JP2016017341A - Liquefaction countermeasure construction method for existing underground pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquefaction countermeasure construction method for an existing underground pipe which can simply and at a low cost suppress the uplift and others due to liquefaction of an existing underground pipe such as a gas pipe laid in a foundation having a non-liquefaction layer such as a gravel layer in a surface layer part or a foundation having the surface layer part coated with asphalt pavement.SOLUTION: In a foundation having risk of liquefaction which has an asphalt pavement 11 in a surface layer part, in the upper part of the foundation where an underground pipe 1 is laid, a plurality of consolidated bodies 12 are integrally formed with the underground pipe 1 and at a spacing in the tube axis direction of the underground pipe 1 so as to apply a weight to the underground pipe 1. A support body 13 is formed so as to support the underground pipe 1 downward from the top between the consolidated body 12 and the asphalt pavement 11. The weight and interval of each consolidated body 12 and the number and interval of the support body 13 are set so as to suppress the rotation of the consolidated body and the uplift and rotation of the underground pipe 1 due to liquefaction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquefaction countermeasure method for an existing buried pipe by chemical injection, and is a ground that may be liquefied, and in particular, a ground having a non-liquefiable layer such as a gravel layer or a dense sand layer in a surface layer portion, or a surface layer Rotation of buried pipes that may occur along with levitation due to liquefaction of existing buried pipes such as gas pipes, water pipes, sewage pipes, etc. laid in the ground covered with asphalt pavement or concrete pavement, etc. Can be controlled easily and economically.

  In recent years, the floating due to liquefaction of existing buried pipes such as gas pipes, water pipes, and sewage pipes laid in the ground during an earthquake has become a major problem, and the present invention is about the floating of such existing buried pipes. Can be controlled easily and economically by the chemical injection method.

  In general, the liquefaction countermeasure method by injecting chemical solution is a sand gel (injection material) that lowers the water permeability of the ground and gives adhesive strength by injecting a solidifying chemical solution into a certain range of the ground through an injection tube. This is a method to stop the flow of water in the ground or increase the strength of the ground by forming a solidified body that has penetrated into the soil and hardened, and the injection material does not contain deleterious substances or fluorine compounds. A water glass chemical (the main ingredient is sodium silicate) is used.

  However, since the chemical injection method is highly reliable as a countermeasure against liquefaction but is expensive, it is widely used to improve the seismic resistance of foundations that support important buildings. Has not been used so far.

  This is because, although there are a large number of existing buried pipes that need countermeasures against liquefaction, the existing buried pipes themselves are considered to have no merit of using expensive chemical solutions because they are inexpensive.

  However, the chemical injection method has sufficient merit compared to other liquefaction countermeasure methods, especially in urban areas and urban areas from the viewpoint that construction is possible in a relatively small work space and noise problems are small. It is clear. In addition, an environment-friendly injection material that can be expected to be permanent, such as non-polluting colloidal silica grout, has been developed.

  For this reason, the biggest concerns regarding whether or not to use the chemical solution injection method as a countermeasure for liquefaction of existing buried pipes are cost and workability. If these two points can be solved, the usefulness can be said to be immeasurable.

  By the way, as a countermeasure against liquefaction of the existing buried pipe by the ground injection so far, for example, Patent Document 1 and Patent Document 2 are disclosed. In Patent Document 1, all the extension of the surrounding ground of the existing buried pipe is performed by the high pressure injection method. A method of consolidating with is disclosed.

  Further, Patent Document 2 discloses a method for preparing for liquefaction by forming a solidified support at a joint portion (connecting portion) of an embedded pipe that is easily broken particularly during liquefaction.

  In order to solve the above problems, the present applicant has already filed Japanese Patent Application No. 2013-135182, and has improved workability and invented the Japanese patent application 2014 for solidifying by osmotically flowing the consolidated material from the upper part of the buried pipe. -089735 has been filed. In particular, the present invention is a further development of a method of forming a consolidated body near the upper portion of the buried pipe and preventing the buried pipe from being lifted by its weight.

JP 7-300851 A Japanese patent No.5156989 Patent No.4672693 Patent No. 3724644

State-of-the-art chemical solution injection method Riko Books Shunsuke Shimada October 31, 1995 (P.139 Figure 3.5, P151 Photo 3.7 (a), P152 Photo 3.8, Photo 3.9)

  However, since the method disclosed in Patent Document 1 injects the injection material over the entire length around the existing buried pipe at a high pressure, it requires a large-capacity injection material, increases the cost, and requires a considerable number of days until the construction is completed. There is a problem such as requiring. Furthermore, the existing buried pipe may be damaged by the high-pressure injection of the injection material.

  On the other hand, in the method disclosed in Patent Document 2, even if the joint portion (connecting portion) of the buried pipe, which is considered to be particularly easy to break during liquefaction, is supported by a solidified support, the buoyancy during liquefaction is high. If it is large, the buried pipe may be lifted and damaged, and since the existing buried pipe buried in the ground cannot be seen, the existing buried pipe buried several kilometers to several tens of kilometers in the ground. It is not easy to inject a chemical solution into the joint part of the pinpoint.

  In addition, even if it is said that a liquid support is formed by injecting a chemical solution into a joint portion of an existing buried pipe to form a consolidated support body, depending on the shape and position of the consolidated support body, the existing embedded pipe may be attached as the surrounding ground liquefies. When it floats, a rotational force is applied to the existing buried pipe by an eccentric load, which may cause the joint portion of the existing buried pipe to come off or the existing buried pipe to be damaged.

  In general, buried pipes such as gas pipes and water and sewage pipes are laid in the ground for several to several tens of kilometers. In residential areas such as condominiums where detached houses are densely packed, Often laid to sew inside.

  For this reason, applying the conventional chemical solution injection method as it is to the liquefaction countermeasures of the buried pipe may lead to a large amount of injection of the injection material. In addition, there is a problem of space for installing an injection facility such as an injection plant, and it is necessary to inject while moving the injection plant over a long distance section. It was.

  Furthermore, the conventional liquefaction countermeasure method for existing buried pipes by injection of chemical solution has supported the bearing capacity by simply consolidating a fixed area where the buried pipe is laid or an area that is particularly susceptible to destruction by liquefaction with an injection material. This was done based on the idea of increasing the flow rate, making it easier for the injection material to be injected excessively, making it extremely difficult to economically implement countermeasures for liquefaction of existing buried pipes with a minimum injection amount. .

  In addition, even if the ground where buried pipes such as gas pipes and water and sewage pipes are liquefied, the entire ground where the buried pipes are liquefied and only the backfill part of the buried pipes are liquefied. There are various forms of liquefied ground, especially when the surrounding ground is not liquefied.

  The optimum injection method for such ground can be approached from various directions. For example, the amount of injection at one location should be set at a cost while preventing the underground pipe from rising. Can be reduced the most, or how far the best is to form a consolidated body with respect to the buried pipe, or what shape to form the consolidated body is stable during an earthquake Therefore, there has been little study on what kind of method should be used for that purpose.

  In addition, a method of forming a consolidated body around the upper surface of the buried pipe and increasing the weight of the buried pipe to resist buoyancy during an earthquake seems to be simple in terms of workability. As a result of the seismic force, the solid body is displaced and rotated in the muddy water, so that the shape integrated with the buried pipe cannot be maintained, and as a result, the buried pipe rises or rotates to prevent liquefaction. It becomes impossible (Fig. 5 (a), (b)).

  The present invention has been made to solve the above problems, solves the problems of construction cost and workability so far, and embeds existing burying due to liquefaction by the minimum amount of chemical injection and labor It is an object of the present invention to provide a liquefaction countermeasure method for an existing buried pipe that can most effectively suppress the floating of the pipe.

  The present invention has a non-liquefiable layer on the ground surface layer portion, a non-liquefiable layer such as an unsaturated ground above the ground water surface, or a lining layer such as asphalt pavement, among the ground that may be liquefied. It is an invention of a liquefaction countermeasure method for existing buried pipes laid in the ground, and by forming a plurality of consolidated bodies around the buried pipe integrally with the buried pipe and at intervals in the tube axis direction of the buried pipe In addition to giving weight to the buried pipe, the solidified body is fixed to the non-liquefied layer or the lining layer located on the upper part of the buried pipe to suppress the rotation or displacement of the solidified body accompanying the liquefaction. Is to suppress the floating of the buried pipe.

  The present invention is a ground that may be liquefied, and in particular, a non-liquefied layer such as a gravel layer or a dense sand layer or a non-liquefied layer such as an unsaturated ground above the groundwater surface is formed on the surface layer of the ground. It is suitable for liquefaction measures of buried pipes laid in a relatively shallow position of the ground that has the ground or the surface layer covered with asphalt pavement or concrete pavement (Fig. 3 (a), Fig. 10 (a) ~ (See (d)).

  The consolidated body has a plurality of injection pipes installed in the ground where the buried pipes are laid, spaced apart in the tube axis direction of the buried pipes, and the injection material is injected into the surrounding ground of the buried pipes through the injection pipes. It can be easily formed by infiltrating the injection material around the buried pipe, solidifying the ground around the buried pipe, and fixing it to the non-liquefied layer or lining layer of the ground surface layer part ( (See FIG. 3 (a) and FIGS. 10 (a) to (d)).

  The injected material is allowed to flow through the ground and flow down into the ground around the buried pipe (see Figs. 13 and 14) to prevent damage and displacement of the buried pipe in conventional high-pressure injection. can do.

  In addition, the solidified body can be formed in any shape and size at one or a plurality of locations around the buried tube, depending on the position and depth where the injection tube is installed. By installing a plurality of injection tubes at the injection point, the injection time can be shortened and a solidified body can be formed in a short time (see FIG. 10 (d)).

  In addition, when the buried pipe is embedded at a position considerably deeper than the non-liquefied layer or the lining layer on the ground surface layer portion, the buried pipe is placed below the consolidated body and the non-liquefied layer or the lining layer. In addition to forming the support so as to support toward the surface, fixing the support to the non-liquefiable layer or the lining layer can suppress the floating of the buried pipe.

  In this case, by setting the number and interval of the supports and the weight and interval of the consolidated body so as to suppress the rotation or displacement of the consolidated body accompanying liquefaction, the floating of the buried pipe can be appropriately suppressed. Can do.

  In addition, the support body is embedded between the solidified body and the non-liquefied layer or the lining layer of the surface layer portion of the injection pipe inserted to form a solidified body around the buried pipe (Fig. 1, 2), or by embedding a steel material such as a shape steel or a reinforcing bar in the ground after the injection pipe is pulled out.

  In addition, the support can be formed by continuously solidifying the ground in a certain area above the buried pipe in a column shape from the consolidated body to the non-liquefied layer or the covering layer of the surface layer portion. The strength of the support can be increased by inserting an injection tube or a rod-shaped member such as steel or reinforcing bar into the consolidated body (see FIGS. 12 (a) to 12 (c)). In addition, when the buried pipe is laid in a relatively shallow liquefied ground near the non-liquefied layer or the lining layer of the surface layer, the solidified body formed around the existing buried pipe is non-liquid. It may be formed by injecting an injection material so as to be fixed to the conversion layer or the lining layer (see FIGS. 10 (a) to 10 (d)). In addition, by injecting the solidified body so as to be fixed to the non-liquefied layer or the lining layer located above the buried pipe in the surface layer portion, the solidified body due to seismic motion or buoyancy during liquefaction in mud water It is possible to prevent the buried pipe from being lifted by suppressing the rotation and deformation.

  In fixing, a solidified body of a predetermined size is formed, and the injection point is placed so that the upper part of the solidified body reaches the non-liquefied layer located at the upper part of the buried pipe. When the buried pipe is at a deep position in the liquefied layer, the consolidated column having a smaller cross section than the consolidated body is positioned in the non-liquefied layer while being pulled up to the non-liquefied layer and integrated.

  Since liquefaction occurs below the groundwater surface, the ground above the groundwater surface can be regarded as a non-liquefied layer. In the above, the solidified column in the non-liquefied layer is regarded as a support that maintains the shape of the solidified body even in liquefaction by integrating the solidified body in the liquefied layer and the non-liquefied layer or lining layer. be able to. In this way, an economically stable liquefaction countermeasure can be achieved.

  At this time, the weight and interval of each consolidated body and the quantity and interval of the support can be set so as to suppress the floating and rotation of the buried pipe accompanying liquefaction (FIG. 3).

  The present inventor, when there is a non-liquefied layer on the ground surface, by fixing the consolidated portion to the non-liquefied layer, the shape of the consolidated body at the time of an earthquake even if most of the consolidated body is in the liquefied layer Was found, and the present invention was completed.

  Although it is already known that liquefaction can be prevented by forming a consolidated body entirely along the buried pipe, this is extremely uneconomical and poor in workability. On the other hand, the present invention has found that liquefaction can be prevented economically by forming a relatively small consolidated body integrally with the buried pipe at an interval. When the liquefaction is liquefied, seismic motion acts in the muddy water, so if you want to form a consolidated body on the upper part of the buried pipe and prevent the liquefaction from lifting due to its weight, there is enough weight. However, it becomes difficult to stabilize the buried pipe by causing rotation and displacement.

  The present invention solves such a problem, and forms one or a plurality of the necessary minimum amount of solidified body integral with the buried pipe around the buried pipe to give weight to the buried pipe. One or more supports are formed between the consolidated body and a non-liquefiable layer such as a gravel layer or a dense sand layer on the ground surface layer, or a lining layer such as asphalt pavement or concrete pavement, and the buried pipe is lowered below By supporting toward the surface, rotation and deformation of the solidified body due to liquefaction during an earthquake are prevented, and floating and rotation of the buried pipe are suppressed.

  In particular, by forming a support so that the buried pipe is supported from the top to the bottom between the consolidated body and the non-liquefied layer or lining layer of the ground surface layer, the floating of the buried pipe simply due to liquefaction In addition to preventing the rotation of the solidified body due to liquefaction, it is possible to prevent the rotation and deformation of the solidified body from occurring in the muddy water. 1 (a), (b) to FIG. 4).

  For the purpose of suppressing the floating of the buried pipe due to liquefaction, forming a consolidated body around the buried pipe and giving weight to the buried pipe will float depending on the position and shape of the consolidated body. At the same time, the buried pipe is rotated (see Figs. 5 (a) and 5 (b)), which may damage the buried pipe. Injected so as to be fixed on the lining layer, or the embedded body is integrated with the upper surface of the burying pipe. By forming the support body that supports toward the surface, the buried pipe can be reliably prevented from rotating (see FIGS. 1, 2, and 3).

  For example, by inserting an injection pipe into the upper ground of the buried pipe in the ground where there is a possibility of liquefaction, and then injecting the injected material into the ground through the injection pipe, the solidified body is fixed to the ground. It can be formed by solidifying the range.

  The injection tube is buried in the ground without being recovered, and the upper end portion of the injection tube is fixed to the non-liquefied layer or the lining layer of the ground surface layer portion with a solidifying material such as cement to form a support ( Fig. 1 (a) (b), Fig. 2 and 4).

  In addition, when the ground where the buried pipe is laid is particularly high in the ground where liquefaction is likely to occur, a plurality of injection pipes are inserted at intervals in the direction perpendicular to the pipe axis of the buried pipe. By injecting material into the ground through the injection pipe, the ground at the top of the buried pipe is solidified in a certain area in the direction perpendicular to the pipe axis of the buried pipe to form a consolidated body, and a plurality of injection pipes are ground at the top of the buried pipe. By embedding in the inside as a support, the solidified body can be fixed to the non-liquefied layer or the surface of the ground, and the floating and rotation of the buried pipe can be more reliably suppressed (Figs. 1, 2, and 3). reference).

  The position where the consolidated body is formed is not necessarily limited to the ground in the upper part of the buried pipe, but may be of any size on the side or bottom of the buried pipe depending on the injection point and the injection amount of the injected material. Can be formed.

  The support is not necessarily an injection tube, and a rod-shaped member such as a reinforcing bar, a steel material, or plastic may be inserted into the ground after the injection tube is pulled out. Further, the injection material is injected into the upper ground of the consolidated body while gradually pulling out the injection tube, and the support is formed by consolidating between the consolidated body and the non-liquefied layer or lining layer of the ground surface layer portion. (See FIGS. 3A, 3B, and 3C).

  In any case, the weight and interval of each consolidated body and the number and interval of supports may be set so as to suppress the floating and rotation of the buried pipe accompanying liquefaction. These supports have a smaller cross section than the consolidated body, have good workability, and do not impair the economy.

  For the injection material, one or more injection materials containing one or more of silica grout solution (colloidal silica-based grout, silica sol-based grout, water glass-based grout), clay, bubbles, cement or slag as active ingredients are used. Can be used.

  Therefore, according to the present invention, even if the periphery of the buried pipe is not continuously consolidated in the tube axis direction of the buried tube, a certain amount of the consolidated body is spaced around the buried tube in the tube axis direction of the buried tube. And forming multiple supports and forming a support between the consolidated body and the non-liquefied layer or lining layer of the ground surface layer, or fixing the upper part of the consolidated body to the non-liquefied layer. (See FIGS. 3 (a), 9, and 10 (a)), the floating and rotation of the buried pipe accompanying liquefaction can be easily suppressed.

  In addition, depending on the expected degree of liquefaction, the diameter and weight of the buried pipe, the weight and interval of the consolidated body and the quantity and interval of the support are set appropriately, thereby raising and rotating the buried pipe. Can be suppressed very effectively.

  In addition, in a lifeline such as a water pipe, sewage pipe, or gas pipe that is laid for several to several tens of kilometers, a solid body is formed little by little along the buried pipe. However, considering the need to move the injection plant, workability, and accurate construction management, there are problems such as inefficiency, but there is a gap in the tube axis direction of the buried pipe. Install multiple injection pipes and place one or multiple injection lines, and simultaneously inject injection material to multiple points through the injection lines to separate the multiple consolidated bodies in the tube axis direction of the buried pipe. By forming it, even if it is a lifeline of several kilometers to several tens of kilometers, the liquefaction countermeasure work can be performed very quickly and efficiently and even more economically while being used. In addition, a very economical liquefaction measure can be taken by integrating the state of the buried pipe, injection design, construction method and construction management.

  In addition, the present inventor has formed a relatively small-diameter solidified body around the buried pipe so as to be integrated with the buried pipe and spaced in the tube axis direction of the buried pipe to increase the weight of the buried pipe and liquefy it. The present invention has solved several problems in preventing it.

  That is, even if the injection material is simply injected into the upper part of the buried pipe and the surrounding area of the buried pipe is solidified integrally with the buried pipe to increase the weight, the center of gravity increases depending on the shape and size of the consolidated body. There is a possibility that the buried pipe may be rotated in the middle of rising due to the liquefaction of the bottom and side parts of the buried pipe and the joint portion of the buried pipe may be detached, or the buried pipe itself may be damaged.

  Alternatively, the consolidated body itself may fall in the ground that has been liquefied by rotation, or individual consolidated bodies may behave differently due to seismic motion during liquefaction, and the buried pipe may rotate.

  In order to prevent this, it is preferable to permeate and solidify the ground around the buried pipe so that the center of gravity of the solidified body integrated with the buried pipe is downward. For this reason, it is necessary to excavate the vicinity of the buried pipe to the bottom or side, install the injection pipe, and inject the injection solution to form a solidified body on the side or bottom. May be damaged.

  If the buried pipe is damaged, the buried pipe that is in service will become unusable, and in some cases, groundwater will flow into the buried pipe, or liquid (such as water and sewage) and gas (gas, etc.) in the buried pipe will be in the surrounding soil. You may be faced with dangerous troubles such as blowing on the ground.

  The present invention has been made to solve the above-described problems. A liquefaction countermeasure work can be safely and effectively performed using a lifeline extending in a linear shape such as a gas pipe, a sewer pipe, a water pipe, and a telephone line. It is possible to do it.

  Furthermore, the present invention relates to a liquefaction countermeasure method for an existing buried pipe, which is performed by injecting an injection material into a peripheral portion of an existing buried pipe installed in the ground where liquefaction is expected, and a plurality of injection pipes are embedded in the buried pipe Installed at intervals in the pipe axis direction of the pipe, injecting the injected material into the ground through the injection pipe, and flowing down the perimeter of the buried pipe, the top, side and / or bottom of the buried pipe The solidified body consisting of the soil surrounding the buried pipe (including backfilled soil) is spaced apart in the tube axis direction of the buried pipe and formed integrally with the buried pipe to increase the weight of the existing buried pipe, and the upper part of the buried pipe By fixing the solidified body to the non-liquefied layer or the lining layer of the surface layer part, it is easy and safe to construct, and economically suppresses the floating of the buried pipe accompanying liquefaction. It is a characteristic (see FIGS. 8 to 13).

  The present inventor has solved the above-mentioned object by utilizing the permeation behavior in the ground of the following chemical solution injection.

  As the most basic osmotic equation regarding the injection pressure and the injection rate, Maag proposes the following equation 1, which is derived from Darcy's law (Non-Patent Document 1 above). "State-of-the-art chemical injection method" published on June 10, 1991 by Shunsuke Shimada, Takeshi Sato, and Minoru Taku (Science and Engineering Books).

  The graph in Fig. 7 shows the relationship between the injection time and the penetration radius in the Maag equation (Non-patent Document 1, P139, Fig. 3.5). In the ground where the groundwater pressure is uniform, the injection material generally penetrates in a spherical shape. (Non-Patent Document 1 P.137).

  In general, osmotic injection is performed so as to consolidate a predetermined region as shown in FIG. 7 (Non-patent Document 1, P.151, Photo 3.6 (a)). By the way, when the gelation time is long, what is solidified in a spherical shape substantially in accordance with the permeation theory at the time of injection is injected and the injectable drug solution is heavier than the ground water, so it flows downward and permeates and solidifies (Non-Patent Document 1). P.152 Photo 3.8, 3.9 Note: The round object in the photo is a stopwatch. This is considered a failure as an injection.

  From this, it can be seen that by setting the gelation time in the soil longer than the injection time of the injection material, the injection material after injection flows down into the ground and forms a consolidated body having a long axis in the vertical direction. (See Figure 12). Alternatively, when the upper layer is laminated with different water permeability in the horizontal direction, a consolidated body is formed in the horizontal direction.

  Therefore, the present inventor has studied the injection time, gelation, and the shape of the consolidated body in chemical solution injection, paying attention to the use of the characteristics of solidification under osmotic flow in Non-Patent Document 1 P152 Photo 3.8 and 3.9. As a result, when injecting an injection material whose gelation time in the soil is longer than the injection time or when the gelation time of the infiltration tip of the injection solution in the soil maintains fluidity even after completion of the injection, The process of (a) → (b) → (c) in FIG. 9 is used to prevent the buried pipe from liquefying by forming a consolidated body by flowing downward after the injection of a predetermined injection amount. Thus, the inventors have conceived that the above problem can be solved.

  Naturally, such a phenomenon is likely to occur in the ground where liquefaction is likely to occur because the density is lower and the water permeability is higher than that of the non-liquefied layer. Further, according to such a technique, the shape of the consolidated body can be infiltrated and consolidated so that the center of gravity is located below.

  If the above chemical solution is poured into the ground so that the embedded tube is included in the infiltration consolidation range of the chemical solution in this ground (see Figs. 10, 11, and 12), the drilling depth of the injection tube reaches the bottom and sides. The present invention has been completed by paying attention to the fact that a consolidated body can be formed on the upper part, side part or lower part of the buried pipe without this.

  Also, if the buried pipe is laid at a relatively shallow position near the non-liquid purification layer on the ground surface layer, the consolidated body should be formed so that its upper end is fixed in the non-liquefied layer. Therefore, it is possible to prevent the buried pipe from rising during an earthquake or the like with a simple, safe and stable consolidated body (see FIGS. 3 (a) and 10 (a) to (d)).

  In addition, when the buried pipe is laid at a relatively deep position, a certain area of the upper ground of the consolidated body is consolidated into a column shape continuous in the vertical direction, and its lower end is continuous with the consolidated body. In addition, the upper end may be fixed in the non-liquefied layer to form a support (see FIGS. 3 (b), (c), FIGS. 12 (a), (b), (c)).

  Furthermore, the injection tube 2 used for forming the consolidated body 12 and the support body 13 is inserted into the support body 13, or a reinforcing bar or steel material is inserted separately from the injection tube to reinforce the support body 13. You can also In this case, it is desirable that the tips of these members are fixed in the solidified body 12, and the upper ends are fixed in the non-liquefied layer and the asphalt pavement 11 (see FIGS. 12 (a), (b), and (c)).

  In this way, construction can be performed while maintaining the safety of drilling around the buried pipe, and a solid body integrated with the buried pipe can be formed. Therefore, the buried pipe is not damaged or deformed. Of course, construction is also easy.

  In particular, in the case of loose ground such as backfill ground after excavating and installing non-liquefied ground like the buried pipe, the chemical solution will spread downward if there is a non-liquefied layer below the buried pipe Since it tends to permeate and solidify, it can gradually spread downward while maintaining the gelation time and maintain fluidity, and can form a solidified body that is stable against earthquakes and the like (see FIG. 9 (c)).

  In addition, it is possible to inject a chemical solution with a single injection tube in principle at each injection point (see Figure 10 (a) and (b)). If necessary, multiple injection tubes can be connected at one injection point. It is also possible to use (see two-point injection, FIG. 10 (c), FIG. 12 (c)).

  In addition, when the injection pipe is installed at the upper part of the buried pipe and allowed to flow down and penetrate only into the upper part of the buried pipe, the injected material is allowed to flow down and penetrate continuously from the upper part and upper part of the buried pipe to the side of the buried pipe, or When the injection pipe is installed on the side of the buried pipe and allowed to flow down and penetrate only to the side of the buried pipe, it may be continuously penetrated from the side of the buried pipe and the side of the buried pipe to the bottom of the buried pipe. is there.

  Further, there is a case where the injection pipe is installed on the upper part of the buried pipe and is continuously permeated down from the upper part of the buried pipe, from the upper part of the buried pipe to the side of the buried pipe, and further from the side of the buried pipe to the bottom part. It is also possible to insert the injection tube up to the bottom of the buried tube and continuously infiltrate it down from the bottom of the buried tube and the bottom of the buried tube over a certain range below.

  Which method is to be adopted may be selected according to the size (outer diameter) of the buried pipe and the properties of the surrounding ground.

  FIG. 12 (b) shows an example in which the infusion is permeated down from the upper injection pipe of the buried pipe by two-point injection to form a consolidated body on the upper part of the buried pipe and integrated with the buried pipe. Since the drilling of the buried pipe does not reach the buried pipe, there is no risk of the buried pipe being damaged.

  In addition, an infusion solution with a long gelation time is injected at a low discharge speed. Can be formed.

  In addition, the buried pipe is located at a relatively shallow depth on the ground surface. In normal injection, the injected liquid escapes to the ground surface, or if the injection speed is high, the ground is displaced and the buried pipe is deformed. (See Figure 27). On the other hand, the present invention can solve the above problem by performing simultaneous injection at a low discharge speed or continuous injection at a low pressure as shown in FIGS.

  Here, the gelation time in the soil refers to the gelation time in the soil penetrating into the ground, not the gelation time at the time of blending in the above-ground part. Since the injection solution is affected by the pH of the injection solution, the pH of the soil and the composition in the ground, it differs from the gelation time on the ground. For this reason, it mix | blends with an injection liquid using collection soil, and measures the gel time in soil.

  Or, for example, a 1m long vinyl pipe is filled with soil collected from the site at a predetermined density, the injection solution is injected, the gel time of the injection solution flowing out from the tip is measured, and the gel time of the infiltration tip in the soil is measured. The composition of the injection solution can be set. In this way, it can be seen how much fluidity of the injected liquid maintains gelation even when the injection is completed.

  As described above, in the present invention, the injection liquid is solidified in the ground by osmosis and solidification in the ground so that the existing embedded pipe is included, and when the injection material is injected, through the injection pipe inserted from the ground around the embedded pipe. The injection material is injected into the ground at the top of the buried pipe, and the injected material flows down into the top, sides and / or bottom of the buried pipe to form a solid body integrated with the buried pipe to reduce the weight of the existing buried pipe. By increasing it, the floating of the buried pipe accompanying liquefaction can be suppressed.

  Also, by forming the center of gravity of the consolidated body integrated with the buried pipe so that it is located below the center of gravity of the buried pipe before injection, the buried pipe is prevented from floating, rotating, twisting, etc. during liquefaction. (See FIG. 12).

  In addition, by making the gelation time in the soil longer than the injection time of the chemical solution, or injecting so that the fluidity is maintained even when the injection is completed, Thus, the injected material is allowed to flow down and solidify to the side and below the buried pipe, so that a solid body having a stable shape can be formed even during liquefaction integrated with the buried pipe.

  Furthermore, it is formed by the size and weight of the consolidated body formed in the peripheral portion of the buried pipe, the interval between the consolidated bodies, and the amount of the chemical solution to be injected into one consolidated region and the injection of the chemical solution. By setting the shape of the solidified body and the volume of the solidified body, as well as the injection time, injection speed and gelation time of the chemical solution, the optimal shape, optimal size and optimal By forming the heavy solid body integrally with the buried pipe, it is possible to suppress the floating of the existing buried pipe accompanying liquefaction.

  FIG. 13 illustrates a method for suppressing floating due to liquefaction of the buried pipe by forming a consolidated body at the top of the buried pipe by one point injection to increase the weight of the buried pipe. In this case, by injecting the injection material so that the consolidated body spreads symmetrically on both sides of the buried pipe, it is possible to prevent rotation or the like accompanying the floating of the buried pipe.

  FIG. 14 also illustrates a method of suppressing floating due to liquefaction of the buried pipe by forming a consolidated body on both sides of the buried pipe by two-point injection to increase the weight of the buried pipe. In this case, it is possible to efficiently increase the weight of the buried pipe by injecting the injection material at two points so that the consolidated bodies on both sides are symmetrically expanded in diameter. It is possible to more reliably prevent the rotation and the like associated with.

  In general, buried pipes such as gas pipes, water pipes, and sewage pipes are laid while excavating the ground that is not easily liquefied into grooves, and then backfilled with excavated soil. For this reason, the backfill soil at the upper part of the buried pipe is loose and easy to liquefy.However, by injecting the chemical solution into the ground above the buried pipe, It permeates through the liquefied ground to form a consolidated body. In particular, in order to form a consolidated body in which a certain range of backfill soil and non-liquefied ground outside it is integrated (see dashed lines in Fig. 11 (a) and (b)), anchors of non-liquefied ground Due to this effect, the effect of suppressing the floating of buried pipe is extremely large.

  Furthermore, a plurality of injection pipes are installed at intervals in the tube axis direction of the buried pipe (see FIGS. 12 (a), (b), (c)), and chemical solutions are continuously or simultaneously supplied to the plurality of injection points. By injecting and rapidly forming a consolidated body at each injection point, lifelines that extend in a line over several kilometers to several tens of kilometers, such as gas pipes, sewer pipes, water pipes, and telephone lines Measures for liquefaction can be performed very efficiently and effectively while using buried pipes. In particular, the effect is doubled by performing two-point injection with two injection tubes at one injection point as shown in FIG.

  The formation of the solidified body in the present invention is largely related to the penetration range and the gelation time of the chemical solution. Regarding the relationship between the penetration range of the chemical solution and the gelation time in the injection of the chemical solution, the penetration range is the gelation time. In addition, injection pressure, injection speed, injection volume, injection time, injection hole diameter, injection method and ground permeability, porosity, void development, injection viscosity, etc. are related to each other. By setting the value appropriately in accordance with the properties, an optimally large and optimally shaped consolidated body can be formed around the existing buried pipe by interparticle penetration.

  Actually, it is related to inhomogeneous ground conditions, groundwater flow, clay change in the injection material, complex infiltration mechanism of fluid with gelation, etc. Although it is difficult, after trying the test injection around the buried pipe, it is possible to grasp the shape of the infiltration consolidated body corresponding to the injection condition and the ground condition by sounding and reflect it in this construction.

  The chemical injection method can be applied without excavating the ground, and is excellent in that it can be applied to existing buried pipes.However, considering that the chemical is expensive, the range of solidification improvement and its pipeline Development of technology that integrates the layout and construction method is necessary.

  Therefore, the present inventor has studied the amount of the chemical solution necessary for suppressing the floating of the buried pipe, and has studied the effective injection method even with a small amount, thereby completing the present invention. In addition, liquefaction countermeasures that form a consolidated body at intervals along a linear pipeline to form a consolidated body, enabling minimal and effective injection economically and rapidly. Was invented (see FIGS. 9 to 14).

  The main points of the present invention obtained by a large soil tank liquefaction experiment (see FIG. 23) described later are as follows.

(A) In the liquefaction countermeasure method for existing buried pipes installed in the ground where liquefaction is expected, a plurality of injection pipes are installed at intervals in the extension direction of the buried pipes, and the buried pipes are passed through the injection pipes. The chemical solution is injected into the ground on the top or side, and the chemical solution flows down and penetrates the side and / or bottom of the buried pipe, and the surrounding soil (backfill soil, etc.) of the buried pipe is placed on the side and / or bottom of the buried pipe. It is characterized by suppressing the floating of the buried pipe due to liquefaction at the time of earthquake by forming a consolidated body made of and integrally with the buried pipe to increase the weight of the buried pipe, and accompanied by the following method Can do.

(1) A method in which the buried pipe is fixed to the non-liquefied layer of the original ground to prevent the existing buried pipe from rising during an earthquake.
(2) A method to solidify the backfill soil under the buried pipe and prevent the buried pipe from rising due to the soil in the non-liquefied layer falling to the left and right or the top during an earthquake.

(B) In the above, set F = (gravity applied to the tube and consolidated soil) / (buoyancy applied to the tube and consolidated soil), the amount of consolidated body in the extension direction of the buried tube, and the consolidated Set the spacing between bodies. Here, F is a liquefaction countermeasure method set as follows.

(1) When the surrounding ground is liquefied,
Safety factor F ≧ 0.7 (preferably F ≧ 0.8).

  From Fig. 15, if F≥0.7, the floating amount is significantly reduced at 10mm or less, and it is considered that there is almost no problem in practical use.From Fig. 15, the volume of the improved consolidated body by chemical solution is the volume of the buried pipe It is about twice as much and is economically preferable.

  15 and 16, it can be seen that if F ≧ 0.8, the floating amount is 0 and there is no problem, and the volume of the consolidated body is only about 2.5 times the volume of the buried pipe, which is extremely economical. .

(2) When only the backfill part is liquefied,
(I) When consolidating the upper part of the buried pipe,
Safety factor F ≧ 0.7
(Ii) In the case where the buried pipe and the consolidated part are fixed to the side part and / or the bottom part of the non-liquefied layer,
Safety factor F ≧ 0.6 (preferably F ≧ 0.7).

  14 and 18, if it is integrated with the buried pipe and fixed on the side or / and bottom of the non-liquefied layer (two-point injection), the floating rate will be greatly reduced if the safety factor F ≧ 0.6. It turns out that it hardly arises. In this case as well, if F ≧ 0.7, there will be no lift.

(C) In the above, F is set as follows.
F (safety factor) = (AVpipe + BVsolidified) / (CVpipe + CVsolidified)
= (A + B (Vsolidified / Vpipe)) / (C + C (Vsolidified / Vpipe))

However, A: Density of buried pipe, to be precise, average density of pipe body including inside of pipe (example: 0.50 g / cm ³ ), B: density of consolidated soil (example: 1.85 g / cm ³ ), C : Density of muddy water during liquefaction (example: 1.81 g / cm ³ ), tube volume: Vpipe, solidified soil volume: Vsolidified

  If the safety factor is ≧ 1 as in the conventional idea, it was necessary to improve the sand 33 times the volume of the buried pipe. It has been found that the body can prevent levitation due to liquefaction.

(D) In the above, the consolidated body is formed at a predetermined interval, and the consolidated body is formed by any of the following methods.

(1) Method of injecting from the injection pipes provided on both sides of the buried pipe and fixing the buried pipe to the non-liquefied layer of the original ground (preferably injected from the injection pipe provided on both sides of the buried pipe, but one side May be fixed to the non-liquefied layer on the side surface or bottom surface of the original ground from the injection pipe.

(2) A method of injecting from one side of the buried pipe and consolidating the backfill soil at the bottom of the buried pipe to integrate the buried pipe and the consolidated body.
If the backfill soil at the bottom of the buried pipe is solidified, even if the non-liquefied layer on the side collapses and falls during an earthquake, it will not enter the bottom of the buried pipe, but will fall into the top of the buried pipe and prevent the buried pipe from rising (Fig. 20).

(3) A method of injecting into the upper part of the buried pipe and integrating the buried pipe and the consolidated body to increase the gravity applied to the buried pipe and the consolidated body.

(E) In the above, the amount of consolidation in the extending direction of the buried pipe and the interval between the consolidated bodies are determined so that the safety factor F ≧ 0.8 or the safety factor as described above. There is no problem if the safety factor is 0.8 or more in any condition.

  Of course, in the above, where the reaction force against the levitation can be expected at the connection portion with the buried pipe, the manhole, the drain pipe, etc., it becomes more difficult to levitate even for the same safety factor F value.

(F) A plurality of injection pipes are arranged at predetermined intervals along the periphery of the laying object laid in a line, the injection line laid in a line, or the periphery of the structure. It is connected to a liquid supply pipe via a path conversion valve. The liquid supply pipe is equipped with an injection pump equipped with a pressure / flow meter and an injection material storage tank. Then, the flow is switched to the injection pipe and injected (see FIGS. 25 (a), 26 (a), 32 (a), and 35).

(G) The injection pipe is connected to a liquid feeding pipe via an orifice, and the liquid feeding pipe is equipped with an injection pump equipped with a pressure / flow meter and an injection material manufacturing apparatus, and simultaneously or selectively to a plurality of injection pipes. (See FIGS. 25 (b), 28, 29, 32 (b), 33 (a), (b), and 34)).

(H) A plurality of injection pipes are arranged at predetermined intervals along the periphery of the laying object laid linearly or the injection line laid linearly or the structure. Each unit pump communicates with a plurality of infusion lines, and the operation of each unit pump is collectively managed by the controller based on information from the pressure flow measurement of the plurality of unit pumps (FIGS. 26 (b) and 36). FIG. 37 (b)).

[Experiment 1]
As shown in Table 1, the inventors conducted a comparative experiment (Case 1 to 3) in which the injection amount was changed and a comparative experiment (Case 4 to 7) in which the injection method was changed.

1. Outline of Experiment A ground with a depth of 50 cm, width of 270 cm, and depth of 40 cm was created using No. 7 sand with a maximum gap ratio of 1.104 and a minimum gap ratio of 0.673 (see Fig. 23). The ground was prepared by wet compaction, and the density was controlled every 5 cm.

  The buried pipe model was a vinyl chloride pipe with an outer diameter of 6 cm, a length of 35 cm, a hollow inside and a density of 0.50 g / cm3, and was installed at a depth of 33 cm in the center of the soil tank. The input acceleration shown in FIG. 6 is used, and its frequency is 10 Hz.

  The amount of floating of the buried pipe was measured with a winding displacement meter, and an accelerometer and a water pressure meter were installed in the soil. Colloidal silica was used for the chemical solution. The siphon principle was used for the injection of the chemical solution, and osmotic injection was performed using the water head difference.

  Considering that the injection method spreads around the buried pipe, select the two types shown in Figs. 13 and 14, one point injection from the top of the buried pipe, and two point injection from the left and right. . The injection tube was installed during ground preparation and removed after the chemical solution was injected (see FIGS. 23 and 24).

  In addition, when the chemical solution was injected into No. 7 cinnabar, the gel time was longer than 1 day, and the chemical solution with a higher specific gravity than water would hang down. The experiment was conducted by mixing the magnesium to shorten the gel time to about 1 hour.

2.Comparison experiment of injection volume
2.1. Content of Experiment In the comparison experiment (Cases 1 to 3) of the injection amount, the ground was prepared with a relative density of 30% so that the entire ground in the soil tank was liquefied. There were three types of injections, 0ml, 500ml, and 1000ml, and all the chemicals were injected by a single point injection method. These experimental cases were performed simultaneously by installing three buried pipes in the ground at intervals of 40 cm (see Table-1, Figure 15, and Figure 24 (a)).

2.2 Experimental results and discussion Figure 15 shows the results of the injection volume comparison experiment. The safety factor in the figure is a value obtained by dividing the gravity applied to the buried pipe and the entire solidified sand around it by the buoyancy during the experiment, and the smaller one is more likely to rise. In addition, the weight and volume of the solidified improved sand were measured when excavating the ground at the end of the experiment. From this figure, it can be seen that if the safety factor is 0.80, the levitation of the buried pipe will be zero and even 0.7 will have the effect of reducing the levitation. Buried pipe Density A: 0.50g / cm ^3, the solidified sand B: 1.85g / cm ^3, mud during liquefaction C: was 1.81 g / cm ^3, the volume of the tube Vpipe, solidified sand If the volume is Vsolidified,
Safety factor F = (A Vpipe + B Vsolidified) / (C Vpipe + C Vsolidified)
= (A + B (Vsolidified / Vpipe)) / (C + C (Vsolidified / Vpipe))
It becomes.

  FIG. 16 is a graph in which the vertical axis represents the safety factor and the horizontal axis represents Vsolidified / Vpipe. From the figure, it is necessary to improve the sand that is about 33 times the volume of the buried pipe in order to increase the amount of the chemical solution and increase the safety factor to 1.0 or more.

  On the other hand, 0.9 is about 5 times, 0.8 is about 2.5 times, and 0.7 is about 2.0 times the volume of sand.

3.Comparison experiment of injection method
3.1.Experimental details As shown in Fig. 17, assuming the condition that only the backfill part around the buried pipe liquefies, the relative density is 30% only in the range of 35cm depth and 25cm width in the center of the earth tub, otherwise The ground was made to be 80%.

  A total of three case experiments were conducted, in which the chemical solution was injected by the two types of injection methods shown in FIGS. In these experiments, when the lift stops completely in all cases, comparison by injection method cannot be made. Therefore, the injection amount of the chemical solution was uniformly set to 500 ml so that the difference becomes clear. In addition, colored sand colored with No. 7 dredged sand was placed vertically and horizontally on the wall surface of the soil tank so that the movement of the sand during vibration could be seen (see Figs. 21 and 22).

3.2. Experimental results and discussion Figure 18 shows the results of the injection method comparison experiment. From this figure, it can be seen that two-point injection is an effective injection method. The reason is that the chemical solution spreads to the bottom of the buried pipe as shown in FIG. 19, and it is considered that the floating of the buried pipe was suppressed by fixing on the lower non-liquefied layer. The chemical solution spreads to the upper part of the buried pipe at one point injection, so it seems that it has risen greatly because there was no fixation on the non-liquefied layer.

  In addition, when liquefaction occurs, it is considered that the boundary wall surface between the backfill portion and the surrounding ground collapses into a liquefied layer having lost rigidity as shown in FIG. Since the bottom of the buried pipe is not solidified by one-point injection, it was confirmed from the colored sand on the wall surface of the soil tank after the experiment that the amount of floating increased by the sand that collapsed at the same time as entering the buried pipe. (See FIG. 21). On the other hand, in the two-point injection, it was confirmed that the sand could not go under the buried pipe and the floating of the buried pipe was suppressed by collapsing left and right or above (see FIG. 22).

  Furthermore, it has been experimentally observed that the amount of sand to solidify is less than that of other methods because the center of gravity becomes higher due to the solidification of the chemical solution at the upper part of the buried pipe in one point injection, and rotation can occur during the rising. . From the above, it was found that the two-point injection is the most effective injection method when the surrounding ground is non-liquefied.

  In addition, the present invention is a technique for performing the above-described implantation rapidly and effectively along the lifeline. Lifelines such as buried pipes are performed under conditions where roads, residential areas, etc. are always in service.

  In addition, it is important to ensure safety because work is performed in cities with heavy traffic. For this reason, the present invention has been completed in consideration of the following points.

(1) It is preferable to be performed fully automatically without touching. Furthermore, there is a need for a device that can be used as a compact on-board plant that can be mounted on a vehicle and moved along a road (see FIG. 25). An example of such an injection liquid production system is shown in FIG.

(2) Since it is intended for long-distance lifelines such as roads, revetments, residential land, etc., a system that can simultaneously or continuously send from a manufacturing plant to a long-distance injection point through a liquid feed pipe is required. .

  And once an injection system is installed, it is preferable that construction is automatically performed even when the lifeline is in service. If the injection plant is moved at each injection point as in normal injection construction, traffic must be interrupted each time.

  According to the present invention, it is possible to work on a plurality of points at the same time or continuously without moving a construction site over a long distance, without having to move over a wide range, without stopping the lifeline. The injection operation can be performed (see FIGS. 25, 26, 36, and 37).

  The infusion liquid production system of FIG. 37 (a) is composed of a plurality of cylinder pumps for sucking and discharging the raw material liquid by the liquid feed pump, and the suction and discharge of the plurality of cylinder pumps are synchronized within the same time. A control mechanism for controlling is provided.

  In addition, liquid can be directly fed to a plurality of liquid feeding pipes from these cylinder pumps (see FIG. 37 (b)). This device can be manufactured safely in an on-board plant because it can produce injection with a compact control device (Fig. 6).

  According to the present invention, a solidified body is formed on the upper part of the existing buried pipe to give a predetermined weight to the buried pipe, and between the solidified body and the non-liquefied layer or the lining layer of the ground surface layer portion. By forming the support so as to support the buried pipe from the top to the bottom, not only can the floating of the buried pipe accompanying liquefaction be suppressed, but also the buried pipe that is likely to occur with the floating of the buried pipe accompanying liquefaction. Rotation can also be prevented.

  In addition, liquefaction countermeasures such as gas lines, water pipes, and sewage pipes in residential areas such as subdivisions where roads and detached houses are densely built can be easily and economically performed. In particular, it is possible to suppress the floating of existing burial during liquefaction. In addition, the liquefaction countermeasure of the present invention can be performed while using a lifeline.

  Furthermore, when the chemical solution is injected, the size and weight of the consolidated body formed in the peripheral portion of the buried pipe, the interval between the consolidated bodies, the amount of the chemical solution injected into one consolidated region, and the chemical solution By setting the shape and volume of the consolidated body, the injection time of the injection solution, the injection speed of the chemical solution, the gelation time, etc., the optimal shape and the optimal size of the consolidated body are buried according to the properties of the ground. , The floating of the existing buried pipe accompanying liquefaction can be suppressed.

1 shows an existing buried pipe reinforced by a liquefaction countermeasure method for an existing buried pipe of the present invention, FIG. 1 (a) is a cross-sectional view of the existing buried pipe, and FIG. 1 (b) is a partial side view. It is a cross-sectional view of the other existing buried pipe reinforced by the liquefaction countermeasure method for the existing buried pipe of the present invention. Fig. 3 shows an existing buried pipe reinforced by a liquefaction countermeasure method for an existing buried pipe according to the present invention, Figs. 3 (a) and (b) are cross-sectional views of the existing buried pipe, and Fig. 3 (c) is a partial side view. is there. 4 (a) to 4 (f) are cross-sectional views of the existing buried pipe showing the construction procedure of the liquefaction countermeasure method for the existing buried pipe of the present invention. Figures 5 (a) and 5 (b) are cross-sections showing the buried pipe and the solid body formed integrally with the buried pipe in the upper ground of the buried pipe being displaced and rotated in the muddy water under the seismic force. FIG. It is a graph which shows input acceleration. It is a graph which shows the relationship between the injection | pouring time and penetration radius in Maag's formula. It is explanatory drawing which shows the osmosis | permeation state of the injection material in the ground where a groundwater pressure is uniform. FIGS. 9 (a) to 9 (c) are explanatory diagrams showing a state where the injecting material solidifies by flowing down when the gel time in the soil is longer than the pouring time. FIGS. 10 (a) to 10 (d) are explanatory views showing a state in which the injection material flows down and solidifies around the buried pipe laid in the relatively shallow liquefied ground close to the non-liquefied layer. . FIGS. 11 (a) to 11 (c) are explanatory diagrams showing a state in which the injected material permeates down and solidifies around the buried pipe laid in the relatively deep liquefied ground separated from the non-liquefied layer. is there. Fig. 12 (a) shows the liquefaction countermeasure method for existing underground pipes by injecting multiple chemicals into the upper ground of existing underground pipes at intervals in the axial direction. FIG. 12 (b) is a side view, and FIG. 12 (c) is a cross-sectional view in the direction perpendicular to the tube axis in FIG. 12 (a) showing chemical injection by one-point injection and FIG. 12 (c) showing chemical injection by two-point injection. It is explanatory drawing which shows the injection method by one point injection | pouring. It is explanatory drawing which shows the injection method by 2 point | piece injection. It is a graph which shows the result of an injection | pouring amount comparison experiment. It is a graph which shows the relationship between the improvement range and a safety factor. It is explanatory drawing which shows the outline | summary of the comparative experiment of an injection | pouring method. It is a graph which shows the result of the comparison experiment of an injection | pouring method. It is explanatory drawing which shows the fixation state to the non-liquefaction ground of a buried pipe. 20 (a) and 20 (b) show the movement of sand during liquefaction, FIG. 20 (a) is an explanation before liquefaction, and FIG. 20 (b) shows the state after liquefaction. It is a figure which shows the soil tank wall surface after the vibration of the soil tank injected by one point. It is a figure which shows the soil tank wall surface after the vibration of the soil tank in which 2 points | pieces were inject | poured. FIG. 23 (a) is a front view and FIG. 23 (b) is a plan view showing an outline of a large soil tank experimental apparatus. It is explanatory drawing which shows the outline | summary of a preliminary experiment. FIG. 25 (a) is an explanatory view showing a construction example, and FIG. 25 (b) is an explanatory view showing another construction example. FIGS. 26 (a) and 26 (b) are explanatory diagrams showing a construction management system using a liquid feeding system and a displacement sensor. It is explanatory drawing which shows the relationship between the injection | pouring speed | rate and the limiting injection | pouring speed | rate by injection | pouring pressure. It is explanatory drawing which shows the supply principle of the injection liquid by an orifice. FIG. 29 (a) is an explanatory diagram showing the relationship among the liquid feed pressure (P ₀ ), the nozzle diameter (a), the ejection amount, and the permeation resistance pressure of the ground, and FIG. 29 (b) is the permeation resistance pressure P ₁ = 0. It is a graph which shows the relationship between the liquid feeding pressure in this case, a nozzle diameter, and the amount of ejection. FIG. 30 (a) is a graph showing the relationship between the ejection amount, the nozzle diameter and the differential pressure, and FIG. 30 (b) is a graph showing the relationship between the permeation resistance pressure, the nozzle diameter and the ejection amount. FIG. 31 (a) is a graph showing the relationship between the liquid feeding pressure, the permeation resistance pressure, and the ejection amount, and FIG. 31 (b) is a graph showing the relationship between the liquid feeding pressure, the nozzle diameter, the number of nozzles, and the ejection amount. FIG. 32 (a) is an explanatory diagram showing an example of a basic liquid delivery system, and FIG. 32 (b) is an explanatory diagram showing another example of the basic liquid delivery system. FIG. 33 (a) is an explanatory diagram showing still another example of the basic liquid delivery system, and FIG. 33 (b) is an explanatory diagram showing still another example of the basic liquid delivery system. It is explanatory drawing which shows the further another example of a basic liquid feeding system. FIG. 35 (a) is an explanatory view showing an example of a system for continuously or selectively delivering liquids to a plurality of injection locations, and FIG. 35 (b) is a system for continuously or selectively delivering liquids to a plurality of injection locations. It is explanatory drawing which shows the other example. It is explanatory drawing which shows the system which delivers an injection liquid to a some injection | pouring point simultaneously or selectively. FIGS. 37 (a) and 37 (b) are explanatory views showing a fully automatic production apparatus for an injection solution.

  1 and 2 illustrate an existing buried pipe reinforced by the liquefaction countermeasure method of the present invention, and the buried pipe 1 may be liquefied because the surface layer portion of the ground is covered with asphalt pavement 11. It is laid in the ground.

  Further, a consolidated body 12 is formed in the upper ground of the buried pipe 1, a support body 13 is formed in the upper ground of the consolidated body 12, and a support plate 14 is supported on the upper end portion of the support body 13. It is formed integrally with the body 13 and the asphalt pavement 11.

  The consolidated body 12 is formed to give a predetermined weight to the buried pipe 1 and to suppress the floating of the buried pipe 1 due to liquefaction, and injects an injection material into the upper ground of the buried pipe 1. Then, a plurality of areas are formed at intervals in the pipe axis direction of the buried pipe 1 by permeating and consolidating the ground in a certain region above the buried pipe.

  The size, shape, interval, and the like of the consolidated body 12 are appropriately determined in consideration of the liquefaction of the ground around the buried pipe and the weight of the buried pipe 1 that are expected in the event of an earthquake. Further, the consolidated body 12 is not necessarily formed in the ground above the buried pipe, and may be formed at one or a plurality of positions on the side or bottom of the buried pipe 1.

  The support 13 is formed to suppress the floating of the buried pipe 1 due to liquefaction and the rotation of the buried pipe 1 that is likely to occur simultaneously with the floating by supporting the buried pipe 1 from above to below. A plurality of buried pipes 1 are formed at intervals in the pipe axis direction.

  Further, the support 13 is formed by leaving the injection tube 2 inserted into the upper ground of the buried pipe 1 to form the consolidated body 12 without being collected, and burying it in the ground. A support plate 14 made of asphalt is formed integrally with the support 13 and the asphalt pavement 11 at the upper end of the slab, and thereby, the support 13 is provided with a supporting force against lifting and rotation accompanying the liquefaction of the buried pipe 1. ing.

  Further, as shown in FIG. 2, the consolidated body 12 is formed wider than the outer diameter of the buried tube 1 in the direction perpendicular to the tube axis of the buried tube 1, and the support 13 is spaced in the direction perpendicular to the tube axis of the buried tube 1. By opening and forming a plurality, the effect of suppressing the floating and rotation of the buried pipe accompanying liquefaction can be further increased.

  The number, diameter, interval, etc. of the support 13 are appropriately determined in consideration of the liquefaction of the ground around the buried pipe and the weight of the buried pipe 1 as expected in the event of an earthquake. Yes. The support 13 can also be formed by inserting a rod-shaped member such as a reinforcing bar or steel into the ground after the injection tube 2 is pulled out.

  Further, as shown in FIGS. 3 (a) to 3 (c), when the buried pipe 1 is laid at a relatively shallow position close to the non-liquid purification layer, the solidified body 12 is connected to the upper end portion thereof. Is fixed to the non-liquefied layer (see FIG. 3 (a)), or a certain region of the upper ground of the consolidated body 12 is consolidated into a columnar shape, and its lower end is consolidated into the consolidated body 12 And the upper end portion may be fixed in the non-liquefied layer to form the support 13 (see FIGS. 3B and 3C).

  Further, the injection tube 2 used for forming the consolidated body 12 and the support body 13 is inserted and embedded in the support body 13, or a reinforcing bar, a steel material, or the like is inserted separately from the injection tube and the support body 13 is inserted. Can be reinforced. In this case, it is desirable that the tips of these members are fixed in the solidified body 12, and the upper ends are fixed in the non-liquefied layer and the asphalt pavement 11.

  In addition, in the Example of FIGS. 1-3, although the case where the surface layer part of the ground was asphalt pavement was explained, even if the surface layer part of the ground is concrete pavement, it can be constructed with substantially the same configuration, In the case of concrete pavement, the bearing plate 14 in FIG. 1 may be constructed with concrete.

Explaining the construction method (see Fig. 4 (a) to (f)),
(1) First, holes 11a and 11a are formed in the asphalt pavement 11, and the injection pipes 2 and 2 are inserted into the ground above the buried pipe from the holes 11a and 11a.

(2) Next, the injection material is injected into the ground above the buried pipe 1 through the injection pipes 2 and 2, and the ground at the top of the buried pipe 1 is permeated into the ground above the buried pipe 1. Consolidate to form consolidated bodies 12,12.

(3) Next, the upper ends of the injection pipes 2 and 2 are cut and removed from the vicinity of the lower end of the asphalt pavement 11 in the holes 11a and 11a, respectively. The holes 11a and 11a are filled with asphalt, and the support plates 14 and 14 are formed integrally with the injection pipes 2 and 2 and the asphalt pavement 11 at the upper ends of the injection pipes 2 and 2, respectively. , 2 is given a supporting force against the floating and rotation of the buried pipe 1. Construction is completed by the above process.

  The examples shown in FIGS. 32 (b), 33 (a), (b) and FIG. 34 are optional for a plurality of branch pipes provided in a liquid supply pipe line from an injection liquid production apparatus to an injection point. An orifice provided with a hole having a diameter of 5 mm was provided. As a result, it is possible to supply and inject a predetermined amount of injection solution into a plurality of injection locations.

  In the figure, reference numeral 1 denotes an existing buried pipe such as a water pipe, a sewage pipe, a gas pipe laid in the ground, 2 denotes an injection pipe for injecting an injection liquid (chemical solution) around the existing buried pipe 1, 3 Is an injection liquid production apparatus.

  Reference numeral 4 denotes a pressure feed pump for feeding the injection solution into the injection tube 2 at each injection point, 5 denotes a branch valve for controlling the flow path of the injection solution at each injection point, and 6 denotes the injection solution at each injection point. An orifice for measuring the flow rate, and a reference numeral 7 is a controller for controlling them.

  FIG. 25 shows an example in which the above apparatus is mounted on the vehicle 8, and a predetermined amount of injection solution can be simultaneously or selectively sent to a plurality of injection locations while moving.

  Furthermore, in the further construction method of the present invention (see FIGS. 26 (b) and 36), the injection liquid manufactured by the injection liquid manufacturing apparatus 3 is sent to a plurality of injection locations via a plurality of unit pumps 9. In addition, by collectively controlling the driving of the plurality of unit pumps 9 by the controller 7, the injection solution can be supplied and injected into the plurality of injection locations simultaneously or selectively.

  In the figure, reference numeral 10 denotes a ground displacement sensor for monitoring an abnormal bulge of the ground accompanying injection of the injection liquid, and is managed by the controller 7.

  Furthermore, still another construction method of the present invention is such that the injection liquid manufactured by the injection liquid manufacturing apparatus 3 passes through one branch pump 4 and a plurality of branch valves 5 from the liquid supply pipe line. By supplying the liquid to a plurality of injection locations and operating the plurality of branch valves 5, the injection solution can be supplied and injected continuously or selectively into the plurality of injection locations (FIG. 25 (a), (b), Fig. 26 (a), Fig. 32 (a), (b), Fig. 33 (a), (b), Fig. 34, Fig. 35 (a), (b)) The same applies when there is no orifice).

  In the construction method, by extending the injection pipe line from the injection liquid production apparatus 3, the lifeline can be provided without moving the injection liquid production apparatus 3 for each of the plurality of injection points while the plant is installed at one place. Injecting construction can be performed while making it possible to use the equipment, so that rapid construction is possible even when applied to roads and residential land, etc., and the roads and railways in the vicinity of the application location are always in service. (See FIGS. 26 and 35).

  Still another construction method of the present invention uses the infusion solution produced by the infusion solution production apparatus 3 while mounting the infusion solution production apparatus 3 on the vehicle 8 and moving the vehicle 8 along the lifeline. Rapid construction is possible (see Fig. 25).

  Further, according to the present invention, it is possible to provide a liquefaction countermeasure work that is excellent not only in economic construction but also in terms of workability and environmental performance.

FIG. 29 shows the relationship among liquid feed pressure (P _O ), nozzle diameter (a), ejection volume (liter / min), and permeation resistance pressure (P ₁ ) in a pipe line provided with an orifice.

  FIG. 29 (a) shows the test apparatus, in which a pipe line having a nozzle diameter (a) is inserted into the outer pipe, packers are provided on both sides of the nozzle, and a pressure regulating valve is installed in the pipe line from the outer pipe. This is a structure for adjusting the opening of the pressure regulating valve.

Pump the liquid into the pipeline and measure the pressure (P ₀ ) and flow rate. The pressure and flow rate of the liquid ejected from the nozzle diameter (a) are measured by adjusting the opening of the pressure regulating valve. The pressure P1 at that time is the permeation resistance pressure, and the flow rate at that time is the ejection amount.

FIG. 29 (b) shows the relationship between the liquid supply pressure (P ₀ ), the nozzle diameter (a), and the ejection amount when the pressure regulating valve is fully opened, that is, when liquid is supplied in the air. When the pump pressure P ₀ is constant, the pressure is higher as the nozzle diameter is smaller, and the ejection amount is larger as the nozzle diameter is larger.

FIG. 30 (a) shows the relationship between the nozzle diameter (a) of the orifice, the differential pressure ΔP, and the ejection amount per minute. The differential pressure ΔP refers to the difference between the pumping fluid pressure P ₀ and the resistance pressure P ₁ downstream of the orifice. The larger the differential pressure and the larger the nozzle diameter, the larger the ejection amount. As the resistance pressure P ₁ increases and approaches the liquid feeding pressure P ₀ , the ejection amount approaches 0 (see FIG. 30 (b)).

Further, if the resistance pressure P ₁ ≈0, ΔP = P ₀ , but in the case of pressure infiltration into the ground, if the permeation resistance is large, ΔP becomes small and the ejection amount becomes small. However, if a sufficiently small FIG 30 (b) osmotic resistance pressure P _1, even if there is some change in the resistance pressure, ejection amount can be values by a nozzle bore diameter to obtain a constant value. In roads and residential land, injection should not cause ground displacement. For this reason, it must be injected at a small rate so as to penetrate between the soil particles (see FIG. 27).

  However, in this case, the construction efficiency is lowered, but since it is possible to inject with a large discharge amount as a whole by simultaneous injection from a plurality of injection locations, economic efficiency is obtained. Moreover, since it can construct without moving a construction plant if continuous injection is possible, it is excellent in efficiency, construction is completed in a short period of time, and great economic efficiency can be obtained. When the discharge speed is low or the water permeability of the ground is large, the resistance pressure is almost zero, and thus it is understood that a constant ejection amount corresponding to the pressurized liquid feeding pressure and the orifice diameter is obtained (FIG. 29 (b )reference). Therefore, as shown in FIG.31 (b), according to the water permeability of the ground at the injection point, the nozzle diameter, the number of nozzles and the number of injection points are plural, and a predetermined amount of injection liquid is injected at each injection point. Can be supplied at the same time.

  In the present invention, a regulator (manufactured by Kosaku Giken Co., Ltd.) can be used in addition to the orifice. The regulator can control the pressure and flow rate on the downstream side corresponding to the pressure on the upstream side, and it can be installed in multiple pipes to control the pressure and flow rate at the same time. Regarded as a variable pressure type orifice, it is handled as a kind of orifice.

  Of course, in the present invention, even if the orifice is not used, by operating the branch valve 5 by the controller 7, only the branch valve 5 can be operated to sequentially supply and inject the material to a predetermined injection location (FIG. (See 32 (a)).

In FIG. 26 (a), if the branch valve is operated without using an orifice, the branch valve V ₁ is opened and the others are closed, the processing liquid is injected only from the branch valve V ₁ , and the branch valve Vi is opened to When closed, the processing liquid is injected from the branch valve Vi, so that the processing liquid can be continuously and selectively injected. In addition, if an orifice is used, simultaneous injection into all injection parts becomes possible. The branch valve can be actuated by an electrical signal from the controller 7 using an electromagnetic valve.

  Also, the plurality of unit pumps 9 and branch valves shown in FIGS. 26 (b) and 36 can be collectively managed by the controller 7 to facilitate simultaneous supply or selective supply to a plurality of injection locations.

(I) The injection material used for the above injection system is a long liquid supply line, without being gelled in the injection line, without being gelled, and in order to be injected between soil particles at a low discharge speed, the gelation time However, a long gelation time of several tens of minutes to several tens of hours is required. Furthermore, it is necessary that the injection solution is durable over a long period of time.

  For that purpose, an injection material containing one or more kinds selected from silica solution (colloidal silica type grout, silica sol type grout, water glass type grout), clay, bubbles, cement and slag as an active ingredient alone or in combination. It is preferable to use an injection material excellent in durability that gels in a long time.

  On the other hand, there is a problem that an injection material having a long gelation time is deposited downward from the injection solution heavier than water to gelation after injection. For the purpose of the present invention, it is necessary to be able to form a small solid body at a predetermined position, unlike the case of ordinary injection work.

  For this reason, the gelation accelerator is injected first, or the injection tube is doubled or two in parallel, the gelation accelerator is injected from one side, and the injection solution having a long gelation time from the other side. May be injected together or injected into the main material by shortening the gel time.

  In this case, when the main material is acidic silica grout, as the accelerator, a slightly soluble alkali agent such as calcium carbonate or magnesium hydroxide may be used as in the experimental example, or water glass may be used. Good. Further, when the main material is water glass, a gelling time adjusting agent, cement or the like can be used as a gelling accelerator.

  Silica sol grout is an injection solution that neutralizes the alkali of water glass with acid to make the pH on the acidic side and gives long gelation time and durability. Colloidal silica is the alkali of water glass that is converted into an ion exchange resin or ion exchange membrane. This is a grout that is made from a silica colloid having a particle size of 5 to 20 nm, which is neutral to weakly alkaline and increased in size and stabilized by adding water glass or a reactive agent, and gelled for a predetermined time. Metal silica may be used as colloidal silica. Colloidal silica shows almost neutral value when the amount of acid used is zero or small, and does not cause corrosion in concrete and metal pipes in buried pipes, so it is not only a permanent grout, but also a non-polluting injection material from the environmental point of view. It is suitable for use in a living environment as in the present invention.

(J) The present invention is used in living areas such as roads and residential land. For this reason, removal of the injection tube may be required after the injection. In particular, injection pipes such as vinyl chloride are difficult to remove, and if they are left buried, they may hinder subsequent excavation work. For this reason, it is preferable to use an injection tube made of biodegradable resin.

  Since the construction in which the present invention is used is a place shallow from the ground surface, as the injection pipe that is easy to construct, the injection pipe may be a plastic thin tube having a diameter of 1 mm to 10 mm, or a plurality of thin tubes at different positions in the axial direction. In terms of workability, it is preferable from the viewpoint of workability to inject it into the ground using the injection tube that has been bundled. Furthermore, if an injection tube made of a biodegradable resin is used for these injection capillaries, it will be decomposed into carbon dioxide gas and water within half to one year after construction, and after construction in the living environment where the present invention is implemented. Even if it is left as it is, it becomes a liquefaction countermeasure work excellent in environmental conservation.

  The chemical structure of the biodegradable resin is (1) the main chain is aliphatic and has an ether bond or ester bond, and (2) the main chain (or side chain) has a hydroxyl group or a carboxyl group. Or (3) Plastics with good biodegradability by containing additives that induce and promote photodegradation and microbial degradation of plastics, specifically starch, cellulose acetate, Examples thereof include biodegradable plastics such as lactic acid series, aliphatic polyester series, and polyvinyl alcohol series. To these main raw materials, other polymer compounds such as plastics such as polyethylene and polypropylene, plasticizers, stabilizers, colorants and the like are added as necessary for the purpose of improving performance or imparting flexibility. You can also

  The compound (2) having a hydroxyl group or a carboxyl group is preferably an aliphatic compound. Specific examples of these biodegradable plastics include “Bionore” (aliphatic polyester of polyol and dicarboxylic acid) (Showa Polymer Co., Ltd. and Showa Denko Co., Ltd.), “Cell” Examples of “Green” (cellulose acetate, polycaprolactone) (Daicel Chemical Industries, Ltd.), “Lacty (lactic acid)” (Shimadzu Corporation), (2), “Poval” (polyvinyl alcohol) (Inc. Examples of (Kuraray) and (3) include “Wonder Starken” (corn starch and polyethylene) (Wonder Corporation) and the like.

  By blending the biodegradable plastics with high melting point biodegradable plastics such as polyhydroxybutyrate, polylactic acid, polyglycoside, etc., the processability is improved, and a woven fabric or non-woven fabric is used as a bag. Can also be used. These main raw materials are decomposed in the soil by bacteria for, for example, about 90 to 300 days. Further, the injection tube installation method of the present invention may be installed by driving a metal injection thin tube into the ground, or by driving a hollow tube with a cone into the ground and inserting the injection tube together with a seal grout, Any method may be used such as drawing out or, of course, installing an injection tube together with a seal grout in a bored hole.

1) In particular, gas pipes, water pipes laid in the ground that has non-liquefaction layers such as gravel layers and dense sand layers on the surface layer, or in the ground surface covered with asphalt pavement or concrete pavement, etc. It is possible to easily and economically suppress the floating accompanying the liquefaction of the existing buried pipe such as the sewer pipe and the rotation of the solidified body or the buried pipe which may occur along with the rising.

2) By forming a solid body around the line-shaped buried pipe in the extending direction, liquefaction can be prevented economically, safely and rapidly with a relatively small amount of injection solution. .

3) By selecting an effective injection amount and injection method, it is possible to sufficiently reduce the floating of the buried pipe.

4) By injecting so that the fluidity is maintained even when the injection is completed, the gelation time at the tip of the injection solution in the soil is allowed to flow down and solidify downward, and the buried tube in the consolidated body By solidifying in a shape that contains the material, a stable solidified body can be formed even during liquefaction, and the injection pipe drilling up to or near the side of the buried pipe is sufficient. Construction that does not occur can be performed.

5) When the surrounding ground is also liquefied, a certain floating reduction effect can be obtained by setting the safety factor to 0.7 or more.

6) When only the backfill portion is liquefied, it is important to fix the solidified soil mass on the non-liquefied ground.

7) By using a suitable injection method, a solid body that is integrated with the buried pipe at an interval along the buried pipe is formed with a small amount of injected chemical solution, so that it is efficient in terms of material construction instead of being economical. Not. It is possible to economically and efficiently construct a line-shaped buried pipe only after forming each solid body by the above-mentioned method with simultaneous injection or continuous injection of each solid body at intervals. .

DESCRIPTION OF SYMBOLS 1 Existing underground pipe 2 Injection pipe 3 Injection liquid production apparatus 4 Pressurized liquid feeding pump 5 Branch valve 6 Orifice 7 Controller 8 Vehicle 9 Unit pump
10 Ground displacement sensor
11 Asphalt pavement (non-liquefied layer or lining layer)
12 Consolidation
13 Support
14 Bearing plate

Claims (21)

  In the liquefaction countermeasure method for existing buried pipes laid in the ground that is liable to liquefy and has a non-liquefiable layer on the surface layer or a lining layer such as asphalt pavement or concrete pavement, A plurality of consolidated bodies are formed around the buried pipe and spaced apart in the tube axis direction of the buried pipe to give weight to the buried pipe, and the consolidated body is positioned above the buried pipe. A liquefaction countermeasure method for existing buried pipes, which is fixed to a non-liquefied layer or lining layer, and suppresses the rotation or displacement of the consolidated body accompanying liquefaction, thereby suppressing the floating of the buried pipe. .   The liquefaction countermeasure method for an existing buried pipe according to claim 1, wherein the consolidated body injects an injection material into the ground from a plurality of injection pipes installed at intervals in the tube axis direction of the buried pipe, An existing buried pipe liquefaction countermeasure method characterized in that it is formed integrally with the buried pipe at an interval in the tube axis direction of the buried pipe by infiltrating the pipe around the buried pipe.   In the liquefaction countermeasure method for existing buried pipes laid in the ground that is liable to liquefy and has a non-liquefiable layer on the surface layer or a lining layer such as asphalt pavement or concrete pavement, In addition to providing a weight to the buried pipe by forming a plurality of consolidated bodies integrally with the buried pipe and at intervals in the tube axis direction of the buried pipe, the consolidated body and the non-liquefied layer or lining are provided. A support is formed so as to support the buried pipe downward with respect to the layer, the support is fixed to the non-liquefaction layer or the lining layer, and the number and interval of the support and the solidity are fixed. A liquefaction countermeasure method for an existing buried pipe, wherein the weight and interval of the tied body are set so as to suppress the rotation or displacement of the solidified body accompanying liquefaction, thereby suppressing the floating of the buried pipe.   The liquefaction countermeasure method for an existing buried pipe according to claim 3, wherein the support is placed in an injection pipe installed to form a consolidated body around the existing buried pipe or in the ground after the injection pipe is pulled out. A liquefaction countermeasure method for existing buried pipes, characterized by inserting rod-shaped members.   5. The liquefaction countermeasure method for an existing buried pipe according to claim 3 or 4, wherein the support is injected with an injection material so that a solidified body formed around the existing buried pipe is fixed to the non-liquefied layer or the lining layer. A liquefaction countermeasure method for existing buried pipes, characterized by   The liquefaction countermeasure method for an existing buried pipe according to any one of claims 3 to 5, wherein a plurality of supports are formed at intervals in a direction perpendicular to the pipe axis of the buried pipe. Chemical countermeasure construction method.   In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 3 to 6, an injection material is injected into the ground from a plurality of injection pipes arranged at intervals in the pipe axis direction of the buried pipe, A liquefaction countermeasure method for an existing buried pipe characterized in that a pouring material is allowed to flow down and permeate into one or a plurality of locations at the top, side or bottom of the buried pipe to form a consolidated body integral with the buried pipe and the support.   The liquefaction countermeasure method for an existing buried pipe according to claims 2 to 7, wherein the gelation time in the soil is made longer than the injection time of the injection material, or the gelation time of the penetration tip portion of the tip portion of the injection material The liquefaction is integrated with the buried pipe by instilling the injected material into one or more places at the top, side or bottom of the buried pipe by injecting so that the fluidity is maintained even when the injection is completed. A liquefaction countermeasure method for existing buried pipes, characterized in that it forms a consolidated body with a stable shape sometimes. In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 8, a plurality of injection pipes are installed at predetermined intervals in the extending direction of the buried pipe, and the following (1), (2) , (3) to inject the injection material from the injection pipe to the periphery of the buried pipe and integrate the buried pipe and the consolidated body in the backfilled soil to suppress the rising due to the earthquake The injection material is injected and the safety factor F = (gravity on the tube and consolidated soil) / (buoyancy on the tube and consolidated soil) is set, The amount of consolidation and the interval between the consolidated bodies are set, and the safety factor F is set as follows (b) and (b) to suppress the floating, and the liquid of the existing buried pipe is characterized by Chemical countermeasure construction method.
(1) A method in which the buried pipe is fixed to the non-liquefied layer of the original ground to prevent the existing buried pipe from rising during an earthquake.
(2) A method to solidify the backfill soil under the buried pipe and prevent the buried pipe from rising due to the soil in the non-liquefied layer falling to the left and right or the top during an earthquake.
(3) A method of suppressing the floating by solidifying the upper surface or the side surface of the buried pipe, integrating the buried pipe and the consolidated body, and increasing the gravity applied to the buried pipe and the consolidated body.
(I) When the surrounding ground is liquefied,
Safety factor F ≧ 0.7
(B) When only the backfill part is liquefied,
(I) When consolidating the upper part of the buried pipe,
Safety factor F ≧ 0.7
(Ii) In the case where the buried pipe and the consolidated portion are fixed to the side surface portion and / or the bottom surface portion of the non-liquefied layer,
Safety factor F ≧ 0.6 10. The liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 9, wherein F is set as follows.
F (safety factor) = (AVpipe + BVsolidified) / (CVpipe + CVsolidified)
= (A + B (Vsolidified / Vpipe)) / (C + C (Vsolidified / Vpipe))
However, A: density of buried pipe, B: density of consolidated soil, C: density of mud during liquefaction, volume of pipe: Vpipe, volume of solidified soil: Vsolidified In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 10,
The consolidated body is formed at a predetermined interval, and the formed body is formed by any one of the following methods (1), (2), and (3): Liquefaction countermeasure construction method.
(1) A method of injecting from the injection pipes provided on both sides of the buried pipe and fixing the buried pipe to the non-liquefied layer of the original ground.
(2) A method of injecting from one side of the buried pipe and consolidating the backfill soil at the bottom of the buried pipe to integrate the buried pipe and the consolidated body.
(3) A method of injecting into the upper part of the buried pipe and integrating the buried pipe and the consolidated body to increase the gravity applied to the buried pipe and the consolidated body.   In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 11, the amount of consolidation in the extension direction of the buried pipe and the interval between the consolidated bodies are determined so that the safety factor F ≧ 0.7 or more. A liquefaction countermeasure method for existing buried pipes.   In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 12, a predetermined construction is provided along a laying structure laid in a line, an injection line laid in a line, or a peripheral part of a structure. A plurality of injection pipes are arranged at intervals, and the injection pipes are connected to a liquid feed pipe via a flow path conversion valve. The liquid feed pipe is an injection pump equipped with a pressure / flow meter and an injection material storage tank. And liquefying the existing buried pipe by injecting the flow path to the injection pipe continuously or selectively by operating the flow path conversion valve.   14. The liquefaction countermeasure method for an existing buried pipe according to claim 13, wherein the flow path conversion valve and the injection pump are collectively controlled by a controller based on information from the pressure flow meter, thereby switching injection at a plurality of injection points. The liquefaction countermeasure method for existing buried pipes, characterized by   The liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 14, wherein the injection pipe is connected to a liquid feeding pipe through an orifice, and the liquid feeding pipe is provided with a pressure / flow meter. A liquefaction countermeasure method for existing buried pipes, which is equipped with a pump and an injection material manufacturing apparatus and is injected simultaneously or selectively into a plurality of injection pipes.   In the liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 13, a predetermined construction is provided along a laying structure laid in a line, an injection line laid in a line, or a peripheral part of a structure. A plurality of infusion pipes are arranged at intervals of each other, and the infusion is communicated from a plurality of unit pumps to a plurality of infusion lines, respectively, and the operation of each unit pump is determined from the pressure flow measurement of the plurality of unit pumps. A liquefaction countermeasure method for existing underground pipes, which is managed by a controller based on information.   The liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 16, wherein the injection pipe is a plastic thin tube having a diameter of 1 mm to 10 mm.   The liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 17, wherein the injection pipe is injected into the ground using an injection pipe formed by binding a plurality of the injection pipes at different positions in the axial direction. A liquefaction countermeasure method for existing buried pipes.   The liquefaction countermeasure method according to any one of claims 1 to 18, wherein a ground displacement measuring device is arranged at an arbitrary point, and injection is controlled based on a measurement value by the ground displacement measuring device. Liquefaction countermeasure method for existing buried pipes.   In the liquefaction countermeasure construction method according to any one of claims 1 to 19, an injection material containing one or more kinds selected from silica solution, clay, bubbles, gas, cement, and slag as an active ingredient alone or A liquefaction countermeasure method for existing buried pipes, which is injected in combination.   21. The liquefaction countermeasure method for an existing buried pipe according to any one of claims 1 to 20, wherein the injection pipe is formed of a biodegradable resin.

Images