JP2006328902A - Method of manufacturing replenishing material for ground improvement construction method and replenishing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a replenishing material manufacturing method capable of using sediment of various properties over a wide range, and easily and stably applicable to a compaction pile construction method regardless of static and dynamic. <P>SOLUTION: Construction generating earth, water and a solidifying material are inputted by predetermined blending in a generating place of the construction generating earth or a pit 1 formed in its vicinity, and this material is formed as mixed powder by agitating and mixing by an attachment 4 held by a backhoe 2. Next, the attachment held by the backhoe is replaced, and a mixture is rolled and compacted in the same pit 1 by the attachment, and is cured and solidified as it sis. Afterwards, a solidified body is ruptured in the proper size, and is carried to a ground improvement site. The solidified body is similarly crushed in the pit by the attachment 4 used for agitation and mixing, and the replenishing material having the desired grain size distribution is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a replenishment material used in a ground improvement method, particularly a compacted pile method for forming a pile in the ground and compacting the ground, and a replenishment material manufactured by the manufacturing method.

  The compacted pile method is largely divided into the ground, rotating through the casing and penetrating into the ground. Then, the supply material is put into the casing. Static compaction pile construction method for creating piles and after penetrating the ground while vibrating the casing with a vibrator, supply the material into the casing, pulling out the casing while vibrating the casing and pulling the supply material from the tip There is a dynamic compaction pile method that discharges and creates piles in the ground. In such a compacted pile method, good quality sand and gravel are generally used as the replenishing material in consideration of discharge from the casing, pile strength after creation, etc. It has become difficult to obtain and its cost has been increasing.

For this reason, for example, Patent Document 1 proposes to use a mixed granular material obtained by stirring and mixing excavated sediment and cement-based solidified material as an alternative to the supplement material, and Patent Document 2 discloses a supplement material. Has been proposed to be discharged into the ground through the bag body.
JP-A-10-183600 JP 2003-239269 A

  However, according to the measures described in Patent Document 1, since the mixed powder and solids are solidified by absorbing moisture in the ground, the pile strength after formation is ensured, but the silt content contained in the excavated earth and sand Fine sand and fine cement particles are likely to adhere to the inner wall of the casing. In particular, in the static compaction pile method, the adhesion and accumulation of these particles on the inner wall of the casing becomes remarkable, and the application thereof becomes virtually impossible. On the other hand, according to the countermeasure described in Patent Document 2, since earth and sand are put into the bag body, there is no restriction on the properties of the earth and sand, but troublesome work such as storing the bag body in the casing in advance is required. In addition, there is a risk of breakage of the bag, which is problematic in terms of workability and stability.

  The present invention has been made in view of the above-mentioned conventional problems, and the problem is that a wide variety of soils having various properties can be used, and compacted piles regardless of whether they are static or dynamic. An object of the present invention is to provide a method for producing a supplement that can be applied to a construction method simply and stably, and also to provide a supplement obtained by the production method.

  In order to solve the above-mentioned problems, a method for producing a replenishment material for ground improvement according to the present invention comprises a stirring and mixing step of stirring and mixing earth and sand, water and a cement-based solidifying material to obtain a mixture, and compacting the mixture. A compacting step for directly solidifying the solidified product, and a crushing step for crushing the solidified product to have a predetermined particle size distribution.

  In the replenisher manufacturing method performed in this way, the solidified body is once crushed and then crushed, so that a desired particle size distribution can be obtained regardless of the properties of the earth and sand as the raw material. Therefore, the obtained replenishment material, as well as conventional general-purpose sand and gravel, can be applied to the static compaction pile method as well as the dynamic compaction pile method, and the discharge from the casing is good. It will also contribute to securing pile strength after construction.

  In the present manufacturing method, the agitation mixing, compaction and crushing operations may be performed by an attachment provided on the backhoe. In this case, each operation can be performed easily and at low cost without relying on a special machine.

  In this manufacturing method, the above-described stirring and mixing and compacting operations are performed at or near the place where the earth and sand are generated, and the solidified body after the compacting is transported to the ground improvement site and is crushed at the ground improvement site. It may be. In this way, the solidified material is generated at or around the place where the sediment is generated, and the solidified material is transported to the ground improvement site, so that when the dry soil is used, the chance of scattering of the sediment is remarkably reduced, and the surrounding environment is improved. Useful. Moreover, since the volume of the mixture is reduced by compaction, the cost required for transportation from the place of occurrence to the ground improvement site is reduced, and the space required for the accumulation storage is also reduced.

  The ground improvement method supplementary material according to the present invention is a supplementary material manufactured by the above-described manufacturing method, characterized in that earth and sand are construction generated soil. According to such a replenishment material, it is possible to effectively use construction-generated soil as waste, which is advantageous in terms of cost and greatly contributes to reduction of the final disposal amount of waste.

  According to the method for manufacturing a supplement for ground improvement method according to the present invention, not only can soil of various properties be used extensively, but also easily and stably in a compacting pile method regardless of whether it is static or dynamic. Applicable and the resulting supplements are extremely useful as a substitute for sand and gravel.

  In addition, according to the replenishment material according to the present invention, it is possible to effectively use construction generated soil that becomes waste, which is not only advantageous in terms of cost, but also contributes to reduction of the final disposal amount of waste, Its utility value is great.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a manufacturing process of a replenishment material as one embodiment of the present invention. In the present embodiment, the supply material is manufactured using the construction generated soil as a raw material. The process A for accumulating the construction generated soil, the process B for adjusting the water content ratio of the construction generated soil, and the construction generated soil with the adjusted water content ratio. Mixing water and solidifying material, stirring and mixing to obtain a mixture C, step D for compacting the mixture, step E for curing for a predetermined period in a compacted state to form a solidified body, crushing the solidified body The process F includes a process F for obtaining a replenishment material having a predetermined particle size distribution and the process G for accumulating the replenishment material obtained in this manner.

  In this embodiment, the kind of construction generated soil is arbitrary, and it is possible to select ground excavated soil, generated residual soil in shield work, discharged soil in dredging work, dredged soil, and the like. These construction-generated soils (earth and sand) are collected here or in the vicinity of them (process A), and when selecting soil containing a large amount of water, such as residual soil generated from shield construction or dredged soil, the sun is left as it is. To obtain a predetermined water content ratio (step B). The blending amount of water and solidifying material with respect to the earth and sand is determined in consideration of the strength of the solidified body obtained in the subsequent step E. This strength affects the difficulty of crushing in the subsequent process F. If the strength of the solidified body is too high, the subsequent crushing becomes difficult and the productivity deteriorates. In this embodiment, the blending amount of water and solidifying material is determined so that a solidified body exhibiting a strength of about 5 to 10 MPa can be obtained by curing for one week (one week of material age). In addition, the kind of solidification material mix | blended with earth and sand is arbitrary, As well as normal Portland cement, early strong Portland cement, blast furnace cement, etc. can be used.

  In the present embodiment, the operations (processing) of the stirring and mixing in the step C, the compaction in the step D, and the curing in the step E are performed at the location where the construction generated soil is accumulated (where the construction generated soil is generated or in the vicinity thereof). On the other hand, the pulverization of the process F is performed at the ground improvement site. Further, as shown in FIG. 2 or FIG. 4, the agitation mixing, compaction, and crushing operations are performed by an attachment 4 or a later-described attachment 4 provided at the tip of the arm 3 of the backhoe 2 in the pit 1 formed on the ground surface. 5 is performed. As an example, the size of the pit 1 is 5 to 10 m square and is set to a depth of 30 to 50 cm.

  FIG. 2 shows the state of implementation of stirring and mixing (step C). In the pit 1, the above earth and sand, water (no water is required when the water content ratio is adjusted), and a solidified material are predetermined. It is thrown to become the ratio of As shown in FIG. 3, the attachment 4 to be provided to the backhoe 2 is formed by arranging motor-driven cutting screws 4b on the bottom of the bucket portion 4a in multiple axes. Commercially available. When stirring and mixing, the arm 3 of the backhoe 2 is operated to scoop up the earth and sand (including water and solidified material) in the pit 1 into the bucket portion 4a of the attachment 4, and the cutting screw 4b is rotated in this state. Then, the earth and sand in the bucket portion 4b pass through the gap between the cutting screws 4b, and during this time, the earth and sand, water, and the solidifying material are agitated and mixed. The pit 1 is filled with a mixture of earth and sand, water, and a solidifying material by repeating the above-described treatment with the backhoe 2.

  FIG. 4 shows the implementation status of compaction (process D). The attachment 5 used for compaction is configured as a vibration compactor having a vibration generator 5b at the base end of the bucket part 5a, and the back surface of the bucket part 5a serves as a compaction surface. At the time of compaction, the arm 3 of the backhoe 2 is operated so that the back surface of the bucket 5a is brought into contact with the mixture M in the pit 1 after the stirring and mixing with a predetermined pressing force, and the exciter 5b is activated while being attached. 5 is moved in the pit 1. Then, the mixture M in the pit 1 is compacted by the movement of the attachment 5.

  In this embodiment, after finishing the above-mentioned compaction (process D), it hardens | cures for a predetermined period in the pit 1 as it is, and is set as a solidified body (process E). Since the solidified body solidified in this way has an expression strength of about 5 to 10 MPa for one week as described above, it easily breaks when an impact is applied from the outside. Here, the attachment 5 used for the compaction is used as it is, the solidified body is broken to an appropriate size using the claw portion 5c at the tip of the bucket, and this is transported to the ground improvement site, and a predetermined place Accumulate in

  A pit similar to the pit 1 is formed at the ground improvement site, and when the crushing (step F) is performed, a predetermined amount of solidified fragments are introduced into the pit from the accumulation location. Then, the same attachment as the attachment 4 used for the agitation and mixing is attached to the backhoe in the manner shown in FIG. 2, and the solidified fragments are scooped up from the pit to the bucket portion 4a, and the cutting screw 4b is rotated in this state. Let Then, the fragments of the solidified body in the bucket portion 4b pass through the gaps of the cutting screw 4b while being crushed, and a replenishment material having a predetermined particle size distribution can be obtained by repeating this process.

  Since the replenishment material thus obtained has a desired particle size distribution, it will adhere to and accumulate on the inner wall of the casing, not only for the dynamic compaction pile method but also for the static compaction pile method. No, it will be sufficient for securing pile strength after construction. In addition, since it is possible to recycle construction generated soil that becomes waste, even if processing costs such as agitation mixing, compaction, and crushing are taken into consideration, the amount of replenishment material is less than when expensive sand or gravel is used. Cost is reduced. Moreover, since the final disposal amount is reduced by recycling the waste, it greatly contributes to the reduction of the environmental load. Especially in this embodiment, since each operation | work of stirring mixing, compaction, and crushing is performed by the attachment which gave the backhoe, each operation | work can be performed simply and at low cost. In addition, since the solidified material is produced at or near the site where the construction generated soil is generated and transported to the ground improvement site, even if the construction generated soil is dry soil, it is prevented from being scattered and helps to improve the surrounding environment. Further, since the volume of the earth and sand mixture is reduced by compaction, the cost required for transportation from the generation site to the ground improvement site is reduced, and the space required for the accumulation and storage is also reduced.

After using the discharged soil (sediment) in the ground improvement work (static compaction pile method) in Taniyama, Kagoshima Prefecture as a raw material and adjusting its water content ratio, as shown in Table 1, soil (S) and water (W ) And cement (C) are stirred and mixed so as to have various blending ratios, and the resulting mixture is filled into a mold having a diameter of 10 cm and a height of 20 cm, and then solidified and cured as it is to obtain a solidified body. Was subjected to a uniaxial compression test. Next, the solidified body is crushed (attached once) by the attachment 4 as a stirring and mixing and crushing machine shown in FIG. 3 to obtain a replenishment material, and the particle size distribution of the obtained replenishment material is measured. did. The discharged soil had a density of 2.3 t / m ³ , a water absorption rate of 5.36%, and a water content ratio of 22.9%.

  Table 2 shows the results of the uniaxial compression test, and FIGS. 5 and 6 show the results of the uniaxial compression test arranged in terms of cement water ratio (C / W) and unit cement amount (C), respectively. . From these results, the compressive strength increases linearly as the cement water ratio (C / W) increases and the unit cement amount (C) increases, but the cement water ratio (C / W) is about 0.75, When the unit cement amount (C) is about 250 kg, the compressive strength is within 10 MPa or less, and if it is this level, subsequent crushing will not be difficult.

FIG. 7 shows the measurement result of the particle size distribution. In the figure, the solid line represents the particle size distribution of the replenishment material obtained in this example, and the broken line represents the particle size distribution of the earth and sand (discharged soil) used for the production of the replenishment material. In general, as the supply material used in the static compaction pile method, is 10% pass diameter D ₁₀ of 0.1mm or more, it is desirable that the uniformity coefficient Uc (D ₆₀ / D ₁₀₎ of 5 or more However, although this replenishment material has a little more gravel, it is clear that the above conditions are sufficiently satisfied and can be stably used in the static compaction pile method. In addition, it can be said that the earth and sand as a raw material has many fine particles, and if it is used as it is, a problem remains in the discharge property from the casing.

It is a flowchart which shows the manufacturing process of the supplementary material as one Embodiment of this invention. It is a schematic diagram which shows the implementation condition of the stirring mixing process in this manufacturing process. It is a perspective view which shows the structure of the attachment of a backhoe used for the stirring mixing process shown in FIG. It is a schematic diagram which shows the implementation condition of the compaction process in this manufacturing process. It is a graph which arranges and shows the result of the compression test after solidification in the example of the present invention by the cement water ratio (C / W). It is a graph which arrange | positions and shows the result of the compression test after the solidification in the Example of this invention by unit cement amount (C). It is a graph which shows the particle size distribution of the supplementary material obtained in the Example of this invention in contrast with that of discharge soil.

Explanation of symbols

1 pit 2 backhoe 4 attachment (mixing and crushing machine)
4b Cutting screw 5 Attachment (for rolling)
5b vibrator

Claims (4)

  Agitation and mixing step of stirring and mixing earth and sand, water and solidifying material to obtain a mixture, compacting step of compacting the mixture into a solidified body, and crushing the solidified body to have a predetermined particle size distribution A method for producing a replenishment material for ground improvement method, comprising a crushing step.   The method for producing a replenishment material for ground improvement method according to claim 1, wherein the operations of stirring, mixing, compacting, and crushing are performed by an attachment provided on a backhoe.   The mixing and compacting operations are carried out at or near the place where the earth and sand are generated, the solidified body after the compacting is transported to the ground improvement site, and crushing is performed at the ground improvement site. A method for producing a supplement for ground improvement according to 1 or 2. A supply material manufactured by the manufacturing method according to any one of claims 1 to 3, wherein construction-generated soil is used as earth and sand.

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