduces the frictional force between the surrounding surface and drain material B. Therefore, there is no clogging phenomenon caused by friction between the casing 1 that is about to be pulled out and the drain material B pushed down by the pressure of the air, preventing the casing 1 and the drain material B from rising together, and moving the drain material B to the ground. You can easily pull out only casing 1 while leaving it in A. When the casing 1 is pulled out and the switching valve 6 is operated to the closed position to stop the supply of air into the casing 1, the check valve 6 is closed by the pressure of the air, and at the same time, the quantitative extrusion device 10 is closed. Return to position.

Therefore, a negative pressure is created between both check valves 1) and 12, the upstream check valve 1) opens, and the slip agent tank 8 flows from both check valves 1)
, 12, liquid lubricant flows in and prepares for the next quantitative supply. [Effects] As described above, according to the present invention, in a ground improvement method in which drain material is poured into a casing inserted into the ground, the upper end of the casing is sealed when the casing is pulled out, and air is press-fitted into the casing, the casing Since a slip agent is mixed with the air that is press-fitted inside, the slip agent is supplied to the interface between the casing and the drain material, reducing the frictional force between the two, and therefore preventing the drain material from clogging when the casing is pulled out. This makes it possible to remove only the casing without fail and eliminate joint upflow. In addition, since only the casing can be pulled out, there is no damage to the drain material, and sand columns and packed sand columns can be reliably formed in the ground.In addition, the casing can be easily pulled out, greatly increasing the work efficiency of soil improvement methods. can be improved.

Furthermore, since it is only necessary to provide a slip agent supply section in the middle of the air supply path that supplies air to the casing, it can be implemented with a simple structure.

[Brief explanation of the drawing]

The drawing is an explanatory diagram showing the ground improvement device of this invention. 1... Casing, 3... Opening/closing lid, 4... Air supply source, 5... Air supply path, 6... Shutdown Valve, 7...
...Sliding agent supply section, 8...Sliding agent tank,
10...Quantitative extrusion device, 1), 12...
... Check valve, A ... Ground, B ... Drain material.

Claims (2)

[Claims] (1) Pour drain material into the casing inserted into the ground, press air into the upper part of the casing with the upper end sealed,
A ground improvement method in which the casing is pulled out while pressurizing the drain material and the drain material is left on the ground, and the method is characterized by mixing a slip agent into the air that is press-fitted into the casing. (2) The upper end of the casing can be opened/closed and sealed, and drain material is introduced into the casing while it is inserted into the ground.In the middle of the air supply path connecting the upper part of the casing and the air supply source, a slip agent is applied to the air flowing into the casing. A ground improvement device equipped with a mixing slip agent supply section.