JPS6117970B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for consolidating soft ground, and in particular,
This article relates to a ground fixing method that homogeneously and firmly consolidates or stops water in soft or leaky ground. Soft ground is usually formed by alternating layers of coarse-grained soil and fine-grained soil, but this cannot be uniformly consolidated by injecting a consolidation agent into the soil. is necessary. Due to the recent environmental conservation and water quality conservation issues in construction work, it is desired from the viewpoint of pollution prevention that the injected water glass grout solidify reliably at the point where it is injected without deviating from the injection area. The present invention involves inserting an injection pipe consisting of multiple pipes into the ground, and injecting a plurality of injection materials having different consolidation times through the injection pipe. It forms a film with a packer effect by filling the gap between the surface and the ground, and also forms a consolidated layer mainly consisting of veins that fills the interface between rough layers and layers. The injection material is injected into the region where the injection material with the shorter consolidation time has already been injected by breaking the membrane. The injection material that takes longer to solidify does not deviate from the area around the injection tube or from the rough layer, so it can reliably penetrate and solidify the injection target area. Specifically, the present invention inserts multiple pipes including an inner pipe and an outer pipe into the ground, moves the multiple pipes to change the injection stage, and passes through a plurality of pipes in the multiple pipes, thereby increasing the consolidation time. In a composite injection method in which a plurality of injection materials with different values are injected, (A) the tip of the inner tube is formed shorter than that of the outer tube, and the tip of the multiple tube serves as a mixing chamber;
Among multiple injection materials with different solidification times, the injection material with a shorter solidification time has a solidification time of 30 seconds or less, and the base compound solution and reactant compound solution are passed through multiple tubes in the multi-tube system. (B) The injection material with a longer solidification time is sent to the ground through the outlet at the bottom of the outer tube of the multi-layered tube. By injecting from the outlet and switching between the injection material with a shorter consolidation time and the injection material with a longer consolidation time, these multiple injection materials can be injected into the ground at different times. (C) The injection material with the shorter consolidation time has an injection depth of 1.
The injection amount is 1 or more per m, which forms a filler with a Packer effect in the void around the injection pipe, and fills the parts that are likely to deviate, and the injection material with a longer solidification time has a shorter solidification time. The present invention relates to a ground injection method characterized in that the filling material is broken and penetrated into the area into which the first injection material has been injected. To explain in more detail, first, multiple pipes are installed in a predetermined position in the ground, and then the injection material with a shorter consolidation time is injected at the tip of the multiple pipe to fill the void around the injection pipe. After forming an effective seal, the longer setting time injection material is injected to complete the lowermost stage injection. Next, the multiple tubes are pulled up to a predetermined position, and the injection material with the shorter setting time is injected to fill the voids around the tubes and the rough layer around them that were created by moving the multiple tubes. After that, the injection material with a longer setting time is allowed to penetrate. Repeat the injection while raising the stage in the same manner. As mentioned above, it is not possible to multiple times inject into the same area in the ground the injection material with a shorter consolidation time that can form a film with the Patzker effect and the injection material with a longer consolidation time that can penetrate between soil particles. This is effectively possible by using a tube. In other words, by using a pipe line formed by the inner and outer walls of a circular pipe line, it is possible to effectively combine injection materials with different consolidation times and perform composite injection into the ground. I can do it. In this case, for the combination of the injection material with a shorter setting time and the injection material with a longer setting time, the injection material with a longer setting time and a rapid setting reactant are respectively delivered through the conduit,
Alternatively, the main material compounded liquid and the reactant compounded liquid are sent through the pipes respectively, and are combined at the tip of the multi-tube to form the injection material with a shorter solidification time, and then injected, and then The injection material may be injected through either of the above conduits, or the components constituting the injection material with a longer setting time may be delivered through each conduit and merged at the tip. An injection method can be used. In the above, Y-shaped tubes can be connected to the aboveground parts of multiple conduits in a multi-pipe, and the components constituting each injection material can be merged. The operation can be adjusted to interrupt, continue, or merge the injection of the injection material, or to combine or interrupt the injection of the components constituting the injection material. In this way, in order to switch between injections with different solidification times in the present invention, as shown in FIG.
These injection materials can be superimposed and injected. The following methods are conventionally known as methods for consolidating soft ground. (1) Rod injection method This method uses an aqueous solution of a reactant or a suspension containing cement material (liquid A) as a solidifying agent, and an aqueous water glass solution (liquid B). This is a method of injecting into the ground while merging the rod, but a gap is created between the boring rod and the ground, and the cement can spray out onto the ground surface from this gap, or the injected liquid can escape through the rough layer. Therefore, it is difficult to consolidate into fine-grained soil layers or within a specified range. (2) Double pipe injection method This uses water glass as the A liquid and a gelling agent as the B liquid to join together at the tip of the double pipe installed in the ground and solidify in a short gelation time. This is a method of injecting a blended grout. According to this method, because the gelation time is short, it is possible to prevent the grout from spewing out above the ground around the rod, but because the gelation time is short, it can only solidify the coarse layer in veins and penetrate between the soil particles. I can't do it. For this reason, during excavation, the spring water soil is likely to collapse. The present invention consolidates these complex coarse-grained soil layers and fine-grained soil layers into an integrated whole.
The object of the present invention is to provide a method for consolidating soft ground that forms a homogeneous, watertight, and highly strong consolidated ground, which solves the drawbacks of the above-mentioned conventional methods. By using the following method, the present invention has been able to achieve effects that cannot be obtained with conventional injection methods. (1) Combining multiple injection materials with different setting times. Examples of injection materials include: Suspension type grout that contains cement or clay as an active ingredient, or grout that has an accelerating agent added to it.Grout that contains suspended matter and the entire liquid becomes a gel, such as cement/water glass grout or clay/water glass grout. Water glass grout containing water glass and a reactive agent Resin-based grout containing a synthetic resin and a reactive agent that polymerizes after a certain period of time Injection within 30 seconds as the injection material with the shorter setting time among injection materials with different setting times The application of the material is particularly effective for creating an effective gel film in the gap between the injection pipe and the ground to form a membranous seal with a Packer effect. This not only prevents the injection liquid from flowing through the injection pipe and spewing out above the ground when injection liquid with a long solidification time is subsequently injected, but also prevents the injection liquid from forming a gel film at the position of the injection liquid outlet. rupture, allowing the injected solution with a long consolidation time to penetrate into the soil layer at that stage. In addition, when a compounded liquid that gels within 30 seconds merges from the Y-shaped tube at the upper end of the rod during rod injection, it tends to clog in the rod and become impossible to inject. If they merge at the tip, it is possible to use grout with a short setting time. If the solidification time of this injection material exceeds 1 minute, the injection material will spray out from around the injection pipe to the above ground, making it difficult to create a tight seal of gel film around the injection pipe, and it will be difficult to continue. If a material that takes a long time to solidify is injected, the packer effect will be insufficient and the material will spray out from around the injection pipe onto the ground surface, or as in the case of rod injection, the material will spread unspecifiedly around the rod, and the material will not reach the specified stage. It tends to be difficult to inject the liquid accurately. However, if a predetermined amount of injection material is injected within 30 seconds in advance, even if the injection material is injected for more than 1 minute, it can be injected into the ground without deviation. In the above, the injection amount of the injection material with the shorter consolidation time is required to be one or more injections per 1 m of injection depth. If it is less than 1, it becomes impossible to form a seal having a Packer effect around the injection pipe.
In order to fill up the Packer effect around the injection pipe and the loosened part of the ground around the injection pipe when installing the injection pipe, it is usually desirable to have an injection rate of 5 or more per 1 m of injection depth. In addition, as the water glass grout containing water glass and a reactant in the above, examples of the reactant include esters (ethyl acetate, ethylene gol acetate, triacetin, ethylene carbonate, etc.), aldehydes (glyoxal, etc.), amides (formamide, etc.). ), acids (phosphoric acid, sulfuric acid, etc.), salts (bicarbonate, bisulfate, phosphate, etc.), water glass grout that gels in alkaline, neutral, and acidic regions using any reactive agent such as carbon dioxide gas. can be used. In addition, water glass, alkali (sodium carbonate, sodium bicarbonate, caustic soda, magnesium oxide, and other alkaline salts) are added to an acidic compound solution that can gel itself and has a long gelation time, which is obtained by adding water glass to an aqueous solution of an acidic reactant. etc.), cement (Portland cement, blast furnace cement, alumina cement, etc.), lime, etc. can be combined to obtain a grout having a short gelation time. Such grouts are very effective in the present invention. In addition, resin-based grouts include those that polymerize by adding a polymerization agent, such as acrylic, urea-based, and lysine-based grouts, or those that solidify by reacting with water, such as urethane-based grouts. I can use things. However, in the above, in order to form an injection material with a shorter solidification time, a reactant is added to the main material mixture. In the above, the main material mixture refers to a water glass mixture, a mixed mixture of water glass and a reactant, or a mixture that solidifies itself, such as a cement suspension. As water glass, molar ratio (SiO ₂ /M ₂ O):
1.5 to 5.0 Refers to an alkali metal salt of silicic acid in any molar ratio, including liquid water glass, anhydrous water glass, hydrous water glass, crystalline water glass, etc., or a mixture of an alkali metal salt of silicic acid and silicic acid. (2) Multiple injection materials with different consolidation times are injected into the ground by passing through channels in injection pipes made up of multiple pipes. In this case, each injection material may be formed before entering the multiple pipes, or the components constituting the injection material may pass through the channels in the injection pipes to the tip of the injection pipe or to the ground from the tip of the injection pipe. A predetermined grout may be formed by discharging the grout into the grout and then merging the grout. Here, multiple pipes refer to double pipes, triple pipes, or pipes in which several pipes are installed in parallel. In addition, the discharge port for the injection material into the ground is opened at the tip of the injection pipe or on the side wall of the outer pipe, but both the injection material with a shorter consolidation time and the injection material with a longer consolidation time are the same. is injected from the outlet. (3) When injecting, use the injection material that takes a shorter time to solidify to form a filler with a packing effect in the gap between the injection pipe and the ground, and at the same time fill the gap in the ground where the injection material that takes a longer time to solidify is likely to slip out. After filling, the filling material with a long setting time is broken and the filling material with a short setting time is injected into the area into which the filling material with a short setting time has been injected. For this purpose, a plurality of injection materials having different solidification times are injected while being switched, so that the timing of injection of these injection materials is staggered. Here, staggering the timing of injecting a plurality of injection materials having different setting times means not injecting a plurality of injection materials having different setting times at the same time. Alternatively, the injection material with a longer solidification time is discharged from between the inner tube and the outer tube, and at the same time, the mixture containing a quick-setting material that quickly solidifies the injection material with a longer solidification time is combined from the inner tube. After injecting the rapidly setting material, the injection of the rapidly setting material from the inner pipe is interrupted and the injection of the material having a longer setting time is switched to injection. In the above, a plurality of injection materials having different solidification times may be injected while changing the injection stage. In any case, by injecting the injection material with a shorter consolidation time of 1 or more, preferably 5 or more per 1 m of injection depth, the voids around the injection pipe and the parts of the surrounding ground that are likely to deviate can be filled. Thereafter, the injection material with a longer setting time permeates into the part where the injection material with a shorter setting time has not penetrated, and both are overlapped and injected. In the above, the combination of a plurality of injection materials having different solidification times is combined using two or more mixtures selected from a water glass mixture, a reactant mixture, and a mixed mixture of water glass and a reactant, and the injection When injecting the liquids, the above-mentioned plurality of blended liquids are sent to the multiple pipes through at least one combination adjustment device, and the combination adjustment device is operated to inject and solidify the injection material with the shortest solidification time. Injection can be performed by switching the injection of the injection material that takes longer time to set. For example, as shown in Figure 1, the water glass mixture reacts with the water glass to form the injection material with the shorter setting time, and the reactant mixture reacts with the water glass to form the injection material with the longer setting time. The reactant mixture liquids forming the materials are respectively supplied. The supply pipe is connected to the double pipe containing the two pipe lines through at least one combination adjustment device, and the combination adjustment device is operated to select the injection material having the shorter setting time and the setting time. It is possible to switch the injection of the longer injection material. In the above, the combination regulating device is an injection pump or a control valve. Fig. 1 shows an example of an injection device for carrying out the present invention, which enables injection into the ground by automatically combining injection materials having different consolidation times according to the ground conditions and injection conditions. It becomes possible. To explain in more detail, when a combination of multiple grouts is injected into the ground, the condition of the injection into the ground is measured using measuring instruments such as the injection pressure gauge 5 flow meter 6 or the injection depth gauge 7'. The information thus obtained is transmitted from the measuring instrument to a combination adjustment device such as the infusion pump 2 or control valve 14 via a controller 8 containing a sequence circuit, and the combination adjustment device receives commands from the controller 8. The grout materials can be combined in any form and automatically combined according to the ground injection situation. In the above, the controller 8 commands the elevator 7 based on the information obtained from the depth gauge 7' to move the injection tube to a predetermined depth and inject a predetermined amount of the injection material with a shorter solidification time. It is possible to inject a fixed amount of the injection material with a longer solidification time to complete the injection of that stage, and then give an instruction to automatically operate the next stage, or to give an instruction to the compounded liquid manufacturing equipment. Any combination liquid can be manufactured. Also, with such a device, the ratio of the injection amount of the injection material with a shorter consolidation time to the injection material with a longer consolidation time at each depth can be set based on information obtained in advance through a survey. By doing so, the specified injection can be performed automatically based on the instructions from the controller. By using the above method, if the injection material with a shorter consolidation time is injected into the ground first, not only the rough voids in the ground but also the gaps between the injection pipe and the ground can be filled with the material with a shorter consolidation time. If the area is filled with the solidified material of one of the injection materials and then the injection material with a longer setting time is injected into that area, the gap or gap is already filled and consolidated with the injection material with a shorter setting time. Therefore, the injection material with a longer consolidation time does not escape into the ground surface or into the voids, and completely penetrates into the fine-grained soil layer. After injecting a predetermined amount, the injection tube can be pulled up to an appropriate height, the injection described above can be performed again, and the injection operation described above can be repeated many times while pulling up the injection tube. The method of the invention can be carried out perfectly. Example 1 Using the method shown in Figure 1, a double pipe was installed in the ground consisting of a gravel layer and a coarse sand layer to a depth of GL-10, and liquid I (passed through the outer pipe) and liquid having the following composition were (passed through the inner tube) into the same amount at the tip of the double tube, and after 20 injections, the injection of the liquid was stopped and only the liquid was poured.
After 100 injections and completion of injection at the lowest stage, the double tube was raised 0.5 m and the same process was repeated until GL-3 m was injected.

[Table] In the above, Denka Kagaku Kogyo Denka ES (a molten mixture of main components CaO, Al ₂ O ₃ and CaSO ₄ ) was used as a commercially available cement quick setting agent. Composition of commercially available cement quick-setting agents in liquids: Denka ES 10Kg ES Setta 0.25Kg When the liquids are combined, they gel in about 20 seconds. As a result of the excavation investigation, a solid body with a diameter of approximately 1 m had been formed around the injection pipe in both the coarse sand ground and the fine sand ground. For comparison, we excavated after injecting 120 ml of liquid into each 0.5 m area, but found that almost no solids were found in the coarse sandy ground, and only irregularly formed solids were found in the sandy ground. I found out.

[Brief explanation of the drawing]

FIG. 1 shows a configuration diagram of a specific device for carrying out the construction method of the present invention. 1, 1', 1''...Compounded liquid blending device, 2, 2',
2″...Infusion pump, 3...Multiple outer tube, 3'...
Multiple tube inner tube, 5, 5', 5''...pressure measuring device, 6,
6', 6''...Flow rate measuring device, 7...Elevator, 7'...
...Injection tube depth gauge, 8...Controller, 9...Inflow part from inner tube to injection tube tip, 9'...Injection tube tip, 10, 10', 10''...Pressure gauge to controller Information notification circuit, 11, 11', 1
1''...Information notification circuit from the flow meter to the controller, 12...Information notification circuit from the injection depth meter to the controller, 13, 13', 13''...Instruction circuit from the controller to the injection pump, 14...
Injection material combination adjustment device, 15...Instruction circuit from the controller to the injection material combination adjustment device;
16... Indication circuit from the controller to the elevator, 17, 17', 17''... Indication circuit from the controller to the compounded liquid blending device, A: Rapid setting reaction compounded liquid, B: Main material compounded liquid, C: Reactant mixture liquid.

Claims (1)

[Claims] 1. Insert a multiple tube including an inner tube and an outer tube into the ground, and move the multiple tube to change the injection stage while passing through a plurality of pipes in the multiple tube to determine the consolidation time. In a composite injection method in which a plurality of different injection materials are injected, (A) the tip of the inner tube is formed shorter than that of the outer tube, and the tip of the multiple tube serves as a mixing chamber;
Among multiple injection materials with different solidification times, the injection material with a shorter solidification time has a solidification time of 30 seconds or less, and the base compound solution and reactant compound solution are passed through multiple tubes in the multi-tube system. (B) The injected material having a longer solidification time is sent to the ground through the outlet at the bottom of the outer tube of the multi-layered tube, and is formed by converging in the mixing chamber. By injecting from the outlet and switching between the injection material with a shorter consolidation time and the injection material with a longer consolidation time, these multiple injection materials can be injected into the ground at different times. (C) The injection material with the shorter consolidation time has an injection depth of 1.
The injection amount is 1 or more per m, which forms a filler having a Packer effect in the void around the injection pipe, and fills the parts that are likely to dislodge, and the injection material with a longer solidification time has a shorter solidification time. A ground injection method characterized by breaking the filler and allowing it to penetrate into the area into which the filler has been injected.