JP2009221784A - Soil improvement construction method and its system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute soil improvement work rationally, economically, and with high efficiency without setting a manufacturing plant for solidification material slurry at each construction site by common use of the manufacturing plant at a plurality of the construction sites. <P>SOLUTION: A fixed type slurry plant 10 for manufacturing the solidification material slurry for the soil improvement work by determining formulation so as to make usable life not less than 2 hours and not more than 14 days is arranged. The solidification material slurry having an adequate usable life is carried to the construction site by a carrying device 20. The solidification material slurry is preserved in an onsite storage apparatus 30 for storing the solidification material slurry at the construction site till an arbitrary time point within the usable life, and thereafter the solidification material slurry is mixed with target soil at the construction site to carry out the soil improvement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a soil improvement work method and system. More particularly, the present invention relates to a technique for performing a highly economical and economically efficient soil improvement work using various cements and / or cement-based solidifying materials.

  There is a technique for improving soil quality using so-called “hydraulic solidifying materials” such as various cements and / or cement-based solidifying materials.

  Such soil improvement includes, for example, the formation of a continuous wall body in the ground to be improved, securing the supporting force of the target ground, and the creation of a support structure in the ground. Depending on the purpose, it is carried out by local construction to improve the soil quality of the target construction site.

  In the conventional soil improvement work, a solidifying material slurry manufacturing plant is installed at the soil improvement work site to manufacture the solidifying material slurry. For this reason, it was necessary to carry in, assemble, operate, dismantle and carry out the solidifying slurry manufacturing plant at the construction site of the soil improvement work. In some cases, it is also necessary to improve the soil below the solidifying slurry manufacturing plant, so it is necessary to interrupt the construction and move the plant before improving the soil. In addition, time for dismantling, moving and assembling for moving the plant was sometimes required.

  Conventionally, the solidifying material slurry is used immediately after production, and the remaining solidifying material slurry is disposed as industrial waste at the end of the day's work.

  In order to delay the hardening of the improved soil during the soil improvement work, depending on the actual situation of the soil improvement work, a technique for delaying the hardening of the soil improved body by adding a retarder to the solidifying material slurry is known. For example, in the construction of a composite pile body in which steel material is inserted into the soil improvement body, or in the construction of a long soil improvement pile body used for deep development work, the time required for one cycle is long, during which the solidified material It was necessary to maintain the soil improvement body obtained by mixing and stirring the slurry and the soil to be solidified in an uncured state, and for this reason, a curing delay technique was used.

  If it is necessary to delay the hardening time of the soil improvement body due to such construction conditions, the soil quality to be improved, the soil improvement work method, the construction conditions, the construction procedures, etc., the delay to the hydraulic solidification material Add an effective additive (retarding agent) to delay the hardening time of the improved soil, to ensure the workability of the soil improvement work, or to improve the portion of the improved soil that may cause discontinuities such as lapping There were times when quality was improved. In order to deal with the actual situation of such construction, there is a technique for adjusting the curing time of the soil-improved soil (for example, see Patent Document 1).

  However, this technique uses a solidified material slurry produced in a slurry plant installed in a construction site.

  In addition, as a method for adjusting the setting time of the cement, a setting retarder is added to the paste or slurry cement kneading material to delay the hydration of the cement, and a water reducing agent and a cement hardening accelerator are added thereto. There is a technique for adjusting the hardening of cement (for example, see Patent Document 2).

  This technology is related to concrete, and a polycarboxylic acid-based cement water reducing agent having a polyoxyethylene group and a cement hardening accelerator consisting of calcium aluminate silicate and gypsum are added to hold the slump, and the concrete is timely. It is a technology to cure. This technology is related to concrete and cannot be applied to soil quality improvement technology.

  In order to delay the hardening of soil-improved soil using a hydraulic solidifying material, there is also a technique for causing the soil-improved body to exhibit a desired delay effect and improve strength development (see, for example, Patent Document 3). This technology uses a curing retarder obtained by adding a retarding reinforcing aid to a conventional retarder as a curing retarder for a soil improvement material.

  In addition, there is an injecting material for ground improvement that accelerates the setting and hardening of cement, has a low temperature dependence of gel time, is easy to prepare, and is excellent in the expected and long-term strength of a solidified body (for example, patent Reference 4).

  This technique relates to a ground improvement injection material (composition) used in combination with cement for ground reinforcement, water stoppage, backfilling and the like. For example, an injection material used for filling a cracked rock layer, filling a water-permeable layer, and backfilling the back space of a tunnel lining.

This injection material has a chemical composition in terms of CaO, Na ₂ O and Al ₂ O ₃ of 54 to 65 wt% CaO, 5 to 20 wt% Na ₂ O and 21 to 40 wt% Al ₂ O ₃ 21 to 40 wt%. An injection material for ground improvement containing 10 to 200 parts by weight of gypsum and 0.01 to 10 parts by weight of a setting retarder or 100 parts by weight of Na ₂ O—Al ₂ O ₃ fired product, or 8CaO · Na ₂ O -It contains 10 to 200 parts by weight of gypsum and 0.01 to 10 parts by weight of a setting retarder for 100 parts by weight of a CaO—Na ₂ O—Al ₂ O ₃ fired product containing 50% by weight or more of 3Al ₂ O ₃ It is an injection material for ground improvement.

_{Na CaO-Na 2 O-Al} 2 O 3 based sintered product containing ₂ O is for hydration high activity to promote the setting and hardening of the cement, increase the rapid hardening significantly. Since it is necessary to adjust the gel time during use of this injecting material for ground improvement, an appropriate amount of a setting retarder is added in advance at the time of production to standardize the rapid hardening. On the other hand, it has been shown that a predetermined amount of a setting retarder is dissolved and used in kneaded water during ground improvement work, which is a conventionally known means.
Japanese Patent Laid-Open No. 10-17864 Japanese Patent No. 397331 JP 2004-43275 A Japanese Patent Application Laid-Open No. 9-1000047

  Conventionally, when soil improvement is performed using cement-based solidification material, the hydraulic solidification material is mixed with the soil to be solidified at the construction site where the soil improvement is to be performed, and the desired strength is given to the improved soil. The creation of underground structures and supporting ground has been carried out. In this case, a production plant for producing hydraulic solidifying slurry is installed at the construction site. Such a manufacturing plant needs to be installed regardless of the amount of construction work. For this reason, relatively small-scale soil improvement works could not avoid cost increases.

  In addition, soil improvement work often requires construction time intervals depending on the type of construction and the actual situation of the construction process. However, there has been no technology for adjusting the pot life of the solidifying material slurry to be appropriate. In addition, there is no known technique that ensures the uniaxial compressive strength of the improved soil that is manifested by such a solidifying material slurry when a pot life is imparted to the solidifying material slurry.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a technique for producing a solidified material slurry in which the pot life is appropriately adjusted. In addition, the present invention has heretofore stopped the installation of a hydraulic solidifying material slurry manufacturing plant at each construction site, and provided a suitable working time so as to match the actual situation of each soil quality improvement construction site. The purpose of this is to provide a technology for manufacturing soil improvement works at a large number of construction sites in a reasonably economical manner with a high efficiency.

  The present invention has been made to solve the above problems, and is characterized by taking the following technical means. That is, the present invention produces a solidified material slurry having a pot life of 2 hours to 14 days in a stationary solid material slurry production plant according to the soil quality, environment, soil quality improvement method, and construction conditions of the construction site. Then, after transporting and storing the solidifying material slurry to each soil improvement construction site, the soil is improved by mixing with the target soil within the pot life.

  Of course, when the solidified slurry manufacturing plant and the soil quality improvement construction site are close to each other, there is no need for conveyance. Moreover, according to conditions, you may provide the relay base which preserve | saves a slurry between a solidification material slurry manufacturing plant and a soil quality improvement construction site.

  In the present invention, the pot life of the solidifying material slurry refers to a period during which the solidifying material slurry can be stored without losing its properties as a soil improving material solidifying material slurry. In the present invention, the pot life is adjusted by determining the mixing amount of the slurry curing retarder and the like in accordance with the soil improvement work process and other conditions.

  In the present invention, the pot life is 2 hours to 14 days. The pot life depends on the equipment used, the mixing and mixing method, the construction process, etc., depending on the construction process plan and soil improvement method, for example, the purpose, shape, scale, size, etc. of the object to be improved. Determined. In the present invention, the degree of freedom and storage time for producing the solidified slurry can be greatly expanded.

  In the present invention, the solidified material slurry provided with a pot life of 2 hours or more is improved soil compared to a conventional solidified material slurry that does not add a retarder when used within the pot life. Consideration was made so as not to lower the uniaxial compressive strength. The blending of the solidifying material slurry having a pot life of 2 hours or more applied to the present invention was determined with this point as an important point, and this blending was confirmed by many tests.

  In the present invention, the solidified material slurry is manufactured in a stationary solidified material slurry production plant, and the solidified material slurry is transported to each soil quality improvement construction site and stored, and then mixed with the target soil. Overall rational improvement can be achieved. Therefore, by providing the stationary solidifying material slurry manufacturing plant in the region of the solidifying material slurry transportable distance, it is not necessary to install the solidifying material slurry manufacturing plant at each soil quality improvement construction site. As a result, the soil improvement work over a wide area can be performed comprehensively, rationally and economically, and it has enormous effects.

  The system of the present invention for suitably carrying out the method of the present invention comprises an on-site storage device for storing the solidified material slurry transported from the solidified material slurry production plant at the construction site of the soil improvement work. It is a soil improvement work system.

  The soil quality improvement construction system of the present invention is not equipped with a solidification slurry manufacturing plant at each construction site, and can be transferred to a wide range of construction sites that can be transported within the extended pot life. It is preferable to provide only an on-site storage device for storing the corresponding solidified material slurry.

  The on-site storage device consists only of the solidified material slurry storage tank and its accessories. Since it is not necessary to install a solidifying slurry manufacturing plant for each soil improvement work site, rationalization and economicization of the soil improvement work as a whole can be achieved.

  The on-site storage device of the present invention is a geographical condition between a stationary solidifying material slurry manufacturing plant and a soil improvement work construction site provided at a single location for a plurality of construction sites in a wide area, the scale of work on site construction, work processes, etc. Accordingly, only an appropriately sized field storage device needs to be provided at each construction site.

  In the present invention, the pot life of the solidifying material slurry is 2 hours or more and 14 days or less. As a result, the transportable distance of the solidifying material slurry can be greatly increased, and the solidifying material slurry corresponding to the construction work process can be delivered appropriately and appropriately. By providing one stationary solidifying slurry manufacturing plant in the transportable area, it is not necessary to install a solidifying slurry manufacturing plant at each work site. Each construction site is equipped with only on-site storage equipment according to the actual situation, and can use a solidified slurry that has a usable time according to the construction process. Can be performed automatically.

  If the curing delaying solidifying slurry is within the usable time, it can be used by freely selecting the storage days after kneading, and the remaining solidifying slurry at the construction site after completion of the construction is of the same composition. It can be transported to other sites and used, and the solidified material slurry can be used effectively and the amount to be discarded can be minimized.

  Depending on the type and purpose of the soil improvement work, the present invention can effectively cope with a case where the soil improvement body obtained by mixing and stirring the solidification material and the soil to be solidified needs to be maintained for a long time without curing.

  In the present invention, it is not necessary to bring a solid material slurry production plant, which is a large heavy object, to the construction site for soil improvement work, and it is not necessary to carry out assembly, operation, dismantling, and carrying out, and only the solid material slurry on-site storage device is provided. . Therefore, equipment costs, labor costs, power costs, etc. at the construction site can be reduced, and quality management and inventory management become easy.

The method of the present invention
(A) Depending on the soil quality, environment, soil improvement work method, and geographical conditions at the construction site, the solidification material slurry is produced by setting the composition so that the pot life is 2 hours or more and 14 days or less. Transport to improvement site.
(B) This solidifying material slurry can be stored in an on-site storage device or the like, and is stored up to an arbitrary point within the pot life, and then mixed with the target soil at the site to improve the soil quality.

  In the present invention, a retarder is added to the solidifying material slurry so that the pot life of the solidifying material slurry is adjusted to 2 hours or more and 14 days or less. The amount of retarder added depends on the mix of solidifying material slurry, soil quality at the soil improvement work site, soil quality improvement work method, soil improvement work process plan, transport time to the work site, construction work process, etc. Set the time and determine the amount to be added.

  Examples of retarders include commercially available chemical admixtures for concrete and dispersants for soil cement, retarders, oxycarboxylic acids or / and salts thereof, lignin sulfonates, saccharides and mixtures thereof, and sugar alcohols. An ester compound of a sugar alcohol and a higher fatty acid can be used.

  As described above, a solidified material slurry having an appropriate pot life of 2 hours or more and 14 days or less is manufactured in a stationary manufacturing plant and transported to a construction site by a vehicle equipped with a slurry tank. The construction site includes an on-site storage device for storing the conveyed solidifying material slurry, and the stored solidifying material slurry is used in accordance with the construction process. Therefore, disposal of the solidifying material slurry can be minimized.

  Findings from test studies that led to the development of the present invention will be described below.

  Table 1 shows a blending example in which the solidifying material slurry used for the soil improvement work does not harden and maintains the desired fluidity, that is, the pot life is 2 hours or more and 14 days or less.

  Table 1 will be described below.

  The amount of the slurry retarder added can be determined according to the soil improvement work method, the type of the solidifier, the water cement ratio, the pot life, and the type of the retarder.

  The addition amount (mass%) of the slurry retarder is mass% based on the solidified material, and may vary depending on the production lot of the solidified material, kneading water (water used when producing the solidified material slurry), environmental temperature, and the like.

  The soil cement column method is a method of forming a solid columnar body in the ground by stirring and mixing the ground and cement-based solidified material while injecting the solidified material while injecting into a predetermined depth using a rotary stirring device. It is. The middle is what forms the middle part of the pile. US50 or US52 is used as the solidifying material.

US50 (trade name) is a cement-based solidifying material of Ube Mitsubishi Cement Co., Ltd., which is suitable for improving soil quality of sandy soil, silt and clay. For example, the density is 3.04 g / cm ³ specific surface area of 4,280 cm ² / g. Typical chemical components are SiO ₂ : 23.8%, Al ₂ O ₃ : 8.4%, Fe ₂ O ₃ : 1.5%, CaO: 53.7%, MgO: 3.3%, SO ₃ : 6.4%.

US52 (trade name) is a cement-based solidifying material of Ube Mitsubishi Cement Co., Ltd., which is suitable for improving soil quality such as volcanic ash clay, organic soil (humus soil), and sludge with extremely high water content. For example, the density is 3.06 g / cm ³ and the specific surface area is 4,240 cm ² / g. Typical chemical components are SiO ₂ : 21.4%, Al ₂ O ₃ : 6.5%, Fe ₂ O ₃ : 1.7%, CaO: 57.7%, MgO: 2.5%, SO ₃ : 7.6%.

  Using the above solidification material for the soil cement column method, the target is W / C = 60%, and as the slurry retarder, alkaline earth metal hydroxide (67 parts by mass) and oxycarboxylate (22 (Part by mass) and lignin sulfonate (8 parts by mass) mixed powder was used.

  The display of pot life is as follows.

Pot life 1 day: pot life 2 hours to 24 hours Pot life 3 days: pot life exceeds 24 hours to 72 hours Pot life 7 days: pot life exceeds 72 hours Up to 168 hours pot life 14 days ... pot life exceeds 168 hours and up to 336 hours This display is the same in all the tables below.

As shown in Table 1, when US50 and US52 were used as solidification materials for the soil cement column method (intermediate) and the water cement ratio (W / C) was 60%, the amount of slurry retarder added to the solidification material was In US50,
When pot life is 1 day 1.50% by mass
When the pot life is 3 days 2.00% by mass
When pot life is 7 days 2.25% by mass
When pot life is 14 days 2.50% by mass
In US52,
When pot life is 1 day 1.50% by mass
When the pot life is 3 days 2.25% by mass
When pot life is 7 days 2.50% by mass
When the pot life is 14 days 2.75% by mass
Met.

  Next, the steel pipe pile method with soil cement blades is a method of building a hybrid pile by forming a columnar body (soil cement column) in the ground like the above soil cement column method and inserting a bladed steel pipe into it. It is.

  The amount of slurry retarder added to the solidified material is shown in accordance with the pot life when US50 or US52 is used as the solidifying material, the water cement ratio is 80%, and the retarder similar to the above soil cement column method is used. It was shown in 1.

  The soil cement steel pipe pile construction method forms a synthetic pile (soil cement steel pipe pile) in the ground composed of solidified bodies (soil cement columns) constructed by injecting and stirring cement slurry into the ground and steel pipes with external projections. It is a construction method. There are a simultaneous burying method in which a steel pipe is built while building a soil cement column, and a post-buying method in which a steel pipe is built after building a soil cement column. The term “middle” refers to the case where the middle part of the pile (the pile body part above the root solid part) is targeted, and the term “solid” refers to the case where the target is the rooted bulb provided on the bottom of the pile. .

  BB (Blast Furnace Cement Type B (JIS R 5211) manufactured by Sumitomo Osaka Cement Co., Ltd.) was used as the solidifying material, and the intermediate was 100% water cement and the root solid was 60% water cement. The slurry retarder used is the same as described above. The amount of slurry retarder added for each pot life is as shown in Table 1.

  The Nakahorone solid steel pipe pile method inserts and rotates the auger screw into the steel pipe pile or the steel pipe sheet pile, presses the pile into the ground while continuously excavating and discharging the soil at the tip of the pile, and then the pile tip This is a construction method in which a solidifying material slurry is sprayed onto the part at a high pressure to form a hardened tip root and an enlarged bulb. The pile tip ground is sandy ground or gravelly ground.

  N (ordinary cement (JIS R 5210) manufactured by Sumitomo Osaka Cement Co., Ltd.) or BB was used as the solidifying material, and the water cement ratio was 67%. The slurry retarder is the same as described above, and the amount of retarder added corresponding to each pot life is as shown in Table 1.

  In the wet deep layer improvement method, as with the soil cement column method, a rotary stirrer is used to excavate underground to a predetermined depth, and then the ground and cement-based solidified material are stirred and mixed while injecting the solidified material. This is a method of forming a columnar body inside. BB was used as the solidifying material, and the water cement ratio was 150%.

  As shown in Table 1, by the test, a solidification material slurry having a retarded curing property having a suitable pot life was obtained as a solidification material slurry. When this set retarding solidifying material slurry is mixed with soil to be improved at any time during the pot life, the desired hydraulic solidifying material hydration reaction starts regardless of the pot working time, Hardening of the improved soil proceeds sequentially.

  Next, Table 2 shows the results of investigating the relationship between the kneading time and the uniaxial compressive strength of the conventional solidifying material slurry in the soil improvement work method.

Table 2 is produced by the same construction method, solidifying material, water cement ratio, etc. as shown in Table 1, and using a conventional solidifying material slurry without adding a retarder, the kneading time is 0 hour, 1 hour, The change of the uniaxial compressive strength (N / mm < ² >) of the age 28 days of the soil improvement body when it is set as 1.5 hours, 2 hours, and 2.5 hours is shown.

  Immediately after the solidifying material slurry is produced, that is, with respect to the uniaxial compressive strength when the kneading time is 0, the strength decreases with the elapse of the kneading time. The strength is 98-99% at a kneading time of 1 hour with respect to the strength at a kneading time of 0 hour, and is 89-96% at a kneading time of 1.5 hours, but is 78-88% at a kneading time of 2 hours. It decreases to 65 to 79% at a kneading time of 2.5 hours. This indicates that the uniaxial compression strength is adversely affected when the kneading time is approximately 2 hours in the prior art.

  Next, examples of the present invention will be described with reference to Tables 3 to 13.

Table 3 shows the uniaxial compressive strength of the improved soil in the case of the soil cement column method (intermediate). Using US50 as the solidifying material, the unit solidifying material amount is 300 kg / m ³ , the water cement ratio (W / C) is 60%, and the pot life is 3 days and 14 days. The uniaxial compressive strength of a sample using a solidified material slurry added at 2.0% by mass and 2.5% by mass with respect to the solidified material and using Kimitsu sand as the target soil is shown at 28 days. For comparison, a conventional example with a pot life of 0 days without adding a slurry retarder was also shown.

  In addition, in the example of this soil cement column method (intermediate), in order to form the underground column that forms the middle part of the pile, in order to delay the hardening of the soil improvement body during the elapsed time of the soil improvement process, A working retarder was added in an amount of 1.0% by mass based on the solidified material. As the working retarder, a liquid was used so as to be dispersed in the slurry in a short time. Specifically, it is a mixed liquid of oxycarboxylate (solid content 27 parts by mass) and lignin sulfonate (solid content 3 parts by mass). Since the work time for such soil improvement is long, a technique using a work retarder is conventionally known for the purpose of delaying the setting time of the soil improvement soil during that time.

  The display of the storage time in Tables 3 to 13 is as follows.

Storage time 0 (immediately after): Mixing with improved soil immediately after slurry production Storage time: 2 hours ......... Mixing with improved soil after 2 hours of slurry manufacturing Storage time: 1 day ... Mixing Storage time 3 days ………… 72 hours after slurry production and mixing with improved soil Storage time 7 days ………… After 168 hours after slurry manufacturing and mixing with improved soil Storage time 14 days ……… After slurry manufacturing 336 Mixing with improved soil after the passage of time In Table 3, the pot life is 3 days, the storage time is 2 hours, the samples for 1 and 3 days, and the pot life is 14 days, and the solidified slurry is stored for 2 hours. For the 14 and 14 day samples, the uniaxial compressive strength at 28 days of age was 4.16, 4.32, 4.42, 3.89, 4.16 N / mm ² , respectively. The uniaxial compressive strength of a sample using a conventional solidified material slurry with a retention time of 0 (use immediately after production) without adding a slurry retarder was 3.81 N / mm ² .

  Based on a conventional example in which no retarder is added, a column of uniaxial compressive strength ratio is provided in the lower part of Table 3 to evaluate the value of uniaxial compressive strength of the sample of the present invention. The first line of the column of the uniaxial compressive strength ratio in Table 3 shows the ratio of the uniaxial compressive strength of the example in which the retarder was added, assuming that the uniaxial compressive strength of the sample without the retarder (conventional example) is 100%. Each value is 102 to 116%.

  The second and third lines in the column of uniaxial compressive strength ratio in Table 3 are stored for samples with a pot life of 3 days and 14 days, with a sample with a storage time of 2 hours as a reference (100%). The uniaxial compressive strength ratio of a long-time sample is displayed. In both cases, it is shown that the uniaxial compressive strength with the longer storage time is improved.

Table 4 shows the uniaxial compressive strength when US50 is used as the solidifying material for the soil cement column method (intermediate) and clay is used as the target soil. Table 4 shows that the solidification material unit solidification material amount is 300 kg / m ³ , the water cement ratio (W / C) is 60%, and the slurry retarder is added so that the usable life of the solidification material slurry is 3 days. It shows the performance of the sample.

The uniaxial compressive strength at the age of 28 days was measured for samples having a pot life of 3 days and a storage time of 2 hours, 1 day and 3 days. For reference, a uniaxial compressive strength was also shown for a sample (conventional example) using a solidifying material slurry to which no retarder was added as a comparative example. The uniaxial compressive strength of the sample to which no retarder was added (conventional example) was 3.39 N / mm ² , whereas the uniaxial compressive strength of the example in which the retarder was added exceeded this.

  For reference, a column called uniaxial compressive strength ratio was provided and evaluated in the same manner as in Table 3. Compared to the conventional example in which no retarder is added, in all the examples in which the slurry retarder is added, the uniaxial compressive strength is improved, and the storage time is 2 hours with respect to the same pot life. It can be seen that the uniaxial compressive strength is improved in the sample having a longer storage period than in the sample.

Table 5 shows that in the soil cement column method (intermediate), US52 (unit solidification material amount 300 kg / m ³ ) was used as the solidification material, the water cement ratio was 60%, and the slurry retarder was added 2.25% by mass. Using solidified slurry with a pot life of 3 days, the target soils were Tachikawa Loam (wet density 1.310 g / cm ³ , moisture content 113.9%) and Bando Loam (wet density 1.360 g / cm ³⁾ . It is the data which calculated | required the uniaxial compressive strength of the age 28 days of the sample using the water content ratio 110.3%. In the examples, 1.0% by mass of the work retarder was added to the solidified material.

  The display of the uniaxial compression strength ratio is the same as that described in Table 3. In both Tachikawa loam and Bando loam, the strength of the example in which the slurry retarder was added was improved, and the uniaxial compressive strength of the sample having a long storage time was further improved.

Table 6 shows steel pipe pile method with soil cement blade (intermediate), US50 (unit solidification material amount 300kg / m ³ ) as solidification material, water cement ratio 80%, slurry retarder addition amount 1.5 mass%, acceptable The values of uniaxial compressive strength at the age of 28 days of soil quality improvement samples using clay when the working time is 3 days, the storage time is 2 hours, 1 day, and 3 days are shown.

  The uniaxial compression strength ratio is shown in the same display as in Table 3. In the examples of Table 6, it is clear that the uniaxial compressive strength of the sample to which the slurry retarder is added is improved.

Table 7 shows steel pipe pile method with soil cement wing (intermediate), US50 (unit solidification material amount 250kg / m ³ ) is used as solidification material, and pot life is 3 days at 80% water cement ratio (W / C). And the uniaxial compressive strength in the age of 28 days of the soil quality improvement sample which used the solidification material slurry made into 7 days and used silt (Nagatsuda) as object soil.

  The display of the uniaxial compressive strength ratio is the same as in Table 3. All the uniaxial compressive strength of the Example using the solidification material slurry which added the retarder is improving.

Table 8 shows steel pipe pile construction method with soil cement blades (intermediate), US52 (unit solidification material amount 300kg / m ³ ) is used as solidification material, and the pot life at 80% water cement ratio (W / C) is 3 days. It is the data which shows the uniaxial compressive strength and strength ratio of the soil improvement material applied to Tachikawa loam and Bando loam as object soil using the solidified material slurry.

  It can be seen that when the slurry retarder is added, all the uniaxial compressive strength ratios are improved in the examples of the present invention.

Table 9 shows the soil cement steel pipe pile method (intermediate), using BB (blast furnace cement) (unit solidification material amount 250 kg / m ³ ) as the solidification material, water cement ratio (W / C) 100%, and pot life The data of the uniaxial compressive strength of the material age 28 days of the Example obtained by manufacturing the solidification material slurry of 3rd and 7th, and mixing with silt (Nagatsuda) as object soil are shown.

  The uniaxial compressive strength ratio was shown in the same manner as in Table 3. The samples using the solidified material slurry of the example of the present invention to which the slurry retarder was added all improved the uniaxial compressive strength compared to the conventional sample in which the retarder was not added. Further, even in the examples having the same pot life, the uniaxial compression strength of the longer storage days is improved.

Table 10 shows soil cement steel pipe pile method (intermediate), using BB (blast furnace cement) as solidification material (unit solidification material amount 300kg / m ³ ), water cement ratio (W / C) 100%, and adding slurry retarder A solidified material slurry having an amount of 1.0% by mass and a pot life of 3 days was produced, and the uniaxial compressive strength was examined for an example obtained by mixing with clay and a conventional example in which no retarder was added. Data is shown.

The uniaxial compressive strength of the conventional example using the solidifying material slurry to which no retarder was added was 0.44 N / mm ² . The uniaxial compressive strength ratio was shown in the same manner as in Table 3. In the examples using the solidified material slurry to which the slurry retarder was added, the uniaxial compressive strength was all improved compared to the conventional example in which the retarder was not added. Even in the embodiment with the same pot life, the longer the storage days, the better.

Table 11 shows the soil cement steel pipe pile method (root solidification), using BB (blast furnace cement) (unit solidification material amount 300kg / m ³ ) as the solidification material, water cement ratio (W / C) 60%, pot life The data of the uniaxial compressive strength of the material age 28 days of the sample obtained by manufacturing the solidification material slurry of the Example of 1st and 3rd, and mixing with gravel are shown.

  In addition, a working retarder is not used in the rooting process.

The uniaxial compressive strength of the conventional example using the solidifying material slurry to which no retarder is added is 15.8 N / mm ² . The uniaxial compressive strength ratio data is shown in the same manner as in Table 3. In the examples using the solidified material slurry to which the slurry retarder was added, the uniaxial compressive strength was all improved compared to the conventional example in which the retarder was not added. Moreover, in the Example of the same pot life, the uniaxial compressive strength with the longer preservation | save days has improved.

Table 12 shows Nakabori Negothi Steel Pipe Pile Method (Negishi), using BB (Blast Furnace Cement) (unit solidification material amount 300kg / m ³ ) as the solidification material, with a water cement ratio (W / C) of 67% The data of the uniaxial compressive strength of the material age 28 days of the sample obtained by producing the solidified material slurry for 1 day and 3 days and mixing with sand gravel are shown.

  In addition, since the solidification material slurry is jetted at a high pressure in a short time in the root-setting step, no work retarder is used.

The uniaxial compressive strength of the conventional example using the solidified material slurry to which no slurry retarder is added is 12.3 N / mm ² . The uniaxial compressive strength ratio was shown in the same manner as in Table 3. In the examples using the solidified material slurry to which the slurry retarder was added, the uniaxial compressive strength was all improved compared to the conventional example in which the retarder was not added. In the embodiment with the same pot life, the longer the storage days, the better.

Table 13 shows the wet deep layer improvement method, the target soil is sandy soil, BB (blast furnace cement) is used as the solidifying material, the unit solidifying material amount is 300 kg / m ³ , and the water cement ratio (W / C) is 150%. The example of the uniaxial compressive strength of the Example which made the slurry retarder addition amount 1.00 mass% and the pot life 3 days is shown.

  In this construction method, the work retarder was not added when the solidified slurry was used with a storage time of 2 hours, and 0.5 mass% was added when the pot life was 3 days and the storage time was 3 days.

  As shown in the column of the uniaxial compressive strength ratio, the uniaxial compressive strength ratio is improved in the examples compared to the comparative example in which the slurry retarder is not added.

  As described above, in all the examples, the uniaxial compressive strength is improved as compared with the comparative example in which no retarder is added. In the examples, the uniaxial compressive strength of the soil improvement material is improved when the storage time is extended. It became clear to do. In the conventional examples shown in Table 2, the uniaxial compressive strength decreases as the kneading time increases, and the solidified material slurry of the present invention exhibits completely different characteristics as compared to the rapid decrease after 2 hours. This is an extremely excellent feature of the present invention.

  Next, the method and system of the present invention will be described in detail with reference to FIGS.

  FIG. 3 is a flowchart showing a conventional soil improvement work system. In order to perform the soil improvement work, it was necessary to install the solidifying material slurry plant 50 at the construction site. The solidified material slurry plant 50 includes a solidified material silo 51, a water tank 52, and an additive silo 53. The solidified material slurry plant 50 includes a mixer 54 and an agitator 55 that produce a solidified material slurry by kneading the materials supplied from these. A pump 57 for feeding the slurry is provided. The produced solidifying material slurry is supplied to the construction machine via the supply path 58 to the construction machine. Depending on the construction content, a slurry tank 56 for storing the produced solidified material slurry for a short time may be installed.

  Conventionally, it has been necessary to install such a soil quality improvement construction system (slurry plant 50) at each soil quality improvement construction site.

  FIG. 1 is a flow sheet showing an embodiment of the system of the present invention. The system of the present invention is composed of a stationary slurry plant 10 provided at one place in a wide soil improvement work construction area, and an on-site storage device 30 provided at each construction site. And the conveyance means 20 which conveys the solidification material slurry from the stationary slurry plant 10 to each construction site is provided.

  The stationary slurry plant 10 has substantially the same configuration as the slurry plant 50 shown in FIG. That is, a solidifying material silo 11, a water tank 12, a slurry retarder silo 13, a mixer 14, an agitator 15, and a slurry tank 16 are provided.

  The stationary slurry plant 10 is a plant for producing various solidified material slurries having a pot life of 1 day to 14 days (2 hours to 336 hours) so as to meet the conditions of each soil improvement work site. What is necessary is just to install in the position of the appropriate location conditions which can convey the manufactured solidification material slurry to the soil quality improvement construction construction site using the conveying apparatus 20. FIG.

  The installation position of the stationary slurry plant 10 may be determined by selecting the most economical area and point for supplying the solidified slurry. For example, an equipment center or the like may be used, or it may be added to a ready-mixed concrete factory, a fluidization processing plant, or the like, and may be determined in consideration of other advantageous location conditions.

  The on-site storage device 30 includes a slurry delivery pump 36 that sends the slurry to the slurry tank 31 and the soil improvement work construction machine, and can also include a circulation pump 33 as an internal stirring means.

  The on-site storage device 30 receives the solidified material slurry manufactured by the stationary slurry plant 10 and conveyed by the conveying means 20 in the slurry tank 31 and stores it.

  The on-site storage device 30 only needs to have an appropriate capacity according to the scale, process, etc. of the soil improvement work site, and can be easily transported, installed, removed, etc. Management etc. are also easy.

  FIG. 2 is a flow sheet of a system showing an embodiment of the present invention, and shows a slurry relay base 40 installed according to various conditions. The slurry relay base 40 includes a slurry tank 41 including a stirring and circulating device, and is provided at an intermediate position between the position of the stationary slurry plant 10 and the position of the on-site storage device 30 as necessary. By providing this slurry relay base 40, it is possible to deal with a wider area of soil quality improvement work area, and it becomes possible to operate the transport device 20 most rationally according to regional conditions. Can further improve the economic efficiency.

  The soil improvement work to which the present invention is applied includes various methods using a hydraulic solidifying material slurry, such as a mechanical stirring method using a consolidation method, a high-pressure jet injection method, and a combined method of mechanical stirring and jet injection.

  The solidifying material slurry of the present invention is suitably used for such soil improvement work, semi-flexible pavement work, lift-up method in prestressed concrete pavement, tunnel, revetment and breakwater backfilling work, steel pipe column soil retaining work In addition, it can be suitably used as a curable solidifying material slurry for use in various rooting works, in prestressed concrete sheaths, and injecting into prepact concrete.

It is a flow sheet which shows the example of the system of the present invention. It is a flow sheet which shows the example of the system of the present invention. It is a flow sheet which shows a conventional device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stationary slurry plant 11,51 Solidification material silo 12,52 Water tank 13 Slurry retarder silo 14,54 Mixer 15,55 Agitator 16,56 Slurry tank 20 Conveyance device 21 Slurry tank delivery path 30 On-site storage device 31,41 Slurry tank 33 Circulation pump 34 Additional admixture tank 35 Admixture additional pump 36 Slurry delivery pump 37 Supply path 40 Slurry relay station 50 Slurry plant 53 Additive silo 57 Pump 58 Supply path

Claims (2)

  A solidifying material slurry having a pot life of 2 hours to 14 days or less is produced in a stationary solidifying material slurry manufacturing plant according to the soil quality, environment, soil improvement method and construction conditions of the construction site, and the solidifying material slurry. A soil improvement work method characterized in that, after being transported to and stored at each soil quality improvement construction site, the soil quality is improved by mixing with the target soil within the pot life.   A soil improvement work system comprising an on-site storage device for storing the solidified material slurry transported from the solidified material slurry production plant at the construction site of the soil quality improvement work.

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