JPH0579765B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is used at various civil engineering and construction sites to create air bubbles in the ground in order to reduce the inflow of groundwater into the ground and facilitate the excavation when excavating highly permeable ground. This relates to the method of injection and generation. (Prior art) Conventionally, a large amount of pre-foamed foam material is injected directly into a desired location in permeable ground in a layered or planar form to create air bubbles in the gaps between soil particles. Therefore, there is a method of significantly lowering the permeability of the ground to block or stop water from permeable ground. (Problems to be Solved by the Invention) The conventional method has the following problems. Even if foamed material is injected directly into the ground, clogging occurs near the injection port, and the air bubbles are not evenly dispersed in the gaps between soil particles. A chemical must be used to maintain the shape of the foamed bubbles, which is expensive and may cause groundwater contamination. In view of the problems of the prior art, the present invention includes:
It was proposed based on the fact that the volume of a gas is inversely proportional to its pressure, and that the solubility of a gas in a liquid changes with temperature. The object of the present invention is to provide a method for dispersing bubbles safely, reliably, uniformly, and at low cost over a wide range, not only on ground where pressurized water exists, but also on ground where pressurized water exists. (Means for Solving the Problems) In order to achieve the above object, the method of injecting and generating air bubbles into the ground according to the present invention is to inject a liquid cooled to near 0°C under a water pressure higher than that of groundwater. It is configured to inject into the ground a high-pressure, low-temperature foam injection material in which gas is dissolved to a saturated or supersaturated state. Furthermore, the present invention aims to maintain the shape of air bubbles deposited in the ground.
In order to ensure stability, a foam-forming stabilizer is mixed into the high-pressure, low-temperature foam injection material. (Function) According to the present invention, a high-pressure, low-temperature foam injection material is created by dissolving a liquid cooled to nearly 0°C under water pressure higher than the water pressure of groundwater until the gas is saturated or supersaturated. When a high-pressure, low-temperature, gas-saturated liquid is substituted for the pore water between soil particles in the ground by injecting an injection material into the ground, the high-pressure, low-temperature liquid that replaced the pore water is
The temperature easily rises through heat exchange with surrounding soil particles and pore water, and decreases to the pressure of groundwater, and as a result, the gas dissolved in the high-pressure, low-temperature liquid becomes bubbles and precipitates. Distributes reliably and uniformly over a wide area in the ground. At this time, when a bubble formation stabilizer is mixed into the low-temperature bubble injection material, the bubbles deposited in the ground become closed cells with membranes and are maintained in a stable state. (Embodiments) The present invention will be described below with reference to illustrated embodiments. A pressure higher than the groundwater pressure is applied, and the water is further cooled to near 0°C and aerated to create high-pressure, low-temperature bubbles and injection materials in which gas is dissolved in the same liquid in a saturated or supersaturated state. Note that the liquid used is the above-mentioned water or a liquid having viscosity, and in particular, a liquid having viscosity is used in the ground where the flow rate of underground water is high. In addition, non-toxic gases such as air and carbon dioxide are used. Further, the cooling temperature is determined by the groundwater temperature, the amount of air required, etc., and the pressure to be applied is further determined by the porosity of the ground, the pressure of the groundwater, the required air, etc. Next, the high-pressure low-temperature foam injection material is applied to the ground under pressure water using a method similar to the conventional ground injection method.
Alternatively, when the required amount is injected into the required areas of the ground below the free water surface in a layered or planar form, the injection material is a high-pressure, low-temperature liquid with gas dissolved to a saturated or supersaturated state, so the pores between soil particles can easily replaced by The high-pressure, low-temperature liquid that replaces the pore water between soil particles in this way exchanges heat with the surrounding soil particles and pore water, and easily rises in temperature, since the temperature of groundwater is usually around 16°C. , the pressure decreases to the pressure of groundwater. As is clear from Table 1 below, the solubility of gas in liquid decreases as the temperature rises. At the same time, the gas bubbles are precipitated as bubbles, and at the same time, the volume expands due to the pressure reduction of the high-pressure and low-temperature bubble injection material, and the bubbles are reliably and uniformly dispersed over a wide range, resulting in the formation of permeable ground. The water-blocking and water-stopping effects are significantly improved. In Table 1 below, 1 atmosphere of gas is 1
A table is shown in which the volume when dissolved in cm ³ of water is converted to the volume at 0° C. and 1 atm.

[Table] Furthermore, by mixing a small amount of a bubble forming stabilizer into the high-pressure, low-temperature cell injection material, the bubbles precipitated in the ground become independent closed cells with membranes. (Effects of the Invention) According to the present invention, as described above, a high-pressure, low-temperature bubble injection material is produced by dissolving a gas in a liquid cooled to near 0°C to a saturated or supersaturated state under water pressure higher than the water pressure of groundwater. By injecting the same injection material into the ground, it can be used not only under the free water surface, but also under the ground.
It can easily replace the interstitial water between soil particles under groundwater, and as the pressure of the injection material decreases and the temperature rises, air bubbles precipitate and diffuse, ensuring that the air bubbles spread over a wide range into the ground. , and is uniformly dispersed, and as a result, the water-blocking and water-stopping effects of permeable ground can be significantly improved. The method of the present invention can be applied not only to the ground under free water but also to the ground under pressure water.
Particularly in the ground below the free water surface, a large amount of air bubbles can be interposed extremely efficiently. Furthermore, since the high-pressure, low-temperature bubble injection material can use water as the liquid, it is inexpensive and has no risk of causing pollution. In the method of claim 2, by mixing a bubble forming stabilizer into the high-pressure and low-temperature bubble injection material, the bubbles precipitated in the ground become stable closed cells with a membrane, thereby blocking and stopping water in the ground. This can further improve the effect.

Claims (1)

[Claims] 1. A high-pressure, low-temperature foam injection material in which gas is dissolved to a saturated or supersaturated state is injected into the ground in a liquid cooled to nearly 0°C under water pressure higher than the water pressure of groundwater. Inject air bubbles into the ground,
How to generate it. 2. The method of injecting and generating air bubbles into the ground according to claim 1, characterized in that a bubble formation stabilizer is mixed into the high-pressure and low-temperature air injection material.