JP2005016127A - Method of injecting injection liquid into ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of injecting an injection liquid into the ground while rationally and efficiently setting injection conditions according to the injected state of the injection liquid. <P>SOLUTION: Solidification characteristics when injecting a chemical solution into the ground are evaluated to determine the mixing of the chemical solution suitable for the object ground 1. A plurality of injection holes 2 for injecting the chemical solution are bored in an object region of the ground 1. While monitoring the injection speed, the chemical solution is injected into the ground 1 from the injection holes 2 at constant injection pressure within a range not to form a cleavage in the ground 1. When the injection speed is lowered to a prescribed value in the state of holding the injection pressure within the range not to form the cleavage in the ground 1, the injection of the chemical solution is terminated, and the executed chemical solution 5 infiltrating into the ground 1 is cured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for injecting an injection solution into the ground, which is suitable when applying a slow-binding chemical solution to a target ground in the ground improvement method.
[0002]
[Prior art]
Conventionally, a method of injecting a chemical solution into the ground to be improved has been generally known for ground improvement.In particular, the importance of a method of penetrating and injecting a slow-setting chemical solution with a long gel time into the ground has been recognized. Patent Document 1 and Patent Document 2 devise a ground injection method at a low injection speed in consideration of using a slow-release chemical solution having a long gel time. In these ground injection methods, in order to ensure that the chemical solution penetrates into the target improvement range, it is essential to maintain the fluidity of the chemical solution during the injection period, and to apply the appropriate gel time chemical solution to the appropriate pressure and time. It is important to inject with.
[0003]
In addition, as shown in Patent Document 3, in the ground injection method using a chemical solution having an extremely long gel time in consideration of the creation of a large-diameter improved body, it is important to set a more precise gel time, that is, to properly mix the chemical solution.
Therefore, in order to assist in the proper formulation of the chemical solution, it is conceivable to apply a method for measuring the solidification characteristics of the chemical solution as shown in Patent Document 4.
[0004]
[Patent Document 1]
JP 2000-045259 A
[Patent Document 2]
JP 2002-363967 A
[Patent Document 3]
JP 2003-317436 A
[Patent Document 4]
JP 11-37997 A
[0005]
[Problems to be solved by the invention]
However, in order to measure the solidification characteristics of chemicals, the actual injection conditions are modeled using a large-scale test device, so a huge amount of on-site samples and chemicals are required to conduct the test. It is difficult to carry out the test.
In addition, when the ground conditions and the execution conditions such as the injection pressure are uncertain, the reliability of the test results is low even if the test is performed under the predicted conditions.
In this way, in reality, it is difficult to even evaluate the gel time in the chemical solution, which is the most basic of the injection plan, and in order to set so that a chemical solution with an appropriate gel time can be injected at an appropriate pressure and time according to the enforcement conditions There are many challenges.
[0006]
In view of the above circumstances, an object of the present invention is to provide a method for injecting an injection solution into the ground, which injects the injection solution into the ground while setting injection conditions reasonably and efficiently according to the injection state of the injection solution. It is said.
[0007]
[Means for Solving the Problems]
The method for injecting an injection solution into the ground according to claim 1 is a method for injecting an injection solution into the ground for injecting an injection solution suitable for improving the ground, and solidifying when the injection solution is injected into the ground. The first step of evaluating the characteristics and determining the composition of the infusion solution suitable for the target ground, and the infiltration range with a spacing interval that overlaps a part of the infiltration range when the infusion solution is injected into the ground The second step of drilling a plurality of injection holes vertically so as to cover the target area of the ground, and the injection rate from the injection hole to the ground and splitting the ground while monitoring the injection speed The third step of injecting at a constant injection pressure in a non-existing range, and the injection is terminated when the injection rate drops to a predetermined value, curing the infusion solution that has penetrated the ground, and the infiltration range does not overlap From the other injection hole to the ground, the same as the third step The fourth step of injecting the injection solution according to the above procedure, the third step and the fourth step are repeated, and the fifth step of injecting the injection solution into the ground from all the injection holes is configured. It is a feature.
[0008]
The method for injecting the injection liquid into the ground according to claim 2 is the third step, injecting the injection liquid into the ground while monitoring the injection pressure, increasing or decreasing the injection flow rate of the injection liquid, A constant injection pressure is maintained by keeping the absolute value of the rate of change in pressure at the time of injection within a predetermined value calculated from the change over time.
[0009]
The method of injecting the injection liquid into the ground according to claim 3 is a fourth step in which the injection liquid that has penetrated the ground is cured and solidified while the liquid pressure is kept constant in the injection hole where the injection of the injection liquid has been completed. It is characterized by doing.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method for injecting an injection solution into the ground according to the present invention will be described in detail with reference to FIGS. The method of injecting the injection liquid into the ground according to the present invention is performed by monitoring the injection speed of the injection liquid whose composition has been determined after evaluating the solidification characteristics at a constant pressure within a range that does not cause splitting of the ground. The injection is terminated when the injection rate drops to a predetermined value, and the injection is repeated in the same procedure in the ground area where the injection solution has not penetrated, so that the ground is not split. Effective injection is performed.
In this embodiment, a slow-setting chemical solution that loses gel time, that is, fluidity and takes a long time until the viscosity rapidly increases is used as an injection solution to be injected into the ground. Any injection solution may be used as long as it is suitable for ground improvement.
[0011]
The injection of the chemical solution 4 to the ground 1 uses an injection device 6 that can inject the chemical solution 4 having a composition suitable for ground improvement into the target ground 1 under pressure, and in this embodiment, The injection device 6 having an injection pressure control mechanism 9 capable of controlling the injection pressure is used.
[0012]
As shown in FIG. 1, the injection device 6 includes a pressurizing tank 7 that stores a pressurized chemical solution 4, a compressor 8 that pressurizes the inside of the pressurizing tank 7, and the pressurizing tank 7. An injection pressure control mechanism 9 that controls the amount of injection pressure of the chemical solution 4 by controlling the internal pressure, a supply device 10 for supplying the chemical solution 4 to the pressurizing tank 7, and an injection hose that injects the chemical solution 4 into the ground 1. 14 is provided. The replenishing device 10 includes a replenishment control mechanism 12, a liquid amount detector 13, and a liquid storage tank 11 that stores the chemical liquid 4 for replenishment.
[0013]
The injection pressure control mechanism 9 attached to the pressurizing tank 7 controls the replenishing device 10 so as to maintain the liquid level in the pressurizing tank 7 at a desired pressure, and replenishes the chemical liquid 4. The pressure drop in the pressurization tank 7 and the pressure increase in the pressurization tank 7 accompanying the replenishment of the chemical solution 4 are detected, and the compressor 8 is controlled to control the pressure in the pressurization tank 7. It is controlled so as to be kept constant at all times.
[0014]
That is, the injection device 6 continues the chemical solution 4 in the pressurization tank 7 to the ground 1 via the injection hose 14 while keeping the pressure of the pressurization tank 7 constant by the injection pressure control mechanism 9 as described above. The chemical solution 4 having a constant flow rate is injected at a constant rate by injecting under pressure.
The amount of injection pressure to the ground 1 is determined by the pressure in the pressurizing tank 7 controlled by the injection pressure control mechanism 9. Therefore, the injection pressure amount of the chemical solution 4 can be easily adjusted by the injection pressure control mechanism 9, and the chemical solution 4 is grounded while maintaining a desired injection pressure amount by maintaining the pressure in the pressurizing tank 7. 1 can be stably and continuously injected.
[0015]
Note that the injection device 6 is not necessarily limited to the configuration including the injection pressure control mechanism 9 as described above, and it is possible to continuously pressurize and inject the chemical solution 4 at a constant flow rate to the ground 1 at a constant speed. Any of these may be used. In addition, the adjustment method of the chemical | medical solution 4 injection | pouring pressurization amount in this case is explained in full detail by the injection | pouring method of the chemical | medical solution to the ground shown below.
[0016]
A method of injecting the chemical solution into the ground for injecting the chemical solution 4 into the target ground 1 using the injection device 6 described above will be described below.
[0017]
(First step)
In a 1st process, the solidification characteristic at the time of inject | pouring the said chemical | medical solution 4 to the ground 1 is evaluated, and the mixing | blending of the chemical | medical solution 4 suitable for the ground 1 made into object is determined. Hereinafter, an example of a method for evaluating solidification characteristics will be described in detail, but the evaluation method is not necessarily limited to this.
[0018]
In evaluating the solidification characteristics of the chemical solution 4, first, a penetration test apparatus (not shown) that models the ground 1 into which the chemical solution 4 is to be injected is manufactured. The permeation test apparatus is manufactured to the same scale (same length) as the actual permeation distance and large enough to perform the laboratory test.
Next, from the ground configuration of the target ground 1, the infiltration shape and water permeability of the chemical solution 4 (mainly the water permeability coefficient and the layer thickness of the water permeable layer) are predicted. The injection rate q in the working process is predicted from the structure, dimensions, etc. of the injection hose 14 at the time of injection.
And the chemical | medical solution 4 is inject | poured with said injection | pouring speed | rate q with respect to said penetration test apparatus. In this case, the injection rate q is changed according to the following equation during the test when the chemical solution 4 penetrates in a layered manner in a one-dimensional penetration test using a cylindrical container, for example.
[0019]
q = q ₀ r ₀ / (L + r ₀ )
q: Injection rate at an arbitrary time during the test period
q ₀ : Injection rate at the start of the test corresponding to the injection rate at the working site
L: Length of penetration of chemical
r ₀ : Equivalent cavity radius of injection hole
[0020]
The chemical solution 4 is injected at the above speed, and the injection of the chemical solution 4 is stopped when the chemical solution 4 penetrates to the target penetration distance. Subsequently, the gel time of the chemical | medical solution 4, the strength deformation characteristic of the solidified soil, etc. are measured about the specimen (mixture of soil and chemical | medical solution) of the filling part of the chemical | medical solution 4 of the outflow side of an osmosis | permeation test apparatus. Moreover, the chemical | medical solution 4 and the non-penetrating chemical | medical solution 4 after making the soil penetrate | infiltrate a predetermined length measure the property (pH) change of the chemical | medical solution 4, and measure the property change of solidified soil.
Based on the solidification characteristics of the chemical solution 4 evaluated by the test method described above, the composition and gel time of the chemical solution 4 are determined.
[0021]
(Second step)
In the second step, a plurality of injection holes 2 for injecting the chemical solution 4 are drilled in the target area of the ground 1.
[0022]
As shown in FIG. 2, the injection hole 2 is provided with a spacing L so that a part of the permeation range 1 a overlaps when the chemical solution 4 is injected into the ground 1, so that two orthogonal x and y directions are provided. A plurality are arranged in parallel. The injection holes 2 are not necessarily arranged in parallel as described above, and have a separation interval L such that a part of the permeation range 1a overlaps when the chemical solution 4 is injected from each of the adjacent injection holes 2. And if the penetration | infiltration range 1a is arrange | positioned so that the whole object area | region of the ground 1 can be covered, the arrangement | positioning shape and quantity may be any.
The permeation range 1a of the chemical solution 4 may be appropriately set as a target range, but the most efficient in one injection operation based on the evaluation result of the solidification characteristics of the chemical solution 4 performed in the first step. A typical permeation range 1 may be estimated, and the separation interval L and quantity of the injection holes 2 may be determined according to the permeation range 1a.
[0023]
(Third step)
In the third step, while monitoring the injection rate, the chemical solution 4 is injected from the injection hole 2 into the target ground 1 at a constant injection pressure in a range that does not cause the ground 1 to split.
[0024]
At this time, the constant injection pressure amount of the chemical solution 4 to the target ground 1 is determined based on the evaluation result relating to the solidification characteristics of the chemical solution 4 evaluated in the first step. And In this embodiment, since the injection device 6 includes the injection pressure control mechanism 9, the injection of the chemical solution 4 is performed while automatically adjusting the injection pressure amount as needed so that the injection pressure does not deviate from the determined amount. is there.
However, when using the injection device 20 that is not provided with the injection pressure control mechanism 9, it is necessary to monitor the injection pressure of the chemical solution 4 and perform the injection of the chemical solution 4 while adjusting the pressure so as to keep it constant.
[0025]
Below, while showing the injection pressure measuring device 15 which can monitor the injection pressure of the chemical | medical solution 4, the adjustment method of the injection pressure using this injection pressure measuring device 15 is explained in full detail.
As shown in FIG. 3, the injection device 20 injects the liquid storage tank 11 that stores the chemical liquid 4, the injection hose 14 that supplies the chemical liquid 4 to the injection hole 2, and the chemical liquid 4 in the liquid storage tank 11. A pump 21 for feeding to the hose 14 is provided.
[0026]
As shown in FIG. 3, the injection pressure measurement device 15 includes an injection pressure detection unit 16 and a pressure measurement device 18. The injection pressure detector 16 is disposed inside the injection hole 2, and a pressure transducer 17 is provided at the tip thereof. The pressure converter 17 detects the injection pressure of the chemical solution 4 injected from the injection hose 14 inside the injection hole 2 using a foil strain gauge as a conversion element. The injection pressure detection unit 16 including these pressure transducers 17 is electrically connected to a pressure measurement device 18 disposed on the ground, and the pressure measurement device 18 is based on an electrical signal from the injection pressure detection unit 16. Thus, the change over time in the injection pressure in the vicinity of the pressure transducer 17 is measured.
Note that the injection pressure measuring device 15 is not necessarily limited to the above-described configuration, and may be capable of grasping the injection pressure amount of the chemical solution 4 inside the injection hole 2 and the change rate of the injection pressure amount over time. Any of them may be used.
[0027]
In these injection pressure measurement devices 15, the pressure measurement device 18 is disposed on the ground, and the injection pressure detection unit 16 is inserted inside the injection hole 2. At this time, the injection hole 2 is filled with the seal grout 3, and the injection pressure detection unit 16 is embedded in the seal grout 3 together with the injection hose 14 of the injection device 20. The injection hose 14 is provided with a plurality of chemical solution injection valves 22 on its side surface, and the chemical solution 4 is injected from the chemical solution injection valve 22 into the injection hole 2. Sixteen pressure transducers 17 are arranged at a height position close to the chemical liquid injection valve 22.
[0028]
The method of measuring the injection pressure using the injection pressure measuring device 15 arranged in this way is that when the chemical solution 4 is injected into the ground 1 from the injection hose 14, the chemical solution 4 injected from each chemical injection valve 22 is sealed. It penetrates into the grout 3 and the ground 1, and the chemical solution 4 reaches the injection pressure detector 16. The injection pressure detection unit 16 directly measures the injection pressure of the chemical liquid 4 injected from the chemical liquid injection valve 22 of the injection hose 14 near the chemical liquid injection valve 22 and inputs it to the pressure measuring device 18. Then, the pressure measuring device 18 measures the change over time of the injection pressure in the injection pressure detection unit 16 based on the electrical signal corresponding to the measured value of the injection pressure.
[0029]
Therefore, the method for adjusting the injection pressure amount of the chemical solution 4 is based on the case where the absolute value of the rate of change deviates from the predetermined fluctuation range using the change over time of the injection pressure of the chemical solution 4 in the injection hole 2 measured by the above-described method. In addition, a constant injection pressure amount is maintained by adjusting the injection flow rate of the chemical solution 4.
By the way, the configuration using the absolute value of the rate of change over time related to the injection pressure of the chemical solution 4 occurs, for example, when splitting occurs in the ground 1 during the injection operation of the chemical solution 4, after the injection pressure increases immediately before the splitting occurs. In addition, since a large amount of the chemical solution 4 flows instantaneously into the split, the injection pressure is instantaneously reduced, and the ratio (change rate) of the injection pressure to the injection time (change over time) is the same as that of the osmotic injection before the split occurs. It is well below the rate of change in the category. In addition, when the split pulse does not progress, a phenomenon occurs in which the injection pressure is stabilized again.
Therefore, if the absolute value of the ratio (change rate) of the change in injection pressure with respect to the injection time (rate of change) does not exceed the maximum value of the rate of change in the osmotic injection category before the split occurs, the occurrence or occurrence of splitting occurs. The expansion of cracks can be suppressed.
[0030]
Here, the absolute value of the change rate of the injection pressure that does not cause splitting in the target ground 1 is determined using the injection pressure measuring device 15 when evaluating the solidification characteristics of the chemical solution 4 in the first step. It is determined by measuring the relationship between the injection time until the splitting occurs and the injection pressure, and grasping the maximum value of the change rate of the injection pressure over time before the splitting occurs.
[0031]
The method of maintaining a constant injection pressure amount by adjusting the injection flow rate of these chemical solutions 4 is adjusted by adjusting the injection flow rate of the chemical solution 4, for example, as shown in FIG. The control device 19 that controls the injection flow rate of the chemical solution 4 that is linked to both of them may be used.
The control device 19 is communicatively connected to both the pressure measuring device 18 and the pump 21 of the injecting device 20, and the injecting pressure amount fluctuates by a predetermined amount based on the change over time of the injecting pressure input from the pressure measuring device 18. When deviating from the range, the pumping flow rate of the chemical solution 4 of the pump 21 is adjusted, and the injection flow rate of the chemical solution 4 is adjusted.
[0032]
(Fourth process)
In the fourth step, the injection of the chemical solution 4 is terminated when the injection speed is reduced to a predetermined value in a state where the injection pressure is maintained within a range that does not cause the ground 1 to split, and penetrates the ground 1 The finished chemical solution 5 is cured.
In parallel with this, the chemical solution 4 is injected into the target ground 1 from the other injection hole 2 that does not overlap the infiltration range with the applied chemical solution 5 in the same procedure as the third step.
[0033]
Here, the injection speed as a reference when the injection of the chemical solution 4 to the ground 1 is terminated is the construction condition such as the case where there is a water conveyance gradient (groundwater flow or the like) that is concerned about the target ground 1 or its numerical value. Although it depends on the purpose of injection of the chemical solution 4, it is determined with reference to the time when the numerical value falls within the range of ¼ to 1/10 of the initial injection rate of the chemical solution 4.
As shown in FIG. 4, when the viscosity of the applied chemical solution 5 that has penetrated into the ground 1 starts to rise to some extent, the viscosity increases rapidly with time, so that the permeability in the ground 1 is increased. Further, it is considered that the fluidity is also lowered and the injection rate is easily lowered.
[0034]
By the way, the injection hole 2 which has finished the injection of the chemical solution 4 by the above-described method is cured until it is solidified to a predetermined strength. As shown in FIG. 23 is arranged.
The liquid level holding device 23 includes a liquid storage tank 24 in which the chemical liquid 4 is stored, and an injection pipe 25 communicating with both the liquid storage tank 24 and the injection hole 2. These are installed for the purpose of constantly applying a constant fluid pressure to the chemical solution 5 that has been applied from the injection hole 2 during curing, and when the hydraulic pressure of the chemical solution 5 that has been applied has decreased. The chemical solution 4 is newly supplied from the liquid storage tank 24 through the injection tube 25.
[0035]
Such a configuration continues to replenish the injection hole 2 with the chemical solution 4 until a fluidity of the applied chemical solution 5 disappears, and a constant fluid pressure is applied, as shown in FIG. Even if the leaked site A of the applied chemical solution 5 is generated in a part of this, an integrated improved body without a gap can be created.
The liquid level holding device 23 is not necessarily limited to the above-described configuration, and any configuration may be used as long as a constant fluid pressure can be applied to the applied chemical solution 5 at all times. May be.
[0036]
On the other hand, after the operation of injecting the chemical solution 4 into the predetermined injection hole 2 is completed, the injection operation of the chemical solution 4 is newly performed to the other injection hole 2, but the injection hole 2 in which the permeation range 1a does not overlap each other Work after selecting. This is a process in which gelation of the applied chemical solution 5 is in progress in the infiltration range 1a shortly after the injection of the chemical solution 4, so that the strength and viscosity of the applied chemical solution 5 are gradually increasing. is there. At this stage, when the chemical solution 4 is injected into the adjacent injection hole 2 where a part of the permeation range 1a overlaps, an injection pressure is applied to the applied chemical solution 5, so that the viscosity is increasing due to this injection pressure. This is because the spent chemical solution 5 may flow.
Accordingly, the other injection holes 2 for newly injecting the chemical solution 4 can be placed at any position as long as the injection operation is not continuously performed on the adjacent injection holes 2 in which the permeation ranges 1a overlap each other. An injection operation may be performed on the injection hole 2.
[0037]
(Fifth step)
The third step and the fourth step are repeated, and the chemical solution 4 is injected into the target ground 1 from all of the drilled injection holes 2.
In the present embodiment, as shown in FIG. 2, the operation of injecting the chemical solution 4 into the injection hole 2 is located every other place, such as 1 ′ → 2 ′ →... → 23 ′ → 24 ′. The injection hole 2 is carried out in order. However, the order of performing the injection operation of the chemical solution 4 is not necessarily limited to this, and as described in detail in the fourth step, the injection operation is continuously performed on the injection holes 2 where the permeation ranges 1a overlap each other. If not performed, the injection operation may be performed on the injection hole 2 in any order.
[0038]
Here, it is sufficient for the curing period of the applied chemical solution 5 that has penetrated into the infiltration range 1a to ensure at least one injection time of the chemical solution 4 into the injection hole 2 after the completion of the injection. Therefore, the injection operation into the injection hole 2 adjacent to the injection hole 2 in which the injection of the chemical solution 4 has already been completed is performed by delaying the order of the injection operations one or more times.
[0039]
In the present embodiment, one injection operation is performed at one injection hole 2, but this is not necessarily the case. For example, as shown in FIG. 2, the injection operation is located at both corners on a diagonal line. It is not affected by the deformation of the ground 1 such as the fluctuation of the groundwater level caused by injecting the chemical solution 4 into the ground 1 such as simultaneously performing the injection work on the two injection holes 2a and 2b. The injection operation may be simultaneously performed on the plurality of injection holes 2 located at a place where a sufficient separation distance is secured.
[0040]
According to the above-described configuration, since the solidification characteristics of the chemical solution 4 are evaluated in advance using a full-scale model penetration test apparatus, the plan change during the actual injection work can be changed because the difference between the solidification characteristics during the injection work is small. It becomes possible to decrease.
Further, in a state where the injection pressure is maintained within a range that does not cause splitting of the ground 1, the injection of the chemical solution 4 is continued until the injection rate is reduced to indicate that the viscosity has actually increased due to the gelation of the chemical solution 4. Therefore, the permeation performance of the chemical solution 4 can be maximized, and an effective injection operation can be performed in each of the injection holes 2.
[0041]
During the injection operation, the injection rate is monitored under a constant injection pressure or while adjusting the injection pressure to be within a certain range. Therefore, based on the measurement data of the injection time, injection rate, and injection pressure, The solidification characteristics of the chemical solution 4 at the time of the injection operation can be grasped, and various conditions relating to the injection operation including the composition of the chemical solution 4, the gel time, the injection time, the interval between the injection holes 2, etc. Accordingly, it is possible to appropriately set an efficient numerical value.
[0042]
When the injection operation of the chemical solution 4 to another injection hole 2 is newly performed after the injection operation of the chemical solution 4 to the predetermined injection hole 2 is completed, the infiltration range 1a is applied to the injection holes 2 that do not overlap each other. Since the injection operation is performed, the injection pressure is not applied to the applied chemical solution 5 penetrating into the infiltration range 1a in the process of gelation. It is possible to suppress the flow and develop sufficient strength and viscosity.
[0043]
In the injection hole 2 where the injection of the chemical liquid 4 is completed, a constant fluid pressure is always applied to the applied chemical liquid 4, so that the injected chemical liquid 5 penetrating into the infiltration range 1 a disappears until the fluidity of the applied chemical liquid 5 disappears. By continuing to replenish the chemical solution 4, it is possible to create an integrated improved body without a gap even when a leaked portion of the applied chemical solution 5 occurs in a part of the target ground 1.
[0044]
【The invention's effect】
According to the method for injecting an injection solution into the ground according to claim 1, the injection method for injecting the injection solution into the ground for injecting an injection solution suitable for improving the ground, wherein the injection solution is injected into the ground The first step of evaluating the solidification characteristics of the first and determining the composition of the injection solution suitable for the target ground, and a separation interval such that a part of the permeation range when the injection solution is injected into the ground overlap, The second step of drilling a plurality of injection holes vertically so that the infiltration range covers the target area of the ground, and the injection solution from the injection hole to the ground and the ground splitting while monitoring the injection speed The third step of injecting at a constant injection pressure in a range that does not occur, the injection is terminated when the injection speed is reduced to a predetermined value, and the infusion solution that has penetrated the ground is cured, and this and the infiltration range are From the other non-overlapping injection hole to the ground, the third work A fourth step of injecting the injection liquid in the same manner as, repeatedly third step and the fourth step, the fifth step of injecting the injection liquid to the ground than all of the injection holes.
[0045]
As a result, the solidification characteristics of the chemical solution are evaluated in advance using a full-scale model penetration test device, so there is little difference from the solidification characteristics during the injection operation, so it is possible to reduce plan changes during the actual injection operation. It becomes.
In addition, in the state where the injection pressure is maintained within a range that does not cause splitting of the ground, the injection of the chemical solution is performed until the injection rate is reduced to indicate that the viscosity has actually increased due to gelation of the chemical solution. Therefore, the penetration performance of the chemical solution 4 can be maximized, and an effective injection operation can be performed at each injection hole.
[0046]
During the injection operation, the injection rate is monitored under a constant injection pressure or while adjusting the injection pressure to be within a certain range. Therefore, based on the measurement data of the injection time, injection rate, and injection pressure, The solidification characteristics of the chemical solution during the injection work can be grasped, and various conditions relating to the injection work including the chemical composition, gel time, injection time, injection hole interval, etc. can be efficiently performed according to the injection purpose and construction conditions. It is possible to set to a numerical value.
[0047]
After completing the operation of injecting a chemical solution into a predetermined injection hole, when performing a new operation of injecting a chemical solution into another injection hole, perform the injection operation on the injection holes whose permeation ranges do not overlap each other. Therefore, since the injection pressure is not applied to the applied chemical solution that has penetrated into the penetration range in the process of gelation, the flow of the applied chemical solution that is in the process of increasing viscosity is suppressed, and sufficient strength and It becomes possible to develop the viscosity.
[0048]
According to the method for injecting an injection solution into the ground according to claim 2, in the third step, the injection solution is injected into the ground while monitoring the injection pressure, and the injection flow rate of the injection solution is increased or decreased. Thus, the constant injection pressure is maintained by keeping the absolute value of the rate of change in pressure at the time of injection within a predetermined value calculated from the change over time.
[0049]
As a result, when the injection of the chemical solution into the other injection hole is newly performed after the injection operation of the chemical solution into the predetermined injection hole is completed, the injection operation is performed on the injection holes whose permeation ranges do not overlap each other. Since the injection pressure is not applied to the applied chemical solution that has penetrated the infiltration range in the process of gelation, the flow of the applied chemical solution that is in the process of increasing viscosity is sufficiently suppressed. It becomes possible to express a sufficient strength and viscosity.
[0050]
According to the method for injecting the injection liquid into the ground according to claim 3, in the fourth step, the injection liquid that has permeated the ground is applied to the injection hole where the injection of the injection liquid has been completed while applying a constant hydraulic pressure. Curing is solidified.
[0051]
As a result, since a constant fluid pressure is always applied to the applied chemical solution in the injection hole where the injection of the chemical solution has been completed, the chemical solution is applied to the injection hole until the fluidity of the applied chemical solution penetrating the infiltration range is lost. By continuing the replenishment, it is possible to create an integrated improved body without a gap even when a leaked portion of the applied chemical liquid is generated in a part of the target ground.
[Brief description of the drawings]
FIG. 1 is a view showing an injection apparatus used in a method for injecting an injection liquid into the ground according to the present invention.
FIG. 2 is a view showing the arrangement of injection holes used in the injection method for injecting liquid into the ground according to the present invention.
FIG. 3 is a view showing an injection pressure measuring device used in the injection method for injecting liquid into the ground according to the present invention.
FIG. 4 is a graph showing the relationship between the gel time and the viscosity of the injection liquid according to the present invention.
FIG. 5 is a view showing a liquid level holding device used in the method for injecting an injection liquid into the ground according to the present invention.
[Explanation of symbols]
1 ground
2 injection hole
3 Seal grout
4 chemicals
5 Completed chemicals
6 Injection device
7 Pressurized tank
8 Compressor
9 Injection pressure control mechanism
10 Replenisher
11 Liquid storage tank
12 Supply control mechanism
13 Liquid level detector
14 Injection hose
15 Injection pressure measuring device
16 Injection pressure detector
17 Pressure transducer
18 Pressure measuring device
19 Control device
20 Injection device
21 Pump
22 Chemical injection valve
23 Liquid level holding device
24 Liquid storage tank
25 Injection tube

Claims (3)

A method of injecting an injection solution into the ground, injecting an injection solution suitable for ground improvement into the ground,
A first step of evaluating solidification characteristics when the injection solution is injected into the ground, and determining a composition of the injection solution suitable for the target ground;
A second step of vertically drilling a plurality of injection holes so that the infiltration range covers the target area of the ground with a spacing interval such that a part of the infiltration range overlaps when the injection solution is injected into the ground. When,
A third step of injecting an injection solution from the injection hole to the ground at a constant injection pressure in a range that does not cause splitting of the ground while monitoring the injection speed;
When the injection speed drops to a predetermined value, the injection is terminated, and the injection solution that has penetrated the ground is cured, and the same procedure as in the third step is performed from another injection hole where the penetration range does not overlap with the ground. A fourth step of injecting an injection solution;
A method for injecting an injection liquid into the ground, characterized by comprising a fifth step of repeating the third step and the fourth step and injecting the injection liquid into the ground from all the injection holes. In the injection method of the injection liquid to the ground according to claim 1,
In the third step, the injection solution is injected into the ground while monitoring the injection pressure, the injection flow rate of the injection solution is increased or decreased, and the rate of change in pressure at the time of injection is calculated from the change over time. A method for injecting an injection solution into the ground, wherein a constant injection pressure is maintained by keeping an absolute value within a predetermined value. In the injection method of the injection liquid to the ground according to claim 1 or 2,
A method for injecting an injection solution into the ground, comprising curing and solidifying the injection solution that has permeated the ground while maintaining a constant hydraulic pressure in an injection hole in which the injection of the injection solution has been completed in the fourth step.

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