JP2019031791A - Fluidized sand and its manufacturing method and ground improvement method using it - Google Patents

Abstract

To make material sand applicable even in material sand which is difficult to apply when applying a press fit type sand pile construction method and a sand filling method, by improving the properties over time as fluidized sand produced by mixing a fluidizing keeping agent.SOLUTION: In fluidized sand for ground improvement which is treated so that a fluidizing agent is added to material sand 7 together with a water content adjusting water and is transportable through piping by a pressure feeding pump, when fluidized sand has a factor of losing fluidity with time, in the material sand and the water content adjusting water, a nonionic fluidizing keeping agent is added to the material sand and/or the water content adjusting water before adding the fluidizing agent to the material sand. Also, in the method of manufacturing the fluidized sand, after mixing the fluidizing keeping agent together with the water content adjusting water into the material sand 7 or mixing the water content adjusting water in which the fluidizing keeping agent is dissolved as the water content adjusting water into the material sand 7, the fluidizing agent and a delayed plasticizing agent are mixed.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to fluidized sand in which a sanding material used for ground improvement is mixed with a fluidizing agent to be in a pumpable state, a manufacturing method thereof, and a ground improvement method using the same.

  The sand compaction pile method (SCP method) is frequently used as a countermeasure for liquefaction, and increases the density of the ground by creating a compacted sand pile in the ground. In this SCP method, since a large construction machine is used, there are many cases where it cannot be applied due to restrictions in securing a construction space. As an alternative construction method, a chemical solution injection system using a small construction machine or a method of press-fitting cement mortar may be applied, but the cost increases. From such a background, the present applicants made the material sand into a fluidized state that can be pumped by a pump as disclosed in Patent Documents 1 and 2, and reduced the cost and environmental burden by press-fitting into the ground. Has been developed and put into practical use. This construction method is called sand press-fit static compaction construction method or SAVE-SP construction method (registered trademark), and can be applied to construction in confined areas and improvement directly under existing structures by using a small construction machine.

  Patent document 1 is disclosing the basics of a press-in type sand pile construction method. In this construction method, a sand pile material fluidized material (hereinafter referred to as fluidized sand) containing a fluidizing agent and a slow-acting plasticizing agent together with water content adjustment water in the material sand is retained in the ground while maintaining the fluidized state. Press fit and plasticize in the ground. For details, as shown in FIG. 6, after the hollow tube 23 is penetrated into the ground to the design depth, the fluidized sand is press-fitted from the surface into the ground through the hollow tube 23, and the fluidized sand is put into the ground. The fluidized sand for the next step is press-fitted on this, and the improved body 25 having a predetermined length is formed by repeating this. Reference numeral 10 denotes a fluidized sand production plant, 1 a fluidized sand supply means, 2 a sand material supply means, 3 a fluidizing agent supply means, 4 a pressure feed pump, and 5 a slow-acting plasticizer supply apparatus. Patent Document 2 discloses a fluidized sand production plant. In this production plant, fluidizing agent is mixed with material sand to produce fluidized sand, and fluidized sand is mixed with sand material in the order of water, fluidizing agent, and slow-acting plasticizer. Preferably, the fluidized sand measures the weight of the sand material, and based on the weight, water, a fluidizing agent, and a slow-acting plasticizer are automatically calculated and mixed.

  FIG. 7 is a schematic view showing a change in the state of fluidized sand during construction. (A) shows fluidized sand before press-fitting. Until the fluidized sand is pressed into the ground from the hollow tube, the fluidizing agent (for example, an anionic polymer material) increases the viscosity of the pore water between the sand particles and eliminates the friction between the particles. Suppresses separation from water and maintains high fluidity. (B) shows fluidized sand during press-fitting. During the press-fitting, the fluidized sand is dehydrated and compacted into a dense state. The fluidizer remains reticulated. (C) shows the plasticized end state. In this state, the slow-acting plasticizing agent electrically neutralizes the fluidizing agent so that the network structure of the fluidizing agent cannot be maintained, and the friction between the particles is recovered.

  Moreover, in the above press-fitting type sand pile construction method, a hollow pipe having a diameter of about 100 to 200 mm is used, and an improved body having a diameter of about 500 to 700 mm is often created by injecting fluidized sand into the ground. During construction, the characteristics of the target ground are ascertained in a preliminary survey, and material sand selection and blending specifications are determined accordingly, and the produced fluidized sand can be applied through table flow tests, bleeding tests, and texture tests. Judgment is made and whether or not it is usable is determined. In addition, for the material sand of the raw material, a prescribed range that can be used in the particle size distribution is set.

Japanese Patent No. 5188894 Japanese Patent No. 5189951

  However, in actual construction, even when the material sand is within the specified range that can be used in the particle size distribution, when it is pressed into the ground as the fluidized sand produced, the pressure increases in a short time or the pressure loss increases. The amount may not reach the target value. The applicant has investigated the cause of the problem, and in the target material sand and water containing a large amount of metal ions, the material sand having a high fine particle content rate and a relatively large particle size, and the sand production area. It was found that there are effects of chemicals used in the process of washing the target sand.

Here, the following Table 1 is an example summarizing the physical property characteristics of the material sand according to the production area. The material sand from Kisogawa and Kira has a D ₅₀ (average particle size) value outside the range of use, and the material sand from Mandano and Tozaki has a high fine particle content. It has been confirmed that Houki has a high metal ion content and is rapidly plasticizing. Of course, there is a possibility that metal ions are also contained in material sand other than the method wood.

Table 1: Characteristics of material sand

  Table 2 below shows an example of examining the table flow and texture as a physical property test on the fluidized sand produced by the method of Patent Document 2 using each material sand of Table 1. The standard values in Table 2 are ranges that have been conventionally applicable to the press-fit sand pile construction method, the water content ratio is 30-40%, the table flow is 170-230, and the texture penetration stress is 6000 (Pa). It is as follows. Since these values change not only with the water content ratio but also with the elapsed time after production, it is preferable that at least the table flow and texture are satisfied with the values after 1 hour of production. From this point, the fluidized sand produced using the material sand shown in Table 1 cannot be used because the penetration stress by the texture test exceeded the standard value of 6000 (Pa) after 1 hour of production. It turns out that it is. In some material sands, the table flow value is also outside the standard value.

  The present applicant has found that, as a countermeasure against such fluidity loss, it can be improved to some extent by adding an ionic charge neutralizing additive capable of charge neutralizing cations such as metal ions (patent application). 2017-109646). However, this ionic charge neutralizing additive can provide a certain improvement effect when the cause of loss of fluidity contains a large amount of metal ions, but it can be obtained when it is caused by other factors other than metal ions. I could not. Therefore, the applicant has studied and pursued a more effective configuration as a countermeasure for loss of fluidity, and has completed the present invention.

・表２中の「×」はテーブルフローやテクスチャー（貫入応力）の値が基準値外であることを示す。
・＊法木産の含水比３０％で流動化保持剤の添加量０％のものはテクスチャー（貫入応力）が２４８，６７９（Ｐａ）以上となる。 Table 2: Test results of fluidized sand (no nonionic fluidized retention agent added) using the material sand of Table 1

“X” in Table 2 indicates that the value of the table flow or texture (penetration stress) is outside the standard value.
* The texture content (penetration stress) of 248,679 (Pa) or more for the water content ratio of 30% and the addition amount of the fluidizing retention agent is 0%.

  The purpose of the present invention is to apply a press-in sand pile construction method and a sand filling method, even if material sand is difficult to apply, as a countermeasure against loss of fluidity, including metal ions, further flow due to the particle size of the material sand, etc. It is to improve the properties over time and make it applicable as a fluidized sand produced by adding a nonionic fluidized retention agent that can effectively cope with loss of properties. Other purposes will be clarified in the description below.

  In order to achieve the above object, the invention of claim 1 is the fluidized sand for ground improvement, wherein a fluidizing agent is added to the material sand together with water for adjusting the water content ratio, and the fluidized sand is processed so as to be transportable through a pipe by a pressure pump. When the sand has a factor that causes fluidity to be lost over time in the material sand or water content adjustment water, the material sand or / and the water content adjustment water is added to the material sand before adding a fluidizing agent to the material sand. On the other hand, it is characterized by adding a nonionic fluidizing retention agent.

The above-mentioned present invention is more preferably embodied as follows. That is,
First, the fluidizing retention agent is a nonionic surfactant such as Dianol (registered trademark) (Claim 2).
Secondly, the fluidized sand has a configuration in which the penetration stress value of the fluidized sand is at least about 6,000 (Pa) at least after 1 hour of production from the texture test (Claim 3).

  On the other hand, according to a fourth aspect of the present invention, in the method for producing fluidized sand according to any one of the first to third aspects, the fluidizing retention agent is mixed into the material sand together with the water content adjustment water, or The water content adjusting water in which the fluidizing retention agent is dissolved as water content adjusting water is mixed into the material sand, and then the fluidizing agent and the slow plasticizing agent are mixed.

  Further, the invention of claim 5 is a ground improvement method such as press-fitting sand pile formation or sand filling, and the fluidized sand according to any one of claims 1 to 3 is penetrated into the ground through a pipe by a pump. It is characterized in that it is pumped to a hollow tube to be pulled out, pressed into the ground from the tip side of the hollow tube, and plasticized in the ground.

  In the first aspect of the present invention, when the fluidized sand has a factor that causes fluidity to be lost with time in the material sand or water for adjusting the water content ratio, the non-ionic fluidized retention agent can be used to characterize the fluidized sand over time. It is possible to improve and maintain normal press-fitting construction. In this case, it is important to mix the fluidization retention agent with the material sand of the raw material. If the fluidization agent is mixed with the material sand at the same time or mixed with the fluidization agent, the improvement effect cannot be expected so much. In this case, before mixing the fluidizing agent with the material sand, it is essential to eliminate or suppress the obstruction factor in advance by mixing the nonionic fluidizing retention agent with the material sand. As described above, the fluidized sand of the present invention is used as the material sand of the raw material because the material sand that was not applicable despite satisfying the specified range such as the particle size distribution can be used. The application range of material sand can be expanded, which can contribute to the expansion of application opportunities of ground improvement method using fluidized sand as well as cost reduction. Further, as inferred from the examples described later, the water content of the fluidized sand can be kept low, which is effective in reducing the input capacity into the ground and preventing the ground displacement.

  In the invention of claim 2, as a nonionic fluidizing retention agent, a nonionic surfactant such as Dianol (registered trademark) or Neugen (registered trademark) is used as a raw material sand, as is apparent from test examples described later. It becomes possible to improve the property-inhibiting factor of fluidized sand by suppressing it by mixing it with the.

  In the invention of claim 3, as the property of the fluidized sand after the improvement, the penetration stress particularly important, that is, the penetration stress of the fluidized sand after one hour from the texture test is improved to 6,000 (Pa) or less. This is a specific point. This value is significant because it has been clarified that it satisfies the standard value that is considered preferable in the current implementation.

  In the invention of claim 4, in the method for producing fluidized sand according to any one of claims 1 to 3, the ideal composition of the fluidized sand is clarified. It functions normally as described.

  In the invention of claim 5, in the improvement method such as press-fitting sand pile creation disclosed in Patent Documents 1 and 2 and sand filling disclosed in Japanese Patent No. 5478386, the press-fitting amount of fluidized sand (material sand) is Press-in construction can always be achieved as designed, since there is no shortage or large press-in loss and press-in creation becomes difficult.

It is a schematic diagram for description which showed the apparatus structure in the case of implementing the press-fit type sand pile construction method and sand filling construction method of this invention. Among the physical property test results of fluidized sand to which the present invention is applied (an example in which a nonionic fluidized retention agent is added), (a) and (b) show that the material sand is made of law wood, and the water content ratio is 30. It is a graph which shows the table flow and texture test result of 0% fluidization sand. Among the physical property test results of fluidized sand to which the present invention is applied (an example in which a nonionic fluidized retention agent is added), (a) and (b) are made from raw wood made from a method of wood, and a water content ratio of 32. It is a graph which shows the table flow of 5% fluidized sand, and a texture test result. Among the physical property test results of fluidized sand to which the present invention is applied (an example in which a nonionic fluidized retention agent is added), (a) and (b) are made from sand made from the method wood, and the moisture content is 35%. It is a graph which shows the table flow of a fluidized sand, and a texture test result. Among the physical property test results of fluidized sand to which the present invention is applied (an example in which a nonionic fluidized retention agent is added), (a) and (b) are made of raw wood and have a moisture content of 37%. It is a graph which shows the table flow of a fluidized sand, and a texture test result. It is explanatory drawing which shows the sand pile production apparatus currently disclosed by patent document 1. FIG. (A)-(c) is explanatory drawing which shows the state change of the fluidization sand at the time of construction.

  Embodiments to which the present invention is applied will be described below with reference to the drawings. In this explanation, the construction machine used in the sand press-fit static compaction method and the sand filling method, the fluidized sand production plant, the fluidized sand production method, and the sand press-fit static compaction method that is the ground improvement method are described. Then, the advantages of the present invention will be clarified by giving examples.

(Ground improvement method) The construction machine used in the ground improvement method of the present invention can be broadly divided into a crawler type that vertically penetrates or pulls out a hollow tube along a leader, and a hollow tube suspended from an auxiliary crane. There are a boring machine type that penetrates and pulls out in a state and a rotary percussion drill type that penetrates and pulls out a hollow tube at an arbitrary angle, and it is selected according to the target ground and construction depth.

  FIG. 1 shows an example of a small crawler type construction machine 1, schematically showing a fluidized sand production plant 2. The construction machine 1 includes an elevating mechanism 4 that moves the hollow tube 3 up and down, a rotating mechanism 5 that is held by the elevating mechanism 4 and rotates the hollow tube 3, and a swivel provided at the upper end 3a of the hollow tube. 15, a pump P for pumping the fluidized sand produced in the production plant 2, a pipe 16 connecting the outlet of the pump P and the swivel 15, and a pump 16 provided in the middle of the pipe 16. A pressure gauge 6 for detecting the pressure of fluidized sand is provided.

  Here, the elevating mechanism 4 is moved up and down via a rack and pinion mechanism or the like along one side of the columnar leader 12 erected so as to be movable by the base machine 10. The rotating mechanism 5 is moved up and down along the leader 12 by the elevating mechanism 4 and forwardly and reversely rotates the hollow tube 3 via a motor and a reduction gear mechanism. The base machine 10 holds the lower end side of the leader 12 in front of the cab 11, and a hydraulic device, an electric motor, etc., not shown, are mounted on the rear side of the cab 11. In the cab 11, various construction operation units and control units are arranged. The leader 12 is supported by a raised cylinder 13 or the like, and is attached to the lower side to restrain the swinging of the hollow tube 3, and the guide tool 17 is attached to the upper side to support the upper side of the pipe line 16. Etc. The upper end of the pipe line 16 is connected to the upper end 3 a of the hollow pipe 3 through the swivel 15.

  As for the pump P, a pumping structure using a hydraulic piston is selected as a pump P that does not cause particularly high suction force, confidentiality, and air suction, and can keep the change in fluidized sand property low. The pump drive is automatically controlled via a control unit arranged in the cab 11 or controlled by the operator. The pressure gauge 6 detects the pressure of the fluidized sand being pumped by the pump P, and is pressed into the ground side region from the lower end opening of the hollow tube 3, that is, the portion where the density is lowered by drawing the hollow tube and the periphery thereof. It is possible to estimate the press-fitting pressure of the fluid when And the pressure gauge 6 detects the pressure at the time of pumping of fluidized sand at the time of construction, and transmits the detection signal to the control part of the cab 11. In the control unit, the pump P stops driving when the set pressure is reached as the fluid pressure based on the detection signal.

(Fluidized sand production plant) This production plant 2 is mainly composed of a production apparatus 20 having a mixing chamber 21 and an agitator chamber 22 and the like, and sand supply means 23 such as a backhoe for feeding sand material 7 into the mixing chamber 21. , Fluidization retention agent supply means 24 for supplying nonionic fluidization retention agent, fluidization agent supply means 25 for supplying fluidization agent, water supply means 26 for supplying water for adjusting water content, plasticizing agent A plasticizing agent supply means 27 is provided for charging the material.

  When applying the sand press-fit type static compaction method, material sand selection and blending specifications are determined according to the characteristics of the target ground through a preliminary survey. In the production plant 2, the intended fluidized sand is normally produced in the mixing chamber 21 for each batch (improved body 9). Sand supplied by the sand supply means 23, ionic charge neutralizing additive supplied by the additive supply means 24, fluidizing agent supplied by the fluidizing agent supply means 25, water supply means 26 The selection criteria and action of the plasticizer supplied by the water and plasticizer supply means 27 will be clarified below.

(1) Since the target material sand is pumped in a state where the fluidity is once enhanced, it preferably has the property of having both good water retention that does not block in the piping and good drainage that dehydrates during press-fitting. For this point, refer to FIG. 6 of JP-A-2015-183466 and the related description. However, the material sand 7 here is an irregular sand that is not normal, that is, the sand contains a cation that obstructs the fluidizing agent, and the fine grain content rate causes a texture test. The sand is judged to be difficult to apply to the sand press-fit static compaction method and sand filling method. Therefore, in other cases, that is, in the case of ordinary material sand, it is needless to say that it is not necessary to mix the nonionic fluidizing retention agent of the present invention.

(2) The nonionic fluidizing retention agent improves the time-dependent properties of fluidized sand and makes it possible to maintain normal press-fitting. Specifically, it is a nonionic surfactant or similar. belongs to. Nonionic surfactants have been found to be significantly better at improving the time-dependent properties of fluidized sand than anionic and cationic surfactants. The reason for this is not well understood, but nonionic surfactants have a hydrophilic group that does not ionize when dissolved in water compared to other surfactants, and are less susceptible to water hardness and electrolytes. This is probably because of its excellent emulsification / solubilization power.

  Further, the nonionic surfactant is a surfactant that does not have a group capable of dissociating into ions, and may be any of ether type, ester type, ether ester type and the like. The chemical names and commercially available product examples are given below as preferred specific examples of the nonionic surfactant. (A) Coconut oil fatty acid diethanolamide (1: 1 type), a product example is a trade name of Dianol CDE manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (hereinafter abbreviated as “Daiichi Kogyo”). (B) Polyoxyethylene alkyl ether, product examples are trade names Neugen ET-115 and Neugen ET-135 manufactured by Daiichi Kogyo. (C) Polyoxyethylene polyoxypropylene block polymer, product examples are trade names Epan 720 and U-108 manufactured by Daiichi Kogyo. (D) Polyoxyethylene distearic acid ester, a product example is trade name Inogen DS-601 manufactured by Daiichi Kogyo. (E) Polyoxyethylene oleate, a product example is trade name Neugen ES-149D manufactured by Daiichi Kogyo. (F) Polyoxyethylene alkylamine ether, a product example is trade name Amirazine C-1802 manufactured by Daiichi Kogyo. (G) Polyoxyethylene styrenated phenyl ether, a product example is the trade name Neugen EA-137 manufactured by Daiichi Kogyo. (H) Polyoxyalkylene oleyl cetyl ether, a product example is trade name Neugen ET-129 manufactured by Daiichi Kogyo.

  The above non-ionic fluidization retention agents cannot be expected to improve much when mixed with the raw material sand at the same time as the fluidizing agent. I can't. In other words, the fluidizing agent is mixed into the raw material sand after the above-described inhibiting factors of the fluidizing agent contained in the material sand and water are eliminated or suppressed in advance by the fluidizing retention agent. Moreover, the mixing ratio of the additive with respect to the raw material sand differs depending on the target material sand and the water content ratio as inferred from the examples described later. Generally, the lower limit value of the addition amount is 0.05% or more, and the cost increases in proportion to the increase of the upper limit value of the addition amount.

(3) Water is used for adjusting the water content ratio, and it is preferable to use neutral tap water, avoiding industrial water and seawater containing components that affect the fluidizing agent and the like, particularly cations such as metal ions. . The amount of water used is usually calculated so that the water content of the fluidized sand produced is 30% to 40%. As this water content ratio increases, the input capacity also increases in proportion and it is easy to cause ground displacement.

(4) The fluidizing agent is an additive that increases the viscosity of pore water between sand particles and suppresses separation of sand and water in a saturated state to improve pumpability. Preferably, it is an anionic polymer flocculant that increases the viscosity and suppresses the settling and separation of sand particles, and may also be a nonionic polymer flocculant or a cationic polymer flocculant. These are excellent in the performance of retaining moisture inside the polymer hydrophilic groups and the polymer network, and also have high quality long-term stability. As anionic polymer flocculants, homopolymers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamide 2-methylpropane sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, and copolymers with acrylamide Is mentioned.

  The blending ratio of the fluidizing agent is 0.01 to 2.0% by weight, preferably 0.1 to 1.0% by weight, based on the material sand. If this blending ratio is too small, the material sand will not fluidize, it will be separated or clogged in the piping and cannot be pumped, and if it is too much, the fluidization effect will not change, and the cost will be increased. It will be.

(5) The amount of the slow-acting plasticizing agent used is a blending amount capable of plasticizing the fluidized sand, and is 0.001 to 2% by weight based on the material sand in the fluidized sand to be produced. %, Preferably 0.01 to 1.0% by weight. If the amount added is too small, the fluidized material will not be plasticized, and it will not be possible to produce an improved body as designed.If the amount added is too large, plasticization will occur quickly, hindering pumping and at the same time will be expensive. Become.

(Manufacturing method of fluidized sand) In the manufacturing plant 2 shown in FIG. 1, it is difficult to apply the material sand of the raw material from the texture test or the like when preparing the fluidized sand used in the sand press-fit static compaction method or the sand filling method. When it is determined that the target fluidized sand is produced in the following manner. First, mix the required amount of nonionic fluidizing retention agent uniformly with a predetermined amount of material sand corresponding to one batch amount, or the water content ratio together with the required amount of nonionic fluidization retention agent. Mix the adjustment water. Thereafter, a fluidizing sand is prepared by adding a fluidizing agent and a slow-acting plasticizing agent. For example, after preparing fluidized sand by mixing a fluidizing agent, or a fluidizing agent and water content adjustment water, or a fluidizing agent, water content ratio adjusting water and a slow-acting plasticizer with respect to the material sand. This is because, even when a nonionic fluidizing retention agent is mixed, the properties over time of the fluidized sand produced are not improved. In other words, before mixing the fluidizing agent with the material sand of the raw material, it becomes essential to eliminate or suppress the inhibiting factor of the fluidizing agent contained in the material sand by mixing a nonionic fluidizing retention agent. .

(Sand press-fit type static compaction method) This method is as follows when the feature points are exemplified in the example using the construction machine 1 of FIG. First, the operation procedure is such that the hollow tube 3 is penetrated to the design depth in the ground via the lifting mechanism 4 and then pulled out by a predetermined pitch, and the density that can be formed below the hollow tube 3 in the pulling step. The improvement body 9 having a predetermined length is formed by repeatedly performing the supply process of press-fitting fluidized sand into the low area and the surrounding area. The construction management is carried out in the control section of the cab 11 with the maximum penetration depth of the hollow tube 3 (lower end depth), the drawing length L for one pitch, the total number of pitches ((lower end depth−upper end depth) / L), Values such as the set press-fit (discharge) pressure are input to the program. The produced fluidized sand is prepared in the agitator section 22.

  At the time of construction, after the construction machine 1 is moved and positioned at the construction site, the hollow tube 3 is inserted into the ground while being rotated through the lifting mechanism 4 and the rotating mechanism 5. This penetration is determined by a signal from a depth meter (not shown) whether or not the lower end of the hollow tube 3 has reached the design depth (lower end depth). The penetration is stopped.

  Next, the control unit controls to start drawing the hollow tube 3 by one pitch (for example, 20 cm) through the lifting mechanism 4, and at the same time, the pump P is operated and the fluidized sand is pumped. It controls so that it may press-fit in the area | region formed under the hollow tube 3 with the drawing | extraction, and its circumference | surroundings. That is, the control unit determines whether or not the drawing has reached one pitch, and when it is determined that the drawing has reached one pitch, controls the lifting mechanism 4 to be stopped or in an idling state. Further, the control unit determines whether or not the press-fitting pressure of the fluidized sand discharged to the above-described region has reached a set value as the press-fitted state of the fluidized sand based on the detection signal sent from the pressure gauge 6. When it is determined that the press-fitting pressure has reached the set pressure, the pump P stops or switches an open / close valve (not shown) to a closed state. Further, the control unit determines whether or not the total number of pitches or all pitches have been drawn, and the drawing and press-fitting of fluidized sand are repeated until the total number of pitches is reached. Further, when the total number of pitches is reached, one improved body 9 is terminated. Then, after the ground improvement apparatus 1 is moved and positioned to the next construction location, the above operation is performed again.

(Example 1) In Example 1, as shown in Table 3, the raw material sand of Table 2 was used as the raw material sand, and the moisture content was 30%, 32.5%, 35%, 37 as in Table 2. % Adjusted to group. Then, the material sand having each water content ratio is further divided into three material sand samples, and the above-mentioned Dianol CDE is added to each material sand sample as a nonionic fluidization retention agent in an addition amount of 0.05% and an addition amount of 0. 0.075% and an addition amount of 0.10% (however, the material sand with a water content ratio of 37% was mixed so that the amount of addition was 0.10% of Dianol CDE5), and 10 kinds of material sand samples were prepared. Thereafter, 10 kinds of fluidized sand were prepared by mixing each material sand sample with a fluidizing agent and a slow-acting plasticizer at a predetermined ratio. Each fluidized sand was subjected to a table flow test and a texture test in the same manner as in Table 2. Table 3 lists the test results.

  In the texture test, fluidized sand (sample) is filled in a predetermined container, set as a commercially available texture test device on a tabletop physical property measuring instrument manufactured by Yamaden Co., Ltd., and then the cylinder is moved up and down at a constant speed to obtain a sample. Penetration and withdrawal 20mm from the top. The penetration stress is a value obtained by converting the maximum load ha at the time of penetration into stress. Further, the flow (table flow) test was performed in accordance with a cement physical property test method (JIS R5201-1997). These are the same in each example of Tables 2-7.

・表３中の「×」はテーブルフロー値・テクスチャー値が基準値外であることを示す。
・＊含水比３０％でイオン系流動化保持剤であるダイヤノールCDEの添加量０％のものはテクスチャー（貫入応力）が２４８，６７９（Ｐａ）以上となった。 Table 3: Test results of fluidized sand (fluidized sand of Example 1 prepared by adding a nonionic fluid retention agent) using the method wood material sand of Table 2. That is, the material sand is made of law wood, the water content ratio of the material sand is 30%, 32.5%, 35.0%, 37%, and Dianol CDE is added as a nonionic fluidization retention agent (water content ratio is 30%, Add 30.05%, 35.0% to add 0.05%, add 0.075%, add 0.10%, add 0.10% to 37% water content 10 examples in total. This comparative example is four examples of the method wood material sand of Table 2 above, the water content ratio is 30%, 32.5%, 35.0%, 37%, and no non-ionic fluidizing retention agent is added. .

“X” in Table 3 indicates that the table flow value / texture value is outside the reference value.
* The texture (penetration stress) of 248,679 (Pa) or more was obtained when the water content ratio was 30% and the addition amount of Dianol CDE as an ionic fluidization retention agent was 0%.

(Example 2) In Example 2, Neugen ET-115 was used as a nonionic fluidization retaining agent for Example 1, and the other cases were the same as Example 1. In addition, the test result of the addition amount 0% of the ionic fluidization retention agent was omitted because it was the same as in Table 3, using the method wood from Table 2.

・表４中の「×」はデーブルフロー値・テクスチャー値が基準値外であることを示す。 Table 4: Physical property test results of fluidized sand (fluidized sand of Example 2 prepared by adding a nonionic fluidized retention agent) using the method wood material sand of Table 2. That is, the material sand is made of wood, the water content ratio of the material sand is 30%, 32.5%, 35.0%, 37%, and Neugen ET-115 is added as a nonionic fluidization retention agent (water content ratio 30% When 32.5% and 35.0% are added, the addition amount is 0.05%, the addition amount is 0.075%, and the addition amount is 0.10%. When the water content is 37%, the addition amount is 0.10%. This is a total of 10 examples prepared by adding the above.

“X” in Table 4 indicates that the table flow value / texture value is outside the reference value.

(Evaluation) FIGS. 2 to 5 summarize the test results of Examples 1 and 2 in the form of graphs. In each figure, the produced fluidized sand is measured for the fluidized sand of a comparative example in which a nonionic fluidized retention agent is not added (the method of Table 2, a non-ionic fluidized retention agent added). The value is indicated by a cross. Dianol CDE is used as a nonionic fluidization retention agent. The measured value of 0.05% fluidized sand is black triangle mark, and the measured value of 0.075% fluidized sand is black square. And the measured value of fluidized sand with an addition amount of 0.10% is indicated by black circles. Neugen ET-115 is used as a non-ionic fluidization retention agent. The measured value of 0.05% fluidized sand is indicated by white triangles, and the measured value of 0.075% fluidized sand is white. Square marks and fluidized sand with an addition amount of 0.10% are indicated by white circles. From each figure, the following can be understood depending on whether or not a nonionic fluidizing retention agent is added as fluidized sand.

  First, the fluidized sand of the comparative example indicated by the x mark is a non-ionic fluidized retaining agent added, except for the table flow value and the intrusion stress value immediately after production regardless of the water content ratio. This is far from the standard value. On the other hand, since the fluidized sand of the examples other than the X mark has a nonionic fluidized retention agent added, both the table flow value and the penetration stress value are considerably physical properties compared to the comparative example. It can be seen that it has been improved. Therefore, such a method for improving the properties of fluidized sand satisfies the specified range of material sand, particle size distribution, etc., which is not applicable because it does not satisfy the specified range of particle size distribution, etc. as raw material sand. In spite of this, the material sand that could not be applied due to the above-mentioned property hindrance factors, and the applicability of those material sands were expanded, which in turn reduced costs and contributed to the expansion of application opportunities for ground improvement methods using fluidized sand. it can.

  Second, for example, as the water content ratio of the material sand increases from 30% to 35% or 37%, the probability of being within the reference value tends to increase. When the water content in FIG. 4 is 35% and the fluidized sand added to 0.05% is added by using Dianol CDE and Neugen ET-115 as nonionic fluidizing retention agents, the table flow Both values are within the standard value, but the intrusion stress value is within the standard value for the fluidized sand with Neugen ET-115 added, but the fluidized sand with the addition of Dianol CDE is It is slightly off the standard value after 1 hour of production. On the other hand, when comparing the fluidized sand added with Dianol CDE and Neugen ET-115 so that the addition amount is 0.10%, the table flow value and the penetration stress value are 1 hour after production and 3 hours after production. Both of them are within the standard values. When adopting an improvement method by adding an ionic fluidization retention agent, it is important to consider the relationship with the water content ratio. Of course, in general, the higher the water content ratio, the greater the volume of fluidized sand that should be pumped to the ground.

  Thirdly, when the degree of improvement is compared between the fluidized sand using Dianol CDE and the fluidized sand using Neugen ET-115 as a nonionic fluidized retention agent, the table flow value is as a whole. While there is not much difference, the value of the penetration stress is particularly different when the moisture content is as low as 30%, and when the moisture content is 35% or more, the difference tends to be reduced. That is, among the nonionic fluidizing and retaining agents, what is specifically used as the nonionic surfactant is preferably determined in advance according to the target material sand, water, etc., and the optimum one is selected and determined.

(Example 3) In this Example 3, as the material sand of the raw material, the product from Mandano in Table 2 was used, and the water content ratio was adjusted to 2 groups of 37.5% and 40% as in Table 2, and the nonionic system The above-mentioned Dianol CDE as a fluidization retention agent was mixed so that the addition amount was 0.10% and 0.15%, and four types of material sand samples were prepared. Thereafter, each material sand sample was mixed with a fluidizing agent and a slow-acting plasticizing agent at a predetermined ratio to prepare four types of fluidized sand. Each fluidized sand was subjected to a table flow test and a texture test in the same manner as in Table 2. Table 5 lists the test results.

・表５中の「×」はテーブルフロー値・テクスチャー値が基準値外であることを示す。 Table 5: Test results of fluidized sand (fluidized sand of Example 3 prepared by adding a nonionic fluid retention agent) using material sands from Mandano from Table 2. That is, the material sand is from Mandano, the water content ratio of the material sand is 37.5% and 40%, and four examples using Dianol CDE as a nonionic fluidization retention agent and two additive-free comparative examples. is there.

“X” in Table 5 indicates that the table flow value / texture value is outside the reference value.

(Evaluation) From the test results of Example 3, the conventional fluidized sand produced by using material sand samples made from Mandano and adjusted to a water content ratio of 37.5% and 40%, that is, nonionic Unless the fluidizing retention agent is added, the fluidized sand cannot be used because both the table flow value and the penetration stress value deviate from the standard values except immediately after production. On the other hand, fluidized sand prepared by adding a nonionic fluidizing retention agent to an addition amount of 0.10% and an addition amount of 0.15% has both a table flow value and an intrusion stress value. It falls within the standard value, and even after 3 hours of production, the water content ratio is 37.5%, and it is within the standard value except for the addition amount of 0.1%. For this reason, it can be seen from Example 3 that even the material sand that has been conventionally unusable can be used with its properties greatly improved by simply adding an appropriate amount of a nonionic fluidizing retention agent.

(Example 4) In this Example 4, Kisogawa from Table 2 was used as the material sand of the raw material, and the water content ratio was adjusted to 2 groups of 30% and 35% as in Table 2, and non-ionic fluidization was performed. Two kinds of material sand samples were prepared by mixing the above-mentioned Dianol CDE as a retaining agent so that the addition amount was 0.1% and the addition amount was 0.15%. Thereafter, two types of fluidized sand were prepared by mixing each material sand sample with a fluidizing agent and a slow-acting plasticizer at a predetermined ratio. Each fluidized sand was subjected to a table flow test and a texture test in the same manner as in Table 2. Table 6 lists the test results.

・表６中の「×」はデーブルフロー値・テクスチャー値が基準値外であることを示す。 Table 6: Test results of fluidized sand (fluidized sand of Example 4 prepared by adding a nonionic fluid retention agent) using material sand from Kisogawa in Table 2. That is, the material sand is produced in Kisogawa, 30% and 35% moisture content of the material sand, 4 examples prepared by adding Dianol CDE as a nonionic fluidization retention agent, and 2 comparative examples without addition. is there.

“X” in Table 6 indicates that the table flow value / texture value is outside the reference value.

(Evaluation) From the test results of Example 4, conventional fluidized sand prepared from a material sand sample adjusted to a moisture content of 30% and 35% using a material sand from Kisogawa, that is, nonionic fluidized retention Fluidized sand to which no agent is added cannot be used because the value of the intrusion stress deviates from the standard value except for immediately after production. On the other hand, fluidized sand prepared by adding a nonionic fluidizing retention agent to an addition amount of 0.10% and an addition amount of 0.15% has both a table flow value and an intrusion stress value. It is within the standard value, and even within 3 hours after production, it is within the standard value regardless of the water content ratio. For this reason, it can be seen that even if Example 4 is a material sand that has been conventionally unusable, simply adding a suitable amount of a non-ionic fluidizing retention agent can greatly improve its properties and make it usable.

(Example 5) In this Example 5, two sets of material sand adjusted to a water content ratio of 40% were prepared using the raw material sand of Table 2 as raw material sand, and non-ionic fluidization was performed on each material sand. Two kinds of material sand samples were prepared by mixing the above-mentioned Dianol CDE as a retaining agent so that the addition amount was 0.10% and the addition amount was 0.15%. Thereafter, two types of fluidized sand were prepared by mixing each material sand sample with a fluidizing agent and a slow-acting plasticizer at a predetermined ratio. Each fluidized sand was subjected to a table flow test and a texture test in the same manner as in Table 2. Table 7 lists the test results.

・表７中の「×」はテーブルフロー値・テクスチャー値が基準値外であることを示す。 Table 7: Test results of fluidized sand (fluidized sand of Example 5 to which a nonionic fluid retention agent was added) using the material sand produced in Tozaki in Table 2. That is, the material sand is produced in Tozaki, the water content ratio of the material sand is 40%, and two examples prepared by adding Dianol CDE as a nonionic fluidization retention agent and one additive-free comparative example.

“X” in Table 7 indicates that the table flow value / texture value is outside the reference value.

(Evaluation) From the test results of Example 5, conventional fluidized sand prepared from a material sand sample adjusted to a water content ratio of 40% using Tosaki material sand, that is, a nonionic fluidized retention agent was added. If not, fluidized sand prepared by adding a nonionic fluidizing retention agent to an addition amount of 0.10% cannot be used because both the table flow value and the penetration stress value greatly deviate from the reference value. . On the other hand, fluidized sand produced by adding a nonionic fluidizing retention agent to an addition amount of 0.15% has both the table flow value and the penetration stress value within the reference value, and is manufactured. The improvement effect is remarkable because it is within the standard value even after 3 hours. In short, it can be seen that even the fifth embodiment can be used without any problem in the past.

(Example 6) In this Example 6, two sets of material sand adjusted to a water content ratio of 30% were prepared using the Kira products shown in Table 2 as raw material material sand, and nonionic fluidization was performed on each material sand. Two kinds of material sand samples were prepared by mixing the above-mentioned Dianol CDE as a retaining agent so that the addition amount was 0.05% and 0.10%. Thereafter, each material sand sample was mixed with a fluidizing agent and a slow-acting plasticizing agent at a predetermined ratio to prepare two types of fluidized sand. Each fluidized sand was subjected to a table flow test and a texture test in the same manner as in Table 2. Table 8 lists the test results.

・表８中の「×」はテーブルフロー値・テクスチャー値が基準値外であることを示す。 Table 8: Test results of fluidized sand (fluidized sand of Example 6 to which a nonionic fluid retention agent was added) using the material sand produced in Kira in Table 2. That is, the material sand is produced in Kira, the water content ratio of the material sand is 30%, and two examples prepared by adding Dianol CDE as a nonionic fluidizing retention agent and one additive-free comparative example.

“X” in Table 8 indicates that the table flow value / texture value is outside the reference value.

(Evaluation) From the test results of Example 6, the conventional fluidized sand prepared from the material sand sample adjusted to a water content ratio of 30% using Kira material sand, that is, a nonionic fluidized retention agent was added. The fluidized sand that is not used cannot be used because the value of the penetration stress is out of the standard value after 1 hour of production. In contrast, fluidized sand produced by adding a nonionic fluidization retention agent to an addition amount of 0.05% and an addition amount of 0.10% has an intrusion stress value of 1 hour after production. After 3 hours, it was within the standard value and an improvement effect was observed. In addition, from Examples 1 to 6 above, even if the target material sand has various fluidization inhibiting factors, the water content ratio can be increased by adding a nonionic fluidization retention agent compared to no addition. Regardless, it can be seen that a significant improvement effect can be obtained.

  In addition, the above form example and Example do not restrict | limit this invention at all. The present invention only needs to include technical elements specified in the claims, and the details can be variously changed as necessary. In addition, regarding “press-fit sand pile creation (same as sand press-fit static compaction method) and ground improvement such as sand filling”, the methods described in Patent Documents 1 and 2, Patent No. 5478386, and It includes construction methods that can be easily considered from the contents.

DESCRIPTION OF SYMBOLS 1 ... Construction machine 2 ... Fluidized sand manufacturing plant 3 ... Hollow pipe 4 ... Elevating mechanism 5 ... Rotating hand mechanism 6 ...・ Pressure gauge 7 ... Material sand 8 ... Injection pipe 9 ... Improved body 15 ... Swivel 16 ... Pipe 24 ... Non Ionic fluidization retention agent supply means 25... Fluidization agent supply means 26... Adjustment water supply means 27.

Claims (5)

In fluidized sand for ground improvement that is treated so that it can be transferred through piping by a pressure pump by adding a fluidizing agent together with water for adjusting the water content ratio to the material sand,
When the fluidized sand has a factor that causes fluidity to be lost over time in the material sand and water for adjusting the water content ratio, the material sand and / or the water content ratio is adjusted before adding a fluidizing agent to the material sand. A fluidized sand characterized by adding a nonionic fluidizing retention agent to water.   The fluidized sand according to claim 1, wherein the fluidized retention agent is a nonionic surfactant.   3. The fluidized sand according to claim 1, wherein the fluidized sand has a penetration stress of at least about 6,000 (Pa) after 1 hour of production from a texture test. In the manufacturing method of the fluidized sand in any one of Claim 1 to 3,
A fluidization retention agent is mixed in the material sand together with the water content adjustment water, or a water content adjustment water in which a fluidization retention agent is dissolved as the water content adjustment water is mixed in the material sand, and then the fluidizing agent and the delayed action are mixed. A method for producing fluidized sand, comprising mixing a plasticizing agent.   In ground improvement construction methods such as press-fitting sand pile creation and sand filling, the fluidized sand according to any one of claims 1 to 3 is pumped to a hollow pipe that is penetrated into or pulled out of the ground through a pipe by a pump. A ground improvement method characterized by press-fitting into the ground from the tip side of the hollow tube and plasticizing in the ground.

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