JP2010101025A - Construction method and construction apparatus for diaphragm wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method and a construction apparatus for a diaphragm wall, improving workability and reducing environmental load. <P>SOLUTION: A chain-type cutter 32 is rotated in the state of being built up in the ground, and the cutter 32 is moved to continuously excavate a ditch G of constant width. A PC wall body is then inserted in the ditch G to form the diaphragm wall. Muddy water W produced in the excavation is recovered, and a sediment part D is separated from the recovered muddy water W. The separated sediment part D and classified muddy water W1 which is a separated liquid separated from the sediment part D are recycled. When the PC wall body of large cross section is used, a large quantity of waste is generated, but the muddy water W produced by the excavation is recovered and separated into the separated liquid and a sediment part D. The muddy water W heretofore required to be discarded or treated can thereby be effectively utilized. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an underground continuous wall construction method and construction apparatus constructed in civil engineering construction.

  To improve the workability of the underground continuous wall, a chain type cutter, in which an endless chain equipped with a drilling blade is stretched between a drive wheel and a guide wheel provided on the cutter post, is attached to the guide. While the chain cutter is inserted into the ground, it is horizontally moved by the guide while rotating the cutter to excavate the continuous wall into the ground, and the solidified material is injected into the excavated continuous groove. There is a known construction method (for example, Patent Document 1) for creating a continuous wall in the ground.

  In the above construction method, while excavating with a cutter, the excavated sediment is mixed with the excavated liquid in the excavated hole and preceded excavation is performed, and the solidified material injected with the excavated sediment in the excavated hole is solidified in the subsequent solidification stage. In order to construct a continuous wall by mixing, in principle, muddy water is generated for the injected drilling fluid and solidified material. For this reason, conventionally, a mud pit is provided at the site, solidified by performing sun drying or cement solidification, and then carried out, or after reaching a predetermined strength, reused at the site.

In addition, there is a known method for constructing a continuous underground wall in which a wall forming pillar is continuously installed in a drilling groove in which a slurry containing a solidifying material is formed to form a leading wall. After the temporary pillar material is installed in close contact and the slurry is solidified to form a soil cement, the temporary pillar material is pulled out to form a connecting gap on the joint surface of the preceding wall, and the slurry containing the solidified liquid And then drilling back to the connecting gap and excavating the excavation groove for the subsequent wall, and then installing the wall forming column material for the subsequent wall in close contact with the joining surface of the preceding wall (for example, Patent Document 2).
JP-A-7-180154 JP 2006-70608 A

  In the construction method of the underground continuous wall, when installing a wall-forming column with a large cross section in the excavation groove, the volume of the wall-forming column to be used is larger than the wall thickness of the underground wall. A large amount of mud is discharged, and this mud is disposed of as industrial waste. However, since the amount of disposal is large, there is a problem that the treatment cost becomes enormous.

  Moreover, in the construction method of the underground continuous wall, the leading wall and the wall forming pillar material for the trailing wall can be brought into close contact with each other, but work for installing and removing the temporary pillar material on the leading wall is required. At the same time, it was necessary to return to the preceding wall that became the soil cement and excavate the soil cement portion again.

  Therefore, the present invention eliminates waste by reusing the muddy water generated when building the underground continuous wall, improves workability, and reduces the environmental load. An object is to provide a construction method and a construction apparatus, and in addition, it is not necessary to install and remove a temporary pillar material, and it is not necessary to re-excavate a soil cement portion, thereby improving workability.

  According to the first aspect of the present invention, in the state where the chain type cutter is built in the ground, the cutter is rotated, and the cutter is moved to continuously excavate a groove having a constant width, and a wall is formed in the groove. In the construction method of the underground continuous wall in which the pillar material is inserted to form the underground wall, the wall forming pillar material is a PC wall body, and the muddy water generated during the excavation is recovered, and the recovered muddy water is In this construction method, the earth and sand are separated, and the separated earth and sand and the separated liquid from which the earth and sand are separated are reused.

  Invention of Claim 2 is the construction method which fills the said solidification material in the said groove | channel after inserting the said PC wall body in the said groove | channel.

  According to a third aspect of the present invention, the solidifying material is injected into the excavated soil in the groove while moving the cutter, and the PC wall is inserted into the groove into which the solidifying material has been injected to form an underground wall. Is the method.

  Invention of Claim 4 is the construction method which attracts | sucks the said generated muddy water with a squeeze pump.

  Invention of Claim 5 is the construction apparatus used for the construction method of the underground continuous wall of Claim 1, The squeeze pump which collect | recovers the generated muddy water, A mud storage tank which stores the muddy water collect | recovered with this squeeze pump, The construction apparatus includes a soil and sand separation means for separating the soil and sand from the mud in the mud tank.

  According to the configuration of claim 1, when a PC wall having a large cross section is used, a large amount of waste is generated. However, in order to collect muddy water generated by excavation and separate it into a separated liquid and sediment, Muddy water that needs to be disposed or treated can be used effectively. For example, the separation liquid contains components of drilling liquid and fine particles such as silt and clay generated on site, so it can be reused in the separation liquid. The amount of additive components used can be reduced, and earth and sand can be reused for civil engineering materials.

  Further, according to the configuration of claim 2, since the solidified material is filled after the PC wall is inserted, the workability is improved by filling the solidified material in the jointed portion after constructing the pouring portion. can do. That is, it becomes unnecessary to install and remove the conventional temporary pillar material and to re-excavate the soil cement portion.

  Moreover, according to the structure of Claim 3, the muddy water containing the solidification material is collect | recovered, and it can isolate | separate into a separated liquid and earth and sand, and can reuse earth and sand or separated water.

  Moreover, according to the structure of Claim 4, even if the generation amount of muddy water increases, muddy water can be sucked smoothly and continuously.

  Further, according to the configuration of claim 5, by constructing the underground wall using this device, the muddy water generated at the time of excavation, at the time of insertion of the PC wall body 2 or at the injection of the solidified material is recovered, Muddy water that needs to be discarded or treated can be used effectively. Further, when the PC wall is inserted, the amount of mud generated increases, and even if the processing capacity of the apparatus is exceeded, it can be stocked once in the mud storage tank and processed.

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all the configurations described below are not necessarily essential requirements of the present invention. In each example, by adopting a new underground continuous wall construction method and construction equipment different from conventional ones, an underground continuous wall construction method and construction equipment with an unprecedented function can be obtained. The construction method and construction equipment for the medium continuous wall are described respectively.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 5 show a first embodiment of the present invention. As shown in FIG. 1, the underground continuous wall 1 is constructed by a plurality of PC wall bodies (precast concrete wall bodies) 2. 2, the plane section has a substantially square shape, a substantially circular hollow portion 3 connected in the longitudinal direction is formed at the center thereof to form a cylindrical shape, and the joining surface 4 on which adjacent PC wall bodies 2 and 2 are in contact with each other. A plurality of joining grooves 5 and 5 are formed.

  11 is the ground, 12 is a self-propelled vehicle of the excavator 10, 13 is a crawler, 14 is a swivel, 15 is a driver's cab, and 16 is a hydraulic unit provided at the rear. In the present embodiment, the upper horizontal member 17, the lower horizontal member 18, and the four vertical members 19 are framed to form a frame 20, and the frame 20 is fixed vertically on one side of the vehicle 12. . That is, 21 is two brackets projecting on the outer surface of one of the crawlers 13. The lower horizontal member 18 of the frame 20 is fixed to the bracket 21 and the bracket is projected on the rear surface of the upper horizontal member 17 of the frame 20. The frame 20 is fixed by connecting the rear end of the stay 23 connected to 22 to a bracket 24 protruding outside the other crawler 13.

  Further, the excavator 10 is provided with a vertical frame 25 slidable in the horizontal direction with the horizontal members 17 and 18 above and below the frame 20 as guides. A bracket portion 25a is slidably engaged with the guide portion of the upper horizontal member 17, and a bracket portion 25b is slidably engaged with the guide portion of the lower horizontal member 18. Further, the base portion of the hydraulic cylinder 26 is pivotally supported on the upper horizontal member 17, and the tip end portion of the piston rod 26 a is connected to the upper portion of the vertical frame 25 via the connecting member 27, and the base portion of the hydraulic cylinder 28 is connected to the lower horizontal member 18. And the tip of the piston rod 28a is connected to the lower portion of the vertical frame 25 via a connecting member 29.

  Further, the excavator 10 is provided with a cutter support post 30 that can be raised and lowered with respect to the vertical frame 25. 31 (see FIG. 4) is a hydraulic cylinder for raising and lowering. An endless chain cutter 32 is provided perpendicular to the cutter support post 30. 33 is a cutter post of this cutter 32, which is composed of a box frame that is long vertically, 34 is a sprocket provided at the upper end of the cutter post 33, 35 is a sprocket provided at the lower end of the post 33, and 36 is the upper and lower This is an endless chain with excavating blades that spans sprockets 34 and 35. 37 is a motor for driving the cutter, and 38 is a transmission device. In the figure, 51 is an injection device for injecting a drilling fluid A and a solidified material K such as cement liquid (cement slurry) or grout material into the excavated groove G. This injection device 51 is provided in the excavation device 10 and includes the cutter The drilling fluid A and the solidified material K such as cement liquid (cement slurry) grout material are selectively injected into the groove G from the lower end side of 32.

  As shown in FIGS. 4 to 6, the construction apparatus includes a mud tank 71 to which the muddy water W generated from the site is sent and the muddy water W together with the excavator 10 provided in the self-propelled vehicle 12 described above. Vibrating sieve 72 as a means for separating soil and sand D, mud adjustment tank 73 to which classification mud W1 separated from the mud W is sent, and water is supplied into the mud adjustment tank 73 In the fresh water tank 74, the automatic measuring device 75 for detecting the concentration of the adjusted mud water W2 obtained by mixing the classified mud water W1 sent to the mud water adjustment tank 73 and the water in the fresh water tank 74, and the sewage adjustment tank 73 And an infusion solution supply device 76 to which the adjusted adjusted sewage W2 is sent.

  First, at the time of excavation, as shown in FIG. 3A, the cutter 32 is suspended and inserted into the excavation hole 61 on the start end side of the underground wall construction position, and the cutter 32 is attached to the vertical frame 25. . Next, in a state where the hydraulic cylinders 26 and 28 are contracted, the guide direction by the upper and lower horizontal members 17 and 18 of the frame 20 is made to coincide with the direction of the underground continuous wall 1 to be constructed, and if necessary, the crawler 13 Is fixed to the ground 11 by an anchor or the like so as not to move, and in this state, while driving the chain 36 of the cutter 32 by the motor 37, pressure oil is supplied to the hydraulic cylinders 26 and 28, and each piston rod 16a, By extruding 18a, the cutter 32 is moved through the vertical frame 25 while digging so as to loosen the ground 11 in the direction of the arrow in FIG. At this time, the drilling liquid A is injected from the injection device 51 into the traveling direction or the excavated groove G, and the excavating liquid A and the earth and sand in the groove G are agitated. The drilling fluid A is mainly a mixture of bentonite and water. By using the drilling fluid A, the inside of the groove G is stabilized and the cutter 32 is driven smoothly. It becomes easy to loosen and excavation becomes easy.

  When the piston rods 26a, 28a of the hydraulic cylinders 26, 28 are fully extended, the piston rods 26a, 28a are retracted, and the self-propelled vehicle 12 is moved to the right as shown in FIG. It moves to a direction (excavation direction), repeats the above-mentioned operation again, and excavates so that the groove | channel G for underground walls of predetermined length may be loosened. Further, the drilling fluid A is injected from the injection device 51 into the traveling direction or the excavated groove G, and the drilling fluid A and a part of the earth and sand in the groove G are stirred. In this case, the cutter 32 can be returned to the left side in the figure to stir the groove G.

  Subsequently, as shown in FIG. 3B, the PC wall 2 is continuously inserted into the groove G containing the mixture of the drilling fluid A and the earth and sand, and the ground having a predetermined length L from the start position is inserted. The middle continuous wall 1 is formed. The predetermined length L is a length that can be applied in a day's process, but is a length that can be appropriately set according to the process. On the other hand, after inserting the PC wall 2, the solidified material K is filled into the groove G having a solidification range length shorter than the predetermined length L from the start position, and the non-filling range Lh at the construction completion position which is the anti-start position. Is not filled with the solidifying material K. For the filling, a solidification material filling device 62 is used, and a solidification material such as a grout material is added to the mixture between the inner wall GN of the groove G and the PC wall body 2 and between the hollow portion 3 and the joining grooves 5 and 5. Fill with K. Since the non-filling range Lh straddles the construction completion position in the middle of one process and the non-filling range Lh is not filled with the solidifying material K, the mixture of the grooves G in this range does not solidify, and the predetermined length L After the construction is completed, for example, the PC wall 2 can be inserted into the groove G continuously on the next day or in the next process. Note that the excavator 10 is retracted from the midway construction completion position to the preceding excavation excavator 63, but the retracted excavator 63 can be shortened. Further, in the next step, the excavator 10 is moved backward from the evacuation excavating part 63 to the construction completion position to loosen the earth and sand in the groove G, and then the PC wall 2 is inserted into the groove G. In this case as well, the back excavation is shorter than in the conventional case.

  On the next day or in the next process, if necessary, the excavator 10 is returned to the construction completion position while injecting the drilling fluid A, and the excavator 10 is excavated by stirring the earth and sand in the groove G. Move in the direction, perform excavation of a predetermined length L as described above, and after inserting the PC wall 2, except for the non-filling range Lh at the midway construction completion position, the solidified material K is filled, Prepare for the next day or the next step.

  The excavator 10 provided with the endless chain cutter 32 has high construction accuracy and can ensure continuity. Therefore, the distance between the PC wall 2 and the inner wall GN of the groove G is about several centimeters (10 cm or less) on one side. As a result, the injection amount of the solidifying material K can be greatly reduced.

  At the time of excavation in which the drilling fluid A is injected as described above, as shown in FIG. 1, the mud water W generated from the site at the time of construction is sent by the squeeze pump 70 to the mud tank 78 through the pipe line 71A. The muddy water W stored in the muddy tank 78 is sent to the muddy water tank 71, and water is added to the muddy water W in the muddy water tank 71 as necessary to adjust the water content ratio. In this case, the water content ratio of the muddy water W is set to 75 to 125% in order to facilitate selection in the vibrating sieve 72. The water content is the ratio of solids such as soil particles to water (water content = water weight / solid weight × 100). The solid content includes bentonite contained in the drilling fluid A in addition to earth and sand, Including silt and clay generated from. The muddy water W whose water content ratio is adjusted in the muddy water tank 71 is sieved into the earth and sand content D and the classified muddy water W1 in the vibrating sieve 72. For example, the mesh of the vibrating sieve 72 is about 1 mm mesh, and the soil particles passing through the mesh of this size are included in the classified mud water W1, for example, the classified mud water W1 having a water content ratio of 105 to 155%. The obtained and sieved soil and sand content D has a water content ratio of 20 to 40%, and this soil and sand content D is used as a civil engineering material inside or outside the construction site. On the other hand, the classified mud water W1 containing fine particles such as bentonite, silt and clay generated from the site is sent to the muddy water adjustment tank 73 through the pipe 73A, and the water in the fresh water tank 74 passes through the pipe 74A. The concentration, specific gravity, viscosity, etc. of the adjusted mud water W2 mixed with the water sent from the fresh water tank 74 and the classified mud water W1 are measured by the automatic measuring device 75 and adjusted mud water W2. Is sent to the injection liquid production apparatus 76 through the pipe line 76A, and the drilling liquid A is produced by additionally mixing bentonite. The drilling liquid A is sent to the injection apparatus 51 through the pipe line 76B. The muddy water adjusting tank 73 is provided with stirring means 77 such as a rotary stirring blade or a jet stirring apparatus, and the adjusted muddy water W2 is uniformly stirred by the stirring means 77.

  Since the PC wall 2 has a larger cross section than H-shaped steel or the like, a large amount of muddy water W is generated when inserted into the groove G. By continuously sucking the muddy water W by the squeeze pump 70, a large amount of mud W can be sucked. Further, before sending the mud W sucked from the groove G to the mud tank 71, a mud tank 78 for storing the mud water W collected by the squeeze pump 70 is provided, and the mud tank 78 is provided in the middle of the pipe 71A. Is provided. The mud storage tank 78 is provided with a stirring device 79 for stirring the mud W.

  Therefore, even if mud W exceeding the processing capability such as the vibrating screen 72 of the processing device is generated, the mud W can be efficiently processed without increasing the size of the processing device by stocking in the mud storage tank 78. it can.

  The moisture content (moisture content ratio) of the mud water W generated by the insertion and excavation of the PC wall 2 is adjusted, and the sand content D of 1 mm or more is sieved and separated from the classified mud water W1, and the separated soil content D Since the classified mud water W1 contains bentonite, fine particles such as silt and clay generated from the site, by reusing the classified mud water W1 to the drilling fluid A, The amount of bentonite to be added can be reduced.

  Further, the construction apparatus is provided with a filter press 81 as a dehydrating means for filtering and dewatering the classified mud water W1 with a press, if necessary. As shown in the schematic diagram of FIG. 1, the filter press 80 includes a plurality of filter plates 83 each having a plurality of filter cloths arranged between a fixed frame 81 and a clamping plate 82. A filter chamber is formed between 83 and 83, the clamping plate 82 is moved by a hydraulic cylinder (not shown), and the classified muddy water W1 in the filter chamber is pressed and filtered by a pump pressure for supplying muddy water into the filter chamber. Dehydrated earth and sand Dd and filtered water are obtained. The dehydrated earth and sand Dd is used as a civil engineering material inside or outside the construction site, and the filtered water passes through the pipe 80B to the fresh water tank. 74 and further sent from the fresh water tank 74 to the muddy water adjustment tank 73.

  And when there is a high necessity for soil and sand D as a civil engineering material to be used in the field, the classified muddy water W1 is sent to the filter press 81 through a pipe line 80A connecting the vibrating sieve 72 and the filter press 81, for example, containing water A dehydrated earth and sand portion Dd having a ratio of 20 to 40% can be obtained and reused as a civil engineering material.

  Therefore, in the above method, classification can be performed using a construction machine conventionally used in civil engineering work without using a complicated sorting device, and the classified mud water W1 is made of silt, clay, bentonite. Since the fine particle content is contained, the amount of bentonite used can be reduced by mixing the classified mud water W1 into the drilling fluid A. Moreover, the supply amount of the classified sediment component Dd can be adjusted by mechanically dewatering the classified mud water W by the press dewatering means. Moreover, the generation of industrial waste can be eliminated by controlling the construction waste soil.

  In particular, it is effective when there are few fine grains (10% or less) in the ground at the excavation site, and where there is a lot of gravel and sand, a lot of bentonite is required to ensure the stability of the groove wall. At this time, since the amount of bentonite used can be reduced by mixing the classified mud water W1 containing fine particles into the drilling fluid A, the construction is economical.

  Therefore, in the above method, classification can be performed using a construction machine conventionally used in civil engineering work without using a complicated sorting device, and the classification mud water W1 in the solidification stage is used as the solidification material K. By doing so, the amount of cement used can be reduced by the cement contained in the muddy water W generated on site. Moreover, the supply amount of the classified sediment component Dd can be adjusted by mechanically dewatering the classified mud water W by the press dewatering means. Moreover, the generation of industrial waste can be eliminated by controlling the construction waste soil.

  Thus, in the present embodiment, corresponding to claim 1, the cutter 32 is rotated and the cutter 32 is moved in a state where the chain type cutter 32 is built in the ground, so that a groove G having a constant width is obtained. In the construction method of the underground continuous wall in which the wall forming pillar material is inserted into the groove G to form the underground wall 1, the wall forming pillar material is the PC wall body 2. Since the mud water W generated at the time of excavation is collected, the earth and sand part D is separated from the collected mud water W, and the separated earth and sand part D and the classification mud water W1 which is the separated liquid separated from the earth and sand part D are reused. If the PC wall body 2 having a large cross section is used, a large amount of waste is generated. However, in order to collect the muddy water W generated by excavation and separate it into the separated liquid and the sediment D, conventionally, disposal or treatment is required. Muddy water W can be used effectively. And fine particles such as silt and clay that are generated on site, it can be reused in the separation liquid, and the amount of additive components used can be reduced. Can be reused.

  In this way, in this embodiment, after inserting the PC wall body 2 into the groove G and filling the solidified material K into the groove G in accordance with claim 2, after constructing the pouring portion, By filling the joint portion with the solidifying material K, the workability can be improved. That is, it becomes unnecessary to install and remove the conventional temporary pillar material and to re-excavate the soil cement portion.

  In this way, in this embodiment, the generated muddy water W is sucked by the squeeze pump 70 in correspondence with the fourth aspect. Therefore, the muddy water W is sucked smoothly and continuously even if the amount of muddy water generated is increased. be able to.

  In this way, in this embodiment, corresponding to claim 5, in the construction apparatus used for the construction method of the underground continuous wall according to claim 1, the squeeze pump 70 for collecting the generated muddy water W, and the squeeze A mud storage tank 71 for storing the mud water W collected by the pump 70, and a vibrating sieve 72 as a soil sediment separating means for separating the soil sediment D from the mud water W of the mud tank 71 are provided. By constructing the inner wall 1, the muddy water W generated at the time of excavation, the insertion of the PC wall 2 or the injection of the solidified material can be recovered, and the muddy water W conventionally required to be discarded or treated can be effectively used. . Further, when the PC wall 2 is inserted, the amount of generated muddy water W increases, and even if the processing capacity of the apparatus is exceeded, the mud storage tank 71 can be stocked and processed.

  Further, as an effect on the embodiment, the earth and sand separation means is the vibrating sieve 72, and is a dewatering means for dewatering the earth and sand D remaining in the classified mud water W1 as a separation liquid obtained by separating the earth and sand D by the vibration sieve by a press. Since the filter press 81 is provided, the earth and sand D can be separated by the vibrating sieve 72, and further the earth and sand Dd can be separated by the filter press 81 and reused as a civil engineering material without providing a dedicated separation facility. it can. Further, the mud water W generated in the solidification stage is recovered, the earth and sand part D is separated from the recovered mud water W, and the separated mud water W1 and the earth and sand part D which are separated liquids separated from the separated earth and sand part D and the earth and sand part D Therefore, the muddy water W that has been conventionally required to be discarded or treated can be effectively used. For example, the classified muddy water W1 is a cement component, a component of the drilling fluid A, and a silt or clay component generated from the site. As a result, the cement component can be reused and the amount of cement used can be reduced. The filter press 81 is a press dewatering means for dewatering the earth and sand D remaining in the classified mud water W1 by a press, and by using this, the dewatering can be performed efficiently.

  Further, as an effect on the embodiment, the PC wall body 2 has a substantially square cross section and a large cross sectional area. However, since the PC wall body 2 has the hollow portion 3, the inside of the groove G in which the earth and sand and the drilling fluid A are mixed is provided. Easy to insert into. Further, since the joining groove 5 is located between the adjacent PC wall bodies 2, 2, by injecting the solidifying material K into the mixture of the earth and sand and the drilling fluid A in the joining groove 5, Matching PC wall bodies 2 and 2 can be integrated.

  FIG. 7 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. This example includes a solidification stage process using the solidification material K and a drilling process using the drilling fluid A in construction.

  First, in the solidification stage in which the solidification material K is injected to build the underground continuous wall 1, similarly, as shown in FIG. 7 (A), the cutter 32 is inserted into the excavation hole 61 on the start end side of the underground wall construction position. The cutter 32 is attached to the vertical frame 25 while being suspended and inserted. Next, in a state where the hydraulic cylinders 26 and 28 are contracted, the guide direction by the upper and lower horizontal members 17 and 18 of the frame 20 is made to coincide with the direction of the underground continuous wall 1 to be constructed, and if necessary, the crawler 13 Is fixed to the ground 11 by an anchor or the like so as not to move, and in this state, while the chain 36 of the cutter 32 is driven by the motor 37, pressure oil is supplied to the hydraulic cylinders 26 and 28, and each piston rod 16a, By extruding 18a, the cutter 32 is moved through the vertical frame 25 while excavating the ground 1 in the direction of the arrow in FIG. At this time, the solidification material K is injected from the injection device 51 into the groove G in the traveling direction or excavated, and the solidification material K and the earth and sand in the groove G are agitated. As the solidifying material K, cement slurry is used.

  When the piston rods 26a, 28a of the hydraulic cylinders 26, 28 are fully extended, the piston rods 26a, 28a are retracted, and the self-propelled vehicle 12 is moved to the right as shown in FIG. 7B. Then, the above-mentioned operation is repeated again to excavate the underground wall groove G having a predetermined length. Further, the solidification material K is injected from the injection device 51 into the traveling direction or the excavated groove G, and the solidification material K and a part of the earth and sand in the excavation hole 61 are stirred. In this case, the cutter 32 can be returned to the left side in the figure to stir the groove G.

  Next, the PC wall 2 is continuously inserted into the groove G containing the mixture of the solidifying material K and the earth and sand, and the underground continuous wall 1 having a predetermined length L from the start position is formed. The predetermined length L is a length that can be applied in a day's process, but is a length that can be appropriately set according to the process. And temporary material (not shown) is arrange | positioned in the joining surface 4 of the midway construction completion position of the continuous underground wall 1. Note that the excavator 10 is retracted from the intermediate excavation completion position to the preceding excavation excavator 63.

  On the next day or the next process, the temporary material is pulled out, and as shown by the white arrow in FIG. After the earth and sand in the groove G is stirred and returned, the excavator 10 is moved in the excavation direction as shown in FIG. The above excavation is performed, the PC wall 2 is inserted into the groove G by a predetermined length L, and the same process is repeated.

  In the solidification step in which the solidification material K is injected and the PC wall 2 is inserted in this way, the apparatus shown in FIG. 1 is used, and as shown in FIG. The squeeze pump 70 is sent to the mud tank 78 through the pipe 71A and the mud water W stored in the mud tank 78 is sent to the mud tank 71 through the pipe 71A, and water is supplied to the mud water W of the mud tank 71 as necessary. To adjust the water content. In this case, the water content ratio of the muddy water W is set to 75 to 125% in order to facilitate selection in the vibrating sieve 72. The moisture content is the ratio of solids such as soil particles to moisture (moisture content = moisture weight / solids weight × 100). The solid content includes cement contained in the solidified material K in addition to earth and sand, excavation It contains bentonite contained in liquid A, silt and clay generated from the site. The muddy water W whose water content ratio is adjusted in the muddy water tank 71 is sieved into the earth and sand content D and the classified muddy water W1 in the vibrating sieve 72. For example, the mesh of the vibrating sieve 72 is about 1 mm mesh, and the soil particles passing through the sieve of this size are included in the classified mud water W1, for example, the classified mud water W1 having a water content ratio of 85 to 135%. The obtained and sieved soil and sand content D has a water content ratio of 28 to 48%, and this soil and sand content D is used as a civil engineering material inside or outside the construction site. On the other hand, the classified mud water W1 containing fine particles such as cement, bentonite, silt and clay generated from the site is sent to the mud adjustment tank 73 through the pipe 73A, and the water in the fresh water tank 74 is sent to the pipe. The concentration, specific gravity, viscosity, etc. of the adjusted mud water W2 mixed with the water sent from the fresh water tank 74 and the classified mud water W1 are measured by the automatic measuring device 75 and adjusted. The muddy water W2 is sent to the injection liquid production apparatus 76 through the pipe line 76A, and the cement is additionally mixed to produce a solidified material K such as cement slurry, and the solidification material K passes through the pipe line 76B and the injection apparatus. Sent to 51.

  In this way, the water content (moisture content ratio) of the mud water W generated by the solidification stage is adjusted, and the sand and sand content D of 1 mm or more is sieved and separated from the classified mud water W1, and the separated soil and sand content D is used as a civil engineering material. In addition, since the classified mud water W1 contains fine particles such as cement, bentonite, silt and clay generated from the site, it can be added by reusing the classified mud water W1 to the solidifying material K, etc. The amount of cement used can be reduced.

  In addition, the construction apparatus is provided with a filter press 81 as a dewatering means for filtering and dewatering the classified mud water W1 with a press, if necessary. Dd and filtered water are obtained, and the dehydrated earth and sand Dd is used as a civil engineering material inside or outside the construction site, and the filtered water is sent to the fresh water tank 74 through the pipe line 80B. To the muddy water adjustment tank 73.

  And when there is a high necessity for soil and sand D as a civil engineering material to be used in the field, the classified muddy water W1 is sent to the filter press 81 through a pipe line 80A connecting the vibrating sieve 72 and the filter press 81, for example, containing water A dehydrated earth and sand part Dd having a ratio of 30 to 50% is obtained.

  Further, during the backward excavation, the excavating liquid A is injected from the injection device 51 into the traveling direction or the excavated groove G, and the excavating liquid A and the earth and sand in the groove G are agitated. The drilling fluid A is mainly a mixture of bentonite and water. By using the drilling fluid A, the inside of the groove G is stabilized and the cutter 32 is driven smoothly. It becomes easy to loosen, and back excavation becomes easy.

  As shown in FIG. 1, the mud water W generated from the site during construction is sent to the mud tank 71 through the pipe 71A by the squeeze pump 70 as shown in FIG. The water content is adjusted by adding water to the muddy water W in the muddy water tank 71 (hydrolysis), the muddy soil W is treated in the same manner as in the solidification step, and the separated earth and sand D can be used as a civil engineering material. Since the classified mud water W1 contains bentonite and fine particles such as silt and clay generated from the site, by reusing the classified mud water W1 for the drilling fluid A and the solidified material K, the amount of bentonite added is reduced. can do.

  Thus, in the present embodiment, corresponding to claim 1, the cutter 32 is rotated and the cutter 32 is moved in a state where the chain type cutter 32 is built in the ground, so that a groove G having a constant width is obtained. In the construction method of the underground continuous wall in which the wall forming pillar material is inserted into the groove G to form the underground wall 1, the wall forming pillar material is the PC wall body 2. The muddy water W generated during excavation when the solidifying material K is injected and the PC wall 2 is inserted is collected, and the sediment D is separated from the collected muddy water W. The separated sediment D and sediment D are separated. Since the separated muddy water W1 that is the separated liquid is reused, a large amount of waste is generated when the PC wall body 2 having a large cross section is used. However, the muddy water W generated by excavation is recovered, and the separated liquid and earth and sand are collected. Conventionally, the muddy water W that had to be discarded or treated to separate it into D For example, the separation liquid contains the components of the drilling fluid and fine particles such as silt and clay that are generated on site, so it can be reused in the separation liquid, and the amount of added components used. In addition, the earth and sand content D can be reused as a civil engineering material, and the same actions and effects as those of the first embodiment can be achieved in correspondence with claims 4 and 5.

  In this way, in this embodiment, corresponding to claim 3, the solidifying material K is injected into the excavated soil in the groove G while moving the cutter 32, and the PC is inserted into the groove G into which the solidifying material K has been injected. Since the underground wall 2 is formed by inserting the wall body 2, the muddy water W containing the solidifying material K is collected, separated into the separation liquid and the sediment D, and the sediment D or the separated water is reused. Can do.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, various types of PC wall bodies can be used.

It is explanatory drawing of the construction apparatus which shows Example 1 of this invention, and shows a construction state. A plan view of the groove in the construction state is shown. It is sectional drawing explaining a construction method same as the above, and FIG. 3 (A) shows the state which attached the cutter to the vertical frame and built it in the ground. It is sectional drawing at the time of construction which looked at the construction apparatus from the front same as the above. It is sectional drawing at the time of construction which looked at the construction apparatus from the side same as the above. It is a top view of a construction apparatus same as the above. It is sectional drawing which shows Example 1 of this invention and demonstrates a construction method, FIG. 7 (A) shows the state which attached the cutter to the vertical frame, and built it in the ground, FIG.7 (B) is a cutter. FIG. 3C shows a process of excavating in the excavation direction after back excavation and inserting the PC wall body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Underground continuous wall 2 PC wall body 3 Hollow part 4 Joint surface 5 Joint groove
10 Drilling rig
32 Endless chain cutter (cutter)
A Stabilizer K Solidifying material G Groove D Earth and sand W Muddy water
70 Squeeze pump
78 Mud tank
79 Stirrer

Claims (5)

With the chain cutter built in the ground, the cutter is rotated and the cutter is moved to continuously excavate a groove with a constant width, and a wall forming pillar is inserted into the groove. In the construction method of the underground continuous wall that forms the underground wall, the pillar material for wall formation is a PC wall body, the muddy water generated at the time of excavation is recovered, and the sediment is separated from the recovered muddy water. A method for constructing an underground continuous wall characterized in that the separated earth and sand and the separated liquid from which the earth and sand are separated are reused. 2. The underground continuous wall construction method according to claim 1, wherein after the PC wall body is inserted into the groove, the groove is filled with a solidifying material. 2. The solidified material is injected into the excavated soil in the groove while moving the cutter, and the underground wall is formed by inserting the PC wall into the groove into which the solidified material has been injected. The underground continuous wall construction method described. The construction method of the underground continuous wall according to any one of claims 1 to 3, wherein the generated muddy water is sucked by a squeeze pump. In the construction apparatus used for the construction method of the underground continuous wall of Claim 1, the squeeze pump which collect | recovers the generated muddy water, the mud tank which stores the muddy water collect | recovered with this squeeze pump, and the muddy water of this mud tank A construction apparatus for an underground continuous wall, comprising: a sediment separation means for separating sediment from the soil.

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